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Sample records for 3pn rydberg transitions

  1. Transition rates for a Rydberg atom surrounded by a plasma

    NASA Astrophysics Data System (ADS)

    Lin, Chengliang; Gocke, Christian; Röpke, Gerd; Reinholz, Heidi

    2016-04-01

    We derive a quantum master equation for an atom coupled to a heat bath represented by a charged particle many-body environment. In the Born-Markov approximation, the influence of the plasma environment on the reduced system is described by the dynamical structure factor. Expressions for the profiles of spectral lines are obtained. Wave packets are introduced as robust states allowing for a quasiclassical description of Rydberg electrons. Transition rates for highly excited Rydberg levels are investigated. A circular-orbit wave-packet approach has been applied in order to describe the localization of electrons within Rydberg states. The calculated transition rates are in a good agreement with experimental data.

  2. Direct detection of Rydberg-Rydberg millimeter-wave transitions in a buffer gas cooled molecular beam

    NASA Astrophysics Data System (ADS)

    Zhou, Yan; Grimes, David D.; Barnum, Timothy J.; Patterson, David; Coy, Stephen L.; Klein, Ethan; Muenter, John S.; Field, Robert W.

    2015-11-01

    Millimeter-wave transitions between molecular Rydberg states (n ∼ 35) of barium monofluoride are directly detected via Free Induction Decay (FID). Two powerful technologies are used in combination: Chirped-Pulse millimeter-Wave (CPmmW) spectroscopy and a buffer gas cooled molecular beam photoablation source. Hundreds of Rydberg-Rydberg transitions are recorded in 1 h with >10:1 signal:noise ratio and ∼150 kHz resolution. This high resolution, high spectral velocity experiment promises new strategies for rapid measurements of structural and dynamical information, such as the electric structure (multipole moments and polarizabilities) of the molecular ion-core and the strengths and mechanisms of resonances between Rydberg electron and ion-core motions. Direct measurements of Rydberg-Rydberg transitions with kilo-Debye dipole moments support efficient and definitive spectral analysis techniques, such as the Stark demolition and polarization diagnostics, which enable semi-automatic assignments of core-nonpenetrating Rydberg states. In addition, extremely strong radiation-mediated collective effects (superradiance) in a dense Rydberg gas of barium atoms are observed.

  3. Transition rates in proton - Rydberg atom collisions

    NASA Astrophysics Data System (ADS)

    Vrinceanu, Daniel

    2016-05-01

    Monte Carlo simulations for energy and angular momentum transfer processes in proton - Ryderg atom collisions were performed and the corresponding rates are reported.The relevance of these rates in the context of cosmological recombination is discussed. The rates are contrasted with the similar rates in electron - Rydberg atom collisions. This work has been supported by National Science Foundation through grants for the Center for Research on Complex Networks (HRD-1137732) and Research Infrastructure for Science and Engineering (RISE) (HRD-1345173).

  4. Landau-Zener Transitions in Frozen Pairs of Rydberg Atoms

    SciTech Connect

    Saquet, Nicolas; Cournol, Anne; Beugnon, Jerome; Robert, Jacques; Pillet, Pierre; Vanhaecke, Nicolas

    2010-04-02

    We have induced adiabatic transitions in pairs of frozen Rydberg sodium atoms of a supersonic beam. The diatomic ns+ns{yields}np+(n-1)p transition takes place in a time-dependent electric field and originates from the adiabatic change of the internal state of the pair induced by the dipole-dipole interaction. This is experimentally achieved by sweeping an electric field across the energy degeneracy ns ns-np(n-1)p. Our results fully agree with a two-level Landau-Zener model in the diatom system.

  5. Landau-Zener transitions in frozen pairs of Rydberg atoms.

    PubMed

    Saquet, Nicolas; Cournol, Anne; Beugnon, Jérôme; Robert, Jacques; Pillet, Pierre; Vanhaecke, Nicolas

    2010-04-01

    We have induced adiabatic transitions in pairs of frozen Rydberg sodium atoms of a supersonic beam. The diatomic ns+ns-->np+(n-1)p transition takes place in a time-dependent electric field and originates from the adiabatic change of the internal state of the pair induced by the dipole-dipole interaction. This is experimentally achieved by sweeping an electric field across the energy degeneracy ns ns-np(n-1)p. Our results fully agree with a two-level Landau-Zener model in the diatom system. PMID:20481882

  6. The Rydberg electronic transitions of the hydrogen molecule

    SciTech Connect

    Babb, J.F.; Chang, E.S. )

    1992-01-01

    Transition energies and relative line strengths, without Boltzmann weighting, for the electric dipole transitions between Rydberg states n{prime}L{prime} and nL of the hydrogen molecule (one electron in a near-hydrogenic state of high n and L, with n the principal quantum number and L the orbital angular momentum quantum number of the electron) are calculated. Since the H{sup +}{sub 2} core is loosely coupled to the Rydberg electron, numerous lines occur, depending on the vector sum of L and the core rotational angular momentum. For the core vibrational quantum numbers v = 0 to 5 the strongest lines among the P, Q, and R branches for the lowest 12 core rotational levels are given for the particular transition arrays 6h-5g, 8i-6h, 7i-6h, 8k-7i, and 9l-8k, for which transitions occur in the wave number range 350 to 1,400 cm {sup {minus}1}.

  7. Two-color photoexcitation of Rydberg states via an electric quadrupole transition

    SciTech Connect

    Li Leping; Gu Quanli; Knee, J. L.; Wright, J. D.; DiSciacca, J. M.; Morgan, T. J.

    2008-03-15

    We report the observation of an electric quadrupole transition between the 4s{sup '}[1/2]{sub 0}{sup o} and 3d[3/2]{sub 2}{sup o} states in the spectrum of argon and use it in the first step of a scheme to excite Rydberg states. The initial identification of the transition is based on one-color, two-photon photoionization. A different experiment utilizing two-color, two-photon photoexcitation to Rydberg states confirms the identification. Despite the unavoidable background of one-color, two-photon photoionization, the latter experimental technique makes possible two-photon spectroscopy of Rydberg states using a resonant intermediate state populated by an electric quadrupole transition.

  8. Doppler- and recoil-free laser excitation of Rydberg states via three-photon transitions

    SciTech Connect

    Ryabtsev, I. I.; Beterov, I. I.; Tretyakov, D. B.; Entin, V. M.; Yakshina, E. A.

    2011-11-15

    Three-photon laser excitation of Rydberg states by three different laser beams can be arranged in a starlike geometry that simultaneously eliminates the recoil effect and Doppler broadening. Our analytical and numerical calculations for a particular laser excitation scheme 5S{sub 1/2}{yields}5P{sub 3/2}{yields}6S{sub 1/2}{yields}nP in Rb atoms have shown that, compared to the one- and two-photon laser excitation, this approach provides much narrower linewidth and longer coherence time for both cold atom samples and hot vapors, if the intermediate one-photon resonances of the three-photon transition are detuned by more than respective single-photon Doppler widths. This method can be used to improve fidelity of Rydberg quantum gates and precision of spectroscopic measurements in Rydberg atoms.

  9. Oscillator Strengths and Predissociation Widths for Rydberg Transitions in Carbon Monoxide

    NASA Technical Reports Server (NTRS)

    Federman, Steven R.; Sheffer, Y.; Eidelsberg, Michele; Lemaire, Jean-Louis; Fillion, Jean-Hugues; Rostas, Francois; Ruiz, J.

    2006-01-01

    CO is used as a probe of astronomical environments ranging from planetary atmospheres and comets to interstellar clouds and the envelopes surrounding stars near the end of their lives. One of the processes controlling the CO abundance and the ratio of its isotopomers is photodissociation. Accurate oscillator strengths for Rydberg transitions are needed for modeling this process. Absorption bands were analyzed by synthesizing the profiles with codes developed independently in Meudon and Toledo. Each synthetic spectrum was adjusted to match the experimental one in a non-linear least-squares fitting procedure with the band oscillator strength, the line width (instrumental and predissociation.

  10. Landau-Zener-Stueckelberg theory for multiphoton intrashell transitions in Rydberg atoms: Bloch-Siegert shifts and widths

    SciTech Connect

    Foerre, Morten

    2004-07-01

    We derive closed analytic expressions for intrashell transitions in Rydberg atoms exposed to linearly polarized or circularly polarized periodic electromagnetic fields. The resonance energies and transition probabilities are calculated using multichannel Landau-Zener-Stueckelberg theory. The theory provides formulas for the resonance widths and positions for arbitrary field strength and frequency. The formulas are in excellent agreement with numerical solution of the evolution equations.

  11. Microwave Transitions Between Pair States Composed of Two rb Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Lee, Jeonghun; Gallagher, Tom

    2015-06-01

    Microwave transitions between pair states composed of two Rb Rydberg atoms in a magneto-optical trap are investigated. Our current interest is the transition from ndnd to (n+1)d(n-2)f states. This transition is allowed because the dipole-dipole induced configuration interaction between the ndnd state and the energetically close (n+2)p(n-2)f state admixes some of the latter state into the former. The resonance frequencies of the ndnd-(n+1)d(n-2)f transitions for n=35 to 42 have been measured and found to agree well with the calculated values. In addition, the power shifts of the resonance frequencies have been measured for n=35 to 42. The dependence of the fractional population transfer from the ndnd to (n+1)d(n-2)f states on the microwave field strength and atomic density has been measured and can be compared to a simple theoretical model. This work has been supported by the Air Force Office of Scientific Research.

  12. Microwave transitions between pair states composed of two Rb Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Lee, Jeonghun; Gallagher, Tom

    2015-05-01

    Microwave transitions between pair states composed of two Rb Rydberg atoms in a magneto-optical trap are investigated. Our current interest is the transition from ndnd to (n+1)d(n-2)f states. This transition is allowed because the dipole-dipole induced configuration interaction between the ndnd state and the energetically close (n+2)p(n-2)f state admixes some of the latter state into the former. The resonance frequencies of the ndnd-(n+1)d(n-2)f transitions for n = 35 to 42 have been measured and found to agree well with the calculated values. In addition, the power shifts of the resonance frequencies have been measured for n = 35 to 42. The dependence of the fractional population transfer from the ndnd to (n+1)d(n-2)f states on the microwave field strength and atomic density has been measured and can be compared to a simple theoretical model. This work has been supported by the Air Force Office of Scientific Research.

  13. Theory of quantum oscillations in self-broadening of 4{sup 2}S-n{sup 2}S Rydberg transitions in potassium

    SciTech Connect

    Herman, R. M.; Henry, M. E.

    1997-01-05

    A pseudohamiltonian impact theory for describing Rydberg transition line shapes is proposed. Preliminary results give lineshapes in reasonable agreement with experiment, including the quantum oscillations in alkali self broadening and shifting, and rare gas broadening.

  14. ANGULAR MOMENTUM CHANGING TRANSITIONS IN PROTON-RYDBERG HYDROGEN ATOM COLLISIONS

    SciTech Connect

    Vrinceanu, D.; Onofrio, R.; Sadeghpour, H. R. E-mail: onofrior@gmail.com

    2012-03-01

    Collisions between electrically charged particles and neutral atoms are central for understanding the dynamics of neutral gases and plasmas in a variety of physical situations of terrestrial and astronomical interest. Specifically, redistribution of angular momentum states within the degenerate shell of highly excited Rydberg atoms occurs efficiently in distant collisions with ions. This process is crucial in establishing the validity of the local thermal equilibrium assumption and may also play a role in determining a precise ionization fraction in primordial recombination. We provide an accurate expression for the non-perturbative rate coefficient of collisions between protons and H(nl) ending in a final state H(nl'), with n being the principal quantum number and l, l' the initial and final angular momentum quantum numbers, respectively. The validity of this result is confirmed by results of classical trajectory Monte Carlo simulations. Previous results, obtained by Pengelly and Seaton only for dipole-allowed transitions l {yields} l {+-} 1, overestimate the l-changing collisional rate coefficients approximately by a factor of six, and the physical origin of this overestimation is discussed.

  15. Effect of photoions on the line shape of the Foerster resonance lines and microwave transitions in cold rubidium Rydberg atoms

    SciTech Connect

    Tretyakov, D. B.; Beterov, I. I.; Entin, V. M.; Yakshina, E. A.; Ryabtsev, I. I.; Dyubko, S. F.; Alekseev, E. A.; Pogrebnyak, N. L.; Bezuglov, N. N.; Arimondo, E.

    2012-01-15

    Experiments are carried out on the spectroscopy of the Foerster resonance lines Rb(37P) + Rb(37P) {yields} Rb(37S) + Rb(38S) and microwave transitions nP {yields} n Prime S, n Prime D between Rydberg states of cold rubidium atoms in a magneto-optical trap (MOT). Under ordinary conditions, all spectra exhibit a linewidth of 2-3 MHz irrespective of the interaction time between atoms or between atoms and microwave radiation, although the limit resonance width should be determined by the inverse interaction time. The analysis of experimental conditions has shown that the main source of line broadening is the inhomogeneous electric field of cold photoions that are generated under the excitation of initial nP Rydberg states by broadband pulsed laser radiation. The application of an additional electric-field pulse that rapidly extracts photoions produced by a laser pulse leads to a considerable narrowing of lines of microwave resonances and the Foerster resonance. Various sources of line broadening in cold Rydberg atoms are analyzed.

  16. Dipole and Quadrupole transition strengths in Ba^+ from measurements of K-splittings in high-L Ba Rydberg levels

    NASA Astrophysics Data System (ADS)

    Woods, Shannon L.; Lundeen, Stephen R.; Sturrus, William G.; Snow, Erica L.

    2009-05-01

    Measurements of K-splittings in high-L Rydberg levels of Ba have been used to determine electric dipole (6s-6p) and quadrupole (6s-5d) transition strengths in Ba^+ [1]. In that report, good agreement with calculated values was found for the dipole strength but not for the quadrupole strength. Using the data pattern extended to higher L levels recently [2] and a more complete theoretical model, we find good agreement between the measured K-splittings and the most recent theoretical calculations of relevant transition strengths.[3] [1] E.S. Shuman and T.F. Gallagher, Phys. Rev. A 74, 022502 (2006) [2] E.L. Snow, et. al., Phys. Rev. 71, 022510 (2005) [3] E. Iskrenova-Tchoukova and M. S. Safronova, et. al. Phys. Rev. A 78, 012508 (2008)

  17. Vibronic valence and Rydberg transitions in geminal chloro-fluoro-ethene (1,1-C2H2FCl): a spectroscopic and quantum chemical investigation

    NASA Astrophysics Data System (ADS)

    Locht, R.; Dehareng, D.; Leyh, B.

    2014-06-01

    The vacuum ultraviolet photoabsorption spectrum of 1,1-C2H2FCl has been examined in detail between 5 and 15 eV photon energy by using synchrotron radiation dispersed by three different monochromators. Quantum chemical calculations are performed to help in the analysis of the valence/Rydberg transition region centred at 7.05 eV including the 3a″(π)→π* and the 3a″(π)→3s Rydberg transitions. Interactions between states involving transitions to the 3s, 4d and σ* orbitals are identified. A vibrational analysis is proposed for the structures belonging to these transitions. For the π(3a″)→π* transition, one vibrational progression is observed with ω3 = 1410 ± 50 cm-1 and its lowest excitation energy is determined at about 6.398 ± 0.003 eV. The π(3a″)→3s Rydberg transition is characterised by a single progression with ω3 = 1410 ± 80 cm-1 likely starting at about 6.45 eV. These vibrations are ascribed to the C=C stretching motion. The abundant structure observed in the spectrum between 7.8 and 10.5 eV has been analysed in terms of vibronic transitions to ns (δ = 0.97), np (δ = 0.63 and 0.40) and nd (δ = 0.13 and -0.11) Rydberg states, which belong to series converging to the 1,1-C2H2FCl+(?) ionic ground state. The analysis of the vibrational structure of the individual Rydberg states has been attempted leading to average values of the wave numbers ω3 = 1420 ± 20 cm-1, ω7 = 720 ± 50 cm-1 and ω9 = 390 ± 50 cm-1. Between 10.5 and 12.5 eV, nine other Rydberg states converging to the 1,1-C2H2FCl+(?) first excited state were analysed by the same way. The vibrational structure of these Rydberg states results from the excitation of one vibrational normal mode ν7 with an average value of ω7 = 520 ± 20 cm-1, which is assigned to the C-Cl stretching vibration as inferred from quantum chemical calculations.

  18. Measurement of absolute transition frequencies of {sup 87}Rb to nS and nD Rydberg states by means of electromagnetically induced transparency

    SciTech Connect

    Mack, Markus; Karlewski, Florian; Hattermann, Helge; Hoeckh, Simone; Jessen, Florian; Cano, Daniel; Fortagh, Jozsef

    2011-05-15

    We report the measurement of absolute excitation frequencies of {sup 87}Rb to nS and nD Rydberg states. The Rydberg transition frequencies are obtained by observing electromagnetically induced transparency on a rubidium vapor cell. The accuracy of the measurement of each state is < or approx. 1 MHz, which is achieved by frequency stabilizing the two diode lasers employed for the spectroscopy to a frequency comb and a frequency comb calibrated wavelength meter, respectively. Based on the spectroscopic data we determine the quantum defects of {sup 87}Rb, and compare it with previous measurements on {sup 85}Rb. We determine the ionization frequency from the 5S{sub 1/2}(F=1) ground state of {sup 87}Rb to 1010.029 164 6(3)THz, providing the binding energy of the ground state with an accuracy improved by two orders of magnitude.

  19. Precision spectroscopy of 2S-nP transitions in atomic hydrogen for a new determination of the Rydberg constant and the proton charge radius

    NASA Astrophysics Data System (ADS)

    Beyer, Axel; Maisenbacher, Lothar; Khabarova, Ksenia; Matveev, Arthur; Pohl, Randolf; Udem, Thomas; Hänsch, Theodor W.; Kolachevsky, Nikolai

    2015-10-01

    Precision measurements of transition frequencies in atomic hydrogen provide important input for a number of fundamental applications, such as stringent tests of QED and the extraction of fundamental constants. Here we report on precision spectroscopy of the 2S-4P transition in atomic hydrogen with a reproducibility of a few parts in 1012. Utilizing a cryogenic beam of hydrogen atoms in the metastable 2S state reduces leading order systematic effects of previous experiments of this kind. A number of different systematic effects, especially line shape modifications due to quantum interference in spontaneous emission, are currently under investigation. Once fully characterized, our measurement procedure can be applied to higher lying 2S-nP transitions (n=6,8,9,10) and we hope to contribute to an improved determination of the Rydberg constant and the proton root mean square charge radius by this series of experiments. Ultimately, this improved determination will give deeper insight into ‘the proton size puzzle’ from the electronic hydrogen side.

  20. Rydberg Spectroscopy in an Optical Lattice: Blackbody Thermometry for Atomic Clocks

    SciTech Connect

    Ovsiannikov, Vitali D.; Derevianko, Andrei; Gibble, Kurt

    2011-08-26

    We show that optical spectroscopy of Rydberg states can provide accurate in situ thermometry at room temperature. Transitions from a metastable state to Rydberg states with principal quantum numbers of 25-30 have 200 times larger fractional frequency sensitivities to blackbody radiation than the strontium clock transition. We demonstrate that magic-wavelength lattices exist for both strontium and ytterbium transitions between the metastable and Rydberg states. Frequency measurements of Rydberg transitions with 10{sup -16} accuracy provide 10 mK resolution and yield a blackbody uncertainty for the clock transition of 10{sup -18}.

  1. Oscillator strengths for transitions to Rydberg levels in 12C 16O, 13C 16O and 13C 18O between 967 and 972 Å

    NASA Astrophysics Data System (ADS)

    Eidelsberg, M.; Lemaire, J. L.; Fillion, J. H.; Rostas, F.; Federman, S. R.; Sheffer, Y.

    2004-09-01

    Absorption oscillator strengths have been determined from high-resolution spectra in the 967-972 Å region of three CO isotopomers for transitions to the Rydberg levels 4pπ(0), 3dπ(1)b and 4pσ(0), as well as to the mixed E(6) level recently characterized by Eidelsberg et al. (\\cite{Eid04}). Synchrotron radiation from the Super-ACO electron storage ring at Orsay (LURE) was used as a light source. Oscillator strengths were extracted from the recorded spectra by least-squares fitting of the experimental profiles with synthetic spectra taking into account the homogeneous and heterogeneous interactions of the four levels. Column densities were derived from fits to the 3pπ(0) absorption band whose oscillator strength is well established. These are the first reported measurements for 13C18O. For 12C16Op, our results are consistent with the larger values obtained in the most recent laboratory and astronomical studies. Based on experiments done at the Super-ACO electron storage ring at Orsay (LURE), France.

  2. Dislocation-mediated melting of one-dimensional Rydberg crystals

    SciTech Connect

    Sela, Eran; Garst, Markus; Punk, Matthias

    2011-08-15

    We consider cold Rydberg atoms in a one-dimensional optical lattice in the Mott regime with a single atom per site at zero temperature. An external laser drive with Rabi frequency {Omega} and laser detuning {Delta} creates Rydberg excitations whose dynamics is governed by an effective spin-chain model with (quasi) long-range interactions. This system possesses intrinsically a large degree of frustration resulting in a ground-state phase diagram in the ({Delta},{Omega}) plane with a rich topology. As a function of {Delta}, the Rydberg blockade effect gives rise to a series of crystalline phases commensurate with the optical lattice that form a so-called devil's staircase. The Rabi frequency {Omega}, on the other hand, creates quantum fluctuations that eventually lead to a quantum melting of the crystalline states. Upon increasing {Omega}, we find that generically a commensurate-incommensurate transition to a floating Rydberg crystal that supports gapless phonon excitations occurs first. For even larger {Omega}, dislocations within the floating Rydberg crystal start to proliferate and a second, Kosterlitz-Thouless-Nelson-Halperin-Young dislocation-mediated melting transition finally destroys the crystalline arrangement of Rydberg excitations. This latter melting transition is generic for one-dimensional Rydberg crystals and persists even in the absence of an optical lattice. The floating phase and the concomitant transitions can, in principle, be detected by Bragg scattering of light.

  3. Rydberg states via CPmmW spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhou, Yan; Grimes, David; Field, Robert

    2014-05-01

    Rydberg-Rydberg transitions of Ca atoms are directly observed by chirped-pulse millimeter-wave spectroscopy, which is a form of broadband, high-resolution, free induction decay (FID) spectroscopy with accurate relative intensities. At moderate to high number densities (~106 cm-3), interactions between many Rydberg atoms are mediated by an AC electric field, absorbing and radiating cooperatively. A semiclassical model describes several significant time-domain and frequency-domain cooperative effects in two-level systems and Λ-type three-level systems. Experimental evidence that supports this model will be discussed. A new experiment, employing the buffer gas cooling technique has been constructed and I expect to present preliminary results. In partically, the >100-fold increase in number density will permit study of ``pure electronic'' spectra of Rydberg molecules, such as BaF. We expect to produce 108 state selected core-nonpenetrating Rydberg molecules in a single pulse of a laser-laser-mm-wave excitation sequence.

  4. Coherence in Rydberg Atoms: Measurement and Control

    NASA Astrophysics Data System (ADS)

    Kutteruf, Mary

    We demonstrate a variety of techniques for measuring and controlling dephasing and decoherence in alkali metal Rydberg atom systems. Specifically, we investigate the coherence of the spin-orbit interaction in individual atoms and of dipole-dipole resonant energy exchange between pairs of atoms. Rydberg atoms are a good model system for exploring decoherence because they are sensitive to noise in their environments. The phase coherence of wave packets encoded on the fine-structure Rydberg states of lithium atoms is measured using a population echo and preserved using pulsed and continuous dynamic decoupling techniques. Pulsed electric fields toggle the spin-orbit coupling, repeatedly flipping the state vector, and preventing the slow acquisition of phase noise in a bang-bang scheme. Continuous dynamic decoupling is implemented by driving population between the relevant electronic states with a resonant rf field. The energy spacing between the levels is locked to the rf frequency as long as the Rabi rate is much greater than the dephasing rate. We demonstrate a technique which reduces the average relative velocity between interacting potassium Rydberg atoms, extending the atom transit time and allowing us to control when all resonant energy exchange interactions in the ensemble begin and end. Velocity reduction is achieved without the use of a chopper wheel by exciting a small cylinder of atoms and allowing them to thermally expand prior to tuning them into resonance. Resonant energy transfer is explored further in a nearly frozen rubidium Rydberg gas. We observe enhancement in the transition signal when the probability amplitudes acquired on opposite sides of the resonance interfere constructively compared to the population transferred when remaining on either side of the resonance. This enhancement reflects the coherence of the energy exchange interaction and decays over 10 us microseconds. The observed coherence time is much longer than previously measured

  5. Newly Identified Rydberg Emission Lines in Novae

    NASA Astrophysics Data System (ADS)

    Lynch, David K.; Rudy, R. J.; Bernstein, L. S.

    2008-09-01

    Newly Identified Rydberg Emission Lines in Novae David K. Lynch, Richard. J. Rudy (The Aerospace Corporation) & Lawrence S. Bernstein (Spectral Sciences, Inc.) Novae spectra in the near infrared frequently show a set of six emission lines that have not been positively identified (Williams, Longmore, & Geballe 1996, MNRAS, 279, 804; Lynch et al. 2001, AJ, 122, 2013; Rudy et al. 2002 ApJ, 573, 794; Lynch et al. 2004 Astron. J. 127, 1089-1097). These lines are at 0.8926, 1.1114, 1.1901, 1.5545, 2.0996 and 2.425 µm ± 0.005 µm. Krautter et al. (1984 A&A 137, 304) suggested that three of the lines were due to rydberg (hydrogenic) transitions in an unspecified atomic species that was in the 4th or 5th ionization stage (core charge = 4 & 5). We believe that Krautter et al.'s explanation is correct based on 4 additional lines that we have identified in the visible and near infrared spectrum of V723 Cassiopeiae. The observed Rydberg lines appear to originate from high angular momentum states with negligible quantum defects. The species cannot be determined with any certainty because in rydberg states, the outer electron sees a nucleus shielded by the inner electrons and together the inner atom appears to have a charge of +1, like hydrogen. As a result, the atom looks hydrogenic and species such as CV, NV, OV, MgV, SiV, etc. have their rydberg transitions at very similar wavelengths. All the lines represent permitted transitions, most likely formed by recombination. Atoms with core charges 4, 5 & 6 are rarely seen in the astrophysical environment because an extremely hot radiation field is necessary to ionize them. Thermonuclear runaways on the surface of a white dwarf can reach millions of degrees K, and thus there are enough X-ray photons available to achieve the necessary high ionization levels.

  6. Progress towards measuring the Rydberg Constant Using Circular Rydberg Atoms in an Intensity-Modulated Optical Lattice

    NASA Astrophysics Data System (ADS)

    Ramos, Andira; Moore, Kaitlin; Raithel, Georg

    2015-05-01

    Recent significant disagreement with the previously established size of the proton demonstrates a need to reconsider the current value of the Rydberg constant, the effects of the nuclear charge distribution and QED in hydrogen-like atoms. An experiment is in progress to obtain a measurement of the Rydberg constant by studying circular Rydberg atoms, which exhibit very small QED shifts and electron wavefunctions which do not overlap with the nucleus. Cold Rydberg atoms are trapped using a ponderomotive potential. To drive the transitions, a novel type of spectroscopy is used which utilizes an optical-lattice field that is intensity-modulated at the frequencies of atomic transitions. The method is free of typical spectroscopic selection rules and has been shown to drive transitions up to fifth order. Combined with optical Rydberg-atom trapping, the method enables the measurement of narrow, sub-THz transitions between long-lived circular Rydberg levels. Energy shifts affecting this precision measurement will also be discussed. This work is suported by NSF, NIST and NASA grants.

  7. Observation of Cavity Rydberg Polaritons

    NASA Astrophysics Data System (ADS)

    Georgakopoulos, Alexandros; Jia, Ningyuan; Ryou, Albert; Schine, Nathan; Sommer, Ariel; Simon, Jonathan

    2016-05-01

    We demonstrate hybridization of optical cavity photons with atomic Rydberg excitations using electromagnetically induced transparency (EIT). The resulting dark state Rydberg polaritons exhibit a compressed frequency spectrum and enhanced lifetime indicating strong light-matter mixing. We study the coherence properties of cavity Rydberg polaritons and identify the generalized EIT linewidth for optical cavities. Strong collective coupling suppresses polariton losses due to inhomogeneous broadening, which we demonstrate by using different Rydberg levels with a range of polarizabilities. Our results point the way towards using cavity Rydberg polaritons as a platform for creating photonic quantum materials.

  8. Rydberg excitation of trapped strontium ions (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hennrich, Markus; Higgins, Gerard; Pokorny, Fabian; Kress, Florian; Maier, Christine; Haag, Johannes; Colombe, Yves

    2016-04-01

    Trapped Rydberg ions are a novel approach for quantum information processing [1,2]. This idea joins the advanced quantum control of trapped ions with the strong dipolar interaction between Rydberg atoms. For trapped ions this method promises to speed up entangling interactions [3] and to enable such operations in larger ion crystals [4]. We report on the first experimental realization of trapped strontium Rydberg ions. A single ion was confined in a linear Paul trap and excited to Rydberg states (25S to 37S) using a two-photon excitation with 243nm and 308nm laser light. The transitions we observed are narrow and the excitation can be performed repeatedly which indicates that the Rydberg ions are stable in the ion trap. Similar results have been recently reported on a single photon Rydberg excitation of trapped calcium ions [5]. The tunability of the 304-309nm laser should enable us to excite our strontium ions to even higher Rydberg levels. Such highly excited levels are required to achieve a strong interaction between neighboring Rydberg ions in the trap as will be required for quantum gates using the Rydberg interaction. References [1] M. Müller, L. Liang, I. Lesanovsky, P. Zoller, New J. Phys. 10, 093009 (2008). [2] F. Schmidt-Kaler, et al., New J. Phys. 13, 075014 (2011). [3] W. Li, I. Lesanovsky, Appl. Phys. B 114, 37-44 (2014). [4] W. Li, A.W. Glaetzle, R. Nath, I. Lesanovsky, Phys. Rev. A 87, 052304 (2013). [5] T. Feldker, et al., arXiv:1506.05958

  9. Addressing single trapped ions for Rydberg quantum logic

    NASA Astrophysics Data System (ADS)

    Bachor, P.; Feldker, T.; Walz, J.; Schmidt-Kaler, F.

    2016-08-01

    We demonstrate the excitation of ions to the Rydberg state 22F by vacuum ultraviolet radiation at a wavelength of 123 nm combined with the coherent manipulation of the optical qubit transition in {}40{{Ca}}+. With a tightly focused beam at 729 nm wavelength we coherently excite a single ion from a linear string into the metastable 3{D}5/2 state before a VUV pulse excites it to the Rydberg state. In combination with ion shuttling in the trap, we extend this approach to the addressed excitation of multiple ions. The coherent initialization as well as the addressed Rydberg excitation are key prerequisites for more complex applications of Rydberg ions in quantum simulation or quantum information processing.

  10. Anomalous Broadening in Driven Dissipative Rydberg Systems.

    PubMed

    Goldschmidt, E A; Boulier, T; Brown, R C; Koller, S B; Young, J T; Gorshkov, A V; Rolston, S L; Porto, J V

    2016-03-18

    We observe interaction-induced broadening of the two-photon 5s-18s transition in ^{87}Rb atoms trapped in a 3D optical lattice. The measured linewidth increases by nearly 2 orders of magnitude with increasing atomic density and excitation strength, with corresponding suppression of resonant scattering and enhancement of off-resonant scattering. We attribute the increased linewidth to resonant dipole-dipole interactions of 18s atoms with blackbody induced population in nearby np states. Over a range of initial atomic densities and excitation strengths, the transition width is described by a single function of the steady-state density of Rydberg atoms, and the observed resonant excitation rate corresponds to that of a two-level system with the measured, rather than natural, linewidth. The broadening mechanism observed here is likely to have negative implications for many proposals with coherently interacting Rydberg atoms. PMID:27035299

  11. Anomalous Broadening in Driven Dissipative Rydberg Systems

    NASA Astrophysics Data System (ADS)

    Goldschmidt, E. A.; Boulier, T.; Brown, R. C.; Koller, S. B.; Young, J. T.; Gorshkov, A. V.; Rolston, S. L.; Porto, J. V.

    2016-03-01

    We observe interaction-induced broadening of the two-photon 5 s -18 s transition in 87Rb atoms trapped in a 3D optical lattice. The measured linewidth increases by nearly 2 orders of magnitude with increasing atomic density and excitation strength, with corresponding suppression of resonant scattering and enhancement of off-resonant scattering. We attribute the increased linewidth to resonant dipole-dipole interactions of 18 s atoms with blackbody induced population in nearby n p states. Over a range of initial atomic densities and excitation strengths, the transition width is described by a single function of the steady-state density of Rydberg atoms, and the observed resonant excitation rate corresponds to that of a two-level system with the measured, rather than natural, linewidth. The broadening mechanism observed here is likely to have negative implications for many proposals with coherently interacting Rydberg atoms.

  12. Standoff detection of large organic molecules using Rydberg fingerprint spectroscopy and microwave Rayleigh scattering

    SciTech Connect

    Rudakov, Fedor M; Zhang, Zhili

    2012-01-01

    We present a technique for nonintrusive and standoff detection of large organic molecules using coherent microwave Rayleigh scattering from plasma produced by structure sensitive photoionization through Rydberg states. We test the method on 1,4-diazobicyclooctane. Transitions between the 3s Rydberg state and higher lying Rydberg states are probed using two-color photoionization with 266?nm photons and photons in the range of 460-2400 nm. Photoionization is detected using microwave radiation, which is scattered by the unbounded electrons. Highly resolved Rydberg spectra are acquired in vacuum and in air.

  13. STIRAP on helium: Excitation to Rydberg states

    NASA Astrophysics Data System (ADS)

    Yuan, Deqian

    Research in optically induced transitions between dierent atomic levels has a long history. For transitions between states driven by a coherent optical eld, the theoretical eciency could be ideally high as 100% but there could be many factors preventing this. In the three state helium atom excitation process, i.e. 23S→33P→nL , the stimulated emission from intermediate state makes it hard to achieve ecient population transfer to the nal state through an intuitive excitation order. One technique to achieve a higher eciency is Stimulated Raman Adiabatic Passage (STIRAP) which is being studied and under research in our lab. Unlike traditional three level excitation processes, STIRAP actually uses a counter intuitive pulsed laser beams timing arrangement. The excitation objects are metastable helium atoms traveling in a vacuum system with a longitudinal velocity of ~ 1070 m/s. We are using a 389 nm UV laser to connect the 23S and the 33P state and a frequency tunable ~790 nm IR laser to connect the 33P state and the dierent Rydberg states. A third 1083 nm wavelength laser beam drives the 23S → 23P transition to transversely separate the residual metastable atoms and the Rydberg atoms for eciency measurements. The data is taken by a stainless steel detector in the vacuum system. As the Rydberg atoms will get ionized by blackbody radiation under room temperature, we can utilize this for their detection. An ion detector sitting on the eld plate is capable to collect the ion signals of the Rydberg atoms for detection. So far the whole system has not been ready for data collection and measurement, so here we are using data and results from previous theses for discussions. The highest transition frequency that has ever been achieved in our lab is around 70% after corrections.

  14. THz Detection and Imaging using Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Wade, Christopher; Sibalic, Nikola; Kondo, Jorge; de Melo, Natalia; Adams, Charles; Weatherill, Kevin

    2016-05-01

    Atoms make excellent electromagnetic field sensors because each atom of the same isotope is identical and has well-studied, permanent properties allowing calibration to SI units. Thus far, atoms have not generally been exploited for terahertz detection because transitions from the atomic ground state are constrained to a limited selection of microwave and optical frequencies. In contrast, highly excited `Rydberg' states allow us access to many strong, electric dipole transitions from the RF to THz regimes. Recent advances in the coherent optical detection of Rydberg atoms have been exploited by a number of groups for precision microwave electrometry Here we report the demonstration of a room-temperature, cesium Rydberg gas as a THz to optical interface. We present two configurations: First, THz-induced fluorescence offers non-destructive and direct imaging of the THz field, providing real-time, single shot images. Second, we convert narrowband terahertz photons to infrared photons with 6% quantum efficiency allowing us to use nano-Watts of THz power to control micro-Watts of laser power on microsecond timescales. Exploiting hysteresis and a room-temperature phase transition in the response of the medium, we demonstrate a latching optical memory for sub pico-Joule THz pulses.

  15. Excitation of Ultracold Molecules to ``TRILOBITE-LIKE" Long-Range Molecular Rydberg States

    NASA Astrophysics Data System (ADS)

    Bellos, M. A.; Carollo, R.; Banerjee, J.; Eyler, E. E.; Gould, P. L.; Stwalley, W. C.

    2013-06-01

    A class of long-range Rydberg molecules, sometimes called ``trilobite states", occurs when a ground-state atom is embedded in the electronic cloud of a Rydberg atom. The bond between the Rydberg atom and the ground-state atom originates from the low-energy scattering of the Rydberg electron from the ground-state atom. We produce trilobite-like states of ultracold Rb_2 at low principal quantum numbers and at internuclear separations less than 40 bohr. We populate these states through single-photon ultraviolet transitions starting from molecules in high-lying vibrational levels of the lowest triplet state. This demonstrates that long-range Rydberg molecules can also be excited through bound-bound transitions, in addition to previous studies that used free-bound transitions. We also discuss the advantages of a bound-bound pathway. C. H. Greene, A. S. Dickinson, and H. R. Sadeghpour, Phys. Rev. Lett. 85, 2458 (2000).

  16. Cavity quantum electrodynamics with a Rydberg-blocked atomic ensemble

    SciTech Connect

    Guerlin, Christine; Brion, Etienne; Esslinger, Tilman; Moelmer, Klaus

    2010-11-15

    The realization of a Jaynes-Cummings model in the optical domain is proposed for an atomic ensemble. The scheme exploits the collective coupling of the atoms to a quantized cavity mode and the nonlinearity introduced by coupling to high-lying Rydberg states. A two-photon transition resonantly couples the single-atom ground state |g> to a Rydberg state |e> via a nonresonant intermediate state |i>, but due to the interaction between Rydberg atoms only a single atom can be resonantly excited in the ensemble. This restricts the state space of the ensemble to the collective ground state |G> and the collectively excited state |E> with a single Rydberg excitation distributed evenly on all atoms. The collectively enhanced coupling of all atoms to the cavity field with coherent coupling strengths which are much larger than the decay rates in the system leads to the strong coupling regime of the resulting effective Jaynes-Cummings model. We use numerical simulations to show that the cavity transmission can be used to reveal detailed properties of the Jaynes-Cummings ladder of excited states and that the atomic nonlinearity gives rise to highly nontrivial photon emission from the cavity. Finally, we suggest that the absence of interactions between remote Rydberg atoms may, due to a combinatorial effect, induce a cavity-assisted excitation blockade whose range is larger than the typical Rydberg dipole-dipole interaction length.

  17. Trapping Rydberg Atoms in an Optical Lattice

    SciTech Connect

    Anderson, S. E.; Younge, K. C.; Raithel, G.

    2011-12-23

    Rubidium Rydberg atoms are laser excited and subsequently trapped in a one-dimensional optical lattice (wavelength 1064 nm). Efficient trapping is achieved by a lattice inversion immediately after laser excitation using an electro-optic technique. The trapping efficiency is probed via analysis of the trap-induced shift of the two-photon microwave transition 50S{yields}51S. The inversion technique allows us to reach a trapping efficiency of 90%. The dependence of the efficiency on the timing of the lattice inversion and on the trap laser power is studied. The dwell time of 50D{sub 5/2} Rydberg atoms in the lattice is analyzed using lattice-induced photoionization.

  18. Ionization of Rydberg atoms by standing-wave light fields.

    PubMed

    Anderson, Sarah E; Raithel, Georg

    2013-01-01

    When electromagnetic radiation induces atomic transitions, the size of the atom is usually much smaller than the wavelength of the radiation, allowing the spatial variation of the radiation field's phase to be neglected in the description of transition rates. Somewhat unexpectedly, this approximation, known as the electric dipole approximation, is still valid for the ionization of micrometre-sized atoms in highly excited Rydberg states by laser light with a wavelength of about the same size. Here we employ a standing-wave laser field as a spatially resolving probe within the volume of a Rydberg atom to show that the photoionization process only occurs near the nucleus, within a volume that is small with respect to both the atom and the laser wavelength. This evidence resolves the apparent inconsistency of the electric dipole approximation's validity for photoionization of Rydberg atoms, and it verifies the theory of light-matter interaction in a limiting case. PMID:24336092

  19. Spin Exchange in Rydberg EIT

    NASA Astrophysics Data System (ADS)

    Nicholson, Travis; Thompson, Jeff; Liang, Qiyu; Cantu, Sergio; Venkatramani, Aditya; Pohl, Thomas; Choi, Soonwon; Lukin, Mikhail; Vuletic, Vladan

    2016-05-01

    The realization of strong optical nonlinearities between two photons has been a longstanding goal in quantum science. We achieve large single-photon-level nonlinearities with Rydberg EIT, which combines slow light techniques with strongly interacting Rydberg states. For two Rydberg atoms in the same state, a Van der Waals interaction is the dominant coupling mechanism. Inherently stronger dipole-dipole interactions are also possible between atoms in different Rydberg states. Using light storage and microwave resonances, we study the effect of dipole-dipole interactions in Rydberg EIT. We observe a coherent spin exchange effect for pairs of states dominated by dipole-dipole interactions. Spin exchange manifests as an increase in optical transmission through a cold Rubidium gas that is highly dissipative in the presence of Van der Waals interactions. We also observe a controlled π / 2 phase shift due to this effect, which paves the way for robust, universal all-optical quantum gates.

  20. Universal Nonequilibrium Properties of Dissipative Rydberg Gases

    NASA Astrophysics Data System (ADS)

    Marcuzzi, Matteo; Levi, Emanuele; Diehl, Sebastian; Garrahan, Juan P.; Lesanovsky, Igor

    2014-11-01

    We investigate the out-of-equilibrium behavior of a dissipative gas of Rydberg atoms that features a dynamical transition between two stationary states characterized by different excitation densities. We determine the structure and properties of the phase diagram and identify the universality class of the transition, both for the statics and the dynamics. We show that the proper dynamical order parameter is in fact not the excitation density and find evidence that the dynamical transition is in the "model A " universality class; i.e., it features a nontrivial Z2 symmetry and a dynamics with nonconserved order parameter. This sheds light on some relevant and observable aspects of dynamical transitions in Rydberg gases. In particular it permits a quantitative understanding of a recent experiment [C. Carr, Phys. Rev. Lett. 111, 113901 (2013)] which observed bistable behavior as well as power-law scaling of the relaxation time. The latter emerges not due to critical slowing down in the vicinity of a second order transition, but from the nonequilibrium dynamics near a so-called spinodal line.

  1. Radial Rydberg wavepacket maps

    NASA Astrophysics Data System (ADS)

    Zeibel, J. G.; Jones, R. R.

    2001-04-01

    Picosecond laser pulses have been used to excite radial Rydberg wavepackets in Ca. Time-delayed, unipolar, `half-cycle' electric field pulses are used to probe the evolution of the wavepackets as a continuous function of binding energy. The data provide three-dimensional maps of wavepacket recurrence probability versus binding energy versus time. A rescaling of the energy and time coordinate axes allows the visualization of the distinct difference between the initial oscillations of the wavepacket and those that occur at integer and fractional revivals.

  2. High Rydberg states of DABCO: Spectroscopy, ionization potential, and comparison with mass analyzed threshold ionization

    NASA Astrophysics Data System (ADS)

    Boogaarts, Maarten G. H.; Holleman, Iwan; Jongma, Rienk T.; Parker, David H.; Meijer, Gerard; Even, Uzi

    1996-03-01

    Doubly-resonant excitation/vibrational autoionization is used to accurately determine the ionization potential (IP) of the highly symmetric caged amine 1,4 diazabicyclo[2,2,2]octane (DABCO). The IP of DABCO excited with one quantum of the ν24(e') vibration lies at (59 048.62±0.03) cm-1, based on fitting 56 components of the npxy Rydberg series (δ=0.406±0.002) to the Rydberg formula. Rydberg state transition energies and linewidths are determined using standard calibration and linefitting techniques. The IP determined from Rydberg state extrapolation is compared with that determined by mass analyzed threshold ionization (MATI). Effects of static electric fields on MATI signals measured for the high Rydberg states are discussed.

  3. Electromagnetically induced transparency with Rydberg atoms inside a high-finesse optical cavity

    NASA Astrophysics Data System (ADS)

    Sheng, Jiteng; Kumar, Santosh; Sedlacek, Jonathon; Chao, Yuanxi; Fan, Haoquan; Shaffer, James

    2016-05-01

    We present experimental work on the observation of Rydberg electromagnetically induced transparency (EIT) inside a high-finesse optical cavity. We show that a cold atomic cloud with controllable number of atoms can be transported into the cavity by using a focus-tunable lens. Rydberg atoms are excited via a two-photon transition in a ladder-type EIT configuration. A three-peak structure in the cavity transmission can be observed when Rydberg EIT atoms are generated inside the cavity. The two side peaks are caused by ``bright state polaritons'', while the central peak corresponds to a ``dark-state polariton'' The cavity Rydberg EIT system can be useful for single photon generation using the Rydberg blockade effect, studying many-body physics, and generating novel quantum states amongst many other applications. This work is supported by AFOSR.

  4. Deexcitation of high-Rydberg-state atoms with a chirped train of half-cycle pulses

    SciTech Connect

    Kopyciuk, T.; Parzynski, R.

    2007-05-15

    Encouraged by the experiments on production of antihydrogen atoms in high Rydberg states we have calculated the effect of deexcitation towards lower states by a chirped train of identical unidirectional half-cycle pulses. The calculations exploit both the one-dimensional and impulse approximations providing convenient analytical formulas for the Rydberg-to-Rydberg transition amplitudes. The calculated deexcitation is shown in terms of the mean value of localization of the Rydberg wave packet in the coordinate space, the Rydberg-state population distribution, the Husimi phase-space distribution function, and the probability density distribution, each of these measures vs the length of the applied train of half-cycle pulses. The results for chirped trains are compared with those for periodic trains and examples of higher deexcitation efficiency of the chirped trains are given.

  5. Coherent excitation of a single atom to a Rydberg state

    SciTech Connect

    Miroshnychenko, Y.; Gaeetan, A.; Evellin, C.; Grangier, P.; Wilk, T.; Browaeys, A.; Comparat, D.; Pillet, P.

    2010-07-15

    We present the coherent excitation of a single Rubidium atom to the Rydberg state 58d{sub 3/2} using a two-photon transition. The experimental setup is described in detail, as are experimental techniques and procedures. The coherence of the excitation is revealed by observing Rabi oscillations between ground and Rydberg states of the atom. We analyze the observed oscillations in detail and compare them to numerical simulations which include imperfections of our experimental system. Strategies for future improvements on the coherent manipulation of a single atom in our settings are given.

  6. Systematics of Rydberg Series of Diatomic Molecules and Correlation Diagrams

    NASA Astrophysics Data System (ADS)

    Lee, Chun-Woo

    2015-06-01

    Rydberg states are studied for H2, Li2, HeH, LiH and BeH using the multi-reference configuration interaction (MRCI) method. The systematics and regularities of the physical properties such as potential energies curves (PECs), quantum defect curves, permanent dipole moment and transition dipole moment curves of the Rydberg series are studied. They are explained using united atom perturbation theory by Bingel and Byers-Brown, Fermi model, Stark theory, and Mulliken's theory. Interesting mirror relationships of the dipole moments are observed between l-mixed Rydberg series, indicating that the members of the l-mixed Rydberg series have dipole moments with opposite directions, which are related to the reversal of the polarity of a dipole moment at the avoided crossing points. The assignment of highly excited states is difficult because of the usual absence of the knowledge on the behaviors of potential energy curves at small internuclear separation whereby the correlation between the united atom limit and separated atoms limit cannot be given. All electron MRCI calculations of PECs are performed to obtain the correlation diagrams between Rydberg orbitals at the united-atom and separated atoms limits.

  7. Rydberg-induced optical nonlinearities from a cold atomic ensemble trapped inside a cavity

    NASA Astrophysics Data System (ADS)

    Boddeda, R.; Usmani, I.; Bimbard, E.; Grankin, A.; Ourjoumtsev, A.; Brion, E.; Grangier, P.

    2016-04-01

    We experimentally characterize the optical nonlinear response of a cold atomic medium placed inside an optical cavity, and excited to Rydberg states. The excitation to S and D Rydberg levels is carried out via a two-photon transition in an electromagnetically induced transparency configuration, with a weak (red) probe beam on the lower transition, and a strong (blue) coupling beam on the upper transition. The observed optical nonlinearities induced by S states for the probe beam can be explained using a semi-classical model with van der Waals’ interactions. For the D states, it appears necessary to take into account a dynamical decay of Rydberg excitations into a long-lived dark state. We show that the measured nonlinearities can be explained by using a Rydberg bubble model with a dynamical decay.

  8. Study of Rydberg blockade mediated optical non-linearity in thermal vapor

    NASA Astrophysics Data System (ADS)

    Bhowmick, Arup; Mohapatra, Ashok

    We demonstrate Rydberg blockade by coupling to Rydberg state via two-photon excitation in rubidium thermal vapor. The probe beam coupling to the D 2 transition was blue detuned by 1 . 3 GHz and a coupling beam was scanned to excite the atoms to Rydberg state via two-photon transition (5s1/2 ⟶ n s1/2). The dispersion of the probe beam is modified due to the 2-photon excitation and is measured using an optical heterodyne detection technique in the experiment. We have observed that the dispersion of the probe beam depends linearly on atomic vapor density while coupling to a Rydberg state with principal quantum number, n = 30 . However, density dependent suppression of the dispersion is observed while coupling to the Rydberg state with n = 60 . Since the dispersion of the probe beam due to 2-photon excitation depends on the Rydberg population, the density dependent suppression is explained by introducing the concept of blockade. The blockade radius is measured to be about 2.2 μm which is consistent with the scaling due to Doppler width of the 2-photon resonance in thermal vapor. Our result promises the realization of single photon source and strong single photon non-linearity based on Rydberg blockade in thermal vapor. National Institute of Science Education and Research.

  9. Electrostatically Guided Rydberg Positronium.

    PubMed

    Deller, A; Alonso, A M; Cooper, B S; Hogan, S D; Cassidy, D B

    2016-08-12

    We report experiments in which positronium (Ps) atoms were guided using inhomogeneous electric fields. Ps atoms in Rydberg-Stark states with principal quantum number n=10 and electric dipole moments up to 610 D were prepared via two-color two-photon optical excitation in the presence of a 670  V cm^{-1} electric field. The Ps atoms were created at the entrance of a 0.4 m long electrostatic quadrupole guide, and were detected at the end of the guide via annihilation gamma radiation. When the lasers were tuned to excite low-field-seeking Stark states, a fivefold increase in the number of atoms reaching the end of the guide was observed, whereas no signal was detected when high-field-seeking states were produced. The data are consistent with the calculated geometrical guide acceptance. PMID:27563960

  10. Electrostatically Guided Rydberg Positronium

    NASA Astrophysics Data System (ADS)

    Deller, A.; Alonso, A. M.; Cooper, B. S.; Hogan, S. D.; Cassidy, D. B.

    2016-08-01

    We report experiments in which positronium (Ps) atoms were guided using inhomogeneous electric fields. Ps atoms in Rydberg-Stark states with principal quantum number n =10 and electric dipole moments up to 610 D were prepared via two-color two-photon optical excitation in the presence of a 670 V cm-1 electric field. The Ps atoms were created at the entrance of a 0.4 m long electrostatic quadrupole guide, and were detected at the end of the guide via annihilation gamma radiation. When the lasers were tuned to excite low-field-seeking Stark states, a fivefold increase in the number of atoms reaching the end of the guide was observed, whereas no signal was detected when high-field-seeking states were produced. The data are consistent with the calculated geometrical guide acceptance.

  11. Gravitational-wave phasing for low-eccentricity inspiralling compact binaries to 3PN order

    NASA Astrophysics Data System (ADS)

    Moore, Blake; Favata, Marc; Arun, K. G.; Mishra, Chandra Kant

    2016-06-01

    Although gravitational radiation causes inspiralling compact binaries to circularize, a variety of astrophysical scenarios suggest that binaries might have small but non-negligible orbital eccentricities when they enter the low-frequency bands of ground- and space-based gravitational-wave detectors. If not accounted for, even a small orbital eccentricity can cause a potentially significant systematic error in the mass parameters of an inspiralling binary [M. Favata, Phys. Rev. Lett. 112, 101101 (2014)]. Gravitational-wave search templates typically rely on the quasicircular approximation, which provides relatively simple expressions for the gravitational-wave phase to 3.5 post-Newtonian (PN) order. Damour, Gopakumar, Iyer, and others have developed an elegant but complex quasi-Keplerian formalism for describing the post-Newtonian corrections to the orbits and waveforms of inspiralling binaries with any eccentricity. Here, we specialize the quasi-Keplerian formalism to binaries with low eccentricity. In this limit, the nonperiodic contribution to the gravitational-wave phasing can be expressed explicitly as simple functions of frequency or time, with little additional complexity beyond the well-known formulas for circular binaries. These eccentric phase corrections are computed to 3PN order and to leading order in the eccentricity for the standard PN approximants. For a variety of systems, these eccentricity corrections cause significant corrections to the number of gravitational-wave cycles that sweep through a detector's frequency band. This is evaluated using several measures, including a modification of the useful cycles. By comparing to numerical solutions valid for any eccentricity, we find that our analytic solutions are valid up to e0≲0.1 for comparable-mass systems, where e0 is the eccentricity when the source enters the detector band. We also evaluate the role of periodic terms that enter the phasing and discuss how they can be incorporated into some of

  12. Rydberg States of Atoms and Molecules

    NASA Astrophysics Data System (ADS)

    Stebbings, R. F.; Dunning, F. B.

    2011-03-01

    List of contributors; Preface; 1. Rydberg atoms in astrophysics A. Dalgarno; 2. Theoretical studies of hydrogen Rydberg atoms in electric fields R. J. Damburg and V. V. Kolosov; 3. Rydberg atoms in strong fields D. Kleppner, Michael G. Littman and Myron L. Zimmerman; 4. Spectroscopy of one- and two-electron Rydberg atoms C. Fabre and S. Haroche; 5. Interaction of Rydberg atoms with blackbody radiation T. F. Gallagher; 6. Theoretical approaches to low-energy collisions of Rydberg atoms with atoms and ions A. P. Hickman, R. E. Olson and J. Pascale; 7. Experimental studies of the interaction of Rydberg atoms with atomic species at thermal energies F. Gounand and J. Berlande; 8. Theoretical studies of collisions of Rydberg atoms with molecules Michio Matsuzawa; 9. Experimental studies of thermal-energy collisions of Rydberg atoms with molecules F. B. Dunning and R. F. Stebbings; 10. High-Rydberg molecules Robert S. Freund; 11. Theory of Rydberg collisions with electrons, ions and neutrals M. R. Flannery; 12. Experimental studies of the interactions of Rydberg atoms with charged particles J. -F. Delpech; 13. Rydberg studies using fast beams Peter M. Koch; Index.

  13. Ultralong-range Molecules in Strontium Rydberg Gases

    NASA Astrophysics Data System (ADS)

    Killian, Thomas

    2016-05-01

    Alkaline-earth metal atoms are attracting increased attention for studies of ultracold Rydberg gases because of new opportunities created by strong core transitions accessible with visible light and the presence of excited triplet states. We have created and characterized ultralong-range Sr2 molecules formed from one ground-state 5 s21 S0 atom and one atom in a 5sns 3 S1 Rydberg state. Molecules are formed in a trapped ultracold atomic gas using two-photon excitation, near resonance with the 5s5p 3 P1 intermediate state. Spectra for both a thermal gas and a Bose-Einstein condensate have been studied, and highly structured vibrational spectra are obtained for molecular dimers, trimers, and tetramers. Measured lifetimes of Rydberg atoms and molecules in dense gases of ground state atoms show that, in marked contrast to earlier measurements involving rubidium Rydberg molecules, the lifetimes of the low-lying molecular vibrational states are very similar to those of the parent Rydberg atoms. This reflects the fact that in strontium there is no p-wave resonance for electron scattering in this energy regime, unlike the situation in rubidium. The absence of a resonance offers advantages for experiments involving strontium Rydberg atoms as impurities in quantum gases and for testing theories of molecular formation and decay. Research supported by the AFOSR under Grant No. FA9550-14-1-0007, the NSF under Grants No. 1301773 and No. 1205946, and the Robert A, Welch Foundation under Grants No. C-0734 and No. C-1844.

  14. Photoassociation of long-range nD Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Raithel, Georg

    2015-05-01

    Cold atomic systems have opened new frontiers at the interface of atomic and molecular physics. Of particular interest are a recently discovered class of long-range, homonuclear Rydberg molecules first predicted in and observed in. In rubidium, these molecules are formed via low-energy electron scattering of the Rydberg electron from a 5S1/2 ground-state atom that is present within the Rydberg atom's volume. The binding mostly arises from S-wave and P-wave triplet scattering. In recent work, we have observed long-range homonuclear diatomic nD Rydberg molecules photoassociated out of an ultracold gas of 87Rb atoms for principal quantum numbers 34 <= n <= 40. Related results have also been reported in. The measured ground-state binding energies of 87Rb(nD + 5S1 / 2) molecular states are larger than those of their 87Rb(nS + 5S1 / 2) counterparts, showing the dependence of the molecular bond on the angular momentum of the Rydberg atom. We have exhibited the transition of 87Rb(nD + 5S1 / 2) molecules from a molecular-binding-dominant regime at low n to a fine-structure-dominant regime at high n [akin to Hund's cases (a) and (c), respectively]. In our analysis, we use a Fermi model that includes S-wave and P-wave singlet and triplet scattering, the fine structure coupling of the Rydberg atom and the hyperfine structure coupling of the 5S1/2 atom. The hyperfine structure is important because it gives rise to mixed singlet-triplet potentials. This work was supported by the AFOSR (FA9550-10-1-0453) and the NSF (PHY-1205559).

  15. Quantum interface between Rydberg ensembles and mechanical oscillators in free space

    NASA Astrophysics Data System (ADS)

    Bariani, Francesco; Otterbach, Johannes; Tan, Huatang; Buchmann, L. F.; Meystre, Pierre

    2013-05-01

    We analyze theoretically an electro-mechanical interface between a charged mechanical oscillator and an ensemble of Rydberg atoms. The charged mechanical oscillator acting as an oscillating electric dipole is coupled to the large electric dipole of the Rydberg transition. The Rydberg blockade effect guarantees that only a single collective spin wave is excited in the atomic ensemble. This hybrid system allows for quantum control of the state of one or more mechanical oscillators. The rich atomic Rydberg spectrum and high level of control of atomic transitions allow to build feedback protocols that maximize its fidelity. We also comment on the use of this interface for phononic state tomography. We ackowledge financial support from NSF, ARO and the DARPA QuaSAR and ORCHID programs.

  16. Rydberg atoms in ultracold plasmas

    NASA Astrophysics Data System (ADS)

    Rolston, Steven

    2009-05-01

    Ultracold plasmas are formed through the photoionization of laser-cooled atoms, or spontaneous ionization of a dense cloud of Rydberg atoms or now molecules[1]. Ultracold plasmas are inherently metastable, as the ions and electrons would be in a lower energy state bound together as atoms. The dominant process of atom formation in these plasmas is three-body recombination, a collision between two electrons and an ion that leads to the formation of a Rydberg atom. This collisional process is not only important in determining the lifetime and density of the plasma, but is also critical in determining the time evolution of the temperature. The formation of the Rydberg atoms is accompanied by an increase in electron energy for the extra electron in the collision, and is a source of heating in these plasmas. Classical three-body recombination theory scales as T-9/2, and thus as a plasma cools due to a process such as adiabatic expansion, recombination-induced heating turns on, limiting the temperature [2]. The Rydberg atoms formed live in the plasma and contribute to the temperature dynamics, as collisions with plasma electrons can change the principal quantum number of the Rydberg atom, driving it to more tightly bound states (a source of plasma heating) or to higher states (a source of plasma cooling). If the plasma is cold and dense enough to be strongly coupled, classical three-body recombination theory breaks down. Recent theoretical work [3] suggests that the rate limits as the plasma gets strongly coupled. I will review the role of Rydberg atoms in ultracold plasmas and prospects for probing Rydberg collisions in the strongly coupled environment. [4pt] [1] J. P. Morrison, et al., Phys. Rev. Lett. 101, 205005 (2008 [0pt] [2] R. S. Fletcher, X. Zhang, and S. L. Rolston, Phys. Rev. Lett. 99, 145001 (2007 [0pt] [3] T. Pohl, private communication.

  17. Polarization Measurements of the Resonant Multiphoton Ionization Spectrum of the 3 s Rydberg States of Monomethylpyridines

    NASA Astrophysics Data System (ADS)

    Kosmidis, C.; Bolovinos, A.; Tsekeris, P.

    1993-07-01

    The circular to linear polarization ratio for the two-photon excitation of the 3 s Rydberg states of monomethylpyridines has been measured by 2 + 1 resonant MPI spectroscopy in a static cell. The symmetry of the Rydberg vibrational bands is deduced and the results from the 0-0 transition suggest that the highest occupied MO of 4-methylpyridine is an n MO, while that for 2- and 3-methylpyridines is a π-type one.

  18. Experimental demonstration of Rydberg dressing in a many-body system

    NASA Astrophysics Data System (ADS)

    Zeiher, Johannes; Schauss, Peter; Hild, Sebastian; Rubio-Abadal, Antonio; Choi, Jae-Yoon; van Bijnen, Rick; Pohl, Thomas; Bloch, Immanuel; Gross, Christian

    2016-05-01

    Rydberg atoms offer the possibility to study long range interacting systems of ultracold atoms due to their strong van der Waals interactions. Admixture of a Rydberg state to a ground state, known as Rydberg dressing, allows for increased experimental tunability of these interactions and promises to study novel phases of matter. Here we report on our results of the realization of Rydberg dressing in a many-body spin system. Starting from a two-dimensional spin-polarized Mott insulator of an ultracold gas of rubidium-87, we optically couple one spin component to a Rydberg p-state on a single photon ultra-violet transition at 297 nm. Using microwave Ramsey interferometry in the ground state manifold, we measure the spin-spin correlations emerging due to the admixture of long range interactions to the ground state. To show the predicted versatility of Rydberg dressing, we tune the range and anisotropy of the interaction. We furthermore discuss loss processes affecting our dressed ensembles and present initial indications of improved lifetimes in our system. Our results constitute an important step towards the realization of novel spin models with Rydberg dressed interactions.

  19. Microwave electric field sensing with Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Stack, Daniel T.; Kunz, Paul D.; Meyer, David H.; Solmeyer, Neal

    2016-05-01

    Atoms form the basis of precise measurement for many quantities (time, acceleration, rotation, magnetic field, etc.). Measurements of microwave frequency electric fields by traditional methods (i.e. engineered antennas) have limited sensitivity and can be difficult to calibrate properly. Highly-excited (Rydberg) neutral atoms have very large electric-dipole moments and many dipole allowed transitions in the range of 1 - 500 GHz. It is possible to sensitively probe the electric field in this range using the combination of two quantum interference phenomena: electromagnetically induced transparency and the Autler-Townes effect. This technique allows for very sensitive field amplitude, polarization, and sub-wavelength imaging measurements. These quantities can be extracted by measuring properties of a probe laser beam as it passes through a warm rubidium vapor cell. Thus far, Rydberg microwave electrometry has relied upon the absorption of the probe laser. We report on our use of polarization rotation, which corresponds to the real part of the susceptibility, for measuring the properties of microwave frequency electric fields. Our simulations show that when a magnetic field is present and directed along the optical propagation direction a polarization rotation signal exists and can be used for microwave electrometry. One central advantage in using the polarization rotation signal rather than the absorption signal is that common mode laser noise is naturally eliminated leading to a potentially dramatic increase in signal-to-noise ratio.

  20. Ultralong-range polyatomic Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Gonzalez-Ferez, Rosario

    2016-05-01

    Ultralong-range polyatomic Rydberg molecules are formed when a ground-state atom is bound to a Rydberg atom. The binding mechanism of these Rydberg molecules is based on the low-energy collisions between a Rydberg electron and a ground-state atom and leads to the unusual oscillatory behavior of the adiabatic potential energy curves. If the ground-state atom immersed into the Rydberg wave function is replaced by a heteronuclear diatomic molecule another type of polyatomic Rydberg molecules can form. In this case, the Rydberg electron is coupled to the internal states of the polar ground-state molecule. In this talk, we will explore the electronic structure and rovibrational properties of these ultralong-range polyatomic Rydberg molecule. For the second type of Rydberg molecules, the polar dimer is allowed to rotate in the electric fields generated by the Rydberg electron and Rydberg core as well as an additional external field. We will investigate the metamorphosis of the Born-Oppenheimer potential curves, essential for the binding mechanism, with varying electric field and analyze the resulting properties such as the vibrational structure and the alignment and orientation of the polar dimer.

  1. Absence of collective decay in a cold Rydberg gas

    NASA Astrophysics Data System (ADS)

    Zhou, Tao; Richards, B. G.; Jones, R. R.

    2016-03-01

    We have studied the decay of Rydberg excitations in a cold Rb gas. A 10 ns, pulsed-dye-amplified diode laser excites Rb atoms at 70 μ K in a magneto-optical trap to n s or n p Rydberg states with principal quantum numbers 26 ≤n ≤40 . Time-delayed state-selective field ionization is used to directly monitor the population in the initial and neighboring Rydberg levels. The measured time dependence of the Rydberg population is well described by numerical simulations which consider only spontaneous emission and population transfer by blackbody radiation. No evidence for collective decay is found at atom densities up to 3 ×109cm-3 . This result is in contrast to a previous study [Wang et al., Phys. Rev. A 75, 033802 (2007), 10.1103/PhysRevA.75.033802], in which superradiant decay was theoretically predicted and experimentally inferred for atom density and laser focal volume conditions very similar to those considered here. Suppression of collective emission is likely due to variations in transition energies within the atom sample, dominated by inhomogeneities in dipole-dipole exchange interactions for initial s states, or by a combination of dipole-dipole and electric field inhomogeneities for the initial p states.

  2. Static and dynamic polarizability for C2+ in Rydberg states

    NASA Astrophysics Data System (ADS)

    Stancalie, V.

    2015-07-01

    This work presents results from a non-perturbative calculation of dynamic polarizability of C III ions in 1s22sns (1Se) Rydberg states. We employ a two-state model for dressed atomic states to investigate the effect of the frequency-dependent polarizability of optically dressed 1s22sns(1Se) states (n = 5 - 12) on transitions to nearby states (1s22pns(1P1o)). Our model calculation results indicate that the resonance structure of the polarizabilities is entirely captured by the transition terms whereas the free electron polarizability only provides a smooth background. The resonance structure is evident in the plots and the widths increase with increasing principal quantum number. This work refers to highly excited 1s22sns (1S) Rydberg states, embedded in the electric dipole field of the 2s - 2p core transition in Li-like C3+ ion. The contributions of the individual transitions to the static polarizabilities of these Rydberg states are obtained from the use of the sum-over-state method. To this aim, both the C2+ ground state and the C3+ target state energies have been carefully calculated based on the configuration interactions method implemented in the General-purpose Relativistic Atomic Structure Package. Agreement is reasonably good with existing data wherever available. These results are believed to be the first such values for this system and will be important for ionic spectroscopy and plasma diagnostics.

  3. Laser frequency locking based on Rydberg electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Yuechun, Jiao; Jingkui, Li; Limei, Wang; Hao, Zhang; Linjie, Zhang; Jianming, Zhao; Suotang, Jia

    2016-05-01

    We present a laser frequency locking to Rydberg transition with electromagnetically induced transparency (EIT) spectra in a room-temperature cesium vapor cell. Cesium levels 6S1/2, 6P3/2, and the nD5/2 state, compose a cascade three-level system, where a coupling laser drives Rydberg transition, and probe laser detects the EIT signal. The error signal, obtained by demodulating the EIT signal, is used to lock the coupling laser frequency to Rydberg transition. The laser frequency fluctuation, ∼0.7 MHz, is obtained after locking on, with the minimum Allan variance to be 8.9 × 10‑11. This kind of locking method can be used to stabilize the laser frequency to the excited transition. Project supported by the National Basic Research Program of China (Grant No. 2012CB921603), the National Natural Science Foundation of China (Grants Nos. 11274209, 61475090, 61378039, and 61378013), and the Research Project Supported by Shanxi Scholarship Council of China (Grant No. 2014-009).

  4. Oscillator Strengths and Predissociation Rates for Rydberg Transitions in 12C16O, 13C16O, and 13C18O Involving the E 1Π, B 1Σ+, and W 1Π States

    NASA Astrophysics Data System (ADS)

    Eidelsberg, M.; Sheffer, Y.; Federman, S. R.; Lemaire, J. L.; Fillion, J. H.; Rostas, F.; Ruiz, J.

    2006-08-01

    One of the processes controlling the interstellar CO abundance and the ratio of its isotopologues is photodissociation. Accurate oscillator strengths and predissociation rates for Rydberg transitions are needed for modeling this process. We present results on absorption from the E 1Π-X 1Σ+ (1-0) and B 1Σ+-X 1Σ+ (6-0) bands at 1051 and 1002 Å, respectively, and the vibrational progression W 1Π-X 1Σ+ (v'-0) bands with v'=0-3 at 972, 956, 941, and 925 Å, respectively. The corresponding spectra were acquired at the high resolution (R~30,000) SU5 beam line at the Super ACO Synchrotron in Orsay, France. Spectra were obtained for the 12C16O, 13C 16O, and 13C18O isotopologues. These represent the most complete set of measurements available. Comparison is made with earlier results, both empirical and theoretical. While earlier determinations of oscillator strengths based on absorption from synchrotron radiation tend to be somewhat smaller than ours, the suite of measurements from a variety of techniques agree for the most part, considering the mutual uncertainties. For the bands studied here, their relative weakness, or their significant line widths arising from predissociation, minimizes potential problems from large optical depths at line center in absorption measurements. Predissociating line widths could generally be extracted from the spectra thanks to the profile simulations used in the analysis. In many cases, these simulations allowed us to consider e and f parity levels separately and to determine the dependence of the width on rotational quantum number, J. Our results are consistent with earlier determinations, especially the widths inferred from laser experiments.

  5. Spectroscopic Observation of Resonant Electric Dipole-Dipole Interactions between Cold Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Afrousheh, K.; Bohlouli-Zanjani, P.; Vagale, D.; Mugford, A.; Fedorov, M.; Martin, J. D.

    2004-11-01

    Resonant electric dipole-dipole interactions between cold Rydberg atoms were observed using microwave spectroscopy. Laser-cooled 85Rb atoms in a magneto-optical trap were optically excited to 45d5/2 Rydberg states using a pulsed laser. A microwave pulse transferred a fraction of these Rydberg atoms to the 46p3/2 state. A second microwave pulse then drove atoms in the 45d5/2 state to the 46d5/2 state, and was used as a probe of interatomic interactions. The spectral width of this two-photon probe transition was found to depend on the presence of the 46p3/2 atoms, and is due to the resonant electric dipole-dipole interaction between 45d5/2 and 46p3/2 Rydberg atoms.

  6. Electro-optic control of atom-light interactions using Rydberg dark-state polaritons

    NASA Astrophysics Data System (ADS)

    Bason, M. G.; Mohapatra, A. K.; Weatherill, K. J.; Adams, C. S.

    2008-03-01

    We demonstrate a multiphoton Rydberg dark resonance where a Λ system is coupled to a Rydberg state. This N -type level scheme combines the ability to slow and store light pulses associated with long-lived ground-state superpositions with the strongly interacting character of Rydberg states. For the nd5/2 Rydberg state in R87b (with n=26 or 44) and a beam size of 1 mm, we observe a resonance linewidth of less than 100 kHz in a room-temperature atomic ensemble limited by transit-time broadening. The resonance is switchable with an electric field of order 1Vcm-1 . Applications in electro-optic switching and photonic phase gates are discussed.

  7. Optical Measurements of Strong Microwave Fields with Rydberg Atoms in a Vapor Cell

    NASA Astrophysics Data System (ADS)

    Anderson, D. A.; Miller, S. A.; Raithel, G.; Gordon, J. A.; Butler, M. L.; Holloway, C. L.

    2016-03-01

    We present a spectral analysis of Rydberg atoms in strong microwave fields using electromagnetically induced transparency (EIT) as an all-optical readout. The measured spectroscopic response enables optical, atom-based electric-field measurements of high-power microwaves. In our experiments, microwaves are irradiated into a room-temperature rubidium vapor cell. The microwaves are tuned near the two-photon 65 D -66 D Rydberg transition and reach an electric-field strength of 230 V /m , about 20% of the microwave-ionization threshold of these atoms. A Floquet treatment is used to model the Rydberg-level energies and their excitation rates. We arrive at an empirical model for the field-strength distribution inside the spectroscopic cell that yields excellent overall agreement between the measured and calculated Rydberg EIT-Floquet spectra. Using spectral features in the Floquet maps, we achieve an absolute strong-field measurement precision of 6%.

  8. Cesium Ultra-Long-Range Rydberg Molecules and Many-Body Physics

    NASA Astrophysics Data System (ADS)

    Yang, Jin; Jahangiri, Akbar; Rittenhouse, Seth; Reschke, Margarita; Booth, Donald; Sadeghpour, Hossein; Shaffer, James

    2016-05-01

    Ultra-long-range Rydberg molecules have received increasing interest recently because of their novel properties such as the ability to serve as an electron trap, the potential to possess kilo-Debye dipole moments, and their unique binding mechanism. Recently, experiments focusing on Rydberg P-state and D-state molecules have revealed interesting new features of these novel molecules, like coupling between singlet and triplet scattering channels, p-wave scattering dominated states and their behavior in magnetic fields. In this presentation, we report our recent observation of Cesium D-state ultra-long-range Rydberg molecules and compare our observations to theoretical calculations. We also report our preliminary data on ``polymer'' molecules, which are formed by one Cs Rydberg atom but more than one Cs ground state atom. The transition from a few-body system to a many-body system can provide insight into many-body physics. We acknowledge funding from the NSF.

  9. Resonant quenching of Rydberg atomic states by highly polar molecules

    NASA Astrophysics Data System (ADS)

    Narits, A. A.; Mironchuk, E. S.; Lebedev, V. S.

    2016-06-01

    The results of theoretical studies of the resonant quenching and ion-pair formation processes induced by collisions of Rydberg atoms with highly polar molecules possessing small electron affinities are reported. We elaborate an approach for describing collisional dynamics of both processes and demonstrate the predominant role of resonant quenching channel of reaction for the destruction of Rydberg states by electron-attaching molecules. The approach is based on the solution of the coupled differential equations for the transition amplitudes between the ionic and Rydberg covalent terms of a quasimolecule formed during a collision of particles. It takes into account the possibility of the dipole-bound anion decay in the Coulomb field of the positive ionic core and generalizes previous models of charge-transfer processes involving Rydberg atoms to the cases, when the multistate Landau–Zener approaches become inapplicable. Our calculations for {{Rb}}({nl}) atom perturbed by {{{C}}}2{{{H}}}4{{SO}}3, {{CH}}2{CHCN}, {{CH}}3{{NO}}2, {{CH}}3{CN}, {{{C}}}3{{{H}}}2{{{O}}}3, and {{{C}}}3{{{H}}}4{{{O}}}3 molecules show that the curves representing the dependence of the resonant quenching cross sections on the principal quantum number n are bell-shaped with the positions of maxima being shifted towards lower values of n and the peak values, {σ }{max}({{q})}, several times higher than those for the ion-pair formation, {σ }{max}({{i})}. We obtain a simple power relation between the energy of electron affinity of a molecule and the position of maximum in n-dependence of the resonant quenching cross section. It can be used as an additional means for determining small binding energies of dipole-bound anions from the experimental data on resonant quenching of Rydberg states by highly polar molecules.

  10. Dipole effects in a cold Rydberg gas

    NASA Astrophysics Data System (ADS)

    Han, Jianing

    2009-12-01

    This dissertation is a continuing study of the dipole effects between cold Rydberg atoms in a MOT (Magneto Optical Trap). The dipole-dipole interaction is commonly used to explain the plasma forming process and dipole blockade effects. However, no direct measurements have been made for such interaction. This dissertation is designed to directly measure this interaction and study the effects induced by the dipole interaction. To achieve this, a few experiments were carried out. First, a millimeter wave spectroscopy experiment was performed to determine quantum defects of higher angular momentum f and g states, which then allows us to accurately identify these states. Moreover, the higher angular momentum states play an important role in the plasma forming process. The next experiment examined the oscilloscope trace collected through field ionization pulses on which all our experiments are based, which leads to the conclusion that the side peaks other than the main peak can be due to the field ionization pulse sweeping through the resonances. Based on the knowledge of identifying states obtained from these two experiments, a third experiment was carried out to understand the interactions between cold Rydberg atoms. It was found that the second order dipole-dipole interaction, the van der Waals interaction, commonly exists between the atoms in our atomic sample, and when we excite the atoms from the ns to (n + 1)s states using a narrow band microwave pulse, an asymmetric broadening, which is attributed to the nsns to ns(n + 1) s molecular state transition, was observed. Furthermore, the van der Waals long range molecule is studied, which provides another way to study the two-body to multi-body transition.

  11. Collective state synthesis in an optical cavity using Rydberg atom dipole blockade

    NASA Astrophysics Data System (ADS)

    Kumar, Santosh; Sheng, Jiteng; Sedlacek, Jonathon A.; Fan, Haoquan; Shaffer, James P.

    2016-03-01

    We investigate the coherent manipulation of interacting Rydberg atoms placed inside a high-finesse optical cavity for the deterministic preparation of strongly coupled light-matter systems. We consider a four-level diamond scheme with one common Rydberg level for N interacting atoms. One side of the diamond is used to excite the atoms into a collective ‘superatom’ Rydberg state using either π-pulses or stimulated Raman adiabatic passage (STIRAP) pulses. The upper transition on the other side of the diamond is used to transfer the collective state to one that is coupled to a field mode of an optical cavity. Due to the strong interaction between the atoms in the Rydberg level, the Rydberg blockade mechanism plays a key role in the deterministic quantum state synthesis of the atoms in the cavity. We use numerical simulation to show that non-classical states of light can be generated and that the state that is coupled to the cavity field is a collective one. We also investigate how different decay mechanisms affect this interacting many-body system. We also analyze our system in the case of two Rydberg excitations within the blockade volume. The simulations are carried out with parameters corresponding to realizable high-finesse optical cavities and alkali atoms like rubidium.

  12. Rydberg and π-π* transitions in film surfaces of various kinds of nylons studied by attenuated total reflection far-ultraviolet spectroscopy and quantum chemical calculations: peak shifts in the spectra and their relation to nylon structure and hydrogen bondings.

    PubMed

    Morisawa, Yusuke; Yasunaga, Manaka; Sato, Harumi; Fukuda, Ryoichi; Ehara, Masahiro; Ozaki, Yukihiro

    2014-10-01

    Attenuated total reflection far-ultraviolet (ATR-FUV) spectra in the 145-260 nm region were measured for surfaces (thickness 50-200 nm) of various kinds of nylons in cast films to explore their electronic transitions in the FUV region. ATR-FUV spectra show two major bands near 150 and 200 nm in the surface condensed phase of nylons. Transmittance (Tr) spectra were also observed in particular for the analysis of valence excitations. Time-dependent density functional theory (TD-DFT/CAM-B3LYP) calculations were carried out using the model systems to provide the definitive assignments of their absorption spectra and to elucidate their peak shifts in several nylons, in particular, focusing on their crystal alignment structures and intermolecular hydrogen bondings. Two major bands of nylon films near 150 and 200 nm are characterized as σ-Rydberg 3p and π-π* transitions of nylons, respectively. These assignments are also coherent with those of liquid n-alkanes (n = 5-14) and liquid amides observed previously. The Rydberg transitions are delocalized over the hydrocarbon chains, while the π-π* transitions are relatively localized at the amide group. Differences in the peak positions and intensity were found in both ATR- and Tr-FUV spectra for different nylons. A red-shift of the π-π* amide band in the FUV spectra of nylon-6 and nylon-6/6 models in α-form is attributed to the crystal structure pattern and the intermolecular hydrogen bondings, which result in the different delocalization character of the π-π* transitions and transition dipole coupling. PMID:25203613

  13. Observation of interference effects via four-photon excitation of highly excited Rydberg states in thermal cesium vapor

    NASA Astrophysics Data System (ADS)

    Kondo, Jorge M.; Šibalić, Nikola; Guttridge, Alexander; Wade, Christopher G.; De Melo, Natalia R.; Adams, Charles S.; Weatherill, Kevin J.

    2015-12-01

    We report on the observation of electromagnetically induced transparency (EIT) and absorption (EIA) of highly excited Rydberg states in thermal Cs vapor using a four-step excitation scheme. The advantage of this four-step scheme is that the final transition to the Rydberg state has a large dipole moment and one can achieve similar Rabi frequencies to two- or three-step excitation schemes using two orders of magnitude less laser power. This scheme enables new applications such as dephasing free Rydberg excitation. The observed lineshapes are in good agreement with simulations based on multilevel optical Bloch equations.

  14. Three-photon coherence of Rydberg atomic states

    NASA Astrophysics Data System (ADS)

    Kwak, Hyo Min; Jeong, Taek; Lee, Yoon-Seok; Moon, Han Seb

    2016-05-01

    We investigated three-photon coherence effects of the Rydberg state in a four-level ladder-type atomic system for the 5 S1/2 (F = 3) - 5 P3/2 (F' = 4) - 50 D5/2 - 51 P3/2 transition of 85 Rb atoms. By adding a resonant electric field of microwave (MW) at electromagnetically induced transparency (EIT) in Rydberg state scheme, we observed experimentally that splitting of EIT signal appears under the condition of three-photon resonance in the Doppler-broadened atomic system. Discriminating the two- and three-photon coherence terms from the calculated spectrum in a simple four-level ladder-type Doppler-broadened atomic system, we found that the physical origin of splitting of EIT was three-photon coherence effect, but not three-photon quantum interference phenomena such as three-photon electromagnetically induced absorption (TPEIA).

  15. Millimeter Wave Spectroscopy of Rydberg States of Molecules in the Region of 260-295 GHz

    NASA Astrophysics Data System (ADS)

    Grimes, David; Zhou, Yan; Barnum, Timothy J.; Field, Robert W.

    2015-06-01

    Free induction decay detected chirped pulse millimeter wave spectroscopy of Rydberg-Rydberg transitions in atoms and molecules is a powerful and flexible method for characterizing the electronic structure of Rydberg states and determining the structure and dynamics of the ion-core. Complicating the use of this technique are the difficulties in reliably and repeatedly accessing not just the most information rich core-nonpenetrating states, but also the low-ℓ core-penetrating Rydberg states in the area of principal quantum number n* >35. Small transition moments and narrow linewidths for transitions between valence electronic states and high Rydberg states are the primary limiting factor. We demonstrate a simple method to avoid the problem entirely by using chirped pulse technology operating in the frequency range of 260-295 GHz, which allows us to sample a lower range of n* values than before with comparable frequency resolution and accuracy as our previous W-band experiments. Further improvements to our experiment in order to accurately capture details of Stark demolition, a technique that provides rapid differentiation between core-penetrating and core-nonpenetrating states, will also be discussed.

  16. Theoretical description of electronically excited vinylidene up to 10 eV: first high level ab initio study of singlet valence and Rydberg states.

    PubMed

    Boyé-Péronne, Séverine; Gauyacq, Dolores; Liévin, Jacques

    2014-11-01

    The first quantitative description of the Rydberg and valence singlet electronic states of vinylidene lying in the 0-10 eV region is performed by using large scale ab initio calculations. A deep analysis of Rydberg-valence interactions has been achieved thanks to the comprehensive information contained in the accurate Multi-Reference Configuration Interaction wavefunctions and an original population analysis highlighting the respective role played by orbital and state mixing in such interactions. The present theoretical approach is thus adequate for dealing with larger than diatomic Rydberg systems. The nine lowest singlet valence states have been optimized. Among them, some are involved in strong Rydberg-valence interactions in the region of the Rydberg state equilibrium geometry. The Rydberg states of vinylidene present a great similarity with the acetylene isomer, concerning their quantum defects and Rydberg molecular orbital character. As in acetylene, strong s-d mixing is revealed in the n = 3 s-d supercomplex. Nevertheless, unlike in acetylene, the close-energy of the two vinylidene ionic cores (2)A1 and (2)B1 results into two overlapped Rydberg series. These Rydberg series exhibit local perturbations when an accidental degeneracy occurs between them and results in avoided crossings. In addition, some Δl = 1 (s-p and p-d) mixings arise for some Rydberg states and are rationalized in term of electrostatic interaction from the electric dipole moment of the ionic core. The strongest dipole moment of the (2)B1 cationic state also stabilizes the lowest members of the n = 3 Rydberg series converging to this excited state, as compared to the adjacent series converging toward the (2)A1 ionic ground state. The overall energies of vinylidene Rydberg states lie above their acetylene counterpart. Finally, predictions for optical transitions in singlet vinylidene are suggested for further experimental spectroscopic characterization of vinylidene. PMID:25381524

  17. Theoretical description of electronically excited vinylidene up to 10 eV: First high level ab initio study of singlet valence and Rydberg states

    NASA Astrophysics Data System (ADS)

    Boyé-Péronne, Séverine; Gauyacq, Dolores; Liévin, Jacques

    2014-11-01

    The first quantitative description of the Rydberg and valence singlet electronic states of vinylidene lying in the 0-10 eV region is performed by using large scale ab initio calculations. A deep analysis of Rydberg-valence interactions has been achieved thanks to the comprehensive information contained in the accurate Multi-Reference Configuration Interaction wavefunctions and an original population analysis highlighting the respective role played by orbital and state mixing in such interactions. The present theoretical approach is thus adequate for dealing with larger than diatomic Rydberg systems. The nine lowest singlet valence states have been optimized. Among them, some are involved in strong Rydberg-valence interactions in the region of the Rydberg state equilibrium geometry. The Rydberg states of vinylidene present a great similarity with the acetylene isomer, concerning their quantum defects and Rydberg molecular orbital character. As in acetylene, strong s-d mixing is revealed in the n = 3 s-d supercomplex. Nevertheless, unlike in acetylene, the close-energy of the two vinylidene ionic cores 2A1 and 2B1 results into two overlapped Rydberg series. These Rydberg series exhibit local perturbations when an accidental degeneracy occurs between them and results in avoided crossings. In addition, some Δl = 1 (s-p and p-d) mixings arise for some Rydberg states and are rationalized in term of electrostatic interaction from the electric dipole moment of the ionic core. The strongest dipole moment of the 2B1 cationic state also stabilizes the lowest members of the n = 3 Rydberg series converging to this excited state, as compared to the adjacent series converging toward the 2A1 ionic ground state. The overall energies of vinylidene Rydberg states lie above their acetylene counterpart. Finally, predictions for optical transitions in singlet vinylidene are suggested for further experimental spectroscopic characterization of vinylidene.

  18. Theoretical description of electronically excited vinylidene up to 10 eV: First high level ab initio study of singlet valence and Rydberg states

    SciTech Connect

    Boyé-Péronne, Séverine; Gauyacq, Dolores; Liévin, Jacques

    2014-11-07

    The first quantitative description of the Rydberg and valence singlet electronic states of vinylidene lying in the 0–10 eV region is performed by using large scale ab initio calculations. A deep analysis of Rydberg-valence interactions has been achieved thanks to the comprehensive information contained in the accurate Multi-Reference Configuration Interaction wavefunctions and an original population analysis highlighting the respective role played by orbital and state mixing in such interactions. The present theoretical approach is thus adequate for dealing with larger than diatomic Rydberg systems. The nine lowest singlet valence states have been optimized. Among them, some are involved in strong Rydberg-valence interactions in the region of the Rydberg state equilibrium geometry. The Rydberg states of vinylidene present a great similarity with the acetylene isomer, concerning their quantum defects and Rydberg molecular orbital character. As in acetylene, strong s-d mixing is revealed in the n = 3 s-d supercomplex. Nevertheless, unlike in acetylene, the close-energy of the two vinylidene ionic cores {sup 2}A{sub 1} and {sup 2}B{sub 1} results into two overlapped Rydberg series. These Rydberg series exhibit local perturbations when an accidental degeneracy occurs between them and results in avoided crossings. In addition, some Δl = 1 (s-p and p-d) mixings arise for some Rydberg states and are rationalized in term of electrostatic interaction from the electric dipole moment of the ionic core. The strongest dipole moment of the {sup 2}B{sub 1} cationic state also stabilizes the lowest members of the n = 3 Rydberg series converging to this excited state, as compared to the adjacent series converging toward the {sup 2}A{sub 1} ionic ground state. The overall energies of vinylidene Rydberg states lie above their acetylene counterpart. Finally, predictions for optical transitions in singlet vinylidene are suggested for further experimental spectroscopic

  19. Spectroscopy of acetylene Rydberg states studied by VUV absorption and (3+1)-Resonantly Enhanced Multiphoton Ionisation

    NASA Astrophysics Data System (ADS)

    Boyé, Séverine; Campos, Andrea; Fillion, Jean-Hugues; Douin, Stéphane; Shafizadeh, Niloufar; Gauyacq, Dolores

    2004-03-01

    The ungerade ns+ nd Rydberg states of C 2H 2 converging to the ground state of the C 2H 2+ cation have been investigated in the energy range 74 000- 88 000 cm-1 by (3+1)-multiphoton ionisation (REMPI) and by VUV absorption spectroscopy at the Super-ACO synchrotron radiation facility. Both methods have allowed the selective analysis of the Rydberg transitions with rotational resolution. Mulliken's semi-united atom model, in which predissociation has been taken into account, was used to understand the relative three-photon intensities among the different electronic transitions within the same Rydberg supercomplex. Lifetimes have been evaluated and illustrate very different behaviours towards predissociation for the observed Rydberg states. To cite this article: S. Boyé et al., C. R. Physique 5 (2004).

  20. Long-range quantum gate via Rydberg states of atoms in a thermal microwave cavity

    NASA Astrophysics Data System (ADS)

    Sárkány, Lőrinc; Fortágh, József; Petrosyan, David

    2015-09-01

    We propose an implementation of a universal quantum gate between pairs of spatially separated atoms in a microwave cavity at finite temperature. The gate results from reversible laser excitation of Rydberg states of atoms interacting with each other via exchange of virtual photons through a common cavity mode. Quantum interference of different transition paths between the two-atom ground and double-excited Rydberg states makes both the transition amplitude and resonance largely insensitive to the excitations in the microwave cavity quantum bus which can therefore be in any superposition or mixture of photon number states. Our scheme for attaining ultra-long-range interactions and entanglement also applies to mesoscopic atomic ensembles in the Rydberg blockade regime and is scalable to many ensembles trapped within a centimeter-sized microwave resonator.

  1. Rydberg polaritons in a thermal vapor

    NASA Astrophysics Data System (ADS)

    Ripka, Fabian; Chen, Yi-Hsin; Löw, Robert; Pfau, Tilman

    2016-05-01

    We present a pulsed four-wave mixing scheme via a Rydberg state to create, store, and retrieve collective Rydberg polaritons. The storage medium consists of a gas of thermal Rb atoms confined in a 220 -μ m -thick cell, which is heated above room temperature. The experimental sequence consists of a pulsed excitation of Rydberg polaritons via the D1 line, a variable delay or storage time, and a final retrieval pulse via the D2 line. The lifetime of the Rydberg polaritons is around 1.2 ns, almost entirely limited by the excitation bandwidth and the corresponding motional dephasing of the atoms. The presented scheme combined with a tightly confined atomic ensemble is a good candidate for a deterministic single-photon source, as soon as strong interactions in terms of a Rydberg blockade are added.

  2. Rydberg EIT in High Magnetic Field

    NASA Astrophysics Data System (ADS)

    Ma, Lu; Anderson, David; Miller, Stephanie; Raithel, Georg

    2016-05-01

    We present progress towards an all-optical approach for measurements of strong magnetic fields using electromagnetically induced transparency (EIT) with Rydberg atoms in an atomic vapor. Rydberg EIT spectroscopy is a promising technique for the development of atom-based, calibration- and drift-free technology for high magnetic field sensing. In this effort, Rydberg EIT is employed to spectroscopically investigate the response of Rydberg atoms exposed to strong magnetic fields, in which Rydberg atoms are in the strong-field regime. In our setup, two neodymium block magnets are used to generate fields of about 0.8 Tesla, which strongly perturb the atoms. Information on the field strength and direction is obtained by a comparison of experimental spectra with calculated spectral maps. Investigations of magnetic-field inhomogeneities and other decoherence sources will be discussed.

  3. A Rydberg atom-photon-superconductor quantum interface

    NASA Astrophysics Data System (ADS)

    Isaacs, J. A.; Booth, D. W.; Beck, M. A.; Pritchard, J. D.; Xia, T.; McDermott, R.; Saffman, M.; UW Hybrid QC Collaboration

    2016-05-01

    Hybrid quantum computation bridges disparate quantum technologies in order to achieve fast gates with long coherence times. Our implementation combines superconducting circuit-QED with singly trapped Rydberg atoms. Introducing typical AMO techniques into cryogenic environments required the development of several novel approaches that we will discuss in our talk. Our current experiment involves trapping cesium atoms inside a 4 K cryostat, transporting them first horizontally and then vertically up to a superconducting coplanar waveguide resonator. After transport we use a novel two-photon Rydberg excitation via the 6S1 / 2 --> 5D5 / 2 quadrupole transition to enable direct excitation of nP3 / 2 states for strong electric-dipole coupling to the cavity. This excitation scheme significantly reduces the Doppler mismatch compared to previous two-photon excitation schemes to enable high fidelity operations. First optical spectroscopy and Rabi oscillation results will be shown along with microwave cavity coupling data. Experimental and theoretical efforts toward increasing fidelity of our operations by minimizing sensitivity of the Rydberg atoms to stray external electric fields will be discussed. This work is supported by an ARO DURIP award.

  4. Two body and multibody interaction in a cold Rydberg gas

    NASA Astrophysics Data System (ADS)

    Han, Jianing; Gallagher, Tom

    2009-05-01

    Cold Rydberg atoms trapped in a Magneto Optical Trap (MOT) are not isolated and they tend to bond through dipole-dipole and multiple-multiple interactions between Rydberg atoms. The dipole-dipole interaction and van der Waals interaction between two atoms have been intensively studied. However, the fact that the dipole-dipole interaction and van der Waals interaction show the same size of broadening, studied by Raithel's group, and there is transition between two molecular states, studied by Farooqi and Overstreet, can not be explained by the two atom picture. The purpose of this paper is to show the multibody nature of a dense cold Rydberg gas by studying the molecular state microwave spectrum. Specifically, single body, two body and three body interaction regions are separated. Moreover, the multibody energy levels for selected geometries are calculated. In addition, multibody blockade will be discussed. [3pt] [1] A. Reinhard, K. C. Younge, T. Cubel Liebisch, B. Knuffman, P. R. Berman, and G. Raithel, Phys. Rev. Lett. 100, 233201 (2008).[0pt] [2] S.M. Farooqi, D. Tong, S. Krishnan, J. Stanojevic,Y.P. Zhang, J.R. Ensher, A.S. Estrin, C. Boisseau, R. Cote, E.E. Eyler, and P.L. Gould, Phys. Rev. Lett. 91, 183002 (2003).[0pt] [3] K. Richard Overstreet, Arne Schwettmann, Jonathan Tallant, and James P. Shaffer, Phys. Rev. A 76, 011403 (2007).

  5. An Experimental Apparatus for Studying Rydberg-Rydberg Interactions in Quantum Degenerate Gases of Strontium

    NASA Astrophysics Data System (ADS)

    Camargo, Francisco; Ding, Roger; Aman, James; Zhang, Xinyue; Whalen, Joseph; Fields, Robert; Dunning, F. Barry; Killian, Thomas

    2014-05-01

    We discuss the design and construction of a new apparatus for creating and studying long-range interactions in ultracold gases of strontium by exploiting Rydberg states, either through their direct excitation or through laser-induced Rydberg dressing. Strontium features one fermionic (87Sr) and three bosonic (84Sr, 86Sr, 88Sr) isotopes, all of which have been brought to quantum degeneracy. It also possesses singlet and triplet Rydberg states that furnish a wide variety of attractive and repulsive interactions. Furthermore, strontium Rydberg atoms feature an optically active core electron which can be used to manipulate and detect Rydberg atoms. These features make strontium a promising system for studying interactions in ultracold Rydberg gases. Research supported by Rice University, the NSF, the AFOSR, Shell, and the Robert A. Welch Foundation.

  6. Observation and characterization of cavity Rydberg polaritons

    NASA Astrophysics Data System (ADS)

    Ningyuan, Jia; Georgakopoulos, Alexandros; Ryou, Albert; Schine, Nathan; Sommer, Ariel; Simon, Jonathan

    2016-04-01

    We experimentally demonstrate the emergence of a robust quasiparticle, the cavity Rydberg polariton, when an optical cavity photon hybridizes with a collective Rydberg excitation of a laser-cooled atomic ensemble. Free-space Rydberg polaritons have recently drawn intense interest as tools for quantum information processing and few-body quantum science. Here, we explore the properties of their cavity counterparts in the single-particle sector, observing an enhanced lifetime and slowed dynamics characteristic of cavity dark polaritons. We measure the range of cavity frequencies over which the polaritons persist, corresponding to the spectral width available for polariton quantum dynamics, and the speed limit for quantum information processing. Further, we observe a cavity-induced suppression of inhomogeneous broadening channels and demonstrate the formation of Rydberg polaritons in a multimode cavity. In conjunction with recent demonstrations of Rydberg-induced cavity nonlinearities, our results point the way towards using cavity Rydberg polaritons as a platform for creating high-fidelity photonic quantum materials and, more broadly, indicate that cavity dark polaritons offer enhanced stability and control uniquely suited to optical quantum information processing applications beyond the Rydberg paradigm.

  7. Laser diagnostics of the energy spectrum of Rydberg states of the lithium-7 atom

    SciTech Connect

    Zelener, B. B. Saakyan, S. A.; Sautenkov, V. A.; Manykin, E. A.; Zelener, B. V.; Fortov, V. E.

    2015-12-15

    The spectra of excited lithium-7 atoms prepared in a magneto-optical trap are studied using a UV laser. The laser diagnostics of the energy of Rydberg atoms is developed based on measurements of the change in resonance fluorescence intensity of ultracold atoms as the exciting UV radiation frequency passes through the Rydberg transition frequency. The energies of various nS configurations are obtained in a broad range of the principal quantum number n from 38 to 165. The values of the quantum defect and ionization energy obtained in experiments and predicted theoretically are discussed.

  8. Laser diagnostics of the energy spectrum of Rydberg states of the lithium-7 atom

    NASA Astrophysics Data System (ADS)

    Zelener, B. B.; Saakyan, S. A.; Sautenkov, V. A.; Manykin, E. A.; Zelener, B. V.; Fortov, V. E.

    2015-12-01

    The spectra of excited lithium-7 atoms prepared in a magneto-optical trap are studied using a UV laser. The laser diagnostics of the energy of Rydberg atoms is developed based on measurements of the change in resonance fluorescence intensity of ultracold atoms as the exciting UV radiation frequency passes through the Rydberg transition frequency. The energies of various nS configurations are obtained in a broad range of the principal quantum number n from 38 to 165. The values of the quantum defect and ionization energy obtained in experiments and predicted theoretically are discussed.

  9. Observation of g/u-symmetry mixing in the high-n Rydberg states of HD

    NASA Astrophysics Data System (ADS)

    Sprecher, Daniel; Merkt, Frédéric

    2014-03-01

    The structure and dynamics of high-n Rydberg states belonging to series converging to the (v+ = 0, N+ = 0-2) levels of the X^+ ^2Σ _g^+ electronic ground state of HD+ were studied by high-resolution spectroscopy from the GK ^1Σ _g^+ (v = 1, N = 1) state under field-free conditions. Three effects of g/u-symmetry breaking were detected: (i) Single-photon transitions from the GK (v = 1, N = 1) state of gerade symmetry to the 30d21 and 31g22 Rydberg states of gerade symmetry were observed after careful compensation of the stray electric fields. (ii) The singlet 61p12 Rydberg state of ungerade symmetry was found to autoionize to the N+ = 0, ℓ = 2 ionization continuum of gerade symmetry with a lifetime of 77(10) ns. (iii) Shifts of up to 20 MHz induced by g/u-symmetry mixing were measured for members of the np11 Rydberg series which lie close to nd21 Rydberg states. These observations were analyzed in the framework of multichannel quantum-defect theory. From the observed level shifts, the off-diagonal eigenquantum-defect element μ _pd of singlet-π symmetry was determined to be 0.0023(3) and the corresponding autoionization dynamics could be characterized. The ionization energy of the GK (v = 1, N = 1) state of HD was determined to be 12 710.544 23(10) cm-1.

  10. UV + V UV double-resonance studies of autoionizing Rydberg states of the hydroxyl radical

    NASA Astrophysics Data System (ADS)

    Green, Amy M.; Liu, Fang; Lester, Marsha I.

    2016-05-01

    The hydroxyl radical (OH) is a key oxidant in atmospheric and combustion chemistry. Recently, a sensitive and state-selective ionization method has been developed for detection of the OH radical that utilizes UV excitation on the A2Σ+-X2Π transition followed by fixed 118 nm vacuum ultraviolet (VUV) radiation to access autoionizing Rydberg states [J. M. Beames et al., J. Chem. Phys. 134, 241102 (2011)]. The present study uses tunable VUV radiation generated by four-wave mixing to examine the origin of the enhanced ionization efficiency observed for OH radicals prepared in specific A2Σ+ intermediate levels. The enhancement is shown to arise from resonant excitation to distinct rotational and fine structure levels of two newly identified 2Π Rydberg states with an A3Π cationic core and a 3d electron followed by ionization. Spectroscopic constants are derived and effects due to uncoupling of the Rydberg electron are revealed for the OH 2Π Rydberg states. The linewidths indicate a Rydberg state lifetime due to autoionization on the order of a picosecond.

  11. UV + V UV double-resonance studies of autoionizing Rydberg states of the hydroxyl radical.

    PubMed

    Green, Amy M; Liu, Fang; Lester, Marsha I

    2016-05-14

    The hydroxyl radical (OH) is a key oxidant in atmospheric and combustion chemistry. Recently, a sensitive and state-selective ionization method has been developed for detection of the OH radical that utilizes UV excitation on the A(2)Σ(+)-X(2)Π transition followed by fixed 118 nm vacuum ultraviolet (VUV) radiation to access autoionizing Rydberg states [J. M. Beames et al., J. Chem. Phys. 134, 241102 (2011)]. The present study uses tunable VUV radiation generated by four-wave mixing to examine the origin of the enhanced ionization efficiency observed for OH radicals prepared in specific A(2)Σ(+) intermediate levels. The enhancement is shown to arise from resonant excitation to distinct rotational and fine structure levels of two newly identified (2)Π Rydberg states with an A(3)Π cationic core and a 3d electron followed by ionization. Spectroscopic constants are derived and effects due to uncoupling of the Rydberg electron are revealed for the OH (2)Π Rydberg states. The linewidths indicate a Rydberg state lifetime due to autoionization on the order of a picosecond. PMID:27179488

  12. Van der Waals Interactions and Dipole Blockade in a Cold Rydberg Gas Probed by Microwave Spectroscopy

    NASA Astrophysics Data System (ADS)

    Nguyen, Thanh Long; Celistrino Teixeira, Raul; Hermann Avigliano, Carla; Cantat Moltrecht, Tigrane; Raimond, Jean Michel; Haroche, Serge; Gleyzes, Sebastiens; Brune, Michel

    2016-05-01

    Dipole-dipole interactions between Rydberg atoms are a flourishing tool for quantum information processing and for quantum simulation of complex many-body problems. Microwave spectroscopy of a dense Rydberg gas trapped close to a superconducting atom chip in the strong dipole blockade regime reveals directly the many-body atomic interaction spectrum. We present here a direct measurement of the interaction energy distribution in the strong dipole blockade regime, based on microwave spectroscopy. We first apply this method to the observation of the excitation dynamics of the Rydberg gas, conditioned by dipole-dipole interactions, in either the strong blockade regime or the so-called facilitation regime. We also observe with this method the atomic cloud expansion driven by the repulsive Van der Waals interaction after excitation. This measurement, in good agreement with Monte Carlo simulations of the excitation process and of the cloud dynamics, reveals the limits of the frozen gas approximation. This method can help investigate self-organization and dynamical phase transitions in Rydberg-atom based quantum simulators. This study thus opens a promising route for quantum simulation of many-body systems and quantum information transport in chains of strongly interacting Rydberg atom.

  13. Three-body physics of Rydberg polaritons

    NASA Astrophysics Data System (ADS)

    Wang, Yidan; Gorshkov, Alexey; Qi, Ran; Gullans, Michael; Maghrebi, Mohammad

    2016-05-01

    Under the conditions electromagnetically induced transparency in Rydberg media, slow-light polaritons interact strongly via Rydberg states. While two such polaritons can interact attractively and form two-body bound states, three polariton physics remains largely unexplored. We show that while exact three-polariton bound states do not exist, metastable ones do. The understanding of three-polariton physics will allow for the construction of more precise low energy many-body theories of Rydberg polaritons and may enable the realization of novel exotic equilibrium and out-of equilibrium phenomena with interacting light.

  14. Measurement of Rydberg positronium fluorescence lifetimes

    NASA Astrophysics Data System (ADS)

    Deller, A.; Alonso, A. M.; Cooper, B. S.; Hogan, S. D.; Cassidy, D. B.

    2016-06-01

    We report measurements of the fluorescence lifetimes of positronium (Ps) atoms with principal quantum numbers n =10 -19 . Ps atoms in Rydberg-Stark states were produced via a two-color two-step 1 3S→2 3P→n 3S/n Rydberg levels, yielding values ranging from 3 μ s to 26 μ s . Our data are in accord with the expected radiative lifetimes of Rydberg-Stark states of Ps.

  15. Large energy superpositions via Rydberg dressing

    NASA Astrophysics Data System (ADS)

    Khazali, Mohammadsadegh; Lau, Hon Wai; Humeniuk, Adam; Simon, Christoph

    2016-08-01

    We propose to create superposition states of over 100 strontium atoms in a ground state or metastable optical clock state using the Kerr-type interaction due to Rydberg state dressing in an optical lattice. The two components of the superposition can differ by an order of 300 eV in energy, allowing tests of energy decoherence models with greatly improved sensitivity. We take into account the effects of higher-order nonlinearities, spatial inhomogeneity of the interaction, decay from the Rydberg state, collective many-body decoherence, atomic motion, molecular formation, and diminishing Rydberg level separation for increasing principal number.

  16. Evidence for strong van der Waals type Rydberg-Rydberg interaction in a thermal vapor.

    PubMed

    Baluktsian, T; Huber, B; Löw, R; Pfau, T

    2013-03-22

    We present evidence for Rydberg-Rydberg interaction in a gas of rubidium atoms above room temperature. Rabi oscillations on the nanosecond time scale to different Rydberg states are investigated in a vapor cell experiment. Analyzing the atomic time evolution and comparing to a dephasing model, we find a scaling with the Rydberg quantum number n that is consistent with van der Waals interaction. Our results show that the interaction strength can be larger than the kinetic energy scale (Doppler width), which is the requirement for realization of thermal quantum devices in the GHz regime. PMID:25166800

  17. Electric field sensing near the surface microstructure of an atom chip using cold Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Martin, J. D. D.

    2013-05-01

    Rydberg atoms may enable hybrid systems that combine the benefits of gas-phase atoms with those of solid-state devices. However, these hybrid systems will require atoms to be located near a heterogeneous surface with exposed metal electrodes and dielectric insulators, which are sources of uncontrollable and unwanted electric fields. With this motivation, we have measured the electric fields near the heterogeneous metal-dielectric surface of an atom chip using cold Rydberg atoms. We have also developed a technique for reducing the influence of dc and low-frequency electric fields on Rydberg atom transitions, while retaining their sensitivity to high-frequency resonant fields. Work performed in collaboration with J. D. Carter, L. A. Jones, and O. Cherry and supported by NSERC.

  18. Studies of singlet Rydberg series of LiH derived from Li(nl) + H(1s), with n ≤ 6 and l ≤ 4.

    PubMed

    Gim, Yeongrok; Lee, Chun-Woo

    2014-10-14

    The 50 singlet states of LiH composed of 49 Rydberg states and one non-Rydberg ionic state derivable from Li(nl) + H(1s), with n ≤ 6 and l ≤ 4, are studied using the multi-reference configuration interaction method combined with the Stuttgart/Köln group's effective core potential/core polarization potential method. Basis functions that can yield energy levels up to the 6g orbital of Li have been developed, and they are used with a huge number of universal Kaufmann basis functions for Rydberg states. The systematics and regularities of the physical properties such as potential energies, quantum defects, permanent dipole moments, transition dipole moments, and nonadiabatic coupling matrix elements of the Rydberg series are studied. The behaviors of potential energy curves and quantum defect curves are explained using the Fermi approximation. The permanent dipole moments of the Rydberg series reveal that they are determined by the sizes of the Rydberg orbitals, which are proportional to n(2). Interesting mirror relationships of the dipole moments are observed between l-mixed Rydberg series, with the rule Δl = ±1, except for s-d mixing, which is also accompanied by n-mixing. The members of the l-mixed Rydberg series have dipole moments with opposite directions. The first derivatives of the dipole moment curves, which show the charge-transfer component, clearly show not only mirror relationships in terms of direction but also oscillations. The transition dipole moment matrix elements of the Rydberg series are determined by the small-r region, with two consequences. One is that the transition dipole moment matrix elements show n(-3/2) dependence. The other is that the magnitudes of the transition dipole moment matrix elements decrease rapidly as l increases. PMID:25318728

  19. Studies of singlet Rydberg series of LiH derived from Li(nl) + H(1s), with n ≤ 6 and l ≤ 4

    NASA Astrophysics Data System (ADS)

    Gim, Yeongrok; Lee, Chun-Woo

    2014-10-01

    The 50 singlet states of LiH composed of 49 Rydberg states and one non-Rydberg ionic state derivable from Li(nl) + H(1s), with n ≤ 6 and l ≤ 4, are studied using the multi-reference configuration interaction method combined with the Stuttgart/Köln group's effective core potential/core polarization potential method. Basis functions that can yield energy levels up to the 6g orbital of Li have been developed, and they are used with a huge number of universal Kaufmann basis functions for Rydberg states. The systematics and regularities of the physical properties such as potential energies, quantum defects, permanent dipole moments, transition dipole moments, and nonadiabatic coupling matrix elements of the Rydberg series are studied. The behaviors of potential energy curves and quantum defect curves are explained using the Fermi approximation. The permanent dipole moments of the Rydberg series reveal that they are determined by the sizes of the Rydberg orbitals, which are proportional to n2. Interesting mirror relationships of the dipole moments are observed between l-mixed Rydberg series, with the rule Δl = ±1, except for s-d mixing, which is also accompanied by n-mixing. The members of the l-mixed Rydberg series have dipole moments with opposite directions. The first derivatives of the dipole moment curves, which show the charge-transfer component, clearly show not only mirror relationships in terms of direction but also oscillations. The transition dipole moment matrix elements of the Rydberg series are determined by the small-r region, with two consequences. One is that the transition dipole moment matrix elements show n-3/2 dependence. The other is that the magnitudes of the transition dipole moment matrix elements decrease rapidly as l increases.

  20. Studies of singlet Rydberg series of LiH derived from Li(nl) + H(1s), with n ≤ 6 and l ≤ 4

    SciTech Connect

    Gim, Yeongrok; Lee, Chun-Woo

    2014-10-14

    The 50 singlet states of LiH composed of 49 Rydberg states and one non-Rydberg ionic state derivable from Li(nl) + H(1s), with n ≤ 6 and l ≤ 4, are studied using the multi-reference configuration interaction method combined with the Stuttgart/Köln group's effective core potential/core polarization potential method. Basis functions that can yield energy levels up to the 6g orbital of Li have been developed, and they are used with a huge number of universal Kaufmann basis functions for Rydberg states. The systematics and regularities of the physical properties such as potential energies, quantum defects, permanent dipole moments, transition dipole moments, and nonadiabatic coupling matrix elements of the Rydberg series are studied. The behaviors of potential energy curves and quantum defect curves are explained using the Fermi approximation. The permanent dipole moments of the Rydberg series reveal that they are determined by the sizes of the Rydberg orbitals, which are proportional to n{sup 2}. Interesting mirror relationships of the dipole moments are observed between l-mixed Rydberg series, with the rule Δl = ±1, except for s–d mixing, which is also accompanied by n-mixing. The members of the l-mixed Rydberg series have dipole moments with opposite directions. The first derivatives of the dipole moment curves, which show the charge-transfer component, clearly show not only mirror relationships in terms of direction but also oscillations. The transition dipole moment matrix elements of the Rydberg series are determined by the small-r region, with two consequences. One is that the transition dipole moment matrix elements show n{sup −3/2} dependence. The other is that the magnitudes of the transition dipole moment matrix elements decrease rapidly as l increases.

  1. Multiphoton Microwave Ionization of Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Gurian, Joshua Houston

    This thesis describes a series of multiphoton microwave experiments on Rydberg atoms when the microwave frequency is much greater than the classical Kepler frequency of the excited atoms. A new kHz pulse repetition frequency dye laser system was constructed for Rydberg lithium excitation with a linewidth as narrow as 3 GHz. This new laser system is used for first experiments of multiphoton microwave ionization of Rydberg lithium approaching the photoionization limit using 17 and 36 GHz microwave pulses. A multi-channel quantum defect model is presented that well describes the experimental results, indicating that these results are due to the coherent coupling of many atomic levels both above and below the classical ionization limit. Finally, preliminary results of measuring the final-state distributions of high lying Rydberg states after 17 GHz microwave pulses are presented.

  2. Efficient Multiparticle Entanglement via Asymmetric Rydberg Blockade

    SciTech Connect

    Saffman, M.; Moelmer, K.

    2009-06-19

    We present an efficient method for producing N particle entangled states using Rydberg blockade interactions. Optical excitation of Rydberg states that interact weakly, yet have a strong coupling to a second control state is used to achieve state dependent qubit rotations in small ensembles. On the basis of quantitative calculations, we predict that an entangled quantum superposition state of eight atoms can be produced with a fidelity of 84% in cold Rb atoms.

  3. Rydberg states of chloroform studied by VUV photoabsorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Singh, Param Jeet; Shastri, Aparna; D'Souza, R.; Jagatap, B. N.

    2013-11-01

    The VUV photoabsorption spectra of CHCl3 and CDCl3 in the energy region 6.2-11.8 eV (50,000-95,000 cm-1) have been investigated using synchrotron radiation from the Indus-1 source. Rydberg series converging to the first four ionization limits at 11.48, 11.91, 12.01 and 12.85 eV corresponding to excitation from the 1a2, 4a1, 4e, 3e, orbitals of CHCl3 respectively are identified and analyzed. Quantum defect values are observed to be consistent with excitation from the chlorine lone pair orbitals. Vibrational progressions observed in the region of 72,500-76,500 cm-1 have been reassigned to ν3 and combination modes of ν3+ν6 belonging to the 1a2→4p transition in contrast to earlier studies where they were assigned to a ν3 progression superimposed on the 3e→4p Rydberg transition. The assignments are further confirmed based on isotopic substitution studies on CDCl3 whose VUV photoabsorption spectrum is reported here for the first time. The frequencies of the ν3 and ν6 modes in the 4p Rydberg state of CHCl3 (CDCl3) are proposed to be ~454 (409) cm-1 and~130 (129) cm-1 respectively based on the vibronic analysis. DFT calculations of neutral and ionic ground state vibrational frequencies support the vibronic analysis. Experimental spectrum is found to be in good agreement with that predicted by TDDFT calculations. This work presents a consolidated analysis of the VUV photoabsorption spectrum of chloroform.

  4. Quantum-classical lifetimes of Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Junginger, Andrej; Main, Jörg; Wunner, Günter

    2013-04-01

    A remarkable property of Rydberg atoms is the possibility of creating molecules formed by one highly excited atom and another atom in the ground state. The first realization of such a Rydberg molecule has opened an active field of physical investigations, and showed that its basic properties can be described within a simple model regarding the ground state atom as a small perturber that is bound by a low-energy scattering process with the Rydberg electron (Greene et al 2000 Phys. Rev. Lett. 85 2458). Besides the good agreement between theory and the experiment concerning the vibrational states of the molecule, the experimental observations yield the astonishing feature that the lifetime of the molecule is clearly reduced as compared to the bare Rydberg atom (Butscher et al 2011 J. Phys. B: At. Mol. Opt. Phys. 44 184004). With focus on this yet unexplained observation, we investigate in this paper the vibrational ground state of the molecule in a quantum-classical framework. We show that the Rydberg wavefunction is continuously detuned by the presence of the moving ground state atom and that the timescale on which the detuning significantly exceeds the natural linewidth is in good agreement with the observed reduced lifetimes of the Rydberg molecule.

  5. Solvent interaction with the (2p3s) Rydberg state of hexamethylenetetramine: Energetics and relaxation dynamics

    NASA Astrophysics Data System (ADS)

    Shang, Q. Y.; Dion, C.; Bernstein, E. R.

    1994-07-01

    The (1+1) mass resolved excitation spectra are reported for the (2p3s)←(2p)2 Rydberg transition of the tricyclic, high symmetry molecule hexamethylenetetramine [HMT (C6H12N4)] and its van der Waals clusters. The solvent molecules employed include both nonpolar (Ar, CH4) and polar (NH3, CH3OCH3) species. HMT and its clusters are generated and cooled in a supersonic expansion. The observed electronic transition is assigned as T2←A1 within the Td print group. A transition blue shift of 52 cm-1 for each Ar atom and 65 cm-1 for each methane molecule in the HMT van der Waals cluster is characterized. These shifts are caused by an excited state repulsive interaction between the excited Rydberg electron and the closed shell solvent which reduces the attractive dispersion interaction between the HMT and nonpolar solvent species in the van der Waals cluster. A transition red shift of more than 600 cm-1 for NH3 and CH3OCH3 solvent/HMT clusters is observed; this large increase in interaction energy for the excited Rydberg state of HMT with respect to the ground state of HMT is associated with the delocalization of the excited electron into available (virtual) Rydberg orbitals of the solvent molecules. The interaction is characterized as an electron transfer interaction. These results and assignments are consistent with previously reported ones for DABCO/solvent clusters. Relaxation dynamics of excited HMT and its clusters are investigated via a pump/probe (ionization) technique. Relaxation of the clusters is dominated by an intersystem crossing mechanism resulting in an excited state singlet lifetime of ˜5 ns compared to a bare molecule HMT excited state lifetime of ˜1.0 μs. A triplet state of HMT lies 255 cm-1 below the first excited singlet Rydberg state as determined by two-color threshold ionization studies.

  6. Quadratic-in-spin effects in the orbital dynamics and gravitational-wave energy flux of compact binaries at the 3PN order

    NASA Astrophysics Data System (ADS)

    Bohé, Alejandro; Faye, Guillaume; Marsat, Sylvain; Porter, Edward K.

    2015-10-01

    We investigate the dynamics of spinning binaries of compact objects at the next-to-leading order in the quadratic-in-spin effects, which corresponds to the third post-Newtonian order (3PN). Using a Dixon-type multipolar formalism for spinning point particles endowed with spin-induced quadrupoles and computing iteratively in harmonic coordinates the relevant pieces of the PN metric within the near zone, we derive the post-Newtonian equations of motion as well as the equations of spin precession. We find full equivalence with available results. We then focus on the far-zone field produced by those systems and obtain the previously unknown 3PN spin contributions to the gravitational-wave energy flux by means of the multipolar post-Minkowskian wave generation formalism. Our results are presented in the center-of-mass frame for generic orbits, before being further specialized to the case of spin-aligned, circular orbits. Based on the energy balance equation, we derive the orbital phase of the binary at the order 3PN including all conservative spin effects and briefly discuss the relevance of the new terms.

  7. Laser cooling, trapping, and Rydberg spectroscopy of neutral holmium atoms

    NASA Astrophysics Data System (ADS)

    Hostetter, James Allen

    This thesis focuses on progress towards using ensembles of neutral holmium for use in quantum computing operations. We are particularly interested in using a switchable interaction between neutral atoms, the Rydberg blockade, to implement a universal set of quantum gates in a collective encoding scheme that presents many benefits over quantum computing schemes which rely on physically distinct qubits. We show that holmium is uniquely suited for operations in a collective encoding basis because it has 128 ground hyperfine states, the largest number of any stable, neutral atom. Holmium is a rare earth atom that is very poorly described for our purposes as it has never been cooled and trapped, its spectrum is largely unknown, and it presents several unique experimental challenges related to its complicated atomic structure and short wavelength transitions. We demonstrate important progress towards overcoming these challenges. We produce the first laser cooling and trapping of holmium into a MOT. Because we use a broad cooling transition, our cooling technique does not require the use of a Zeeman slower. Using MOT depletion spectroscopy, we provide precise measurements of holmium's Rydberg states and its ionization potential. Our work continues towards cooling holmium into a dipole trap by calculating holmium's AC polarizability and demonstrating the results of early attempts at an optical dipole trap. We provide details of future upgrades to the experimental apparatus and discuss interesting potential for using holmium in quantum computing using single atoms in a magnetically trapped lattice. This thesis shows several promising indicators for continued work in this field.

  8. Trapping Rydberg Atoms in an Optical Lattice

    NASA Astrophysics Data System (ADS)

    Anderson, Sarah E.

    2012-06-01

    Optical lattice traps for Rydberg atoms are of interest in advanced science and in practical applications. After a brief discussion of these areas of interest, I will review some basics of optical Rydberg-atom trapping. The trapping potential experienced by a Rydberg atom in an optical lattice is given by the spatial average of the free-electron ponderomotive energy weighted by the Rydberg electron's probability distribution. I will then present experimental results on the trapping of ^85Rb Rydberg atoms in a one-dimensional ponderomotive optical lattice (wavelength 1064 nm). The principal methods employed to study the lattice performance are microwave spectroscopy, which is used to measure the lattice's trapping efficiency, and photo-ionization, which is used to measure the dwell time of the atoms in the lattice. I have achieved a 90% trapping efficiency for ^85Rb 50S atoms by inverting the lattice immediately after laser excitation of ground-state atoms into Rydberg states. I have characterized the dwell time of the atoms in the lattice using photo-ionization of 50D5/2 atoms. In continued work, I have explored the dependence of the Rydberg-atom trapping potential on the angular portion of the atomic wavefunction. Distinct angular states exhibit different trapping behavior in the optical lattice, depending on how their wavefunctions are oriented relative to the lattice planes. Specifically, I have measured the lattice potential depth of sublevels of ^85Rb nD atoms (50<=n<=65) in a one-dimensional optical lattice with a transverse DC electric field. The trapping behavior varies substantially for the various angular sublevels, in agreement with theory. The talk will conclude with an outlook into planned experiments.

  9. Thermal Casimir-Polder shifts in Rydberg atoms near metallic surfaces

    SciTech Connect

    Crosse, J. A.; Clements, Kate; Buhmann, Stefan Y.; Scheel, Stefan; Ellingsen, Simen A.

    2010-07-15

    The Casimir-Polder (CP) potential and transition rates of a Rydberg atom above a plane metal surface at finite temperature are discussed. As an example, the CP potential and transition rates of a rubidium atom above a copper surface at 300 K are computed. Close to the surface we show that the quadrupole correction to the force is significant and increases with increasing principal quantum number n. For both the CP potential and decay rates one finds that the dominant contribution comes from the longest wavelength transition and the potential is independent of temperature. We provide explicit scaling laws for potential and decay rates as functions of atom-surface distance and principal quantum number of the initial Rydberg state.

  10. Spectrum of plasma containing Ne- and Na-like ions: consistent account for Rydberg and autoionizing Rydberg series in balance equations

    NASA Astrophysics Data System (ADS)

    Ivanov, L. N.; Ivanova, E. P.; Knight, L. V.; Molchanov, A. G.

    1996-06-01

    This is a theoretical study of argon plasma under conditions, where Ne- and Na-like ionization stages are dominant. Balance equations are generalized to treat 37 3l states of Ne-like ion and 37 adjacent series of Rydberg states of Na-like ion simultaneously. This allows us to include in the kinetics a diffusion-like motion of the state of the system "Ne-like ion plus one electron" through the multitude of excited levels spread over an energy region of 50 eV. The populations Ni - i (i = (1, ..., 37)) of the Ne-like ion states are introduced explicitly; those of adjacent 37 Rydberg series are accounted for through continuous functions Ni(ɛ). These functions describe the population distribution within each Rydberg series dependent on the Rydberg electron enegy ɛ. The elementary processes of the collisionalradiative model connecting all Ne- and Na-like states, as well as processes of redistribution of populations inside each Rydberg series, are accounted for. The rate coefficients for all processes within the Ne-like residue have been calculated previously, using a detailed many-body relativistic theory. The dielectric capture cross sections and autoionization probabilities are presented as analytical continuation of the collisional excitation cross sections. The excited-excited states transitions are included. The rest of the processes are treated in a simple semiclassical approximation. The Lotz formula is generalized by unambiguous analytical continuation to cover the case of bound-bound transitions between Rydberg states of Na-like ions. The radiation reabsorption in a long plasma cylinder is included through Biberman-Holstein coefficients for all transitions. The inclusion of Na-like states, accounting for diffusion-like processes, increases the population inversion for the "lasing candidates" by at least a factor of two for a wide range of plasma conditions. This is important for the ionization equilibrium too. Besides, the functions Ni(ɛ) bear diagnostic

  11. Fractional quantum Hall states of Rydberg polaritons

    NASA Astrophysics Data System (ADS)

    Maghrebi, Mohammad F.; Yao, Norman Y.; Hafezi, Mohammad; Pohl, Thomas; Firstenberg, Ofer; Gorshkov, Alexey V.

    2015-03-01

    We propose a scheme for realizing fractional quantum Hall states of light. In our scheme, photons of two polarizations are coupled to different atomic Rydberg states to form two flavors of Rydberg polaritons that behave as an effective spin. An array of optical cavity modes overlapping with the atomic cloud enables the realization of an effective spin-1 /2 lattice. We show that the dipolar interaction between such polaritons, inherited from the Rydberg states, can be exploited to create a flat, topological band for a single spin-flip excitation. At half filling, this gives rise to a photonic (or polaritonic) fractional Chern insulator—a lattice-based, fractional quantum Hall state of light.

  12. Ionization of Rydberg atoms colliding with a metal surface

    SciTech Connect

    Sjakste, J.; Borisov, A. G.; Gauyacq, J. P.

    2006-04-15

    We report on a theoretical study of the ionization process of Xe* Rydberg atoms colliding with a metal surface, in the presence of an external electric field. The evolution of the Xe* outer electron is studied by a wave packet propagation approach, allowing to include all dynamical aspects of the collision, in particular nonadiabatic inter-Rydberg transitions. We investigate how the different Xe* Stark states formed in the external field couple together and ionize on the surface and how the different polarizations of the electronic cloud in the Xe* states are reflected in their ionization properties. We show that the presence of the external electric field can significantly perturb the dynamics of the ionization process. Our results account for recent results from Dunning et al. [Nucl. Inst. Meth. B 203, 69 (2003)]. In particular, it is explained how the external electric field present in the experimental procedure of Dunning et al. leads to the apparent absence of a polarization effect in the ionization process.

  13. Measuring Microwaves via Absorption and Dispersion in Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Stack, Daniel; Kunz, Paul; Meyer, David; Solmeyer, Neal

    2016-05-01

    Weak microwave frequency electromagnetic fields can be difficult to detect and fully characterize with traditional methods. However it is possible to transduce the measurement of these fields from the microwave domain to the optical domain via resonant transitions between Rydberg levels in atomic vapors using electromagnetically-induced transparency and the Autler-Townes effect. This technique allows for sensitive measurements of the microwave field amplitude, polarization, and spatial waveform (via the position of the probe and coupling laser beams) as compared to measurements performed with dipole antennas. We are able to obtain these quantities by monitoring the properties of a probe laser beam as it passes through a rubidium vapor cell. Previous experiments using Rydberg spectroscopy have typically relied on measuring the absorption of the probe laser as it passed through the atomic system. We report on progress to use the polarization rotation of the probe as it passes through the atoms in a static magnetic field, which corresponds to the real part of the susceptibility of the atomic medium, for measuring the characteristics of a microwave frequency signal. This effect is known as Nonlinear Magneto Optical Rotation (NMOR) and has been used for sensitive magnetometry.

  14. \\cal{PT} -symmetry in Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Ziauddin; Chuang, You-Lin; Lee, Ray-Kuang

    2016-07-01

    We propose a scheme to realize parity-time ( {PT} )-symmetry in an ensemble of strongly interacting Rydberg atoms, which act as superatoms due to the dipole blockade mechanism. We show that Rydberg-dressed 87Rb atoms in a four-level inverted Y-type configuration is highly efficient to generate the refractive index for a probe field, with a symmetric (antisymmetric) profile spatially in the corresponding real (imaginary) part. Comparing with earlier investigations, the present scheme provides a versatile platform to control the system from {PT} -symmetry to non-PT -symmetry via different external parameters, i.e., coupling field detuning, probe field intensity and control field intensity.

  15. Optical Mixing of Rydberg Angular Momenta

    SciTech Connect

    Corless, J.D.; Stroud, C.R., Jr.

    1997-07-01

    When optical frequency fields are used to couple a ground state to a Rydberg state, the resonant dipole coupling is to a low angular momentum state. Higher angular momentum states are typically thought not to play a role in the excitation. The extremely large dipole matrix elements coupling Rydberg states of the same n but differing l , however, allow optical fields of modest strengths to produce Rabi frequencies larger than optical frequencies. We demonstrate that these optical fields can therefore readily excite the higher angular momentum states, and we examine the consequences of this coupling. {copyright} {ital 1997} {ital The American Physical Society}

  16. Phase Modulation in Rydberg Dressed Multi-Wave Mixing processes.

    PubMed

    Zhang, Zhaoyang; Zheng, Huaibin; Yao, Xin; Tian, Yaling; Che, Junling; Wang, Xiuxiu; Zhu, Dayu; Zhang, Yanpeng; Xiao, Min

    2015-01-01

    We study the enhancement and suppression of different multi-waving mixing (MWM) processes in a Rydberg-EIT rubidium vapor system both theoretically and experimentally. The nonlinear dispersion property of hot rubidium atoms is modulated by the Rydberg-Rydberg interaction, which can result in a nonlinear phase shift of the relative phase between dark and bright states. Such Rydberg-induced nonlinear phase shift can be quantitatively estimated by the lineshape asymmetry in the enhancedand suppressed MWM processes, which can also demonstrate the cooperative atom-light interaction caused by Rydberg blockaded regime. Current study on phase shift is applicable to phase-sensitive detection and the study of strong Rydberg-Rydberg interaction. PMID:26053438

  17. Phase Modulation in Rydberg Dressed Multi-Wave Mixing processes

    PubMed Central

    Zhang, Zhaoyang; Zheng, Huaibin; Yao, Xin; Tian, Yaling; Che, Junling; Wang, Xiuxiu; Zhu, Dayu; Zhang, Yanpeng; Xiao, Min

    2015-01-01

    We study the enhancement and suppression of different multi-waving mixing (MWM) processes in a Rydberg-EIT rubidium vapor system both theoretically and experimentally. The nonlinear dispersion property of hot rubidium atoms is modulated by the Rydberg-Rydberg interaction, which can result in a nonlinear phase shift of the relative phase between dark and bright states. Such Rydberg-induced nonlinear phase shift can be quantitatively estimated by the lineshape asymmetry in the enhancedand suppressed MWM processes, which can also demonstrate the cooperative atom-light interaction caused by Rydberg blockaded regime. Current study on phase shift is applicable to phase-sensitive detection and the study of strong Rydberg-Rydberg interaction. PMID:26053438

  18. Three pro-nuclei (3PN) incidence factors and clinical outcomes: a retrospective study from the fresh embryo transfer of in vitro fertilization with donor sperm (IVF-D)

    PubMed Central

    Li, Mingzhao; Zhao, Wanqiu; Xue, Xia; Zhang, Silin; Shi, Wenhao; Shi, Juanzi

    2015-01-01

    Objectives: The aim of this study was to explore the main factors of 3PN incidence and determine whether the presence of 3PN could lead to a worse pregnancy outcome. Methods: This study included 508 IVF-D (in vitro fertilization with donor sperm) cycles from January 2013 to September 2014. The patients were divided into three groups as follows: group 1 included patients with no 3PN zygotes, group 2 included patients with 1%-25% 3PN zygotes and group 3 included patients with > 25% 3PN zygotes. Results: We observed that more retrieved oocytes and higher HCG day peak E2 value could result in 3PN incidence more easily. When the 3PN zygotes rate was > 25%, the percentages of normal fertilization (68.4% and 66.3% and 46.4%, P < 0.001), day 3 grade I+II embryos (41.2% and 38.6% and 25.8%, P < 0.001), day 3 grade I+II+III embryos (68.7% and 65.2% and 61.4%, P = 0.032) and implantation rates (52.1% and 50.8% and 45.4%, P = 0.026) were significantly lower than that in the other two groups respectively. The pregnancy rate was lower in 3PN > 25% group than that in the other two groups but there was no significant difference (65.2% and 66.7% and 55.6%, P = 0.266). The cleavage (98.3% and 97.2% and 98.2%, P = 0.063) and early abortion (7.1% and 8.0% and 8.6%, P = 0.930) rate were identical among three groups. Conclusions: More retrieved oocytes and higher HCG day peak E2 value could result in 3PN incidence more easily. Interestingly, normal fertilization rate, day-3 grade I+II embryos rate, day-3 grade I+II+III embryos rate and implantation rate were significantly lower in IVF-D cycles with a 3PN incidence of > 25%. The number of day-3 grade I+II embryos might be a key factor for pregnancy in IVF-D cycles with a 3PN incidence of > 25%. PMID:26550358

  19. Heavy-Rydberg ion-pair formation in collisions of Rydberg atoms with attaching targets

    NASA Astrophysics Data System (ADS)

    Wang, Changhao; Kelley, Michael; Dunning, F. Barry

    2012-06-01

    Collisions between K(np) Rydberg atoms and electron attaching targets can lead to the creation of heavy-Rydberg ion-pair states comprising a weakly-bound positive-negative ion pair orbiting at large internuclear separations. The lifetimes of such states and their correlation with binding energy and the channels available for decay, which can be controlled by varying n, the Rydberg atom velocity, and the target species, are being investigated. The ion-pair states are produced in a small collision cell and allowed to exit to form a beam that passes between a pair of electrodes where their number and binding energy distribution is determined by electric field induced dissociation. Ion-pair production is analyzed with the aid of a Monte Carlo collision code that models both initial Rydberg electron capture and the subsequent evolution of the product ion pair. Research supported by the Robert A Welch Foundation.

  20. EDITORIAL: Special issue on Rydberg physics

    NASA Astrophysics Data System (ADS)

    Côté, Robin; Pattard, Thomas; Weidemüller, Matthias

    2005-01-01

    Atoms and molecules in highly excited electronic states ('Rydberg atoms') have been the object of broad scientific research for almost a century. Despite this long history, the field of research has never lost its buoyancy, and recent years in particular have seen a tremendous revival of interest in the physics of Rydberg atoms and molecules from many different perspectives. Rydberg systems touch a wide range of research areas including, among others, ultralong-range molecules, artificial ('designer') atoms, quantum chaos, quantum information, ultracold Rydberg gases and plasmas, and anti-hydrogen formation. Due to the many fields involved, the physical insight and technical know-how are scattered over different communities. The goal of this special issue is to provide an integral overview of the latest developments in this highly innovative research field and to make the physical knowledge available to a wide audience. Groups from various fields of atomic, molecular and optical physics as well as condensed matter and plasma physics have contributed to this issue, which therefore spans a wide range of areas connected through the common theme: 'Rydberg physics'. This name was given to a four-week International Workshop and Seminar which was held from 19 April to 14 May 2004 at the Max-Planck-Institut für Physik Komplexer Systeme in Dresden, Germany, and organized by the three of us. The workshop and seminar programme was a very successful mixture of topics bringing together colleagues working in different but related areas of research centred about the physics of highly excited Rydberg atoms and molecules. We would like to take this opportunity to express our gratitude to the organization team of the MPI-PKS Dresden, especially the Director, Jan-Michael Rost, and the Visitors' Programme coordinator, Mandy Lochar. The generous support of the Max Planck Society, which made this successful workshop and seminar possible, is also gratefully acknowledged. Inspired by the

  1. Resonant electric dipole-dipole interactions between cold Rydberg atoms in a magnetic field

    NASA Astrophysics Data System (ADS)

    Afrousheh, Kourosh; Bohlouli-Zanjani, Parisa; Carter, Jeffery; Mugford, Ashton; Martin, James D. D.

    2006-05-01

    Laser cooled Rb atoms were optically excited to 46d5/2 Rydberg states. A microwave pulse transferred a fraction of the atoms to the 47p3/2 Rydberg state. The resonant electric dipole-dipole interactions between atoms in these two states were probed using the linewidth of the two-photon microwave transitions 46d5/2 -- 47d5/2. The presence of a weak magnetic field (roughly 1 G) reduced the observed line broadening, indicating that the interaction is suppressed by the field. The field removes some of the energy degeneracies responsible foe the resonant interaction, and this is the basis for a quantitative model of the resulting suppression. A technique for the calibration of magnetic field strengths using the 34s1/2 -- 34p1/2 one-photon transition is also presented.

  2. Resonant electric dipole-dipole interactions between cold Rydberg atoms in a magnetic field

    NASA Astrophysics Data System (ADS)

    Afrousheh, K.; Bohlouli-Zanjani, P.; Carter, J. D.; Mugford, A.; Martin, J. D. D.

    2006-06-01

    Laser-cooled Rb85 atoms were optically excited to 46d5/2 Rydberg states. A microwave pulse transferred a fraction of the atoms to the 47p3/2 Rydberg state. The resonant electric dipole-dipole interactions between atoms in these two states were probed using the linewidth of the two-photon microwave transition 46d5/2-47d5/2 . The presence of a weak magnetic field ≈0.5G reduced the observed line broadening, indicating that the interaction is suppressed by the field. The field removes some of the energy degeneracies responsible for the resonant interaction, and this is the basis for a quantitative model of the resulting suppression. A technique for the calibration of magnetic field strengths using the 34s1/2-34p1/2 one-photon transition is also presented.

  3. Spin squeezing in a Rydberg lattice clock.

    PubMed

    Gil, L I R; Mukherjee, R; Bridge, E M; Jones, M P A; Pohl, T

    2014-03-14

    We theoretically demonstrate a viable approach to spin squeezing in optical lattice clocks via optical dressing of one clock state to a highly excited Rydberg state, generating switchable atomic interactions. For realistic experimental parameters, these interactions are shown to generate over 10 dB of squeezing in large ensembles within a few microseconds and without degrading the subsequent clock interrogation. PMID:24679291

  4. Rydberg Impurity Probes in Ultracold Gases

    NASA Astrophysics Data System (ADS)

    Mitchison, Mark; Johnson, Tomi; Plenio, Martin; Jaksch, Dieter

    2015-03-01

    Impurities immersed in ultracold gases can act as highly sensitive, tunable and potentially non-destructive probes of their environment. In this setting, we propose the use of an atomic impurity in a Rydberg state to measure density fluctuations via Ramsey interferometry. The rapid collisional dynamics of the light Rydberg electron interacting with the heavy gas particles, combined with the capability to quickly change the state of the impurity with optical pulses, make such a probe ideal for measuring local properties of ultracold gases. Our proposed device promises angle-resolved density measurements with sub-micron spatial resolution, and with no need to integrate over the line of sight. We outline how Rydberg impurity probes could be applied to study various interesting quantum states of current experimental relevance. We also discuss the possibility of using multiple Rydberg atoms to extract the spatial pair distribution function g (2) (r). Our work is placed in the context of other recently proposed impurity-based probes.

  5. Molecular ions, Rydberg spectroscopy and dynamics

    SciTech Connect

    Jungen, Ch.

    2015-01-22

    Ion spectroscopy, Rydberg spectroscopy and molecular dynamics are closely related subjects. Multichannel quantum defect theory is a theoretical approach which draws on this close relationship and thereby becomes a powerful tool for the study of systems consisting of a positively charged molecular ion core interacting with an electron which may be loosely bound or freely scattering.

  6. Vibrational modes in excited Rydberg states of acetone: A computational study

    NASA Astrophysics Data System (ADS)

    Shastri, Aparna; Singh, Param Jeet

    2016-04-01

    Computational studies of electronically excited states of the acetone molecule [(CH3)2CO] and its fully deuterated isotopologue [(CD3)2CO] are performed using the time dependent density functional (TDDFT) methodology. In addition to vertical excitation energies for singlet and triplet states, equilibrium geometries and vibrational frequencies of the n=3 Rydberg states (3s, 3p and 3d) are obtained. This is the first report of geometry optimization and frequency calculations for the 3px, 3pz, 3dyz, 3dxy, 3dxz, 3dx2-y2 and 3dz2 Rydberg states. Results of the geometry optimization indicate that the molecule retains approximate C2V geometry in most of these excited Rydberg states, with the most significant structural change seen in the CCO bond angle which is found to be reduced from the ground state value. Detailed comparison of the computationally predicted vibrational wavenumbers with experimental studies helps to confirm several of the earlier vibronic assignments while leading to revised/new assignments for some of the bands. The important role of hot bands in analysis of the room temperature photoabsorption spectra of acetone is corroborated by this study. While the vibrational frequencies in excited Rydberg states are overall found to be close to those of the ionic ground state, geometry optimization and vibrational frequency computation for each excited state proves to be very useful to arrive at a consistent set of vibronic assignments. Isotopic substitution helps in consolidating and confirming assignments. An offshoot of this study is the interpretation of the band at ~8.47 eV as the π-3s Rydberg transition converging to the second ionization potential.

  7. Observation of g/u-symmetry mixing in the high-n Rydberg states of HD

    SciTech Connect

    Sprecher, Daniel; Merkt, Frédéric

    2014-03-28

    The structure and dynamics of high-n Rydberg states belonging to series converging to the (v{sup +} = 0, N{sup +} = 0–2) levels of the X{sup +2}Σ{sub g}{sup +} electronic ground state of HD{sup +} were studied by high-resolution spectroscopy from the GK{sup 1}Σ{sub g}{sup +} (v= 1, N = 1) state under field-free conditions. Three effects of g/u-symmetry breaking were detected: (i) Single-photon transitions from the GK (v = 1, N = 1) state of gerade symmetry to the 30d2{sub 1} and 31g2{sub 2} Rydberg states of gerade symmetry were observed after careful compensation of the stray electric fields. (ii) The singlet 61p1{sub 2} Rydberg state of ungerade symmetry was found to autoionize to the N{sup +} = 0, ℓ = 2 ionization continuum of gerade symmetry with a lifetime of 77(10) ns. (iii) Shifts of up to 20 MHz induced by g/u-symmetry mixing were measured for members of the np1{sub 1} Rydberg series which lie close to nd2{sub 1} Rydberg states. These observations were analyzed in the framework of multichannel quantum-defect theory. From the observed level shifts, the off-diagonal eigenquantum-defect element μ{sub pd} of singlet-π symmetry was determined to be 0.0023(3) and the corresponding autoionization dynamics could be characterized. The ionization energy of the GK (v = 1, N = 1) state of HD was determined to be 12 710.544 23(10) cm{sup −1}.

  8. Dissociative ionization of sodium molecules via repulsive Rydberg states

    NASA Astrophysics Data System (ADS)

    Chen, Hong

    In this thesis, an investigation of two color resonance multiphoton ionization (REMPI) and fragmentation processes in Na2 has been performed in combination with Linear Time-of-Flight Mass Spectrometry technique. The ionization and dissociative ionizations channels in the energy range up to 2500cm -1 above the dissociative ionization threshold into Na(3s)+Na ++e have been studied. After a mild supersonic expansion from the beam source, neutral sodium dimers in the ground state have been produced. Two tunable, pulsed lasers excite Na2 molecules via the intermediate A1S+u state to a single ro-vibrational level of the second intermediate 21pig state. Following absorption of a third photon, the total energy is above the dissociation limit into Na(3s) + Na+ + e. Typically, a small portion of atomic ions is produced under our experimental conditions. By varying the total available energy below and through the doubly excited states correlating with the Na(3p)+Na(4s) atom pair, there is no evidence that the doubly excited states positioned in the ionic continuum get involved. By calculation of the expected transition probabilities for all possible channels which can decay directly and indirectly into atomic ions, I find that direct dissociative ionization via 12S+u is impossible. The transition probabilities for dissociative ionization via the repulsive Rydberg states with principal quantum numbers n from 5˜12 converging toward the 12S+u state are three to four orders of magnitude larger than those for direct ionization into the continuum of the X2S+g ground state. These repulsive Rydberg states are much more likely to play a role in the photo-ionization through the intermediate 21Pg state. A semi-classical model which was originally developed for negative ion dissociative attachment (O'MAL'67) describes how dissociative ionization occurs along the repulsive Rydberg states. Its prediction concerning the ratio of atomic to molecular ion production as a function of initial

  9. Cavity polaritons with Rydberg blockade and long-range interactions

    NASA Astrophysics Data System (ADS)

    Litinskaya, Marina; Tignone, Edoardo; Pupillo, Guido

    2016-08-01

    We study interactions between polaritons, arising when photons strongly couple to collective excitations in an array of two-level atoms trapped in an optical lattice inside a cavity. We consider two types of interactions between atoms: dipolar forces and atomic saturability, which range from hard-core repulsion to Rydberg blockade. We show that, in spite of the underlying repulsion in the subsystem of atomic excitations, saturability induces a broadband bunching of photons for two-polariton scattering states. We interpret this bunching as a result of interference, and trace it back to the mismatch of the quantization volumes for atomic excitations and photons. We also examine bound bipolaritonic states: these include states created by dipolar forces, as well as a gap bipolariton, which forms solely due to saturability effects in the atomic transition. Both types of bound states exhibit strong bunching in the photonic component. We discuss the dependence of bunching on experimentally relevant parameters.

  10. Millimeter-wave rubidium Rydberg van der Waals spectroscopy

    SciTech Connect

    Han Jianing; Gallagher, T. F.

    2009-05-15

    We have observed the diatomic nsns{yields}ns(n+1)s{yields}(n+1)s(n+1)s microwave transitions of pairs of cold Rb Rydberg atoms for 36

  11. Laser resonance photoionization spectroscopy of Rydberg levels in Fr

    SciTech Connect

    Andreev, S.V.; Letokhov, V.S.; Mishin, V.I.

    1987-09-21

    We investigated for the first time the high-lying Rydberg levels in the rare radioactive element francium (Fr). The investigations were conducted by the highly sensitive laser resonance atomic photoionization technique with Fr atoms produced at a rate of about 10/sup 3/ atoms/s in a hot cavity. We measured the wave numbers of the 7p/sup 2/P/sub 3/2/..-->..nd/sup 2/D (n = 22--33) and 7p/sup 2/P/sub 3/2/..-->..ns/sup 2/S (n = 23, 25--27,29--31) transitions and found the binding energy of the 7p/sup 2/P/sub 3/2/ state to be T = -18 924.8(3) cm/sup -1/, which made it possible to establish accurately the ionization potential of Fr.

  12. Intrication de deux atomes en utilisant le blocage de Rydberg

    NASA Astrophysics Data System (ADS)

    Gaëtan, A.

    2010-12-01

    Considérons un système quantique constitué de deux sous-systèmes : on dit qu'il est dans un état intriqué s'il existe des corrélations quantiques entre les états de ces derniers. La compréhension et la mise en œuvre d'états intriqués ont de nombreuses applications (métrologie quantique, étude des systèmes fortement corrélés, traitement quantique de l'information, etc.) et constituent le contexte général de ce travail de thèse. Plus en détail, nous démontrons la réalisation d'un état intriqué de deux atomes neutres piégés indépendamment. Pour cela, nous exploitons le phénomène de blocage de Rydberg : lorsqu'on essaie d'exciter simultanément deux atomes séparés de quelques micromètres vers un état de Rydberg donné, la forte interaction entre atomes de Rydberg peut empêcher cette excitation simultanée. Dans ce cas, seul un des deux atomes est excité et l'on génère ainsi des corrélations quantiques entre les états des deux atomes, c'est-à-dire de l'intrication. Dans notre expérience, deux atomes de 87Rb dans l'état fondamental 5S1/2 sont piégés chacun dans une pince optique microscopique, à une distance relative de 4 micromètres. En réalisant des transitions entre l'état 5S1/2 et l'état de Rydberg 58D3/2 par des transitions à deux photons, nous obtenons un état intriqué des deux atomes dans les sous-niveaux |5S1/2, f = 1, mf = 1> et |5S1/2, f = 2, mf = 2>. Afin de quantifier l'intrication, nous mesurons la fidélité par rapport à l'état-cible en réalisant des transitions Raman entre ces deux sous-niveaux. La fidélité des paires d'atomes présentes à la fin de l'expérience est supérieure à la valeur seuil de 0,5, ce qui prouve la création d'un état intriqué.

  13. Two Dimensional Non-commutative Space and Rydberg Atom Model

    NASA Astrophysics Data System (ADS)

    Chung, Won Sang

    2015-06-01

    In this paper we consider the case of only space-space non-commutativity in two dimension. We also discuss the Rydberg atom model in this space and use the linear realization of the coordinate and momentum operators to solve the Schrödinger equation for the Rydberg atom through the standard perturbation method. Finally, the thermodynamics for the Rydberg atom model is discussed.

  14. Vibronic and Rydberg series assignments in the vacuum ultraviolet absorption spectrum of nitrous oxide

    NASA Astrophysics Data System (ADS)

    Shastri, Aparna; Singh, Param Jeet; Krishnakumar, Sunanda; Mandal, Anuvab; Raja Sekhar, B. N.; D'Souza, R.; Jagatap, B. N.

    2014-11-01

    We report a comprehensive photoabsorption study of nitrous oxide (N2O) in the vacuum ultraviolet (45,000-95,000 cm-1) region using synchrotron radiation. The observed spectrum comprises of a few valence transitions and low lying Rydberg series converging to the two spin-orbit components (2П1/2,3/2) of the ground state of N2O+. Spectral analysis is aided by extensive quantum chemical calculations of vertical excited states, oscillator strengths and potential energy curves using the time dependent density functional theory. Vibronic bands observed in the first absorption system (45,000-60,000 cm-1) are assigned to hot band progressions in υ2‧ originating from v″=1 or 2. New insights into the assignment of the well-formed progression of bands in the X1Σ+→C1П system (60,000-72,000 cm-1) are afforded by consideration of the Renner-Teller interaction. A set of molecular vibrational parameters (ω2=467 cm-1, x22=-2.9, ε=-0.24) for the C1П state are derived from a fitting of the experimental data. The 3pπ1Σ+ state at ~77,600 cm-1 shows a large quantum defect (0.96) which is explained as arising due to mixed valence-Rydberg character. In the 85,000-95,000 cm-1 region, a number of absorption features are observed with greater clarity than in earlier photoabsorption studies and assigned to Rydberg series of type nlλ (n=3,4; l=s,p,d; λ=σ,π,δ) and accompanying vibronic bands. This work has resulted in clarification of several discrepancies in earlier Rydberg series assignments. Additionally, the 3pπ 3Σ- Rydberg state at 85,788 cm-1, the valence transition 7σ→3π (1П) at 87,433 cm-1 and the 3dλ Rydberg series in the 91,700-92,600 cm-1 region are assigned for the first time.

  15. Ultracold Long-Range Rydberg Molecules with Complex Multichannel Spectra

    NASA Astrophysics Data System (ADS)

    Eiles, Matthew; Greene, Chris

    2016-05-01

    A generalized class of exotic long-range Rydberg molecules consisting of a multichannel Rydberg atom bound to a distant ground state atom by the Rydberg electron is predicted. These molecules are characterized by the rich physics provided by the strongly perturbed multichannel Rydberg spectra of divalent atoms, in contrast to the regular Rydberg series of the alkali atoms used to form Rydberg molecules to date. These multichannel Rydberg molecules exhibit favorable properties for laser excitation, because states exist where the quantum defect varies strongly with the principal quantum number n. In particular, the nd Rydberg state of calcium becomes nearly degenerate with states of high orbital angular momentum over the range 17 < n < 22 , promoting its admixture into the high l deeply bound ``trilobite'' molecule states and thereby circumventing the usual difficulty posed by electric dipole selection rules. Further novel molecular states are predicted to occur in the low- J states of silicon, which are strongly perturbed due to channel interactions between Rydberg series leading to the spin-orbit split ionization thresholds. These interactions manifest themselves in potential curves exhibiting two distinct length scales, providing novel opportunities for quantum manipulation. Supported in part by the National Science Foundation under Grant No. PHY-1306905.

  16. Ultralong-range triatomic Rydberg molecules in an electric field

    NASA Astrophysics Data System (ADS)

    Aguilera Fernández, Javier; Schmelcher, Peter; González-Férez, Rosario

    2016-06-01

    We investigate the electronic structure of a triatomic Rydberg molecule formed by a Rydberg atom and two neutral ground-state atoms. Taking into account the s-wave and p-wave interactions, we perform electronic structure calculations and analyze the adiabatic electronic potentials evolving from the Rb (n=35,l≥slant 3) Rydberg degenerate manifold. We hereby focus on three different classes of geometries of the Rydberg molecules, including symmetric, asymmetric and planar configurations. The metamorphosis of these potential energy surfaces in the presence of an external electric field is explored.

  17. The rise of Rydberg physics

    NASA Astrophysics Data System (ADS)

    Cooper, Keith

    2016-04-01

    Quantum computers of the future could operate via the energy transitions of excited atoms, or even from pure light, if a rapidly growing area of atomic physics continues to meet with success, writes Keith Cooper.

  18. Tests of Theory in Rydberg States of One-Electron Ions

    NASA Astrophysics Data System (ADS)

    Tan, Joseph N.; Mohr, Peter J.

    Comparison of optical frequency measurements to predictions of quantum electrodynamics (QED) for Rydberg states of one-electron ions can test theory and allow new determinations of constants of nature to be made. Simplifications in the QED theory of high-angular-momentum states reduces the uncertainty in the prediction of transition frequencies to a level where a new value of the Rydberg constant which is independent of the proton radius can be determined. Since the energy-level spacing between neighbouring Rydberg states grows as the square of the nuclear charge number, it is possible to study transitions with optical frequencies that are accessible to femtosecond laser frequency combs. Recently at the US National Institute of Standards and Technology (NIST), highly charged ions (including bare nuclei) created in an Electron Beam Ion Trap (EBIT) were extracted and captured in a novel compact Penning trap. An ongoing experiment aims to produce one-electron ions isolated in an ion trap designed for laser spectroscopy. Tests of theory in a regime free of nuclear effects would be valuable in shedding light on the puzzle surrounding the large discrepancy in the value of the proton radius inferred from the observed Lamb shift in muonic hydrogen as compared to the value deduced from hydrogen and deuterium spectroscopy and electron scattering measurements.

  19. Collisional destruction of circular Rydberg states by atoms with small electron affinities

    NASA Astrophysics Data System (ADS)

    Mironchuk, Elena S.; Narits, Alexander A.; Lebedev, Vladimir S.

    2014-12-01

    The results of theoretical studies of interaction between neutral targets with small electron affinities and Rydberg atoms in circular states are reported. The cross sections of collisional destruction of such states due to the resonant quenching mechanism are calculated on the basis of the semiclassical theory of nonadiabatic transitions between the ionic and Rydberg covalent terms of a quasimolecule combined with recently developed technique for exact evaluation of matrix elements. We obtain the basic formula for the square of the coupling parameter involving Rydberg nlm-state with the given values of the principal, orbital, and magnetic quantum numbers. It is employed for the derivation of explicit expressions for transitions from circular states applicable in cases of s- and p-states of negative ion temporarily formed during a collision of atoms. Numerical calculations are carried out for thermal collisions of Li∗ and Na∗ atoms with Ca(4s2) and Sr(5s2). We explore n-, l-, m-, and velocity-dependences of the cross sections and analyze orientation effects in such collisions. Cross sections of resonant quenching for circular states (l = | m | = n - 1) are shown to be much smaller than those for states with small l values and typically two times lower than for nearly-circular states (l = n - 1) averaged over m.

  20. Experimental efforts at NIST towards one-electron ions in circular Rydberg states

    NASA Astrophysics Data System (ADS)

    Tan, Joseph N.; Brewer, Samuel M.; Guise, Nicholas D.

    2011-06-01

    Experimental effort is underway at NIST to enable tests of theory with one-electron ions synthesized in circular Rydberg states from captured bare nuclei. Problematic effects that limit the accuracy of predicted energy levels for low-lying states are vanishingly small for high-angular-momentum (high-L) states; in particular, the nuclear size correction for high-L states is completely negligible for any foreseeable improvement of measurement precision. As an initial step towards realizing such states, highly charged ions are extracted from the NIST electron beam ion trap (EBIT) and steered through the electrodes of a Penning trap. The goal is to capture bare nuclei in the Penning trap for experiments to make one-electron atoms in circular Rydberg states with dipole (E1) transitions in the optical domain accessible to a frequency comb.

  1. Spin Transport in Ultracold Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Hollingsworth, Jacob; Mukherjee, Rick; Killian, Thomas; Hazzard, Kaden

    2016-05-01

    We devise a scheme to use ultracold Rydberg atoms to study models of transport where Rydberg excitations play the role of tunneling particles. In contrast to previous schemes, where ``tunnelings'' between atoms separated by a distance r often scale as 1 /r3 , ours scale as 1 /r6 , for which the physics is more similar to short-ranged hopping models. We theoretically demonstrate that current experiments exist in a regime that allows significant transport well within the experimental lifetime - several microns in a microsecond, and derive the experimental parameters for strontium atoms that are necessary to access this regime. We also show how disorder may be introduced and controlled precisely via the depth of an applied optical lattice. We explore the dynamics, looking for signatures of ballistic, diffusive, and localized behavior as a function of the types and strength of disorder applied.

  2. Thermal ionization of Cs Rydberg states

    NASA Astrophysics Data System (ADS)

    Glukhov, I. L.; Ovsiannikov, V. D.

    2009-01-01

    Rates Pnl of photoionization from Rydberg ns-, np-, nd-states of a valence electron in Cs, induced by black-body radiation, were calculated on the basis of the modified Fues model potential method. The numerical data were approximated with a three-term expression which reproduces in a simple analytical form the dependence of Pnl on the ambient temperature T and on the principal quantum number n. The comparison between approximate and exactly calculated values of the thermal ionization rate demonstrates the applicability of the proposed approximation for highly excited states with n from 20 to 100 in a wide temperature range of T from 100 to 10,000 K. We present coefficients of this approximation for the s-, p- and d-series of Rydberg states.

  3. Rydberg ensemble based CNOTN gates using STIRAP

    NASA Astrophysics Data System (ADS)

    Gujarati, Tanvi; Duan, Luming

    2016-05-01

    Schemes for implementation of CNOT gates in atomic ensembles are important for realization of quantum computing. We present here a theoretical scheme of a CNOTN gate with an ensemble of three-level atoms in the lambda configuration and a single two-level control atom. We work in the regime of Rydberg blockade for the ensemble atoms due to excitation of the Rydberg control atom. It is shown that using STIRAP, atoms from one ground state of the ensemble can be adiabatically transferred to the other ground state, depending on the state of the control atom. A thorough analysis of adiabatic conditions for this scheme and the influence of the radiative decay is provided. We show that the CNOTN process is immune to the decay rate of the excited level in ensemble atoms. This work is supported by the ARL, the IARPA LogiQ program, and the AFOSR MURI program.

  4. Strong enhancement of Penning ionization for asymmetric atom pairs in cold Rydberg gases: the Tom and Jerry effect

    NASA Astrophysics Data System (ADS)

    Efimov, D. K.; Miculis, K.; Bezuglov, N. N.; Ekers, A.

    2016-06-01

    We consider Penning ionization of Rydberg atom pairs as an Auger-type process induced by the dipole–dipole interaction and employ semiclassical formulae for dipole transitions to calculate the autoionization width as a function of the principal quantum numbers, n d , n i , of both atoms. While for symmetric atom pairs with {n}d={n}i={n}0 the well-known increase of the autoionization width with increasing n 0 is obtained, the result for asymmetric pairs is counterintuitive—for a fixed n i of the ionizing atom of the pair, the autoionization width strongly increases with decreasing n d of the de-excited atom. For H Rydberg atoms this increase reaches two orders of magnitude at the maximum of the n d dependence, and the same type of counterintuitive behavior is exhibited also by Na, Rb and Cs atoms. This is a purely quantum-mechanical effect, which points towards existence of optimal (we call them ‘Tom’ and ‘Jerry’ for ‘big’ and ‘small’) pairs of Rydberg atoms with respect to autoionization efficiency. Building on the model of population redistribution in cold Rydberg gases proposed in [1], we demonstrate that population evolution following the initial laser excitation of Rydberg atoms in state n 0 would eventually lead to the formation of such Tom–Jerry pairs with {n}i\\gt {n}0\\gt {n}d which feature autoionization widths that are enhanced by several orders of magnitude compared to that of two atoms in the initial laser-excited state n 0. We also show that in the high-density regime of cold Rydberg gas experiments the ionization rate of Tom–Jerry pairs can be substantially larger than the blackbody radiation-induced photoionization rate.

  5. Formation of heavy-Rydberg ion-pair states in Rydberg atom collisions with attaching targets

    NASA Astrophysics Data System (ADS)

    Wang, Changhao; Kelley, Michael; Buathong, Sitti; Dunning, F. Barry

    2014-05-01

    Electron transfer in collisions between K(np)Rydberg atoms and electron attaching molecules can lead to formation of heavy-Rydberg ion-pair states comprising a weakly-bound positive-negative ion pair orbiting at large internuclear separations. In the present work ion-pair states are created in a small collision cell and allowed to exit into an analysis region where their binding energy and velocity distributions are determined with the aid of electric-field-induced dissociation and a position sensitive detector. Ion pair production is analyzed using a Monte Carlo collision code that models both the initial Rydberg electron capture and the subsequent behavior of the product ion pair. The data demonstrate that collisions with SF6 and CCl4 lead to formation of long-lived ion pair states with a broad distribution of binding energies whose velocity distribution is strongly peaked in the forward direction. Research supported by the Robert A. Welch Foundation.

  6. Quantum magnetism of alkali Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Malinovskaya, Svetlana; Liu, Gengyuan

    2016-05-01

    We discuss a method to control dynamics in many-body spin states of 87Rb Rydberg atoms. The method permits excitation of cold gases and form ordered structures of alkali atoms. It makes use of a two-photon excitation scheme with circularly polarized and linearly chirped pulses. The method aims for controlled quantum state preparation in large ensembles. It is actual for experiments studding the spin hopping dynamics and realization of quantum random walks.

  7. Microscopic Characterization of Scalable Coherent Rydberg Superatoms

    NASA Astrophysics Data System (ADS)

    Zeiher, Johannes; Schauß, Peter; Hild, Sebastian; Macrı, Tommaso; Bloch, Immanuel; Gross, Christian

    2015-07-01

    Strong interactions can amplify quantum effects such that they become important on macroscopic scales. Controlling these coherently on a single-particle level is essential for the tailored preparation of strongly correlated quantum systems and opens up new prospects for quantum technologies. Rydberg atoms offer such strong interactions, which lead to extreme nonlinearities in laser-coupled atomic ensembles. As a result, multiple excitation of a micrometer-sized cloud can be blocked while the light-matter coupling becomes collectively enhanced. The resulting two-level system, often called a "superatom," is a valuable resource for quantum information, providing a collective qubit. Here, we report on the preparation of 2 orders of magnitude scalable superatoms utilizing the large interaction strength provided by Rydberg atoms combined with precise control of an ensemble of ultracold atoms in an optical lattice. The latter is achieved with sub-shot-noise precision by local manipulation of a two-dimensional Mott insulator. We microscopically confirm the superatom picture by in situ detection of the Rydberg excitations and observe the characteristic square-root scaling of the optical coupling with the number of atoms. Enabled by the full control over the atomic sample, including the motional degrees of freedom, we infer the overlap of the produced many-body state with a W state from the observed Rabi oscillations and deduce the presence of entanglement. Finally, we investigate the breakdown of the superatom picture when two Rydberg excitations are present in the system, which leads to dephasing and a loss of coherence.

  8. Observation of ultralong range Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Shaffer, James

    2009-05-01

    In 1934, Enrico Fermi described the scattering of a low energy electron from a neutral atom by using the ideas of scattering length and pseudopotential. Although the long range potential for an electron-atom interaction is always attractive, Fermi realized that the s-wave scattering length that characterizes the low energy collision can be either positive or negative. For a positive scattering length, the wavefunction of the electron is shifted away from the atom, the electron is repelled; whereas for a negative scattering length, the wavefunction of the electron is shifted to the atom, the electron is attracted. Based on Fermi's approach, Greene and co-workers predicted a novel molecular binding mechanism where a low energy Rydberg electron is scattered from a ground state atom in the case of negative scattering length. In this situation, the interaction between the electron and ground state atom is attractive and results in the formation of bound states of the ground state atom and the Rydberg atom. Molecules bound by electron scattering can have an internuclear separation of several thousand Bohr radii and are very different from molecules formed by 2 Rydberg atoms where the binding is the result of multipolar forces between the atoms alone. In this talk, we present experimental data on the observation of these exotic molecular states for Rb Rydberg atoms in S states for principal quantum numbers n between 34 and 40. The spectroscopic results for the vibrational ground and first excited state of the dimer Rb(5S)-Rb(nS) are presented and the s-wave scattering length for electron-Rb(5S) scattering in the low energy regime where the kinetic energy is less than 100 meV. Finally, we discuss and present data on the lifetimes and decay mechanisms of these molecules in a magnetic trap.

  9. Nonlinear quantum optics mediated by Rydberg interactions

    NASA Astrophysics Data System (ADS)

    Firstenberg, O.; Adams, C. S.; Hofferberth, S.

    2016-08-01

    By mapping the strong interaction between Rydberg excitations in ultra-cold atomic ensembles onto single photons via electromagnetically induced transparency, it is now possible to realize a medium which exhibits a strong optical nonlinearity at the level of individual photons. We review the theoretical concepts and the experimental state-of-the-art of this exciting new field, and discuss first applications in the field of all-optical quantum information processing.

  10. Cold Rydberg atoms in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Guest, J. R.; Choi, J.-H.; Povilus, A.; Raithel, G.

    2003-05-01

    The combination of laser-cooling and trapping methods with Rydberg-atom spectroscopy has opened the door to the study of novel ultracold atomic and plasma systems. In particular, the study of Rydberg atoms in strong magnetic fields, which has previously been restricted to optically accessible low azimuthal quantum numbers |m|, has been expanded to include high azimuthal quantum numbers |m| through new collisional and recombinative processes which can play a role in this regime. We describe our efforts to realize this new regime experimentally with a superconducting atom and plasma trap. In theoretical work, we have implemented an efficient method to calculate the spectra of Rydberg atoms in strong magnetic fields. We use adiabatic basis sets that reflect the disparate time scales of the electronic motion parallel and transverse to the magnetic field. We find that, with increasing absolute value of |m|, non-adiabatic corrections become negligible, the adiabatic basis states and their energies become exact solutions, and the level statistics evolve from a Wigner to a Possonian distribution of the nearest-neighbor energy separations. The analogy between the adiabatically separable regime of large |m| and the behavior of charged particles in Penning traps will be discussed.

  11. Effective Field Theory for Rydberg Polaritons

    NASA Astrophysics Data System (ADS)

    Gullans, M. J.; Wang, Y.; Thompson, J. D.; Liang, Q.-Y.; Vuletic, V.; Lukin, M. D.; Gorshkov, A. V.

    2016-05-01

    Photons can be made to strongly interact by dressing them with atomic Rydberg states under conditions of electromagnetic induced transparency. Probing Rydberg polaritons in the few-body limit, recent experiments were able to observe non-perturbative two-body effects including: single photon switching and the formation of bound states. Although the two-body problem is amenable to exact solutions, such approaches quickly become intractable for more than two particles. To overcome this problem, we study non-perturbative effects in N-body scattering of Rydberg polaritons using effective field theory (EFT). For attractive interactions, we show how a suitably long medium can be used to prepare shallow N-body bound states in one dimension. We verify this prediction for two and three photons using full numerical simulations. We then consider conditions under which the effective interactions are repulsive and study two and three photon transmission. Finally, we show how to go beyond EFT by measuring the three-body contact force or, alternatively, scattering at high relative momenta.

  12. Slow-light polaritons in Rydberg gases

    NASA Astrophysics Data System (ADS)

    Fleischhauer, Michael

    2012-02-01

    Slow-light polaritons are quasi-particles generated in the interaction of photons with laser-driven atoms with a λ- or ladder-type coupling scheme under conditions of electromagnetically induced transparency (EIT). They are a superposition of electromagnetic and collective spin excitations. If one of the states making up the atomic spin is a high lying Rydberg level, the polaritons are subject to a strong and non-local interaction mediated by a dipole-dipole or van-der Waals coupling between excited Rydberg atoms. I will present and discuss an effective many-body model for these Rydberg polaritons. Depending on the detuning of the control laser the interaction potential between the polaritons can be repulsive or attractive and can have a large imaginary component for distances less than the so-called blockade radius. The non-local effective interaction gives rize to interesting many-body phenomena such as the generation of photons with an avoided volume, visible in stronlgy suppressed two-particle correlations inside the blockade volume. Moreover the long-range, power-law scaling of the interaction can in the repulsive case give rize to the formation of quasi-crystalline structures of photons. In a one dimensional system the low-energy dynamics of the polaritons can be described in terms of a Luttinger liquid. Using DMRG simulations the Luttinger K parameter is calculated and conditions for the formation of a quasi-crystal are derived. When confined to a two-dimensional geometry, e.g. using a resonator with quasi-degenerate transversal mode spectrum, Rydberg polaritons are an interesting candidate to study the bosonic fractional quantum Hall effect. I will argue that the formation of photons with an avoided volume is essential for explaining recent experiments on stationary EIT in Rydberg gases [1,2].[4pt] [1] J.D. Pritchard et al., Phys. Rev. Lett. 105, 193603 (2010). [0pt] [2] D. Petrosyan, J. Otterbach, and M. Fleischhauer, arXiv:1106.1360

  13. Transport of charge and atomic particles in Rydberg state-rich plasmas

    NASA Astrophysics Data System (ADS)

    Hagström, Magnus; Davidsson, Jan; Holmlid, Leif

    1998-02-01

    New methods make it possible to form considerable flux densities of Rydberg atoms of alkali metals. It is now possible to study the transport processes in regions where the density of Rydberg atoms is large. Examples of such studies have been given by Svensson and coworkers. In the present study, 0022-3727/31/4/013/img1 ions and Rydberg states 0022-3727/31/4/013/img2 are formed by desorption at 1300-1800 K from an Ir surface covered by a thin graphite layer. Due to the very large cross sections for collision processes involving Rydberg species, the Rydberg state-rich plasma between the Ir emitter and a cold grid electrode is not collision free, even at a pressure of 0022-3727/31/4/013/img3 mbar. Electron or 0022-3727/31/4/013/img4 emission takes place from the grid at a rate controlled by the flux of 0022-3727/31/4/013/img1 and 0022-3727/31/4/013/img2. The transition to penetration of 0022-3727/31/4/013/img1 and 0022-3727/31/4/013/img2 through the cloud of excited species between the emitter and grid is observed directly by molecular beam and ion sampling to detectors in a separate chamber. There is a space-charge limited behaviour for the positive current through the plasma as well as, in some modes, a clear positive saturation current, which shows that little gas phase ionization takes place. A current larger than expected from the saturation current as well as maxima in the voltage dependences are observed at high Rydberg densities. These effects are probably caused by space charge compensation due to a dielectric phase of condensed excited species, which means, for example, that the effective distance between the emitter and grid is decreased, as observed. The temperature variation of the space charge limited behaviour gives an activation energy of 0022-3727/31/4/013/img9, while the saturation current gives an activation energy of 0022-3727/31/4/013/img10. This agrees well with the electronic excitations 0022-3727/31/4/013/img11 at 0.90 eV and 0022

  14. Storage enhanced non-linearities in a cold Rydberg ensemble

    NASA Astrophysics Data System (ADS)

    Distante, Emanuele; Padron-Brito, Auxiliadora; Cristiani, Matteo; Paredes-Barato, David; de Riedmatten, Hugues

    2016-05-01

    The possibility to control the interaction between photons provided by highly nonlinear media is a key ingredient to the goal of quantum information processing using photons and a unique tool to study the dynamics of the many-body correlated system. To mediate this interaction, one can exploit electromagnetically induced transparency (EIT) to map the state of the photons into atomic coherence in the form of Rydberg dark-state polaritons. The combination of EIT with the nonlinear interaction between Rydberg atoms provides and effective interaction between photons. By measuring the dynamics of stored Rydberg polaritons, we experimentally demonstrate that storing a probe pulse as Rydberg polaritons strongly enhances the Rydberg mediated interaction compared to the slow-propagation case. We show that the process is characterized by two time scales. We measure a strong enhancement of the interaction at short time scales. By measuring the time-dependent coherence of the stored polariton, we also show that the long time scale dynamics is dominated by Rydberg induced dephasing of the multiparticle components of the state. Our results have a direct consequence in Rydberg quantum optics and enable the test of new theories of strongly interacting Rydberg systems. This work has been funded by: ERC starting Grant QuLIMA, MINECO, Severo Ochoa Grant, AUGAUR and the Europea Union's Horizon 2020.

  15. Spatial correlations between Rydberg atoms in an optical dipole trap

    NASA Astrophysics Data System (ADS)

    Schwarzkopf, A.; Anderson, D. A.; Thaicharoen, N.; Raithel, G.

    2013-12-01

    We use direct spatial ion imaging of cold 85Rb Rydberg atom clouds to measure the Rydberg-Rydberg correlation function, with and without light-shift potentials generated by an optical dipole trap. We find that the blockade radius depends on laser detunings and spatially varying light shifts. At certain laser detunings the probability of exciting Rydberg atoms at particular separations is enhanced, which we interpret to be a result of direct two-photon excitation of Rydberg atom pairs. The results are in accordance with predictions [F. Robicheaux and J. V. Hernández, Phys. Rev. A 72, 063403 (2005), 10.1103/PhysRevA.72.063403] and a model we develop that accounts for a one-dimensional dipole-trap potential.

  16. Simulated quantum process tomography of quantum gates with Rydberg superatoms

    NASA Astrophysics Data System (ADS)

    Beterov, I. I.; Saffman, M.; Yakshina, E. A.; Tretyakov, D. B.; Entin, V. M.; Hamzina, G. N.; Ryabtsev, I. I.

    2016-06-01

    We have numerically simulated quantum tomography of single-qubit and two-qubit quantum gates with qubits represented by mesoscopic ensembles containing random numbers of atoms. Such ensembles of strongly interacting atoms in the regime of Rydberg blockade are known as Rydberg superatoms. The stimulated Raman adiabatic passage (STIRAP) in the regime of Rydberg blockade is used for determining Rydberg excitation in the ensemble, required for the storage of quantum information in the collective state of the atomic ensemble and implementation of two-qubit gates. The optimized shapes of the STIRAP pulses are used to achieve high fidelity of the population transfer. Our simulations confirm the validity and high fidelity of single-qubit and two-qubit gates with Rydberg superatoms.

  17. Rydberg Electrons in a Bose-Einstein Condensate.

    PubMed

    Wang, Jia; Gacesa, Marko; Côté, R

    2015-06-19

    We investigate a hybrid system composed of ultracold Rydberg atoms immersed in an atomic Bose-Einstein condensate (BEC). The coupling between Rydberg electrons and BEC atoms leads to excitations of phonons, the exchange of which induces a Yukawa interaction between Rydberg atoms. Because of the small electron mass, the effective charge associated with this quasiparticle-mediated interaction can be large. Its range, equal to the BEC healing length, is tunable using Feshbach resonances to adjust the scattering length between BEC atoms. We find that for small healing lengths, the distortion of the BEC can "image" the Rydberg electron wave function, while for large healing lengths the induced attractive Yukawa potentials between Rydberg atoms are strong enough to bind them. PMID:26196974

  18. Microwave observations of the dipole-dipole interaction between cold Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Afrousheh, K.; Bohlouli, P. Z.; Vagale, D.; Fedorov, M.; Mugford, A.; Martin, J. D. D.

    2004-05-01

    Neighboring Rydberg atoms may strongly interact through electric dipole-dipole couplings. Thus, temporary excitation to Rydberg states has been proposed for implementing elements of quantum information processing using cold neutral atoms. In this work we excited Rb atoms in a MOT to the 45d_5/2 Rydberg state. A microwave pulse was then used to transfer a variable amount of 45d_5/2 atoms to the 46p_3/2 state. Atoms in the 45d and 46p states strongly interact through an always resonant dipole-dipole interaction. We probe this by introducing a second microwave pulse which drives the 45d_5/2-46d_5/2 two photon transition. The dipole-dipole interaction between 46d and 46p states is relatively weak, so the observed spectra are dominated by the 45d-46p couplings between neighboring atoms. These results are discussed in the context of dipole-blockade, as proposed by Lukin et al., Phys. Rev. Lett., 87, 37901 (2001).

  19. Pulsed Rydberg four-wave mixing with motion-induced dephasing in a thermal vapor

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Hsin; Ripka, Fabian; Löw, Robert; Pfau, Tilman

    2016-01-01

    We report on time-resolved pulsed four-wave mixing (FWM) signals in a thermal Rubidium vapor involving a Rydberg state. We observe FWM signals with dephasing times up to 7 ns, strongly dependent on the excitation bandwidth to the Rydberg state. The excitation to the Rydberg state is driven by a pulsed two-photon transition on ns timescales. Combined with a cw de-excitation laser, a strongly directional and collective emission is generated according to a combination of the phase matching effect and averaging over Doppler classes. In contrast to a previous report (Huber et al. in Phys Rev A 90: 053806, 2014) using off-resonant FWM, at a resonant FWM scheme we observe additional revivals of the signal shortly after the incident pulse has ended. We infer that this is a revival of motion-induced constructive interference between the coherent emissions of the thermal atoms. The resonant FWM scheme reveals a richer temporal structure of the signals, compared to similar, but off-resonant excitation schemes. A simple explanation lies in the selectivity of Doppler classes. Our numerical simulations based on a four-level model including a whole Doppler ensemble can qualitatively describe the data.

  20. Role of ion-pair states in the predissociation dynamics of Rydberg states of molecular iodine.

    PubMed

    von Vangerow, J; Bogomolov, A S; Dozmorov, N V; Schomas, D; Stienkemeier, F; Baklanov, A V; Mudrich, M

    2016-07-28

    Using femtosecond pump-probe ion imaging spectroscopy, we establish the key role of I(+) + I(-) ion-pair (IP) states in the predissociation dynamics of molecular iodine I2 excited to Rydberg states. Two-photon excitation of Rydberg states lying above the lowest IP state dissociation threshold (1st tier) is found to be followed by direct parallel transitions into IP states of the 1st tier asymptotically correlating to a pair of I ions in their lowest states I(+)((3)P2) + I(-)((1)S0), of the 2nd tier correlating to I(+)((3)P0) + I(-)((1)S0), and of the 3rd tier correlating to I(+)((1)D2) + I(-)((1)S0). Predissociation via the 1st tier proceeds presumably with a delay of 1.6-1.7 ps which is close to the vibrational period in the 3rd tier state (3rd tier-mediated process). The 2nd tier IP state is concluded to be the main precursor for predissociation via lower lying Rydberg states proceeding with a characteristic time of 7-8 ps and giving rise to Rydberg atoms I(5s(2)5p(4)6s(1)). The channel generating I((2)P3/2) + I((2)P1/2) atoms with total kinetic energy corresponding to one-photon excitation is found to proceed via a pump - dump mechanism with dramatic change of angular anisotropy of this channel as compared with earlier nanosecond experiments. PMID:27353150

  1. Microwave ionization of Rydberg atoms

    SciTech Connect

    Gallagher, T.F.

    1996-12-31

    An atom can be ionized by a static field if the field depresses the potential below the binding energy W, leading to the requirement E = W{sup 2}/4 in atomic units. The atomic units of field and energy are 5.14 {times} 10{sup 9} V/cm and 27.2 eV. The ionization field is often expressed in terms of the principal quantum number n of the state in question as E = 1/16n{sup 4}. In a microwave field with frequency far less than the separation {Delta}W = 1/n{sup 3} between adjacent n states, atoms other than H ionize at the much lower microwave field amplitude of E = 1/3n{sup 5}. This field corresponds to the Inglis-Teller limit, where it is impossible to resolve spectrally adjacent n states due to Stark broadening in a plasma. In H ionization occurs as it does in a static field. The difference exists because the finite sized ionic core of a non hydrogenic atom breaks one of the symmetries found in H. In non hydrogenic atoms the microwave field drives a series of transitions through successively higher n states culminating in ionization. These transitions can be understood in terms of a Landau-Zener picture based on the variation of the energies of the atoms produced by the time varying field or as the resonant multiphoton absorption of the microwave photons. In either case, the atoms make transitions through real intermediate states en route to ionization. With short, four cycle, microwave pulses complete ionization does not occur with fields of E = 1/3n{sup 5}, and population is left in intermediate states. The transition from ionization at fields near E = 1/3n{sup 5} to fields of E = 1/16n{sup 4} occurs when the frequency becomes low enough that the energies of the states vary adiabatically in the temporally varying field.

  2. Static and dynamic polarizability for C{sup 2+} in Rydberg states

    SciTech Connect

    Stancalie, V.

    2015-07-15

    This work presents results from a non-perturbative calculation of dynamic polarizability of C III ions in 1s{sup 2}2sns ({sup 1}S{sup e}) Rydberg states. We employ a two-state model for dressed atomic states to investigate the effect of the frequency-dependent polarizability of optically dressed 1s{sup 2}2sns({sup 1}S{sup e}) states (n = 5 − 12) on transitions to nearby states (1s{sup 2}2pns({sup 1}P{sub 1}{sup o})). Our model calculation results indicate that the resonance structure of the polarizabilities is entirely captured by the transition terms whereas the free electron polarizability only provides a smooth background. The resonance structure is evident in the plots and the widths increase with increasing principal quantum number. This work refers to highly excited 1s{sup 2}2sns ({sup 1}S) Rydberg states, embedded in the electric dipole field of the 2s – 2p core transition in Li-like C{sup 3+} ion. The contributions of the individual transitions to the static polarizabilities of these Rydberg states are obtained from the use of the sum-over-state method. To this aim, both the C{sup 2+} ground state and the C{sup 3+} target state energies have been carefully calculated based on the configuration interactions method implemented in the General-purpose Relativistic Atomic Structure Package. Agreement is reasonably good with existing data wherever available. These results are believed to be the first such values for this system and will be important for ionic spectroscopy and plasma diagnostics.

  3. Electro-optical properties of Rydberg excitons

    NASA Astrophysics Data System (ADS)

    Zielińska-Raczyńska, Sylwia; Ziemkiewicz, David; Czajkowski, Gerard

    2016-07-01

    We show how to compute the electro-optical functions (absorption, reflection, and transmission) when Rydberg exciton-polaritons appear, including the effect of the coherence between the electron-hole pair and the electromagnetic field. With the use of the real density matrix approach, numerical calculations applied for the Cu2O crystal are performed. We also examine in detail and explain the dependence of the resonance displacement on the state number and applied electric field strength. We report a fairly good agreement with recently published experimental data.

  4. Photon-Photon Interactions via Rydberg Blockade

    SciTech Connect

    Gorshkov, Alexey V.; Otterbach, Johannes; Fleischhauer, Michael; Pohl, Thomas; Lukin, Mikhail D.

    2011-09-23

    We develop the theory of light propagation under the conditions of electromagnetically induced transparency in systems involving strongly interacting Rydberg states. Taking into account the quantum nature and the spatial propagation of light, we analyze interactions involving few-photon pulses. We show that this system can be used for the generation of nonclassical states of light including trains of single photons with an avoided volume between them, for implementing photon-photon gates, as well as for studying many-body phenomena with strongly correlated photons.

  5. Quantum Localization of the Kicked Rydberg Atom

    SciTech Connect

    Yoshida, S.; Reinhold, C. O.; Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6373 ; Burgdoerfer, J.; Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6373; Institute for Theoretical Physics, Vienna University of Technology, A1040 Vienna,

    2000-03-20

    We investigate the quantum localization of the one-dimensional Rydberg atom subject to a unidirectional periodic train of impulses. For high frequencies of the train the classical system becomes chaotic and leads to fast ionization. By contrast, the quantum system is found to be remarkably stable. We find this quantum localization to be directly related to the existence of ''scars'' of the unstable periodic orbits of the system. The localization length is given by the energy excursion along the periodic orbits. (c) 2000 The American Physical Society.

  6. Cold Rydberg atoms in circular states

    NASA Astrophysics Data System (ADS)

    Anderson, David; Schwarzkopf, Andrew; Raithel, Georg

    2012-06-01

    Circular-state Rydberg atoms are interesting in that they exhibit a unique combination of extraordinary properties; long lifetimes (˜n^5), large magnetic moments (l=|m|=n-1) and no first order Stark shift. Circular states have found applications in cavity quantum electrodynamics and precision measurements [1,2], among other studies. In this work we present the production of circular states in an atom trapping apparatus using an adiabatic state-switching method (the crossed-field method [3]). To date, we have observed lifetimes of adiabatically prepared states of several milliseconds. Their relatively large ionization electric fields have been verified by time-of-flight signatures of ion trajectories. We intend to explore the magnetic trapping of circular state Rydberg atoms, as well as their production and interaction properties in ultra-cold and degenerate samples.[4pt] [1] P. Bertet et al., Phys. Rev. Lett., 88, 14 (2002)[0pt] [2] M. Brune et al., Phys. Rev. Lett., 72, 21 (1994)[0pt] [3] D. Delande and J.C. Gay, Europhys. Lett., 5, 303-308 (1988).

  7. RF-dressed Rydberg atoms in hollow-core fibres

    NASA Astrophysics Data System (ADS)

    Veit, C.; Epple, G.; Kübler, H.; Euser, T. G.; Russell, P. St. J.; Löw, R.

    2016-07-01

    The giant electro-optical response of Rydberg atoms manifests itself in the emergence of sidebands in the Rydberg excitation spectrum if the atom is exposed to a radio-frequency (RF) electric field. Here we report on the study of RF-dressed Rydberg atoms inside hollow-core photonic crystal fibres, a system that enables the use of low modulation voltages and offers the prospect of miniaturised vapour-based electro-optical devices. Narrow spectroscopic features caused by the RF field are observed for modulation frequencies up to 500 MHz.

  8. Filtering single atoms from Rydberg-blockaded mesoscopic ensembles

    NASA Astrophysics Data System (ADS)

    Petrosyan, David; Rao, D. D. Bhaktavatsala; Mølmer, Klaus

    2015-04-01

    We propose an efficient method to filter out single atoms from trapped ensembles with unknown numbers of atoms. The method employs stimulated adiabatic passage to reversibly transfer a single atom to the Rydberg state which blocks subsequent Rydberg excitation of all the other atoms within the ensemble. This triggers the excitation of Rydberg-blockaded atoms to short-lived intermediate states and their subsequent decay to untrapped states. Using an auxiliary microwave field to carefully engineer the dissipation, we obtain a nearly deterministic single-atom source. Our method is applicable to small atomic ensembles in individual microtraps and in lattice arrays.

  9. Imaging Spatial Correlations of Rydberg Excitations in Cold Atom Clouds

    SciTech Connect

    Schwarzkopf, A.; Sapiro, R. E.; Raithel, G.

    2011-09-02

    We use direct spatial imaging of cold {sup 85}Rb Rydberg atom clouds to measure the Rydberg-Rydberg correlation function. The results are in qualitative agreement with theoretical predictions [F. Robicheaux and J. V. Hernandez, Phys. Rev. A 72, 063403 (2005)]. We determine the blockade radius for states 44D{sub 5/2}, 60D{sub 5/2}, and 70D{sub 5/2} and investigate the dependence of the correlation behavior on excitation conditions and detection delay. Experimental data hint at the existence of long-range order.

  10. Collisional and Radiative Processes in Adiabatic Deceleration, Deflection, and Off-Axis Trapping of a Rydberg Atom Beam

    SciTech Connect

    Seiler, Ch.; Hogan, S. D.; Schmutz, H.; Agner, J. A.; Merkt, F.

    2011-02-18

    A supersonic beam of Rydberg hydrogen atoms has been adiabatically deflected by 90 deg., decelerated to zero velocity in less than 25 {mu}s, and loaded into an electric trap. The deflection has allowed the suppression of collisions with atoms in the trailing part of the gas pulse. The processes leading to trap losses, i.e., fluorescence to the ground state, and transitions and ionization induced by blackbody radiation have been monitored over several milliseconds and quantitatively analyzed.

  11. Atom-surface studies with Rb Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Chao, Yuanxi; Sheng, Jiteng; Sedlacek, Jonathon; Shaffer, James

    2015-05-01

    We report on experimental and theoretical progress studying atom-surface interactions using rubidium Rydberg atoms. Rydberg atoms can be strongly coupled to surface phonon polariton (SPhP) modes of a dielectric material. The coherent interaction between Rydberg atoms and SPhPs has potential applications for quantum hybrid devices. Calculations of TM-mode SPhPs on engineered surfaces of periodically poled lithium niobate (PPLN) and lithium tantalate (PPLT) for different periodic domains and surface orientations, as well as natural materials such as quartz, are presented. Our SPhP calculations account for the semi-infinite anisotropic nature of the materials. In addition to theoretical calculations, we show experimental results of measurements of adsorbate fields and coupling of Rydberg atoms to SPhPs on quartz.

  12. Borromean three-body FRET in frozen Rydberg gases

    NASA Astrophysics Data System (ADS)

    Faoro, R.; Pelle, B.; Zuliani, A.; Cheinet, P.; Arimondo, E.; Pillet, P.

    2015-09-01

    Controlling the interactions between ultracold atoms is crucial for quantum simulation and computation purposes. Highly excited Rydberg atoms are considered in this prospect for their strong and controllable interactions known in the dipole-dipole case to induce non-radiative energy transfers between atom pairs, similarly to fluorescence resonance energy transfer (FRET) in biological systems. Here we predict few-body FRET processes in Rydberg atoms and observe the first three-body resonance energy transfer in cold Rydberg atoms using cold caesium atoms. In these resonances, additional relay atoms carry away an energy excess preventing the two-body resonance, leading thus to a Borromean type of energy transfer. These few-body processes present strong similarities with multistep FRET between chromophores sometimes called donor-bridge-acceptor or superexchange. Most importantly, they generalize to any Rydberg atom and could lead to new implementations of few-body quantum gates or entanglement.

  13. Borromean three-body FRET in frozen Rydberg gases

    PubMed Central

    Faoro, R.; Pelle, B.; Zuliani, A.; Cheinet, P.; Arimondo, E.; Pillet, P.

    2015-01-01

    Controlling the interactions between ultracold atoms is crucial for quantum simulation and computation purposes. Highly excited Rydberg atoms are considered in this prospect for their strong and controllable interactions known in the dipole-dipole case to induce non-radiative energy transfers between atom pairs, similarly to fluorescence resonance energy transfer (FRET) in biological systems. Here we predict few-body FRET processes in Rydberg atoms and observe the first three-body resonance energy transfer in cold Rydberg atoms using cold caesium atoms. In these resonances, additional relay atoms carry away an energy excess preventing the two-body resonance, leading thus to a Borromean type of energy transfer. These few-body processes present strong similarities with multistep FRET between chromophores sometimes called donor-bridge-acceptor or superexchange. Most importantly, they generalize to any Rydberg atom and could lead to new implementations of few-body quantum gates or entanglement. PMID:26348821

  14. van der Waals explosion of cold Rydberg clusters

    NASA Astrophysics Data System (ADS)

    Faoro, R.; Simonelli, C.; Archimi, M.; Masella, G.; Valado, M. M.; Arimondo, E.; Mannella, R.; Ciampini, D.; Morsch, O.

    2016-03-01

    We report on the direct measurement in real space of the effect of the van der Waals forces between individual Rydberg atoms on their external degrees of freedom. Clusters of Rydberg atoms with interparticle distances of around 5 μ m are created by first generating a small number of seed excitations in a magneto-optical trap, followed by off-resonant excitation that leads to a chain of facilitated excitation events. After a variable expansion time the Rydberg atoms are field ionized, and from the arrival time distributions the size of the Rydberg cluster after expansion is calculated. Our experimental results agree well with a numerical simulation of the van der Waals explosion.

  15. State dependence of Rydberg interaction-induced collisional loss

    NASA Astrophysics Data System (ADS)

    Feng, Zhigang; Zhao, Kejia; Miao, Jingyuan; Li, Difei; Yang, Zhijun; Wu, Zhaochun; He, Zhao; Zhao, Jianming; Jia, Suotang

    2016-09-01

    We present a simple analytical formula from an existing theoretical model and theoretically investigate in detail the state dependence of interaction-induced collisional loss rate coefficients, and the various parameter effects on collisional loss rate. We also investigate the different mechanisms and corresponding effects on collisional loss by analyzing our previous experimental results using the present formula, and even investigate the time evolution of Rydberg atom number for different Rydberg states.

  16. Interactions between Rydberg atoms and ultracold polar molecules

    NASA Astrophysics Data System (ADS)

    Jayaseelan, Maitreyi; Haruza, Marek; Bigelow, Nicholas P.

    2015-05-01

    We investigate dipolar interactions arising in a hybrid system containing both ultracold polar molecules and atomic Rydberg states. Ultracold NaCs molecules are produced by photoassociation from laser cooled mixtures of sodium and cesium atoms and detected through resonant multi-photon ionization (REMPI). Rydberg atoms with large dipole moments are excited in the atomic cloud using a multi-photon process and detected via field-ionization. We look for evidence of the interactions in the observed spectra.

  17. Direct excitation of butterfly states in Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Lippe, Carsten; Niederpruem, Thomas; Thomas, Oliver; Eichert, Tanita; Ott, Herwig

    2016-05-01

    Since their first theoretical prediction Rydberg molecules have become an increasing field of research. These exotic states originate from the binding of a ground state atom in the electronic wave function of a highly-excited Rydberg atom mediated by a Fermi contact type interaction. A special class of long-range molecular states, the butterfly states, were first proposed by Greene et al.. These states arise from a shape resonance in the p-wave scattering channel of a ground state atom and a Rydberg electron and are characterized by an electron wavefunction whose density distribution resembles the shape of a butterfly. We report on the direct observation of deeply bound butterfly states of Rydberg molecules of 87 Rb. The butterfly states are studied by high resolution spectroscopy of UV-excited Rydberg molecules. We find states bound up to - 50 GHz from the 25 P1/2 , F = 1 state, corresponding to binding lengths of 50a0 to 500a0 and with permanent electric dipole moments of up to 500 Debye. This distinguishes the observed butterfly states from the previously observed long range Rydberg molecules in rubidium.

  18. Recent advances in Rydberg physics using alkaline-earth atoms

    NASA Astrophysics Data System (ADS)

    Dunning, F. B.; Killian, T. C.; Yoshida, S.; Burgdörfer, J.

    2016-06-01

    In this brief review, the opportunities that the alkaline-earth elements offer for studying new aspects of Rydberg physics are discussed. For example, the bosonic alkaline-earth isotopes have zero nuclear spin which eliminates many of the complexities present in alkali Rydberg atoms, permitting simpler and more direct comparison between theory and experiment. The presence of two valence electrons allows the production of singlet and triplet Rydberg states that can exhibit a variety of attractive or repulsive interactions. The availability of weak intercombination lines is advantageous for laser cooling and for applications such as Rydberg dressing. Excitation of one electron to a Rydberg state leaves behind an optically active core ion allowing, for high-L states, the optical imaging of Rydberg atoms and their (spatial) manipulation using light scattering. The second valence electron offers the possibility of engineering long-lived doubly excited states such as planetary atoms. Recent advances in both theory and experiment are highlighted together with a number of possible directions for the future.

  19. Optical properties of Rydberg excitons and polaritons

    NASA Astrophysics Data System (ADS)

    Zielińska-Raczyńska, Sylwia; Czajkowski, Gerard; Ziemkiewicz, David

    2016-02-01

    We show how to compute the optical functions when Rydberg excitons appear, including the effect of the coherence between the electron-hole pair and the electromagnetic field. We use the real density matrix approach (RDMA), which, combined with the Green's function method, enables one to derive analytical expressions for the optical functions. Choosing the susceptibility, we performed numerical calculations appropriate to a Cu20 crystal, being a semiconductor with an indirect gap. The effect of the coherence is displayed in the line shape. We also examine in detail and explain the dependence of the oscillator strength and the resonance placement on the state number. We report good agreement with recently published experimental data. We also show that the presented method can be applied to semiconductors with a direct gap.

  20. Electron capture from circular Rydberg atoms

    SciTech Connect

    Hansen, S.B.; Ehrenreich, T.; Horsdal-Pedersen, E. ); MacAdam, K.B. ); Dube, L.J. )

    1993-09-06

    Capture cross sections for circular Rydberg states have been measured as a function of the angle, [ital cphi], between ion velocity and angular momentum of the circular orbital. The system studied is 2.5 keV [sup 23]Na[sup +] on Li(1[ital s][sup 2],[ital nlm]) with [ital n]=25, [ital l]=[ital n][minus]1, and [ital m]=+[ital l], where [ital m] is defined relative to a weak, external magnetic field. A strong dependence on [ital cphi] is found. It is expected that studies such as the present will lead to an improved understanding of the three-body problem in the region of sufficiently large quantum numbers and impact velocities for classical physics to be accurate.

  1. A Rydberg impurity in a dense background gas (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Liebisch, Tara; Schlagmüller, Michael; Engel, Felix; Westphal, Karl; Kleinbach, Kathrin; Böttcher, Fabian; Loew, Robert; Hofferberth, Sebastian; Pfau, Tilman; Perez-Rios, Jesus; Greene, Chris

    2016-04-01

    A single Rydberg atom impurity excited in a BEC is a system that can be utilized to measure the quantum mechanical properties of electron - neutral scattering andthe electron probability density of a Rydberg atom. The Rydberg electron - neutral atom scattering process, is a fundamental scattering process, which can be described via Fermi's pseudopotential as V{ěc{r},ěc{R} )=2pi {a}[k(R)]&delta^{(3)}(ěc{r}-ěc{R}). The scattering length is dependent on the momentum of the Rydberg electron, and therefore is dependent on the separation of the Rydberg electron from the ion core. At the classical outermost turning point of the electron, it has the slowest momentum leading to s-wave dominated scattering potentials 10's of MHz in depth for n<40 (Greene et al. PRL 85 2458 (2000), Bendkowsky et al. PRL 105 163201 (2010)). In alkali atoms there is a shape resonance for p-wave scattering, which becomes relevant at ion-neutral separations of 75nm (I.I. Fabrikant J.Phys B 19, 1527 (1985)). This shape resonance potential is several GHz deep, spanning the energy level spacing between n and n-1 principal quantum numbers. At high BEC densities of 5x10^14cm-3 the nearest neighbor spacing is less than 70nm. A Rydberg atom excited within a BEC, is an excitation of the Rydberg atom and all N neutral atoms located within the Rydberg orbit, described as nS+N x 5S. The nS+N x 5S state is density shifted from the Rydberg resonance. Not only does the distribution of atoms within the Rydberg orbit lead to a density shift, but, at these high densities, atoms excited in the nS+N x 5S state near the shape resonance potential cause large perturbations to the density shift, leading to a line broadening. Therefore the spectroscopic line shape of a Rydberg atom in a BEC allows us to probe the theoretically calculated p-wave shape resonance potential. Furthermore, we can observe and measure the dynamics of neutrals excited in the nS+N x 5S state. In the ultracold regime of a BEC, the background

  2. Valence and lowest Rydberg electronic states of phenol investigated by synchrotron radiation and theoretical methods.

    PubMed

    Limão-Vieira, P; Duflot, D; Ferreira da Silva, F; Lange, E; Jones, N C; Hoffmann, S V; Śmiałek, M A; Jones, D B; Brunger, M J

    2016-07-21

    We present the experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectra of phenol covering for the first time the full 4.3-10.8 eV energy-range, with absolute cross sections determined. Theoretical calculations on the vertical excitation energies and oscillator strengths were performed using time-dependent density functional theory and the equation-of-motion coupled cluster method restricted to single and double excitations level. These have been used in the assignment of valence and Rydberg transitions of the phenol molecule. The VUV spectrum reveals several new features not previously reported in the literature, with particular reference to the 6.401 eV transition, which is here assigned to the 3sσ/σ(∗)(OH)←3π(3a″) transition. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of phenol in the earth's atmosphere (0-50 km). PMID:27448882

  3. Valence and lowest Rydberg electronic states of phenol investigated by synchrotron radiation and theoretical methods

    NASA Astrophysics Data System (ADS)

    Limão-Vieira, P.; Duflot, D.; Ferreira da Silva, F.; Lange, E.; Jones, N. C.; Hoffmann, S. V.; Śmiałek, M. A.; Jones, D. B.; Brunger, M. J.

    2016-07-01

    We present the experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectra of phenol covering for the first time the full 4.3-10.8 eV energy-range, with absolute cross sections determined. Theoretical calculations on the vertical excitation energies and oscillator strengths were performed using time-dependent density functional theory and the equation-of-motion coupled cluster method restricted to single and double excitations level. These have been used in the assignment of valence and Rydberg transitions of the phenol molecule. The VUV spectrum reveals several new features not previously reported in the literature, with particular reference to the 6.401 eV transition, which is here assigned to the 3sσ/σ∗(OH)←3π(3a″) transition. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of phenol in the earth's atmosphere (0-50 km).

  4. Transitions.

    ERIC Educational Resources Information Center

    Nathanson, Jeanne H., Ed.

    1993-01-01

    This theme issue on transitions for individuals with disabilities contains nine papers discussing transition programs and issues. "Transition Issues for the 1990s," by Michael J. Ward and William D. Halloran, discusses self-determination, school responsibility for transition, continued educational engagement of at-risk students, and service…

  5. Pipkin Award Talk: Rydberg Charge Exchange: A Method for Producing Rydberg Positronium and Antihydrogen Atoms

    NASA Astrophysics Data System (ADS)

    Hessels, E. A.

    2003-05-01

    Antihydrogen production via two-stage charge exchange(E.A.Hessels, D.M. Homan and M.J. Cavagnero, Phys. Rev. A. 57), (1998) 1668. may provide extremely cold antimatter atoms that can be trapped for spectroscopic studies. Positrons(J. Estrada, T. Roach, J.N. Tan, P. Yesley, and G. Gabrielse, Phys. Rev. Lett. 84), (2000) 859. and antiprotons(G. Gabrielse, N. S. Bowden, P. Oxley, A. Speck, C. H. Storry, J. N. Tan, M. Wessels, D. Grozonka, W. Oelert, G. Schepers, T. Sefzick, J. Walz, H. Pittner, T. W. Hansch, E. A. Hessels, Phys. Lett. B 548), (2002) 140-145., both cooled to 4 K and loaded into adjacent wells of a Penning trap, provide the basic components. Laser-excited Rydberg cesium atoms are passed through the cloud of trapped positrons and charge exchange with the positrons to form Rydberg states of positronium. These positronium atoms have been observed and are studied by ionizing them and counting the resulting positrons. State analysis of the positronium is obtained by varying the electric field used to ionize the atoms. Large numbers of positronium atoms are produced and their binding energies are found to be similar to that of the incoming Rydberg cesium atoms. A second charge exchange is proposed, in which the neutral positronium travels a short distance to an adjacent antiproton cloud. The result of this second charge exchange would be antihydrogen atoms. The apparatus to test this second charge exchange has already been constructed and preliminary studies have already been made.

  6. Blackbody-induced decay, excitation and ionization rates for Rydberg states in hydrogen and helium atoms

    NASA Astrophysics Data System (ADS)

    Glukhov, I. L.; Nekipelov, E. A.; Ovsiannikov, V. D.

    2010-06-01

    New features of the blackbody-induced radiation processes on Rydberg atoms were discovered on the basis of numerical data for the blackbody-induced decay Pdnl(T), excitation Penl(T) and ionization Pionnl(T) rates of nS, nP and nD Rydberg states calculated together with the spontaneous decay rates Pspnl in neutral hydrogen, and singlet and triplet helium atoms for some values of the principal quantum number n from 10 to 500 at temperatures from T = 100 K to 2000 K. The fractional rates Rd(e, ion)nl(T) = Pnld(e, ion)(T)/Pspnl equal to the ratio of the induced decay (excitation, ionization) rates to the rate of spontaneous decay were determined as functions of T and n in every series of states with a given angular momentum l = 0, 1, 2. The calculated data reveal an essential difference between the asymptotic dependence of the ionization rate Pionnl(T) and the rates of decay and excitation Pd(e)nl(T)~T/n2. The departures appear in each Rydberg series for n > 100 and introduce appreciable corrections to the formula of Cooke and Gallagher. Two different approximation formulae are proposed on the basis of the numerical data, one for Rd(e)nl(T) and another one for Rionnl(T), which reproduce the calculated values in wide ranges of principal quantum number from n = 10 to 1000 and temperatures between T = 100 K and T = 2000 K with an accuracy of 2% or better. Modified Fues' model potential approach was used for calculating matrix elements of bound-bound and bound-free radiation transitions in helium.

  7. Detection of precise quantum defects of the 6snd, 6sng and 6sni Rydberg states of Ytterbium

    NASA Astrophysics Data System (ADS)

    Niyaz, Fathima; Nunkaew, Jirakan; Gallagher, Thomas

    2016-05-01

    We use a selective field ionization technique to observe the microwave transitions of Ytterbium Rydberg states, from the 6s(n + 3)d states to the 6sng and 6snh states for 27 <= n <= 33. We also observe the microwave transitions from 6snd to 6s(n + 1)d for states 33 <= n <= 38. Our measurements and previous 6snd to 6s(n + 1)d measurements give precise values for the 6snd quantum defects which indicate the presence of a previously undetected perturbation in the series. This work has been supported by the U. S. Department of Energy, Office of Basic Energy Sciences.

  8. Analysis of High-n Dielectronic Rydberg Satellites in the Spectra of Na-like ZnXX and Mg-like ZnXIX

    SciTech Connect

    Petrocelli, G; Vinogradov, V I; Magunov, A I; Flora, F; Martellucci, S; Matafonov, A P; DiLazzaro, P; Skobelev, I Y; Pikuz, T A; Kyrilov, A S; Faenov, A Y; Francucci, M; Fournier, K B; Murra, D; Belyaev, V S; Bollanti, S

    2004-02-19

    We have observed spectra from highly charged zinc ions in a variety of laser-produced plasmas. Spectral features that are Na- and Mg-like satellites to high-n Rydberg transitions in the Ne-like ZnXXI spectrum are analyzed and modeled. Identifications and analysis are made by comparison with highly accurate atomic structure calculations and steady state collisional-radiative models. Each observed ZnXX and ZnXIX feature comprises up to {approx} 2 dozen individual transitions, these transitions are excited principally by dielectronic recombination through autoionizing levels in Na- and Mg-like Zn{sup 19+} Zn{sup 18+}. We find these satellites to be ubiquitous in laser-produced plasmas formed by lasers with pulse lengths that span four orders of magnitude, from 1 ps to {approx} 10 ns. The diagnostic potential of these Rydberg satellite lines is demonstrated.

  9. Lifetimes of ultra-long-range strontium Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Camargo, F.; Whalen, J. D.; Ding, R.; Sadeghpour, H. R.; Yoshida, S.; Burgdorfer, J.; Dunning, F. B.; Killian, T. C.

    2016-05-01

    The lifetimes of the lower-lying vibrational states of ultralong-range strontium Rydberg molecules comprising one ground-state 5s2 1S0 atom and one Rydberg atom in the 5s 38s3S1 state are reported. The molecules are created in an ultracold gas held in an optical dipole trap and their numbers determined using field ionization, the product electrons being detected by a microchannel plate. The measurements show that, in marked contrast to earlier measurements involving rubidium Rydberg molecules, the lifetimes of the low-lying molecular vibrational states are very similar to those of the parent Rydberg atoms. This results because the strong p-wave resonance in low-energy electron-rubidium scattering, which strongly influences the rubidium molecular lifetimes, is not present for strontium. The absence of this resonance offers advantages for experiments involving strontium Rydberg atoms as impurities in quantum gases and for testing theories of molecular formation and decay. This research was supported by the AFOSR, NSF, the Robert A. Welch Foundation, the FWF (Austria), FWF-SFB049 NextLite. H.R.S. was supported by a Grant to ITAMP from the NSF.

  10. Phase diagram of Rydberg atoms with repulsive van der Waals interaction

    SciTech Connect

    Osychenko, O. N.; Astrakharchik, G. E.; Boronat, J.; Lutsyshyn, Y.; Lozovik, Yu. E.

    2011-12-15

    We report a quantum Monte Carlo calculation of the phase diagram of bosons interacting with a repulsive inverse sixth power pair potential, a model for assemblies of Rydberg atoms in the local van der Waals blockade regime. The model can be parametrized in terms of just two parameters, the reduced density and temperature. Solidification happens to the fcc phase. At zero temperature, the transition density is found with the diffusion Monte Carlo method at density {rho}=3.9 (({Dirac_h}/2{pi}){sup 2}/mC{sub 6}){sup 3/4}, where C{sub 6} is the strength of the interaction. The solidification curve at nonzero temperature is studied with the path-integral Monte Carlo approach and is compared with transitions in corresponding harmonic and classical crystals. Relaxation mechanisms are considered in relation to present experiments.

  11. Lifetimes of Heavy-Rydberg Ion-Pair States Formed through Rydberg Electron Transfer

    SciTech Connect

    Cannon, M.; Wang, C. H.; Dunning, F. B.; Reinhold, Carlos O

    2010-01-01

    The lifetimes of K{sup +}-Cl{sup -}, K{sup +}-CN{sup -}, and K{sup +}-SF{sub 6}{sup -} heavy-Rydberg ion-pair states produced through Rydberg electron transfer reactions are measured directly as a function of binding energy using electric field induced detachment and the ion-pair decay channels discussed. The data are interpreted using a Monte Carlo collision code that models the detailed kinematics of electron transfer reactions. The lifetimes of K{sup +}-Cl{sup -} ion-pair states are observed to be very long, >100 {micro}s, and independent of binding energy. The lifetimes of strongly bound (>30 meV) K{sup +}-CN{sup -} ion pairs are found to be similarly long but begin to decrease markedly as the binding energy is reduced below this value. This behavior is attributed to conversion of rotational energy in the CN{sup -} ion into translational energy of the ion pair. No long-lived K{sup +}-SF{sub 6}{sup -} ion pairs are observed, their lifetimes decreasing with increasing binding energy. This behavior suggests that ion-pair loss is associated with mutual neutralization as a result of charge transfer.

  12. Vibronic structure and ion core interactions in Rydberg states of diazomethane: an experimental and theoretical investigation.

    PubMed

    Fedorov, Igor; Koziol, Lucas; Li, Guosheng; Reisler, Hanna; Krylov, Anna I

    2007-12-27

    Vibronic transitions to the 21A2(3py <-- pi) Rydberg state of CH2N2, CD2N2, and CHDN2 were recorded by 2 + 1 REMPI spectroscopy, and kinetic energy distributions (eKE) of photoelectrons from ionization of selected vibronic levels were determined by velocity map imaging. Normal-mode frequencies were obtained for the 21A2(3py) Rydberg state and for the cation. Mixed levels of the 21A2(3py) and 21B1(3pz) of the three isotopologs were identified by photoelectron imaging and analyzed. The equilibrium geometries and harmonic vibrational frequencies of the electronic states of neutral diazomethane were calculated by CCSD(T)/cc-pVTZ, and B3LYP/6-311G(2df,p). The latter method was also used to calculate isotope shifts for the ground-state neutral and cation. Geometry and frequencies of the ground state of the cation were calculated by CCSD(T)/cc-pVTZ, using the unrestricted (UHF) reference. The equilibrium structures, frequencies, and isotope shifts of the 21A2(3py) and 21B1(3pz) Rydberg states were calculated by EOM-EE-CCSD/6-311(3+,+)G(2df). In all cases where comparisons with experimental results were available, the agreement between theory and experiment was very good allowing a full analysis of trends in structure and vibrational frequencies in going from the neutral species to the excited Rydberg states, 21A2(3py) and 21B1(3pz), and the cation. Although the 21A2(3py) and 21B1(3pz) states have planar C2v symmetry like the ion, they exhibit differences in geometry due to the specific interactions of the electron in the 3py and 3pz orbitals with the nuclei charge distributions of the ion core. Moreover, trends in normal-mode frequencies in the ground states of the neutral and ion and the 21A2(3py) and 21B1(3pz) Rydberg states are consistent with removing an electron from the bonding piCN-orbital, which also has an antibonding character with respect to NN. To explain the observed trends, the vibrational modes are divided into two groups that involve displacements mainly

  13. Coherent control of Rydberg states in silicon.

    PubMed

    Greenland, P T; Lynch, S A; van der Meer, A F G; Murdin, B N; Pidgeon, C R; Redlich, B; Vinh, N Q; Aeppli, G

    2010-06-24

    Laser cooling and electromagnetic traps have led to a revolution in atomic physics, yielding dramatic discoveries ranging from Bose-Einstein condensation to the quantum control of single atoms. Of particular interest, because they can be used in the quantum control of one atom by another, are excited Rydberg states, where wavefunctions are expanded from their ground-state extents of less than 0.1 nm to several nanometres and even beyond; this allows atoms far enough apart to be non-interacting in their ground states to strongly interact in their excited states. For eventual application of such states, a solid-state implementation is very desirable. Here we demonstrate the coherent control of impurity wavefunctions in the most ubiquitous donor in a semiconductor, namely phosphorus-doped silicon. In our experiments, we use a free-electron laser to stimulate and observe photon echoes, the orbital analogue of the Hahn spin echo, and Rabi oscillations familiar from magnetic resonance spectroscopy. As well as extending atomic physicists' explorations of quantum phenomena to the solid state, our work adds coherent terahertz radiation, as a particularly precise regulator of orbitals in solids, to the list of controls, such as pressure and chemical composition, already familiar to materials scientists. PMID:20577211

  14. Transitions.

    ERIC Educational Resources Information Center

    Field, David; And Others

    1992-01-01

    Includes four articles: "Career Aspirations" (Field); "Making the Transition to a New Curriculum" (Baker, Householder); "How about a 'Work to School' Transition?" (Glasberg); and "Technological Improvisation: Bringing CNC to Woodworking" (Charles, McDuffie). (SK)

  15. Transition.

    ERIC Educational Resources Information Center

    Thompson, Sandy, Ed.; And Others

    1990-01-01

    This "feature issue" focuses on transition from school to adult life for persons with disabilities. Included are "success stories," brief program descriptions, and a list of resources. Individual articles include the following titles and authors: "Transition: An Energizing Concept" (Paul Bates); "Transition Issues for the 1990s" (William Halloran…

  16. Radio-frequency-modulated Rydberg states in a vapor cell

    NASA Astrophysics Data System (ADS)

    Miller, S. A.; Anderson, D. A.; Raithel, G.

    2016-05-01

    We measure strong radio-frequency (RF) electric fields using rubidium Rydberg atoms prepared in a room-temperature vapor cell as field sensors. Electromagnetically induced transparency is employed as an optical readout. We RF-modulate the 60{{{S}}}1/2 and 58{{{D}}}5/2 Rydberg states with 50 and 100 MHz fields, respectively. For weak to moderate RF fields, the Rydberg levels become Stark-shifted, and sidebands appear at even multiples of the driving frequency. In high fields, the adjacent hydrogenic manifold begins to intersect the shifted levels, providing rich spectroscopic structure suitable for precision field measurements. A quantitative description of strong-field level modulation and mixing of S and D states with hydrogenic states is provided by Floquet theory. Additionally, we estimate the shielding of DC electric fields in the interior of the glass vapor cell.

  17. Towards Rydberg quantum optics in a hollow core fiber

    NASA Astrophysics Data System (ADS)

    Noaman, Mohammad; Langbecker, Maria; Windpassinger, Patrick

    2016-05-01

    Cold atoms inside hollow-core fibers present a promising candidate to study strongly coupled light-matter systems. Adding coherent quantum state control and the intriguing features of Rydberg atoms, i.e. long range dipolar interactions leading to a dipole blockade, to the system should allow for the generation of exotic polaritonic and photonic states. This talk will review the current status of our experimental setup where laser cooled Rubidium atoms are transported into a hollow-core fiber. We present the first measurements of Rydberg EIT in the dipole trap in front of the fiber and discuss the progress towards Rydberg physics in a quasi-one-dimensional geometry. This work is supported by FP7, Marie Curie ITN 317485, QTea.

  18. Rydberg blockade effects at n ˜300 in strontium

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Dunning, F. B.; Yoshida, S.; Burgdörfer, J.

    2015-11-01

    Rydberg blockade at n ˜300 , is examined using strontium n F13 Rydberg atoms excited in an atomic beam in a small volume defined by two tightly focused crossed laser beams. The observation of blockade for such states is challenging due to their extreme sensitivity to stray fields and the many magnetic sublevels associated with F states which results in a high local density of states. Nonetheless, with a careful choice of laser polarization to selectively excite only a limited number of these sublevels, sizable blockade effects are observed on an ˜0.1 mm length scale extending blockade measurements into the near-macroscopic regime and enabling study of the dynamics of strongly coupled many-body high-n Rydberg systems under carefully controlled conditions.

  19. Stationary three-dimensional entanglement via dissipative Rydberg pumping

    NASA Astrophysics Data System (ADS)

    Shao, Xiao-Qiang; You, Jia-Bin; Zheng, Tai-Yu; Oh, C. H.; Zhang, Shou

    2014-05-01

    We extend the recent result of a bipartite Bell singlet [A. W. Carr and M. Saffman, Phys. Rev. Lett. 111, 033607 (2013), 10.1103/PhysRevLett.111.033607] to a stationary three-dimensional entanglement between two-individual neutral Rydberg atoms. This proposal makes full use of the coherent dynamics provided by a Rydberg-mediated interaction and the dissipative factor originating from the spontaneous emission of a Rydberg state. The numerical simulation of the master equation reveals that both the target state negativity N (ρ̂∞) and fidelity F (ρ̂∞) can exceed 99.90%. Furthermore, a steady three-atom singlet state |S3> is also achievable based on the same mechanism.

  20. Simplified scheme for entanglement preparation with Rydberg pumping via dissipation

    NASA Astrophysics Data System (ADS)

    Su, Shi-Lei; Guo, Qi; Wang, Hong-Fu; Zhang, Shou

    2015-08-01

    Inspired by recent work [Carr and Saffman, Phys. Rev. Lett. 111, 033607 (2013), 10.1103/PhysRevLett.111.033607], we propose a simplified scheme to prepare the two-atom maximally entangled states via dissipative Rydberg pumping. Compared with the former scheme, the simplified one involves fewer classical laser fields and Rydberg interactions, and the asymmetric Rydberg interactions are avoided. Master equation simulations demonstrate that the fidelity and the Clauser-Horne-Shimony-Holt correlation of the maximally entangled state could reach up to 0.999 and 2.821, respectively, under certain conditions. Furthermore, we extend the physical thoughts to prepare the three-dimensional entangled state, and the numerical simulations show that, in theory, both the fidelity and the negativity of the desired entanglement could be very close to unity under certain conditions.

  1. Three-body interactions between slow light Rydberg polaritons

    NASA Astrophysics Data System (ADS)

    Jachymski, Krzysztof; Bienias, Przemyslaw; Büchler, Hans Peter

    2016-05-01

    Rydberg polaritons have recently emerged as a promising platform for nonlinear optics and photonic quantum simulation. They are created in an atomic medium using electromagnetically induced transparency (EIT) scheme involving a Rydberg excitation. Cavity photons can be used in this context to create long-lived, coherent samples consisting of several polaritons. We show that in addition to effective two-body interaction potential inherited from the Rydberg states, the polaritons also exhibit effective three-body interactions. For attractive two-body forces, the three-body term induces short-range repulsion. We analyze the impact of this interaction on the three-body photonic bound states in one-dimensional geometry and discuss the prospects for engineering novel quantum states.

  2. Magic-wavelength optical traps for Rydberg atoms

    SciTech Connect

    Zhang, S.; Saffman, M.; Robicheaux, F.

    2011-10-15

    We propose blue-detuned optical traps that are suitable for trapping of both ground-state and Rydberg excited atoms. The addition of a background compensation field or a suitable choice of the trap geometry provides a magic trapping condition for ground-state and Rydberg atoms at the trap center. Deviations from the magic condition at finite temperature are calculated. Designs that achieve less than 200-kHz differential trap shift between Cs ground states and 125s Rydberg states for 10 {mu}K Cs atoms are presented. Consideration of the trapping potential and photoionization rates suggests that these traps will be useful for quantum-information experiments with atomic qubits.

  3. Mesoscopic Rydberg Impurity in an Atomic Quantum Gas.

    PubMed

    Schmidt, Richard; Sadeghpour, H R; Demler, E

    2016-03-11

    Giant impurity excitations are powerful probes for exploring new regimes of far out of equilibrium dynamics in few- and many-body quantum systems, and in situ observations of correlations. Motivated by recent experimental progress in spectroscopic studies of Rydberg excitations in ultracold atoms, we develop a new theoretical approach for describing multiscale dynamics of Rydberg excitations in quantum Bose gases. We find that the crossover from few- to many-body dynamics manifests in a dramatic change in spectral profile from resolved molecular lines to broad Gaussian distributions representing a superpolaronic state in which many atoms bind to the Rydberg impurity. We discuss signatures of this crossover in the temperature and density dependence of the spectra. PMID:27015490

  4. Mesoscopic Rydberg Impurity in an Atomic Quantum Gas

    NASA Astrophysics Data System (ADS)

    Schmidt, Richard; Sadeghpour, H. R.; Demler, E.

    2016-03-01

    Giant impurity excitations are powerful probes for exploring new regimes of far out of equilibrium dynamics in few- and many-body quantum systems, and in situ observations of correlations. Motivated by recent experimental progress in spectroscopic studies of Rydberg excitations in ultracold atoms, we develop a new theoretical approach for describing multiscale dynamics of Rydberg excitations in quantum Bose gases. We find that the crossover from few- to many-body dynamics manifests in a dramatic change in spectral profile from resolved molecular lines to broad Gaussian distributions representing a superpolaronic state in which many atoms bind to the Rydberg impurity. We discuss signatures of this crossover in the temperature and density dependence of the spectra.

  5. Crystallization in Ising quantum magnets and Rydberg superatoms

    NASA Astrophysics Data System (ADS)

    Schauss, Peter

    2016-05-01

    Dominating finite-range interactions in many-body systems can lead to intriguing self-ordered phases of matter. For quantum magnets, Ising models with power-law interactions are among the most elementary systems that support such phases. These models can be implemented by laser coupling ensembles of ultracold atoms to Rydberg states. In this talk, I will report on the experimental preparation of crystalline ground states of such spin systems. We observe a magnetization staircase as a function of the system size and show directly the emergence of crystalline states with vanishing susceptibility. Recent results connect these findings with the picture of Rydberg superatoms. We investigated their scalability and observed collective Rabi oscillations with the perspective of using Rydberg superatoms as collective qubits. Experiments performed at Max-Planck Institute of Quantum Optics, Garching, Germany.

  6. Interaction of Rydberg atoms in circular states with the alkaline-earth Ca(4s{sup 2}) and Sr(5s{sup 2}) atoms

    SciTech Connect

    Mironchuk, E. S.; Narits, A. A.; Lebedev, V. S.

    2015-11-15

    The resonant mechanism of interaction of alkaline-earth atoms having a low electron affinity to Rydberg atoms in circular (l = vertical bar m vertical bar = n–1) and near-circular states has been studied. To describe the dynamics of resonant processes accompanied by nonadiabatic transitions between ionic and Rydberg covalent terms of a quasimolecule, an approach based on the integration of coupled equations for the probability amplitudes has been developed taking into account the possibility of the decay of an anion in the Coulomb field of the positive ionic core of a highly excited atom. The approach involves the specific features of the problem associated with the structure of the wavefunction of a Rydberg electron in states with high orbital angular momenta l ∼ n–1. This approach provides a much more accurate description of the dynamics of electronic transitions at collisions between atoms than that within the modified semiclassical Landau–Zener model. In addition, this approach makes it possible to effectively take into account many channels of the problem. The cross sections for resonant quenching of Rydberg states of the Li(nlm) atom with given principal n, orbital l = n–1, and magnetic m quantum numbers at thermal collisions with the Ca(4s{sup 2}) and Sr(5s{sup 2}) atoms have been calculated. The dependences of the results on n, m, and angle α between the relative velocity of the atoms and the normal to the plane of the orbit of the Rydberg electron have been obtained. The influence of orientational effects on the efficiency of the collisional destruction of circular and near-circular states has been studied. The results indicate a higher stability of such states to their perturbations by neutral particles as compared to usually studied nl states with low values of l (l ≪ n)

  7. Interaction of Rydberg atoms in circular states with the alkaline-earth Ca(4 s 2) and Sr(5 s 2) atoms

    NASA Astrophysics Data System (ADS)

    Mironchuk, E. S.; Narits, A. A.; Lebedev, V. S.

    2015-11-01

    The resonant mechanism of interaction of alkaline-earth atoms having a low electron affinity to Rydberg atoms in circular ( l = | m| = n-1) and near-circular states has been studied. To describe the dynamics of resonant processes accompanied by nonadiabatic transitions between ionic and Rydberg covalent terms of a quasimolecule, an approach based on the integration of coupled equations for the probability amplitudes has been developed taking into account the possibility of the decay of an anion in the Coulomb field of the positive ionic core of a highly excited atom. The approach involves the specific features of the problem associated with the structure of the wavefunction of a Rydberg electron in states with high orbital angular momenta l ~ n-1. This approach provides a much more accurate description of the dynamics of electronic transitions at collisions between atoms than that within the modified semiclassical Landau-Zener model. In addition, this approach makes it possible to effectively take into account many channels of the problem. The cross sections for resonant quenching of Rydberg states of the Li( nlm) atom with given principal n, orbital l = n-1, and magnetic m quantum numbers at thermal collisions with the Ca(4 s 2) and Sr(5 s 2) atoms have been calculated. The dependences of the results on n, m, and angle α between the relative velocity of the atoms and the normal to the plane of the orbit of the Rydberg electron have been obtained. The influence of orientational effects on the efficiency of the collisional destruction of circular and near-circular states has been studied. The results indicate a higher stability of such states to their perturbations by neutral particles as compared to usually studied nl states with low values of l ( l ≪ n).

  8. Properties of Th4+ and Th3+ from rf spectroscopy of high-L thorium Rydberg ions

    NASA Astrophysics Data System (ADS)

    Keele, Julie Adel

    Several properties of radon-like Th4+ and francium-like Th3+ were determined from measurements of high-L Rydberg fine structure in Th3+ and Th2+ ions. The measurements were carried out using the resonant excitation Stark ionization spectroscopy (RESIS) technique to detect rf transitions between levels in the same n. The measured Rydberg fine structures were then fit to an effective potential model, and the properties of the ions were extracted. Properties of the 1S0 ground state of Th4+ extracted from the measurements of the n=37 Th3+ Rydberg fine structure were the scalar dipole polarizability, alpha D,0=7.702(6)a.u. and the scalar quadrupole polarizability, alphaQ,0=29.1(1.6) a.u. The Th2+ Rydberg fine structure is much more complex since the ground state of Th3+ is a 2 F5/2, and the presence of low-lying excited states cause non-adiabatic effects in the fine structure which are not well described by the effective potential. To extract the properties, non-adiabatic corrections had to be calculated. The properties of Th3+ extracted were the permanent quadrupole moment, Q=0.5931(14)a.u. , the scalar and tensor dipole polarizabilities, alpha D,0=15.224(33)a.u. and alpha D,2=--5.30(11)a.u., the permanent hexadecapole moment, pi=--0.69(28)a.u., and the reduced dipole and octupole matrix elements coupling the ground state to the 6 d 2D3/2 state, ||=1.436(2) a.u. and ||=3.3(1.1) a.u.

  9. Implementation of chiral quantum optics with Rydberg and trapped-ion setups

    NASA Astrophysics Data System (ADS)

    Vermersch, Benoît; Ramos, Tomás; Hauke, Philipp; Zoller, Peter

    2016-06-01

    We propose two setups for realizing a chiral quantum network, where two-level systems representing the nodes interact via directional emission into discrete waveguides, as introduced in T. Ramos et al. [Phys. Rev. A 93, 062104 (2016), 10.1103/PhysRevA.93.062104]. The first implementation realizes a spin waveguide via Rydberg states in a chain of atoms, whereas the second one realizes a phonon waveguide via the localized vibrations of a string of trapped ions. For both architectures, we show that strong chirality can be obtained by a proper design of synthetic gauge fields in the couplings from the nodes to the waveguide. In the Rydberg case, this is achieved via intrinsic spin-orbit coupling in the dipole-dipole interactions, while for the trapped ions it is obtained by engineered sideband transitions. We take long-range couplings into account that appear naturally in these implementations, discuss useful experimental parameters, and analyze potential error sources. Finally, we describe effects that can be observed in these implementations within state-of-the-art technology, such as the driven-dissipative formation of entangled dimer states.

  10. Non-Markovian dynamics in ultracold Rydberg aggregates

    NASA Astrophysics Data System (ADS)

    Genkin, M.; Schönleber, D. W.; Wüster, S.; Eisfeld, A.

    2016-07-01

    We propose a setup of an open quantum system in which the environment can be tuned such that either Markovian or non-Markovian system dynamics can be achieved. The implementation uses ultracold Rydberg atoms, relying on their strong long-range interactions. Our suggestion extends the features available for quantum simulators of molecular systems employing Rydberg aggregates and presents a new test bench for fundamental studies of the classification of system–environment interactions and the resulting system dynamics in open quantum systems.

  11. Three-Body Interaction of Rydberg Slow-Light Polaritons

    NASA Astrophysics Data System (ADS)

    Jachymski, Krzysztof; Bienias, Przemysław; Büchler, Hans Peter

    2016-07-01

    We study a system of three photons in an atomic medium coupled to Rydberg states near the conditions of electromagnetically induced transparency. Based on the analytical analysis of the microscopic set of equations in the far-detuned regime, the effective three-body interaction for these Rydberg polaritons is derived. For slow light polaritons, we find a strong three-body repulsion with the remarkable property that three polaritons can become essentially noninteracting at short distances. This analysis allows us to derive the influence of the three-body repulsion on bound states and correlation functions of photons propagating through a one-dimensional atomic cloud.

  12. Spatial Patterns in Rydberg Excitations from Logarithmic Pair Interactions.

    PubMed

    Lechner, Wolfgang; Zoller, Peter

    2015-09-18

    The collective excitations in ensembles of dissipative, laser driven ultracold atoms exhibit crystal-like patterns, a many-body effect of the Rydberg blockade mechanism. These crystalline structures are revealed in an experiment from a postselection of configurations with fixed numbers of excitations. Here, we show that these subensembles can be well represented by ensembles of effective particles that interact via logarithmic pair potentials. This allows one to study the emergent patterns with a small number of effective particles to determine the phases of Rydberg crystals and to systematically study contributions from N-body terms. PMID:26430998

  13. Frequency evolution of radiatively assisted collisions of K Rydberg atoms

    SciTech Connect

    Renn, M.J.; Thomson, D.S.; Gallagher, T.F. )

    1994-01-01

    Ramsey interference fringes are observed in the line shape of resonant Rydberg-atom--Rydberg-atom collisions occurring in the presence of a radiation field of frequency comparable to the inverse of the collision time. At low frequencies the fringes are phase dependent, but at high frequencies they are not. We present a theoretical interpretation based on a quasistatic field description which connects the low- and high-frequency regimes. In the high-frequency regime, this model gives results equivalent to those obtained using a dressed-atom'' approach.

  14. Three-Body Interaction of Rydberg Slow-Light Polaritons.

    PubMed

    Jachymski, Krzysztof; Bienias, Przemysław; Büchler, Hans Peter

    2016-07-29

    We study a system of three photons in an atomic medium coupled to Rydberg states near the conditions of electromagnetically induced transparency. Based on the analytical analysis of the microscopic set of equations in the far-detuned regime, the effective three-body interaction for these Rydberg polaritons is derived. For slow light polaritons, we find a strong three-body repulsion with the remarkable property that three polaritons can become essentially noninteracting at short distances. This analysis allows us to derive the influence of the three-body repulsion on bound states and correlation functions of photons propagating through a one-dimensional atomic cloud. PMID:27517770

  15. Rydberg States of rb and cs Atoms on Helium Nanodroplets: a Rydberg-Ritz Analysis

    NASA Astrophysics Data System (ADS)

    Lackner, Florian; Krois, Gunter; Ernst, Wolfgang E.

    2013-06-01

    Rydberg series of Rb and Cs atoms on the surface of helium nanodroplets (He_{N}) have been studied by resonance enhanced multi-photon ionization spectroscopy and laser induced fluorescence spectroscopy. The recorded excitation spectra are analyzed by using a Rydberg-Ritz approach. The dependence of the quantum defects on the principal quantum number within a Rydberg series gives insight into the interaction between the alkali atom's valence electron and the superfluid helium droplet. For higher excited states a screening of the valence electron from the alkali atom core by the helium droplet is observed. For lower states the strength of the screening effect decreases and the quantum defects are found to lie closer to free atom values. In addition, the large spin-orbit (SO) constant of the Cs-He_{N} nP(^{2}Π) states allows a detailed study of the influence of the helium droplet on the SO splitting as function of the principal quantum number. Within the pseudo-diatomic picture the alkali-He_{N} system represents a diatomic molecule. The coupling of the Cs valence electrons spin and the orbital angular momentum with the intermolecular axis, which is defined by the connection between the droplet center and the alkali nucleus, depends on the strength of the atomic SO interaction. While the splitting of the 6^{2}P_{1/2}(^{2}Π_{1/2}) and 6^{2}P_{3/2}(^{2}Π_{3/2}) components has an atom-like character (Hund's case (c) coupling), the SO splitting of higher n states is lower than the atomic value (Hund's case (a) coupling). C. Callegari and W. E. Ernst, Helium Droplets as Nanocryostats for Molecular Spectroscopy - from the Vacuum Ultraviolet to the Microwave Regime, in: Handbook of High-Resolution Spectroscopy, eds. M. Quack and F. Merkt, John Wiley & Sons, Chichester, (2011) F. Lackner, G. Krois, M. Theisen, M. Koch, and W.E. Ernst, Phys. Chem. Chem. Phys., 13, 18781-18788 (2011) F. Lackner, G. Krois, and W.E. Ernst, J. Phys. Chem. Lett., 3, 1404-1408 (2012)

  16. Engineered Rydberg Atom-Surface Interactions Using Metamaterials

    NASA Astrophysics Data System (ADS)

    Chao, Yuanxi; Sheng, Jiteng; Sedlacek, Jonathan; Shaffer, James

    2016-05-01

    We report on studies of Rydberg atom-surface interactions aimed at engineering Rydberg atom coupling to metamaterials. Rydberg atoms posses large electric dipole moments that can be strongly coupled to the tightly confined electromagnetic fields of surface phonon polariton (SPhP) modes of a properly constructed piezoelectric superlattice (PSL). Coupling of Rb87 Rydberg atoms, typically in microwave range, to real SPhP resonances on a periodically poled lithium niobate surface is studied theoretically for different periodic domain and surface orientations. Coupling constants, much larger than the dissipation of the atom-surface system, are calculated for atom-surface separations in the near field. This remarkable result opens up a simple way to design and conduct experiments to study the atom-surface interactions in the strong coupling regime which is usually hard to reach in other systems. The light-matter interaction described can be used for a quantum hybrid system that has potential applications for quantum photonic devices. Experimental studies of surfaces showing the efficacy of our calculations are also presented. This work is supported by AFOSR.

  17. A mesoscopic Rydberg impurity in an atomic quantum gas

    NASA Astrophysics Data System (ADS)

    Schmidt, Richard; Sadeghpour, Hossein; Demler, Eugene

    2016-05-01

    Impurity problems have been at the forefront of research in condensed matter physics for several decades. In this talk, we show that Rydberg impurity excitations in ultracold quantum gases present a new frontier in impurity research. Here vastly different energy scales compete, signified in deeply bound Rydberg molecules of mesoscopic size. This situation poses a new challenge for theoretical physics and necessitates the confluence of methods ranging from mesoscopic to atomic physics. In our work, we develop a novel many-body theory for the non-equilibrium dynamics of giant impurity excitations Bose gases. Such single Rydberg impurity excitations have recently been observed, and we demonstrate that the observations can be understood from our theoretical approach which incorporates atomic and many-body theory. The crossover from few-body dynamics to quantum many-body collective behavior - manifest in the appearance of a novel superpolaronic state - is elucidated in our unified functional determinant approach, valid at zero and finite temperature. The time-dependent formalism is not restricted to Rydberg systems but can be generally applied to impurities in bosonic and fermionic environments and opens new possibilities to study impurity dynamics in mesoscopic systems.

  18. Photoionization dynamics of the C2+ ion in Rydberg states

    NASA Astrophysics Data System (ADS)

    Stancalie, Viorica

    2014-11-01

    The goal of this work is to examine in detail the ionization dynamics of Be-like C ion in Rydberg states. An initial calculation has been done to output the lifetime due to spontaneous decay for unperturbed 1s22sns (1Se) Rydberg states using the multi-configuration Dirac-Fock (MCDF) method with configuration interaction option implemented in the general-purpose relativistic atomic structure package (GRASP). Both the C2+ ground state and the C3+ target state energies have been carefully calculated. We report results from a detailed and systematic study of the behaviour of complex photoionization amplitudes, the lifetime due to spontaneous decay for unperturbed 1s22sns (1Se) Rydberg states, the `resonant' phase shift and the rapidly increasing of this shift from well below to well above the resonance position. The sum-over-state method is used to calculate the static dipole polarizability, while the frequency-dependent polarizability values of C2+ ion in these Rydberg states are obtained from two-state model calculation results. Contribution to the Topical Issue "Elementary Processes with Atoms and Molecules in Isolated and Aggregated States", edited by Friedrich Aumayr, Bratislav Marinkovic, Stefan Matejcik, John Tanis and Kurt H. Becker.

  19. Molecular Spectra in an Ultracold Strontium Rydberg Gas

    NASA Astrophysics Data System (ADS)

    Whalen, Joseph D.; Camargo, Francisco; Ding, Roger; Woehl, Germano, Jr.; Dunning, F. Barry; Killian, Thomas C.

    2016-05-01

    The interaction between a ground state atom and a highly excited Rydberg electron creates a potential that can support ultra-long-range bound molecular states comprising a Rydberg atom and several ground-state atoms. We excite these molecular states using two-photon spectroscopy in an ultracold gas of 84 Sr. In a thermal gas, we observe a highly structured spectrum of many-body bound states with one Rydberg atom and as many as three ground-state atoms in various vibrational levels. We also describe the spectrum in a dense, quantum degenerate gas, which is sensitive to the properties of the polaron formed by the binding of many atoms in the quantum gas to the Rydberg impurity. Because of the absence of a p-wave shape resonance in e-Sr scattering, the molecular spectrum in Sr provides a sensitive probe of the excitation dynamics in a quantum gas in a different regime than is accessible using Rb. Research supported by the AFOSR under Grant No. FA9550-14-1-0007, the NSF under Grants No. 1301773 and No. 1205946, the Robert A, Welch Foundation under Grants No. C-0734 and No. C-1844.

  20. Millimeter-wave spectroscopy and multichannel quantum-defect-theory analysis of high Rydberg states of xenon: The hyperfine structure of {sup 129}Xe{sup +} and {sup 131}Xe{sup +}

    SciTech Connect

    Schaefer, Martin; Raunhardt, Matthias; Merkt, Frederic

    2010-03-15

    Millimeter-wave transitions between high-n Rydberg states of several isotopes of xenon have been recorded at sub-megahertz resolution. The fine and, for {sup 129}Xe and {sup 131}Xe, hyperfine structures of s, p, d, and f Rydberg states with principal quantum number in the range 52{<=}n{<=}64 have been determined from combination differences and analyzed using multichannel quantum defect theory. Improved eigenquantum defects and channel interaction parameters for the odd- and even-parity Rydberg states of xenon and the hyperfine structure of the {sup 2}P{sub 3/2} ground state of {sup 129}Xe{sup +} and {sup 131}Xe{sup +} have been obtained. Nearly degenerate p and d fine or hyperfine levels are very easily mixed by even weak stray electric fields.

  1. Collisional and radiative processes in adiabatic deceleration, deflection, and off-axis trapping of a Rydberg atom beam.

    PubMed

    Seiler, Ch; Hogan, S D; Schmutz, H; Agner, J A; Merkt, F

    2011-02-18

    A supersonic beam of Rydberg hydrogen atoms has been adiabatically deflected by 90°, decelerated to zero velocity in less than 25  μs, and loaded into an electric trap. The deflection has allowed the suppression of collisions with atoms in the trailing part of the gas pulse. The processes leading to trap losses, i.e., fluorescence to the ground state, and transitions and ionization induced by blackbody radiation have been monitored over several milliseconds and quantitatively analyzed. PMID:21405512

  2. Wigner-crystallization of Rydberg-Polaritons in the lowest Landau level

    NASA Astrophysics Data System (ADS)

    Grusdt, Fabian; Fleischhauer, Michael

    2012-02-01

    For electrons and dipolar fermions in the lowest Landau level the critical filling for Wigner-crystallization was shown to be νc 1/7 [Baranov et. al., Phys. Rev. Lett. 100 (2008)]. We investigate the fractional quantum Hall effect for Van-der-Waals interacting bosons as realized e.g. by stationary-light polaritons in a Rydberg gas and find no transition to the Wigner crystal (WC). Our numerical studies suggest a crystalline groundstate below ν=1/6 which is expected to be described by a correlated WC of composite quasiparticles. Taking into account a cut-off in the Van-der-Waals interaction we find the WC to be favorable for large cut-offs. Numerical results for different geometries are presented and realistic implementations are discussed.

  3. Radiative and collisional processes in translationally cold samples of hydrogen Rydberg atoms studied in an electrostatic trap

    NASA Astrophysics Data System (ADS)

    Seiler, Ch; Agner, J. A.; Pillet, P.; Merkt, F.

    2016-05-01

    of the magnetic quantum number m than the optically prepared Rydberg–Stark states, and this observation led to the conclusion that a much more efficient mechanism than a purely radiative one must exist to induce transitions to Rydberg–Stark states of higher | m| values. While searching for such a mechanism, we discovered that resonant dipole–dipole collisions between Rydberg atoms in the trap represent an extremely efficient way of inducing transitions to states of higher | m| values. The efficiency of the mechanism is a consequence of the almost perfectly linear nature of the Stark effect at the moderate field strengths used to trap the atoms, which permits cascades of transitions between entire networks of near-degenerate Rydberg-atom-pair states. To include such cascades of resonant dipole–dipole transitions in the numerical simulations, we have generalized the two-state Förster-type collision model used to describe resonant collisions in ultracold Rydberg gases to a multi-state situation. It is only when considering the combined effects of collisional and radiative processes that the observed decay of the population of Rydberg atoms in the trap could be satisfactorily reproduced for all n values studied experimentally.

  4. Direct evidence of three-body interactions in a cold {sup 85}Rb Rydberg gas

    SciTech Connect

    Han Jianing

    2010-11-15

    Cold Rydberg atoms trapped in a magneto-optical trap (MOT) are not isolated and they interact through dipole-dipole and multipole-multipole interactions. First-order dipole-dipole interactions and van der Waals interactions between two atoms have been intensively studied. However, the facts that the first-order dipole-dipole interactions and van der Waals interactions show the same size of broadening [A. Reinhard, K. C. Younge, T. C. Liebisch, B. Knuffman, P. R. Berman, and G. Raithel, Phys. Rev. Lett. 100, 233201 (2008)] and there are transitions between two dimer states [S. M. Farooqi, D. Tong, S. Krishnan, J. Stanojevic, Y. P. Zhang, J. R. Ensher, A. S. Estrin, C. Boisseau, R. Cote, E. E. Eyler, and P. L. Gould, Phys. Rev. Lett. 91, 183002 (2003); K. R. Overstreet, Arne Schwettmann, Jonathan Tallant, and James P. Shaffer, Phys. Rev. A 76, 011403(R) (2007)] cannot be explained by the two-atom picture. The purpose of this article is to show the few-body nature of a dense cold Rydberg gas by studying the molecular-state microwave spectra. Specifically, three-body energy levels have been calculated. Moreover, the transition from three-body energy levels to two-body coupled molecular energy levels and to isolated atomic energy levels as a function of the internuclear spacing is studied. Finally, single-body, two-body, and three-body interaction regions are estimated according to the experimental data. The results reported here provides useful information for plasma formation, further cooling, and superfluid formation.

  5. Direct evidence of three-body interactions in a cold Rb85 Rydberg gas

    NASA Astrophysics Data System (ADS)

    Han, Jianing

    2010-11-01

    Cold Rydberg atoms trapped in a magneto-optical trap (MOT) are not isolated and they interact through dipole-dipole and multipole-multipole interactions. First-order dipole-dipole interactions and van der Waals interactions between two atoms have been intensively studied. However, the facts that the first-order dipole-dipole interactions and van der Waals interactions show the same size of broadening [A. Reinhard, K. C. Younge, T. C. Liebisch, B. Knuffman, P. R. Berman, and G. Raithel, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.100.233201 100, 233201 (2008)] and there are transitions between two dimer states [S. M. Farooqi, D. Tong, S. Krishnan, J. Stanojevic, Y. P. Zhang, J. R. Ensher, A. S. Estrin, C. Boisseau, R. Cote, E. E. Eyler, and P. L. Gould, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.91.183002 91, 183002 (2003); K. R. Overstreet, Arne Schwettmann, Jonathan Tallant, and James P. Shaffer, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.76.011403 76, 011403(R) (2007)] cannot be explained by the two-atom picture. The purpose of this article is to show the few-body nature of a dense cold Rydberg gas by studying the molecular-state microwave spectra. Specifically, three-body energy levels have been calculated. Moreover, the transition from three-body energy levels to two-body coupled molecular energy levels and to isolated atomic energy levels as a function of the internuclear spacing is studied. Finally, single-body, two-body, and three-body interaction regions are estimated according to the experimental data. The results reported here provides useful information for plasma formation, further cooling, and superfluid formation.

  6. From molecular spectra to a density shift in dense Rydberg gases

    PubMed Central

    Gaj, A.; Krupp, A. T.; Balewski, J. B.; Löw, R.; Hofferberth, S.; Pfau, T.

    2014-01-01

    In Rydberg atoms, at least one electron is excited to a state with a high principal quantum number. In an ultracold environment, this low-energy electron can scatter off a ground state atom allowing for the formation of a Rydberg molecule consisting of one Rydberg atom and several ground state atoms. Here we investigate those Rydberg molecules created by photoassociation for the spherically symmetric S-states. A step by step increase of the principal quantum number up to n=111 enables us to go beyond the previously observed dimer and trimer states up to a molecule, where four ground state atoms are bound by one Rydberg atom. The increase of bound atoms and the decreasing binding potential per atom with principal quantum number results finally in an overlap of spectral lines. The associated density-dependent line broadening sets a fundamental limit, for example, for the optical thickness per blockade volume in Rydberg quantum optics experiments. PMID:25082599

  7. Transfer of entangled state, entanglement swapping and quantum information processing via the Rydberg blockade

    NASA Astrophysics Data System (ADS)

    Deng, Li; Chen, Ai-Xi; Zhang, Jian-Song

    2011-11-01

    We provide a scheme with which the transfer of the entangled state and the entanglement swapping can be realized in a system of neutral atoms via the Rydberg blockade. Our idea can be extended to teleport an unknown atomic state. According to the latest theoretical research of the Rydberg excitation and experimental reports of the Rydberg blockade effect in quantum information processing, we discuss the experimental feasibility of our scheme.

  8. Medium and high resolution vacuum UV photoabsorption spectroscopy of methyl iodide (CH 3I) and its deuterated isotopomers CD 3I and CH 2DI. A Rydberg series analysis

    NASA Astrophysics Data System (ADS)

    Locht, R.; Leyh, B.; Jochims, H. W.; Baumgärtel, H.

    2009-11-01

    The vacuum UV photoabsorption spectrum of CH 3I has been investigated between 5 eV and 20 eV. Numerous vibronic transitions are observed. In the high 10-20 eV photon energy range weak to very weak diffuse bands are observed and ascribed to electronic transitions from 3a 1, 1e and 2a 1 to Rydberg orbitals. In the 6-10.5 eV photon energy range more than 200 sharp and strong to weak lines have been observed. Several photon energy ranges were explored under high resolution conditions allowing us to observe many series up to high values of the principal quantum number n. They are assigned to vibrationless Rydberg transitions and classified into two groups converging to the two components of the spin-orbit split XE state of CH 3I +. These two groups consist of six different Rydberg series, i.e., nsa 1, npa 1, npe, nda 1, nde and nf. A very close correlation has been established between the term values of the Rydberg states in CH 3I and in Xe for ns, np, nd and nf Rydberg transitions. For the first time, the same measurements have been performed and the interpretation has been proposed for the photoabsorption spectrum of CH 2DI and CD 3I in the 6-10.5 eV photon energy range. For these two species, ionization energies are deduced: for the XE 3/2 and XE 1/2 states of CH 2DI, these are IE ad = 9.544 eV and IE ad = 10.168 eV, respectively, and the corresponding energies are 9.552 eV and 10.173 eV in CD 3I.

  9. Measurement of Rydberg atom formation in low-density ultracold neutral plasmas

    NASA Astrophysics Data System (ADS)

    Chen, Wei-Ting; Witte, Craig; Roberts, Jacob

    2016-05-01

    Rydberg atoms are formed in ultracold neutral plasmas primarily through three-body recombination for typical experimental conditions. At low densities the relative importance of electron-Rydberg state-changing collisions in the dynamical evolution of the Rydberg atom state populations is increased, leading to temperature scalings significantly different from the usual T - 9 / 2 scaling associated with the three-body recombination rate. We report our measurement of Rydberg atoms in low-density ultracold neutral plasmas and discuss their utility in calibrating the electron temperature and determining the amount of heating due to continuum lowering that occurs during the formation of the ultracold plasma. This work supported by the AFOSR.

  10. Ultracold Chemical Reactions of a Single Rydberg Atom in a Dense Gas

    NASA Astrophysics Data System (ADS)

    Schlagmüller, Michael; Liebisch, Tara Cubel; Engel, Felix; Kleinbach, Kathrin S.; Böttcher, Fabian; Hermann, Udo; Westphal, Karl M.; Gaj, Anita; Löw, Robert; Hofferberth, Sebastian; Pfau, Tilman; Pérez-Ríos, Jesús; Greene, Chris H.

    2016-07-01

    Within a dense environment (ρ ≈1014 atoms /cm3 ) at ultracold temperatures (T <1 μ K ), a single atom excited to a Rydberg state acts as a reaction center for surrounding neutral atoms. At these temperatures, almost all neutral atoms within the Rydberg orbit are bound to the Rydberg core and interact with the Rydberg atom. We have studied the reaction rate and products for n S 87Rb Rydberg states, and we mainly observe a state change of the Rydberg electron to a high orbital angular momentum l , with the released energy being converted into kinetic energy of the Rydberg atom. Unexpectedly, the measurements show a threshold behavior at n ≈100 for the inelastic collision time leading to increased lifetimes of the Rydberg state independent of the densities investigated. Even at very high densities (ρ ≈4.8 ×1014 cm-3 ), the lifetime of a Rydberg atom exceeds 10 μ s at n >140 compared to 1 μ s at n =90 . In addition, a second observed reaction mechanism, namely, Rb2+ molecule formation, was studied. Both reaction products are equally probable for n =40 , but the fraction of Rb2+ created drops to below 10% for n ≥90 .

  11. Velocity-selective electromagnetically-induced-transparency measurements of potassium Rydberg states

    NASA Astrophysics Data System (ADS)

    Xu, Wenchao; DeMarco, Brian

    2016-01-01

    We demonstrate a velocity selection scheme that mitigates suppression of electromagnetically induced transparency (EIT) by Doppler shifts for coupling wavelengths larger than the probe wavelength. An optical pumping beam counterpropagating with the EIT probe beam transfers atoms between hyperfine states in a velocity-selective fashion. Measurement of the transmitted probe beam synchronous with chopping of the optical pumping beam enables a Doppler-free EIT signal to be detected. Transition frequencies between 5 P1 /2 and n S1 /2 states for n =26 , 27, and 28 in 39K are obtained via EIT spectroscopy in a heated vapor cell with a probe beam stabilized to the 4 S1 /2→5 P1 /2 transition. Using previous high-resolution measurements of the 4 S1 /2→n S1 /2 transitions, we make a determination of the absolute frequency of the 4 S1 /2→5 P1 /2 transition. Our measurement is shifted by 560 MHz from the currently accepted value with a twofold improvement in uncertainty. These measurements will enable novel experiments with Rydberg-dressed ultracold Fermi gases composed of 40K atoms.

  12. Transfer of a weakly bound electron in collisions of Rydberg atoms with neutral particles. I. Long-range interaction effects in the ionic-covalent coupling

    SciTech Connect

    Lebedev, V. S. Narits, A. A.

    2013-10-15

    Ion-pair formation processes are studied in collisions of Rydberg atoms with neutral particles possessing small electron affinities. Nonadiabatic transitions from a Rydberg covalent term to an ionic term of a quasi-molecule are considered using the modified Landau-Zener theory supplemented with calculation of survival factors of an anion decaying in the Coulomb field of a positive ion core. Using the technique of irreducible tensor operators and the momentum representation of the wavefunction of a highly excited atom, exact expressions are obtained for transition matrix elements and the ionic-covalent coupling parameter. The approach developed in the paper provides the description beyond the scope of a conventional assumption about a small variation of the wavefunction of the Rydberg atom on the range of electron coordinates determined by the characteristic radius of the wavefunction of the anion. This allows one to correctly consider long-range effects of the interaction between a weakly bound electron and the neutral core of a negative ion in processes under study. It is shown by the example of thermal collisions of Xe(nf) atoms with CH{sub 3}CN molecules that this is very important for a reliable quantitative description of anion formation with a low binding energy. The results are compared with experiments and calculations performed within the framework of a number of approximate methods.

  13. Observation of the dipole-dipole interaction between cold Rydberg atoms by microwave spectroscopy

    NASA Astrophysics Data System (ADS)

    Park, Hyunwook

    We measured the dipole-dipole interaction between nsnp pairs of atoms by the line broadening technique. The broadening rate relies on the atomic density, equivalently the average internuclear spacing Rav, and principal quantum number n. This measurement of the dipole-dipole broadening can be expressed in terms of n and provides a simple measure of line broadening due to increased atomic density in laboratory units. Calculation of the dipole-dipole interaction was compared to the observations. It was realized that the observations, which have smaller broadening rates than the calculation, stem from the spin-orbit coupling, which results in the shift-free and small-shift dipole-dipole energy levels as well as normal shift levels. As a result of the dipole-dipole interaction, the nsnp molecules form attractive and repulsive dipole-dipole potentials in which atoms are forced to move toward each other and farther apart, respectively. These motions of the atoms in the dipole potentials induce collisional ionization and trigger plasma formation from Rydberg atoms. The collisional ionization was systematically investigated by comparing the effects of the attractive, repulsive, and almost flat potentials. It turned out that atoms transferred to the attractive potential are ionized in a few microseconds, while those on the repulsive potential are not significantly ionized, similar to the flat potential case. Essentially the same result was observed again with an enhanced ion signal by extending the sampling to a broader range of internuclear separation via high microwave power. We also detected plasma fields by using the exaggerated property of Rydberg atoms responding to external electric fields. Rydberg atoms were injected into a plasma cloud, and the ns -- np microwave transition was driven to detect the plasma fields by measuring Stark shifts. We were able to measure a microscopic field as small as 0.1 V/cm. In the presence of a strong macroscopic field, the resonances

  14. Intrinsic optical bistability in a strongly driven Rydberg ensemble

    NASA Astrophysics Data System (ADS)

    de Melo, Natalia R.; Wade, Christopher G.; Šibalić, Nikola; Kondo, Jorge M.; Adams, Charles S.; Weatherill, Kevin J.

    2016-06-01

    We observe and characterize intrinsic optical bistability in a dilute Rydberg vapor. The bistability is characterized by sharp jumps between states of low and high Rydberg occupancy with jump-up and -down positions displaying hysteresis depending on the direction in which the control parameter is changed. We find that the shift in frequency of the jump point scales with the fourth power of the principal quantum number. Also, the width of the hysteresis window increases with increasing principal quantum number, before reaching a peak and then closing again. The experimental results are consistent with predictions from a simple theoretical model based on semiclassical Maxwell-Bloch equations including the effects of interaction-induced broadening and level shifts. These results provide insight into the dynamics of driven dissipative systems.

  15. Entanglement of Two Individual Neutral Atoms Using Rydberg Blockade

    SciTech Connect

    Wilk, T.; Gaeetan, A.; Evellin, C.; Wolters, J.; Miroshnychenko, Y.; Grangier, P.; Browaeys, A.

    2010-01-08

    We report the generation of entanglement between two individual {sup 87}Rb atoms in hyperfine ground states |F=1,M=1> and |F=2,M=2> which are held in two optical tweezers separated by 4 {mu}m. Our scheme relies on the Rydberg blockade effect which prevents the simultaneous excitation of the two atoms to a Rydberg state. The entangled state is generated in about 200 ns using pulsed two-photon excitation. We quantify the entanglement by applying global Raman rotations on both atoms. We measure that 61% of the initial pairs of atoms are still present at the end of the entangling sequence. These pairs are in the target entangled state with a fidelity of 0.75.

  16. Dynamical Evolution of Interacting Photon Pulses in Rydberg Medium

    NASA Astrophysics Data System (ADS)

    He, Bing; Yang, Liu; Wu, Jin-Hui; Zhang, Zhaoyang; Xiao, Min

    2016-05-01

    We present a study to simulate the absorption and propagation of single photon pulses under their mutual effective interaction in Rydberg atomic ensemble.The study is based on the complete dynamics of the involved quantum fields in Rydberg medium of electromagnetically induced transparency, and considers the tunable control fields to stop and regenerate photon pulses. We find that photons of opposite-sign detunings can have distinct dynamical behaviors when they approach each other. The space-time dependent dissipation of photons under mutual interaction and the passages toward the stopped photons with different control fields are also illustrated in terms of the evolutions of their quantum field profiles. These processes can be applied to implementing various quantum devices such as photon switchers and photon-photon gates.

  17. Entropy and complexity analysis of hydrogenic Rydberg atoms

    SciTech Connect

    Lopez-Rosa, S.; Toranzo, I. V.; Dehesa, J. S.; Sanchez-Moreno, P.

    2013-05-15

    The internal disorder of hydrogenic Rydberg atoms as contained in their position and momentum probability densities is examined by means of the following information-theoretic spreading quantities: the radial and logarithmic expectation values, the Shannon entropy, and the Fisher information. As well, the complexity measures of Cramer-Rao, Fisher-Shannon, and Lopez Ruiz-Mancini-Calvet types are investigated in both reciprocal spaces. The leading term of these quantities is rigorously calculated by use of the asymptotic properties of the concomitant entropic functionals of the Laguerre and Gegenbauer orthogonal polynomials which control the wavefunctions of the Rydberg states in both position and momentum spaces. The associated generalized Heisenberg-like, logarithmic and entropic uncertainty relations are also given. Finally, application to linear (l= 0), circular (l=n- 1), and quasicircular (l=n- 2) states is explicitly done.

  18. Single-Photon Switch Based on Rydberg Blockade

    NASA Astrophysics Data System (ADS)

    Baur, Simon; Tiarks, Daniel; Rempe, Gerhard; Duerr, Stephan

    2015-05-01

    All-optical switching is a technique in which a gate light pulse changes the transmission of a target light pulse without the detour via electronic signal processing. We take this to the quantum regime, where the incoming gate light pulse contains only one photon on average. The gate pulse is stored as a Rydberg excitation in an ultracold atomic gas using electromagnetically induced transparency. Rydberg blockade suppresses the transmission of the subsequent target pulse. Finally, the stored gate photon can be retrieved. A retrieved photon heralds successful storage. The corresponding postselected subensemble shows a relative transmission of 0.05. The single-photon switch offers many interesting perspectives ranging from quantum communication to quantum information processing.

  19. Calculation of Rydberg energy levels for the francium atom

    NASA Astrophysics Data System (ADS)

    Huang, Shi-Zhong; Chu, Jin-Min

    2010-06-01

    Based on the weakest bound electron potential model theory, the Rydberg energy levels and quantum defects of the np2Po1/2 (n = 7-50) and np2Po3/2 (n = 7-50) spectrum series for the francium atom are calculated. The calculated results are in excellent agreement with the 48 measured levels, and 40 energy levels for highly excited states are predicted.

  20. Deterministic entanglement of two neutral atoms via Rydberg blockade

    SciTech Connect

    Zhang, X. L.; Isenhower, L.; Gill, A. T.; Walker, T. G.; Saffman, M.

    2010-09-15

    We demonstrate the deterministic entanglement of two individually addressed neutral atoms using a Rydberg blockade mediated controlled-not gate. Parity oscillation measurements reveal a Bell state fidelity of F=0.58{+-}0.04, which is above the entanglement threshold of F=0.5, without any correction for atom loss, and F=0.71{+-}0.05 after correcting for background collisional losses. The fidelity results are shown to be in good agreement with a detailed error model.

  1. Phases, collective modes, and nonequilibrium dynamics of dissipative Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Ray, S.; Sinha, S.; Sengupta, K.

    2016-03-01

    We use a density matrix formalism to study the equilibrium phases and nonequilibrium dynamics of a system of dissipative Rydberg atoms in an optical lattice within mean-field theory. We provide equations for the fixed points of the density matrix evolution for atoms with infinite on-site repulsion and analyze these equations to obtain their Mott-insulator-superfluid (MI-SF) phase boundary. A stability analysis around these fixed points provides us with the excitation spectrum of the atoms both in the MI and SF phases. We study the nature of the MI-SF critical point in the presence of finite dissipation of Rydberg excitations, discuss the fate of the superfluid order parameter of the atoms in the presence of such dissipation in the weak-coupling limit using a coherent state representation of the density matrix, and extend our analysis to Rydberg atoms with finite on-site interaction via numerical solution of the density matrix equations. Finally, we vary the boson (atom) hopping parameter J and the dissipation parameter Γ according to a linear ramp protocol. We study the evolution of entropy of the system following such a ramp and show that the deviation of the entropy from its steady-state value for the latter protocol exhibits power-law behavior as a function of the ramp time. We discuss experiments that can test our theory.

  2. Rydberg phases of Hydrogen and low energy nuclear reactions

    NASA Astrophysics Data System (ADS)

    Olafsson, Sveinn; Holmlid, Leif

    2016-03-01

    For over the last 26 years the science of cold fusion/LENR has been researched around the world with slow pace of progress. Modest quantity of excess heat and signatures of nuclear transmutation and helium production have been confirmed in experiments and theoretical work has only resulted in a large flora of inadequate theoretical scenarios. Here we review current state of research in Rydberg matter of Hydrogen that is showing strong signature of nuclear processes. In the presentation experimental behavior of Rydberg matter of hydrogen is described. An extensive collaboration effort of surface physics, catalysis, atomic physics, solid state physics, nuclear physics and quantum information is need to tackle the surprising experimental results that have so far been obtained. Rydberg matter of Hydrogen is the only known state of matter that is able to bring huge collection of protons to so short distances and for so long time that tunneling becomes a reasonable process for making low energy nuclear reactions. Nuclear quantum entanglement can also become realistic process at theses conditions.

  3. Progress towards Generating Rydberg State, One Electron Ions

    NASA Astrophysics Data System (ADS)

    Dreiling, Joan; Fogwell Hoogerheide, Shannon; Naing, Aung; Tan, Joseph

    2016-05-01

    We report on progress towards producing hydrogen-like ions in Rydberg states from bare nuclei. Fully stripped neon atoms (Ne10+) are produced by the electron beam ion trap (EBIT) at NIST. These ions are extracted via a beamline from the EBIT into a second apparatus where they are captured at low energy in a unitary Penning trap. The second apparatus has a cross-beam configuration, with a perpendicular beam of laser excited Rb atoms intersecting the ion beam at the Penning trap. While stored in the trap, the ions can interact with the Rb and, through charge exchange interactions, the bare nuclei can capture one or more electrons from the Rb. The ions are then analyzed by dumping the trap to a time-of-flight detector, which allows determination of the ion charge state evolution. This work builds towards laser spectroscopy on hydrogen-like ions in circular Rydberg states to obtain a value for the Rydberg constant independent of nuclear size effects. Such a measurement could shed some light on the proton radius puzzle.

  4. Coherent control of population transfer in Rydberg atoms via chirped microwave pulses.

    PubMed

    Carrera, Juan J; Chu, Shih-I

    2007-09-27

    We present a comprehensive and ab initio nonperturbative investigation of the coherent population transfer among the 3D high-lying Rydberg hydrogen and alkali atomic states via linearly polarized chirped microwave pulses. The time-dependent Schrödinger equation for the dynamical evolution of Rydberg atoms is accurately and efficiently solved by means of the time-dependent generalized pseudospectral method. For atomic H, the population transfer from n = 35 to 30 with nearly 100% efficiency is achieved by means of the sequential two-photon Deltan = -1 transitions. The calculation fully utilizes all of the available orbital angular momentum l states for a given n, and the interference pattern and population evolution dynamics of individual l states are analyzed in detail. It is shown that the coherent control of the population transfer from the high n to the low n states can be accomplished by the optimization of the chirping parameters and microwave field strength. Similar analysis is performed for the Na atom, where the alkali atomic structure is described by an accurate model potential. We found that while the global population transfer pattern is qualitatively similar, there are significant differences in the dynamical response of atomic H and Na to the chirped microwave fields. Due to the degeneracy of the l states (for a given n) in unperturbed atomic H, the population transfer involves significant coupling and interference among a number of low-lying l states. For the case of Na atoms, however, the population transfer from the n to (n - 1) state is dominated by a single channel, namely, from the |n,l = 0> to the |n - 1,l = 0> state. PMID:17722891

  5. The effect of nonpolar solvents on Rydberg states: van der Waals complexes of azabicyclooctanes

    NASA Astrophysics Data System (ADS)

    Shang, Q. Y.; Moreno, P. O.; Dion, C.; Bernstein, E. R.

    1993-05-01

    The effect of solvation by nonpolar solvents on the (n,3s) Rydberg states of 1,4-diazabicyclo[2.2.2]octane (DABCO) and azabicyclo[2.2.2]octane (ABCO) is investigated through mass resolved excitation spectroscopy of their van der Waals complexes. The solute/solvent clusters formed in a supersonic expansion include DABCO and ABCO with Ar, n-CmH2m+2 (m=1-7), and CF4 and C2F6. The resulting spectra are analyzed with the help of empirical potential energy calculations of the cluster binding energies, minimum energy structures, van der Waals modes, and potential barriers between the various cluster minimum energy structures. Good agreement is found between the calculated and experimental results for DABCO and ABCO clustered with argon and methane. The spectra of clusters with all other hydrocarbons can be ascribed to only one major geometry for each cluster stoichiometry, despite the fact that calculations yield many stable geometries for each cluster. This apparent lack of agreement between calculations and experiments can be rationalized based on cluster binding energy, zero point energy, and the potential energy barriers between the cluster minima. The observed blue shift of the cluster 000 transition energy as a function of the n-alkane chain length can be qualitatively modeled by a Lennard-Jones potential for the solute-solvent interaction for both the ground and excited states. The model reveals a strong repulsive interaction between the Rydberg state electronic distribution and the solvent molecule. This repulsion depends on the distance between the solvent molecule and the solute molecule nitrogen atom.

  6. Generation of tunable coherent far-infrared radiation using atomic Rydberg states

    SciTech Connect

    Bookless, W.

    1980-12-01

    A source of tunable far-infrared radiation has been constructed. The system has been operated at 91.6 cm/sup -1/ with a demonstrated tunability of .63 cm/sup -1/. The system is based on a Rydberg state transition in optically pumped potassium vapor. The transition energy is tuned by the application of an electric field to the excited vapor. The transition wavelength and the shifted wavelength were detected and measured by the use of a Michelson interferometer and a liquid helium cooled Ga:Ge bolometer and the data was reduced using Fast Fourier transform techniques. Extensive spectroscopy was done on the potassium vapor to elucidate the depopulation paths and rates of the excited levels. Both theoretical and experimental results are presented to support the conclusions of the research effort. Additionally, possible alternative approaches to the population of the excited state are explored and recommendations are made for the future development of this source as well as the potential uses of it in molecular spectroscopy.

  7. Exploring multiple degrees of freedom in Rydberg wave packets

    NASA Astrophysics Data System (ADS)

    Wen, Haidan

    2006-12-01

    Recent advances in the study of Rydberg atoms have focused on the control, manipulation and detection of Rydberg wave packets using novel external fields such as half-cycle pulses. The radial degree of freedom has been controlled and used to process information encoded in Rydberg states. However, these previous experiments make use of only a single degree of freedom, restricting the potential of other degrees of freedom for quantum computing in Rydberg atoms. In this dissertation, we explore the control and detection of other degrees of freedom in an electron wave packet, such as the angular momentum quantum number ℓ, the magnetic quantum number m and the electron spin; so that the full range of quantum numbers can participate in information processing. We first propose an interferometric control of the population of angular momentum states using two time-delayed phase-locked ultrafast laser pulses. The population of arbitrary angular momentum states can be greatly enhanced by optimizing the time delay and the relative phases between two laser pulses. We then qualitatively measure the evolution of angular momentum components in Stark wave packets by a weak half-cycle pulse (HCP). This measurement utilizes a time-delayed HCP and is proved to be effective for detecting various aspects of wave packet dynamics, particularly, the evolution of non-stationary states. The technique relies on the fact that the HCP redistributes the eigenstate populations and induced the population variation which reflects the evolution of eigenstate phases. Finally, we find that the dynamics of m-states could be highly correlated with the internal degree of freedom of the electron, the spin. We study the effect of spin-orbit coupling on the wave packet dynamics and observe the angular precession of a Rydberg wave packet. The population redistribution from p to s states is highly sensitive to the polarization of the HCP and changes with the precession of the electron orbit. We obtain the

  8. Two experiments with cold atoms: I. Application of Bessel beams for atom optics, and II. Spectroscopic measurements of Rydberg blockade effect

    NASA Astrophysics Data System (ADS)

    Arakelyan, Ilya

    In this dissertation we report the results of two experimental projects with laser-cooled rubidium atoms: I. Application of Bessel beams for atom optics, and II. Spectroscopic measurements of Rydberg blockade effect. The first part of the thesis is devoted to the development of new elements of atom optics based on blue-detuned high-order Bessel beams. Properties of a 4thorder Bessel beam as an atomic guide were investigated for various parameters of the hollow beam, such as the detuning from an atomic resonance, size and the order of the Bessel beam. We extended its application to create more complicated interferometer-type structures by demonstrating a tunnel lock, a novel device that can split an atomic cloud, transport it, delay, and switch its propagation direction between two guides. We reported a first-time demonstration of an atomic beam switch based on the combination of two crossed Bessel beams. We achieved the 30% efficiency of the switch limited by the geometrical overlap between the cloud and the intersection volume of the two tunnels, and investigate the heating processes induced by the switch. We also showed other applications of crossed Bessel beams, such as a 3-D optical trap for atoms confined in the intersection volume of two hollow beams and a splitter of the atomic density. The second part of this dissertation is devoted to the spectroscopic measurements of the Rydberg blockade effect, a conditional suppression of Rydberg excitations depending on the state of a control atom. We assembled a narrow-linewidth, tunable, frequency stabilized laser system at 480 nm to excite laser-cooled rubidium atoms to Rydberg states with a high principal quantum number n ˜ 50 through a two-photon transition. We applied the laser system to observe the Autler-Townes splitting of the intermediate 5p3/2 state and used the broadening of the resonance features to investigate the enhancement of Rydberg-Rydberg interactions in the presence of an external electric field.

  9. On the dynamics of high Rydberg states of large molecules

    NASA Astrophysics Data System (ADS)

    Jortner, Joshua; Bixon, M.

    1995-04-01

    In this paper we explore the level structure, the optical excitation modes and the dynamics of a mixed Stark manifold of very high Rydberg states (with principal quantum numbers n=80-250) of large molecules, e.g., 1,4 diaza bicyclo [2,2,2] octane (DABCO) and bis (benzene) chromium (BBC) [U. Even, R. D. Levine, and R. Bersohn, J. Phys. Chem. 98, 3472 (1994)] and of autoionizing Rydbergs of atoms [F. Merkt, J. Chem. Phys. 100, 2623 (1994)], interrogated by time-resolved zero-electron kinetic energy (ZEKE) spectroscopy. We pursue the formal analogy between the level structure, accessibility and decay of very high Rydbergs in an external weak (F≂0.1-1 V cm-1) electric field and intramolecular (interstate and intrastate) relaxation in a bound molecular level structure. The onset n=nM of the strong mixing (in an external field F and in the field exerted by static ions) of a doorway state, which is characterized by a low azimuthal quantum number l, a finite quantum defect δ, and a total nonradiative width Γs≂Γ0/n3, with the inactive high l manifold is specified by nM≂80.6δ1/5(F/V cm-1)-1/5. At n≥nM the level structure and dynamics are characterized by the product γρ, where ρ is the density of states and γ=ΓsD(n) is the average decay width of the eigenstates, with the dilution factor D(n)≊n-2 for (lml) mixing and D(n)≂n-1 for (l) mixing, whereupon γρ=(Γ0/4δR)(nM/n)5, being independent of D(n). The sparse level structure is realized for γρ≪1, while the dense level structure prevails for γρ≳1, resulting in two limiting situations; (a) a dense limit for n≥nM and a sparse limit for n≫nM, and (b) a sparse limit for all n≥nM. The experimental information currently available on the decay dynamics of molecular (DABCO and BBC) and atomic (Ar) Rydbergs for n≥nM corresponds to case (b). The time-resolved dynamics was characterized in terms of the excited state total population probability P(t) and the population probability I(t) of the doorway

  10. Experimental investigations of dipole–dipole interactions between a few Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Browaeys, Antoine; Barredo, Daniel; Lahaye, Thierry

    2016-08-01

    This review summarizes experimental works performed over the last decade by several groups on the manipulation of a few individual interacting Rydberg atoms. These studies establish arrays of single Rydberg atoms as a promising platform for quantum-state engineering, with potential applications to quantum metrology, quantum simulation and quantum information.

  11. Measurement of the Spatial Distribution of Ultracold Cesium Rydberg Atoms by Time-of-Flight Spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Jingkui; Zhang, Linjie; Zhang, Hao; Zhao, Jianming; Jia, Suotang

    2015-09-01

    We prepare nS (n = 49) cesium Rydberg atoms by two-photon excitation in a standard magnetooptical trap to obtain the spatial distribution of the Rydberg atoms by measuring the time-of-flight (TOF) spectra in the case of a low Rydberg density. We analyze the time evolution of the ultracold nS Rydberg atoms distribution by changing the delay time of the pulsed ionization field, defined as the duration from the moment of switching off the excitation lasers to the time of switching on the ionization field. TOF spectra of Rydberg atoms are observed as a function of the delay time and initial Rydberg atomic density. The corresponding full widths at half maximum (FWHMs) are obtained by fitting the spectra with a Gaussian profile. The FWHM decreases with increasing delay time at a relatively high Rydberg atom density (>5 × 107/cm3) because of the decreasing Coulomb interaction between released charges during their flight to the detector. The temperature of the cold atoms is deduced from the dependence of the TOF spectra on the delay time under the condition of low Rydberg atom density.

  12. Spatially resolved excitation of Rydberg atoms and surface effects on an atom chip

    SciTech Connect

    Tauschinsky, Atreju; Thijssen, Rutger M. T.; Whitlock, S.; Linden van den Heuvell, H. B. van; Spreeuw, R. J. C.

    2010-06-15

    We demonstrate spatially resolved, coherent excitation of Rydberg atoms on an atom chip. Electromagnetically induced transparency (EIT) is used to investigate the properties of the Rydberg atoms near the gold-coated chip surface. We measure distance-dependent shifts ({approx}10 MHz) of the Rydberg energy levels caused by a spatially inhomogeneous electric field. The measured field strength and distance dependence is in agreement with a simple model for the electric field produced by a localized patch of Rb adsorbates deposited on the chip surface during experiments. The EIT resonances remain narrow (<4 MHz) and the observed widths are independent of atom-surface distance down to {approx} 20 {mu}m, indicating relatively long lifetime of the Rydberg states. Our results open the way to studies of dipolar physics, collective excitations, quantum metrology, and quantum information processing involving interacting Rydberg excited atoms on atom chips.

  13. Resonance-enhanced collective effect in a triangle arrangement of Rydberg atoms with anisotropic interactions

    NASA Astrophysics Data System (ADS)

    Qian, Jing

    2016-08-01

    We investigate the collective excitation effect in a scheme where three identical Rydberg atoms are arranged in an equilateral triangular lattice. By using a static electric field polarizing the atomic dipoles, the dipole-dipole interactions between two Rydberg atoms are essentially anisotropic and can even disappear in the several special resonance cases. For that fact, we observe collectively enhanced excitation probability of single Rydberg atom in resonant areas in the case of strong blockade, and that of double or triple Rydberg atoms in the case of partial blockade. To give more evidences for this collective excitation enhancement, we study the two-body quantum correlation between three Rydberg atoms, as well as the dependence of the blockade radius on the length of triangle sides, which present a good agreement with the excitation properties.

  14. Stretching and bending dynamics in triatomic ultralong-range Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Fey, Christian; Kurz, Markus; Schmelcher, Peter

    2016-07-01

    We investigate polyatomic ultralong-range Rydberg molecules consisting of three ground-state atoms bound to a Rydberg atom via s - and p -wave interactions. By employing the finite basis set representation of the unperturbed Rydberg electron Green's function we reduce the computational effort to solve the electronic problem substantially. This method is subsequently applied to determine the potential energy surfaces of triatomic systems in electronic s - and p -Rydberg states. Their molecular geometry and resulting vibrational structure are analyzed within an adiabatic approach that separates the vibrational bending and stretching dynamics. This procedure yields information on the radial and angular arrangement of the nuclei and indicates in particular that kinetic couplings between bending and stretching modes induce a linear structure in triatomic l =0 ultralong-range Rydberg molecules.

  15. Phase-Imprinting of Bose-Einstein Condensates with Rydberg Impurities

    NASA Astrophysics Data System (ADS)

    Mukherjee, Rick; Ates, Cenap; Li, Weibin; Wüster, Sebastian

    2015-07-01

    We show how the phase profile of Bose-Einstein condensates can be engineered through its interaction with localized Rydberg excitations. The interaction is made controllable and long range by off-resonantly coupling the condensate to another Rydberg state with laser light. Our technique allows the mapping of entanglement generated in systems of few strongly interacting Rydberg atoms onto much larger atom clouds in hybrid setups. As an example we discuss the creation of a spatial mesoscopic superposition state from a bright soliton. Additionally, the phase imprinted onto the condensate using the Rydberg excitations is a diagnostic tool for the latter. For example, a condensate time-of-flight image would permit reconstructing the pattern of an embedded Rydberg crystal.

  16. Phase-Imprinting of Bose-Einstein Condensates with Rydberg Impurities.

    PubMed

    Mukherjee, Rick; Ates, Cenap; Li, Weibin; Wüster, Sebastian

    2015-07-24

    We show how the phase profile of Bose-Einstein condensates can be engineered through its interaction with localized Rydberg excitations. The interaction is made controllable and long range by off-resonantly coupling the condensate to another Rydberg state with laser light. Our technique allows the mapping of entanglement generated in systems of few strongly interacting Rydberg atoms onto much larger atom clouds in hybrid setups. As an example we discuss the creation of a spatial mesoscopic superposition state from a bright soliton. Additionally, the phase imprinted onto the condensate using the Rydberg excitations is a diagnostic tool for the latter. For example, a condensate time-of-flight image would permit reconstructing the pattern of an embedded Rydberg crystal. PMID:26252669

  17. Toluene Valence and Rydberg Excitations as Studied by ab initio Calculations and Vacuum Ultraviolet (VUV) Synchrotron Radiation.

    PubMed

    Serralheiro, C; Duflot, D; da Silva, F Ferreira; Hoffmann, S V; Jones, N C; Mason, N J; Mendes, B; Limão-Vieira, P

    2015-08-27

    The electronic spectroscopy of isolated toluene in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 4.0-10.8 eV energy range, with absolute cross-section measurements derived. We present the first set of ab initio calculations (vertical energies and oscillator strengths), which we use in the assignment of valence and Rydberg transitions of the toluene molecule. The spectrum reveals several new features not previously reported in the literature, with particular relevance to 7.989 and 8.958 eV, which are here tentatively assigned to the π*(17a') ← σ(15a') and 1π*(10a″) ← 1π(14a') transitions, respectively. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of toluene in the upper stratosphere (20-50 km). PMID:26244250

  18. Vacuum ultraviolet studies of electron impact of helium: Excitation of He n P Rydberg series and ionization-excitation of He nl Rydberg series

    SciTech Connect

    Shemansky, D.E.; Hall, D.T.; Ajello, J.M.; Franklin, B.

    1985-09-15

    Laboratory measurements of the electron excitation cross sections of emission in the He Rydberg series (1sS S-1snp P) for n = 2,3,4 have been obtained. The cross sections were estimated by two methods: (1) analysis of calibrated laboratory spectra placed on an absolute scale using the H Ly dissociative excitation standard and (2) analysis of relative cross section data using a modified Born approximation. A new method has been developed for the application of the Bethe-Born approximation using experimental relative excitation functions that does not require extrapolation in a Fano plot in the determination of the absolute cross section. The two methods agree to within 3% for the 58.4 nm line when allowance is made for cascade transitions. We find the direct excitation cross sections at 200 eV for the n = 2,3,4 members of the published electron impact experimental measurements of the two electron process of ionization-excitation impact are generally in agreement, especially on the energy dependence of excitation functions, but show significant differences with theoretical calculations.

  19. Sub-Doppler two-photon-excitation Rydberg spectroscopy of atomic xenon: mass-selective studies of isotopic and hyperfine structure

    NASA Astrophysics Data System (ADS)

    Kono, Mitsuhiko; He, Yabai; Baldwin, Kenneth G. H.; Orr, Brian J.

    2016-03-01

    Mass-selective sub-Doppler two-photon excitation (TPE) spectroscopy is employed to resolve isotopic contributions for transitions to high-energy Rydberg levels of xenon in an atomic beam, using narrowband pulses of coherent ultraviolet light at 205-213 nm generated by nonlinear-optical conversion processes. Previous research (Kono et al 2013 J. Phys. B: At. Mol. Opt. Phys. 46 35401), has determined isotope energy shifts and hyperfine structure for 33 high-energy Rydberg levels of gas-phase xenon and accessed Rydberg levels at TPE energies in the range of 94 100-97 300 cm-1 with unprecedented spectroscopic resolution. The new isotopic-mass-resolved results were obtained by adding a pulsed free-jet atomic-beam source and a mass-selective time-of-flight detector to the apparatus in order to discern individual xenon isotopes and extract previously unresolved spectroscopic information. Resulting isotope energy shifts and hyperfine-coupling parameters are examined with regard to trends in principal quantum number n and in atomic angular-momentum quantum numbers, together with empirical and theoretical precedents for such trends.

  20. Rotationally Resolved Vacuum Ultraviolet Resonance-Enhanced Multiphoton Ionization (VUV REMPI) of Acetylene via the G̃ Rydberg State.

    PubMed

    Schmidt-May, Alice F; Grütter, Monika; Neugebohren, Jannis; Kitsopoulos, T N; Wodtke, Alec M; Harding, Dan J

    2016-07-14

    We present a 1 + 1' resonance-enhanced multiphoton ionization (REMPI) scheme for acetylene via the linear G̃ 4sσ (1)Πu Rydberg state, offering partial rotational resolution and the possibility to detect excitation in both the cis- and trans-bending modes. The resonant transition to the G̃ state is driven by a vacuum ultraviolet (VUV) photon, generated by resonant four-wave mixing (FWM) in krypton. Ionization from the short-lived G̃ state then occurs quickly, driven by the high intensity of the residual light from the FWM process. We have observed nine bands in the region between 79 200 cm(-1) and 80 500 cm(-1) in C2H2 and C2D2. We compare our results with published spectra in this region and suggest alternative assignments for some of the Renner-Teller split bands. Similar REMPI schemes should be applicable to other small molecules with picosecond lifetime Rydberg states. PMID:27073931

  1. Transfer of a weakly bound electron in collisions of Rydberg atoms with neutral particles. II. Ion-pair formation and resonant quenching of the Rb(nl) and Ne(nl) States by Ca, Sr, and Ba atoms

    SciTech Connect

    Narits, A. A.; Mironchuk, E. S.; Lebedev, V. S.

    2013-10-15

    Electron-transfer processes are studied in thermal collisions of Rydberg atoms with alkaline-earth Ca(4s{sup 2}), Sr(5s{sup 2}), and Ba(6s{sup 2}) atoms capable of forming negative ions with a weakly bound outermost p-electron. We consider the ion-pair formation and resonant quenching of highly excited atomic states caused by transitions between Rydberg covalent and ionic terms of a quasi-molecule produced in collisions of particles. The contributions of these reaction channels to the total depopulation cross section of Rydberg states of Rb(nl) and Ne(nl) atoms as functions of the principal quantum number n are compared for selectively excited nl-levels with l Much-Less-Than n and for states with large orbital quantum numbers l = n - 1, n - 2. It is shown that the contribution from resonant quenching dominates at small values of n, and the ion-pair formation process begins to dominate with increasing n. The values and positions of the maxima of cross sections for both processes strongly depend on the electron affinity of an alkaline-earth atom and on the orbital angular momentum l of a highly excited atom. It is shown that in the case of Rydberg atoms in states with large l {approx} n - 1, the rate constants of ion-pair formation and collisional quenching are considerably lower than those for nl-levels with l Much-Less-Than n.

  2. Seeded excitation avalanches in off-resonantly driven Rydberg gases

    NASA Astrophysics Data System (ADS)

    Simonelli, C.; Valado, M. M.; Masella, G.; Asteria, L.; Arimondo, E.; Ciampini, D.; Morsch, O.

    2016-08-01

    We report an experimental investigation of the facilitated excitation dynamics in off-resonantly driven Rydberg gases by separating the initial off-resonant excitation phase from the facilitation phase, in which successive facilitation events lead to excitation avalanches. We achieve this by creating a controlled number of initial seed excitations. Greater insight into the avalanche mechanism is obtained from an analysis of the full counting distributions. We also present simple mathematical models and numerical simulations of the excitation avalanches that agree well with our experimental results.

  3. Control of multiple excited Rydberg states around segmented carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Schmelcher, Peter; Sadeghpour, Hossein; Knoerzer, Johannes; Fey, Christian

    2016-05-01

    Electronic image Rydberg states around segmented carbon nanotubes can be confined and shaped along the nanotube axis by engineering the image potential. We show how several such image states can be prepared simultaneously along the same nanotube. The inter-electronic distance can be controlled a priori by engineering tubes of specific geometries. High sensitivity to external electric and magnetic fields can be exploited to manipulate these states and their mutual long-range interactions. These building blocks provide access to a new kind of tailored long-range interacting quantum systems.

  4. Optimal control for Rydberg quantum technology building blocks

    NASA Astrophysics Data System (ADS)

    Müller, Matthias M.; Pichler, Thomas; Montangero, Simone; Calarco, Tommaso

    2016-04-01

    We consider a platform for quantum technology based on Rydberg atoms in optical lattices where each atom encodes one qubit of information and external lasers can manipulate their state. We demonstrate how optimal control theory enables the functioning of two specific building blocks on this platform: We engineer an optimal protocol to perform a two-qubit phase gate and to transfer the information within the lattice among specific sites. These two elementary operations allow to design very general operations like storage of atoms and entanglement purification as, for example, needed for quantum repeaters.

  5. The kicked Rydberg atom: Regular and stochastic motion

    SciTech Connect

    Burgdoerfer, J.

    1988-01-01

    We have investigated the dynamics of a three-dimensional classical Rydberg atom driven by a sequence of pulses. Both the deterministic system with periodic pulses and the closely related ''noisy'' system with random pulses have been studied in parallel. The Lyapunov exponent is calculated as a function of pulse height and the angular momentum of the initial state. We find differences between noisy and deterministic perturbations to be most pronounced for small pulse heights. Low angular momentum orbits show enhanced diffusion in agreement with recent experimental data for ion-solid interaction. 22 refs., 6 figs.

  6. High-Rydberg Xenon Submillimeter-Wave Detector

    NASA Technical Reports Server (NTRS)

    Chutjian, Ara

    1987-01-01

    Proposed detector for infrared and submillimeter-wavelength radiation uses excited xenon atoms as Rydberg sensors instead of customary beams of sodium, potassium, or cesium. Chemically inert xenon easily stored in pressurized containers, whereas beams of dangerously reactive alkali metals must be generated in cumbersome, unreliable ovens. Xenon-based detector potential for infrared astronomy and for Earth-orbiter detection of terrestrial radiation sources. Xenon atoms excited to high energy states in two stages. Doubly excited atoms sensitive to photons in submillimeter wavelength range, further excited by these photons, then ionized and counted.

  7. Hydrogenic Rydberg States of Molecular van der Waals Complexes: Resolved Rydberg Spectroscopy of DABCO-N2

    NASA Astrophysics Data System (ADS)

    Cockett, Martin C.; Watkins, Mark J.

    2004-01-01

    The complementary threshold ionization techniques of MATI and ZEKE spectroscopy have been used to reveal well-resolved, long-lived (>10 μs) hydrogenic Rydberg series (50≤n≤98) in a van der Waals complex formed between a polyatomic molecule and a diatomic molecule for the first time. The series are observed within 50 cm-1 of the adiabatic ionization threshold as well as two core-excited thresholds corresponding to excitation of up to two quanta in the van der Waals vibra­tional mode.

  8. Divalent Rydberg atoms in optical lattices: Intensity landscape and magic trapping

    NASA Astrophysics Data System (ADS)

    Topcu, Turker; Derevianko, Andrei

    2014-02-01

    We develop a theoretical understanding of the trapping of divalent Rydberg atoms in optical lattices. Because the size of the Rydberg electron cloud can be comparable to the scale of spatial variations of laser intensity, we pay special attention to averaging optical fields over the atomic wave functions. The optical potential is proportional to the ac Stark polarizability. We find that in the independent-particle approximation for the valence electrons, this polarizability breaks into two contributions: the singly ionized core polarizability and the contribution from the Rydberg electron. Unlike the usually employed free-electron polarizability, the Rydberg contribution depends both on the laser intensity profile and on the rotational symmetry of the total electronic wave function. We focus on the J =0 Rydberg states of Sr and evaluate the dynamic polarizabilities of the 5sns(1S0) and 5snp(3P0) Rydberg states. We specifically chose the Sr atom for its optical-lattice clock applications. We find that there are several magic wavelengths in the infrared region of the spectrum at which the differential Stark shift between the clock states [5s2(1S0) and 5s5p(3P0)] and the J =0 Rydberg states [5sns(1S0) and 5snp(3P0)] vanishes. We tabulate these wavelengths as a function of the principal quantum number n of the Rydberg electron. We find that because the contribution to the total polarizability from the Rydberg electron vanishes at short wavelengths, magic wavelengths below ˜1000 nm are "universal" as they do not depend on the principal quantum number n.

  9. Far infrared stimulated emission from the ns and nf Rydberg states of NO

    SciTech Connect

    Furukawa, Hiroki; Araki, Mitsunori; Umeki, Hiroya; Tsukiyama, Koichi

    2013-06-28

    We report directional far-infrared emission from the {upsilon}= 0 vibrational levels of the 9s{sigma}, 10s{sigma}, 11s{sigma}, 9f, and 10f Rydberg states of NO in the gas phase. The emission around 28 and 19 {mu}m from the 9f state was identified as the downward 9f{yields} 8g and subsequent 8g{yields} 7f cascade transitions, respectively. The emission around 38 and 40 {mu}m from the 10f state was identified as the 10f{yields} 9g and 10f{yields} 9d{sigma}{pi} transition, respectively. Following the excitation of the 9s{sigma}, 10s{sigma}, and 11s{sigma} states, the emission around 40, 60, and 83 {mu}m was assigned as the 9s{sigma}{yields} 8p{sigma}, 10s{sigma}{yields} 9p{sigma}, and 11s{sigma}{yields} 10p{sigma} transitions, respectively. In addition to these emission systems originated from the laser-prepared levels, we found the emission bands from the 8f, 9f, and 10f states which are located energetically above the 9s{sigma}, 10s{sigma}, and 11s{sigma} states, respectively. This observation suggests that the upward 8f Leftwards-Arrow 9s{sigma}, 9f Leftwards-Arrow 10s{sigma}, and 10f Leftwards-Arrow 11s{sigma} optical excitation occurs. Since the energy differences between nf and (n+ 1)s{sigma} states correspond to the wavelength longer than 100 {mu}m, the absorption of blackbody radiation is supposed to be essential for these upward transitions.

  10. Robust quantum logic in neutral atoms via adiabatic Rydberg dressing

    SciTech Connect

    Keating, Tyler; Cook, Robert L.; Hankin, Aaron M.; Jau, Yuan -Yu; Biedermann, Grant W.; Deutsch, Ivan H.

    2015-01-28

    We study a scheme for implementing a controlled-Z (CZ) gate between two neutral-atom qubits based on the Rydberg blockade mechanism in a manner that is robust to errors caused by atomic motion. By employing adiabatic dressing of the ground electronic state, we can protect the gate from decoherence due to random phase errors that typically arise because of atomic thermal motion. In addition, the adiabatic protocol allows for a Doppler-free configuration that involves counterpropagating lasers in a σ+- orthogonal polarization geometry that further reduces motional errors due to Doppler shifts. The residual motional error is dominated by dipole-dipole forces acting on doubly-excited Rydberg atoms when the blockade is imperfect. As a result, for reasonable parameters, with qubits encoded into the clock states of 133Cs, we predict that our protocol could produce a CZ gate in < 10 μs with error probability on the order of 10-3.

  11. Controlled long-range interactions between Rydberg atoms and ions

    NASA Astrophysics Data System (ADS)

    Secker, T.; Gerritsma, R.; Glaetzle, A. W.; Negretti, A.

    2016-07-01

    We theoretically investigate trapped ions interacting with atoms that are coupled to Rydberg states. The strong polarizabilities of the Rydberg levels increase the interaction strength between atoms and ions by many orders of magnitude, as compared to the case of ground-state atoms, and may be mediated over micrometers. We calculate that such interactions can be used to generate entanglement between an atom and the motion or internal state of an ion. Furthermore, the ion could be used as a bus for mediating spin-spin interactions between atomic spins in analogy to much employed techniques in ion-trap quantum simulation. The proposed scheme comes with attractive features as it maps the benefits of the trapped-ion quantum system onto the atomic one without obviously impeding its intrinsic scalability. No ground-state cooling of the ion or atom is required and the setup allows for full dynamical control. Moreover, the scheme is to a large extent immune to the micromotion of the ion. Our findings are of interest for developing hybrid quantum information platforms and for implementing quantum simulations of solid-state physics.

  12. Robust quantum logic in neutral atoms via adiabatic Rydberg dressing

    DOE PAGESBeta

    Keating, Tyler; Cook, Robert L.; Hankin, Aaron M.; Jau, Yuan -Yu; Biedermann, Grant W.; Deutsch, Ivan H.

    2015-01-28

    We study a scheme for implementing a controlled-Z (CZ) gate between two neutral-atom qubits based on the Rydberg blockade mechanism in a manner that is robust to errors caused by atomic motion. By employing adiabatic dressing of the ground electronic state, we can protect the gate from decoherence due to random phase errors that typically arise because of atomic thermal motion. In addition, the adiabatic protocol allows for a Doppler-free configuration that involves counterpropagating lasers in a σ+/σ- orthogonal polarization geometry that further reduces motional errors due to Doppler shifts. The residual motional error is dominated by dipole-dipole forces actingmore » on doubly-excited Rydberg atoms when the blockade is imperfect. As a result, for reasonable parameters, with qubits encoded into the clock states of 133Cs, we predict that our protocol could produce a CZ gate in < 10 μs with error probability on the order of 10-3.« less

  13. Multichannel quantum defect theory of strontium bound Rydberg states

    NASA Astrophysics Data System (ADS)

    Vaillant, C. L.; Jones, M. P. A.; Potvliege, R. M.

    2014-08-01

    Using the reactance matrix approach, we systematically develop new multichannel quantum defect theory (MQDT) models for the singlet and triplet S, P, D and F states of strontium below the first ionization limit, based on improved energy level measurements. The new models reveal additional insights into the character of doubly excited perturber states, and the improved energy level measurements for certain series allow fine structure to be resolved for those series’ perturbers. Comparison between the predictions of the new models and those of previous empirical and ab initio studies reveals good agreement with most series; however, some discrepancies are highlighted. Using the MQDT wave functions derived from our models we calculate other observables such as Landé {{g}J}-factors and radiative lifetimes. The analysis reveals the impact of perturbers on the Rydberg state properties of divalent atoms, highlighting the importance of including two-electron effects in the calculations of these properties. The work enables future investigations of properties such as Stark maps and long-range interactions of Rydberg states of strontium.

  14. Dipole-dipole interaction between rubidium Rydberg atoms

    SciTech Connect

    Altiere, Emily; Fahey, Donald P.; Noel, Michael W.; Smith, Rachel J.; Carroll, Thomas J.

    2011-11-15

    Ultracold Rydberg atoms in a static electric field can exchange energy via the dipole-dipole interaction. The Stark effect shifts the energy levels of the atoms which tunes the energy exchange into resonance at specific values of the electric field (Foerster resonances). We excite rubidium atoms to Rydberg states by focusing either a 480 nm beam from a tunable dye laser or a pair of diode lasers into a magneto-optical trap. The trap lies at the center of a configuration of electrodes. We scan the electric field by controlling the voltage on the electrodes while measuring the fraction of atoms that interact. Dipole-dipole interaction spectra are presented for initially excited rubidium nd states for n=31 to 46 and for four different pairs of initially excited rubidium ns states. We also present the dipole-dipole interaction spectra for individual rubidium 32d (j, m{sub j}) fine structure levels that have been selectively excited. The data are compared to calculated spectra.

  15. Full counting statistics of laser excited Rydberg aggregates in a one-dimensional geometry.

    PubMed

    Schempp, H; Günter, G; Robert-de-Saint-Vincent, M; Hofmann, C S; Breyel, D; Komnik, A; Schönleber, D W; Gärttner, M; Evers, J; Whitlock, S; Weidemüller, M

    2014-01-10

    We experimentally study the full counting statistics of few-body Rydberg aggregates excited from a quasi-one-dimensional atomic gas. We measure asymmetric excitation spectra and increased second and third order statistical moments of the Rydberg number distribution, from which we determine the average aggregate size. Estimating rates for different excitation processes we conclude that the aggregates grow sequentially around an initial grain. Direct comparison with numerical simulations confirms this conclusion and reveals the presence of liquidlike spatial correlations. Our findings demonstrate the importance of dephasing in strongly correlated Rydberg gases and introduce a way to study spatial correlations in interacting many-body quantum systems without imaging. PMID:24483893

  16. Microwaves Probe Dipole Blockade and van der Waals Forces in a Cold Rydberg Gas.

    PubMed

    Teixeira, R Celistrino; Hermann-Avigliano, C; Nguyen, T L; Cantat-Moltrecht, T; Raimond, J M; Haroche, S; Gleyzes, S; Brune, M

    2015-07-01

    We show that microwave spectroscopy of a dense Rydberg gas trapped on a superconducting atom chip in the dipole blockade regime reveals directly the dipole-dipole many-body interaction energy spectrum. We use this method to investigate the expansion of the Rydberg cloud under the effect of repulsive van der Waals forces and the breakdown of the frozen gas approximation. This study opens a promising route for quantum simulation of many-body systems and quantum information transport in chains of strongly interacting Rydberg atoms. PMID:26182093

  17. The dynamics of high autoionizing Rydberg states of Ar

    NASA Astrophysics Data System (ADS)

    Bixon, M.; Jortner, Joshua

    1995-09-01

    In this paper we present a theoretical study of the autoionization dynamics of high 2P1/2np'[3/2]1 Rydbergs (with the principal quantum numbers n=100-280) of Ar in weak homogeneous electric fields (F=0.01-1.0 V/cm), which were experimentally interrogated by time-resolved zero-electron kinetic energy (ZEKE) spectroscopy [M. Mühlpfordt and U. Even, J. Chem. Phys. 103, 4427 (1995)], and which exhibit a marked dilution (i.e., ˜2 orders of magnitude lengthening) of the lifetimes relative to those inferred on the basis of the n3 scaling law for the spectral linewidths of the np' (n=12-24) Rydbergs. The multichannel effective Hamiltonian (Heff) with several doorway state(s) (for excitation and decay) and pure escape states (for decay) was advanced and utilized to treat the dynamics of the mixed Stark manifold of the ZEKE Rydbergs. Heff of dimension 2n-1 is then constructed for a n Rydberg manifold using independent experimental information on the (l dependent) quantum defects δ(l) and the (l, K, J dependent) decay widths, which are of the form Γ0(lKJ)/(n-δ(l))3, with Γ0(lKJ) being the decay widths constants. Here, l, K, and J are the azimuthal, the electronic and the total electronic angular momentum quantum numbers, respectively. Two coupling ranges are distinguished according to the strength of the reduced electric field F¯(n,p')=(F/V cm-1)n5/ 3.4×109[δ(p')(mod1)]. Range (A); The onset of the effective coupling of the doorway and escape states, i.e., 0.7≤F¯(n,p')≤2. Range (B); The strong mixing domain F¯(n,p')≥3. The lifetimes in range (B) can be well represented by a nearly democratic mixing of all the doorway and escape states (lKJ), with the average value <τ(n)>≂<τSM(n)>= 2n4ℏ/[J(lJK)Γ0(lJK)]. In range (B) <τ(n)> increases with increasing n and is only weakly F dependent. Range (A) is characterized by a hierarchy of two time scales for the decay, with a short decay component, which manifests the residue of the doorway state, and a

  18. Sub-Poissonian statistics of Rydberg-interacting dark-state polaritons.

    PubMed

    Hofmann, C S; Günter, G; Schempp, H; Robert-de-Saint-Vincent, M; Gärttner, M; Evers, J; Whitlock, S; Weidemüller, M

    2013-05-17

    We observe individual dark-state polaritons as they propagate through an ultracold atomic gas involving Rydberg states coupled via an electromagnetically induced transparency resonance. Strong long-range interactions between Rydberg excitations give rise to a blockade between polaritons, resulting in large optical nonlinearities and modified polariton number statistics. By combining optical imaging and high-fidelity detection of the Rydberg polaritons we investigate both aspects of this coupled atom-light system. We map out the full nonlinear optical response as a function of atomic density and follow the temporal evolution of polaritons through the atomic cloud. In the blockade regime, the statistical fluctuations of the polariton number drop well below the quantum noise limit. The low level of fluctuations indicates that photon correlations modified by the strong interactions have a significant backaction on the Rydberg atom statistics. PMID:25167407

  19. Quantum Magnetism and Topological Ordering via Rydberg Dressing near Förster Resonances.

    PubMed

    van Bijnen, R M W; Pohl, T

    2015-06-19

    We devise a cold-atom approach to realizing a broad range of bilinear quantum magnets. Our scheme is based on off-resonant single-photon excitation of Rydberg P states (Rydberg dressing), whose strong interactions are shown to yield controllable XYZ interactions between effective spins, represented by different atomic ground states. The distinctive features of Förster-resonant Rydberg atom interactions are exploited to enhance the effectiveness of Rydberg dressing and, thereby, yield large spin interactions that greatly exceed the corresponding decoherence rates. We illustrate the concept on a spin-1 chain implemented with cold rubidium atoms, and demonstrate that this permits the dynamical preparation of topological magnetic phases. Generally, the described approach provides a viable route to exploring quantum magnetism with dynamically tunable (an)isotropic interactions as well as variable space and spin dimensions in cold-atom experiments. PMID:26196973

  20. Resonant charge transfer of hydrogen Rydberg atoms incident at a metallic sphere

    NASA Astrophysics Data System (ADS)

    Gibbard, J. A.; Softley, T. P.

    2016-06-01

    A wavepacket propagation study is reported for the charge transfer of low principal quantum number (n = 2) hydrogen Rydberg atoms incident at an isolated metallic sphere. Such a sphere acts as a model for a nanoparticle. The three-dimensional confinement of the sphere yields discrete surface-localized ‘well-image’ states, the energies of which vary with sphere radius. When the Rydberg atom energy is degenerate with one of the quantized nanoparticle states, charge transfer is enhanced, whereas for off-resonant cases little to no charge transfer is observed. Greater variation in charge-transfer probability is seen between the resonant and off-resonant examples in this system than for any other Rydberg-surface system theoretically investigated thus far. The results presented here indicate that it may be possible to use Rydberg-surface ionization as a probe of the surface electronic structure of a nanoparticle, and nanostructures in general.

  1. Trap losses induced by near-resonant Rydberg dressing of cold atomic gases

    NASA Astrophysics Data System (ADS)

    Aman, J. A.; DeSalvo, B. J.; Dunning, F. B.; Killian, T. C.; Yoshida, S.; Burgdörfer, J.

    2016-04-01

    The near-resonant dressing of cold strontium gases and Bose-Einstein condensates contained in an optical dipole trap (ODT) with the 5 s 30 s S31 Rydberg state is investigated as a function of the effective two-photon Rabi frequency, detuning, and dressing time. The measurements demonstrate that a rapid decrease in the ground-state atom population in the ODT occurs even for weak dressing and when well detuned from resonance. This decrease is attributed to Rydberg atom excitation, which can lead to direct escape from the trap and to population of very long-lived 5 s 5 p 0, 2 3P metastable states. The effects of interactions between Rydberg atoms, including those populated by blackbody radiation, are analyzed. The work has important implications when considering the use of Rydberg dressing to control the interactions between dressed ground-state atoms.

  2. Direct Measurement of the van der Waals Interaction between Two Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Béguin, L.; Vernier, A.; Chicireanu, R.; Lahaye, T.; Browaeys, A.

    2013-06-01

    We report the direct measurement of the van der Waals interaction between two isolated, single Rydberg atoms separated by a controlled distance of a few micrometers. Working in a regime where the single-atom Rabi frequency for excitation to the Rydberg state is comparable to the interaction, we observe partial Rydberg blockade, whereby the time-dependent populations of the various two-atom states exhibit coherent oscillations with several frequencies. Quantitative comparison of the data with a simple model based on the optical Bloch equations allows us to extract the van der Waals energy, and observe its characteristic C6/R6 dependence. The measured C6 coefficients agree well with ab initio calculations, and we observe their dramatic increase with the principal quantum number n of the Rydberg state.

  3. A model for charge transfer in ultracold Rydberg ground-state atomic collisions

    NASA Astrophysics Data System (ADS)

    Markson, Samuel; Sadeghpour, H. R.

    2016-06-01

    In excited molecules, the interaction between the covalent Rydberg and ion-pair channels forms a unique class of excited states, in which the infinite manifold of vibrational levels are the equivalent of atomic Rydberg states with a heavy electron mass. Production of the ion-pair states usually requires excitation through one or several interacting Rydberg states; these interacting channels lead to loss of flux, diminishing the rate of ion-pair production. Here, we develop an analytical, asymptotic charge-transfer model for the interaction between ultracold Rydberg molecular states, and employ this method to demonstrate the utility of off-resonant field control over the ion-pair formation, with near unity efficiency.

  4. State-Mixing of nS Rydberg Atoms in an External Electric Field

    NASA Astrophysics Data System (ADS)

    Jiao, Yuechun; Wang, Limei; Zhang, Hao; Zhang, Linjie; Zhao, Jianming; Jia, Suotang

    2015-09-01

    State-mixing effect of ultracold nS cesium Rydberg atoms in an external electric field is investigated in a magneto-optical trap. Populated high-l Rydberg atoms due to the state-mixing through avoided crossings are measured with a state-selective field ionization technique. The measured transfer rates of high-l states increase with the electric field and get to the maximum at the field of about 3.0 V/cm for 49S1/2 Rydberg state, and show decrease behavior when the electric field increases further. The decrease behavior of the transfer rate is explained with the slower m-mixing effect caused by decreasing dipole-dipole interactions between high-l Rydberg atoms. During the m-mixing process the ultracold plasma is formed by the Penning ionization.

  5. Quantum controlled-phase-flip gate between a flying optical photon and a Rydberg atomic ensemble

    PubMed Central

    Hao, Y. M.; Lin, G. W.; Xia, Keyu; Lin, X. M.; Niu, Y. P.; Gong, S. Q.

    2015-01-01

    Quantum controlled-phase-flip (CPF) gate between a flying photon qubit and a stationary atomic qubit could allow the linking of distant computational nodes in a quantum network. Here we present a scheme to realize quantum CPF gate between a flying optical photon and an atomic ensemble based on cavity input-output process and Rydberg blockade. When a flying single-photon pulse is reflected off the cavity containing a Rydberg atomic ensemble, the dark resonance and Rydberg blockade induce a conditional phase shift for the photon pulse, thus we can achieve the CPF gate between the photon and the atomic ensemble. Assisted by Rydberg blockade interaction, our scheme works in the N-atoms strong-coupling regime and significantly relaxes the requirement of strong coupling of single atom to photon in the optical cavity. PMID:25966448

  6. Radio-frequency Electrometry Using Rydberg Atoms in Vapor Cells: Towards the Shot Noise Limit

    NASA Astrophysics Data System (ADS)

    Kumar, Santosh; Fan, Haoquan; Jahangiri, Akbar; Kuebler, Harald; Shaffer, James P.; 5. Physikalisches Institut, Universitat Stuttgart, Germany Collaboration

    2016-05-01

    Rydberg atoms are a promising candidate for radio frequency (RF) electric field sensing. Our method uses electromagnetically induced transparency with Rydberg atoms in vapor cells to read out the effect that the RF electric field has on the Rydberg atoms. The method has the potential for high sensitivity (pV cm-1 Hz- 1 / 2) and can be self-calibrated. Some of the main factors limiting the sensitivity of RF electric field sensing from reaching the shot noise limit are the residual Doppler effect and the sensitivity of the optical read-out using the probe laser. We present progress on overcoming the residual Doppler effect by using a new multi-photon scheme and reaching the shot noise detection limit using frequency modulated spectroscopy. Our experiments also show promise for studying quantum optical effects such as superradiance in vapor cells using Rydberg atoms. This work is supported by DARPA, ARO, and NRO.

  7. Properties of Th3+ from Optical Spectroscopy of High-L Rydberg states of Th2+

    NASA Astrophysics Data System (ADS)

    Keele, Julie; Woods, Shannon; Lundeen, Stephen; Fehrenbach, Charles

    2011-05-01

    The Fr-like Thorium ion, Th3+, has one valence electron outside a Rn-like closed shell, but its ground electronic state is 2F5/2 instead of 2S1/2 due to the high nuclear charge. The positions of the lowest seven levels of this ion have been established by optical spectroscopy, but no other properties have been measured previously. We measure the properties of the Th3+ ground state that control its long-range interactions, such as polarizabilities and permanent moments, by attaching a single electron in a non-penetrating Rydberg state and measuring the details of its binding energy using the Resonant Excitation Stark Ionization Spectroscopy (RESIS) technique. A typical transition is n = 29 to n ' = 72. The laser excitation partially resolves the complex fine structure pattern in the lower state caused by the long-range interactions, and this leads to measurements of the core ion properties controlling those interactions. Supported by the Chemical Sciences, Geosciences, and Biosciences Division of the Office of Basic Energy Science, U.S. Dept. of Energy.

  8. Adsorbate dynamics on a silica-coated gold surface measured by Rydberg Stark spectroscopy

    NASA Astrophysics Data System (ADS)

    Naber, J.; Machluf, S.; Torralbo-Campo, L.; Soudijn, M. L.; van Druten, N. J.; van Linden van den Heuvell, H. B.; Spreeuw, R. J. C.

    2016-05-01

    Trapping a Rydberg atom close to a surface is an important step towards the realisation of many proposals for quantum information processing or hybrid quantum systems. One of the challenges in these experiments is posed by the electric field emanating from contaminations on the surface. Here we report on measurements of an electric field created by 87Rb atoms adsorbed on a 25 nm thick layer of SiO2, covering a 90 nm layer of Au. The electric field is measured using a two-photon transition to the 23{D}5/2 and 25{S}1/2 states. The electric field value that we measure is higher than typical values measured above metal surfaces, but is consistent with a recent measurement above a SiO2 surface. In addition, we measure the temporal behaviour of the field and observe that we can reduce it in a single experimental cycle, using ultraviolet light or by mildly locally heating the surface with one of the excitation lasers, whereas the buildup of the field takes thousands of cycles. We explain these results by a change in the adatom distribution on the surface. These results indicate that, while the stray electric field can be reduced, achieving field-free conditions above a silica-coated gold chip remains challenging.

  9. Experimental progress towards a Rydberg atom-photon-superconductor quantum interface

    NASA Astrophysics Data System (ADS)

    Isaacs, J. A.; Pritchard, J. D.; Xia, T.; Beck, M. A.; McDermott, R.; Saffman, M.

    2015-05-01

    Hybrid quantum computation exploits the individual strengths of various quantum technologies, enabling realization of a scalable quantum device capable of both fast gates and long coherence times. Our method combines the long coherence times of neutral atoms with the fast gates of superconducting qubits. We discuss experimental progress towards single atom trapping close to a superconducting resonator, including optimization of the resonator to maximize the quality factor and coupling strength for preliminary experiments performed at 4 K. We use a new resonator design, incorporating 3D micro fabricated structures, that allows for strong electric field coupling to an atom trapped ~ 50 μ m above the resonator. Our scheme uses a novel two-photon Rydberg excitation via the 6S1 / 2 --> 5D5 / 2 quadrupole transition to enable direct excitation of nP3 / 2 states for strong electric-dipole coupling to the cavity. This significantly reduces the Doppler mismatch compared to previous two-photon excitation schemes to enable high fidelity operations. First spectroscopy and Rabi oscillation results will be shown. Work supported by NSF award PHY-1212448.

  10. Singlet-triplet electron scattering admixture due to fine- and hyper-fine interactions in Cs Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Markson, Samuel; Rittenhouse, Seth; Sadeghpour, Hossein

    2016-05-01

    We will present the admixture of singlet electron scattering into the more dominant triplet scattering in the formation of ultracold Cs Rydberg molecules excited into non-zero electronic angular momentum states. This admixture comes about due to both spin-orbit (SO) coupling in the Rydberg atom as well as the hyperfine (HF) coupling in the ground state atom. In Cs, the Rydberg SO and ground HF interactions are on par. The interaction between the Rydberg electron and the ground state atom includes both s-wave and p-wave scattering components which can cause additional mixing of electronic Rydberg states in the bound molecules. We intend to apply the formalism to Rydberg excitation in Cs in p and d states and will give a progress report at the meeting.

  11. Self-interaction corrected density functional calculations of molecular Rydberg states

    SciTech Connect

    Gudmundsdóttir, Hildur; Zhang, Yao; Weber, Peter M.; Jónsson, Hannes

    2013-11-21

    A method is presented for calculating the wave function and energy of Rydberg excited states of molecules. A good estimate of the Rydberg state orbital is obtained using ground state density functional theory including Perdew-Zunger self-interaction correction and an optimized effective potential. The total energy of the excited molecule is obtained using the Delta Self-Consistent Field method where an electron is removed from the highest occupied orbital and placed in the Rydberg orbital. Results are presented for the first few Rydberg states of NH{sub 3}, H{sub 2}O, H{sub 2}CO, C{sub 2}H{sub 4}, and N(CH{sub 3}){sub 3}. The mean absolute error in the energy of the 33 molecular Rydberg states presented here is 0.18 eV. The orbitals are represented on a real space grid, avoiding the dependence on diffuse atomic basis sets. As in standard density functional theory calculations, the computational effort scales as NM{sup 2} where N is the number of orbitals and M is the number of grid points included in the calculation. Due to the slow scaling of the computational effort with system size and the high level of parallelism in the real space grid approach, the method presented here makes it possible to estimate Rydberg electron binding energy in large molecules.

  12. Designing Frustrated Quantum Magnets with Laser-Dressed Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Glaetzle, Alexander W.; Dalmonte, Marcello; Nath, Rejish; Gross, Christian; Bloch, Immanuel; Zoller, Peter

    2015-05-01

    We show how a broad class of lattice spin-1 /2 models with angular- and distance-dependent couplings can be realized with cold alkali atoms stored in optical or magnetic trap arrays. The effective spin-1 /2 is represented by a pair of atomic ground states, and spin-spin interactions are obtained by admixing van der Waals interactions between fine-structure split Rydberg states with laser light. The strengths of the diagonal spin interactions as well as the "flip-flop," and "flip-flip" and "flop-flop" interactions can be tuned by exploiting quantum interference, thus realizing different spin symmetries. The resulting energy scales of interactions compare well with typical temperatures and decoherence time scales, making the exploration of exotic forms of quantum magnetism, including emergent gauge theories and compass models, accessible within state-of-the-art experiments.

  13. Designing frustrated quantum magnets with laser-dressed Rydberg atoms.

    PubMed

    Glaetzle, Alexander W; Dalmonte, Marcello; Nath, Rejish; Gross, Christian; Bloch, Immanuel; Zoller, Peter

    2015-05-01

    We show how a broad class of lattice spin-1/2 models with angular- and distance-dependent couplings can be realized with cold alkali atoms stored in optical or magnetic trap arrays. The effective spin-1/2 is represented by a pair of atomic ground states, and spin-spin interactions are obtained by admixing van der Waals interactions between fine-structure split Rydberg states with laser light. The strengths of the diagonal spin interactions as well as the "flip-flop," and "flip-flip" and "flop-flop" interactions can be tuned by exploiting quantum interference, thus realizing different spin symmetries. The resulting energy scales of interactions compare well with typical temperatures and decoherence time scales, making the exploration of exotic forms of quantum magnetism, including emergent gauge theories and compass models, accessible within state-of-the-art experiments. PMID:25978228

  14. Measurement of the electronic momentum distributions of Rydberg Stark states

    SciTech Connect

    Murray-Krezan, J.; Jones, R. R.

    2007-06-15

    Approximate momentum distributions of Rydberg electrons in static electric fields have been obtained using an improved impulsive momentum retrieval (IMR) technique. An imaging detector enables the measurement of half-cycle pulse (HCP) ionization probability across the spatial profile of a focused half-cycle pulse beam. By modulating the HCP amplitude we directly measure the derivative of the ionization vs HCP impulse curve, enabling the recovery of momentum distributions with better resolution than previously demonstrated with IMR. For example, for Stark states with small dipole moments, we observe predicted fine-structure in the projection of the momentum distribution along the Stark field axis. We use a semiclassical model to simulate the effect that the nonzero HCP duration has on our measurements. Good agreement between simulated and measured momentum distributions is obtained.

  15. Ultracold molecular Rydberg physics in a high density environment

    NASA Astrophysics Data System (ADS)

    Eiles, Matthew T.; Pérez-Ríos, Jesús; Robicheaux, F.; Greene, Chris H.

    2016-06-01

    Sufficiently high densities in Bose–Einstein condensates provide favorable conditions for the production of ultralong-range polyatomic molecules consisting of one Rydberg atom and a number of neutral ground state atoms. The chemical binding properties and electronic wave functions of these exotic molecules are investigated analytically via hybridized diatomic states. The effects of the molecular geometry on the system’s properties are studied through comparisons of the adiabatic potential curves and electronic structures for both symmetric and randomly configured molecular geometries. General properties of these molecules with increasing numbers of constituent atoms and in different geometries are presented. These polyatomic states have spectral signatures that lead to non-Lorentzian line-profiles.

  16. Fractional Quantum Hall Effect of Rydberg-Polaritons

    NASA Astrophysics Data System (ADS)

    Grusdt, Fabian; Fleischhauer, Michael; Otterbach, Johannes

    2012-02-01

    Dark-state-polaritons (DSP) are bosonic quasiparticles arising in the interaction of light with 3-level atoms under conditions of electromagnetically induced transparency (EIT). They can be exposed to artificial magnetic fields, strong enough to enter the lowest Landau level regime [Otterbach et. al., Phys. Rev. Lett. 104 (2010)]. We take into account interactions between the DSPs via Rydberg dipole-dipole interactions and discuss the realization of the ν=1/2-Laughlin state and its anyonic excitations (quasiholes) in such systems. The DSPs can be prepared in the correct total angular-momentum subspace by using orbital angular momentum light beams. A numerical and semi-analytical evaluation of the quasihole-gap is presented.

  17. Attractive Coulomb interaction of two-dimensional Rydberg excitons

    NASA Astrophysics Data System (ADS)

    Shahnazaryan, V.; Shelykh, I. A.; Kyriienko, O.

    2016-06-01

    We analyze theoretically the Coulomb scattering processes of highly excited excitons in the direct-band-gap semiconductor quantum wells. We find that contrary to the interaction of ground-state excitons, the electron and hole exchange interaction between excited excitons has an attractive character both for s - and p -type two-dimensional (2D) excitons. Moreover, we show that similar to the three-dimensional highly excited excitons, the direct interaction of 2D Rydberg excitons exhibits van der Waals-type long-range interaction. The results predict the linear growth of the absolute value of exchange interaction strength with an exciton principal quantum number and point the way towards enhancement of optical nonlinearity in 2D excitonic systems.

  18. Lensing effect of electromagnetically induced transparency involving a Rydberg state

    NASA Astrophysics Data System (ADS)

    Han, Jingshan; Vogt, Thibault; Manjappa, Manukumara; Guo, Ruixiang; Kiffner, Martin; Li, Wenhui

    2015-12-01

    We study the lensing effect experienced by a weak probe field under conditions of electromagnetically induced transparency (EIT) involving a Rydberg state. A Gaussian coupling beam tightly focused on a laser-cooled atomic cloud produces an inhomogeneity in the coupling Rabi frequency along the transverse direction and makes the EIT area acting like a gradient-index medium. We image the probe beam at the position where it exits the atomic cloud and observe that a red-detuned probe light is strongly focused with a greatly enhanced intensity whereas a blue-detuned one is defocused with a reduced intensity. Our experimental results agree very well with the numerical solutions of Maxwell-Bloch equations.

  19. Magic wavelengths for the 5 s -18 s transition in rubidium

    NASA Astrophysics Data System (ADS)

    Goldschmidt, E. A.; Norris, D. G.; Koller, S. B.; Wyllie, R.; Brown, R. C.; Porto, J. V.; Safronova, U. I.; Safronova, M. S.

    2015-03-01

    Magic wavelengths, for which there is no differential ac Stark shift for the ground and excited state of the atom, allow trapping of excited Rydberg atoms without broadening the optical transition. This is an important tool for implementing quantum gates and other quantum information protocols with Rydberg atoms, and reliable theoretical methods to find such magic wavelengths are thus extremely useful. We use a high-precision all-order method to calculate magic wavelengths for the 5 s -18 s transition of rubidium, and compare the calculation to experiment by measuring the light shift for atoms held in an optical dipole trap at a range of wavelengths near a calculated magic value.

  20. Density functional study of multiplicity-changing valence and Rydberg excitations of p-block elements: delta self-consistent field, collinear spin-flip time-dependent density functional theory (DFT), and conventional time-dependent DFT.

    PubMed

    Yang, Ke; Peverati, Roberto; Truhlar, Donald G; Valero, Rosendo

    2011-07-28

    A database containing 17 multiplicity-changing valence and Rydberg excitation energies of p-block elements is used to test the performance of density functional theory (DFT) with approximate density functionals for calculating relative energies of spin states. We consider only systems where both the low-spin and high-spin state are well described by a single Slater determinant, thereby avoiding complications due to broken-symmetry solutions. Because the excitations studied involve a spin change, they require a balanced treatment of exchange and correlation, thus providing a hard test for approximate density functionals. We test three formalisms for predicting the multiplicity-changing transition energies. First is the ΔSCF method; we also test time-dependent density functional theory (TDDFT), both in its conventional form starting from the low-spin state and in its collinear spin-flip form starting from the high-spin state. Very diffuse basis functions are needed to give a qualitatively correct description of the Rydberg excitations. The scalar relativistic effect needs to be considered when quantitative results are desired, and we include it in the comparisons. With the ΔSCF method, most of the tested functionals give mean unsigned errors (MUEs) larger than 6 kcal/mol for valence excitations and MUEs larger than 3 kcal/mol for Rydberg excitations, but the performance for the Rydberg states is much better than can be obtained with time-dependent DFT. It is surprising to see that the long-range corrected functionals, which have 100% Hartree-Fock exchange at large inter-electronic distance, do not improve the performance for Rydberg excitations. Among all tested density functionals, ΔSCF calculations with the O3LYP, M08-HX, and OLYP functionals give the best overall performance for both valence and Rydberg excitations, with MUEs of 2.1, 2.6, and 2.7 kcal/mol, respectively. This is very encouraging since the MUE of the CCSD(T) coupled cluster method with quintuple

  1. Interacting Rydberg atoms in an optical cavity to synthesize coherent collective states using dipole blockade

    NASA Astrophysics Data System (ADS)

    Kumar, Santosh; Sheng, Jiteng; Sedlacek, Jonathon; Ewel, Charlie; Fan, Haoquan; Shaffer, James

    2015-05-01

    We investigate the coherent manipulation of interacting Rydberg atoms placed inside a high-finesse optical cavity for the preparation of strongly coupled light-matter systems. We consider a four-level diamond scheme with one common Rydberg level. One side of the diamond is used to collectively excite the atoms to the Rydberg level using a pair of pulses. The other side of the diamond is used to produce a collective state that is close to resonance with a field mode of a high-finesse optical cavity. The interaction between Rydberg atoms creates a blockade which is useful for synthesizing the coherent collective state. We use numerical simulation to generate non-classical states of light and also investigate different decay mechanisms affecting this system. We also analyze our system in the case of two Rydberg excitations within the blockade volume. In this case, we show that more elaborate few excitation quantum states can be prepared in the cavity to observe interesting dynamics and analyze the correlation of the two-photon emission. This work is supported by the DARPA Quasar program by a grant through ARO, AFOSR and NSF.

  2. Enhancement of Rydberg-mediated single-photon nonlinearities by electrically tuned Förster resonances

    PubMed Central

    Gorniaczyk, H.; Tresp, C.; Bienias, P.; Paris-Mandoki, A.; Li, W.; Mirgorodskiy, I.; Büchler, H. P.; Lesanovsky, I.; Hofferberth, S.

    2016-01-01

    Mapping the strong interaction between Rydberg atoms onto single photons via electromagnetically induced transparency enables manipulation of light at the single-photon level and few-photon devices such as all-optical switches and transistors operated by individual photons. Here we demonstrate experimentally that Stark-tuned Förster resonances can substantially increase this effective interaction between individual photons. This technique boosts the gain of a single-photon transistor to over 100, enhances the non-destructive detection of single Rydberg atoms to a fidelity beyond 0.8, and enables high-precision spectroscopy on Rydberg pair states. On top, we achieve a gain larger than 2 with gate photon read-out after the transistor operation. Theory models for Rydberg polariton propagation on Förster resonance and for the projection of the stored spin-wave yield excellent agreement to our data and successfully identify the main decoherence mechanism of the Rydberg transistor, paving the way towards photonic quantum gates. PMID:27515278

  3. Heating and cooling of an ultra-cold neutral plasma by Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Tate, Duncan; Crockett, Ethan; Newell, Ryan

    2015-05-01

    We have experimentally demonstrated a mechanism for controlling the expansion rate of an ultra-cold neutral plasma (UNP) so that it is different from the value determined by the photo-ionizing laser frequency. We achieved this by adding Rydberg atoms to the UNP 10-20 ns after its creation. Specifically, we added nd5 / 2 state atoms with n = 24- 60 to UNPs with initial electron temperatures, Te , 0, in the range 10-250 K. The evidence is both indirect, from the change in the electron evaporation rate from the UNP, and direct, from the change in the asymptotic plasma expansion velocity, v0, measured using the time-of-flight spectrum of Rb+ ions. In addition, the results strongly support the existence of a ``bottleneck'' in the state distribution of Rydberg atoms formed by three body recombination (TBR) where the binding energy of the bottleneck state is Eb ~ 2 . 3 ×kBTe , 0 . Finally, we show that the amount of heating or cooling is linear in the number density of Rydberg atoms added to the UNP for small Rydberg densities, but saturates at higher densities to a value that is determined solely by the Rydberg binding energy. These results are in good general agreement with Monte-Carlo calculations. Funded by NSF and Colby College.

  4. Enhancement of Rydberg-mediated single-photon nonlinearities by electrically tuned Förster resonances.

    PubMed

    Gorniaczyk, H; Tresp, C; Bienias, P; Paris-Mandoki, A; Li, W; Mirgorodskiy, I; Büchler, H P; Lesanovsky, I; Hofferberth, S

    2016-01-01

    Mapping the strong interaction between Rydberg atoms onto single photons via electromagnetically induced transparency enables manipulation of light at the single-photon level and few-photon devices such as all-optical switches and transistors operated by individual photons. Here we demonstrate experimentally that Stark-tuned Förster resonances can substantially increase this effective interaction between individual photons. This technique boosts the gain of a single-photon transistor to over 100, enhances the non-destructive detection of single Rydberg atoms to a fidelity beyond 0.8, and enables high-precision spectroscopy on Rydberg pair states. On top, we achieve a gain larger than 2 with gate photon read-out after the transistor operation. Theory models for Rydberg polariton propagation on Förster resonance and for the projection of the stored spin-wave yield excellent agreement to our data and successfully identify the main decoherence mechanism of the Rydberg transistor, paving the way towards photonic quantum gates. PMID:27515278

  5. Collisional and electric-field ionization of laser-prepared Rydberg states in an ion trap mass spectrometer

    SciTech Connect

    Ramsey, J.M.; Whitten, W.B.; Goeringer, D.E.; Buckley, B.T.

    1990-01-01

    Rydberg states of rubidium are selectively generated by one and two photon laser excitation in a quadrupole ion trap mass spectrometer. Collisional and electric-field ionization is investigated in trapping device. CCl{sub 4} is studied as a target for ionization of Rydberg states through electron attachment.

  6. What is the electron temperature in a plasma which evolves from a sample of ultra-cold Rydberg atoms?

    NASA Astrophysics Data System (ADS)

    Tate, Duncan; Forest, Gabriel; Ward, Edwin; Goodsell, Anne

    2016-05-01

    Dense samples of cold Rydberg atoms evolve rapidly to an ultra-cold neutral plasma (UNP) due to ionizing collisions mediated by dipole forces, and other mechanisms. The subsequent plasma evolution is mediated by three-body recombination (TBR) of electrons and ions, and electron-Rydberg collisions, which can lead to de-excitation, excitation, and ionization of the Rydberg atoms. However, in contrast with UNPs formed by direct photoionization, the plasma evolves in the presence of a large reservoir of Rydberg atoms, and we have been investigating how this affects the UNP dynamics. Specifically, we excite cold Rb atoms in a MOT to a selected Rydberg state using a tuneable pulsed laser. We then measure the UNP expansion velocity using the ion time-of-flight spectra, as a function of the binding energy of the initial Rydberg state (Eb = 0 - 400 K), and the initial Rydberg density. Preliminary results show that the UNP expansion velocity, which is a manifestation of the effective electron temperature, has only a weak sensitivity to Eb, but is strongly dependent on the Rydberg density. Research supported by Colby College and NSF.

  7. Incoherent time evolution of Rydberg level populations in a Landau-Zener grid

    SciTech Connect

    Price, P.N.; Harmin, D.A.

    1993-05-01

    The time evolution of two intersecting groups of parallel energy levels, E{sub m} ({tau}) = p{tau} - m{epsilon} and E{sub m {prime}({tau}) = p{tau} + m{prime}{epsilon} = 0,1,2,..., p and {epsilon} constants), is considered as a model of state mixing of interacting Rydberg manifolds by a ramped electric field. Each intersection [m,m{prime}] of the triangular grid of level crossings is treated as an isolated 2-level Landau-Zener anticrossing at energy {1/2} (m{prime}-m){epsilon} with probabilities D and A = 1-D for diabatic and adiabatic transitions, respectively (interference effects are ignored here.) Beginning on the upward-going m = 0 level and following successive time steps {tau}{sup N} = {1/2} N{epsilon}/p (N = 0,1,2,...), a path analysis leads to a distribution of probabilities for arriving at an intersection [m,m{prime}] after N = m +m{prime} previous steps via ({sub m}{sup n}) possible paths. The fastest ramp rates (D {r_arrow} 1} evolve purely diabatically, remaining on the m = 0 level with probability D{sup N}; the slowest ramps (A {r_arrow} 1) follow a purely adiabatic path that switches between mid-grid levels m, m{prime} {approx} {1/2}N with probability A{sup N}. For any but the fastest ramps, however, there is a broad single-humped distribution with average energy E{sup (N)}= {1/2} {epsilon} {Sigma}{sub k}{sup N}=1 (D-A){sup k}- population is always concentrated near the center of the interaction region. Its spread in energy grows as N{sup 1/2} at large N but is narrower the larger is A.

  8. Coherent time evolution of Rydberg level populations in a Landau-Zener grid

    SciTech Connect

    Harmin, D.A.

    1993-05-01

    The time evolution groups of parallel energy levels (m, m{prime} = 0, 1, 2,...) is considered as a model of dynamic state mixing of interacting Rydberg manifolds by ramped electric fields used in selective field ionization (SFI). Each intersection [m, m{prime}] of the triangular grid of level crossings is treated as an isolated 2-level Landau-Zener anticrossing with amplitudes d and a for diabatic and adiabatic transitions, respectively ({vert_bar}d{vert_bar}{sup 2} + {vert_bar}a{vert_bar}{sup 2} = 1). Beginning on the uppermost upward-going level (m = 0) and following successive time steps {tau}{sup (N)} (N = 0,1,2,...), a path analysis leads to complex interference patterns among the many paths arriving at an intersection [m, m{prime}] after passing through N = m + m{prime} previous ones. The relative phase between any two paths is a multiple of the unit of action {var_phi} defined by the two pairs of adiabatic levels connecting four neighboring anticrossings. Compared to results from an analysis neglecting interference effects, there occurs here a general {open_quotes}emptying out{close_quotes} of population at the center of the interaction region (where the majority of paths lead). Most striking are resonances at high ramp rates (d {yields} 1), which with high probability enhance upward-going levels whose index m is an integral multiple of 27{pi}/{var_phi}. Though {var_phi} is sensitive to ramp rate, it is nevertheless expected that observed diabatic SFI signals should exhibit sequences of secondary peaks traceable to such resonances, which should not be assigned to extraneous initial states.

  9. Computing Rydberg Electron Transport Rates via Classical Periodic Orbits

    NASA Astrophysics Data System (ADS)

    Sattari, Sulimon; Mitchell, Kevin

    2015-05-01

    Electron transport properties of chaotic atomic systems are computable from classical periodic orbits. This technique allows for replacing a Monte Carlo simulation launching millions of orbits with a sum over tens or hundreds of properly chosen periodic orbits. Such computations are easiest to realize in sufficiently unstable systems dominated by a few short orbits. However, phase spaces exhibiting a mixture of chaos and regularity present a greater challenge, due to the rich dynamics in the vicinity of stable islands. Homotopic Lobe Dynamics (HLD) uses information encoded in the intersections of stable and unstable manifolds of a few orbits to compute almost all hyperbolic periodic orbits in a system. We compute the ionization rate for a Rydberg atom in parallel electric and magnetic fields. We apply HLD to compute orbits for parameters exhibiting both mixed and fully hyperbolic phase spaces. The ionization rate computed from periodic orbits converges exponentially to the true value as a function of highest period used. We then use periodic orbit continuation to accurately compute the ionization rate when the field strengths are perturbed. The ability to use periodic orbits in a mixed phase space could allow for studying transport in arbitrarily complex physical systems.

  10. Coherent dipole transport in a small grid of Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Yu, Hui; Robicheaux, F.

    2016-02-01

    We calculated the motion of one or two excitons through a small grid of Rydberg atoms. Both one- and two-dimensional grids were studied with the number of sites in a direction between 4 and 10. To mimic the possibility of nonperfect filling, calculations were performed with atoms randomly missing from sites. Results are presented for four qualitatively different situations. (1) The corners and edges, with the randomness of nonperfect filling, strongly affects the exciton motion and can pin the exciton. (2) For the case where a single exciton is simultaneously generated at two sites, the direction in which the exciton moves can be controlled by imprinting a phase difference on the two adjacent sites. (3) For the case where two excitons are generated at adjacent sites, calculations where a pair of excitons move through the grid are compared to the one exciton case to see whether exciton-exciton correlations are measurable. (4) The grid version of an exciton current can be defined by analogy to a continuity equation in one dimension and by using the analogy to a velocity operator in one, two, or three dimensions; for one dimension, the two definitions give similar results which means the direct measurement of the current in one dimension is possible.

  11. Observation of mixed singlet-triplet Rb2 Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Böttcher, F.; Gaj, A.; Westphal, K. M.; Schlagmüller, M.; Kleinbach, K. S.; Löw, R.; Liebisch, T. Cubel; Pfau, T.; Hofferberth, S.

    2016-03-01

    We present high-resolution spectroscopy of Rb2 ultralong-range Rydberg molecules bound by mixed singlet-triplet electron-neutral atom scattering. The mixing of the scattering channels is a consequence of the hyperfine interaction in the ground-state atom, as predicted recently by Anderson et al. [Phys. Rev. A 90, 062518 (2014), 10.1103/PhysRevA.90.062518]. Our experimental data enable the determination of the effective zero-energy singlet s -wave scattering length for Rb. We show that an external magnetic field can tune the contributions of the singlet and the triplet scattering channels and therefore the binding energies of the observed molecules. This mixing of molecular states via the magnetic field results in observed shifts of the molecular line which differ from the Zeeman shift of the asymptotic atomic states. Finally, we calculate molecular potentials using a full diagonalization approach including the p -wave contribution and all orders in the relative momentum k , and compare the obtained molecular binding energies to the experimental data.

  12. Many-body physics of Rydberg dark-state polaritons in the strongly interacting regime

    NASA Astrophysics Data System (ADS)

    Moos, Matthias; Höning, Michael; Unanyan, Razmik; Fleischhauer, Michael

    2015-11-01

    Coupling light to Rydberg states of atoms under conditions of electromagnetically induced transparency (EIT) leads to the formation of interacting quasiparticles, termed Rydberg polaritons. We derive a one-dimensional model describing the time evolution of these polaritons under paraxial propagation conditions. Specifically, we obtain a master equation governing the dynamics of Rydberg polaritons and identify conditions when it can essentially be described by an effective Hamiltonian of a single-species polariton. We verify this Hamiltonian by numerical two-excitation simulations. Under typical stationary EIT conditions it is impossible to reach the strongly interacting regime where long-range density-density correlations emerge. In contrast, by employing the time dependence of the control field the regime of strong interactions can be reached where the polaritons attain quasicrystalline order. We provide a physical explanation for the differences between stationary and time-dependent schemes.

  13. Neutralization distances of Ar^Z+ Rydberg ions interacting with solid surfaces

    NASA Astrophysics Data System (ADS)

    Majkic, M. D.; Nedeljkovic, N. N.; Galijas, S. M. D.

    2008-07-01

    We apply the recently developed time-symmetrized, two-state vector model to investigate the intermediate stages of the electron capture into the Rydberg states of multiply charged Ar^Z+ ions (core charge Z >> 1, principal quantum number n_A >> 1) escaping Al-solid surface at low velocity. The simple analytical formulae derived for the corresponding neutralization rates enable us to analyze the neutralization distances for the low-l Rydberg states (n_A,l_A,m_A), for different charge states Z of the ion. It is found that the inclusion of core polarization significantly reduces the neutralization distances. The neutralization distances for the highest Rydberg levels that can be populated in the vicinity of solid surface are in agreement with the data deduced from experiments in which the kinetic energy gain due to the image acceleration of the ions is measured.

  14. High-order harmonic generation with Rydberg atoms by using an intense few-cycle pulse

    NASA Astrophysics Data System (ADS)

    Zhai, Zhen; Zhu, Qiren; Chen, Jing; Yan, Zong-Chao; Fu, Panming; Wang, Bingbing

    2011-04-01

    We demonstrate that high-order harmonic generation (HHG) with both high cutoff frequency and high conversion efficiency can be realized by using a Rydberg atom in a few-cycle laser pulse. This is because a Rydberg state has a large electron orbital radius and small binding energy; therefore an electron in the Rydberg state can be ionized easily and accelerated directly toward the core under the interaction of a few-cycle laser pulse, leading to emission of harmonic photons. In this case, the tunneling process of the electron is not involved and, hence, the conversion efficiency and the cutoff frequency of harmonic generation can be higher than that predicted by the conventional three-step model.

  15. Surface-electrode decelerator and deflector for Rydberg atoms and molecules

    NASA Astrophysics Data System (ADS)

    Allmendinger, P.; Deiglmayr, J.; Agner, J. A.; Schmutz, H.; Merkt, F.

    2014-10-01

    A surface-electrode decelerator and deflector for Rydberg atoms and molecules has been developed with the goal of performing collisional experiments. Translationally cold H2 molecules in a supersonic beam were excited to Rydberg-Stark states of principal quantum number n =31, loaded into electric traps moving at a predetermined speed above the surface of a bent printed circuit board, decelerated, and deflected from the original direction of the supersonic beam by an angle of 10∘. The phase-space characteristics of the deflected beam were characterized by measuring the time-of-flight distribution and images of the Rydberg molecules and comparing them to the results of numerical particle-trajectory simulations. More than 1000 H2 molecules were deflected per experimental cycle at a repetition rate of 25 Hz. The phase-space characteristics of the deflector make it attractive to study ion-molecule reactions at low collision energies.

  16. Measurement of holmium Rydberg series through magneto-optical trap depletion spectroscopy

    NASA Astrophysics Data System (ADS)

    Hostetter, J.; Pritchard, J. D.; Lawler, J. E.; Saffman, M.

    2015-01-01

    We report measurements of the absolute excitation frequencies of 165Ho 4 f116 s n s and 4 f116 s n d odd-parity Rydberg series. The states are detected through depletion of a magneto-optical trap via a two-photon excitation scheme. Measurements of 162 Rydberg levels in the range n =40 -101 yield quantum defects well described by the Rydberg-Ritz formula. We observe a strong perturbation in the n s series around n =51 due to an unidentified interloper at 48515.47(4) cm-1. From the series convergence, we determine the first ionization potential EIP=48565.910 (3 ) cm-1, which is three orders of magnitude more accurate than previous work. This work is an important step towards using Ho atoms for collective encoding of a quantum register.

  17. Sub-Poissonian Statistics of Jamming Limits in Ultracold Rydberg Gases

    NASA Astrophysics Data System (ADS)

    Sanders, Jaron; Jonckheere, Matthieu; Kokkelmans, Servaas

    2015-07-01

    Several recent experiments have established by measuring the Mandel Q parameter that the number of Rydberg excitations in ultracold gases exhibits sub-Poissonian statistics. This effect is attributed to the Rydberg blockade that occurs due to the strong interatomic interactions between highly excited atoms. Because of this blockade effect, the system can end up in a state in which all particles are either excited or blocked: a jamming limit. We analyze appropriately constructed random-graph models that capture the blockade effect, and derive formulae for the mean and variance of the number of Rydberg excitations in jamming limits. This yields an explicit relationship between the Mandel Q parameter and the blockade effect, and comparison to measurement data shows strong agreement between theory and experiment.

  18. Possibility of triple magic trapping of clock and Rydberg states of divalent atoms in optical lattices

    NASA Astrophysics Data System (ADS)

    Topcu, T.; Derevianko, A.

    2016-07-01

    We predict the possibility of ‘triply magic’ optical lattice trapping of neutral divalent atoms. In such a lattice, the {}1{{{S}}}0 and {}3{{{P}}}0 clock states and an additional Rydberg state experience identical optical potentials, fully mitigating detrimental effects of the motional decoherence. In particular, we show that this triply magic trapping condition can be satisfied for Yb atom at optical wavelengths and for various other divalent systems (Ca, Mg, Hg and Sr) in the UV region. We assess the quality of triple magic trapping conditions by estimating the probability of excitation out of the motional ground state as a result of the excitations between the clock and the Rydberg states. We also calculate trapping laser-induced photoionization rates of divalent Rydberg atoms at magic frequencies. We find that such rates are below the radiative spontaneous-emission rates, due to the presence of Cooper minima in photoionization cross-sections.

  19. Observation of Rydberg-Atom Macrodimers: Micrometer-Sized Diatomic Molecules.

    PubMed

    Saßmannshausen, Heiner; Deiglmayr, Johannes

    2016-08-19

    Long-range metastable molecules consisting of two cesium atoms in high Rydberg states have been observed in an ultracold gas. A sequential three-photon two-color photoassociation scheme is employed to form these molecules in states, which correlate to np(n+1)s dissociation asymptotes. Spectral signatures of bound molecular states are clearly resolved at the positions of avoided crossings between long-range van der Waals potential curves. The experimental results are in agreement with simulations based on a detailed model of the long-range multipole-multipole interactions of Rydberg-atom pair states. We show that a full model is required to accurately predict the occurrence of bound Rydberg macrodimers. The macrodimers are distinguished from repulsive molecular states by their behavior with respect to spontaneous ionization and possible decay channels are discussed. PMID:27588856

  20. Van der Waals interactions among alkali Rydberg atoms with excitonic states

    NASA Astrophysics Data System (ADS)

    Zoubi, Hashem

    2015-09-01

    We investigate the influence of the appearance of excitonic states on van der Waals interactions among two Rydberg atoms. The atoms are assumed to be in different Rydberg states, e.g., in the | {ns}> and | {np}> states. The resonant dipole-dipole interactions yield symmetric and antisymmetric excitons, with energy splitting that give rise to new resonances as the atoms approach each other. Only away from these resonances can the van der Waals coefficients, C6sp, be defined. We calculate the C6 coefficients for alkali atoms and present the results for lithium by applying perturbation theory. At short interatomic distances of several μ {{m}}, we show that the widely used simple model of two-level systems for excitons in Rydberg atoms breaks down, and the correct representation implies multi-level atoms. Even though, at larger distances one can keep the two-level systems but in including van der Waals interactions among the atoms .

  1. Vibrational autoionization and predissociation in high Rydberg states of nitric oxide

    SciTech Connect

    Pratt, S.T.

    1998-05-01

    New results on the competition between autoionization and predissociation in the high Rydberg states of nitric oxide are presented. These results provide insight into the earlier work of Park {ital et al.} [Phys. Rev. Lett. {bold 76}, 1591 (1996)] that shows evidence for substantial mixing between Rydberg series and ionization continua with even and odd orbital angular momenta (l). New data based on fluorescence-dip spectroscopy, detection of neutral predissociation products, and photoelectron spectroscopy suggest that the A{sup {prime}}{sup 2}{Sigma}{sup +} and I{sup 2}{Sigma}{sup +} dissociative valence states play an important role in this l mixing. Zeeman splittings observed in a magnetic bottle electron spectrometer also result in an improvement in the assignment of these high Rydberg states. {copyright} {ital 1998 American Institute of Physics.}

  2. Time Evolution of High-l Stark States in Cold Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Wang, Limei; Zhang, Hao; Zhang, Linjie; Wang, Yong; Bao, Shanxia; Li, Changyong; Zhao, Jianming; Jia, Suotang

    2014-11-01

    The high-l Rydberg Stark states are populated by the state transfer from initial prepared nS Rydberg state via avoided crossings induced by a weak electric-field pulse, and investigated by the state selective field ionization method in a cesium standard magneto-optical trap. The dependences of the transfer rate, given by the ratio of the number of high-l Stark states to all atoms, on the strength and holding time of electric-field pulse are investigated and compared with those with additional ions. The results show that the time evolution of high-l Stark states strongly depends on the electric-field strength, and is affected by the additional ions at relatively weaker field (1.51 V/cm here). The density of Rydberg atoms has a minor effect on the characteristic time of evolution process.

  3. Vibrational autoionization and predissociation in high Rydberg states of nitric oxide

    NASA Astrophysics Data System (ADS)

    Pratt, S. T.

    1998-05-01

    New results on the competition between autoionization and predissociation in the high Rydberg states of nitric oxide are presented. These results provide insight into the earlier work of Park et al. [Phys. Rev. Lett. 76, 1591 (1996)] that shows evidence for substantial mixing between Rydberg series and ionization continua with even and odd orbital angular momenta (l). New data based on fluorescence-dip spectroscopy, detection of neutral predissociation products, and photoelectron spectroscopy suggest that the A' 2Σ+ and I 2Σ+ dissociative valence states play an important role in this l mixing. Zeeman splittings observed in a magnetic bottle electron spectrometer also result in an improvement in the assignment of these high Rydberg states.

  4. Vibrational Autoionization and Predissociation in High Rydberg States of Nitric Oxide

    NASA Astrophysics Data System (ADS)

    Pratt, S. T.

    1998-05-01

    New results on the competition between autoionization and predissociation in the high Rydberg states of NO are presented. These results provide insight into the earlier work of H. Park et al. [Phys. Rev. Lett. 76, 1591 (1996)] that show evidence for substantial mixing between Rydberg series and ionization continua with even and odd orbital angular momenta. New data based on fluorescence-dip spectroscopy, detection of neutral predissociation products, and photoelectron spectroscopy suggest that the A' ^2Σ ^+ and I ^2Σ ^+ dissociative valence states play an important role in this mixing. As an example, the ionization and dissociation efficiencies of the nf levels are found to depend strongly on whether the total angular momentum minus spin, N, is even or odd, indicating predissociation via a ^2Σ ^+ state. Zeeman splittings observed in a magnetic bottle electron spectrometer also result in an improvement in the assignment of these high Rydberg states.

  5. Resonant Rydberg Dressing of Alkaline-Earth Atoms via Electromagnetically Induced Transparency

    NASA Astrophysics Data System (ADS)

    Gaul, C.; DeSalvo, B. J.; Aman, J. A.; Dunning, F. B.; Killian, T. C.; Pohl, T.

    2016-06-01

    We develop an approach to generate finite-range atomic interactions via optical Rydberg-state excitation and study the underlying excitation dynamics in theory and experiment. In contrast to previous work, the proposed scheme is based on resonant optical driving and the establishment of a dark state under conditions of electromagnetically induced transparency (EIT). Analyzing the driven dissipative dynamics of the atomic gas, we show that the interplay between coherent light coupling, radiative decay, and strong Rydberg-Rydberg atom interactions leads to the emergence of sizable effective interactions while providing remarkably long coherence times. The latter are studied experimentally in a cold gas of strontium atoms for which the proposed scheme is most efficient. Our measured atom loss is in agreement with the theoretical prediction based on binary effective interactions between the driven atoms.

  6. Hydrogen Balmer series measurements and determination of Rydberg's constant using two different spectrometers

    NASA Astrophysics Data System (ADS)

    Amrani, D.

    2014-07-01

    This paper investigates the use of two different methods, the optical and the computer-aided diffraction-grating spectrometer, to measure the wavelength of visible lines of Balmer series from the hydrogen atomic spectrum and estimate the value of Rydberg's constant. Analysis and interpretation of data showed that both methods, despite their difference in terms of the type of equipment used, displayed good performance in terms of precision of measurements of wavelengths of spectral lines. A comparison was carried out between the experimental value of Rydberg's constant obtained with both methods and the accepted value. The results of Rydberg's constant obtained with both the optical and computer-aided spectrometers were 1.099 28 × 10-7 m-1 and 1.095 13 × 10-7 m-1 with an error difference of 0.17% and 0.20% compared to the accepted value 1.097 373 × 10-7 m-1, respectively.

  7. Accessing Rydberg-dressed interactions using many-body Ramsey dynamics

    NASA Astrophysics Data System (ADS)

    Mukherjee, Rick; Killian, Thomas; Hazzard, Kaden

    2016-05-01

    We demonstrate that Ramsey spectroscopy can be used to observe Rydberg-dressed interactions in a many-body system. Our scheme operates comfortably within experimentally measured lifetimes, and accesses a regime where quantum superpositions are crucial. We build a spin-1/2 from one level that is Rydberg-dressed and another that is not. These levels may be hyperfine or long-lived electronic states. An Ising spin model governs the Ramsey dynamics, for which we derive an exact solution. Due to the structure of Rydberg interactions, the dynamics differs significantly from that in other spin systems. As one example, spin echo can increase the rate at which coherence decays. The results are relevant for the current ongoing experiments, including those at Rice University.

  8. Resonant Rydberg Dressing of Alkaline-Earth Atoms via Electromagnetically Induced Transparency.

    PubMed

    Gaul, C; DeSalvo, B J; Aman, J A; Dunning, F B; Killian, T C; Pohl, T

    2016-06-17

    We develop an approach to generate finite-range atomic interactions via optical Rydberg-state excitation and study the underlying excitation dynamics in theory and experiment. In contrast to previous work, the proposed scheme is based on resonant optical driving and the establishment of a dark state under conditions of electromagnetically induced transparency (EIT). Analyzing the driven dissipative dynamics of the atomic gas, we show that the interplay between coherent light coupling, radiative decay, and strong Rydberg-Rydberg atom interactions leads to the emergence of sizable effective interactions while providing remarkably long coherence times. The latter are studied experimentally in a cold gas of strontium atoms for which the proposed scheme is most efficient. Our measured atom loss is in agreement with the theoretical prediction based on binary effective interactions between the driven atoms. PMID:27367387

  9. GHz Rabi Flopping to Rydberg States in Hot Atomic Vapor Cells

    SciTech Connect

    Huber, B.; Baluktsian, T.; Schlagmueller, M.; Koelle, A.; Kuebler, H.; Loew, R.; Pfau, T.

    2011-12-09

    We report on the observation of Rabi oscillations to a Rydberg state on a time scale below 1 ns in thermal rubidium vapor. We use a bandwidth-limited pulsed excitation and observe up to 6 full Rabi cycles within a pulse duration of {approx}4 ns. We find good agreement between the experiment and numerical simulations based on a surprisingly simple model. This result shows that fully coherent dynamics with Rydberg states can be achieved even in thermal atomic vapor, thus suggesting small vapor cells as a platform for room-temperature quantum devices. Furthermore, the result implies that previous coherent dynamics in single-atom Rydberg gates can be accelerated by 3 orders of magnitude.

  10. Photonic controlled-phase gates through Rydberg blockade in optical cavities

    NASA Astrophysics Data System (ADS)

    Das, Sumanta; Grankin, Andrey; Iakoupov, Ivan; Brion, Etienne; Borregaard, Johannes; Boddeda, Rajiv; Usmani, Imam; Ourjoumtsev, Alexei; Grangier, Philippe; Sørensen, Anders S.

    2016-04-01

    We propose a scheme for high-fidelity photonic controlled-phase gates using a Rydberg blockade in an ensemble of atoms in an optical cavity. The gate operation is obtained by first storing a photonic pulse in the ensemble and then scattering a second pulse from the cavity, resulting in a phase change depending on whether the first pulse contained a single photon. We show that the combination of a Rydberg blockade and optical cavities effectively enhances the optical nonlinearity created by the strong Rydberg interaction and makes the gate operation more robust. The resulting gate can be implemented with cavities of moderate finesse, allowing for highly efficient processing of quantum information encoded in photons. As an illustration, we show how the gate can be employed to increase the communication rate of quantum repeaters based on atomic ensembles.

  11. Dielectronic Recombination, Autoionization and Non-Adiabatic Core Polarization of Rydberg Two-Electron Atoms

    NASA Astrophysics Data System (ADS)

    Nunkaew, Jirakan

    In this dissertation, I study the structure and dynamics of Rydberg two-electron atoms. Specifically, I study the core polarization effect of the Rydberg electron on the ground state ion of strontium and the autoionization of barium atoms in an external static field in the low field regime. The autoionization studies show that it is possible to measure the contribution to dielectronic recombination (DR) of energetically unresolved high ℓ states by measuring the recombination rate as a function of electric field. I also present the experimental observation that the ejected electrons from autoionizing states in an electric field have a directional preference that depends on the orientation of the Rydberg Stark state wavefunctions. Finally, I present the spectroscopy of the Stark autoionizing states in the low field regime using a high resolution dye-amplified diode laser.

  12. Double-resonance spectroscopy of the high Rydberg states of HCO. III. Multiple pathways in the vibrational autoionization of the bending overtone

    NASA Astrophysics Data System (ADS)

    Mayer, Eric E.; Hedderich, Hartmut G.; Grant, Edward R.

    1998-05-01

    Ultraviolet first-photon absorption selects individual rotational levels in the Renner-Teller split (020) vibronic band system in the 3pπ 2Π Rydberg state of HCO. These gateway states serve as originating levels for vertical second-photon transitions to vibrationally autoionizing Rydberg series converging to individual rotational levels associated with the (0200) and (0220) states of HCO+. Linewidths of assigned series convey information on autoionization dynamics. Resonances throughout the (020) autoionization spectrum match sharp profiles seen earlier for series converging to HCO+(010). Linewidths for autoionization via relaxation both of the bending fundamental and its overtone are measurably narrower than resonances built on CO stretch, (001), which indicates that mode-selectivity inhibiting bending autoionization relative to stretch extends to the bending overtone. Features in the (020) spectrum that fall below the threshold energy for decay by autoionization to the (010) continuum appear with diminished intensity and yet narrower linewidth. This provides evidence that vibrational autoionization in HCO conforms with a Δv=1 propensity rule that favors relaxation of (020) states to the (010) continuum over the two-quantum decay to produce HCO+(000). Analysis of detailed line shapes and intensities associated with individual vibrational angular momentum components of the relaxing-core overtone point to the way in which vibrational and orbital-electronic symmetries factor in the bound molecule and cation plus free electron, and fix the order in vibrational coordinates of necessary coupling terms.

  13. Rydberg Excitation of Single Atoms for Applications in Quantum Information and Metrology

    SciTech Connect

    Hankin, Aaron Michael

    2014-08-01

    With the advent of laser cooling and trapping, neutral atoms have become a foundational source of accuracy for applications in metrology and are showing great potential for their use as qubits in quantum information. In metrology, neutral atoms provide the most accurate references for the measurement of time and acceleration. The unsurpassed stability provided by these systems make neutral atoms an attractive avenue to explore applications in quantum information and computing. However, to fully investigate the eld of quantum information, we require a method to generate entangling interactions between neutral-atom qubits. Recent progress in the use of highly-excited Rydberg states for strong dipolar interactions has shown great promise for controlled entanglement using the Rydberg blockade phenomenon. I report the use of singly-trapped 133Cs atoms as qubits for applications in metrology and quantum information. Each atom provides a physical basis for a single qubit by encoding the required information into the ground-state hyper ne structure of 133Cs. Through the manipulation of these qubits with microwave and optical frequency sources, we demonstrate the capacity for arbitrary single-qubit control by driving qubit rotations in three orthogonal directions on the Bloch sphere. With this control, we develop an atom interferometer that far surpasses the force sensitivity of other approaches by applying the well-established technique of lightpulsed atom-matterwave interferometry to single atoms. Following this, we focus on two-qubit interactions using highly-excited Rydberg states. Through the development of a unique single-photon approach to Rydberg excitation using an ultraviolet laser at 319 nm, we observe the Rydberg blockade interaction between atoms separated by 6.6(3) m. Motivated by the observation of Rydberg blockade, we study the application of Rydberg-dressed states for a quantum controlled-phase gate. Using a realistic simulation of the

  14. Rydberg Excitation of Single Atoms for Applications in Quantum Information and Metrology

    NASA Astrophysics Data System (ADS)

    Hankin, Aaron Michael

    With the advent of laser cooling and trapping, neutral atoms have become a foundational source of accuracy for applications in metrology and are showing great potential for their use as qubits in quantum information. In metrology, neutral atoms provide the most accurate references for the measurement of time and acceleration. The unsurpassed stability provided by these systems make neutral atoms an attractive avenue to explore applications in quantum information and computing. However, to fully investigate the field of quantum information, we require a method to generate entangling interactions between neutral-atom qubits. Recent progress in the use of highly-excited Rydberg states for strong dipolar interactions has shown great promise for controlled entanglement using the Rydberg blockade phenomenon. I report the use of singly-trapped cesium-133 atoms as qubits for applications in metrology and quantum information. Each atom provides a physical basis for a single qubit by encoding the required information into the ground-state hyperfine structure of cesium-133. Through the manipulation of these qubits with microwave and optical frequency sources, we demonstrate the capacity for arbitrary single-qubit control by driving qubit rotations in three orthogonal directions on the Bloch sphere. With this control, we develop an atom interferometer that far surpasses the force sensitivity of other approaches by applying the well-established technique of light-pulsed atom-matterwave interferometry to single atoms. Following this, we focus on two-qubit interactions using highly-excited Rydberg states. Through the development of a unique single-photon approach to Rydberg excitation using an ultraviolet laser at 319 nm, we observe the Rydberg blockade interaction between atoms separated by 6.6(3) μm. Motivated by the observation of Rydberg blockade, we study the application of Rydberg-dressed states for a quantum controlled-phase gate. Using a realistic simulation of the

  15. Photodissociation Efficiency Spectroscopy Study of the Rydberg Excited Ion-Pair States of Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Feng, Qiang; Xu, Yun-Feng; Sun, Jin-Da; Tian, Shan-Xi; Shan, Xiao-Bin; Liu, Fu-Yi; Sheng, Liu-Si

    2009-10-01

    Photodissociation efficiency spectrum of anionic oxygen atom produced via ion-pair dissociations of carbon dioxide is recorded by means of the synchrotron radiation excitation (XUV photon energy 17.40-20.00 eV). The present spectrum is assigned as the Rydberg-like excited ion-pair states, i.e., Tanaka-Ogawa and Henning series, tilde C2Σg+ (CO+2) vibrational ground-state and excitation series. Three Rydberg series, npσu, npπu, and nfu, converging to tilde C2Σg+ (0, 0, 0), show the higher cross sections.

  16. Effects of Hyperfine Mixing of Rydberg-ground molecular potentials in Rb

    NASA Astrophysics Data System (ADS)

    Maclennan, Jamie; Ramos, Andira; Thaicharoen, Nithiwadee; Raithel, Georg

    2016-05-01

    Rydberg molecules formed by the scattering between a ground-state atom and a Rydberg electron can offer new insight into the nature of atomic interactions and molecular structure. Shallow bound states that arise from hyperfine-induced mixing of singlet and triplet channels have recently been predicted and observed for P-states in Cs and S-states in 87 Rb. Here we present progress toward characterizing Rb (nD + 5 S1/2) molecules, including a comparison of the hyperfine-mixing effects between the two isotopes (85 Rb and 87 Rb).

  17. Anisotropic emission of neutral atoms: evidence of an anisotropic Rydberg sheath in nanoplasma

    NASA Astrophysics Data System (ADS)

    Rajeev, R.; Madhu Trivikram, T.; Rishad, K. P. M.; Krishnamurthy, M.

    2015-02-01

    Intense laser-produced plasma is a complex amalgam of ions, electrons and atoms both in ground and excited states. Little is known about the spatial composition of the excited states that are an integral part of most gaseous or cluster plasma. In cluster-plasma, Rydberg excitations change the charge composition of the ions through charge transfer reactions and shape the angular distributions. Here, we demonstrate a non-invasive technique that reveals the anisotropic Rydberg excited cluster sheath by measuring anisotropy in fast neutral atoms. The sheath is stronger in the direction of light polarization and the enhanced charge transfer by the excited clusters results in larger neutralization.

  18. Survival of Rydberg atoms in intense laser fields and the role of nondipole effects

    NASA Astrophysics Data System (ADS)

    Klaiber, Michael; Dimitrovski, Darko

    2015-02-01

    We consider the interaction of Rydberg atoms with strong infrared laser pulses using an approach based on the Magnus expansion of the time evolution operator. First-order corrections beyond the electric dipole approximation are also included in the theory. We illustrate the dynamics of the interaction at the parameters of the experiment [Eichmann et al., Phys. Rev. Lett. 110, 203002 (2013), 10.1103/PhysRevLett.110.203002]. It emerges that the depletion of Rydberg atoms in this regime comes predominantly from the nondipole effects.

  19. Spin-charge separation of dark-state polaritons in a Rydberg medium

    NASA Astrophysics Data System (ADS)

    Shi, Xiao-Feng; Svetlichnyy, P.; Kennedy, T. A. B.

    2016-04-01

    The propagation of light fields through a quasi one-dimensional cold atomic gas, exciting atomic Rydberg levels of large principal quantum number under conditions of electromagnetically induced transparency, can lead to a stable two-mode Luttinger liquid system. Atomic van der Waals interactions induce a coupling of bosonic field modes that display both photonic and atomic character, the Rydberg dark-state polaritons (RDPs). It is shown that by tunable control of the van der Waals coupling, the RDP may decouple into independent ‘spin’ and ‘charge’ fields which propagate at different speeds, analogous to spin-charge separation of electrons in a one-dimensional metal.

  20. The interaction potential of NO-H2 in ground and A Rydberg state

    NASA Astrophysics Data System (ADS)

    Pajón-Suárez, Pedro; Valentín-Rodríguez, Mónica; Hernández-Lamoneda, Ramón

    2016-08-01

    The interaction potential for the ground and A Rydberg state of NO-H2 has been calculated using high level ab initio methods. The complex is very floppy in nature and large amplitude motions are expected to characterize its dynamics. The ground state is characterized by two very close-lying states which exhibit crossings. By analogy with other complexes the Rydberg state is characterized by much smaller well depth and larger intermolecular distance. We compare with model potentials used in previous molecular dynamics simulations of photoexcitation and relaxation and conclude on the importance of performing new studies.

  1. Properties of atoms in molecules: Transition probabilities

    NASA Astrophysics Data System (ADS)

    Bader, R. F. W.; Bayles, D.; Heard, G. L.

    2000-06-01

    The transition probability for electric dipole transitions is a measurable property of a system and is therefore, partitionable into atomic contributions using the physics of a proper open system. The derivation of the dressed property density, whose averaging over an atomic basin yields the atomic contribution to a given oscillator strength, is achieved through the development of perturbation theory for an open system. A dressed density describes the local contribution resulting from the interaction of a single electron at some position r, as determined by the relevant observable, averaged over the motions of all of the remaining particles in the system. In the present work, the transition probability density expressed in terms of the relevant transition density, yields a local measure of the associated oscillator strength resulting from the interaction of the entire molecule with a radiation field. The definition of the atomic contributions to the oscillator strength enables one to determine the extent to which a given electronic or vibrational transition is spatially localized to a given atom or functional group. The concepts introduced in this article are applied to the Rydberg-type transitions observed in the electronic excitation of a nonbonding electron in formaldehyde and ammonia. The atomic partitioning of the molecular density distribution and of the molecular properties by surfaces of zero flux in the gradient vector field of the electron density, the boundary condition defining the physics of a proper open system, is found to apply to the density distributions of the excited, Rydberg states.

  2. Rydberg gas theory of a glow discharge plasma: II. Electrode kinetics (probe theory) and the thermal rate constant for Symmetrical charge transfer involving Rydberg atoms of Ar.

    PubMed

    Mason, Rod S

    2010-04-21

    A steady state chemical kinetic model is developed to describe the conduction of electrical current between two probes, of relatively large surface area, immersed in a fast flowing plasma by the mechanism of charge transfer through a gas of Rydberg atoms. It correctly predicts the shape of current-voltage profiles which are similar to those of Langmuir, or floating double probe measurements. The difference is that the plateau current at the probe reflects the transport limited ion current at the cathodic electrode, even when the probe is being scanned in the anodic region. The sharp gradient leading up to the plateau of the I-V curve is associated with the field dependence of the efficiency of Rydberg atom ionisation, not the electron temperature. This approach gives a good qualitative explanation of experimental behaviour over a wide range of probe bias voltages and includes the occurrence of electron impact ionisation at the anode. It also gives a value for the thermal rate coefficient of symmetrical charge transfer between Rydberg atoms of Ar (8.2 x 10(-7) molecule(-1) cm(3) s(-1), at 313 K; plasma density approximately = 10(10) atoms cm(-3), total pressure = 2.7 mbar). PMID:20358036

  3. FUSE Measurements of Rydberg Bands of Interstellar CO between 925 and 1150 Å

    NASA Astrophysics Data System (ADS)

    Sheffer, Y.; Federman, S. R.; Andersson, B.-G.

    2003-11-01

    We report the detection of 11 Rydberg bands of CO in FUSE spectra of the sight line toward HD 203374A. Eight of these electronic bands are seen in the interstellar medium for the first time. Our simultaneous fit of five non-Rydberg A-X bands together with the strongest Rydberg band of CO, C-X (0-0), yields a four-component cloud structure toward the stellar target. With this model we synthesize the other Rydberg bands in order to derive their oscillator strengths. We find that the strength of some bands was underestimated in previously published results from laboratory measurements. The implication is important for theoretical calculations of the abundance of interstellar CO, because its dissociation and self-shielding depend on oscillator strengths for these bands. Based on observations made with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer (FUSE), which is operated for NASA by the Johns Hopkins University under NASA contract NAS5-32985.

  4. Field ionization process of Eu 4f76snp Rydberg states

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Shen, Li; Dai, Chang-Jian

    2015-11-01

    The field ionization process of the Eu 4f76snp Rydberg states, converging to the first ionization limit, 4f76s 9S4, is systematically investigated. The spectra of the Eu 4f76snp Rydberg states are populated with three-step laser excitation, and detected by electric field ionization (EFI) method. Two different kinds of the EFI pulses are applied after laser excitation to observe the possible impacts on the EFI process. The exact EFI ionization thresholds for the 4f76snp Rydberg states can be determined by observing the corresponding EFI spectra. In particular, some structures above the EFI threshold are found in the EFI spectra, which may be interpreted as the effect from black body radiation (BBR). Finally, the scaling law of the EFI threshold for the Eu 4f76snp Rydberg states with the effective quantum number is built. Project supported by the National Natural Science Foundation of China (Grant Nos. 11004151 and 11174218).

  5. Preparation for Acceleration and Deceleration of Cold Rydberg Atoms in the Field of a Charged Wire

    NASA Astrophysics Data System (ADS)

    Goodsell, Anne; Nawarat, Poomirat; Harper, W. Colleen

    2015-05-01

    We are preparing for experiments using cold Rydberg atoms in linear Stark states. We cool and launch Rb atoms at 2-12 m/s toward a charged wire with a cylindrically-symmetric electric field. The cold cloud will be illuminated in mid-flight to promote atoms into the desired Rydberg state (e.g. n = 33-40). With a three-photon sequence we will access nf states and the nearby manifolds (parabolic quantum number 0 <=n1 <= (n -4)) with linear Stark shifts. This requires specific detuning of the the excitation laser, which allows us to selectively compare states that are strongly accelerated to states that are strongly decelerated. With the wire at +10 V, atoms launched at 10 m/s, and excitation near 750 μm from the wire, the displacement during the Rydberg lifetime (e.g. n = 35, τ = 30 μs) will be 200-300 μm farther for extreme attracted states (n1 = 0) than for extreme repelled states (n1 = 31). Detection will occur by spatially-dependent field ionization. Observations of atoms with zero angular momentum around the wire can be extended to atoms with nonzero angular momentum and also to study the dynamics of Rydberg atoms with a quadratic Stark shift, building on previous work with ground-state atoms. (Current address: Rensselaer Polytechnic Institute, Troy, NY).

  6. Comparative study on atomic and molecular Rydberg-state excitation in strong infrared laser fields

    NASA Astrophysics Data System (ADS)

    Lv, Hang; Zuo, Wanlong; Zhao, Lei; Xu, Haifeng; Jin, Mingxing; Ding, Dajun; Hu, Shilin; Chen, Jing

    2016-03-01

    Rydberg-state excitation of atoms in strong infrared laser fields provides a new complementary aspect of the perspective of atom-strong field interactions. In this article, we perform an experimental and theoretical study on the corresponding process of diatomic molecules, N2 and O2. We show that neutral molecules can also survive strong 800-nm laser fields in high Rydberg states, while their behavior is remarkably different in comparison with their companion atoms, Ar and Xe. The Rydberg excitation of N2 generally behaves similarly to Ar, while that of O2 is more significantly suppressed than the ionization compared to Xe in a high intensity region, which can be understood in the frame of a semiclassical picture, together with their different structures of molecular orbitals. However, distinct quantum features in the Rydberg excitation processes that are apparently beyond the semiclassical picture have been identified, i.e., the less suppressed probability of O2 at low intensity and the oscillation behavior of the ratio between N2 and Ar, indicating that our understanding of the relevant physics is still far from complete.

  7. Direct measurement of the van der Waals interaction between two Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Browaeys, A.

    2013-05-01

    This talk will report on the direct measurement of the van der Waals interaction between two isolated, single Rydberg atoms separated by a controlled distance of a few micrometers. By working in a regime where the single-atom Rabi frequency of the laser used for excitation to the Rydberg state is comparable to the interaction energy, we observe a partial Rydberg blockade, whereby the time-dependent populations of the various two-atom states exhibit coherent oscillations with several frequencies. A quantitative comparison of the data with a simple model based on the optical Bloch equations allows us to extract the van der Waals energy, and to observe its characteristic C6 /R6 dependence. The magnitude of the measured C6 coefficient agrees well with ab-initio calculations, and we observe its dramatic increase with the principal quantum number n of the Rydberg state. Our results demonstrate a good degree of experimental control, which opens interesting perspectives in quantum information processing and quantum simulation using long-range interactions between atoms.

  8. Phase dependent excitation of Rydberg atoms in non-zero average fields

    NASA Astrophysics Data System (ADS)

    Magnuson, Eric; Carrat, Vincent; Gallagher, Tom

    2016-05-01

    The final energy of an electron excited to a high lying Rydberg state in the presence of a microwave (MW) field shows a dependence on the phase of the field at which the excitation occurs. This phase dependence is comparable to that seen in strong field experiments using attosecond pulses to probe systems perturbed by intense infrared (IR) fields. In zero average field, final energies exhibit a phase dependence at twice the frequency of the MW field. We show a phase dependence at the same frequency as the MW field emerges in the presence of a non-zero average field, parallel to the MW polarization. To isolate phase dependence at the MW frequency, we amplitude modulate the IR excitation laser and phase lock this modulation to the MW field. Li atoms are excited to states near the ionization limit in the presence of a MW field, and bound Rydberg states (n>150) are detected. In an applied average field, we observe modulation of the Rydberg signal at the MW frequency. This modulation vanishes as the average field is zeroed, but persists even in fields large enough to ionize most of the population. We compare these results to symmetry arguments and a model of classical Rydberg orbits. An experiment to determine the absolute phase of the modulation relative the MW field is discussed. This work is supported by the US Department of Energy.

  9. Nonlinear optical susceptibility of EIT systems with a degenerate Rydberg level

    NASA Astrophysics Data System (ADS)

    Stanojevic, Jovica; Grangier, Philippe; Côté, Robin

    2016-06-01

    It has been demonstrated that very large optical nonlinearities can arise in cold Rydberg gases from strong Rydberg–Rydberg interactions. The interactions between atoms excited to a degenerate Rydberg level are described by a large number of molecular potentials which greatly complicates the theoretical treatment of these systems. We here present a method for very accurate calculation of the third order interaction-induced optical nonlinearities that fully includes the angle-dependent mixing of molecular states by the control optical field. In addition, we investigate how an effective potential can be introduced to describe the third-order optical susceptibility arising from the underlying multi-potential Rydberg–Rydberg interactions. We show that a single effective potential can replace a manifold of asymptotically degenerate potentials of the same sign. Therefore, one effective potential has to be defined for attractive interactions and another for repulsive ones. As an example, we have calculated effective C 6 coefficients of nd + nd asymptotes of rubidium and cesium. We compare accurately calculated collisional integrals with those obtained using effective potentials.

  10. Probing an Electron Scattering Resonance using Rydberg Molecules within a Dense and Ultracold Gas

    NASA Astrophysics Data System (ADS)

    Schlagmüller, Michael; Liebisch, Tara Cubel; Nguyen, Huan; Lochead, Graham; Engel, Felix; Böttcher, Fabian; Westphal, Karl M.; Kleinbach, Kathrin S.; Löw, Robert; Hofferberth, Sebastian; Pfau, Tilman; Pérez-Ríos, Jesús; Greene, Chris H.

    2016-02-01

    We present spectroscopy of a single Rydberg atom excited within a Bose-Einstein condensate. We not only observe the density shift as discovered by Amaldi and Segrè in 1934, but a line shape that changes with the principal quantum number n . The line broadening depends precisely on the interaction potential energy curves of the Rydberg electron with the neutral atom perturbers. In particular, we show the relevance of the triplet p -wave shape resonance in the e--Rb (5 S ) scattering, which significantly modifies the interaction potential. With a peak density of 5.5 ×1014 cm-3 , and therefore an interparticle spacing of 1300 a0 within a Bose-Einstein condensate, the potential energy curves can be probed at these Rydberg ion-neutral atom separations. We present a simple microscopic model for the spectroscopic line shape by treating the atoms overlapped with the Rydberg orbit as zero-velocity, uncorrelated, pointlike particles, with binding energies associated with their ion-neutral separation, and good agreement is found.

  11. Density matrix reconstruction of three-level atoms via Rydberg electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Gavryusev, V.; Signoles, A.; Ferreira-Cao, M.; Zürn, G.; Hofmann, C. S.; Günter, G.; Schempp, H.; Robert-de-Saint-Vincent, M.; Whitlock, S.; Weidemüller, M.

    2016-08-01

    We present combined measurements of the spatially resolved optical spectrum and the total excited-atom number in an ultracold gas of three-level atoms under electromagnetically induced transparency conditions involving high-lying Rydberg states. The observed optical transmission of a weak probe laser at the center of the coupling region exhibits a double peaked spectrum as a function of detuning, while the Rydberg atom number shows a comparatively narrow single resonance. By imaging the transmitted light onto a charge-coupled-device camera, we record hundreds of spectra in parallel, which are used to map out the spatial profile of Rabi frequencies of the coupling laser. Using all the information available we can reconstruct the full one-body density matrix of the three-level system, which provides the optical susceptibility and the Rydberg density as a function of spatial position. These results help elucidate the connection between three-level interference phenomena, including the interplay of matter and light degrees of freedom and will facilitate new studies of many-body effects in optically driven Rydberg gases.

  12. Probing an Electron Scattering Resonance using Rydberg Molecules within a Dense and Ultracold Gas.

    PubMed

    Schlagmüller, Michael; Liebisch, Tara Cubel; Nguyen, Huan; Lochead, Graham; Engel, Felix; Böttcher, Fabian; Westphal, Karl M; Kleinbach, Kathrin S; Löw, Robert; Hofferberth, Sebastian; Pfau, Tilman; Pérez-Ríos, Jesús; Greene, Chris H

    2016-02-01

    We present spectroscopy of a single Rydberg atom excited within a Bose-Einstein condensate. We not only observe the density shift as discovered by Amaldi and Segrè in 1934, but a line shape that changes with the principal quantum number n. The line broadening depends precisely on the interaction potential energy curves of the Rydberg electron with the neutral atom perturbers. In particular, we show the relevance of the triplet p-wave shape resonance in the e^{-}-Rb(5S) scattering, which significantly modifies the interaction potential. With a peak density of 5.5×10^{14}  cm^{-3}, and therefore an interparticle spacing of 1300 a_{0} within a Bose-Einstein condensate, the potential energy curves can be probed at these Rydberg ion-neutral atom separations. We present a simple microscopic model for the spectroscopic line shape by treating the atoms overlapped with the Rydberg orbit as zero-velocity, uncorrelated, pointlike particles, with binding energies associated with their ion-neutral separation, and good agreement is found. PMID:26894707

  13. Photoionization indicators of optical mixing of different-parity degenerate Rydberg states

    NASA Astrophysics Data System (ADS)

    Parzyński, R.; Sobczak, M.; Wójcik, A.

    2000-02-01

    We discuss a photoionization version of the photoexcitation model of Corless and Stroud [Phys. Rev. Lett. 79, 637 (1997)]. In the photoexcitation model, a np hydrogenic state of n>>1 was excited from the ground 1s state and the excited population was allowed to migrate to other angular momentum states within the one n only due to strongly nonresonant electric-dipole \\|Δn\\|=0, \\|Δl\\|=1 Rydberg-to-Rydberg couplings. When, as is the essence of the photoexcitation model, the same one n-manifold approximation is made in the model of high-n Rydberg-state photoionization, a number of interesting photoionization effects are obtained. Among them, the most spectacular seems to be the emission of photoelectrons in the ``forbidden'' directions and the suppression of ionization when compared to the Fermi golden rule predictions. However, we show on the basis of an approximate analysis that these photoionization effects can be strongly diminished when additional n manifolds around the selected one are included in the model. Thus, we conclude that the one n-manifold approximation overestimates results when applied to the problem of high-n Rydberg-state photoionization.

  14. Population transfer collisions involving nD Rydberg atoms in a CO2 optical dipole trap

    NASA Astrophysics Data System (ADS)

    Kondo, Jorge M.; Goncalves, Luis F.; Tallant, Jonathan E.; Marcassa, Luis G.

    2014-05-01

    There has been an increasing interest in cold Rydberg atoms over the last several years. The primary reason for this attention is that interactions between Rydberg atoms are strong and lead to many interesting and useful phenomena, which require high atomic density samples. In this work, we have loaded Rb atoms into a CO2 optical dipole trap. After the loading, we turn off the dipole trap and excite the Rydberg state using a combination of two cw laser beams at 780 nm and 480 nm respectively. Finally, the Rydberg atoms are detected using pulsed field ionization technique. By analyzing the electrons signal, we can study the population transfer from the nD state to the (n + 2)P as a function of the atomic density for 37 <= n <= 45. As the atomic density increases, the excitation of the nD state saturates, suggesting the occurrence of dipole blockade. Nevertheless, the (n + 2)P is quadratically proportional to the nD population. We have also investigated the role of a dc electrical field in such process. This work was supported by Fapesp and INCT-IQ.

  15. Multiphoton Ionization Dynamics of Strontium Rydberg States in Intense Femtosecond Pulses

    NASA Astrophysics Data System (ADS)

    Tate, D. A.; Gallagher, T. F.

    1997-04-01

    We are investigating multiphoton ionization of Sr 5snl Rydberg states by intense 150 fs pulses. Specifically, we excite the 5snd 20 < n < ∞ states using two ns lasers at 460.9 nm and 420 - 412 nm. These states are then irradiated with the fs pulses which are produced by a mode-locked, regeneratively amplified Ti:Sapphire laser. The laser is tunable between 790 nm and 844 nm, and the pulses are frequency doubled to produce light from 395 - 422 nm. In contrast with a previous experiment, which used ps laser pulses,(H. Stapelfeldt, D.G. Papaioannou, L.D. Noordam, and T.F. Gallagher, Phys. Rev. A, 67, 3223 (1991).) our preliminary results indicate that excitation of Sr^+ Rydberg states and Sr^2+ photoions is relatively insensitive to the fs laser wavelength. We detect both species when the fs pulses are tuned to the 5s arrow 8p (398 nm) and 5s arrow 5f (422 nm) three photon resonances in Sr^+. In addition, we have generated Sr^+ Rydberg states and Sr^2+ using the laser fundamental at 796 nm, though when the laser is tuned to 844nm, the Sr^+ Rydberg states are no longer excited. We will present a systematic experimental study of the ionization process and discuss our results in terms of Floquet theory.

  16. High-order-harmonic generation from Rydberg atoms driven by plasmon-enhanced laser fields

    NASA Astrophysics Data System (ADS)

    Tikman, Y.; Yavuz, I.; Ciappina, M. F.; Chacón, A.; Altun, Z.; Lewenstein, M.

    2016-02-01

    We theoretically investigate high-order-harmonic generation (HHG) in Rydberg atoms driven by spatially inhomogeneous laser fields, induced, for instance, by plasmonic enhancement. It is well known that the laser intensity should exceed a certain threshold in order to stimulate HHG when noble gas atoms in their ground state are used as an active medium. One way to enhance the coherent light coming from a conventional laser oscillator is to take advantage of the amplification obtained by the so-called surface plasmon polaritons, created when a low-intensity laser field is focused onto a metallic nanostructure. The main limitation of this scheme is the low damage threshold of the materials employed in the nanostructure engineering. In this work we propose the use of Rydberg atoms, driven by spatially inhomogeneous, plasmon-enhanced laser fields, for HHG. We exhaustively discuss the behavior and efficiency of these systems in the generation of coherent harmonic emission. Toward this aim we numerically solve the time-dependent Schrödinger equation for an atom, with an electron initially in a highly excited n th Rydberg state, located in the vicinity of a metallic nanostructure. In this zone the electric field changes spatially on scales relevant for the dynamics of the laser-ionized electron. We first use a one-dimensional model to investigate systematically the phenomena. We then employ a more realistic situation, in which the interaction of a plasmon-enhanced laser field with a three-dimensional hydrogen atom is modeled. We discuss the scaling of the relevant input parameters with the principal quantum number n of the Rydberg state in question and demonstrate that harmonic emission can be achieved from Rydberg atoms well below the damage threshold, thus without deterioration of the geometry and properties of the metallic nanostructure.

  17. Dipole-dipole resonance line shapes in a cold Rydberg gas

    NASA Astrophysics Data System (ADS)

    Richards, B. G.; Jones, R. R.

    2016-04-01

    We have explored the dipole-dipole mediated, resonant energy transfer reaction, 32 p3 /2+32 p3 /2→32 s +33 s , in an ensemble of cold 85Rb Rydberg atoms. Stark tuning is employed to measure the population transfer probability as a function of the total electronic energy difference between the initial and final atom-pair states over a range of Rydberg densities, 2 ×108≤ρ ≤3 ×109 cm-3. The observed line shapes provide information on the role of beyond nearest-neighbor interactions, the range of Rydberg atom separations, and the electric field inhomogeneity in the sample. The widths of the resonance line shapes increase approximately linearly with the Rydberg density and are only a factor of 2 larger than expected for two-body, nearest-neighbor interactions alone. These results are in agreement with the prediction [B. Sun and F. Robicheaux, Phys. Rev. A 78, 040701(R) (2008), 10.1103/PhysRevA.78.040701] that beyond nearest-neighbor exchange interactions should not influence the population transfer process to the degree once thought. At low densities, Gaussian rather than Lorentzian line shapes are observed due to electric field inhomogeneities, allowing us to set an upper limit for the field variation across the Rydberg sample. At higher densities, non-Lorentzian, cusplike line shapes characterized by sharp central peaks and broad wings reflect the random distribution of interatomic distances within the magneto-optical trap (MOT). These line shapes are well reproduced by an analytic expression derived from a nearest-neighbor interaction model and may serve as a useful fingerprint for characterizing the position correlation function for atoms within the MOT.

  18. Using frequency detuning to improve the sensitivity of electric field measurements via electromagnetically induced transparency and Autler-Townes splitting in Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Simons, Matt T.; Gordon, Joshua A.; Holloway, Christopher L.; Anderson, David A.; Miller, Stephanie A.; Raithel, Georg

    2016-04-01

    In this work, we demonstrate an approach for improved sensitivity in weak radio frequency (RF) electric-field strength measurements using Rydberg electromagnetically induced transparency (EIT) in an atomic vapor. This is accomplished by varying the RF frequency around a resonant atomic transition and extrapolating the weak on-resonant field strength from the resulting off-resonant Autler-Townes (AT) splittings. This measurement remains directly traceable to SI compared to previous techniques, precluding any knowledge of experimental parameters such as optical beam powers as is the case when using the curvature of the EIT line shape to measure weak fields. We use this approach to measure weak RF fields at 182 GHz and 208 GHz demonstrating improvement greater than a factor of 2 in the measurement sensitivity compared to on-resonant AT splitting RF electric field measurements.

  19. High-resolution spectroscopy of He2+ using Rydberg-series extrapolation and Zeeman-decelerated supersonic beams of metastable He2

    NASA Astrophysics Data System (ADS)

    Jansen, Paul; Semeria, Luca; Merkt, Frédéric

    2016-04-01

    Recently, high-resolution spectroscopy of slow beams of metastable helium molecules (He2∗) generated by multistage Zeeman deceleration was used in combination with Rydberg-series extrapolation techniques to obtain the lowest rotational interval in the molecular helium ion at a precision of 18 MHz (Jansen et al., 2015), limited by the temporal width of the Fourier-transform-limited laser pulses used to record the spectra. We present here an extension of these measurements in which we have (1) measured higher rotational intervals of He2+, (2) replaced the pulsed UV laser by a cw UV laser and improved the resolution of the spectra by a factor of more than five, and (3) studied MJ redistribution processes in regions of low magnetic fields of the Zeeman decelerator and shown how these processes can be exploited to assign transitions originating from specific spin-rotational levels (N″,J″) of He2∗ .

  20. First-principles investigation on Rydberg and resonance excitations: A case study of the firefly luciferin anion

    NASA Astrophysics Data System (ADS)

    Noguchi, Yoshifumi; Hiyama, Miyabi; Akiyama, Hidefumi; Koga, Nobuaki

    2014-07-01

    The optical properties of an isolated firefly luciferin anion are investigated by using first-principles calculations, employing the many-body perturbation theory to take into account the excitonic effect. The calculated photoabsorption spectra are compared with the results obtained using the time-dependent density functional theory (TDDFT) employing the localized atomic orbital (AO) basis sets and a recent experiment in vacuum. The present method well reproduces the line shape at the photon energy corresponding to the Rydberg and resonance excitations but overestimates the peak positions by about 0.5 eV. However, the TDDFT-calculated positions of some peaks are closer to those of the experiment. We also investigate the basis set dependency in describing the free electron states above vacuum level and the excitons involving the transitions to the free electron states and conclude that AO-only basis sets are inaccurate for free electron states and the use of a plane wave basis set is required.

  1. First-principles investigation on Rydberg and resonance excitations: A case study of the firefly luciferin anion

    SciTech Connect

    Noguchi, Yoshifumi Hiyama, Miyabi; Akiyama, Hidefumi; Koga, Nobuaki

    2014-07-28

    The optical properties of an isolated firefly luciferin anion are investigated by using first-principles calculations, employing the many-body perturbation theory to take into account the excitonic effect. The calculated photoabsorption spectra are compared with the results obtained using the time-dependent density functional theory (TDDFT) employing the localized atomic orbital (AO) basis sets and a recent experiment in vacuum. The present method well reproduces the line shape at the photon energy corresponding to the Rydberg and resonance excitations but overestimates the peak positions by about 0.5 eV. However, the TDDFT-calculated positions of some peaks are closer to those of the experiment. We also investigate the basis set dependency in describing the free electron states above vacuum level and the excitons involving the transitions to the free electron states and conclude that AO-only basis sets are inaccurate for free electron states and the use of a plane wave basis set is required.

  2. Rydberg and valence state excitation dynamics: a velocity map imaging study involving the E-V state interaction in HBr.

    PubMed

    Zaouris, Dimitris; Kartakoullis, Andreas; Glodic, Pavle; Samartzis, Peter C; Rafn Hróðmarsson, Helgi; Kvaran, Ágúst

    2015-04-28

    Photoexcitation dynamics of the E((1)Σ(+)) (v' = 0) Rydberg state and the V((1)Σ(+)) (v') ion-pair vibrational states of HBr are investigated by velocity map imaging (VMI). H(+) photoions, produced through a number of vibrational and rotational levels of the two states were imaged and kinetic energy release (KER) and angular distributions were extracted from the data. In agreement with previous work, we found the photodissociation channels forming H*(n = 2) + Br((2)P3/2)/Br*((2)P1/2) to be dominant. Autoionization pathways leading to H(+) + Br((2)P3/2)/Br*((2)P1/2) via either HBr(+)((2)Π3/2) or HBr(+)*((2)Π1/2) formation were also present. The analysis of KER and angular distributions and comparison with rotationally and mass resolved resonance enhanced multiphoton ionization (REMPI) spectra revealed the excitation transition mechanisms and characteristics of states involved as well as the involvement of the E-V state interactions and their v' and J' dependence. PMID:25801122

  3. Quantum defects of nonpenetrating Rydberg states of the SO molecule in adiabatic and nonadiabatic regions of the spectrum

    NASA Astrophysics Data System (ADS)

    Dorofeev, Dmitry L.; Elfimov, Sergei V.; Zon, Boris A.

    2012-02-01

    This paper is dedicated to the implementation of a generalized approach for calculating quantum defects in high Rydberg states of polar molecules with an account for the dipole moment of the molecular core and l uncoupling of the Rydberg electron. Adiabatic (Born-Oppenheimer) and nonadiabatic (inverse Born-Oppenheimer) regions of the spectrum are considered. The nonadiabatic case with a nonzero projection of the core momentum on the core axis is considered and is illustrated by the example of the SO molecule.

  4. Observation of Rydberg blockade effects at very high n, n ~ 300 , using strontium n1F3 states

    NASA Astrophysics Data System (ADS)

    Zhang, Xinyue; Dunning, F. B.; Yoshida, Shuhei; Burgdörfer, Joachim

    2015-05-01

    Rydberg blockade at very high n, n ~ 300 , is examined using strontium n1F3 Rydberg atoms excited in a small volume defined by two tightly-focused crossed laser beams. Measurements of the number distribution of Rydberg atoms created show deviations from a Poisson distribution revealing sizeable blockade effects. The statistics of the number distribution are studied using a Monte Carlo method in which the interaction between strontium Rydberg atoms is evaluated by solving the Schrödinger equation within a two-active-electron model. The strength of blockade is analyzed in detail with respect to the alignment of two atoms relative to the laser polarizations. With careful control of the experimental parameters the probability for creating one, and only one, Rydberg atom, P(1) , in the excitation volume can be sufficiently large, P(1) > 0 . 6 , as to enable detailed studies of strongly-coupled Rydberg atom pairs. Research supported by the NSF, the Robert A. Welch Foundation, and the FWF (Austria).

  5. Heavy Rydberg behaviour in high vibrational levels of some ion-pair states of the halogens and inter-halogens

    SciTech Connect

    Donovan, Robert J. E-mail: tr01@staffmail.ed.ac.uk; Lawley, Kenneth P. Ridley, Trevor E-mail: tr01@staffmail.ed.ac.uk

    2015-05-28

    We report the identification of heavy Rydberg resonances in the ion-pair spectra of I{sub 2}, Cl{sub 2}, ICl, and IBr. Extensive vibrational progressions are analysed in terms of the energy dependence of the quantum defect δ(E{sub b}) rather than as Dunham expansions. This is shown to define the heavy Rydberg region, providing a more revealing fit to the data with fewer coefficients and leads just as easily to numbering data sets separated by gaps in the observed vibrational progressions. Interaction of heavy Rydberg states with electronic Rydberg states at avoided crossings on the inner wall of the ion-pair potential is shown to produce distinctive changes in the energy dependence of δ(E{sub b}), with weak and strong interactions readily distinguished. Heavy Rydberg behaviour is found to extend well below near-dissociation states, down to vibrational levels ∼18 000-20 000 cm{sup −1} below dissociation. The rapid semi-classical calculation of δ(E{sub b}) for heavy Rydberg states is emphasised and shows their absolute magnitude to be essentially the volume of phase space excluded from the vibrational motion by avoiding core-core penetration of the ions.

  6. Characterization of Launched Atoms Leading to Observations of Cold Rydberg Atoms in the Field of a Charged Wire

    NASA Astrophysics Data System (ADS)

    Goodsell, Anne; Erwin, Emma

    2016-05-01

    We are preparing to accelerate and decelerate cold Rydberg atoms in the field of a charged wire. We cool and launch rubidium atoms and observe the distribution of atoms up to 16 mm above the trap location. We report a transverse speed less than 1/10 of the longitudinal launch speed. For Rydberg-atom observations, the cold cloud will be illuminated in mid-flight to promote atoms into the desired Rydberg state (e.g. n = 33-40). With a three-photon sequence we will access nf states and the nearby manifolds with linear Stark shifts. We observed the first two steps of this process using counter-propagating beams of 780 nm and 776 nm in a Rb cell. For cold Rydberg atoms, we will compare states that are strongly accelerated to states that are strongly decelerated by the field around the charged-wire target. We calculate that the displacement during the Rydberg lifetime (e.g. n = 35, τ = 30 μs) will be 200-300 μm farther for extreme attracted states. Detection will occur by spatially-dependent field ionization. Observations of atoms with zero angular momentum around the wire can be extended to atoms with nonzero angular momentum and also to study dynamics of Rydberg atoms with a quadratic Stark shift, building on previous work with ground-state atoms.

  7. Long-lived Electronic Coherence of Rydberg States in the Strong-Field Ionization of a Polyatomic Molecule

    NASA Astrophysics Data System (ADS)

    Konar, Arkaprabha; Shu, Yinan; Levine, Benjamin; Lozovoy, Vadim; Dantus, Marcos

    2015-05-01

    Here, we report on quantum coherent control of a large (>20 atoms) polyatomic molecule. In particular, we explore the time resolved dynamics of dicyclopentadiene when excited by a pair of phase-locked intense 800nm femtosecond pulses by monitoring changes in ion yield of the parent and fragments. Long-lived oscillations are observed for ~ 500 fs in the parent ion yield indicating the presence of long lived-electronic states. We take advantage of the long-lived electronic coherence to control the yield of different fragment ions. The presence of Rydberg states is further supported by ab initio calculations at the EOM-CCSD/6-31 +G** level of theory which identified five low-lying electronic states of neutral DCPD in the regions between 6.4 and 7.0 eV in vertical excitation energy. States of both pure Rydberg and mixed π --> π */Rydberg character are observed in this low energy region and are known to originate from ethylene. The multiphoton excitation of two or more Rydberg states, separated by the photon energy is the key to the observed long-lived electronic coherence in DCPD with a quantum beat at the difference frequency. Rydberg states are expected to have very similar potential energy surfaces and the Rydberg electron is relatively uncoupled to the nuclear dynamics, therefore supporting long electronic coherence time.

  8. Predissociation of high-lying Rydberg states of molecular iodine via ion-pair states

    SciTech Connect

    Bogomolov, Alexandr S.; Grüner, Barbara; Mudrich, Marcel; Kochubei, Sergei A.; Baklanov, Alexey V.

    2014-03-28

    Velocity map imaging of the photofragments arising from two-photon photoexcitation of molecular iodine in the energy range 73 500–74 500 cm{sup −1} covering the bands of high-lying gerade Rydberg states [{sup 2}Π{sub 1/2}]{sub c}6d;0{sub g}{sup +} and [{sup 2}Π{sub 1/2}]{sub c}6d;2{sub g} has been applied. The ion signal was dominated by the atomic fragment ion I{sup +}. Up to 5 dissociation channels yielding I{sup +} ions with different kinetic energies were observed when the I{sub 2} molecule was excited within discrete peaks of Rydberg states and their satellites in this region. One of these channels gives rise to images of I{sup +} and I{sup −} ions with equal kinetic energy indicating predissociation of I{sub 2} via ion-pair states. The contribution of this channel was up to about 50% of the total I{sup +} signal. The four other channels correspond to predissociation via lower lying Rydberg states giving rise to excited iodine atoms providing I{sup +} ions by subsequent one-photon ionization by the same laser pulse. The ratio of these channels varied from peak to peak in the spectrum but their total ionic signal was always much higher than the signal of (2 + 1) resonance enhanced multi-photon ionization of I{sub 2}, which was previously considered to be the origin of ionic signal in this spectral range. The first-tier E0{sub g}{sup +} and D{sup ′}2{sub g} ion-pair states are concluded to be responsible for predissociation of Rydberg states [{sup 2}Π{sub 1/2}]{sub c}6d;0{sub g}{sup +} and [{sup 2}Π{sub 1/2}]{sub c}6d;2{sub g}, respectively. Further predissociation of these ion-pair states via lower lying Rydberg states gives rise to excited I(5s{sup 2}5p{sup 4}6s{sup 1}) atoms responsible for major part of ion signal. The isotropic angular distribution of the photofragment recoil directions observed for all channels indicates that the studied Rydberg states are long-lived compared with the rotational period of the I{sub 2} molecule.

  9. Rydberg transitions for positron-hydrogen collisions: asymptotic cross section and scaling law

    NASA Astrophysics Data System (ADS)

    Rej, Pramit; Ghoshal, Arijit

    2014-01-01

    The dynamics of 1s → nlm excitations of hydrogen, for arbitrary n, l, m, by positron impact has been investigated using a distorted-wave theory in the momentum space. It has been possible to obtain the distorted-wave scattering amplitude in a closed analytical form. A detailed study has been made on the differential and total cross sections in the energy range 20-300 eV of incident positron. A simple law has been presented for obtaining asymptotic cross sections for excitation into different angular momentum states. To the best of our knowledge, such a study on the differential and total cross sections for 1s → nlm inelastic positron-hydrogen collisions using distorted-wave theory is the first reported in the literature.

  10. Towards a controlled-phase gate using Rydberg-dressed atoms

    NASA Astrophysics Data System (ADS)

    Hankin, Aaron; Jau, Yuan-Yu; Biedermann, Grant

    2014-05-01

    We are implementing a controlled-phase gate based on singly trapped neutral atoms whose coupling is mediated by the dipole-dipole interaction of Rydberg states. An off-resonant laser field dresses ground state cesium atoms in a manner conditional on the Rydberg blockade mechanism, providing the required entangling interaction. We will present our progress toward implementing the controlled-phase gate with an analysis of possible sources of decoherence such as RF radiation from wireless communication devices. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  11. Simulations of the angular dependence of the dipole-dipole interaction among Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Bigelow, Jacob L.; Hollingsworth, Jacob; Paul, Jacob T.; Peleg, Matan; Sanford, Veronica L.; Carroll, Thomas J.; Noel, Michael W.

    2016-05-01

    The dipole-dipole interaction between two Rydberg atoms depends on the relative orientation of the atoms and on the change in the magnetic quantum number. We simulate the effect of this anisotropy on the energy transport in an amorphous many atom system of ultracold Rydberg atoms subject to a homogeneous applied electric field. We consider two experimentally feasible geometries and find that the effects should be measurable in current generation imaging experiments. We also examine evidence for Anderson localization. This work was supported by the National Science Foundation under Grants No. 1205895 and No. 1205897 and used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant Number OCI-1053575.

  12. Exotic topological density waves in cold atomic Rydberg-dressed fermions

    PubMed Central

    Li, Xiaopeng; Sarma, S Das

    2015-01-01

    Versatile controllability of interactions in ultracold atomic and molecular gases has now reached an era where quantum correlations and unconventional many-body phases can be studied with no corresponding analogues in solid-state systems. Recent experiments in Rydberg atomic gases have achieved exquisite control over non-local interactions, allowing novel quantum phases unreachable with the usual local interactions in atomic systems. Here we study Rydberg-dressed atomic fermions in a three-dimensional optical lattice predicting the existence of hitherto unheard-of exotic mixed topological density wave phases. By varying the spatial range of the non-local interaction, we find various chiral density waves with spontaneous time-reversal symmetry breaking, whose quasiparticles form three-dimensional quantum Hall and Weyl semimetal states. Remarkably, certain density waves even exhibit mixed topologies beyond the existing topological classification. Our results suggest gapless fermionic states could exhibit far richer topology than previously expected. PMID:25972134

  13. Quasiforbidden two-body Förster resonances in a cold Cs Rydberg gas

    NASA Astrophysics Data System (ADS)

    Pelle, B.; Faoro, R.; Billy, J.; Arimondo, E.; Pillet, P.; Cheinet, P.

    2016-02-01

    Cold Rydberg atoms are known to display dipole-dipole interaction-allowed resonances, also called Förster resonances, which lead to an efficient energy transfer when the proper electric field is used. This electric field also enables resonances, which do not respect the dipole-dipole selection rules under zero field. A few of these quasiforbidden resonances have been observed but they are often overlooked. Here we show that in cold 133Cs atoms there is a large number of these resonances that display a significant transfer efficiency due to their strong interactions, even at low electric field. We also develop a graphical method enabling us to find all possible resonances simultaneously. The resulting dramatic increase in the total number of addressable resonant energy transfers at different electric fields could have implications in the search for few-body interactions or macromolecules built from Rydberg atoms.

  14. Duality and bistability in an optomechanical cavity coupled to a Rydberg superatom

    NASA Astrophysics Data System (ADS)

    Yan, Dong; Wang, Zhi-Hai; Ren, Chun-Nian; Gao, Hang; Li, Yong; Wu, Jin-Hui

    2015-02-01

    We study the steady-state behaviors of a typical optomechanical cavity coupled to cold Rydberg atoms with dipole-dipole interactions. The interacting atoms are described as one superatom of three collective states in a ladder configuration in the limit of a strong dipole blockade and a weak cavity field. We find that this hybrid system exhibits phenomena of conditional duality and nonlinear bistability in terms of mirror displacement, number of cavity photons, and Rydberg population, depending on the detuning of the cavity field, the strength of the optical driving field, and the number of cold atoms. It is of particular interest that the two branches of relevant curves may intersect to yield a nontrivial duality and bistability. Such correlated optical, mechanical, and atomic responses arise from the efficient feedback between atom-light and optomechanical interactions and have realistic applications, e.g., in realizing accurate optomechanical detection or attaining deterministic single photons.

  15. Demonstration of Turnstiles as a Chaotic Ionization Mechanism in Rydberg Atoms

    SciTech Connect

    Burke, Korana; Mitchell, Kevin A.; Wyker, Brendan; Ye Shuzhen; Dunning, F. Barry

    2011-09-09

    We present an experimental and theoretical study of the chaotic ionization of quasi-one-dimensional potassium Rydberg wave packets via a classical phase-space turnstile mechanism. Turnstiles form a general transport mechanism for numerous chaotic systems, and this study explicitly illuminates their relevance to atomic ionization. We create time-dependent Rydberg wave packets, subject them to alternating applied electric-field pulses, and measure the electron survival probability. Ionization depends not only on the initial electron energy, but also on the classical phase-space position of the electron with respect to the turnstile--that part of the electron packet inside the turnstile ionizes after the applied ionization sequence, while that part outside the turnstile does not. The survival data thus encode information on the shape and location of the turnstile, in good agreement with theoretical predictions.

  16. Formation of positron-atom bound states in collisions between Rydberg Ps and neutral atoms

    NASA Astrophysics Data System (ADS)

    Swann, A. R.; Cassidy, D. B.; Deller, A.; Gribakin, G. F.

    2016-05-01

    Predicted 20 years ago, positron binding to neutral atoms has not yet been observed experimentally. A scheme is proposed to detect positron-atom bound states by colliding Rydberg positronium (Ps) with neutral atoms. Estimates of the charge-transfer reaction cross section are obtained using the first Born approximation for a selection of neutral atom targets and a wide range of incident Ps energies and principal quantum numbers. We also estimate the corresponding Ps ionization cross section. The accuracy of the calculations is tested by comparison with earlier predictions for charge transfer in Ps collisions with hydrogen and antihydrogen. We describe an existing Rydberg Ps beam suitable for producing positron-atom bound states and estimate signal rates based on the calculated cross sections and realistic experimental parameters. We conclude that the proposed methodology is capable of producing such states and of testing theoretical predictions of their binding energies.

  17. Studying dissociative electron attachment through formation of heavy-Rydberg ion-pair states

    NASA Astrophysics Data System (ADS)

    Kelley, Michael; Buathong, Sitti; Dunning, F. Barry

    2016-05-01

    Following dissociative electron transfer in collisions between Rydberg atoms and electron-attaching targets, it is possible for the resulting pair of ions to remain electrostatically bound, forming heavy-Rydberg ion-pair states. Precise measurement of the velocity distributions of such ion-pair states provides information concerning the dissociation dynamics of the excited intermediates initially created by electron transfer. Here, electric-field-induced dissociation is used to detect the product ion pairs and observe their velocity distributions. These distributions are analyzed with the aid of a Monte Carlo collision code that models the electron transfer. Measurements with a number of different target species show that through this analysis, dissociation energetics, the branching ratios into different dissociation products, and the lifetimes of the excited intermediates can be examined. Research supported by the Robert A. Welch Foundation.

  18. Superfluid Pairing and Majorana Zero Mode in an Ultracold Rydberg Fermi Gas

    NASA Astrophysics Data System (ADS)

    Xiong, Bo; Jen, H. H.; You, Jhih-Shih; Wang, Daw-Wei

    2013-03-01

    We systematically calculate the p-wave superfluid phase of spin polarized Fermi gases in a Rydberg state. The mutual interaction between atoms are dressed by external fields and show nonlocal attractive 1/(a +r6) interaction. Different from the p-wave pairing phase of regular atoms near p-wave Feshbach resonance, the obtained p-wave superfluid phase can be stable away from three-body collision and has intrinsic nontrivial nodes in the momentum space. The critical temperature and order parameter for various interaction parameters have been calculated analytically and numerically, both in the 2D and 3D free space. When loading into optical lattice, we also show the proximity effect of Tc near half filling. Finally, when considering the harmonic confinement potential, we obtain the gapless Majorana Fermions confined to the boundary via self-consistently solving the DBG equation. We will discuss how to experimentally prepare and measure these Majorana states in Rydberg atoms.

  19. Control of Diabatic versus Adiabatic Field Dissociation in a Heavy Rydberg System

    SciTech Connect

    Shiell, R.C.; Reinhold, E.; Ubachs, W.; Magnus, F.

    2005-11-18

    A novel phenomenon is observed in the dynamics of laser-prepared coherent wave packets, bound by the Coulombic 1/r potential of an ion-pair system. After exciting weakly bound ({approx_equal}3 meV) H{sup +}F{sup -} wave packets in a Stark field, and permitting them to evolve in time, control of field dissociation via adiabatic and diabatic routes is demonstrated by applying delayed pulsed-electric fields, involving a zero-field crossing. Control manifests itself through the production of ions from each pathway at a different instant in time. This phenomenon is applied to map the oscillatory behavior of an angular momentum wave packet in a heavy Rydberg system. The characteristic frequencies of the observed Stark oscillations verify predicted mass-scaling laws for heavy Rydberg systems.

  20. Production of trilobite Rydberg molecule dimers with kilo-Debye permanent electric dipole moments

    NASA Astrophysics Data System (ADS)

    Booth, D.; Rittenhouse, S. T.; Yang, J.; Sadeghpour, H. R.; Shaffer, J. P.

    2015-04-01

    Permanent electric dipole moments are important for understanding symmetry breaking in molecular physics, control of chemical reactions, and realization of strongly correlated many-body quantum systems. However, large molecular permanent electric dipole moments are challenging to realize experimentally. We report the observation of ultralong-range Rydberg molecules with bond lengths of ~100 nanometers and kilo-Debye permanent electric dipole moments that form when an ultracold ground-state cesium (Cs) atom becomes bound within the electronic cloud of an extended Cs electronic orbit. The electronic character of this hybrid class of “trilobite” molecules is dominated by degenerate Rydberg manifolds, making them difficult to produce by conventional photoassociation. We used detailed coupled-channel calculations to reproduce their properties quantitatively. Our findings may lead to progress in ultracold chemistry and strongly correlated many-body physics.

  1. Imaging electric fields in the vicinity of cryogenic surfaces using Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Thiele, T.; Deiglmayr, J.; Stammeier, M.; Agner, J.-A.; Schmutz, H.; Merkt, F.; Wallraff, A.

    2015-12-01

    The ability to characterize static and time-dependent electric fields in situ is an important prerequisite for quantum-optics experiments with atoms close to surfaces. Especially in experiments which aim at coupling Rydberg atoms to the near field of superconducting circuits, the identification and subsequent elimination of sources of stray fields are crucial. We present a technique that allows the determination of stray-electric-field distributions [Fxstr(r ⃗) ,Fystr(r ⃗) ,Fzstr(r ⃗) ] at distances of less than 2 mm from (cryogenic) surfaces using coherent Rydberg-Stark spectroscopy in a pulsed supersonic beam of metastable 1 s12 s11S0 helium atoms. We demonstrate the capabilities of this technique by characterizing the electric stray field emanating from a structured superconducting surface. Exploiting coherent population transfer with microwave radiation from a coplanar waveguide, the same technique allows the characterization of the microwave-field distribution above the surface.

  2. Motion of Rydberg atoms with strong permanent-electric-dipole interactions

    NASA Astrophysics Data System (ADS)

    Gonçalves, Luís Felipe; Thaicharoen, Nithiwadee; Raithel, Georg

    2016-08-01

    Using classical trajectories simulations, we investigate the dynamics of a cold sample of Rydberg atoms with high permanent electric dipole moments. The dipolar state can be created using an adiabatic passage through an avoided crossing between an S-like state and a linear Stark state. The simulations yield the pair-correlation functions (PCF) of the atom samples, which allow us to extract the motion of Rydberg-atom pairs in the many-body system. The results reveal the strength and the anisotropic character of the underlying interaction. The simulation is employed to test the suitability of experimental methods designed to derive interaction parameters from PCF. Insight is obtained about the stability of the method against variation of experimentally relevant parameters. Transient correlations due to interaction-induced heating are observed.

  3. MPI spectroscopy in the region of the 3p Rydberg state of some cycloketones

    NASA Astrophysics Data System (ADS)

    Kosmidis, C.; Boulakis, G.; Bolovinos, A.; Tsekeris, P.; Brint, P.

    1992-03-01

    The two-photon resonance three photon ionization spectra of cyclopentanone, cyclohexanone and cycloheptanone in the region of the 3p Rydberg state have been recorded, analysed and compared with the one-photon absorption spectra. A new 3p origin is identified for cyclopentanone. The absence from the MPI spectra of a sharp spectral feature that is observed in the absorption spectra is discussed. Photochemical generation of acetaldehyde is observed at high laser intensities and possible mechanisms for this are considered.

  4. Grover search algorithm with Rydberg-blockaded atoms: quantum Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Petrosyan, David; Saffman, Mark; Mølmer, Klaus

    2016-05-01

    We consider the Grover search algorithm implementation for a quantum register of size N={2}k using k (or k+1) microwave- and laser-driven Rydberg-blockaded atoms, following the proposal by Mølmer et al (2011 J. Phys. B 44 184016). We suggest some simplifications for the microwave and laser couplings, and analyze the performance of the algorithm for up to k = 4 multilevel atoms under realistic experimental conditions using quantum stochastic (Monte Carlo) wavefunction simulations.

  5. Atomic jet with ionization detection for laser spectroscopy of Rydberg atoms under collisions and fields

    NASA Astrophysics Data System (ADS)

    Philip, G.

    2008-03-01

    An efficient atomic jet setup offering many unprecedented advantages over a conventional heat pipe setup used in multi-photon spectroscopy, mainly of alkaline-earth metals, has been constructed by a scheme in which the sample material is encapsulated in a disposable cartridge oven located inside a thermally stabilised heat-pipe and is made to effuse in to a row of atomic beams merging to form a jet target. This novel scheme combines the advantages of both high density atomic beam with convenient geometry for orthogonal excitation and high sensitive ionisation detection capabilities of thermionic diodes, besides eliminating several problems inherent in the usual heat-pipe operation. Out of various designs, typical results are presented for a linear heat-pipe with vertical atomic jet used in two-photon spectroscopy of highly excited states of Sr I. Controlled excitations of both Rydberg and non-Rydberg states, which cannot otherwise be accessed from the ground state due to parity and spectroscopic selection rules, have been achieved by employing a weak electric field complimented by collisions. The atomic jet setup is also found very useful for the study of collisional broadening and shift of excited states and time evolution of Rydberg atoms.

  6. Solvation effects on the molecular 3s Rydberg state: AZAB/CYCLO octanes clustered with argon

    NASA Astrophysics Data System (ADS)

    Shang, Q. Y.; Moreno, P. O.; Li, S.; Bernstein, E. R.

    1993-02-01

    Two color, 1+1, mass resolved excitation spectroscopy (MRES) is used to obtain molecular Rydberg (3s←n) spectra of azabicyclo[2.2.2]octane (ABCO) and diazabicyclo[2.2.2]octane (DABCO) clustered with argon. Nozzle/laser timing delay studies are employed together with time-of-flight mass spectroscopy to identify cluster composition. Population depletion techniques are used to differentiate between clusters with the same mass, but different geometries. A Lennard-Jones 6-12 potential is used to model the intermolecular interactions and predict minimum energy cluster geometries and cluster binding energies. The experimental results are combined with the cluster geometry calculations to assign spectral features to specific cluster geometries. Three different excited state interactions are required to model the experimentally observed line shapes, spectral shifts, and cluster dissociation. The relationship between these model potentials and the cluster binding sites suggests that the form of the cluster intermolecular potential in the Rydberg excited state is dictated by the distance between the argon and chromophore atoms. A comparison of results for ABCO(Ar)1 and DABCO(Ar)1 leads to the conclusion that the nitrogen 3s Rydberg orbital in clusters of DABCO is delocalized.

  7. Optomechanical Rydberg-atom excitation via dynamic Casimir-Polder coupling.

    PubMed

    Antezza, Mauro; Braggio, Caterina; Carugno, Giovanni; Noto, Antonio; Passante, Roberto; Rizzuto, Lucia; Ruoso, Giuseppe; Spagnolo, Salvatore

    2014-07-11

    We study the optomechanical coupling of a oscillating effective mirror with a Rydberg atomic gas, mediated by the dynamical atom-mirror Casimir-Polder force. This coupling may produce a near-field resonant atomic excitation whose probability scales as ∝(d(2)an(4)t)(2)/z(0)(8), where z(0) is the average atom-surface distance, d the atomic dipole moment, a the mirror's effective oscillation amplitude, n the initial principal quantum number, and t the time. We propose an experimental configuration to realize this system with a cold atom gas trapped at a distance ∼2×10  μm from a semiconductor substrate whose dielectric constant is periodically driven by an external laser pulse, hence realizing an effective mechanical mirror motion due to the periodic change of the substrate from transparent to reflecting. For a parabolic gas shape, this effect is predicted to excite about ∼10(2) atoms of a dilute gas of 10(3) trapped Rydberg atoms with n=75 after about 0.5  μs, which is high enough to be detected in typical Rydberg gas experimental conditions. PMID:25062178

  8. Optomechanical Rydberg-Atom Excitation via Dynamic Casimir-Polder Coupling

    NASA Astrophysics Data System (ADS)

    Antezza, Mauro; Braggio, Caterina; Carugno, Giovanni; Noto, Antonio; Passante, Roberto; Rizzuto, Lucia; Ruoso, Giuseppe; Spagnolo, Salvatore

    2014-07-01

    We study the optomechanical coupling of a oscillating effective mirror with a Rydberg atomic gas, mediated by the dynamical atom-mirror Casimir-Polder force. This coupling may produce a near-field resonant atomic excitation whose probability scales as ∝(d2an4t)2/z08, where z0 is the average atom-surface distance, d the atomic dipole moment, a the mirror's effective oscillation amplitude, n the initial principal quantum number, and t the time. We propose an experimental configuration to realize this system with a cold atom gas trapped at a distance ˜2×10 μm from a semiconductor substrate whose dielectric constant is periodically driven by an external laser pulse, hence realizing an effective mechanical mirror motion due to the periodic change of the substrate from transparent to reflecting. For a parabolic gas shape, this effect is predicted to excite about ˜102 atoms of a dilute gas of 103 trapped Rydberg atoms with n =75 after about 0.5 μs, which is high enough to be detected in typical Rydberg gas experimental conditions.

  9. Classical Monte-Carlo simulation for Rydberg states ionization in strong field

    NASA Astrophysics Data System (ADS)

    Carrat, Vincent; Magnuson, Eric; Gallagher, Thomas

    2016-05-01

    The resilience of Rydberg states against ionization has fascinated physicists for a long time. One might expect that the loosely bound electron would be ionized by modest electromagnetic field. However, experiments show that a notable fraction of neutral atoms survive in Rydberg states when exposed to strong microwave or laser fields. Energy transfer between the field and the photoelectron occurs when the electron is close to the ionic core and depends on the phase of the field. Since those states have orbital times that can be larger than the field pulse duration, these energy exchanges will only occur a few times. While we can experimentally control the initial time when we create the Rydberg states and as a consequence the initial energy transfer from the field, our classical calculation suggests that the phase when the electron is returning to the ionic core on the next orbit is chaotic. Statistically the electron only has a 50% chance to gain energy which may lead to ionization. Additionally the population tends to accumulate in very high n states where ionization is less likely due to fewer rescattering events. Though incomplete, this classical Monte­-Carlo simulation provides useful insights for understanding the experimental observations. This work has been entirely performed at University of Virginia and is supported by the U. S. Department of Energy, Office of Basic energy Sciences.

  10. Electron capture into large-l Rydberg states of multiply charged ions escaping from solid surfaces

    NASA Astrophysics Data System (ADS)

    Nedeljković, N.; Nedeljković, Lj.; Mirković, M.

    2003-07-01

    We have investigated the electron capture into large-l Rydberg states of multiply charged ionic projectiles (e.g., the core charges Z=6, 7, and 8) escaping solid surfaces with intermediate velocities (v≈1 a.u.) in the normal emergence geometry. A model of the nonresonant electron capture from the solid conduction band into the moving large angular-momentum Rydberg states of the ions is developed through a generalization of our results obtained previously for the low-l cases (l=0, 1, and 2). The model is based on the two-wave-function dynamics of the Demkov-Ostrovskii type. The electron exchange process is described by a mixed flux through a moving plane (“Firsov plane”), placed between the solid surface and the ionic projectile. Due to low eccentricities of the large-l Rydberg systems, the mixed flux must be evaluated through the whole Firsov plane. It is for this purpose that a suitable asymptotic method is developed. For intermediate ionic velocities and for all relevant values of the principal quantum number n≈Z, the population probability Pnl is obtained as a nonlinear l distribution. The theoretical predictions concerning the ions S VI, Cl VII, and Ar VIII are compared with the available results of the beam-foil experiments.

  11. Fractional quantum Hall physics with ultracold Rydberg gases in artificial gauge fields

    NASA Astrophysics Data System (ADS)

    Grusdt, F.; Fleischhauer, M.

    2013-04-01

    We study ultracold Rydberg-dressed Bose gases subject to artificial gauge fields in the fractional quantum Hall (FQH) regime. The characteristics of the Rydberg interaction give rise to interesting many-body ground states different from standard FQH physics in the lowest Landau level. The nonlocal but rapidly decreasing interaction potential favors crystalline ground states for very dilute systems. While a simple Wigner crystal becomes energetically favorable compared to the Laughlin liquid for filling fractions ν<1/12, a correlated crystal of composite particles emerges already for ν≤1/6 with a large energy gap to the simple Wigner crystal. The presence of a new length scale, the Rydberg blockade radius aB, gives rise to a bubble crystal phase for ν≲1/4 when the average particle distance becomes less than aB, which describes the region of saturated, almost constant interaction potential. For larger fillings indications for strongly correlated cluster liquids are found.

  12. The importance of multi-level Rydberg interaction in electric field tuned Förster resonances

    NASA Astrophysics Data System (ADS)

    Kondo, Jorge; Booth, Donald; Gonçalves, Luis; Shaffer, James; Marcassa, Luis

    2016-05-01

    Many-body physics has been investigated in ultracold Rydberg atom systems, mainly because important parameters, such as density and interaction strength, can be controlled. Several puzzling experimental observations on Förster resonances have been associated to many-body effects, usually by comparison to complex theoretical models. In this work, we investigate the dc electric field dependence of 2 Förster resonant processes in ultracold 85 Rb, 37D5 / 2 + 37D5 / 2 --> 35 L(L = O , Q) + 39P3 / 2 , as a function of the atomic density in an optical dipole trap. At low densities, the 39 P yield as a function of electric field exhibits resonances. With increasing density, the linewidths increase until the peaks merge. Even under these extreme conditions, where many-body effects were expected to play a role, the 39 P population depends quadratically on the total Rydberg atom population. In order to explain our results, we implement a theoretical model which takes into account the multi-level character of the interactions and Rydberg atom blockade process using only atom pair interactions. The comparison between the experimental data and the model is very good, suggesting that the Förster resonant processes are dominated by 2-body interactions. This work is supported by FAPESP, AFOSR, NSF, INCT-IQ and CNPq.

  13. Strong field radio-frequency measurements using Rydberg states in a vapor cell

    NASA Astrophysics Data System (ADS)

    Miller, Stephanie; Anderson, David; Raithel, Georg

    2016-05-01

    There has been a growing interest in using electromagnetically induced transparency with Rydberg atoms in a room-temperature vapor cell as an all-optical readout method for measuring microwave electric fields. We present results from RF-modulating the 60S1 / 2 and 58D5 / 2 Rydberg states of rubidium with 50 MHz and 100 MHz fields, respectively. Weak RF fields AC Stark-shifts the Rydberg states. As the field strength is increased, sidebands appear at even multiples of the driving frequency. When strong fields are applied, the nearby hydrogenic manifold begins to intersect with the shifted levels. Similar investigations have been performed in cesium. Due to the significant amount of state mixing and level structure, Floquet theory is required to describe the level shifts and mixing. By comparing the calculation with the experimental data, we obtain an absolute determination of the RF electric field reaching a maximum field of 296 V/m to within +/- 0 . 35 % . Additionally, we estimate the shielding of DC fields within the vapor cell.

  14. Retardation (Casimir) effect for a multielectron core system and a Rydberg electron

    NASA Astrophysics Data System (ADS)

    Babb, James F.; Spruch, Larry

    1989-09-01

    Theoretical predictions for the expected Casimir or retardation energy shift ΔEret(n,l) arising from retarded two-photon exchange in a Rydberg helium atom or in Rydberg low-Z heliumlike ions have been available for some time; n and l pertain to the Rydberg electron. These systems consist of a one-electron core [nucleus and 1s electron (e-)] and a Rydberg e-. Recent experiments on the n=10 states of singly excited helium have given a weak confirmation for the presence of Casimir shifts ΔEret(n,l). High-precision confirmation is likely to come from measurements on helium, as experiments improve. Nevertheless, though probably not suitable for high-precision confirmation, a retardation effect could be very large for a system with a many-e- core, and it might then be important to be able to at least estimate that effect. It is shown that the same formalism that was previously developed for the evaluation of ΔEret(n,l) for a one-electron (He-like) core can often be used for the many-electron core. In particular, with the core property characterized by a function F(k) (where k is the wave number of a virtual photon) related to the electric dipole polarizability, if the multi-e- core is in an S state, we obtain essentially the same result as for helium; formally, one need merely replace the F(k) of He+ by the F(k) of the ion under consideration. The extension described is largely notational. Furthermore, we show that as long as the core electrons have a spherically symmetric charge density, for a given core state or for an average over a set of core states which differ only in their angular momentum projections, the result for ΔEret(n,l) is very similar to the heliumlike result. Thus, we give several methods to estimate core properties and ΔEret(n,l) for a variety of systems and use these methods to obtain rough estimates of ΔEret(n,l) for some representative Rydberg levels of Li and Na. We note that storage rings may soon make possible high-precision experiments to

  15. Ab initio calculation of Hubbard parameters for Rydberg-dressed atoms in a one-dimensional optical lattice

    NASA Astrophysics Data System (ADS)

    Chougale, Yashwant; Nath, Rejish

    2016-07-01

    We obtain ab initio the Hubbard parameters for Rydberg-dressed atoms in a one-dimensional (1D) sinusoidal optical lattice on the basis of maximally-localized Wannier states. Finite range, soft-core interatomic interactions become the trait of Rydberg admixed atoms, which can be extended over many neighboring lattice sites. In contrast to dipolar gases, where the interactions follow an inverse cubic law, the key feature of Rydberg-dressed interactions is the possibility of making neighboring couplings to the same magnitude as that of the onsite ones. The maximally-localized Wannier functions (MLWFs) are typically calculated via a spread-minimization procedure (Marzari N and Vanderbilt D 1997 Phys. Rev. B 56 12847) and are always found to be real functions apart from a trivial global phase when an isolated set of Bloch bands are considered. For an isolated single Bloch band, the above procedure reduces to a simple quasi-momentum-dependent unitary phase transformation. Here, instead of minimizing the spread, we employ a diagonal phase transformation which eliminates the imaginary part of the Wannier functions. The resulting Wannier states are found to be maximally localized and in exact agreement with those obtained via a spread-minimization procedure. Using these findings, we calculate the Hubbard couplings from the Rydberg admixed interactions, including dominant density-assisted tunneling (DAT) coefficients. Finally, we provide realistic lattice parameters for the state-of-the-art experimental Rydberg-dressed rubidium setup.

  16. Enhanced production of excited neutrals following core-to-Rydberg excitation in molecules: SiCl4

    NASA Astrophysics Data System (ADS)

    Rosenberg, R. A.; Wen, C.-R.; Tan, K.; Chen, J.-M.

    1990-04-01

    Using monochromatized synchrotron radiation in the range 103 to 112 eV we have monitored the dispersed UV/optical fluorescence resulting from excitation of a Si 2p electron in SiCl4. The main features in the fluorescence spectrum have been identified as emission from the SiCl4+ C state and from excited Si atoms. Features in the fluorescence excitation spectra are assigned to excitation of a Si 2p electron to unoccupied valence and Rydberg orbitals. For the SiCl4+ C state emission there is significant enhancement in the yield following excitation to valence orbitals and very little enhancement as a result of Rydberg excitation. The opposite is true for emission from excited Si atoms. Enhancement in the SiCl4+ C state production upon valence excitation results from autoionization of the core-excited state. The relatively large yield of excited Si atoms following Rydberg excitation is due to the greater probability of the core-excited Rydberg state decaying, via a resonant Auger process, to highly excited, unbound states of SiCl4+. The molecular ion then fragments before the excited Rydberg electron can relax.

  17. Rotationally resolved photoelectron spectra in resonance enhanced multiphoton ionization of HCl via the F 1Δ2 Rydberg state

    NASA Astrophysics Data System (ADS)

    Wang, Kwanghsi; McKoy, V.

    1991-12-01

    Results of studies of rotational ion distributions in the X 2Π3/2 and X 2Π1/2 spin-orbit states of HCl+ resulting from (2+1') resonance enhanced multiphoton ionization (REMPI) via the S(0) branch of the F 1Δ2 Rydberg state are reported and compared with measured threshold-field-ionization zero-kinetic-energy spectra reported recently [K. S. Haber, Y. Jiang, G. Bryant, H. Lefebvre-Brion, and E. R. Grant, Phys. Rev. A (in press)]. These results show comparable intensities for J+=3/2 of the X 2Π3/2 ion and J+=1/2 of the X 2Π1/2 ion. Both transitions require an angular momentum change of ΔN=-1 upon photoionization. To provide further insight into the near-threshold dynamics of this process, we also show rotationally resolved photoelectron angular distributions, alignment of the ion rotational levels, and rotational distributions for the parity components of the ion rotational levels. About 18% population is predicted to occur in the (+) parity component, which would arise from odd partial-wave contributions to the photoelectron matrix element. This behavior is similar to that in (2+1) REMPI via the S(2) branch of the F 1Δ2 state of HBr and was shown to arise from significant l mixing in the electronic continuum due to the nonspherical molecular ion potential. Rotational ion distributions resulting from (2+1) REMPI via the S(10) branch of the F 1Δ2 state are also shown.

  18. Quadratic Zeeman effect in hydrogen Rydberg states: Rigorous bound-state error estimates in the weak-field regime

    SciTech Connect

    Falsaperla, P.; Fonte, G. Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Corso Italia 57, I-95129 Catania )

    1993-05-01

    Applying a method based on some results due to Kato [Proc. Phys. Soc. Jpn. 4, 334 (1949)], we show that series of Rydberg eigenvalues and Rydberg eigenfunctions of hydrogen in a uniform magnetic field can be calculated with a rigorous error estimate. The efficiency of the method decreases as the eigenvalue density increases and as [gamma][ital n][sup 3][r arrow]1, where [gamma] is the magnetic-field strength in units of 2.35[times]10[sup 9] G and [ital n] is the principal quantum number of the unperturbed hydrogenic manifold from which the diamagnetic Rydberg states evolve. Fixing [gamma] at the laboratory value 2[times]10[sup [minus]5] and confining our calculations to the region [gamma][ital n][sup 3][lt]1 (weak-field regime), we obtain extremely accurate results up to states corresponding to the [ital n]=32 manifold.

  19. Direct Electron Impact Excitation of Rydberg-Valence States of Molecular Nitrogen

    NASA Astrophysics Data System (ADS)

    Malone, C. P.; Johnson, P. V.; Liu, X.; Ajdari, B.; Muleady, S.; Kanik, I.; Khakoo, M. A.

    2012-12-01

    Collisions between electrons and neutral N2 molecules result in emissions that provide an important diagnostic probe for understanding the ionospheric energy balance and the effects of space weather in upper atmospheres. Also, transitions to singlet ungerade states cause N2 to be a strong absorber of solar radiation in the EUV spectral range where many ro-vibrational levels of these Rydberg-valence (RV) states are predissociative. Thus, their respective excitation and emission cross sections are important parameters for understanding the [N]/[N2] ratio in the thermosphere of nitrogen dominated atmospheres. The following work provides improved constraints on absolute and relative excitation cross sections of numerous RV states of N2, enabling more physically accurate atmospheric modeling. Here, we present recent integral cross sections (ICSs) for electron impact excitation of RV states of N2 [6], which were based on the differential cross sections (DCSs) derived from electron energy-loss (EEL) spectra of [5]. This work resulted in electronic excitation cross sections over the following measured vibrational levels: b 1Πu (v‧=0-14), c3 1Πu (v‧=0-3), o3 1Πu (v‧=0-3), b‧ 1Σu+ (v‧=0-10), c‧4 1Σu+ (v‧=0-3), G 3Πu (v‧=0-3), and F 3Πu (v‧=0-3). We further adjusted the cross sections of the RV states by extending the vibronic contributions to unmeasured v‧-levels via the relative excitation probabilities (REPs) as discussed in [6]. This resulted in REP-scaled ICSs over the following vibrational levels for the singlet ungerade states: b(0-19), c3(0-4), o3(0-4), b‧(0-16), and c‧4(0-8). Comparison of the ICSs of [6] with available EEL based measurements, theoretical calculations, and emission based work generally shows good agreement within error estimations, except with the recent reevaluation provided by [1]. Further, we have extended these results, using the recent EEL data of [3], to include the unfolding of better resolved features above ~13

  20. Generation of Rydberg states of hydrogen atoms with intense laser pulses: The roles of Coulomb force and initial lateral momentum

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Chen, Wenbo; Zhao, Zengxiu

    2014-08-01

    We investigate the generation of Rydberg states of hydrogen atoms with intense laser pulses by solving the time-dependent Schrödinger equation and by means of classical-trajectory Monte Carlo simulations. Both linearly polarized multicycle pulses and pairs of optical half-cycle pulses are used. Comparisons between these methods show that both the Coulomb force and initial lateral momentum, which have effects on the n distribution and l distribution of the population of excited states, are important in the generation of Rydberg states.

  1. Photofragmentation, state interaction, and energetics of Rydberg and ion-pair states: Resonance enhanced multiphoton ionization of HI

    SciTech Connect

    Hróðmarsson, Helgi Rafn; Wang, Huasheng; Kvaran, Ágúst

    2014-06-28

    Mass resolved resonance enhanced multiphoton ionization data for hydrogen iodide (HI), for two-photon resonance excitation to Rydberg and ion-pair states in the 69 600–72 400 cm{sup −1} region were recorded and analyzed. Spectral perturbations due to homogeneous and heterogeneous interactions between Rydberg and ion-pair states, showing as deformations in line-positions, line-intensities, and line-widths, were focused on. Parameters relevant to photodissociation processes, state interaction strengths and spectroscopic parameters for deperturbed states were derived. Overall interaction and dynamical schemes to describe the observations are proposed.

  2. Resonances and thresholds in the Rydberg-level population of multiply charged ions at solid surfaces

    NASA Astrophysics Data System (ADS)

    Nedeljković, Lj. D.; Nedeljković, N. N.

    1998-12-01

    We present a theoretical study of resonances and thresholds, two specific features of Rydberg-state formation of multiply charged ions (Z=6, 7, and 8) escaping a solid surface at intermediate velocities (v~1 a.u.) in the normal emergence geometry. The resonances are recognized in pronounced maxima of the experimentally observed population curves of Ar VIII ions for resonant values of the principal quantum number n=nres=11 and for the angular momentum quantum numbers l=1 and 2. Absence of optical signals in detectors of beam-foil experiments for n>nthr of S VI and Cl VII ions (with l=0, 1, and 2) and Ar VIII for l=0 is interpreted as a threshold phenomenon. An interplay between resonance and threshold effects is established within the framework of quantum dynamics of the low angular momentum Rydberg-state formation, based on a generalization of Demkov-Ostrovskii's charge-exchange model. In the model proposed, the Ar VIII resonances appear as a consequence of electron tunneling in the very vicinity of the ion-surface potential barrier top and at some critical ion-surface distances Rc. The observed thresholds are explained by means of a decay mechanism of ionic Rydberg states formed dominantly above the Fermi level EF of a solid conduction band. The theoretically predicted resonant and threshold values, nres and nthr of the principal quantum number n, as well as the obtained population probabilities Pnl=Pnl(v,Z), are in sufficiently good agreement with all available experimental findings.

  3. Increasing the Brightness of Cold Ion Beams by Suppressing Disorder-Induced Heating with Rydberg Blockade

    NASA Astrophysics Data System (ADS)

    Murphy, D.; Scholten, R. E.; Sparkes, B. M.

    2015-11-01

    A model for the equilibrium coupling of an ion system with varying initial hard-sphere Rydberg blockade correlations is used to quantify the suppression of disorder-induced heating in Coulomb-expanding cold ion bunches. We show that bunches with experimentally achievable blockade parameters have an emittance reduced by a factor of 2.6 and increased focusability and brightness compared to a disordered bunch. Demonstrating suppression of disorder-induced heating is an important step in the development of techniques for the creation of beam sources with sufficient phase-space density for ultrafast, single-shot coherent diffractive imaging.

  4. Spatially Resolved Observation of Dipole-Dipole Interaction between Rydberg Atoms

    SciTech Connect

    Ditzhuijzen, C. S. E. van; Noordam, L. D.; Heuvell, H. B. van Linden van den; Koenderink, A. F.; Hernandez, J. V.; Robicheaux, F.

    2008-06-20

    We have observed resonant energy transfer between cold Rydberg atoms in spatially separated cylinders. Resonant dipole-dipole coupling excites the 49s atoms in one cylinder to the 49p state while the 41d atoms in the second cylinder are transferred down to the 42p state. We have measured the production of the 49p state as a function of separation of the cylinders (0-80 {mu}m) and the interaction time (0-25 {mu}s). In addition, we measured the width of the electric field resonances. A full many-body quantum calculation reproduces the main features of the experiments.

  5. Neutralization Of Multiply Charged Rydberg Ions Interacting With Solid Surfaces Under The Grazing Incidence Geometry

    NASA Astrophysics Data System (ADS)

    Majkic, M. D.; Nedeljkovic, N. N.; Galijas, S. M. D.

    2010-07-01

    We elaborated the time-symmetric, two-state vector model to investigate the intermediate stages of the electron capture into the Rydberg states of multiply charged ions interacting with solid surface under the grazing incidence geometry. The neutralization distances for the ions XeZ+ interacting with Al-surface are calculated, for core charges Z ?[5,30]. The corresponding mean neutralization distances are in agreement with the data deduced from the measured kinetic energy gain due to the image acceleration of the ions.

  6. Quantum beats in the field ionization of Rydberg atoms in the presence of magnetic fields

    NASA Astrophysics Data System (ADS)

    Gregoric, Vincent C.; Hastings, Hannah; Carroll, Thomas J.; Noel, Michael W.

    2016-05-01

    By exciting a coherent superposition and varying its phase evolution, quantum beats in the selective field ionization of Rydberg atoms have been observed. Here, we present a study exploring the effect of electric and magnetic fields on quantum beats. Beginning with a single excited state, a coherent superposition is created by a short electric field pulse in the presence of a static magnetic field. The resulting quantum beats are then observed in the field ionization spectrum. Additionally, millimeter-wave spectroscopy is used to probe the state populations in this superposition. This work is supported by the National Science Foundation under Grants No. 1205895 and No. 1205897.

  7. Eliminating the dipole phase in attosecond pulse characterization using Rydberg wave packets

    NASA Astrophysics Data System (ADS)

    Pabst, Stefan; Dahlström, Jan Marcus

    2016-07-01

    We propose a technique to fully characterize the temporal structure of extreme ultraviolet pulses by ionizing a bound coherent electronic wave packet. The influence of the dipole phase, which is the main obstacle for state-of-the-art pulse characterization schemes, can be eliminated by angle integration of the photoelectron spectrum. We show that in particular, atomic Rydberg wave packets are ideal and that wave packets involving multiple electronic states provide redundant information that can be used to cross-check the consistency of the phase reconstruction.

  8. Rydberg-London potential for diatomic molecules and unbonded atom pairs.

    PubMed

    Cahill, Kevin; Parsegian, V Adrian

    2004-12-01

    We propose and test a pair potential that is accurate at all relevant distances and simple enough for use in large-scale computer simulations. A combination of the Rydberg potential from spectroscopy and the London inverse-sixth-power energy, the proposed form fits spectroscopically determined potentials better than the Morse, Varnshi, and Hulburt-Hirschfelder potentials and much better than the Lennard-Jones and harmonic potentials. At long distances, it goes smoothly to the London force appropriate for gases and preserves van der Waals's "continuity of the gas and liquid states," which is routinely violated by coefficients assigned to the Lennard-Jones 6-12 form. PMID:15634034

  9. The ionized electron return phenomenon of Rydberg atom in crossed-fields

    NASA Astrophysics Data System (ADS)

    Dong, Chengwei; Wang, Peijie; Du, Mengli; Uzer, Turgay; Lan, Yueheng

    2016-05-01

    Rydberg atom is highly excited with one valence electron being in a high quantum state, which is very far away from the nucleus. The energy level is similar to that of the hydrogen atom. Introducing externally perpendicular electric and magnetic fields breaks the rotation symmetry and the traditional view is that the ionized electron crosses from the bound into the unbound region and will never return. However, we find that when the field is strong enough, the electron does not move off to infinity and there is a certain possibility of return. Three new periodic orbits are found by the variational method and the physical significance of the phenomenon is also discussed.

  10. Multiphoton ionization/dissociation of cyclopentanone at the lower Rydberg states

    NASA Astrophysics Data System (ADS)

    Philis, John G.; Kosmidis, Constantine; Tzallas, Paraskevas

    1998-12-01

    The 2-photon excitation of the 3p and 3d Rydberg states in jet-cooled cyclopentanone has been investigated by resonance enhanced multiphoton ionization (REMPI) in a time of flight mass spectrometer. The three 3px,y,z components are clearly resolved while the case for the 3di excitations is obscure due to the S1 one-photon resonance. The ns laser induced mass spectra are characteristic of hard ionization while the fs laser induced mass spectrum is very similar to the Electron Impact one.

  11. Deterministic single-atom excitation via adiabatic passage and Rydberg blockade

    SciTech Connect

    Beterov, I. I.; Tretyakov, D. B.; Entin, V. M.; Yakshina, E. A.; Ryabtsev, I. I.; MacCormick, C.; Bergamini, S.

    2011-08-15

    We propose to use adiabatic rapid passage with a chirped laser pulse in the strong dipole blockade regime to deterministically excite only one Rydberg atom from randomly loaded optical dipole traps or optical lattices. The chirped laser excitation is shown to be insensitive to the random number N of the atoms in the traps. Our method overcomes the problem of the {radical}(N) dependence of the collective Rabi frequency, which was the main obstacle for deterministic single-atom excitation in the ensembles with unknown N, and can be applied for single-atom loading of dipole traps and optical lattices.

  12. Many-body dynamics of Rydberg excitation using the {Omega} expansion

    SciTech Connect

    Stanojevic, J.; Cote, R.

    2010-05-15

    We investigate the excitation dynamics of Rydberg atoms in ultracold atomic samples by expanding the excitation probability and the correlation function between excited atoms in powers of the isolated atom Rabi frequency {Omega}. In the Heisenberg picture, we give recurrence relations to calculate any order of these expansions, which are expected to be well behaved for arbitrarily strong interactions. For large homogeneous samples, the explicit terms of the expansions, up to {Omega}{sup 4}, are given and then averaged over all possible random spatial distributions of atoms for the most important cases of excitation pulses and interactions.

  13. Magic wavelengths for the 5 s - 18 s transition in rubidium

    NASA Astrophysics Data System (ADS)

    Goldschmidt, Elizabeth; Norris, David; Koller, Silvio; Wyllie, Robert; Brown, Roger; Porto, Trey; Safronova, Ulyana; Safronova, Marianna

    2015-05-01

    Magic wavelengths, for which there is no differential ac Stark shift for the ground and excited state of the atom, allow trapping of excited Rydberg atoms without broadening the optical transition. This is an important tool for implementing quantum gates and other quantum information protocols with Rydberg atoms, and reliable theoretical methods to find such magic wavelengths are thus extremely useful. We use a high-precision all-order method to calculate magic wavelengths for the 5 s - 18 s transition of rubidium near the 18 s - 6 p resonances. We compare the calculation to experiment by measuring the light shift for atoms held in a crossed optical dipole trap with wavelength tuned around the 18 s - 6p3 / 2 resonance at the experimentally convenient wavelength of 1064 nm.

  14. Formation rate for Rb 2 + molecular ions created in collisions of Rb Rydberg and ground-state atoms

    NASA Astrophysics Data System (ADS)

    Stanojevic, Jovica; Côté, Robin

    2016-05-01

    We calculate the formation rate of the molecular Rb2+ion in its various bound states produced in the associative ionization of a Rydberg and a ground-state atom. Before the formation takes place, the colliding atoms are accelerated by an attractive force between the collision partners. In this way the ground-state atom is first captured by the Rydberg electron and then guided towards the positive ion-core where a molecular ion is subsequently formed. As recently demonstrated, this process results in giant collisional cross sections for the molecular ion formation, with the cross sections essentially determined by the size of the Rydberg atom. For sufficient high principal quantum numbers and atomic densities, many ground-state atoms are already located inside the Rydberg atom and ready to participate in the associative ionization. The same process can occur between a Rydberg and a ground-state atom that form a long-range Rydberg molecule, possibly contributing to the shortening of the lifetimes of Rydberg atoms and molecules. Partial support from the US Army Research Office (ARO-MURI W911NF-14-1-0378), and from NSF (Grant No. PHY-1415560).

  15. Influence of inelastic Rydberg atom-atom collisional process on kinetic and optical properties of low-temperature laboratory and astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Klyucharev, A. N.; Bezuglov, N. N.; Mihajlov, A. A.; Ignjatović, Lj M.

    2010-11-01

    Elementary processes in plasma phenomena traditionally attract physicist's attention. The channel of charged-particle formation in Rydberg atom-atom thermal and sub-thermal collisions (the low temperature plasmas conditions) leads to creation of the molecular ions - associative ionization (AI). atomic ions - Penning-like ionization (PI) and the pair of the negative and positive ions. In our universe the chemical composition of the primordial gas consists mainly of Hydrogen and Helium (H, H-, H+, H2, He,He+). Hydrogen-like alkali-metal Lithium (Li, Li+,Li-) and combinations (HeH+, LiH-, LiH+). There is a wide range of plasma parameters in which the Rydberg atoms of the elements mentioned above make the dominant contribution to ionization and that process may be regarded as a prototype of the elementary process of light excitation energy transformation into electric one. The latest stochastic version of chemi-ionisation (AI+PI) on Rydberg atom-atom collisions extends the treatment of the "dipole resonant" model by taking into account redistribution of population over a range of Rydberg states prior to ionization. This redistribution is modelled as diffusion within the frame of stochastic dynamic of the Rydberg electron in the Rydberg energy spectrum. This may lead to anomalies of Rydberg atom spectra. Another result obtained in recent time is understanding that experimental results on chemi-ionization relate to the group of mixed Rydberg atom closed to the primary selected one. The Rydberg atoms ionisation theory today makes a valuable contribution in the deterministic and stochastic approaches correlation in atomic physic.

  16. Rényi, Shannon and Tsallis entropies of Rydberg hydrogenic systems

    NASA Astrophysics Data System (ADS)

    Toranzo, I. V.; Dehesa, J. S.

    2016-02-01

    The Rényi entropies Rp[ρ], 0 of the probability density ρn,l,m(r ) of a physical system completely characterize the chemical and physical properties of the quantum state described by the three integer quantum numbers (n,l,m) . The analytical determination of these quantities is practically impossible up until now, even for the very few systems where their Schrödinger equation is exactly solved. In this work, the Rényi entropies of Rydberg (highly excited) hydrogenic states are explicitly calculated in terms of the quantum numbers and the parameter p. To do that we use a methodology which first connects these quantities to the Lp -norms Nn,l(p) of the Laguerre polynomials which characterize the state's wave function. Then, the Rényi, Shannon and Tsallis entropies of the Rydberg states are determined by calculating the asymptotics (n→∞) of these Laguerre norms. Finally, these quantities are numerically examined in terms of the quantum numbers and the nuclear charge.

  17. Probing the Dynamics of Rydberg and Valence States of Molecular Nitrogen with Attosecond Transient Absorption Spectroscopy.

    PubMed

    Warrick, Erika R; Cao, Wei; Neumark, Daniel M; Leone, Stephen R

    2016-05-19

    An attosecond pulse is used to create a wavepacket in molecular nitrogen composed of multiple bound and autoionizing electronic states of Rydberg and valence character between 12 and 16.7 eV. A time-delayed, few-femtosecond, near-infrared (NIR) laser pulse is used to couple individual states in the wavepacket to multiple neighboring states, resulting in time-dependent modification of the absorption spectrum and revealing both individual quantum beats of the wavepacket and the energy shifts of the excited states in the presence of the strong NIR field. The broad bandwidth of the attosecond pulse and high energy resolution of the extreme ultraviolet spectrometer allow the simultaneous observation of time-dependent dynamics for many individual vibrational levels in each electronic state. Quantum beating with periods from 1.3 to 12 fs and transient line shape changes are observed among vibrational levels of a progression of electronically autoionizing Rydberg states leading to the excited A (2)Πu N2(+) ion core. Vibrational levels in the valence b (1)Πu state exhibit 50 fs oscillation periods, revealing superpositions between individual vibrational levels within this state. Comparisons are made to previous studies of electronic wavepackets in atoms that highlight similarities to atomic behavior yet illustrate unique contributions of the diatomic molecular structure to the wavepacket, including the influence of different electronic potentials and vibrational-level-specific electronic dynamics. PMID:26862883

  18. Rydberg states of helium in electric and magnetic fields of arbitrary relative orientation

    NASA Astrophysics Data System (ADS)

    Tkáč, Ondřej; Žeško, Matija; Agner, Josef A.; Schmutz, Hansjürg; Merkt, Frédéric

    2016-05-01

    A spectroscopic study of Rydberg states of helium (n = 30 and 45) in magnetic, electric and combined magnetic and electric fields with arbitrary relative orientations of the field vectors is presented. The emphasis is on two special cases where (i) the diamagnetic term is negligible and both paramagnetic Zeeman and Stark effects are linear (n = 30, B ≤ 120 mT and F = 0–78 V cm‑1), and (ii) the diamagnetic term is dominant and the Stark effect is linear (n = 45, B = 277 mT and F = 0–8 V cm‑1). Both cases correspond to regimes where the interactions induced by the electric and magnetic fields are much weaker than the Coulomb interaction, but much stronger than the spin–orbit interaction. The experimental spectra are compared to spectra calculated by determining the eigenvalues of the Hamiltonian matrix describing helium Rydberg states in the external fields. The spectra and the calculated energy-level diagrams in external fields reveal avoided crossings between levels of different m l values and pronounced m l -mixing effects at all angles between the electric- and magnetic-field vectors other than 0. These observations are discussed in the context of the development of a method to generate dense samples of cold atoms and molecules in a magnetic trap following Rydberg–Stark deceleration.

  19. Measurement of time-varying electric fields near an atom chip using cold Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Carter, J. D.; Martin, J. D. D.

    2013-05-01

    Inhomogeneous fluctuating electric fields near metal surfaces cause undesired heating or decoherence in devices which confine atoms or ions near such a surface (microfabricated ion traps or proposed gas-phase atom/solid-state hybrid quantum systems, for example). Heating of the motion of trapped ions has been used to measure the noise spectral density of these fields but the microscopic mechanism responsible is unknown. We have implemented a complementary measurement technique using cold atoms released from an atom chip and excited to Rydberg states. The dephasing of a coherent superposition of two Rydberg states is used to measure the inhomogeneous electric field, and spin-echo techniques are used to constrain the frequency scaling of the noise spectral density. Compared to ion trap measurements, this technique has the advantage of flexibility in varying parameters such as atom-surface distance since the atoms do not need to be trapped. Field noise at levels typical for room temperature ion traps is detectable in principle, though the frequency resolution and ultimate sensitivity are inferior to ion traps. Work performed in collaboration with O. Cherry and supported by NSERC.

  20. Trilobites and other molecular animals: How Rydberg-electrons catch ground state atoms

    NASA Astrophysics Data System (ADS)

    Pfau, Tilman

    2012-06-01

    We report on laser spectroscopy results obtained in a dense and frozen Rydberg gas. Novel molecular bonds resulting in ultralong-range Rydberg dimers were predicted [1] and dimers as well as trimers in different vibrational states were found [2]. Some of these states are predicted to be bound by quantum reflection. Lifetime measurements confirm this prediction. Coherent superposition between free and bound states have been investigated [3]. Recently we have also confirmed that in an electric field these homonuclear molecules develop a permanent dipole moment [4]. [4pt] [1] C. H. Greene, A. S. Dickinson, and H. R. Sadeghpour, Phys. Rev. Lett. 85, 2458 (2000). [0pt] [2] V. Bendkowsky, B. Butscher, J. Nipper, J. P. Shaffer, R. L"ow, T. Pfau, Nature 458, 1005 (2009), V. Bendkowsky, B. Butscher, J. Nipper, J. Balewski, J. P. Shaffer, R. L"ow, T. Pfau, W. Li, J. Stanojevic, T. Pohl, and J. M. Rost, Phys. Rev. Lett. 105, 163201 (2010). [0pt] [3] B. Butscher, J. Nipper, J. B. Balewski, L. Kukota, V. Bendkowsky, R. L"ow, and T. Pfau Nature Physics 6, 970--974 (2010). [0pt] [4] W. Li, T. Pohl, J. M. Rost, Seth T. Rittenhouse, H. R. Sadeghpour, J. Nipper, B. Butscher, J. B. Balewski, V. Bendkowsky, R. L"ow, T. Pfau, Science 334, 1110 (2011).

  1. Photoionization microscopy of Rydberg hydrogen atom in a non-uniform electrical field

    NASA Astrophysics Data System (ADS)

    Shao-Hao, Cheng; De-Hua, Wang; Zhao-Hang, Chen; Qiang, Chen

    2016-06-01

    In this paper, we investigate the photoionization microscopy of the Rydberg hydrogen atom in a gradient electric field for the first time. The observed oscillatory patterns in the photoionization microscopy are explained within the framework of the semiclassical theory, which can be considered as a manifestation of interference between various electron trajectories arriving at a given point on the detector plane. In contrast with the photoionization microscopy in the uniform electric field, the trajectories of the ionized electron in the gradient electric field will become chaotic. An infinite set of different electron trajectories can arrive at a given point on the detector plane, which makes the interference pattern of the electron probability density distribution extremely complicated. Our calculation results suggest that the oscillatory pattern in the electron probability density distribution depends sensitively on the electric field gradient, the scaled energy and the position of the detector plane. Through our research, we predict that the interference pattern in the electron probability density distribution can be observed in an actual photoionization microscopy experiment once the external electric field strength and the position of the electron detector plane are reasonable. This study provides some references for the future experimental research on the photoionization microscopy of the Rydberg atom in the non-uniform external fields. Project supported by the National Natural Science Foundation of China (Grant No. 11374133) and the Project of Shandong Provincial Higher Educational Science and Technology Program, China (Grant No. J13LJ04).

  2. Quantum simulation of a topological Mott insulator with Rydberg atoms in a Lieb lattice

    NASA Astrophysics Data System (ADS)

    Dauphin, A.; Müller, M.; Martin-Delgado, M. A.

    2016-04-01

    We propose a realistic scheme to quantum simulate the so-far experimentally unobserved topological Mott insulator phase—an interaction-driven topological insulator—using cold atoms in an optical Lieb lattice. To this end, we study a system of spinless fermions in a Lieb lattice, exhibiting repulsive nearest- and next-to-nearest-neighbor interactions and derive the associated zero-temperature phase diagram within mean-field approximation. In particular, we analyze how the interactions can dynamically generate a charge density wave ordered, a nematic, and a topologically nontrivial quantum anomalous Hall phase. We characterize the topology of the different phases by the Chern number and discuss the possibility of phase coexistence. Based on the identified phases, we propose a realistic implementation of this model using cold Rydberg-dressed atoms in an optical lattice. The scheme, which allows one to access, in particular, the topological Mott insulator phase, robustly and independently of its exact position in parameter space, merely requires global, always-on off-resonant laser coupling to Rydberg states and is feasible with state-of-the-art experimental techniques that have already been demonstrated in the laboratory.

  3. A sensitive electrometer based on a Rydberg atom in a Schrödinger-cat state

    NASA Astrophysics Data System (ADS)

    Facon, Adrien; Dietsche, Eva-Katharina; Grosso, Dorian; Haroche, Serge; Raimond, Jean-Michel; Brune, Michel; Gleyzes, Sébastien

    2016-07-01

    Fundamental quantum fluctuations caused by the Heisenberg principle limit measurement precision. If the uncertainty is distributed equally between conjugate variables of the meter system, the measurement precision cannot exceed the standard quantum limit. When the meter is a large angular momentum, going beyond the standard quantum limit requires non-classical states such as squeezed states or Schrödinger-cat-like states. However, the metrological use of the latter has been so far restricted to meters with a relatively small total angular momentum because the experimental preparation of these non-classical states is very challenging. Here we report a measurement of an electric field based on an electrometer consisting of a large angular momentum (quantum number J ≈ 25) carried by a single atom in a high-energy Rydberg state. We show that the fundamental Heisenberg limit can be approached when the Rydberg atom undergoes a non-classical evolution through Schrödinger-cat states. Using this method, we reach a single-shot sensitivity of 1.2 millivolts per centimetre for a 100-nanosecond interaction time, corresponding to 30 microvolts per centimetre per square root hertz at our 3 kilohertz repetition rate. This highly sensitive, non-invasive space- and time-resolved field measurement extends the realm of electrometric techniques and could have important practical applications: detection of individual electrons in mesoscopic devices at a distance of about 100 micrometres with a megahertz bandwidth is within reach.

  4. Spectra and Autoionization Lifetimes of Long-Range Rydberg Molecular States of 85 Rb2

    NASA Astrophysics Data System (ADS)

    Carollo, Ryan; Eyler, Edward; Gould, Phillip; Stwalley, William

    2016-05-01

    We present high-resolution autoionization data and modeling of the 7 p long-range Rydberg molecular states in 85 Rb2. Our process excites a photoassociation resonance in the 1 (0g-) state which decays to v'' = 35 and 36 long-range levels of the a3Σu+ state and to the continuum. These bound molecules are then excited via a single UV photon to target states below the 5 s + 7 p asymptote by a frequency-doubled pulse-amplified CW laser with narrow linewidth, ~ 150 MHz. The long-range portion of the bonding potential is formed by the scattering interaction of the Rydberg electron of a perturbed 7 p atom scattering from a nearby ground-state atom. We use time-of-flight to selectively measure molecular ions, which are formed via autoionization. Using a hyperfine model of the a3Σu+ and its coupling to the X1Σg+ state, we are able to place an upper limit on the autoionization linewidth of 450 MHz, corresponding to a lifetime >= 3 . 5 ×10-10 s. Excited-state hyperfine structure suggests a still-lower linewidth (and thus longer lifetime), but its contribution is not yet fully understood. This work is supported by NSF and AFOSR.

  5. Entanglement and the Jaynes-Cummings model with Rydberg-dressed atoms

    NASA Astrophysics Data System (ADS)

    Biedermann, Grant

    2016-05-01

    Controlling quantum entanglement between parts of a many-body system is the key to unlocking the power of quantum information processing for applications such as quantum computation, high-precision sensing, and simulation of many-body physics. Spin degrees of freedom of ultracold neutral atoms in their ground electronic state provide a natural platform given their long coherence times and our ability to control them with magneto-optical fields, but creating strong coherent coupling between spins has been challenging. We demonstrate for the first time a strong and tunable Rydberg-dressed interaction between spins of individually trapped cesium atoms with energy shifts of order 1 MHz in units of Planck's constant. We spectroscopically demonstrate that this system is isomorphic to a Jaynes-Cummings Hamiltonian, and observe the √{ N} nonlinearity of the Jaynes-Cummings ladder with a single symmetric Rydberg excitation. This interaction enables a ground-state spin-flip blockade, whereby simultaneous hyperfine spin flips of two atoms are blockaded due to their mutual interaction. We employ this spin-flip blockade to rapidly produce single-step Bell-state entanglement between atoms. This work was supported by the Laboratory Directed Research and Development program at Sandia National Laboratories and through the National Science Foundation's Center for Quantum Information and Control NSF-1212445.

  6. Tailoring Rydberg interactions via Förster resonances: state combinations, hopping and angular dependence

    NASA Astrophysics Data System (ADS)

    Paris-Mandoki, Asaf; Gorniaczyk, Hannes; Tresp, Christoph; Mirgorodskiy, Ivan; Hofferberth, Sebastian

    2016-08-01

    Förster resonances provide a highly flexible tool to tune both the strength and the angular shape of interactions between two Rydberg atoms. We give a detailed explanation about how Förster resonances can be found by searching through a large range of possible quantum number combinations. We apply our search method to SS, SD and DD pair states of 87Rb with principal quantum numbers from 30 to 100, taking into account the fine structure splitting of the Rydberg states. We find various strong resonances between atoms with a large difference in principal quantum numbers. We quantify the strength of these resonances by introducing a figure of merit {\\tilde{C}}3 which is independent of the magnetic quantum numbers and geometry to classify the resonances by interaction strength. We further predict to what extent excitation exchange is possible on different resonances and point out limitations of the coherent hopping process. Finally, we discuss the angular dependence of the dipole–dipole interaction and its tunability near resonances.

  7. High teleportation rates using cold-atom-ensemble-based quantum repeaters with Rydberg blockade

    NASA Astrophysics Data System (ADS)

    Solmeyer, Neal; Li, Xiao; Quraishi, Qudsia

    2016-04-01

    We present a simplified version of a repeater protocol in a cold neutral-atom ensemble with Rydberg excitations optimized for two-node entanglement generation and describe a protocol for quantum teleportation. Our proposal draws from previous proposals [B. Zhao et al., Phys. Rev. A 81, 052329 (2010), 10.1103/PhysRevA.81.052329; Y. Han et al., Phys. Rev. A 81, 052311 (2010), 10.1103/PhysRevA.81.052311] that described efficient and robust protocols for long-distance entanglement with many nodes. Using realistic experimental values, we predict an entanglement generation rate of ˜25 Hz and a teleportation rate of ˜5 Hz . Our predicted rates match the current state-of-the-art experiments for entanglement generation and teleportation between quantum memories. With improved efficiencies we predict entanglement generation and teleportation rates of ˜7.8 and ˜3.6 kHz, respectively, representing a two-order-of-magnitude improvement over the currently realized values. Cold-atom ensembles with Rydberg excitations are promising candidates for repeater nodes because collective effects in the ensemble can be used to deterministically generate a long-lived ground-state memory which may be efficiently mapped onto a directionally emitted single photon.

  8. Self-interaction corrected density functional calculations of Rydberg states of molecular clusters: N,N-dimethylisopropylamine

    SciTech Connect

    Gudmundsdóttir, Hildur; Zhang, Yao; Weber, Peter M.; Jónsson, Hannes

    2014-12-21

    Theoretical calculations of Rydberg excited states of molecular clusters consisting of N,N-dimethylisopropylamine molecules using a Perdew-Zunger self-interaction corrected energy functional are presented and compared with results of resonant multiphoton ionization measurements. The binding energy of the Rydberg electron in the monomer is calculated to be 2.79 eV and 2.27 eV in the 3s and 3p state, respectively, which compares well with measured values of 2.88 eV and 2.21 eV. Three different stable configurations of the dimer in the ground state were found using an energy functional that includes van der Waals interaction. The lowest ground state energy conformation has the two N-atoms widely separated, by 6.2 Å, while the Rydberg state energy is lowest for a configuration where the N-atoms of the two molecules come close together, separated by 3.7 Å. This conformational change is found to lower the Rydberg electron binding energy by 0.2 eV. The self-interaction corrected functional gives a highly localized hole on one of the two molecules, unlike results obtained using the PBE functional or the hybrid B3LYP functional which give a delocalized hole. For the trimer, the self-interaction corrected calculation gives a Rydberg electron binding energy lowered further by 0.13 eV as compared with the dimer. The calculated results compare well with trends observed in experimental measurements. The reduction of the Rydberg electron binding energy with cluster size can be ascribed to an effective delocalization of the positive charge of the hole by the induced and permanent dipole moments of the neighboring molecules. A further decrease observed to occur on a time scale of tens of ps can be ascribed to a structural rearrangement of the clusters in the Rydberg state where molecules rotate to orient their dipoles in response to the formation of the localized hole.

  9. Self-interaction corrected density functional calculations of Rydberg states of molecular clusters: N,N-dimethylisopropylamine.

    PubMed

    Gudmundsdóttir, Hildur; Zhang, Yao; Weber, Peter M; Jónsson, Hannes

    2014-12-21

    Theoretical calculations of Rydberg excited states of molecular clusters consisting of N,N-dimethylisopropylamine molecules using a Perdew-Zunger self-interaction corrected energy functional are presented and compared with results of resonant multiphoton ionization measurements. The binding energy of the Rydberg electron in the monomer is calculated to be 2.79 eV and 2.27 eV in the 3s and 3p state, respectively, which compares well with measured values of 2.88 eV and 2.21 eV. Three different stable configurations of the dimer in the ground state were found using an energy functional that includes van der Waals interaction. The lowest ground state energy conformation has the two N-atoms widely separated, by 6.2 Å, while the Rydberg state energy is lowest for a configuration where the N-atoms of the two molecules come close together, separated by 3.7 Å. This conformational change is found to lower the Rydberg electron binding energy by 0.2 eV. The self-interaction corrected functional gives a highly localized hole on one of the two molecules, unlike results obtained using the PBE functional or the hybrid B3LYP functional which give a delocalized hole. For the trimer, the self-interaction corrected calculation gives a Rydberg electron binding energy lowered further by 0.13 eV as compared with the dimer. The calculated results compare well with trends observed in experimental measurements. The reduction of the Rydberg electron binding energy with cluster size can be ascribed to an effective delocalization of the positive charge of the hole by the induced and permanent dipole moments of the neighboring molecules. A further decrease observed to occur on a time scale of tens of ps can be ascribed to a structural rearrangement of the clusters in the Rydberg state where molecules rotate to orient their dipoles in response to the formation of the localized hole. PMID:25527936

  10. Satellites to Delta n = 1 transitions between high-lying levels of multiply ionized atoms

    NASA Astrophysics Data System (ADS)

    Koenig, R.; Kolk, K.-H.; Koshelev, K. N.; Kunze, H.-J.

    1989-04-01

    In a theta pinch discharge satellites to Delta n = 1 transitions between high-lying levels are observed for the ions Si IX, Si X, and Si XI, but not for Si XII. They are identified as Delta n = 1 transitions between the corresponding levels of doubly excited systems. At high densities, the series of Rydberg levels above their respective thermal limit are collisionally coupled to their ionization limit. The intensity ratio of a transition to that of its satellite thus offers the unique possibility of measuring the ratio of the population density in the ground energy level of the next ionization stage to that in the lowest excited levels of this ion.

  11. Comparison of effective rate coefficients for high energy charge-exchange with measurements of the Rydberg series of Ar16+ at the tokamak TEXTOR

    NASA Astrophysics Data System (ADS)

    Schlummer, T.; Marchuk, O.; Schultz, D. R.; Bertschinger, G.; Biel, W.; Reiter, D.; the TEXTOR-Team

    2015-07-01

    The charge-exchange (CX) rate coefficients for highly ionized impurity ions play a crucial role in fusion plasma diagnostics. However, till today a substantial difference exists in data for the nl-resolved cross-sections based on the different approximations underlying the classical trajectory Monte Carlo (CTMC) calculations either based on the standard initial momentum distribution of target electron orbits (pCTMC, as in the CX data provided by Whyte et al (1998 Phys. Plasmas 5 3694) and Schultz et al (2010 J. Phys. B: At. Mol. Opt. Phys. 43 144002) or based on the alternate initial radial distribution of orbits (rCTMC, as in the calculations of Errea et al (2006 J. Phys. B: At. Mol. Opt. Phys. 39 L91). In this paper, results of new pCTMC and rCTMC calculations for CX in 16.7, 25, and 50 keV/u Ar17+ + H(1s), H(2s), and H(2p) are compared against X-ray line measurements performed at the tokamak TEXTOR. The Rydberg series (1snp-1s2) and the Kα-spectrum (1s2l-1s2) of He-like argon were measured directly in the beam-line of a 16.7-50 keV/u hydrogen injector. The intensities of the spectral lines are compared to the effective CX rate coefficients utilizing both sets of cross sections. While both data sets show good agreement with respect to the observed impact on the Kα transition, only the pCTMC data allow a consistent description of the CX ‘resonance’ observed on the Rydberg lines around n ≈ 8, 9. Similar to the case of low energy ion-atom interactions reported from different tokamaks, the observed influence of CX is separable into contributions from beam particles in the ground and excited states, respectively. It is shown, that the number of beam excited states nh contributing to the CX signal, where nh is the principal quantum number, is limited to nh ≲ 10, confirming the results of recent collisional-radiative models of beam atoms in parabolic states.

  12. Combined theoretical and experimental study of the valence, Rydberg, and ionic states of chlorobenzene.

    PubMed

    Palmer, Michael H; Ridley, Trevor; Vrønning Hoffmann, Søren; Jones, Nykola C; Coreno, Marcello; de Simone, Monica; Grazioli, Cesare; Zhang, Teng; Biczysko, Malgorzata; Baiardi, Alberto; Peterson, Kirk A

    2016-03-28

    New photoelectron (PE) and ultra violet (UV) and vacuum UV (VUV) spectra have been obtained for chlorobenzene by synchrotron study with higher sensitivity and resolution than previous work and are subjected to detailed analysis. In addition, we report on the mass-resolved (2 + 1) resonance enhanced multiphoton ionization (REMPI) spectra of a jet-cooled sample. Both the VUV and REMPI spectra have enabled identification of a considerable number of Rydberg states for the first time. The use of ab initio calculations, which include both multi-reference multi-root doubles and singles configuration interaction (MRD-CI) and time dependent density functional theoretical (TDDFT) methods, has led to major advances in interpretation of the vibrational structure of the ionic and electronically excited states. Franck-Condon (FC) analyses of the PE spectra, including both hot and cold bands, indicate much more complex envelopes than previously thought. The sequence of ionic states can be best interpreted by our multi-configuration self-consistent field computations and also by comparison of the calculated vibrational structure of the B and C ionic states with experiment; these conclusions suggest that the leading sequence is the same as that of iodobenzene and bromobenzene, namely: X(2)B1(3b1 (-1)) < A(2)A2(1a2 (-1)) < B(2)B2(6b2 (-1)) < C(2)B1(2b1 (-1)). The absorption onset near 4.6 eV has been investigated using MRD-CI and TDDFT calculations; the principal component of this band is (1)B2 and an interpretation based on the superposition of FC and Herzberg-Teller contributions has been performed. The other low-lying absorption band near 5.8 eV is dominated by a (1)A1 state, but an underlying weak (1)B1 state (πσ(∗)) is also found. The strongest band in the VUV spectrum near 6.7 eV is poorly resolved and is analyzed in terms of two ππ(∗) states of (1)A1 (higher oscillator strength) and (1)B2 (lower oscillator strength) symmetries, respectively. The calculated vertical

  13. Combined theoretical and experimental study of the valence, Rydberg and ionic states of fluorobenzene.

    PubMed

    Palmer, Michael H; Ridley, Trevor; Vrønning Hoffmann, Søren; Jones, Nykola C; Coreno, Marcello; de Simone, Monica; Grazioli, Cesare; Zhang, Teng; Biczysko, Malgorzata; Baiardi, Alberto; Peterson, Kirk A

    2016-05-28

    New photoelectron spectra (PES) and ultra violet (UV) and vacuum UV (VUV) absorption spectra of fluorobenzene recorded at higher resolution than previously, have been combined with mass-resolved (2 + 1) and (3 + 1) resonance enhanced multiphoton ionization (REMPI) spectra; this has led to the identification of numerous Rydberg states. The PES have been compared with earlier mass-analyzed threshold ionization and photoinduced Rydberg ionization (PIRI) spectra to give an overall picture of the ionic state sequence. The analysis of these spectra using both equations of motion with coupled cluster singles and doubles (EOM-CCSD) configuration interaction and time dependent density functional theory (TDDFT) calculations have been combined with vibrational analysis of both the hot and cold bands of the spectra, in considerable detail. The results extend several earlier studies on the vibronic coupling leading to conical intersections between the X(2)B1 and A(2)A2 states, and a further trio (B, C, and D) of states. The conical intersection of the X and A states has been explicitly identified, and its structure and energetics evaluated. The energy sequence of the last group is only acceptable to the present study if given as B(2)B2Rydberg state peaks in the VUV absorption and REMPI spectra of fluorobenzene are

  14. Combined theoretical and experimental study of the valence, Rydberg and ionic states of fluorobenzene

    NASA Astrophysics Data System (ADS)

    Palmer, Michael H.; Ridley, Trevor; Vrønning Hoffmann, Søren; Jones, Nykola C.; Coreno, Marcello; de Simone, Monica; Grazioli, Cesare; Zhang, Teng; Biczysko, Malgorzata; Baiardi, Alberto; Peterson, Kirk A.

    2016-05-01

    New photoelectron spectra (PES) and ultra violet (UV) and vacuum UV (VUV) absorption spectra of fluorobenzene recorded at higher resolution than previously, have been combined with mass-resolved (2 + 1) and (3 + 1) resonance enhanced multiphoton ionization (REMPI) spectra; this has led to the identification of numerous Rydberg states. The PES have been compared with earlier mass-analyzed threshold ionization and photoinduced Rydberg ionization (PIRI) spectra to give an overall picture of the ionic state sequence. The analysis of these spectra using both equations of motion with coupled cluster singles and doubles (EOM-CCSD) configuration interaction and time dependent density functional theory (TDDFT) calculations have been combined with vibrational analysis of both the hot and cold bands of the spectra, in considerable detail. The results extend several earlier studies on the vibronic coupling leading to conical intersections between the X2B1 and A2A2 states, and a further trio (B, C, and D) of states. The conical intersection of the X and A states has been explicitly identified, and its structure and energetics evaluated. The energy sequence of the last group is only acceptable to the present study if given as B2B2Rydberg state peaks in the VUV absorption and REMPI spectra of fluorobenzene are very similar to

  15. Combined theoretical and experimental study of the valence, Rydberg, and ionic states of chlorobenzene

    NASA Astrophysics Data System (ADS)

    Palmer, Michael H.; Ridley, Trevor; Vrønning Hoffmann, Søren; Jones, Nykola C.; Coreno, Marcello; de Simone, Monica; Grazioli, Cesare; Zhang, Teng; Biczysko, Malgorzata; Baiardi, Alberto; Peterson, Kirk A.

    2016-03-01

    New photoelectron (PE) and ultra violet (UV) and vacuum UV (VUV) spectra have been obtained for chlorobenzene by synchrotron study with higher sensitivity and resolution than previous work and are subjected to detailed analysis. In addition, we report on the mass-resolved (2 + 1) resonance enhanced multiphoton ionization (REMPI) spectra of a jet-cooled sample. Both the VUV and REMPI spectra have enabled identification of a considerable number of Rydberg states for the first time. The use of ab initio calculations, which include both multi-reference multi-root doubles and singles configuration interaction (MRD-CI) and time dependent density functional theoretical (TDDFT) methods, has led to major advances in interpretation of the vibrational structure of the ionic and electronically excited states. Franck-Condon (FC) analyses of the PE spectra, including both hot and cold bands, indicate much more complex envelopes than previously thought. The sequence of ionic states can be best interpreted by our multi-configuration self-consistent field computations and also by comparison of the calculated vibrational structure of the B and C ionic states with experiment; these conclusions suggest that the leading sequence is the same as that of iodobenzene and bromobenzene, namely: X2B1(3b1-1) < A2A2(1a2-1) < B2B2(6b2-1) < C2B1(2b1-1). The absorption onset near 4.6 eV has been investigated using MRD-CI and TDDFT calculations; the principal component of this band is 1B2 and an interpretation based on the superposition of FC and Herzberg-Teller contributions has been performed. The other low-lying absorption band near 5.8 eV is dominated by a 1A1 state, but an underlying weak 1B1 state (πσ∗) is also found. The strongest band in the VUV spectrum near 6.7 eV is poorly resolved and is analyzed in terms of two ππ∗ states of 1A1 (higher oscillator strength) and 1B2 (lower oscillator strength) symmetries, respectively. The calculated vertical excitation energies of these two

  16. Corrigendum to "New REMPI observations and analyses for Rydberg and ion-pair states of HI" [J. Mol. Spectrosc. 290 (2013) 5-12

    NASA Astrophysics Data System (ADS)

    Hróðmarsson, Helgi Rafn; Wang, Huasheng; Kvaran, Ágúst

    2016-06-01

    This article presents a comprehensive overview of Rydberg and ion-pair states for HI in the two-photon excitation region of 69,600-72,300 cm-1. There are two errors in the paper that need to be addressed. These are associated with (i) the wavelength calibration and (ii) the assignment of the d3Π0(1) Rydberg state spectrum.

  17. Energy shift and state mixing of Rydberg atoms in ponderomotive optical traps

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Robicheaux, F.

    2016-08-01

    We present a degenerate perturbation analysis in the spin–orbit coupled basis for Rydberg atoms in an optical trap. The perturbation matrix is found to be nearly the same for two states with the same total angular momentum j, and orbital angular momentum number l differing by 1, The same perturbation matrices result in the same state-mixing and energy shift. We also study the dependence of state mixing and energy shift on the periodicity and symmetry of the ponderomotive potentials induced by different optical traps. State mixing in a one-dimensional lattice formed with two counterpropagating Gaussian beams is studied and yields a state-dependent trap depth. We also calculate the state-mixing in an optical trap formed by four parallel, separated and highly focused Gaussian beams.

  18. Dispersive radio frequency electrometry using Rydberg atoms in a prism-shaped atomic vapor cell

    NASA Astrophysics Data System (ADS)

    Fan, H. Q.; Kumar, S.; Kübler, H.; Shaffer, J. P.

    2016-05-01

    We introduce a method to measure radio frequency (RF) electric fields (E-fields) using atoms contained in a prism-shaped vapor cell. The method utilizes the concept of electromagnetically induced transparency with Rydberg atoms. The RF E-field induces changes in the index of refraction of the vapor resulting in deflection of the probe laser beam as it passes through the prism-shaped vapor cell. We measured a minimum RF E-field of 8.25 μ {{Vcm}}-1 with a sensitivity of ∼ 46.5 μ {{Vcm}}-1 {{Hz}}-1/2. The experimental results agree with a numerical model that includes dephasing effects. We discuss possible improvements to obtain higher sensitivity for RF E-field measurements.

  19. Electric-Field-Induced Dissociation of Heavy Rydberg Ion-Pair States

    SciTech Connect

    Reinhold, Carlos O; Yoshida, S.; Dunning, F. B.

    2011-01-01

    A classical trajectory Monte Carlo approach is used to simulate the dissociation of H+..F and K+..Cl heavy Rydberg ion pairs induced by a ramped electric-field, a technique used experimentally to detect and probe ion-pair states. The simulations include the effects of the strong short-range repulsive interaction associated with ion-pair scattering and provide results in good agreement with experimental data for Stark wavepackets probed by a ramped field, demonstrating that many of the characteristics of field-induced dissociation can be well described using a purely classical model. The data also show that states with a given value of principal quantum number (i.e., binding energy) can dissociate over a broad range of applied fields, the exact field being governed by the initial orbital angular momentum and orientation of the state.

  20. Coherent states of the driven Rydberg atom: Quantum-classical correspondence of periodically driven systems

    SciTech Connect

    Vela-Arevalo, Luz V.; Fox, Ronald F.

    2005-06-15

    A methodology to calculate generalized coherent states for a periodically driven system is presented. We study wave packets constructed as a linear combination of suitable Floquet states of the three-dimensional Rydberg atom in a microwave field. The driven coherent states show classical space localization, spreading, and revivals and remain localized along the classical trajectory. The microwave strength and frequency have a great effect in the localization of Floquet states, since quasienergy avoided crossings produce delocalization of the Floquet states, showing that tuning of the parameters is very important. Using wavelet-based time-frequency analysis, the classical phase-space structure is determined, which allows us to show that the driven coherent state is located in a large regular region in which the z coordinate is in resonance with the external field. The expectation values of the wave packet show that the driven coherent state evolves along the classical trajectory.

  1. Excitation of high orbital angular momentum Rydberg states with Laguerre-Gauss beams

    NASA Astrophysics Data System (ADS)

    Rodrigues, J. D.; Marcassa, L. G.; Mendonça, J. T.

    2016-04-01

    We consider the excitation of Rydberg states through photons carrying an intrinsic orbital angular momentum degree of freedom. Laguerre-Gauss modes, with a helical wave-front structure, correspond to such a set of laser beams, which carry {{\\ell }}0 units of orbital angular momentum in their propagation direction, with ℓ 0 the winding number. We demonstrate that, in a proper geometry setting, this orbital angular momentum can be transferred to the internal degrees of freedom of the atoms, thus violating the standard dipole selection rules. Higher orbital angular momentum states become accessible through a single photon excitation process. We investigate how the spacial structure of the Laguerre-Gauss beam affects the radial coupling strength, assuming the simplest case of hydrogen-like wavefunctions. Finally we discuss a generalization of the angular momentum coupling, in order to include the effects of the fine and hyperfine splitting, in the context of the Wigner-Eckart theorem.

  2. Coherent states of the driven Rydberg atom: Quantum-classical correspondence of periodically driven systems

    NASA Astrophysics Data System (ADS)

    Vela-Arevalo, Luz V.; Fox, Ronald F.

    2005-06-01

    A methodology to calculate generalized coherent states for a periodically driven system is presented. We study wave packets constructed as a linear combination of suitable Floquet states of the three-dimensional Rydberg atom in a microwave field. The driven coherent states show classical space localization, spreading, and revivals and remain localized along the classical trajectory. The microwave strength and frequency have a great effect in the localization of Floquet states, since quasienergy avoided crossings produce delocalization of the Floquet states, showing that tuning of the parameters is very important. Using wavelet-based time-frequency analysis, the classical phase-space structure is determined, which allows us to show that the driven coherent state is located in a large regular region in which the z coordinate is in resonance with the external field. The expectation values of the wave packet show that the driven coherent state evolves along the classical trajectory.

  3. Quantum chaos and breaking of all anti-unitary symmetries in Rydberg excitons.

    PubMed

    Aßmann, Marc; Thewes, Johannes; Fröhlich, Dietmar; Bayer, Manfred

    2016-07-01

    Symmetries are the underlying principles of fundamental interactions in nature. Chaos in a quantum system may emerge from breaking these symmetries. Compared to vacuum, crystals are attractive for studying quantum chaos, as they not only break spatial isotropy, but also lead to novel quasiparticles with modified interactions. Here we study yellow Rydberg excitons in cuprous oxide which couple strongly to the vacuum light field and interact significantly with crystal phonons, leading to inversion symmetry breaking. In a magnetic field, time-reversal symmetry is also broken and the exciton states show a complex splitting pattern, resulting in quadratic level repulsion for small splittings. In contrast to atomic chaotic systems in a magnetic field, which show only a linear level repulsion, this is a signature of a system where all anti-unitary symmetries are broken simultaneously. This behaviour can otherwise be found only for the electro-weak interaction or engineered billiards. PMID:27064527

  4. Electrostatic trapping and in situ detection of Rydberg atoms above chip-based transmission lines

    NASA Astrophysics Data System (ADS)

    Lancuba, P.; Hogan, S. D.

    2016-04-01

    Beams of helium atoms in Rydberg-Stark states with principal quantum number n = 48 and electric dipole moments of 4600 D have been decelerated from a mean initial longitudinal speed of 2000 m s-1 to zero velocity in the laboratory-fixed frame-of-reference in the continuously moving electric traps of a transmission-line decelerator. In this process accelerations up to -1.3× {10}7 m s-2 were applied, and changes in kinetic energy of {{Δ }}{E}{kin}=1.3× {10}-20 J ({{Δ }}{E}{kin}/e=83 meV) per atom were achieved. Guided and decelerated atoms, and those confined in stationary electrostatic traps, were detected in situ by pulsed electric field ionisation. The results of numerical calculations of particle trajectories within the decelerator have been used to characterise the observed deceleration efficiencies, and aid in the interpretation of the experimental data.

  5. Simulations of the angular dependence of the dipole–dipole interaction among Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Bigelow, Jacob L.; Paul, Jacob T.; Peleg, Matan; Sanford, Veronica L.; Carroll, Thomas J.; Noel, Michael W.

    2016-08-01

    The dipole–dipole interaction between two Rydberg atoms depends on the relative orientation of the atoms and on the change in the magnetic quantum number. We simulate the effect of this anisotropy on the energy transport in an amorphous many atom system subject to a homogeneous applied electric field. We consider two experimentally feasible geometries and find that the effects should be measurable in current generation imaging experiments. In both geometries atoms of p character are localized to a small region of space which is immersed in a larger region that is filled with atoms of s character. Energy transfer due to the dipole–dipole interaction can lead to a spread of p character into the region initially occupied by s atoms. Over long timescales the energy transport is confined to the volume near the border of the p region which suggests Anderson localization. We calculate a correlation length of 6.3 μm for one particular geometry.

  6. Emergence of a Metallic Quantum Solid Phase in a Rydberg-Dressed Fermi Gas

    NASA Astrophysics Data System (ADS)

    Li, Wei-Han; Hsieh, Tzu-Chi; Mou, Chung-Yu; Wang, Daw-Wei

    2016-07-01

    We examine possible low-temperature phases of a repulsively Rydberg-dressed Fermi gas in a three-dimensional free space. It is shown that the collective density excitations develop a roton minimum, which is softened at a wave vector smaller than the Fermi wave vector when the particle density is above a critical value. The mean field calculation shows that, unlike the insulating density wave states often observed in conventional condensed matters, a self-assembled metallic density wave state emerges at low temperatures. In particular, the density wave state supports a Fermi surface and a body-centered-cubic crystal order at the same time with the estimated critical temperature being about one tenth of the noninteracting Fermi energy. Our results suggest the emergence of a fermionic quantum solid that should be observable in the current experimental setup.

  7. Emergence of a Metallic Quantum Solid Phase in a Rydberg-Dressed Fermi Gas.

    PubMed

    Li, Wei-Han; Hsieh, Tzu-Chi; Mou, Chung-Yu; Wang, Daw-Wei

    2016-07-15

    We examine possible low-temperature phases of a repulsively Rydberg-dressed Fermi gas in a three-dimensional free space. It is shown that the collective density excitations develop a roton minimum, which is softened at a wave vector smaller than the Fermi wave vector when the particle density is above a critical value. The mean field calculation shows that, unlike the insulating density wave states often observed in conventional condensed matters, a self-assembled metallic density wave state emerges at low temperatures. In particular, the density wave state supports a Fermi surface and a body-centered-cubic crystal order at the same time with the estimated critical temperature being about one tenth of the noninteracting Fermi energy. Our results suggest the emergence of a fermionic quantum solid that should be observable in the current experimental setup. PMID:27472121

  8. Dual species entanglement of Rb and Cs qubits with Rydberg blockade for crosstalk free qubit measurements

    NASA Astrophysics Data System (ADS)

    Baker, Kevin; Yu, Zhaoning; Ebert, Matthew; Sun, Yuan; Saffman, Mark

    2016-05-01

    One of the outstanding challenges facing neutral atom qubit approaches to quantum computation is suppression of crosstalk between proximal qubits due to scattered light that is generated during optical pumping and measurement operations. We have recently proposed a dual species approach to solving this challenge whereby computational qubits encoded in Cs atoms are entangled with Rb atoms via an interspecies Rydberg interaction. The quantum state of a Cs atom can then be readout by measuring the state of a Rb atom. The difference in resonant wavelengths of the two species effectively suppresses crosstalk. We will present progress towards experimental demonstration of dual species entanglement using Rb and Cs atoms cotrapped in a single beam optical trap. Work supported by the ARL CDQI.

  9. Femtosecond predissociation dynamics of the methyl radical from the 3p(z) Rydberg state.

    PubMed

    Balerdi, Garikoitz; Woodhouse, Joanne; Zanchet, Alexander; de Nalda, Rebeca; Senent, María L; García-Vela, Alberto; Bañares, Luis

    2016-01-01

    The real time dynamics of electronic predissociation of the CH3 radical (and its deuterated variant CD3) from selected vibrational states of the 3pz Rydberg state have been measured for the first time using a novel methodology based on a femtosecond three-color experiment to generate, two-photon excite and ionize methyl radicals as a function of time in combination with velocity map imaging detection. Subpicosecond lifetimes have been measured, showing a decreasing trend as vibrational excitation in the symmetric stretch and bending umbrella modes increases for both species. High-level ab initio calculations have been carried out in order to elucidate the CH3 3pz predissociation mechanism and support the lifetime measurements. The observed lifetimes are relevant for the understanding of the resonance enhanced multiphoton ionization spectroscopy of this radical. PMID:26473180

  10. Exponential and nonexponential localization of the one-dimensional periodically kicked Rydberg atom

    SciTech Connect

    Yoshida, S.; Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6373 ; Reinhold, C. O.; Kristoefel, P.; Burgdoerfer, J.; Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6373; Institute for Theoretical Physics, Vienna University of Technology, A1040 Vienna,

    2000-08-01

    We investigate the quantum localization of the one-dimensional Rydberg atom subject to a unidirectional periodic train of impulses. For high frequencies of the train the classical system becomes chaotic and leads to fast ionization. By contrast, the quantum system is found to be remarkably stable. We identify for this system the coexistence of different localization mechanisms associated with resonant and nonresonant diffusion. We find for the suppression of nonresonant diffusion an exponential localization whose localization length can be related to the classical dynamics in terms of the ''scars'' of the unstable periodic orbits. We show that the localization length is determined by the energy excursion along the periodic orbits. The suppression of resonant diffusion along the sequence of photonic peaks is found to be nonexponential due to the presence of high harmonics in the driving force. (c) 2000 The American Physical Society.

  11. Millimeter wave detection via Autler-Townes splitting in rubidium Rydberg atoms

    SciTech Connect

    Gordon, Joshua A. Holloway, Christopher L.; Schwarzkopf, Andrew; Anderson, Dave A.; Miller, Stephanie; Thaicharoen, Nithiwadee; Raithel, Georg

    2014-07-14

    In this paper, we demonstrate the detection of millimeter waves via Autler-Townes splitting in {sup 85}Rb Rydberg atoms. This method may provide an independent, atom-based, SI-traceable method for measuring mm-wave electric fields, which addresses a gap in current calibration techniques in the mm-wave regime. The electric-field amplitude within a rubidium vapor cell in the WR-10 wave guide band is measured for frequencies of 93.71 GHz and 104.77 GHz. Relevant aspects of Autler-Townes splitting originating from a four-level electromagnetically induced transparency scheme are discussed. We measured the E-field generated by an open-ended waveguide using this technique. Experimental results are compared to a full-wave finite element simulation.

  12. A sensitive electrometer based on a Rydberg atom in a Schrödinger-cat state.

    PubMed

    Facon, Adrien; Dietsche, Eva-Katharina; Grosso, Dorian; Haroche, Serge; Raimond, Jean-Michel; Brune, Michel; Gleyzes, Sébastien

    2016-07-14

    Fundamental quantum fluctuations caused by the Heisenberg principle limit measurement precision. If the uncertainty is distributed equally between conjugate variables of the meter system, the measurement precision cannot exceed the standard quantum limit. When the meter is a large angular momentum, going beyond the standard quantum limit requires non-classical states such as squeezed states or Schrödinger-cat-like states. However, the metrological use of the latter has been so far restricted to meters with a relatively small total angular momentum because the experimental preparation of these non-classical states is very challenging. Here we report a measurement of an electric field based on an electrometer consisting of a large angular momentum (quantum number J ≈ 25) carried by a single atom in a high-energy Rydberg state. We show that the fundamental Heisenberg limit can be approached when the Rydberg atom undergoes a non-classical evolution through Schrödinger-cat states. Using this method, we reach a single-shot sensitivity of 1.2 millivolts per centimetre for a 100-nanosecond interaction time, corresponding to 30 microvolts per centimetre per square root hertz at our 3 kilohertz repetition rate. This highly sensitive, non-invasive space- and time-resolved field measurement extends the realm of electrometric techniques and could have important practical applications: detection of individual electrons in mesoscopic devices at a distance of about 100 micrometres with a megahertz bandwidth is within reach. PMID:27411632

  13. Tunable two-dimensional arrays of single Rydberg atoms for realizing quantum Ising models.

    PubMed

    Labuhn, Henning; Barredo, Daniel; Ravets, Sylvain; de Léséleuc, Sylvain; Macrì, Tommaso; Lahaye, Thierry; Browaeys, Antoine

    2016-06-30

    Spin models are the prime example of simplified many-body Hamiltonians used to model complex, strongly correlated real-world materials. However, despite the simplified character of such models, their dynamics often cannot be simulated exactly on classical computers when the number of particles exceeds a few tens. For this reason, quantum simulation of spin Hamiltonians using the tools of atomic and molecular physics has become a very active field over the past years, using ultracold atoms or molecules in optical lattices, or trapped ions. All of these approaches have their own strengths and limitations. Here we report an alternative platform for the study of spin systems, using individual atoms trapped in tunable two-dimensional arrays of optical microtraps with arbitrary geometries, where filling fractions range from 60 to 100 per cent. When excited to high-energy Rydberg D states, the atoms undergo strong interactions whose anisotropic character opens the way to simulating exotic matter. We illustrate the versatility of our system by studying the dynamics of a quantum Ising-like spin-1/2 system in a transverse field with up to 30 spins, for a variety of geometries in one and two dimensions, and for a wide range of interaction strengths. For geometries where the anisotropy is expected to have small effects on the dynamics, we find excellent agreement with ab initio simulations of the spin-1/2 system, while for strongly anisotropic situations the multilevel structure of the D states has a measurable influence. Our findings establish arrays of single Rydberg atoms as a versatile platform for the study of quantum magnetism. PMID:27281203

  14. Adiabatic potential-energy curves of long-range Rydberg molecules: Two-electron R -matrix approach

    NASA Astrophysics Data System (ADS)

    Tarana, Michal; Čurík, Roman

    2016-01-01

    We introduce a computational method developed for study of long-range molecular Rydberg states of such systems that can be approximated by two electrons in a model potential of the atomic cores. Only diatomic molecules are considered. The method is based on a two-electron R -matrix approach inside a sphere centered on one of the atoms. The wave function is then connected to a Coulomb region outside the sphere via a multichannel version of the Coulomb Green's function. This approach is put into a test by its application to a study of Rydberg states of the hydrogen molecule for internuclear distances R from 20 to 400 bohrs and energies corresponding to n from 3 to 22. The results are compared with previous quantum chemical calculations (lower quantum numbers n ) and computations based on contact-potential models (higher quantum numbers n ).

  15. Sub-wavelength imaging and field mapping via electromagnetically induced transparency and Autler-Townes splitting in Rydberg atoms

    SciTech Connect

    Holloway, Christopher L. Gordon, Joshua A.; Schwarzkopf, Andrew; Anderson, David A.; Miller, Stephanie A.; Thaicharoen, Nithiwadee; Raithel, Georg

    2014-06-16

    We present a technique for measuring radio-frequency (RF) electric field strengths with sub-wavelength resolution. We use Rydberg states of rubidium atoms to probe the RF field. The RF field causes an energy splitting of the Rydberg states via the Autler-Townes effect, and we detect the splitting via electromagnetically induced transparency (EIT). We use this technique to measure the electric field distribution inside a glass cylinder with applied RF fields at 17.04 GHz and 104.77 GHz. We achieve a spatial resolution of ≈100 μm, limited by the widths of the laser beams utilized for the EIT spectroscopy. We numerically simulate the fields in the glass cylinder and find good agreement with the measured fields. Our results suggest that this technique could be applied to image fields on a small spatial scale over a large range of frequencies, up into the sub-terahertz regime.

  16. Double, Rydberg and Charge Transfer Excitations from Pairing Matrix Fluctuation and Particle-Particle Random Phase Approximation

    NASA Astrophysics Data System (ADS)

    Yang, Yang; van Aggelen, Helen; Yang, Weitao

    2014-03-01

    Double, Rydberg and charge transfer (CT) excitations have been great challenges for time-dependent density functional theory (TDDFT). Starting from an (N +/- 2) -electron single-determinant reference, we investigate excitations for the N-electron system through the pairing matrix fluctuation, which contains information on two-electron addition/removal processes. We adopt the particle-particle random phase approximation (pp-RPA) and the particle-particle Tamm-Dancoff approximation (pp-TDA) to approximate the pairing matrix fluctuation and then determine excitation energies by the differences of two-electron addition/removal energies. This approach captures all types of interesting excitations: single and double excitations are described accurately, Rydberg excitations are in good agreement with experimental data and CT excitations display correct 1/R dependence. Furthermore, the pp-RPA and the pp-TDA have a computational cost similar to TDDFT and consequently are promising for practical calculations.

  17. Double, Rydberg and charge transfer excitations from pairing matrix fluctuation and particle-particle random phase approximation

    SciTech Connect

    Yang, Yang; Aggelen, Helen van; Yang, Weitao

    2013-12-14

    Double, Rydberg, and charge transfer (CT) excitations have been great challenges for time-dependent density functional theory (TDDFT). Starting from an (N ± 2)-electron single-determinant reference, we investigate excitations for the N-electron system through the pairing matrix fluctuation, which contains information on two-electron addition/removal processes. We adopt the particle-particle random phase approximation (pp-RPA) and the particle-particle Tamm-Dancoff approximation (pp-TDA) to approximate the pairing matrix fluctuation and then determine excitation energies by the differences of two-electron addition/removal energies. This approach captures all types of interesting excitations: single and double excitations are described accurately, Rydberg excitations are in good agreement with experimental data and CT excitations display correct 1/R dependence. Furthermore, the pp-RPA and the pp-TDA have a computational cost similar to TDDFT and consequently are promising for practical calculations.

  18. Double, Rydberg and charge transfer excitations from pairing matrix fluctuation and particle-particle random phase approximation

    NASA Astrophysics Data System (ADS)

    Yang, Yang; van Aggelen, Helen; Yang, Weitao

    2013-12-01

    Double, Rydberg, and charge transfer (CT) excitations have been great challenges for time-dependent density functional theory (TDDFT). Starting from an (N ± 2)-electron single-determinant reference, we investigate excitations for the N-electron system through the pairing matrix fluctuation, which contains information on two-electron addition/removal processes. We adopt the particle-particle random phase approximation (pp-RPA) and the particle-particle Tamm-Dancoff approximation (pp-TDA) to approximate the pairing matrix fluctuation and then determine excitation energies by the differences of two-electron addition/removal energies. This approach captures all types of interesting excitations: single and double excitations are described accurately, Rydberg excitations are in good agreement with experimental data and CT excitations display correct 1/R dependence. Furthermore, the pp-RPA and the pp-TDA have a computational cost similar to TDDFT and consequently are promising for practical calculations.

  19. Implementation of a multiqubit quantum phase gate in a neutral atomic ensemble via the asymmetric Rydberg blockade

    NASA Astrophysics Data System (ADS)

    Wu, Huai-Zhi; Yang, Zhen-Biao; Zheng, Shi-Biao

    2010-09-01

    We report a scheme for implementing a multiqubit quantum phase gate in a neutral atomic ensemble via an asymmetric Rydberg blockade. The multiqubit gate is successfully realized by following a three-step approach. The neutral-atom qubits are always illuminated by the common laser beams and therefore individual addressing of the atoms is not required. The gate errors induced by atomic spontaneous emission, imperfect excitation blockade, and atomic motion are discussed.

  20. Long lifetimes of high molecular Rydberg states in crossed magnetic and electric fields: An experimental and classical computational study

    NASA Astrophysics Data System (ADS)

    Mühlpfordt, Annette; Even, U.; Rabani, Eran; Levine, R. D.

    1995-05-01

    Crossed magnetic and electric fields are observed to extend the lifetime of high molecular Rydberg states of DABCO (1,4-Diazabicyclo[2.2.2]octane) well into the microsecond range. The experimental and computational (using classical mechanics and for a diatomic polar core) results agree both on the magnitude of the effect and on its decrease with increasing electrical field. Theoretical considerations suggest that this time-stretching effect is only present for high Rydberg states and/or for not too weak fields. The computed lifetime increases as the magnetic-field strength is decreased but it requires a finite magnetic field for the onset of the effect. The experimental technique of detection of the surviving Rydberg states via their ionization in a delayed field pulse (known as ZEKE spectroscopy) is most easily implemented for high (say, n>100) but not too high (n<400) Rydberg states. In this regime, the magnetic field required for the additional time stretching is larger than that due to the earth but can be significantly weaker than that required to induce extensive chaotic behavior. The results of the numerically exact classical simulations are interpreted using equations of motion, cast in the form of a mapping, which retain terms up to second order in the fields. (The first-order terms are qualitatively and quantitatively not, by themselves, sufficient.) As is to be expected on physical grounds, the origin of the effect is the slow, periodic modulation of the magnitude of the magnetic quantum number ml of the electron due to terms second order in the magnetic field. Since the angular momentum l of the electron is bounded from below by ml, and since it requires a low l for the electron to couple effectively to the molecular core, the presence of the magnetic field provides for an elongation of the time scale which is over and above that made possible due to the periodic motion of l due to the dc electric field.

  1. Two-electron R-matrix approach to calculations of potential-energy curves of long-range Rydberg molecules

    NASA Astrophysics Data System (ADS)

    Tarana, Michal; Čurík, Roman

    2016-05-01

    We introduce a computational method developed for study of long-range molecular Rydberg states of such systems that can be approximated by two electrons in a model potential of the atomic cores. The method is based on a two-electron R-matrix approach inside a sphere centered on one of the atoms. The wave function is then connected to a Coulomb region outside the sphere via a multichannel version of the Coulomb Green's function. This approach is applied to a study of Rydberg states of Rb2 for internuclear separations R from 40 to 320 bohrs and energies corresponding to n from 7 to 30. We report bound states associated with the low-lying 3Po resonance and with the virtual state of the rubidium atom that turn into ion-pair-like bound states in the Coulomb potential of the atomic Rydberg core. The results are compared with previous calculations based on single-electron models employing a zero-range contact-potential and short-range modele potential. Czech Science Foundation (Project No. P208/14-15989P).

  2. Three-step resonant photoionization spectroscopy of Ni and Ge: ionization potential and odd-parity Rydberg levels

    NASA Astrophysics Data System (ADS)

    Kessler, T.; Brück, K.; Baktash, C.; Beene, J. R.; Geppert, Ch; Havener, C. C.; Krause, H. F.; Liu, Y.; Schultz, D. R.; Stracener, D. W.; Vane, C. R.; Wendt, K.

    2007-12-01

    In preparation of a laser ion source, we have investigated multi-step laser ionization via Rydberg and autoionizing states for atomic Ni and Ge using a mass separator with an ion beam energy of 20 keV. For both elements resonant three-step excitation schemes suitable for modern Ti:sapphire laser systems were developed. Rydberg series in the range of principal quantum numbers 20 <= n <= 80 were localized, assigned and quantum numbers were allocated to the individual resonances. Ionization potentials (IP) were extracted from fits of the individual series and quantum defects of individual levels were analysed for confirmation of series assignment. For Ni the ionization potential could be extracted with significantly increased precision compared to literature with a value of EIP (Ni) = 61 619.77(14) cm-1. Also, at least one notable autoionizing state above the first IP was discovered for both elements, and the different ionization schemes via Rydberg or autoionizing states were compared with respect to line shape, ionization efficiency and selectivity.

  3. Modulation and correlation of the radial and angular motions of a Rydberg electron in a resonance microwave field

    SciTech Connect

    Volkov, P A; Efremov, M A; Fedorov, Mikhail V

    2006-08-31

    We discuss the physical sense and interpretation of the Maeda-Gallagher experiment (2004) in which the probability of ionisation of Rydberg Li atoms perturbed by the resonance microwave field by a short half-cycle pulse was measured. The periodic dependence of the ionisation probability w{sub i} on the delay time t{sub 0} of the half-cycle pulse with respect to the instant of switching on the microwave field is found. The oscillation period of the function w{sub i}(t{sub 0}) is equal to the Kepler period of a Rydberg electron. It is shown that the interpretation of this experiment by the authors in terms of localised wave packets has no grounds and neglects basic processes proceeding in the microwave field. An alternative interpretation is proposed and, as the first step, the structure of the Rydberg wave function formed in the resonance microwave field is studied. (papers devoted to the 90th anniversary of a.m.prokhorov)

  4. Shannon entropy as an indicator of atomic avoided crossings for Rydberg potassium atoms interacting with a static electric field

    NASA Astrophysics Data System (ADS)

    He, Yong Lin; Chen, Yan; Han, Jiu Ning; Zhu, Zhi Bin; Xiang, Geng Xiang; Liu, Huai Dong; Ma, Bao Hong; He, De Chun

    2015-12-01

    We propose a method to calculate the positions of avoided crossings for Rydberg potassium in a static electric field by using Shannon entropy. Our method can be divided into two steps. At first we made a rough estimate of the range of the static electric field strength at which the given avoided crossings occur through strength dependence of the Shannon entropies for all the related states. Next, we obtained the position of the given avoided crossing by calculating the Shannon entropies intersection field strength for the two involved states. The Shannon entropies are calculated by using the one-electron wave functions derived from a well-established diagonalization method which is based on B-spline expansion technique and a parametric one-electron model potential. We have used this method to calculate a number of positions of both s and p states of avoided crossings for Rydberg potassium. The results are in excellent agreement with observed and other calculated results by using the ionization energies. Our study proves that Shannon entropy is an efficient information-theoretic parameter for characterization and prediction of avoided crossings of Rydberg potassium in the l-mixing region.

  5. Exploring the high-order harmonic generation from Rydberg states with a fixed Keldysh parameter

    NASA Astrophysics Data System (ADS)

    Ata Bleda, Erdi; Yavuz, Ilhan; Altun, Zikri; Topcu, Turker

    2012-06-01

    The commonly adopted viewpoint that the Keldysh parameter γ determines the dynamical regime of ionization in strong field physics has long been demonstrated to be a misleading one. One can then ask what happens in strong field ionization as relevant parameters, such as laser intensity and frequency, are varied while keeping γ fixed. We present results from our simulations of high-order harmonic generation (HHG) from Rydberg states of a hydrogen atom. We calculate high harmonic spectra from various initial states with n up to 42, where the laser intensities and the frequencies are scaled from those for n=1 in order to maintain a fixed Keldysh parameter γ<1. We find that as we go up in n for a fixed γ, the position of the cut-off scales as ˜1/n^2 in terms of the cut-off law predicted by the three-step model for n=1. However, a secondary cut-off structure forms below this, which moves to lower harmonics as n is increased. This second cut-off splits the plateau into two regions, one higher in yield and below the second cut-off, and the second with lower yield following it. We further investigate the final n-distributions for some of the interesting cases to elucidate the physical mechanism leading to this structure

  6. Dynamics of Bloch State Positronium Emission from MOF Targets Studied via Rydberg TOF Spectroscopy

    NASA Astrophysics Data System (ADS)

    Piñeiro Escalera, Alina; Jones, Adric; Mills, Allen

    2016-05-01

    Recent advances in the efficient production and detection of Rydberg positronium (Ps) have made it possible to perform energy- and angle- resolved time-of-flight (TOF) spectroscopy with Ps. We report here TOF measurements of Ps emission from the metal-oxide framework (MOF) targets, MOF-5 and ZIF-8. MOFs are a recently synthesized class of chemical structures, characterized by high long-range order and large surface area to volume ratios (i.e., they are highly porous and uniform, crystalline materials). Ps is found to be emitted predominantly in a series of monoenergetic peaks, providing clear evidence of Ps Bloch states. Measuring the relative populations of the monoenergetic peaks, as a function of implantation energy and target temperature, provides insight into the target-dependent dynamics of Bloch state Ps. Work supported by the U.S. National Science Foundation Grants No. PHY 1206100 and No. PHY 1040590 and the National Science Foundation Graduate Research Fellowship Progam (NSF-GRFP). DOE BES DE-FG02-13ER46972 (MOF-5 synthesis and characterization).

  7. Many-body localization and symmetry protected topology with ultracold Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Potirniche, Ionut-Dragos; Schleier-Smith, Monika; Vishwanath, Ashvin; Yao, Norman

    The interplay between quantum entanglement and symmetry-protected topological order has led to the classification of gapped, interacting, one dimensional quantum phases. A consequence of this classification is the existence of a diverse set of exactly solvable models, which serve as paradigmatic examples of various SPT orders. The experimental realization of such models has been hampered by the challenge of implementing tunable multi-body interactions. Recently, an alternate strategy has arisen: periodic driving. Indeed, it has been shown that the dynamics of a simple Floquet transverse-field Ising model can mirror that of the celebrated Haldane chain. However, as SPT order is expected only in the ground state while a driven system is expected to heat to infinite temperature, the ability to observe such ``Floquet'' SPT phases remains an open question. Here, we demonstrate that strong disorder, leading to many-body localization, stabilizes SPT order at finite energy densities while also preventing arbitrary heating of the system. Moreover, we propose a natural experimental implementation in a 1D optical lattice of ultracold Rydberg atoms.

  8. Handshake electron transfer from hydrogen Rydberg atoms incident at a series of metallic thin films

    NASA Astrophysics Data System (ADS)

    Gibbard, J. A.; Softley, T. P.

    2016-06-01

    Thin metallic films have a 1D quantum well along the surface normal direction, which yields particle-in-a-box style electronic quantum states. However the quantum well is not infinitely deep and the wavefunctions of these states penetrate outside the surface where the electron is bound by its own image-charge attraction. Therefore a series of discrete, vacant states reach out from the thin film into the vacuum increasing the probability of electron transfer from an external atom or molecule to the thin film, especially for the resonant case where the quantum well energy matches that of the atom. We show that "handshake" electron transfer from a highly excited Rydberg atom to these thin-film states is experimentally measurable. Thicker films have a wider 1D box, changing the energetic distribution and image-state contribution to the thin film wavefunctions, resulting in more resonances. Calculations successfully predict the number of resonances and the nature of the thin-film wavefunctions for a given film thickness.

  9. Handshake electron transfer from hydrogen Rydberg atoms incident at a series of metallic thin films.

    PubMed

    Gibbard, J A; Softley, T P

    2016-06-21

    Thin metallic films have a 1D quantum well along the surface normal direction, which yields particle-in-a-box style electronic quantum states. However the quantum well is not infinitely deep and the wavefunctions of these states penetrate outside the surface where the electron is bound by its own image-charge attraction. Therefore a series of discrete, vacant states reach out from the thin film into the vacuum increasing the probability of electron transfer from an external atom or molecule to the thin film, especially for the resonant case where the quantum well energy matches that of the atom. We show that "handshake" electron transfer from a highly excited Rydberg atom to these thin-film states is experimentally measurable. Thicker films have a wider 1D box, changing the energetic distribution and image-state contribution to the thin film wavefunctions, resulting in more resonances. Calculations successfully predict the number of resonances and the nature of the thin-film wavefunctions for a given film thickness. PMID:27334186

  10. Rydberg systems in parallel electric and magnetic fields: an improved method for finding exceptional points

    NASA Astrophysics Data System (ADS)

    Feldmaier, Matthias; Main, Jörg; Schweiner, Frank; Cartarius, Holger; Wunner, Günter

    2016-07-01

    Exceptional points are special parameter points in spectra of open quantum systems, at which resonance energies become degenerate and the associated eigenvectors coalesce. Typical examples are Rydberg systems in parallel electric and magnetic fields, for which we solve the Schrödinger equation in a complete basis to calculate the resonances and eigenvectors. Starting from an avoided crossing within the parameter-dependent spectra and using a two-dimensional matrix model, we develop an iterative algorithm to calculate the field strengths and resonance energies of exceptional points and to verify their basic properties. Additionally, we are able to visualise the wave functions of the degenerate states. We report the existence of various exceptional points. For the hydrogen atom these points are in an experimentally inaccessible regime of field strengths. However, excitons in cuprous oxide in parallel electric and magnetic fields, i.e., the corresponding hydrogen analogue in a solid state body, provide a suitable system, where the high-field regime can be reached at much smaller external fields and for which we propose an experiment to detect exceptional points.

  11. Rydberg, Valence and Ion-Pair Quintet States of O_2

    NASA Astrophysics Data System (ADS)

    Vazquez, Gabriel J.; Liebermann, Hans P.; Lefebvre-Brion, H.

    2015-06-01

    We carried out a relatively comprehensive ab--initio study of the electronic structure of O_2 and O_2^+. We employed the MRD--CI package together with the cc--pV4Z basis set augmented with seven diffuse functions of s, p and d character on each atom. In this contribution we focus on the quintet states. Potential energy curves of about 50 quintet states were computed. The spectroscopic constants of the six valence quintet states (^5σ^+_g, ^5σ^-_g, ^5σ^-_u, ^5Π_u, ^5Π_g, ^5Δ_g) dissociating to the first dissociation limit O(^3P)+O(^3P) are reported. The four ion--pair quintet states (^5σ^-_g, ^5σ^-_u, ^5Π_g, ^5Π_u) dissociating into O^+(^4S)+O^-(^2P) at 17.28 eV were also computed and their spectroscopic constants will be presented. A number of bound quintet Rydberg states belonging to series converging to the a^4Π_u, b^4σ^-_g, f^4Π_g and ^6σ^+_u states of the O_2^+ cation were identified and attributed. Long--range interactions involving the ion--pair states as they slowly approach their dissociation limit will be shown.

  12. Fractional Quantum Hall Effect of lossy Rydberg Dark-State Polaritons

    NASA Astrophysics Data System (ADS)

    Grusdt, Fabian; Fleischhauer, Michael; Höning, Michael; Otterbach, Johannes

    2012-06-01

    Dark-state-polaritons (DSP) are bosonic quasiparticles arising in the interaction of light with 3-level atoms under conditions of electromagnetically induced transparency (EIT). When exposed to a strong artificial magnetic field, they can enter the lowest Landau level regime. With additional long range interactions, as realized e.g. when the 3-level atom contains a Rydberg-excited state, DSPs are natural candidates for a realization of the bosonic fractional quantum Hall effect. Besides their high controllability, they offer the possibility to examine open quantum Hall systems. We show how highly-correlated quantum Hall states of DSPs can be prepared, making use of nonlinear polariton losses. The possibility of realizing these states as stationary states of open systems is investigated. We propose a realistic quantum-optical setup, and show that different fractional quantum Hall states can be prepared, manipulated and observed. Numerical and analytical results for the excitation gaps of the ν=1/2p Laughlin states are presented.

  13. Positron impact excitations of hydrogen atom embedded in dense quantum plasmas: Formation of Rydberg atoms

    SciTech Connect

    Rej, Pramit; Ghoshal, Arijit

    2014-11-15

    Formation of Rydberg atoms due to 1 s → nlm excitations of hydrogen by positron impact, for arbitrary n, l, m, in dense quantum plasma has been investigated using a distorted wave theory which includes screened dipole polarization potential. The interactions among the charged particles in the plasma have been represented by exponential cosine-screened Coulomb potentials. Making use of a simple variationally determined hydrogen wave function, it has been possible to obtain the distorted wave scattering amplitude in a closed analytical form. A detailed study has been made to explore the structure of differential and total cross sections in the energy range 20–300 eV of incident positron. For the unscreened case, our results agree nicely with some of the most accurate results available in the literature. To the best of our knowledge, such a study on the differential and total cross sections for 1 s → nlm inelastic positron-hydrogen collisions in dense quantum plasma is the first reported in the literature.

  14. Positron impact excitations of hydrogen atom embedded in weakly coupled plasmas: Formation of Rydberg atoms

    SciTech Connect

    Rej, Pramit; Ghoshal, Arijit

    2014-09-15

    Formation of Rydberg atoms due to 1s→nlm excitations of hydrogen, for arbitrary n, l, m, by positron impact in weakly coupled plasma has been investigated using a distorted-wave theory in the momentum space. The interactions among the charged particles in the plasma have been represented by Debye-Huckel potentials. Making use of a simple variationally determined wave function for the hydrogen atom, it has been possible to obtain the distorted-wave scattering amplitude in a closed analytical form. A detailed study has been made on the effects of plasma screening on the differential and total cross sections in the energy range 20–300 eV of incident positron. For the unscreened case, our results agree nicely with some of the most accurate results available in the literature. To the best of our knowledge, such a study on the differential and total cross sections for 1s→nlm inelastic positron-hydrogen collisions for arbitrary n, l, m in weakly coupled plasmas is the first reported in the literature.

  15. Entangling atomic spins with a Rydberg-dressed spin-flip blockade

    NASA Astrophysics Data System (ADS)

    Jau, Y.-Y.; Hankin, A. M.; Keating, T.; Deutsch, I. H.; Biedermann, G. W.

    2016-01-01

    Controlling the quantum entanglement between parts of a many-body system is key to unlocking the power of quantum technologies such as quantum computation, high-precision sensing, and the simulation of many-body physics. The spin degrees of freedom of ultracold neutral atoms in their ground electronic state provide a natural platform for such applications thanks to their long coherence times and the ability to control them with magneto-optical fields. However, the creation of strong coherent coupling between spins has been challenging. Here we demonstrate a strong and tunable Rydberg-dressed interaction between spins of individually trapped caesium atoms with energy shifts of order 1 MHz in units of Planck’s constant. This interaction leads to a ground-state spin-flip blockade, whereby simultaneous hyperfine spin flips of two atoms are inhibited owing to their mutual interaction. We employ this spin-flip blockade to rapidly produce single-step Bell-state entanglement between two atoms with a fidelity >=81(2)%.

  16. Spectroscopic Investigation of the Odd-Parity 3 d 2 D → nf 2 F Transitions of Neutral Sodium

    NASA Astrophysics Data System (ADS)

    Nadeem, A.; Shah, M.; Shahzada, S.; Ahmed, M.; Haq, S. U.

    2015-11-01

    We report new experimental data on term energies and effective quantum numbers of the odd parity Rydberg states of sodium in the 40687-41408 cm-1 energy range. The experiment was performed using a two-color scheme of three-photon laser excitation in conjunction with a thermionic diode ion detector. The new observation includes much extended nf 2 F (12 ≤ n ≤ 51) series excited from the 3 d 2 D intermediate state. In addition, oscillator strengths of the 3 d 2 D → nf 2 F (16 ≤ n ≤ 45) Rydberg transitions have been determined and a complete picture is presented from n = 4-45 incorporating the present work and earlier computed results.

  17. Dynamics of heavy-Rydberg ion-pair formation in K(14p,20p)-SF{sub 6}, CCl{sub 4} collisions

    SciTech Connect

    Wang, C. H.; Kelley, M.; Buathong, S.; Dunning, F. B.

    2014-06-21

    The dynamics of formation of heavy-Rydberg ion-pair states through electron transfer in K(np)-SF{sub 6}, CCl{sub 4} collisions is examined by measuring the velocity, angular, and binding energy distributions of the product ion pairs. The results are analyzed with the aid of a Monte Carlo collision code that models both the initial electron capture and the subsequent evolution of the ion pairs. The model simulations are in good agreement with the experimental data and highlight the factors such as Rydberg atom size, the kinetic energy of relative motion of the Rydberg atom and target particle, and (in the case of attaching targets that dissociate) the energetics of dissociation that can be used to control the properties of the product ion-pair states.

  18. Dynamics of heavy-Rydberg ion-pair formation in K(14p,20p)-SF6, CCl4 collisions

    NASA Astrophysics Data System (ADS)

    Wang, C. H.; Kelley, M.; Buathong, S.; Dunning, F. B.

    2014-06-01

    The dynamics of formation of heavy-Rydberg ion-pair states through electron transfer in K(np)-SF6, CCl4 collisions is examined by measuring the velocity, angular, and binding energy distributions of the product ion pairs. The results are analyzed with the aid of a Monte Carlo collision code that models both the initial electron capture and the subsequent evolution of the ion pairs. The model simulations are in good agreement with the experimental data and highlight the factors such as Rydberg atom size, the kinetic energy of relative motion of the Rydberg atom and target particle, and (in the case of attaching targets that dissociate) the energetics of dissociation that can be used to control the properties of the product ion-pair states.

  19. On the adiabatic preparation of spatially-ordered Rydberg excitations of atoms in a one-dimensional optical lattice by laser frequency sweeps

    NASA Astrophysics Data System (ADS)

    Petrosyan, David; Mølmer, Klaus; Fleischhauer, Michael

    2016-04-01

    We examine the adiabatic preparation of crystalline phases of Rydberg excitations in a one-dimensional lattice gas by frequency sweep of the excitation laser, as proposed by Pohl et al (2010 Phys. Rev. Lett. 104 043002) and recently realized experimentally by Schauß et al (2015 Science 347 1455). We find that the preparation of crystals of a few Rydberg excitations in a unitary system of several tens of atoms requires exceedingly long times for the adiabatic following of the ground state of the system Hamiltonian. Using quantum stochastic (Monte Carlo) wavefunction simulations, we show that realistic decay and dephasing processes affecting the atoms during the preparation lead to a final state of the system that has only a small overlap with the target crystalline state. Yet, the final number and highly sub-Poissonian statistics of Rydberg excitations and their spatial order are little affected by the relaxations.

  20. The Jahn-Teller effect in the 3pe' Rydberg state of H3: review of experimental and ab initio determinations.

    PubMed

    Jungen, Ch; Jungen, M; Pratt, S T

    2012-11-13

    The dissociative recombination (DR) of H(3)(+) ions with electrons, producing neutral atomic and molecular fragments, is driven primarily by the vibronic Jahn-Teller (JT) interaction between the electronic components of the pe' e(-)-H(3)(+) collision (Rydberg) channel. The JT parameters characterizing this interaction are therefore of great interest as they are required for the theoretical predictions of the DR cross section. In this contribution, we review various determinations of these quantities that have been made previously, based both on spectroscopic studies of 3pe' Rydberg-excited H(3) states, and on the analysis of the corresponding ab initio H(3) Rydberg potential surfaces near the conical intersection (D(3h) symmetry) for n=3-5. The highly correlated theoretical 3pe' potential surfaces of Mistrík et al. are used for a new determination of both the linear and quadratic JT terms. PMID:23028155

  1. Ab initio potential energy curves of the valence, Rydberg, and ion-pair states of iodine monochloride, ICl

    SciTech Connect

    Kalemos, Apostolos; Prosmiti, Rita

    2014-09-14

    We present for the first time a coherent ab initio study of 39 states of valence, Rydberg, and ion-pair character of the diatomic interhalogen ICl species through large scale multireference variational methods including spin-orbit effects coupled with quantitative basis sets. Various avoided crossings are responsible for a non-adiabatic behaviour creating a wonderful vista for its theoretical description. Our molecular constants are compared with all available experimental data with the aim to assist experimentalists especially in the high energy regime of up to ∼95 000 cm{sup −1}.

  2. Ionization yield and absorption spectra reveal superexcited Rydberg state relaxation processes in H2O and D2O

    NASA Astrophysics Data System (ADS)

    Fillion, J.-H.; Dulieu, F.; Baouche, S.; Lemaire, J.-L.; Jochims, H. W.; Leach, S.

    2003-07-01

    The absorption cross section and the ionization quantum yield of H2O have been measured using a synchrotron radiation source between 9 and 22 eV. Comparison between the two curves highlights competition between relaxation processes for Rydberg states converging to the first tilde A 2A 1 and to the second tilde B 2B 2 excited states of H2O+. Comparison with D2O absorption and ionization yields, derived from Katayama et al (1973 J. Chem. Phys. 59 4309), reveals specific energy-dependent deuteration effects on competitive predissociation and autoionization relaxation channels. Direct ionization was found to be only slightly affected by deuteration.

  3. Absorbing State Phase Transition with Competing Quantum and Classical Fluctuations.

    PubMed

    Marcuzzi, Matteo; Buchhold, Michael; Diehl, Sebastian; Lesanovsky, Igor

    2016-06-17

    Stochastic processes with absorbing states feature examples of nonequilibrium universal phenomena. While the classical regime has been thoroughly investigated in the past, relatively little is known about the behavior of these nonequilibrium systems in the presence of quantum fluctuations. Here, we theoretically address such a scenario in an open quantum spin model which, in its classical limit, undergoes a directed percolation phase transition. By mapping the problem to a nonequilibrium field theory, we show that the introduction of quantum fluctuations stemming from coherent, rather than statistical, spin flips alters the nature of the transition such that it becomes first order. In the intermediate regime, where classical and quantum dynamics compete on equal terms, we highlight the presence of a bicritical point with universal features different from the directed percolation class in a low dimension. We finally propose how this physics could be explored within gases of interacting atoms excited to Rydberg states. PMID:27367395

  4. Absorbing State Phase Transition with Competing Quantum and Classical Fluctuations

    NASA Astrophysics Data System (ADS)

    Marcuzzi, Matteo; Buchhold, Michael; Diehl, Sebastian; Lesanovsky, Igor

    2016-06-01

    Stochastic processes with absorbing states feature examples of nonequilibrium universal phenomena. While the classical regime has been thoroughly investigated in the past, relatively little is known about the behavior of these nonequilibrium systems in the presence of quantum fluctuations. Here, we theoretically address such a scenario in an open quantum spin model which, in its classical limit, undergoes a directed percolation phase transition. By mapping the problem to a nonequilibrium field theory, we show that the introduction of quantum fluctuations stemming from coherent, rather than statistical, spin flips alters the nature of the transition such that it becomes first order. In the intermediate regime, where classical and quantum dynamics compete on equal terms, we highlight the presence of a bicritical point with universal features different from the directed percolation class in a low dimension. We finally propose how this physics could be explored within gases of interacting atoms excited to Rydberg states.

  5. Energy levels and radiative transition rates for Ba XLVIII

    NASA Astrophysics Data System (ADS)

    Khatri, Indu; Goyal, Arun; Aggarwal, Sunny; Singh, A. K.; Mohan, Man

    2016-01-01

    Energy levels and radiative rates are reported for transitions in F-like Ba XLVIII. Configuration interaction has been included among 27 configurations (generating 431 levels) over a wide energy range up to 618 Rydbergs, and the fully relativistic multi-configurational Dirac-Fock method adopted for the calculations. To assess the accuracy, calculations have also been performed with the flexible atomic code, FAC. Radiative rates, oscillator strengths and line strengths are reported for all electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole transitions from the lowest 3 levels, although calculations have been performed for a much larger number of levels. We have made comparisons of our results with existing available results and a good agreement has been achieved. Additionally, lifetimes for all 431 levels are listed.

  6. Transition Planning

    ERIC Educational Resources Information Center

    Statfeld, Jenna L.

    2011-01-01

    Post-school transition is the movement of a child with disabilities from school to activities that occur after the completion of school. This paper provides information about: (1) post-school transition; (2) transition plan; (3) transition services; (4) transition planning; (5) vocational rehabilitation services; (6) services that are available…

  7. Rydberg Spectroscopy of Zeeman-Decelerated Beams of Metastable Helium Molecules

    NASA Astrophysics Data System (ADS)

    Jansen, Paul; Motsch, Michael; Sprecher, Daniel; Merkt, Frederic

    2014-06-01

    Having three and four electrons, respectively, He_2^+ and He_2 represent systems for which highly accurate ab-initio calculations might become feasible in the near future. With the goal of performing accurate measurements of the rovibrational energy-level structure of He_2^+ by Rydberg spectroscopy of He_2 and multichannel quantum-defect theory extrapolation techniques, we have produced samples of helium molecules in the a ^3Σu^+ state in supersonic beams with velocities tunable down to 100 m/s by combining a cryogenic supersonic-beam source with a multistage Zeeman decelerator. The molecules are formed at an initial velocity of 500 m/s by striking a discharge in the pulsed expansion of helium gas from a reservoir kept at a cryogenic temperature of 10 K. Using rotationally-resolved PFI-ZEKE (pulsed-field-ionization zero-kinetic-energy) photoelectron spectroscopy, we have probed the rotational-state distribution of the molecules produced in the discharge and found vibrational levels up to ν" = 2 and rotational levels up to N"=21 to be populated. The molecular beam is coupled to a multistage Zeeman decelerator that employs pulsed inhomogeneous magnetic fields to further reduce the beam velocity. By measuring the quantum-state distribution of the decelerated sample using photoelectron and photoionization spectroscopy we observed no rotational or vibrational state-selectivity of the deceleration process, but found that one of the three spin-rotation components of the He_2 a ^3Σu^+ rotational levels is eliminated. W.-C. Tung, M. Pavanello, L. Adamowicz, J. Chem. Phys. 136, 104309 (2012). D. Sprecher, J. Liu, T. Krähenmann, M. Schäfer, and F. Merkt, J. Chem. Phys. 140, 064304 (2014). M. Motsch, P. Jansen, J. A. Agner, H. Schmutz, and F. Merkt, arXiv:1401.7774. N. Vanhaecke, U. Meier, M. Andrist, B. H. Meier, and F. Merkt, Phys. Rev. A 75, 031402(R) (2007).

  8. Retardation (Casimir) energy shifts for Rydberg helium-like low-Z ions: An exploratory study

    NASA Astrophysics Data System (ADS)

    Babb, James F.; Habs, Dietrich; Spruch, Larry; Wolf, Andreas

    1992-09-01

    The development of storage rings and electromagnetic traps for heavy charged particles is opening up new regimes of atomic physics, including, in particular, spectroscopic studies of Rydberg helium-like ions — with nuclear charge Z, one electron in the 1 s state, and one electron in a near-hydrogenic state of high n and l < n, with n and l the principal and orbital quantum numbers, respectively. We consider the possibility of detecting energy shifts due to retardation, Δ E ret ( n, l), Casimir-like effects. These are quantum electrodynamic (QED) retardation effects associated with the finite speed of light. (As opposed to basically kinematic and dynamic QED effects for small quantum numbers n and l, the appropriate expansion parameter for n and l large for retardation QED corrections is not Z( e 2/ħ c) but [( Z - 1)/ n 2 Z 2](ħ c/e 2).) We wish to provide some orientation to those planning experiments in the area, with regard to the choices of n, l, and Z most likely to be able to generate a high-precision confirmation of a retarded interaction. To do so, we provide extensive tables of estimates, for 1 s, nl states, of Δ E ret( n, l), of radiative widths, and of E, the spin-independent (“electric” fine structure) energy in the absence of retardation shifts, for (nuclear spin zero) ions with Z=2, 6, 8, 16 and 20. These ions might be experimentally accessible in storage rings, and the Z's are low enough that virtual pair production effects may not yet be significant. There is also a brief survey of possible experimental techniques.

  9. Light in Condensed Matter in the Upper Atmosphere as the Origin of Homochirality: Circularly Polarized Light from Rydberg Matter

    NASA Astrophysics Data System (ADS)

    Holmlid, Leif

    2009-08-01

    Clouds of the condensed excited Rydberg matter (RM) exist in the atmospheres of comets and planetary bodies (most easily observed at Mercury and the Moon), where they surround the entire bodies. Vast such clouds are recently proposed to exist in the upper atmosphere of Earth (giving rise to the enormous features called noctilucent clouds, polar mesospheric clouds, and polar mesospheric summer radar echoes). It has been shown in experiments with RM that linearly polarized visible light scattered from an RM layer is transformed to circularly polarized light with a probability of approximately 50%. The circular Rydberg electrons in the magnetic field in the RM may be chiral scatterers. The magnetic and anisotropic RM medium acts as a circular polarizer probably by delaying one of the perpendicular components of the light wave. The delay process involved is called Rabi-flopping and gives delays of the order of femtoseconds. This strong effect thus gives intense circularly polarized visible and UV light within RM clouds. Amino acids and other chiral molecules will experience a strong interaction with this light field in the upper atmospheres of planets. The interaction will vary with the stereogenic conformation of the molecules and in all probability promote the survival of one enantiomer. Here, this strong effect is proposed to be the origin of homochirality. The formation of amino acids in the RM clouds is probably facilitated by the catalytic effect of RM.

  10. Light in condensed matter in the upper atmosphere as the origin of homochirality: circularly polarized light from Rydberg matter.

    PubMed

    Holmlid, Leif

    2009-01-01

    Clouds of the condensed excited Rydberg matter (RM) exist in the atmospheres of comets and planetary bodies (most easily observed at Mercury and the Moon), where they surround the entire bodies. Vast such clouds are recently proposed to exist in the upper atmosphere of Earth (giving rise to the enormous features called noctilucent clouds, polar mesospheric clouds, and polar mesospheric summer radar echoes). It has been shown in experiments with RM that linearly polarized visible light scattered from an RM layer is transformed to circularly polarized light with a probability of approximately 50%. The circular Rydberg electrons in the magnetic field in the RM may be chiral scatterers. The magnetic and anisotropic RM medium acts as a circular polarizer probably by delaying one of the perpendicular components of the light wave. The delay process involved is called Rabi-flopping and gives delays of the order of femtoseconds. This strong effect thus gives intense circularly polarized visible and UV light within RM clouds. Amino acids and other chiral molecules will experience a strong interaction with this light field in the upper atmospheres of planets. The interaction will vary with the stereogenic conformation of the molecules and in all probability promote the survival of one enantiomer. Here, this strong effect is proposed to be the origin of homochirality. The formation of amino acids in the RM clouds is probably facilitated by the catalytic effect of RM. PMID:19586392

  11. Observation of intracluster Coulombic decay of Rydberg-like states triggered by intense near-infrared pulses

    NASA Astrophysics Data System (ADS)

    Schütte, Bernd; Arbeiter, Mathias; Fennel, Thomas; Jabbari, Ghazal; Gokhberg, Kirill; Kuleff, Alexander I.; Vrakking, Marc J. J.; Rouzée, Arnaud

    2015-05-01

    Interatomic Coulombic decay (ICD) describes a process, where an excited atom relaxes by transferring its energy to an atom in the environment that gets ionized. So far, ICD has been observed following XUV ionization or excitation of clusters. Here we present novel results of an intracluster Coulombic decay mechanism induced by intense NIR pulses and following Rydberg atom formation in the generated nanoplasma. When a highly-excited Rydberg atom relaxes to its ground state by transferring its excess energy to a weakly bound electron in the environment, electrons with kinetic energies close to the atomic ionization potential are emitted. We show evidence for such an intracluster Coulombic decay process that leaves clear signatures in the electron kinetic energy spectra. ICD is time-resolved in a pump-probe experiment, where a weak probe pulse depopulates the excited states, leading to a quenching of the ICD signal. We find a decay time of 87 ps, which is siginificantly longer than for previous ICD observations, where inner-shell holes were created by XUV pulses. Intracluster Coulombic decay is found to be a generic process that takes places in atomic and molecular clusters and at different wavelengths. It may play an important role in biological systems and in astronomical plasmas. Previous affiliation: Max-Born-Institut, Berlin, Germany.

  12. Quantum simulation of spin models and the discrete Truncated Wigner Approximation: from Rydberg atoms to trapped ions

    NASA Astrophysics Data System (ADS)

    Pineiro Orioli, Asier; Berges, Juergen; Signoles, Adrien; Schempp, Hanna; Whitlock, Shannon; Weidemueller, Matthias; Safavi-Naini, Arghavan; Wall, Michael; Schachenmayer, Johannes; Rey, Ana Maria

    2016-05-01

    Accurate description of the dynamics of quantum spin models is a theoretically challenging problem with widespread applications ranging from condensed matter to high-energy physics. Furthermore recent experimental progress in AMO experiments allows for the physical realization of these models in a variety of setups, such as Rydberg systems and trapped ion experiments, with an unprecedented degree of control and flexibility. Therefore, it is vital to develop efficient theoretical methods capable of simulating the many-body dynamics of such systems. In this work, we employ and extend the recently developed discrete Truncated Wigner Approximation (dTWA), an approximation based on the phase space description of quantum mechanics, to compute the dynamics of two types of spin models: the long-range XY model, which can be realized with Rydberg atoms, and a coupled spin-boson model, which is relevant to trapped ion experiments. Comparisons to experimental results and to available exact solutions to benchmark the method show that the dTWA is capable of capturing important features of the spin evolution and can also help uncovering some underlying non-equilibrium processes.

  13. Precision measurements of ionization and dissociation energies by extrapolation of Rydberg series: from H2 to larger molecules.

    PubMed

    Sprecher, D; Beyer, M; Merkt, F

    2013-01-01

    Recent experiments are reviewed which have led to the determination of the ionization and dissociation energies of molecular hydrogen with a precision of 0.0007 cm(-)1 (8 mJ/mol or 20 MHz) using a procedure based on high-resolution spectroscopic measurements of high Rydberg states and the extrapolation of the Rydberg series to the ionization thresholds. Molecular hydrogen, with only two protons and two electrons, is the simplest molecule with which all aspects of a chemical bond, including electron correlation effects, can be studied. Highly precise values of its ionization and dissociation energies provide stringent tests of the precision of molecular quantum mechanics and of quantum-electrodynamics calculations in molecules. The comparison of experimental and theoretical values for these quantities enable one to quantify the contributions to a chemical bond that are neglected when making the Born-Oppenheimer approximation, i.e. adiabatic, nonadiabatic, relativistic, and radiative corrections. Ionization energies of a broad range of molecules can now be determined experimentally with high accuracy (i.e. about 0.01 cm(-1)). Calculations at similar accuracies are extremely challenging for systems containing more than two electrons. The combination of precision measurements of molecular ionization energies with highly accurateab initio calculations has the potential to provide, in future, fully reliable sets of thermochemical quantities for gas-phase reactions. PMID:23967701

  14. l- and n-changing collisions during interaction of a pulsed beam of Li Rydberg atoms with CO2

    NASA Astrophysics Data System (ADS)

    Dubreuil, B.; Harnafi, M.

    1989-07-01

    The pulsed Li atomic beam produced in our experiment is based on controlled transversely-excited-atmospheric CO2 laser-induced ablation of a Li metal target. The atomic beam is propagated in vacuum or in CO2 gas at low pressure. Atoms in the beam are probed by laser-induced fluorescence spectroscopy. This allows the determination of time-of-flight and velocity distributions. Li Rydberg states (n=5-13) are populated in the beam by two-step pulsed-laser excitation. The excited atoms interact with CO2 molecules. l- and n-changing cross sections are deduced from the time evolution of the resonant or collision-induced fluorescence following this selective excitation. l-changing cross sections of the order of 104 AṦ are measured; they increase with n as opposed to the plateau observed for Li* colliding with a diatomic molecule. This behavior is qualitatively well explained in the framework of the free-electron model. n-->n' changing processes with large cross sections (10-100 AṦ) are also observed even in the case of large electronic energy change (ΔEnn'>103 cm-1). These results can be interpreted in terms of resonant-electronic to vibrational energy transfers between Li Rydberg states and CO2 vibrational modes.

  15. Isotope Shifts and Hyperfine Structure in Calcium 4snp1P1 and 4snf F Rydberg States

    SciTech Connect

    Muller, P.; Bushaw, Bruce A.; Nortershauser, Wilfried; Wendt, K.

    2000-06-01

    Isotope shifts and hyperfine structure have been measured in 4snp 1P1 and 4snf F Rydberg states for all stable calcium isotopes and the radioisotope 41Ca using high-resolution laser spectroscopy. Triple-resonance excitation via 4s2 1S0 --- 4s4p 1P1 --- 4s4d 1D2 --- Rydberg State was followed by photoionization with a CO2 laser and mass selective ion detection. Isotope shifts for the even-mass isotopes have been analyzed to derive specific mass shift and field shift factors. The apparent isotope shifts for 41Ca and 43Ca exhibit anomalous values that are n-dependent. This is interpreted in terms of hyperfine-induced fine structure mixing, which becomes very pronounced when singlet-triplet fine structure splitting is comparable to the hyperfine interaction energy. Measurements of fine structure splittings for the predominant isotope 40Ca have been used as input parameters for theoretical calculation of the perturbed hyperfine structure. Results obtained by diagonalizing the second-order hyperfine interaction matrices agree very well with experimentally observed spectra.

  16. Field-ionization threshold and its induced ionization-window phenomenon for Rydberg atoms in a short single-cycle pulse

    NASA Astrophysics Data System (ADS)

    Yang, B. C.; Robicheaux, F.

    2014-12-01

    We study the field-ionization threshold behavior when a Rydberg atom is ionized by a short single-cycle pulse field. Both hydrogen and sodium atoms are considered. The required threshold field amplitude is found to scale inversely with the binding energy when the pulse duration becomes shorter than the classical Rydberg period, and, thus, more weakly bound electrons require larger fields for ionization. This threshold scaling behavior is confirmed by both three-dimensional classical trajectory Monte Carlo simulations and numerically solving the time-dependent Schrödinger equation. More surprisingly, the same scaling behavior in the short pulse limit is also followed by the ionization thresholds for much lower bound states, including the hydrogen ground state. An empirical formula is obtained from a simple model, and the dominant ionization mechanism is identified as a nonzero spatial displacement of the electron. This displacement ionization should be another important mechanism beyond the tunneling ionization and the multiphoton ionization. In addition, an "ionization window" is shown to exist for the ionization of Rydberg states, which may have potential applications to selectively modify and control the Rydberg-state population of atoms and molecules.

  17. Rydberg series of 1Σu+ and 1Δu states of the Li2 molecule studied by the promotion model

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Jin; Lee, Chun-Woo

    2015-01-01

    We studied the Rydberg series for the 12 1Σu+, 7 1Δu, and 1 1Γu states. This set consists of the seventeen states derivable from the Li(2s) + Li(nl) (n = 2, 3, 4, 5) configuration, one 1Σu+ state and one 1Δu state derivable from Li(2s) + Li(6p) and Li(2s) + Li(6d), respectively, plus one ionic state. We used the multireference configuration interaction method, combined with the Stuttgart/Köln group’s effective core potential/core polarization potential method, to calculate their potential energy curves (PECs). Four Rydberg series, σuns (n = 3, 4, 5, 6), σunp (n = 2, 3, 4, 5), δund (n = 3, 4, 5, 6), and δunf (n = 4, 5), are identified near the potential energy minima (referred to as the ‘Rydberg region’). The promotion model is used to examine the behaviour of PECs and quantum defect curves (QDCs) by constructing diabatic PECs and QDCs. Besides QDCs, effective n and promotion curves are also used to directly examine the promotion. This reveals that the promotion model can be successfully applied to the singlet ungerade states of Li2, indicating that the Rydberg region has the same characteristics as the united atom (UA) limit. Thus, the Rydberg region in Li2 is much closer to the UA limit than the separated atoms (SA) limit. Correlation diagrams based on the promotion model show a big difference in the number of avoided crossings for the 1Σu+ and 1Δu states. The larger number of avoided crossings for 1Σu+ states produces features in the PECs of the 1Σu+ states such as shoulders, flattening, and grouping. The promotion model not only helps to identify Rydberg series, but also to explain all the major and minor aspects and subtle phenomena observed in the PECs and spectroscopic constants of the singlet ungerade Rydberg states of Li2.

  18. Spectroscopy of the NO-Ar Complex in the Vicinity of the 3p← X^2Π Transitions in Nitric Oxide

    NASA Astrophysics Data System (ADS)

    Harris, Joe P.; Wright, Timothy G.; Gardner, Adrian M.; Andrejeva, Anna; Besley, Nicholas A.; Ershova, Olga V.; Klos, Jacek

    2013-06-01

    Spectra of the NO-Ar complex have been recorded using REMPI spectroscopy in the region corresponding to transitions to the 3p Rydberg states in uncomplexed NO. Additionally, spectra have been simulated using ab initio techniques with the aim of better understanding this region, as previous favourable results have been obtained using a similar approach for the 3s Rydberg state. Excellent agreement with the REMPI spectra is seen for the 3p π state simulation. Results on the 3p σ state will be discussed, along with extension to other NO-Rare Gas complexes. J. Klos, M. H. Alexander, R. Hernández-Lamoneda and T. G. Wright J. Chem. Phys., 129, 244303 (2008)

  19. Classical description of charge exchange involving He-like or Li-like ions in Rydberg states in plasmas

    NASA Astrophysics Data System (ADS)

    Kryukov, N.; Oks, E.

    2016-02-01

    A purely classical description of energy terms of one-electron Rydberg quasimolecules (hereafter, RQ1) consisting of one electron and two fully stripped ions of charges Z and Z‧, where Z‧ ≠ Z, had been previously published by one of us. The analysis of the crossings of the energy terms led to a classical description of charge exchange either between a hydrogen-like ion of the nuclear charge Z with a fully stripped ion of the charge Z‧ or between a hydrogen-like ion of the nuclear charge Z‧ with a fully stripped ion of the charge Z. Later applications included, e.g., the influence of electric and magnetic fields, as well as of the screening by plasma electrons. In the present paper we extend the classical description of energy terms to two-electron Rydberg quasimolecules (RQ2), consisting of two electrons and two fully stripped ions of charges Z and Z‧, and to three-electron Rydberg quasimolecules (RQ3), consisting of three electrons and two fully stripped ions of charges Z and Z‧. We show that classical energy terms of RQ2 and RQ3 also exhibit crossings like the energy terms of RQ1. The crossing of terms of RQ2 occurs at a larger internuclear distance compared to the crossing of the corresponding terms of RQ1, so that the cross-section of the charge exchange for RQ2 is larger than the corresponding cross-section for RQ1. The crossing of terms of RQ3 occurs at an even larger internuclear distance compared to the crossing of the corresponding terms of RQ2, so that the cross-section of the charge exchange for RQ3 is even larger than the corresponding cross-section for RQ2. Thus, the classical roots of charge exchange are revealed not only by the example of RQ1 systems, but also by the examples of RQ2 and RQ3 systems. Our results contribute to advance the understanding of the quantum-classical correspondence and can be used in applications where charge exchange plays the key role.

  20. A quantum defect analysis of heavy Rydberg behaviour in the B(u+1Σ) and B″ B ‾ (u+1Σ) states of H2 and the B(u+1Σ) state of D2

    NASA Astrophysics Data System (ADS)

    Lawley, Kenneth P.; Donovan, Robert J.

    2016-08-01

    Heavy Rydberg behaviour in the B(u+1Σ) and B″ B ‾ (u+1Σ) ion-pair states of H2 and the B(u+1Σ) state of D2, is analysed in terms of the absolute quantum defects of the vibronic levels. The influence of the inner repulsive wall of ion-pair potentials on heavy Rydberg behaviour is considered and shown to determine the size of both absolute quantum defects and their energy dependence.