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Sample records for 1d optical lattice

  1. Long distance transport of ultracold atoms using a 1D optical lattice

    NASA Astrophysics Data System (ADS)

    Schmid, Stefan; Thalhammer, Gregor; Winkler, Klaus; Lang, Florian; Hecker Denschlag, Johannes

    2006-08-01

    We study the horizontal transport of ultracold atoms over macroscopic distances of up to 20 cm with a moving 1D optical lattice. By using an optical Bessel beam to form the optical lattice, we can achieve nearly homogeneous trapping conditions over the full transport length, which is crucial in order to hold the atoms against gravity for such a wide range. Fast transport velocities of up to 6 m s-1 (corresponding to about 1100 photon recoils) and accelerations of up to 2600 m s-2 are reached. Even at high velocities the momentum of the atoms is precisely defined with an uncertainty of less than one photon recoil. This allows for construction of an atom catapult with high kinetic energy resolution, which might have applications in novel collision experiments.

  2. Nearest-neighbor detection of atoms in a 1D optical lattice by fluorescence imaging.

    PubMed

    Karski, M; Förster, L; Choi, J M; Alt, W; Widera, A; Meschede, D

    2009-02-06

    We overcome the diffraction limit in fluorescence imaging of neutral atoms in a sparsely filled one-dimensional optical lattice. At a periodicity of 433 nm, we reliably infer the separation of two atoms down to nearest neighbors. We observe light induced losses of atoms occupying the same lattice site, while for atoms in adjacent lattice sites, no losses due to light induced interactions occur. Our method points towards characterization of correlated quantum states in optical lattice systems with filling factors of up to one atom per lattice site.

  3. A technique for individual atom delivery into a crossed vortex bottle beam trap using a dynamic 1D optical lattice.

    PubMed

    Dinardo, Brad A; Anderson, Dana Z

    2016-12-01

    We describe a system for loading a single atom from a reservoir into a blue-detuned crossed vortex bottle beam trap using a dynamic 1D optical lattice. The lattice beams are frequency chirped using acousto-optic modulators, which causes the lattice to move along its axial direction and behave like an optical conveyor belt. A stationary lattice is initially loaded with approximately 6000 atoms from a reservoir, and the conveyor belt transports them 1.1 mm from the reservoir to a bottle beam trap, where a single atom is loaded via light-assisted collisions. Photon counting data confirm that an atom can be delivered and loaded into the bottle beam trap 13.1% of the time.

  4. A technique for individual atom delivery into a crossed vortex bottle beam trap using a dynamic 1D optical lattice

    NASA Astrophysics Data System (ADS)

    Dinardo, Brad A.; Anderson, Dana Z.

    2016-12-01

    We describe a system for loading a single atom from a reservoir into a blue-detuned crossed vortex bottle beam trap using a dynamic 1D optical lattice. The lattice beams are frequency chirped using acousto-optic modulators, which causes the lattice to move along its axial direction and behave like an optical conveyor belt. A stationary lattice is initially loaded with approximately 6000 atoms from a reservoir, and the conveyor belt transports them 1.1 mm from the reservoir to a bottle beam trap, where a single atom is loaded via light-assisted collisions. Photon counting data confirm that an atom can be delivered and loaded into the bottle beam trap 13.1% of the time.

  5. Collective Excitations of a Trapped Bose-Einstein Condensate in the Presence of a 1D Optical Lattice

    NASA Astrophysics Data System (ADS)

    Fort, C.; Cataliotti, F. S.; Fallani, L.; Ferlaino, F.; Maddaloni, P.; Inguscio, M.

    2003-04-01

    We study low-lying collective modes of an elongated 87Rb condensate produced in a 3D magnetic harmonic trap with the addition of a 1D periodic potential which is provided by a laser standing wave along the axial direction. While the transverse breathing mode remains unperturbed, quadrupole and dipole oscillations along the optical lattice are strongly modified. Precise measurements of the collective mode frequencies at different heights of the optical barriers provide a stringent test of the theoretical model recently introduced [

    M. Krämer et al., Phys. Rev. Lett.PRLTAO0031-9007 88, 180404 (2002)
    ].

  6. Phase diagram of 1D spin-orbit coupled Fermi gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Qu, Chunlei; Gong, Ming; Zhang, Chuanwei

    2013-03-01

    We consider a one dimensional spin-orbit coupled Fermi gas in optical lattices with open boundary condition. This system belongs to the BDI symmetry class because the Hamiltonian can be made real when the Zeeman field is assumed to be along the z direction, thus the topological superfluid is characterized by Z, instead of Z2 class. In the optical lattice system, each site admits at most two fermions. The system can host plenty of phases depending on the filling factor and the Zeeman field. At finite Zeeman field we observe a strong competition between the topological superfluid phase and the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase. The latter phase is more likely to be observed near the half filling. The spin-orbit coupling plays the role of enhancing the topological superfluid phase and suppressing the FFLO phase, which the Hartree shift plays an utterly opposite role. The possible observation of topological phase is also discussed in the presence of a harmonic trap. This work is supported by ARO, AFOSR, and NSF

  7. Helical Floquet Channels in 1D Lattices

    NASA Astrophysics Data System (ADS)

    Budich, Jan Carl; Hu, Ying; Zoller, Peter

    2017-03-01

    We show how dispersionless channels exhibiting perfect spin-momentum locking can arise in a 1D lattice model. While such spectra are forbidden by fermion doubling in static 1D systems, here we demonstrate their appearance in the stroboscopic dynamics of a periodically driven system. Remarkably, this phenomenon does not rely on any adiabatic assumptions, in contrast to the well known Thouless pump and related models of adiabatic spin pumps. The proposed setup is shown to be experimentally feasible with state-of-the-art techniques used to control ultracold alkaline earth atoms in optical lattices.

  8. Scratched-XY Universality and Phase Diagram of Disordered 1D Bosons in Optical Lattice

    NASA Astrophysics Data System (ADS)

    Yao, Zhiyuan; Pollet, Lode; Prokof'ev, Nikolay; Svistunov, Boris

    The superfluid-insulator quantum phase transition in a 1D system with weak links belongs to the so-called scratched-XY universality class, provided the irrenormalizable exponent ζ characterizing the distribution of weak links is smaller than 2 / 3 . With a combination of worm-algorithm Monte Carlo simulations and asymptotically exact analytics, we accurately trace the position of the scratched-XY critical line on the ground-state phase diagram of bosonic Hubbard model at unity filling. In particular, we reveal the location of the tricritical point separating the scratched-XY criticality from the Giamarchi-Schulz one.

  9. Quantum signature of breathers in 1D ultracold bosons in optical lattices involving next-nearest neighbor interactions

    NASA Astrophysics Data System (ADS)

    Djoufack, Z. I.; Kenfack-Jiotsa, A.; Nguenang, J.-P.

    2017-08-01

    The dynamics and the energy spectrum of an ultracold gas of bosonic atoms in an optical lattice can be described by a Bose-Hubbard model for which the system parameters can be controlled by laser light. We study by means of the perturbation theory in addition to the numerical diagonalization, the energy spectrum and the related features of the band structures of the ultracold bosons in optical lattices containing a few number of quanta interacting with next-nearest neighbor interactions (NNNI) modeled by the Bose-Hubbard Hamiltonian. The energy spectra of such system display the bound states signature, which are analyzed in the first Brillouin zone for different wave numbers. The finding, i.e., quantum breathers, shows that their probabilities’ weight depends on the wave vector. The influence of NNNI on both the probabilities’ amplitude and the correlation function is also realized in case of a system with a small number of sites, respectively.

  10. Quasi steady-states, spin statistics, and interaction-induced transport of ultra-cold atoms in 1D optical lattices

    NASA Astrophysics Data System (ADS)

    Chien, Chih-Chun; Zwolak, Michael; di Ventra, Massimiliano

    2012-02-01

    We consider several non-equilibrium scenarios where ultra-cold atoms are initially loaded into the ground state of a 1D optical lattice. The system is then set out of equilibrium either by inducing a density imbalance or by imposing time-dependent inhomogeneous interactions. To monitor the dynamics, we have implemented the micro-canonical approach to transport [1] which has been previously used to study electron dynamics in nanoscale systems. We have found that by removing particles on the right half of the lattice, fermions form a quasi steady-state current, which can be observed as a plateau in the current as a function of time. In contrast, the bosonic current oscillates and decays to zero in the thermodynamic limit [2]. The difference appears in uniform lattices as well as lattices with a harmonic trap. Further, when light-induced interactions are applied to half of the lattice, we have found, using a Hartree-Fock approximation, a conducting-nonconducting transition in the fermionic case as the interaction increases. Our studies are relevant to recent experiments on transport of ultra-cold atoms and address fundamental issues in nanoscale electronic transport. [4pt] [1] Di Ventra and Todorov,J. Phys. Cond. Matt. 16, 8025 (2004).[0pt] [2] Chien, Zwolak, Di Ventra, arXiv: 1110.1646.

  11. Detecting π-phase superfluids with p-wave symmetry in a quasi-1D optical lattice

    NASA Astrophysics Data System (ADS)

    Liu, Bo; Li, Xiaopeng; Hulet, Randall G.; Liu, W. Vincent

    2016-05-01

    We propose an experimental protocol to create a p-wave superfluid in a spin-polarized cold Fermi gas tuned by an s-wave Feshbach resonance. A crucial ingredient is to add an anisotropic 3D optical lattice and tune the fillings of two spins to the s and p band, respectively. The pairing order parameter is confirmed to inherit p-wave symmetry in its center-of-mass motion. We find that it can further develop into a state of unexpected π-phase modulation in a broad parameter regime. Experimental signatures are predicted in the momentum distributions, density of states and spatial densities for a realistic experimental setup. The π-phase p-wave superfluid is reminiscent of the π-state in superconductor-ferromagnet heterostructures but differs in symmetry and physical origin. The spatially-varying phases of the superfluid gap provide a novel approach to synthetic magnetic fields for neutral atoms. It would represent another example of p-wave pairing, first discovered in He-3 liquids. Work supported in part by U.S. ARO, AFOSR, NSF, ONR, Charles E. Kaufman Foundation, and The Pittsburgh Foundation, LPS-MPO-CMTC, JQI-NSF-PFC, ARO-Atomtronics-MURI, the Welch Foundation, ARO-MURI and NSF of China.

  12. Effect of the band structure in a rigorous two-body model with long-range interactions in 1D optical lattices

    NASA Astrophysics Data System (ADS)

    Kristensen, Tom; Simoni, Andrea; Launay, Jean-Michel

    2016-05-01

    We compute scattering and bound state properties for two ultracold molecules in a pure 1D optical lattice. We introduce reference functions with complex quasi-momentum that naturally account for the effect of excited energy bands. Our exact results for a short-range interaction are first compared with the simplest version of the standard Bose-Hubbard (BH) model. Such comparison allows us to highlight the effect of the excited bands, of the non-on-site interaction and of tunneling with distant neighbor, that are not taken into account in the BH model. The effective interaction can depend strongly on the particle quasi-momenta and can present a resonant behavior even in a deep lattice. As a second step, we study scattering of two polar particles in the optical lattice. Peculiar Wigner threshold laws stem from the interplay of the long range dipolar interaction and the presence of the energy bands. We finally assess the validity of an extended Bose-Hubbard model for dipolar gases based on our exact two-body calculations. This work was supported by the Agence Nationale de la Recherche (Contract No. ANR-12-BS04-0020-01).

  13. Transport of a Bose gas in 1D disordered lattices at the fluid-insulator transition.

    PubMed

    Tanzi, Luca; Lucioni, Eleonora; Chaudhuri, Saptarishi; Gori, Lorenzo; Kumar, Avinash; D'Errico, Chiara; Inguscio, Massimo; Modugno, Giovanni

    2013-09-13

    We investigate the momentum-dependent transport of 1D quasicondensates in quasiperiodic optical lattices. We observe a sharp crossover from a weakly dissipative regime to a strongly unstable one at a disorder-dependent critical momentum. In the limit of nondisordered lattices the observations suggest a contribution of quantum phase slips to the dissipation. We identify a set of critical disorder and interaction strengths for which such critical momentum vanishes, separating a fluid regime from an insulating one. We relate our observation to the predicted zero-temperature superfluid-Bose glass transition.

  14. Optical Lattice Clocks

    NASA Astrophysics Data System (ADS)

    Oates, Chris

    2012-06-01

    Since they were first proposed in 2003 [1], optical lattice clocks have become one of the leading technologies for the next generation of atomic clocks, which will be used for advanced timing applications and in tests of fundamental physics [2]. These clocks are based on stabilized lasers whose frequency is ultimately referenced to an ultra-narrow neutral atom transition (natural linewidths << 1 Hz). To suppress the effects of atomic motion/recoil, the atoms in the sample (˜10^4 atoms) are confined tightly in the potential wells of an optical standing wave (lattice). The wavelength of the lattice light is tuned to its ``magic'' value so as to yield a vanishing net AC Stark shift for the clock transition. As a result lattice clocks have demonstrated the capability of generating high stability clock signals with small absolute uncertainties (˜ 1 part in 10^16). In this presentation I will first give an overview of the field, which now includes three different atomic species. I will then use experiments with Yb performed in our laboratory to illustrate the key features of a lattice clock. Our research has included the development of state-of-the-art optical cavities enabling ultra-high-resolution optical spectroscopy (1 Hz linewidth). Together with the large atom number in the optical lattice, we are able to achieve very low clock instability (< 0.3 Hz in 1 s) [3]. Furthermore, I will show results from some of our recent investigations of key shifts for the Yb lattice clock, including high precision measurements of ultracold atom-atom interactions in the lattice and the dc Stark effect for the Yb clock transition (necessary for the evaluation of blackbody radiation shifts). [4pt] [1] H. Katori, M. Takamoto, V. G. Pal'chikov, and V. D. Ovsiannikov, Phys. Rev. Lett. 91, 173005 (2003). [0pt] [2] Andrei Derevianko and Hidetoshi Katori, Rev. Mod. Phys. 83, 331 (2011). [0pt] [3] Y. Y. Jiang, A. D. Ludlow, N. D. Lemke, R. W. Fox, J. A. Sherman, L.-S. Ma, and C. W. Oates

  15. Fibonacci Optical Lattices

    NASA Astrophysics Data System (ADS)

    Singh, Kevin; Geiger, Zachary; Senaratne, Ruwan; Rajagopal, Shankari; Fujiwara, Kurt; Weld, David; Weld Group Team

    2015-05-01

    Quasiperiodicity is intimately involved in quantum phenomena from localization to the quantum Hall effect. Recent experimental investigation of quasiperiodic quantum effects in photonic and electronic systems have revealed intriguing connections to topological phenomena. However, such experiments have been limited by the absence of techniques for creating tunable quasiperiodic structures. We propose a new type of quasiperiodic optical lattice, constructed by intersecting a Gaussian beam with a 2D square lattice at an angle with an irrational tangent. The resulting potential, a generalization of the Fibonacci lattice, is a physical realization of the mathematical ``cut-and-project'' construction which underlies all quasiperiodic structures. Calculation of the energies and wavefunctions of atoms loaded into the proposed quasiperiodic lattice demonstrate a fractal energy spectrum and the existence of edge states. We acknowledge support from the ONR (award N00014-14-1-0805), the ARO and the PECASE program (award W911NF-14-1-0154), the AFOSR (award FA9550-12-1-0305), and the Alfred P. Sloan foundation (grant BR2013-110).

  16. Statistical Transmutation in Floquet Driven Optical Lattices.

    PubMed

    Sedrakyan, Tigran A; Galitski, Victor M; Kamenev, Alex

    2015-11-06

    We show that interacting bosons in a periodically driven two dimensional (2D) optical lattice may effectively exhibit fermionic statistics. The phenomenon is similar to the celebrated Tonks-Girardeau regime in 1D. The Floquet band of a driven lattice develops the moat shape, i.e., a minimum along a closed contour in the Brillouin zone. Such degeneracy of the kinetic energy favors fermionic quasiparticles. The statistical transmutation is achieved by the Chern-Simons flux attachment similar to the fractional quantum Hall case. We show that the velocity distribution of the released bosons is a sensitive probe of the fermionic nature of their stationary Floquet state.

  17. Tensor network simulation of QED on infinite lattices: Learning from (1 +1 ) d , and prospects for (2 +1 ) d

    NASA Astrophysics Data System (ADS)

    Zapp, Kai; Orús, Román

    2017-06-01

    The simulation of lattice gauge theories with tensor network (TN) methods is becoming increasingly fruitful. The vision is that such methods will, eventually, be used to simulate theories in (3 +1 ) dimensions in regimes difficult for other methods. So far, however, TN methods have mostly simulated lattice gauge theories in (1 +1 ) dimensions. The aim of this paper is to explore the simulation of quantum electrodynamics (QED) on infinite lattices with TNs, i.e., fermionic matter fields coupled to a U (1 ) gauge field, directly in the thermodynamic limit. With this idea in mind we first consider a gauge-invariant infinite density matrix renormalization group simulation of the Schwinger model—i.e., QED in (1 +1 ) d . After giving a precise description of the numerical method, we benchmark our simulations by computing the subtracted chiral condensate in the continuum, in good agreement with other approaches. Our simulations of the Schwinger model allow us to build intuition about how a simulation should proceed in (2 +1 ) dimensions. Based on this, we propose a variational ansatz using infinite projected entangled pair states (PEPS) to describe the ground state of (2 +1 ) d QED. The ansatz includes U (1 ) gauge symmetry at the level of the tensors, as well as fermionic (matter) and bosonic (gauge) degrees of freedom both at the physical and virtual levels. We argue that all the necessary ingredients for the simulation of (2 +1 ) d QED are, a priori, already in place, paving the way for future upcoming results.

  18. Optical Abelian lattice gauge theories

    SciTech Connect

    Tagliacozzo, L.; Celi, A.; Zamora, A.; Lewenstein, M.

    2013-03-15

    We discuss a general framework for the realization of a family of Abelian lattice gauge theories, i.e., link models or gauge magnets, in optical lattices. We analyze the properties of these models that make them suitable for quantum simulations. Within this class, we study in detail the phases of a U(1)-invariant lattice gauge theory in 2+1 dimensions, originally proposed by P. Orland. By using exact diagonalization, we extract the low-energy states for small lattices, up to 4 Multiplication-Sign 4. We confirm that the model has two phases, with the confined entangled one characterized by strings wrapping around the whole lattice. We explain how to study larger lattices by using either tensor network techniques or digital quantum simulations with Rydberg atoms loaded in optical lattices, where we discuss in detail a protocol for the preparation of the ground-state. We propose two key experimental tests that can be used as smoking gun of the proper implementation of a gauge theory in optical lattices. These tests consist in verifying the absence of spontaneous (gauge) symmetry breaking of the ground-state and the presence of charge confinement. We also comment on the relation between standard compact U(1) lattice gauge theory and the model considered in this paper. - Highlights: Black-Right-Pointing-Pointer We study the quantum simulation of dynamical gauge theories in optical lattices. Black-Right-Pointing-Pointer We focus on digital simulation of abelian lattice gauge theory. Black-Right-Pointing-Pointer We rediscover and discuss the puzzling phase diagram of gauge magnets. Black-Right-Pointing-Pointer We detail the protocol for time evolution and ground-state preparation in any phase. Black-Right-Pointing-Pointer We provide two experimental tests to validate gauge theory quantum simulators.

  19. A transportable optical lattice clock

    NASA Astrophysics Data System (ADS)

    Vogt, Stefan; Häfner, Sebastian; Grotti, Jacopo; Koller, Silvio; Al-Masoudi, Ali; Sterr, Uwe; Lisdat, Christian

    2016-06-01

    We present the experimental setup and first results of PTB's transportable 87Sr clock. It consists of a physics package, several compact laser breadboards, and a transportable high finesse cavity for the clock laser. A comparison of the transportable system with our stationary optical lattice clock yields an instability of 2.2 x 10-15 √s/τ for the transportable clock. The current fractional uncertainty of 1 × 10-15 is still limited by the not yet fully evaluated light shift from the free running optical lattice laser operated near the magic wavelength. We are currently improving our transportable system to reach an uncertainty at or below the 10-17 level, which will finaly be limited by the uncertainty in blackbody radiation shift correction.

  20. Subwavelength lattice optics by evolutionary design.

    PubMed

    Huntington, Mark D; Lauhon, Lincoln J; Odom, Teri W

    2014-12-10

    This paper describes a new class of structured optical materials--lattice opto-materials--that can manipulate the flow of visible light into a wide range of three-dimensional profiles using evolutionary design principles. Lattice opto-materials are based on the discretization of a surface into a two-dimensional (2D) subwavelength lattice whose individual lattice sites can be controlled to achieve a programmed optical response. To access a desired optical property, we designed a lattice evolutionary algorithm that includes and optimizes contributions from every element in the lattice. Lattice opto-materials can exhibit simple properties, such as on- and off-axis focusing, and can also concentrate light into multiple, discrete spots. We expanded the unit cell shapes of the lattice to achieve distinct, polarization-dependent optical responses from the same 2D patterned substrate. Finally, these lattice opto-materials can also be combined into architectures that resemble a new type of compound flat lens.

  1. Hybrid multisite excitations in dipolar condensates in optical lattices

    SciTech Connect

    Klawunn, M.; Santos, L.

    2009-07-15

    Strong one-dimensional (1D) lattices usually lead to unconnected two-dimensional gases. The long-range character of the dipole-dipole interactions leads to a scenario where nonoverlapping gases at different sites may interact significantly. We show that the excitations of nonoverlapping condensates in 1D optical lattices acquire a bandlike character, being collectively shared by different sites. In particular, the hybridization of the modes significantly enhances the rotonization of the excitations and may induce roton instability. We discuss the observability of this effect in ongoing experiments.

  2. Unity Occupation of Sites in a 3D Optical Lattice

    NASA Astrophysics Data System (ADS)

    Depue, Marshall T.; McCormick, Colin; Winoto, S. Lukman; Oliver, Steven; Weiss, David S.

    1999-03-01

    An average filling factor of one atom per lattice site has been obtained in a submicron scale far-off-resonance optical lattice (FORL). High site occupation is obtained through a compression sequence that includes laser cooling in a 3D FORL and adiabatic toggling between the 3D FORL and a 1D FORL trap. After the highest filling factor is achieved, laser cooling causes collisional loss from lattice sites with more than one atom. Ultimately 44% of the sites have a single atom cooled to near its vibrational ground state. A theoretical model of site occupation based on Poisson statistics agrees well with the experimental results.

  3. Experimental generation of optical coherence lattices

    SciTech Connect

    Chen, Yahong; Cai, Yangjian E-mail: yangjiancai@suda.edu.cn; Ponomarenko, Sergey A. E-mail: yangjiancai@suda.edu.cn

    2016-08-08

    We report experimental generation and measurement of recently introduced optical coherence lattices. The presented optical coherence lattice realization technique hinges on a superposition of mutually uncorrelated partially coherent Schell-model beams with tailored coherence properties. We show theoretically that information can be encoded into and, in principle, recovered from the lattice degree of coherence. Our results can find applications to image transmission and optical encryption.

  4. Lattice-induced nonadiabatic frequency shifts in optical lattice clocks

    SciTech Connect

    Beloy, K.

    2010-09-15

    We consider the frequency shift in optical lattice clocks which arises from the coupling of the electronic motion to the atomic motion within the lattice. For the simplest of three-dimensional lattice geometries this coupling is shown to affect only clocks based on blue-detuned lattices. We have estimated the size of this shift for the prospective strontium lattice clock operating at the 390-nm blue-detuned magic wavelength. The resulting fractional frequency shift is found to be on the order of 10{sup -18} and is largely overshadowed by the electric quadrupole shift. For lattice clocks based on more complex geometries or other atomic systems, this shift could potentially be a limiting factor in clock accuracy.

  5. Realizing Parafermions in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Liu, Fangli; Gorshkov, Alexey

    2016-05-01

    Parafermions, which are the fractional versions of Majorana fermions, possess more exotic braiding statistics than Majorana fermions and are therefore more powerful from the point of view of topological quantum computing. We propose a scheme to realize parafermionic zero modes in optical lattices, without the use of superconductive paring. With the help of laser assisted tunneling and on-site interactions, two layers of ultracold atoms in distinct hyperfine states can be engineered to host +/- 1 / m fractional quantum Hall states. We then introduce a finite-extent potential barrier that pierces both layers - this gives rise to two counter-propagating edge states that sit on top of each other. Finally, laser induced coupling is used to introduce backscattering between the two edge states and to gap them out. We show that the resulting defects give rise to the topological degeneracy associated with parafermions. We also discuss methods for preparation and detection.

  6. 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.

  7. A Deconstruction Lattice Description of the D1/D5 Brane World-Volume Gauge Theory

    DOE PAGES

    Giedt, Joel

    2011-01-01

    I genermore » alize the deconstruction lattice formulation of Endres and Kaplan to two-dimensional super-QCD with eight supercharges, denoted by (4,4), and bifundamental matter. I specialize to a particularly interesting (4,4) gauge theory, with gauge group U ( N c ) × U ( N f ) , and U ( N f ) being weakly gauged. It describes the infrared limit of the D1/D5 brane system, which has been studied extensively as an example of the AdS 3 /CFT 2 correspondence. The construction here preserves two supercharges exactly and has a lattice structure quite similar to that which has previously appeared in the deconstruction approach, that is, site, link, and diagonal fields with both the Bose and Fermi statistics. I remark on possible applications of the lattice theory that would test the AdS 3 /CFT 2 correspondence, particularly one that would exploit the recent worldsheet instanton analysis of Chen and Tong.« less

  8. Fixed-node Monte Carlo calculations for the 1d Kondo lattice model

    NASA Astrophysics Data System (ADS)

    Bemmel, H. J. M. van; Saarloos, W. van; Haaf, D. F. B. ten

    The effectiveness of the recently developed Fixed-Node Quantum Monte Carlo method for lattice fermions, developed by van Leeuwen and co-workers, is tested by applying it to the 1d Kondo lattice, an example of a one-dimensional model with a sign problem. The principles of this method and its implementation for the Kondo lattice model are discussed in detail. We compare the fixed-node upper bound for the ground-state energy at half filling with exact-diagonalization results from the literature, and determine several spin correlation functions. Our ‘best estimates’ for the ground-state correlation functions do not depend sensitively on the input trial wave function of the fixed-node projection, and are reasonably close to the exact values. We also calculate the spin gap of the model with the Fixed-Node Monte Carlo method. For this it is necessary to use a many-Slater-determinant trial state. The lowest-energy spin excitation is a running spin soliton with wave number π, in agreement with earlier calculations.

  9. Optical Lattice Gases of Interacting Fermions

    DTIC Science & Technology

    2015-12-02

    Communications, including a review paper on the orbital physics of cold atoms in optical lattices [1] and a book chapter on topological insulators of cold...from the early years of particle physics and quantum field theory. 4. New edge modes in periodically driven cold atoms on optical lattice. The...New Trends in Atomic and Molecular Physics , edited by M. Mohan, Springer Series on Atomic , Optical, and Plasma Physics Vol. 76, 201 (2013). 15

  10. Subwavelength Lattice Optics by Evolutionary Design

    PubMed Central

    2015-01-01

    This paper describes a new class of structured optical materials—lattice opto-materials—that can manipulate the flow of visible light into a wide range of three-dimensional profiles using evolutionary design principles. Lattice opto-materials are based on the discretization of a surface into a two-dimensional (2D) subwavelength lattice whose individual lattice sites can be controlled to achieve a programmed optical response. To access a desired optical property, we designed a lattice evolutionary algorithm that includes and optimizes contributions from every element in the lattice. Lattice opto-materials can exhibit simple properties, such as on- and off-axis focusing, and can also concentrate light into multiple, discrete spots. We expanded the unit cell shapes of the lattice to achieve distinct, polarization-dependent optical responses from the same 2D patterned substrate. Finally, these lattice opto-materials can also be combined into architectures that resemble a new type of compound flat lens. PMID:25380062

  11. Optical lattice on an atom chip.

    PubMed

    Gallego, D; Hofferberth, S; Schumm, T; Krüger, P; Schmiedmayer, J

    2009-11-15

    Optical dipole traps and atom chips are two very powerful tools for the quantum manipulation of neutral atoms. We demonstrate that both methods can be combined by creating an optical lattice potential on an atom chip. A red-detuned laser beam is retroreflected using the atom chip surface as a high-quality mirror, generating a vertical array of purely optical oblate traps. We transfer thermal atoms from the chip into the lattice and observe cooling into the two-dimensional regime. Using a chip-generated Bose-Einstein condensate, we demonstrate coherent Bloch oscillations in the lattice.

  12. Dynamics of matter waves in tailored optical and atomic lattices

    NASA Astrophysics Data System (ADS)

    Reeves, Jeremy; Gadway, Bryce; Krinner, Ludwig; Pertot, Daniel; Vogt, Matthias; Schneble, Dominik

    2012-06-01

    We report experimental results on the dynamics of atomic matter waves in temporally and spatially modulated lattices. In a first experiment, we investigated the effects of disorder on dynamical localization in a periodically-pulsed optical lattice in the framework of a kicked-rotor model. A second experiment explored the interplay between disorder and interactions in the damping of Bloch oscillations in a tilted disordered lattice. In a third experiment, we examined the diffraction of atomic matter waves from 1D ``crystal'' arrays of lattice-trapped atoms with respect to the temporal dynamics of matter-wave scattering. We also demonstrated the use of matter waves to detect forced antiferromagnetic ordering in an atomic spin-mixture.

  13. Anyonic braiding in optical lattices

    PubMed Central

    Zhang, Chuanwei; Scarola, V. W.; Tewari, Sumanta; Das Sarma, S.

    2007-01-01

    Topological quantum states of matter, both Abelian and non-Abelian, are characterized by excitations whose wavefunctions undergo nontrivial statistical transformations as one excitation is moved (braided) around another. Topological quantum computation proposes to use the topological protection and the braiding statistics of a non-Abelian topological state to perform quantum computation. The enormous technological prospect of topological quantum computation provides new motivation for experimentally observing a topological state. Here, we explicitly work out a realistic experimental scheme to create and braid the Abelian topological excitations in the Kitaev model built on a tunable robust system, a cold atom optical lattice. We also demonstrate how to detect the key feature of these excitations: their braiding statistics. Observation of this statistics would directly establish the existence of anyons, quantum particles that are neither fermions nor bosons. In addition to establishing topological matter, the experimental scheme we develop here can also be adapted to a non-Abelian topological state, supported by the same Kitaev model but in a different parameter regime, to eventually build topologically protected quantum gates. PMID:18000038

  14. Cold atoms in a rotating optical lattice

    NASA Astrophysics Data System (ADS)

    Foot, Christopher J.

    2009-05-01

    We have demonstrated a novel experimental arrangement which can rotate a two-dimensional optical lattice at frequencies up to several kilohertz. Our arrangement also allows the periodicity of the optical lattice to be varied dynamically, producing a 2D ``accordion lattice'' [1]. The angles of the laser beams are controlled by acousto-optic deflectors and this allows smooth changes with little heating of the trapped cold (rubidium) atoms. We have loaded a BEC into lattices with periodicities ranging from 1.8μm to 18μm, observing the collapse and revival of the diffraction orders of the condensate over a large range of lattice parameters as recently reported by a group in NIST [2]. We have also imaged atoms in situ in a 2D lattice over a range of lattice periodicities. Ultracold atoms in a rotating lattice can be used for the direct quantum simulation of strongly correlated systems under large effective magnetic fields, i.e. the Hamiltonian of the atoms in the rotating frame resembles that of a charged particle in a strong magnetic field. In the future, we plan to use this to investigate a range of phenomena such as the analogue of the fractional quantum Hall effect. [4pt] [1] R. A. Williams, J. D. Pillet, S. Al-Assam, B. Fletcher, M. Shotter, and C. J. Foot, ``Dynamic optical lattices: two-dimensional rotating and accordion lattices for ultracold atoms,'' Opt. Express 16, 16977-16983 (2008) [0pt] [2] J. H. Huckans, I. B. Spielman, B. Laburthe Tolra, W. D. Phillips, and J. V. Porto, Quantum and Classical Dynamics of a BEC in a Large-Period Optical Lattice, arXiv:0901.1386v1

  15. Critical and multicritical semi-random (1 + d)-dimensional lattices and hard objects in d dimensions

    NASA Astrophysics Data System (ADS)

    Di Francesco, P.; Guitter, E.

    2002-02-01

    We investigate models of (1 + d)D Lorentzian semi-random lattices with one random (space-like) direction and d regular (time-like) ones. We prove a general inversion formula expressing the partition function of these models as the inverse of that of hard objects in d dimensions. This allows for an exact solution of a variety of new models including critical and multicritical generalized (1+1)D Lorentzian surfaces, with fractal dimensions dF = k + 1, k = 1,2,3,... , as well as a new model of (1+2)D critical tetrahedral complexes, with fractal dimension dF = 12/5. Critical exponents and universal scaling functions follow from this solution. We finally establish a general connection between (1 + d)D Lorentzian lattices and directed-site lattice animals in (1 + d) dimensions.

  16. Exact solutions for 1D lattice models with topological complicated configuration

    NASA Astrophysics Data System (ADS)

    Fang, Lei; Schmeltzer, David

    In this work a transfer matrix method is developed to study 1D lattice models within the tight binding framework. Employing this method we show, from simple to difficult, the solutions of a semi-infinite wire, a finite open wire, a single closed ring and two coupled rings. We start by studying local properties of solutions in a homogeneous region. It is found that a calculation of the exponential of the transfer matrix is necessary for us to obtain the general form of wave functions in the entire homogenous region. Then by matching wave functions at boundaries or connecting junctions we can get equations that determine the spectrum. In this way we have solved the problem of two coupled rings (a topologically complicated configuration) and it is shown there can exist bound state in this system. This work was supported in part by the U.S. DOE O?ce of Basic Energy Sciences (Program Code: E304).

  17. 1-D ELECTRO-OPTIC BEAM STEERING DEVICE.

    PubMed

    Wang, Wei-Chih; Tsui, Chi Leung

    2011-06-05

    In this paper, we present the design and fabrication of a 1D beam steering device based on planar electro-optic thermal-plastic prisms and a collimator lens array. With the elimination of moving parts, the proposed device is able to overcome the mechanical limitations of present scanning devices, such as fatigue and low operating frequency, while maintaining a small system footprint (~0.5mm×0.5mm). From experimental data, our prototype device is able to achieve a maximum deflection angle of 5.6° for a single stage prism design and 29.2° for a cascaded three prisms stage design. The lens array shows a 4µm collimated beam diameter.

  18. 1-D ELECTRO-OPTIC BEAM STEERING DEVICE

    PubMed Central

    Wang, Wei-Chih; Tsui, Chi Leung

    2011-01-01

    In this paper, we present the design and fabrication of a 1D beam steering device based on planar electro-optic thermal-plastic prisms and a collimator lens array. With the elimination of moving parts, the proposed device is able to overcome the mechanical limitations of present scanning devices, such as fatigue and low operating frequency, while maintaining a small system footprint (~0.5mm×0.5mm). From experimental data, our prototype device is able to achieve a maximum deflection angle of 5.6° for a single stage prism design and 29.2° for a cascaded three prisms stage design. The lens array shows a 4µm collimated beam diameter. PMID:22199458

  19. Spin-orbit coupling in a strontium optical lattice clock

    NASA Astrophysics Data System (ADS)

    Bothwell, Tobias; Bromley, Sarah; Kolkowitz, Shimon; Zhang, Xibo; Wall, Michael; Rey, Ana Maria; Ye, Jun

    2016-05-01

    Synthetic gauge fields are a promising tool for creating complex Hamiltonians with ultracold neutral atoms that may mimic the fractional Quantum Hall effect and other topological states. A promising approach is to use spin-orbit coupling to treat an internal degree of freedom as an effective `synthetic' spatial dimension. Here, this synthetic dimension is comprised by the internal ground and excited states used for high-precision clock spectroscopy in a fermionic strontium optical lattice clock. We report on our progress towards this goal in a system where atoms tunnel through a 1D optical lattice during clock interrogation. We present measurements of the lattice band structure under varying Lamb-Dicke parameters and in a regime where s-wave collisions are expected to contribute density dependent frequency shifts.

  20. Direct Tunneling Delay Time Measurement in an Optical Lattice

    NASA Astrophysics Data System (ADS)

    Fortun, A.; Cabrera-Gutiérrez, C.; Condon, G.; Michon, E.; Billy, J.; Guéry-Odelin, D.

    2016-07-01

    We report on the measurement of the time required for a wave packet to tunnel through the potential barriers of an optical lattice. The experiment is carried out by loading adiabatically a Bose-Einstein condensate into a 1D optical lattice. A sudden displacement of the lattice by a few tens of nanometers excites the micromotion of the dipole mode. We then directly observe in momentum space the splitting of the wave packet at the turning points and measure the delay between the reflected and the tunneled packets for various initial displacements. Using this atomic beam splitter twice, we realize a chain of coherent micron-size Mach-Zehnder interferometers at the exit of which we get essentially a wave packet with a negative momentum, a result opposite to the prediction of classical physics.

  1. Optical physics: Magnetic appeal in strained lattice

    NASA Astrophysics Data System (ADS)

    Lepetit, Thomas

    2013-02-01

    Using strain to induce a pseudomagnetic field in a photonic lattice at optical frequencies might bring improvements to fields such as photonic crystal fibres, supercontinuum generation and frequency combs.

  2. Photonic spectrum of bichromatic optical lattices

    SciTech Connect

    Rist, Stefan; Morigi, Giovanna; Vignolo, Patrizia

    2009-05-15

    We study the photonic spectrum of a one-dimensional optical lattice possessing a double primitive cell, when the atoms are well localized at the lattice minima. While a one-dimensional lattice with a simple Wigner-Seitz cell always possesses a photonic band gap at the atomic resonance, in this configuration the photonic transmission spectrum may exhibit no, double, or multiple photonic band gaps depending on the ratio between the interparticle distance {rho} inside the cell and the cell size a. The transmission spectra of a weak incident probe are evaluated when the atoms are trapped in free space and inside an optical resonator for realistic experimental parameters.

  3. Colloquium: Physics of optical lattice clocks

    NASA Astrophysics Data System (ADS)

    Derevianko, Andrei; Katori, Hidetoshi

    2011-04-01

    Recently invented and demonstrated optical lattice clocks hold great promise for improving the precision of modern time keeping. These clocks aim at the 10-18 fractional accuracy, which translates into a clock that would neither lose nor gain a fraction of a second over an estimated age of the Universe. In these clocks, millions of atoms are trapped and interrogated simultaneously, dramatically improving clock stability. Here the principles of operation of these clocks are discussed and, in particular, a novel concept of magic trapping of atoms in optical lattices. Recently proposed microwave lattice clocks are also highlights and several applications that employ the optical lattice clocks as a platform for precision measurements and quantum information processing.

  4. Colloquium: Physics of optical lattice clocks

    SciTech Connect

    Derevianko, Andrei; Katori, Hidetoshi

    2011-04-01

    Recently invented and demonstrated optical lattice clocks hold great promise for improving the precision of modern time keeping. These clocks aim at the 10{sup -18} fractional accuracy, which translates into a clock that would neither lose nor gain a fraction of a second over an estimated age of the Universe. In these clocks, millions of atoms are trapped and interrogated simultaneously, dramatically improving clock stability. Here the principles of operation of these clocks are discussed and, in particular, a novel concept of magic trapping of atoms in optical lattices. Recently proposed microwave lattice clocks are also highlights and several applications that employ the optical lattice clocks as a platform for precision measurements and quantum information processing.

  5. Correlations of Pairs in Bichromatic Optical Lattices

    NASA Astrophysics Data System (ADS)

    Li, Yan; He, Zhi

    2017-09-01

    Correlation functions of two interacting bosons in bound states confined in a quasi-periodic 1D optical lattice are investigated. This two-body problem is exactly solvable, and therefore, various correlation functions can be directly calculated. The first-order correlation and the resulting momentum distribution behave smoothly across the phase boundary and exhibit a strong dependence on the sign of on-site interactions. We demonstrate that this special signature of momentum distribution exists for both the extended phase and the localized phase. In addition to the dependence on the sign of on-site interactions, the second-order quantum coherence reveals complementary information about the quasi-periodic order of the system, the underling structure of the bound states and the characterization of the different phases of the bound states. We also study the second-order correlation in momentum space of the bound states in both the weak and strong coupling regimes and demonstrate different correlation patterns in these two regimes.

  6. DESIGN OF THE RCMS LATTICE OPTICS.

    SciTech Connect

    CARDONA,J.; KEWISCH,J.; PEGGS,S.

    2002-06-02

    THE RAPID CYCLING MEDICAL SYNCHROTRON (RCMS) IS DESIGNED TO BE A VERY LIGHT AND INEXPENSIVE ACCELERATOR. THIS IS POSSIBLE DUE TO THE SMALL BEAM SIZE THAT HAS BEEN CHOSEN EARLY DURING THE DESIGN STAGE. THIS CHOICE HAS IMPLICATIONS IN THE DESIGN OF THE LATTICE OPTICS. IN THIS PAPER, WE PRESENT AN OVERVIEW OF THE RCMS OPTICS LATTICE, THE KIND OF MAGNETS TO BE USED AND ALSO A DESCRIPTION OF A SPECIAL OPTIC MODULE THAT MATCHES THE ROTATING GANTRY WITH THE REST OF THE FIXED ACCELERATOR. TECHNIQUESDEVELOPED TO WIN ADDITIONAL SPACE BETWEEN QUADRUPOLES WITHOUT DISTRUBING BETA FUNCTIONS ARE ALSO PRESENTED.

  7. The optical potential on the lattice

    NASA Astrophysics Data System (ADS)

    Agadjanov, Dimitri; Döring, Michael; Mai, Maxim; Meißner, Ulf-G.; Rusetsky, Akaki

    2016-06-01

    The extraction of hadron-hadron scattering parameters from lattice data by using the Lüscher approach becomes increasingly complicated in the presence of inelastic channels. We propose a method for the direct extraction of the complex hadron-hadron optical potential on the lattice, which does not require the use of the multi-channel Lüscher formalism. Moreover, this method is applicable without modifications if some inelastic channels contain three or more particles.

  8. The optical potential on the lattice

    SciTech Connect

    Agadjanov, Dimitri; Doring, Michael; Mai, Maxim; MeiBner, Ulf -G.; Rusetsky, Akaki

    2016-06-08

    The extraction of hadron-hadron scattering parameters from lattice data by using the Luscher approach becomes increasingly complicated in the presence of inelastic channels. We propose a method for the direct extraction of the complex hadron-hadron optical potential on the lattice, which does not require the use of the multi-channel Luscher formalism. Furthermore, this method is applicable without modifications if some inelastic channels contain three or more particles.

  9. The optical potential on the lattice

    DOE PAGES

    Agadjanov, Dimitri; Doring, Michael; Mai, Maxim; ...

    2016-06-08

    The extraction of hadron-hadron scattering parameters from lattice data by using the Luscher approach becomes increasingly complicated in the presence of inelastic channels. We propose a method for the direct extraction of the complex hadron-hadron optical potential on the lattice, which does not require the use of the multi-channel Luscher formalism. Furthermore, this method is applicable without modifications if some inelastic channels contain three or more particles.

  10. Cold bosons in noisy optical lattices

    NASA Astrophysics Data System (ADS)

    Schachenmayer, Johannes; Pichler, Hannes; Zoller, Peter; Daley, Andrew

    2012-02-01

    Cold atoms in optical lattices open the possibility to experimentally study strongly interacting many-body quantum systems with controllable parameters. A key challenge to prepare interesting quantum states in these systems is to achieve sufficiently low temperatures. At these temperatures a deep theoretical understanding of possible heating processes and how they affect the characteristics of the quantum state becomes essential. In every realistic experiment there exist many sources of noise that cause phase and amplitude fluctuations in the standing laser waves that form the optical lattice potential. This classical noise can lead to heating and a significant change of the quantum state. We study the stochastic many-body non-equilibrium dynamics of bosons in an optical lattice and determine how the state changes depending on the characteristics of the noise. We do this by solving time-dependent stochastic many-body Schr"odinger equations, both analytically and numerically.

  11. Quantum Computation with Neutral Atoms at Addressable Optical Lattice Sites and Atoms in Confined Geometries

    DTIC Science & Technology

    2014-10-13

    SECURITY CLASSIFICATION OF: We have performed a set of experiments using arrays of 1D Bose gases in various configurations. Uncoupled 1D gases have been...used to study the limits of statistical mechanics near integrable points. We have shown that nearly integrable gases thermalize at an even slower...NAME(S) AND ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 ultracold atoms, optical lattices, 1D gases

  12. Atoms in non-dissipative optical lattices

    NASA Astrophysics Data System (ADS)

    Bergamini, Silvia

    Optical lattices induced by light detuned far from the frequency of any atomic resonance transition are ideal systems in which to develop techniques for the coherent control of atomic motional and internal states. Decoherence arising from spontaneous emission can be eliminated to an arbitrary degree by varying the detuning of the optical field. The atoms trapped in these lattices are to a large extent isolated from environmental disturbances and from each other. The first step towards the coherent control of atoms in a far-detuned lattice is their preparation in a single motional state. In this thesis the preparation of atoms in the ground vibrational state of a two-dimensional far-detuned optical lattice via resolved-sideband Raman cooling is presented. This sideband-cooling scheme involves stimulated Raman transitions between bound vibrational states of a pair of magnetic ground state sublevels, followed by an irreversible step due to optical pumping, resulting in a net loss of one quantum of vibrational energy per cooling cycle. This process provides efficient cooling in two-dimensions and leads to the accumulation of a large fraction of atoms in the 2-D ground vibrational state of a potential well associated with a single Zeeman substate. Experiments aimed at improving and monitoring the characteristics of the lar-detuned lattice and the sideband-Raman cooling efficiency are also described. Parametric excitation experiments and modelling are employed to investigate the degree of anharmonicity of the optical potential and the importance of heating induced by laser intensity noise, whilst Zeeman-state analysis of the sample is performed for monitoring the distribution of atoms over different magnetic sub- states. Finally, spin-polarization experiments are carried out in order to study the paramagnetic properties of the lattice and lead to an evaluation of a spin-temperature for the sample.

  13. Ultra-Cold Atoms on Optical Lattices

    ERIC Educational Resources Information Center

    Ghosh, Parag

    2009-01-01

    The field of ultra-cold atoms, since the achievement of Bose-Einstein Condensation (Anderson et al., 1995; Davis et al., 1995; Bradley et al., 1995), have seen an immensely growing interest over the past decade. With the creation of optical lattices, new possibilities of studying some of the widely used models in condensed matter have opened up.…

  14. Atomic Current across an Optical Lattice

    SciTech Connect

    Ponomarev, Alexey V.; Kolovsky, Andrey R.; Madronero, Javier; Buchleitner, Andreas

    2006-02-10

    We devise a microscopic model for the emergence of a collision-induced, fermionic atomic current across a tilted optical lattice. Tuning the--experimentally controllable--parameters of the microscopic dynamics allows us to switch from Ohmic to negative differential conductance.

  15. Delocalized entanglement of atoms in optical lattices.

    PubMed

    Vollbrecht, K G H; Cirac, J I

    2007-05-11

    We show how to detect and quantify entanglement of atoms in optical lattices in terms of correlation functions of the momentum distribution. These distributions can be measured directly in the experiments. We introduce two kinds of entanglement measures related to the position and the spin of the atoms.

  16. Ultra-Cold Atoms on Optical Lattices

    ERIC Educational Resources Information Center

    Ghosh, Parag

    2009-01-01

    The field of ultra-cold atoms, since the achievement of Bose-Einstein Condensation (Anderson et al., 1995; Davis et al., 1995; Bradley et al., 1995), have seen an immensely growing interest over the past decade. With the creation of optical lattices, new possibilities of studying some of the widely used models in condensed matter have opened up.…

  17. Optical trapping of nanoscale plasmonic optical lattice in microfluidic environments

    NASA Astrophysics Data System (ADS)

    Hung, Chia-Chun; Huang, Jer-Shing; Yang, Ya-Tang

    2014-09-01

    Recent advances in optical manipulation have made it an ideal tool to create one, two, and three dimensional periodic optical potential. Such periodic potentials have found interesting technological and fundamental applications such as micro particle sorting and optical fractionation. Plasmon enhanced optical trapping techniques using metallic nanostructures can overcome the diffraction limits of far-field optical trap techniques and therefore permit trapping of nanoparticle with deep sub wavelength dimensions. Here we report the trapping of nanoparticles for a plasmon-enhanced two dimensional optical lattice integrated with microfluidic chip. We observe the trapping of nanoparticles over such an optical lattice. Such an integrated device allows the directional control of nano particles and provides a suitable platform for stochastic transport experiment such as nanoscale optical sorting.

  18. Enhancement of long-range correlations in a 2D vortex lattice by an incommensurate 1D disorder potential

    NASA Astrophysics Data System (ADS)

    Guillamon, I.; Vieira, S.; Suderow, H.; Cordoba, R.; Sese, J.; de Teresa, J. M.; Ibarra, R.

    In two dimensional (2D) systems, theory has proposed that random disorder destroys long range correlations driving a transition to a glassy state. Here, I will discuss new insights into this issue obtained through the direct visualization of the critical behaviour of a 2D superconducting vortex lattice formed in a thin film with a smooth 1D thickness modulation. Using scanning tunneling microscopy at 0.1K, we have tracked the modification in the 2D vortex arrangements induced by the 1D thickness modulation while increasing the vortex density by three orders of magnitude. Upon increasing the field, we observed a two-step order-disorder transition in the 2D vortex lattice mediated by the appearance of dislocations and disclinations and accompanied by an increase in the local vortex density fluctuations. Through a detailed analysis of correlation functions, we find that the transition is driven by the incommensurate 1D thickness modulation. We calculate the critical points and exponents and find that they are well above theoretical expectation for random disorder. Our results show that long range 1D correlations in random potentials enhance the stability range of the ordered phase in a 2D vortex lattice. Work supported by Spanish MINECO, CIG Marie Curie Grant, Axa Research Fund and FBBVA.

  19. Controlling polar molecules in optical lattices

    SciTech Connect

    Kotochigova, S.; Tiesinga, E.

    2006-04-15

    We theoretically investigate the interaction of polar molecules with optical lattices and microwave fields. We demonstrate the existence of frequency windows in the optical domain where the complex internal structure of the molecule does not influence the trapping potential of the lattice. In such frequency windows the Franck-Condon factors are so small that near-resonant interaction of vibrational levels of the molecule with the lattice fields have a negligible contribution to the polarizability, and light-induced decoherences are kept to a minimum. In addition, we show that microwave fields can induce a tunable dipole-dipole interaction between ground-state rotationally symmetric (J=0) molecules. A combination of a carefully chosen lattice frequency and microwave-controlled interaction between molecules will enable trapping of polar molecules in a lattice and possibly realize molecular quantum logic gates. Our results are based on ab initio relativistic electronic structure calculations of the polar KRb and RbCs molecules combined with calculations of their rovibrational motion.

  20. Ultracold Quantum Gases in Hexagonal Optical Lattices

    NASA Astrophysics Data System (ADS)

    Sengstock, Klaus

    2010-03-01

    Hexagonal structures occur in a vast variety of systems, ranging from honeycombs of bees in life sciences to carbon nanotubes in material sciences. The latter, in particular its unfolded two-dimensional layer -- Graphene -- has rapidly grown to one of the most discussed topics in condensed-matter physics. Not only does it show proximity to various carbon-based materials but also exceptional properties owing to its unusual energy spectrum. In quantum optics, ultracold quantum gases confined in periodic light fields have shown to be very general and versatile instruments to mimic solid state systems. However, so far nearly all experiments were performed in cubic lattice geometries only. Here we report on the first experimental realization of ultracold quantum gases in a state-dependent, two-dimensional, Graphene-like optical lattice with hexagonal symmetry. The lattice is realized via a spin-dependent optical lattice structure with alternating σ^+ and σ^- -sites and thus constitutes a so called `magnetic'-lattice with `antiferromagnetic'-structure. Atoms with different spin orientation can be loaded to specific lattice sites or -- depending on the parameters -- to the whole lattice. As a consequence e.g. superpositions of a superfluid spin component with a different spin component in the Mott-insulating phase can be realized as well as spin-dependent transport properties, disorder etc. After preparing an antiferromagnetically ordered state we e.g. measure sustainable changes of the transport properties of the atoms. This manifests in a significant reduction of the tunneling as compared to a single-component system. We attribute this observation to a partial tunneling blockade for one spin component induced by population in another spin component localized at alternating lattice sites. Within a Gutzwiller-Ansatz we calculate the phase diagrams for the mixed spin-states and find very good agreement with our experimental results. Moreover, by state-resolved recording

  1. Fibonacci optical lattices for tunable quantum quasicrystals

    NASA Astrophysics Data System (ADS)

    Singh, K.; Saha, K.; Parameswaran, S. A.; Weld, D. M.

    2015-12-01

    We describe a quasiperiodic optical lattice, created by a physical realization of the abstract cut-and-project construction underlying all quasicrystals. The resulting potential is a generalization of the Fibonacci tiling. Calculation of the energies and wave functions of ultracold atoms loaded into such a lattice demonstrate a multifractal energy spectrum, a singular continuous momentum-space structure, and the existence of controllable edge states. These results open the door to cold atom quantum simulation experiments in tunable or dynamic quasicrystalline potentials, including topological pumping of edge states and phasonic spectroscopy.

  2. Resonant and Soliton Transport of Ultracold Atoms on Optical Lattices

    NASA Astrophysics Data System (ADS)

    Rubbo, Chester Philipp

    In this thesis, we present a theoretical study of the dynamics of strongly interacting ultracold atoms in optical lattices. At ultracold temperatures, the dynamics cannot be described classically, but instead, must take into account quantum effects. Here, our focus is on transport and precision measurement. We use exact analysis of few-body systems and mean field analysis. For larger systems, we use a numerical approach called the density matrix renormalization group (DMRG) method which is considered an efficient computational tool for the quantum evolution of 1D systems. After introducing basic concepts, we treat the motional properties of particles in a tilted lattice in a regime where the inter-particle interactions are resonant with the linear potential. In this regime, the dynamics is described by an Ising model with a transverse field which is a basic system to study quantum magnetism and quantum phase transitions. We introduce analytical and numerical methods to draw a simple picture of the dynamics. This helps us to formulate a slinky-like transport scheme that provides full control of the motional direction of particles. After a study of transport on a tilted lattice, we treat the transport of nonlinear waves in strongly interacting systems. These nonlinear waves are called solitons, which are described as local perturbations of a medium that survive after collisions. We identify two species of classical soliton solutions in our system and study their stability under quantum evolution via DMRG. We shift focus from the dynamics related to transport and turn to precision measurements in optical lattice clocks. Here, we investigate one aspect of their limitations which is due to collisions of atoms loaded onto a single site. These collisions introduce a frequency shift in the clock measurement. We provide a microscopic description of the origin of this frequency shift. Our results have motivated improvement in the accuracy and precision of next generation

  3. Twisted complex superfluids in optical lattices

    PubMed Central

    Jürgensen, Ole; Sengstock, Klaus; Lühmann, Dirk-Sören

    2015-01-01

    We show that correlated pair tunneling drives a phase transition to a twisted superfluid with a complex order parameter. This unconventional superfluid phase spontaneously breaks the time-reversal symmetry and is characterized by a twisting of the complex phase angle between adjacent lattice sites. We discuss the entire phase diagram of the extended Bose—Hubbard model for a honeycomb optical lattice showing a multitude of quantum phases including twisted superfluids, pair superfluids, supersolids and twisted supersolids. Furthermore, we show that the nearest-neighbor interactions lead to a spontaneous breaking of the inversion symmetry of the lattice and give rise to dimerized density-wave insulators, where particles are delocalized on dimers. For two components, we find twisted superfluid phases with strong correlations between the species already for surprisingly small pair-tunneling amplitudes. Interestingly, this ground state shows an infinite degeneracy ranging continuously from a supersolid to a twisted superfluid. PMID:26345721

  4. Twisted complex superfluids in optical lattices.

    PubMed

    Jürgensen, Ole; Sengstock, Klaus; Lühmann, Dirk-Sören

    2015-09-08

    We show that correlated pair tunneling drives a phase transition to a twisted superfluid with a complex order parameter. This unconventional superfluid phase spontaneously breaks the time-reversal symmetry and is characterized by a twisting of the complex phase angle between adjacent lattice sites. We discuss the entire phase diagram of the extended Bose-Hubbard model for a honeycomb optical lattice showing a multitude of quantum phases including twisted superfluids, pair superfluids, supersolids and twisted supersolids. Furthermore, we show that the nearest-neighbor interactions lead to a spontaneous breaking of the inversion symmetry of the lattice and give rise to dimerized density-wave insulators, where particles are delocalized on dimers. For two components, we find twisted superfluid phases with strong correlations between the species already for surprisingly small pair-tunneling amplitudes. Interestingly, this ground state shows an infinite degeneracy ranging continuously from a supersolid to a twisted superfluid.

  5. The NIM Sr Optical Lattice Clock

    NASA Astrophysics Data System (ADS)

    Lin, Y.; Wang, Q.; Li, Y.; Meng, F.; Lin, B.; Zang, E.; Sun, Z.; Fang, F.; Li, T.; Fang, Z.

    2016-06-01

    A 87Sr optical lattice clock is built at the National Institute of Metrology (NIM) of China. The atoms undergo two stages of laser cooling before being loaded into a horizontal optical lattice at the magic wavelength of 813 nm. After being interrogated by a narrow linewidth 698 nm clock laser pulse, the normalized excitation rate is measured to get the frequency error, which is then used to lock the clock laser to the ultra-narrow 1S0-3P0 clock transition. The total systematic uncertainty of the clock is evaluated to be 2.3 × 10-16, and the absolute frequency of the clock is measured to be 429 228 004 229 873.7(1.4) Hz with reference to the NIM5 cesium fountain.

  6. Fast dynamics for atoms in optical lattices.

    PubMed

    Łącki, Mateusz; Zakrzewski, Jakub

    2013-02-08

    Cold atoms in optical lattices allow for accurate studies of many body dynamics. Rapid time-dependent modifications of optical lattice potentials may result in significant excitations in atomic systems. The dynamics in such a case is frequently quite incompletely described by standard applications of tight-binding models (such as, e.g., Bose-Hubbard model or its extensions) that typically neglect the effect of the dynamics on the transformation between the real space and the tight-binding basis. We illustrate the importance of a proper quantum mechanical description using a multiband extended Bose-Hubbard model with time-dependent Wannier functions. We apply it to situations directly related to experiments.

  7. Strongly correlated quantum walks in optical lattices.

    PubMed

    Preiss, Philipp M; Ma, Ruichao; Tai, M Eric; Lukin, Alexander; Rispoli, Matthew; Zupancic, Philip; Lahini, Yoav; Islam, Rajibul; Greiner, Markus

    2015-03-13

    Full control over the dynamics of interacting, indistinguishable quantum particles is an important prerequisite for the experimental study of strongly correlated quantum matter and the implementation of high-fidelity quantum information processing. We demonstrate such control over the quantum walk-the quantum mechanical analog of the classical random walk-in the regime where dynamics are dominated by interparticle interactions. Using interacting bosonic atoms in an optical lattice, we directly observed fundamental effects such as the emergence of correlations in two-particle quantum walks, as well as strongly correlated Bloch oscillations in tilted optical lattices. Our approach can be scaled to larger systems, greatly extending the class of problems accessible via quantum walks. Copyright © 2015, American Association for the Advancement of Science.

  8. Spin-1/2 Optical Lattice Clock

    NASA Astrophysics Data System (ADS)

    Lemke, N. D.; Ludlow, A. D.; Barber, Z. W.; Fortier, T. M.; Diddams, S. A.; Jiang, Y.; Jefferts, S. R.; Heavner, T. P.; Parker, T. E.; Oates, C. W.

    2009-08-01

    We experimentally investigate an optical clock based on Yb171 (I=1/2) atoms confined in an optical lattice. We have evaluated all known frequency shifts to the clock transition, including a density-dependent collision shift, with a fractional uncertainty of 3.4×10-16, limited principally by uncertainty in the blackbody radiation Stark shift. We measured the absolute clock transition frequency relative to the NIST-F1 Cs fountain clock and find the frequency to be 518 295 836 590 865.2(0.7) Hz.

  9. Spin-1/2 Optical Lattice Clock

    SciTech Connect

    Lemke, N. D.; Ludlow, A. D.; Barber, Z. W.; Fortier, T. M.; Diddams, S. A.; Jiang, Y.; Jefferts, S. R.; Heavner, T. P.; Parker, T. E.; Oates, C. W.

    2009-08-07

    We experimentally investigate an optical clock based on {sup 171}Yb (I=1/2) atoms confined in an optical lattice. We have evaluated all known frequency shifts to the clock transition, including a density-dependent collision shift, with a fractional uncertainty of 3.4x10{sup -16}, limited principally by uncertainty in the blackbody radiation Stark shift. We measured the absolute clock transition frequency relative to the NIST-F1 Cs fountain clock and find the frequency to be 518 295 836 590 865.2(0.7) Hz.

  10. Deviations from Boltzmann-Gibbs Statistics in Confined Optical Lattices.

    PubMed

    Dechant, Andreas; Kessler, David A; Barkai, Eli

    2015-10-23

    We investigate the semiclassical phase-space probability distribution P(x,p) of cold atoms in a Sisyphus cooling lattice with an additional harmonic confinement. We pose the question of whether this nonequilibrium steady state satisfies the equivalence of energy and probability. This equivalence is the foundation of Boltzmann-Gibbs and generalized thermostatic statistics, and a prerequisite for the description in terms of a temperature. At large energies, P(x,p) depends only on the Hamiltonian H(x,p) and the answer to the question is yes. In distinction to the Boltzmann-Gibbs state, the large-energy tails are power laws P(x,p)∝H(x,p)(-1/D), where D is related to the depth of the optical lattice. At intermediate energies, however, P(x,p) cannot be expressed as a function of the Hamiltonian and the equivalence between energy and probability breaks down. As a consequence the average potential and kinetic energy differ and no well-defined temperature can be assigned. The Boltzmann-Gibbs state is regained only in the limit of deep optical lattices. For strong confinement relative to the damping, we derive an explicit expression for the stationary phase-space distribution.

  11. Microfluidic sorting in an optical lattice

    NASA Astrophysics Data System (ADS)

    MacDonald, M. P.; Spalding, G. C.; Dholakia, K.

    2003-11-01

    The response of a microscopic dielectric object to an applied light field can profoundly affect its kinetic motion. A classic example of this is an optical trap, which can hold a particle in a tightly focused light beam. Optical fields can also be used to arrange, guide or deflect particles in appropriate light-field geometries. Here we demonstrate an optical sorter for microscopic particles that exploits the interaction of particles-biological or otherwise-with an extended, interlinked, dynamically reconfigurable, three-dimensional optical lattice. The strength of this interaction with the lattice sites depends on the optical polarizability of the particles, giving tunable selection criteria. We demonstrate both sorting by size (of protein microcapsule drug delivery agents) and sorting by refractive index (of other colloidal particle streams). The sorting efficiency of this method approaches 100%, with values of 96% or more observed even for concentrated solutions with throughputs exceeding those reported for fluorescence-activated cell sorting. This powerful, non-invasive technique is suited to sorting and fractionation within integrated (`lab-on-a-chip') microfluidic systems, and can be applied in colloidal, molecular and biological research.

  12. Damping of condensate modes of trapped atoms in an optical lattice

    NASA Astrophysics Data System (ADS)

    Luxat, D. L.; Tsuchiya, S.; Griffin, A.

    2003-05-01

    We calculate the collisional damping of collective modes of a harmonically confined Bose condensate in an optical lattice at finite temperatures. We extend recent work [1] to obtain a generalized finite temperature Stringari equation for the condensate collective modes, which includes a damping term arising from the lack of diffusive equilibrium when a condensate moves in a static thermal cloud. This intercomponent collisional damping is calculated for a cigar-shaped harmonic trap for varying 1D optical lattice depths. We also estimate the Landau damping. We compare our results with recent data on collective modes in an optical lattice [2]. The effect of the optical lattice and magnetic trap on the condensate and noncondensate density profiles is calculated as a function of the temperature using the TF approximation. [1] M. Krämer et. al., Phys. Rev. Lett. 88, 180404 (2002). [2] F. Ferlaino et. al., Phys. Rev. A 66, 011604 (2002).

  13. An Accurate Multi-level Finite Difference Scheme for 1D Diffusion Equations Derived from the Lattice Boltzmann Method

    NASA Astrophysics Data System (ADS)

    Suga, Shinsuke

    2010-08-01

    An accurate and unconditionally stable explicit finite difference scheme for 1D diffusion equations is derived from the lattice Boltzmann method with rest particles. The system of the lattice Boltzmann equations for the distribution of the number of the fictitious particles is rewritten as a four-level explicit finite difference equation for the concentration of the diffused matter with two parameters. The consistency analysis of the four-level scheme shows that the two parameters which appear in the scheme, the relaxation parameter and the amount of rest particles, can be determined such that the scheme has the truncation error of fourth order. Numerical experiments demonstrate the fourth-order rate of convergence for various combinations of model parameters.

  14. Quantum theory of cold bosonic atoms in optical lattices

    SciTech Connect

    Tilahun, Dagim; Duine, R. A.; MacDonald, A. H.

    2011-09-15

    Ultracold atoms in optical lattices undergo a quantum phase transition from a superfluid to a Mott insulator as the lattice potential depth is increased. We describe an approximate theory of interacting bosons in optical lattices which provides a qualitative description of both superfluid and insulator states. The theory is based on a change of variables in which the boson coherent state amplitude is replaced by an effective potential which promotes phase coherence between different number states on each lattice site. It is illustrated here by applying it to uniform and fully frustrated lattice cases but is simple enough that it can be applied to spatially inhomogeneous lattice systems.

  15. Topological defect formation in 1D and 2D spin chains realized by network of optical parametric oscillators

    NASA Astrophysics Data System (ADS)

    Hamerly, Ryan; Inaba, Kensuke; Inagaki, Takahiro; Takesue, Hiroki; Yamamoto, Yoshihisa; Mabuchi, Hideo

    2016-09-01

    A network of optical parametric oscillators (OPOs) is used to simulate classical Ising and XY spin chains. The collective nonlinear dynamics of this network, driven by quantum noise rather than thermal fluctuations, seeks out the Ising/XY ground state as the system transitions from below to above the lasing threshold. We study the behavior of this “Ising machine” for three canonical problems: a 1D ferromagnetic spin chain, a 2D square lattice and problems where next-nearest-neighbor couplings give rise to frustration. If the pump turn-on time is finite, topological defects form (domain walls for the Ising model, winding number and vortices for XY) and their density can be predicted from a numerical model involving a linear “growth stage” and a nonlinear “saturation stage”. These predictions are compared against recent data for a 10,000-spin 1D Ising machine.

  16. Observation of Stueckelberg oscillations in accelerated optical lattices

    SciTech Connect

    Zenesini, A.; Ciampini, D.; Arimondo, E.; Morsch, O.

    2010-12-15

    We report the experimental observation of Stueckelberg oscillations of matter waves in optical lattices. Extending previous work on Landau-Zener tunneling of Bose-Einstein condensates in optical lattices, we study the effects of the accumulated phase between two successive crossings of the Brillouin zone edge. Our results agree well with a simple model for multiple Landau-Zener tunneling events taking into account the band structure of the optical lattice.

  17. A low maintenance Sr optical lattice clock

    NASA Astrophysics Data System (ADS)

    Hill, I. R.; Hobson, R.; Bowden, W.; Bridge, E. M.; Donnellan, S.; Curtis, E. A.; Gill, P.

    2016-06-01

    We describe the Sr optical lattice clock apparatus at NPL with particular emphasis on techniques used to increase reliability and minimise the human requirement in its operation. Central to this is a clock-referenced transfer cavity scheme for the stabilisation of cooling and trapping lasers. We highlight several measures to increase the reliability of the clock with a view towards the realisation of an optical time-scale. The clock contributed 502 hours of data over a 25 day period (84% uptime) in a recent measurement campaign with several uninterrupted periods of more than 48 hours. An instability of 2 x 10-17 was reached after 105 s of averaging in an interleaved self-comparison of the clock.

  18. Quantization of Energy in 1D Model of Crystal Lattice with Local Perturbations Induced by Ion-Beam Impact

    NASA Astrophysics Data System (ADS)

    Minárik, Stanislav

    2015-08-01

    In this paper, we propose theoretical basis for investigation of dynamics of acoustic phonons in a thin layers containing nano-scale structural inhomogeneities. One-dimensional (1D) model of a crystal lattice was considered to reveal specific features of the processes arising in such system of phonons in equilibrium state. Standard quantization of energy of 1D ionic chain vibrating by acoustic frequencies was carried out while the presence of foreign ions in this chain was taken into account. Since only two dimensions are dominant in thin layers, only longitudinal vibrations of the chain in the plane of the layer were considered. Results showed that foreign ions affect the energy quantization. Phonon-phonon interaction between two phonon`s modes can be expected if the mass of foreign ions implanted by ion-beam differs from the mass of ions in the initial layer. We believe that the obtained results will help to understand the character of phonon systems in nanostructured thin layers prepared by ion-bem technology, and will allow better explain some thermal and electrical phenomena associated with lattice dynamics in such layers.

  19. Marriage of exact enumeration and 1/d expansion methods: Lattice model of dilute polymers

    NASA Astrophysics Data System (ADS)

    Nemirovsky, A. M.; Freed, Karl F.; Ishinabe, Takao; Douglas, Jack F.

    1992-06-01

    We consider the properties of a self-avoiding polymer chain with nearestneighbor contact energy ɛ on a d-dimensional hypercubic lattice. General theoretical arguments enable us to prescribe the exact analytic form of the n-segment chain partition function C n ,and unknown coefficients for chains of up to 11 segments are determined using exact enumeration data in d=2-6. This exact form provides the main ingredient to produce a large- n expansion in d -1of the chain free energy through fifth order with the full dependence on the contact energy retained. The ɛ-dependent chain connectivity constant and free energy amplitude are evaluated within the d -1expansion to O(d -5). Our general formulation includes for the first time self-avoiding walks, neighboravoiding walks, theta, and collapsed chains as particular limiting cases.

  20. On the spectrum of the lattice spin-boson Hamiltonian for any coupling: 1D case

    SciTech Connect

    Muminov, M.; Neidhardt, H.; Rasulov, T.

    2015-05-15

    A lattice model of radiative decay (so-called spin-boson model) of a two level atom and at most two photons is considered. The location of the essential spectrum is described. For any coupling constant, the finiteness of the number of eigenvalues below the bottom of its essential spectrum is proved. The results are obtained by considering a more general model H for which the lower bound of its essential spectrum is estimated. Conditions which guarantee the finiteness of the number of eigenvalues of H below the bottom of its essential spectrum are found. It is shown that the discrete spectrum might be infinite if the parameter functions are chosen in a special form.

  1. Nuclear spin effects in optical lattice clocks

    SciTech Connect

    Boyd, Martin M.; Zelevinsky, Tanya; Ludlow, Andrew D.; Blatt, Sebastian; Zanon-Willette, Thomas; Foreman, Seth M.; Ye Jun

    2007-08-15

    We present a detailed experimental and theoretical study of the effect of nuclear spin on the performance of optical lattice clocks. With a state-mixing theory including spin-orbit and hyperfine interactions, we describe the origin of the {sup 1}S{sub 0}-{sup 3}P{sub 0} clock transition and the differential g factor between the two clock states for alkaline-earth-metal(-like) atoms, using {sup 87}Sr as an example. Clock frequency shifts due to magnetic and optical fields are discussed with an emphasis on those relating to nuclear structure. An experimental determination of the differential g factor in {sup 87}Sr is performed and is in good agreement with theory. The magnitude of the tensor light shift on the clock states is also explored experimentally. State specific measurements with controlled nuclear spin polarization are discussed as a method to reduce the nuclear spin-related systematic effects to below 10{sup -17} in lattice clocks.

  2. Compact flat band states in optically induced flatland photonic lattices

    NASA Astrophysics Data System (ADS)

    Travkin, Evgenij; Diebel, Falko; Denz, Cornelia

    2017-07-01

    We realize low-dimensional tight-binding lattices that host flat bands in their dispersion relation and demonstrate the existence of optical compact flat band states. The lattices are resembled by arrays of optical waveguides fabricated by the state-of-the-art spatio-temporal Bessel beam multiplexing optical induction in photorefractive media. We work out the decisive details of the transition from the discrete theory to the real optical system ensuring that the experimental lattices stand up to numerical scrutiny exhibiting well-approximated band structures. Our highly flexible system is a promising candidate for further experimental investigation of theoretically studied disorder effects in flat band lattices.

  3. Effect of impurities on the vortex lattice in Bose-Einstein condensates on optical lattice

    NASA Astrophysics Data System (ADS)

    Mithun, T.; Porsezian, K.; Dey, Bishwajyoti

    2015-06-01

    We numerically solve the Gross-Pitaeveskii equation to study the Bose-Einstein condensate in the rotating harmonical tarp and co-rotating optical lattice. The effect of a pinning site or impurity shows that it is able to move the vortex lattice center to either left or right depending on the position of the impurity. Also, it is observed that the impurity at the random positions can destroy the vortex lattice and the resulting disordered lattice has more energy.

  4. Intrinsic Localized Modes in Optical Photonic Lattices and Arrays

    NASA Astrophysics Data System (ADS)

    Christodoulides, Demetrios

    -locking and pulse compression. A strong signature of discrete X-wave formation was also demonstrated in such structures. In the last few years, Anderson localization was unequivocally observed in array systems where the transition from ballistic transport to diffusive, and the cross-over to Anderson localization was studied as a function of disorder and nonlinearity. In recent studies synthetic lattices exhibiting parity-time (PT) symmetry were also considered. The interplay of gain and loss in this latter family of structures leads to counterintuitive characteristics and behavior such as non-reciprocal propagation and power oscillations. The realization of discrete array systems at su-bwavelenth scales is another important direction that is nowadays intensively pursued. References 1. D. N. Christodoulides, F. Lederer, and Y. Silberberg, Nature 424, 817- 823 (2003). 2. F. Lederer, G. I. Stegeman, D. N. Christodoulides, G. Assanto, M. Segev and Y. Silberberg, Phys. Reports 463, 1-126 (2008). 3. M Wimmer, A Regensburger, MA Miri, C. Bersch, D.N Christodoulides, and U. Peschel, ''Observation of optical solitons in PT-symmetric lattices'' Nature Communications 6, 7782 (2015). Intrinsic Localized Modes in Optical Photonic Lattices and Arrays.

  5. Optical lattice trap for Kerr solitons

    NASA Astrophysics Data System (ADS)

    Taheri, Hossein; Matsko, Andrey B.; Maleki, Lute

    2017-06-01

    We show theoretically and numerically that dichromatic pumping of a nonlinear microresonator by two continuous wave coherent optical pumps creates an optical lattice trap that results in the localization of intra-cavity Kerr solitons with soliton positions defined by the beat frequency of the two pumps. This phenomenon corresponds to the stabilization of the comb repetition rate. The locking of the second pump, through adiabatic tuning of its frequency, to the comb generated by the first pump allows transitioning to single-soliton states, manipulating the position of Kerr solitons in the cavity, and tuning the frequency comb repetition rate within the locking range. It also explains soliton crystal formation in resonators supporting a dispersive wave emitted as a result of higher-order group velocity dispersion or avoided mode crossing. We show that dichromatic pumping by externally stabilized pumps can be utilized for stabilization of microresonator-based optical frequency combs when the comb span does not cover an octave or a significant fraction thereof and standard self-referencing techniques cannot be employed. Our findings have significant ramifications for high-precision applications of optical frequency combs in spectrally pure signal generation, metrology, and timekeeping.

  6. Soliton spiraling in optically induced rotating Bessel lattices.

    PubMed

    Kartashov, Yaroslav V; Vysloukh, Victor A; Torner, Lluis

    2005-03-15

    We address soliton spiraling in optical lattices induced by multiple coherent Bessel beams and show that the dynamic nature of such lattices makes it possible for them to drag different soliton structures, setting them into rotation. We can control the rotation rate by varying the topological charges of lattice-inducing Bessel beams.

  7. Transport of an interacting Bose gas in 1D disordered lattices

    SciTech Connect

    D'Errico, C.; Chaudhuri, S.; Gori, L.; Kumar, A.; Lucioni, E.; Tanzi, L.; Inguscio, M.; Modugno, G.

    2014-08-20

    We use ultracold atoms in a quasiperiodic lattice to study two outstanding problems in the physics of disordered systems: a) the anomalous diffusion of a wavepacket in the presence of disorder, interactions and noise; b) the transport of a disordered superfluid. a) Our results show that the subdiffusion, observed when interaction alone is present, can be modelled with a nonlinear diffusion equation and the peculiar shape of the expanding density profiles can be connected to the microscopic nonlinear diffusion coefficients. Also when noise alone is present we can describe the observed normal diffusion dynamics by existing microscopic models. In the unexplored regime in which noise and interaction are combined, instead, we observe an anomalous diffusion, that we model with a generalized diffusion equation, where noise- and interaction-induced contributions add each other. b) We find that an instability appearing at relatively large momenta can be employed to locate the fluid-insulator crossover driven by disorder. By investigating the momentum-dependent transport, we observe a sharp crossover from a weakly dissipative regime to a strongly unstable one at a disorder-dependent critical momentum. The set of critical disorder and interaction strengths for which such critical momentum vanishes, can be identified with the separation between a fluid regime and an insulating one and can be related to the predicted zero-temperature superfluid-Bose glass transition.

  8. Chaos in the honeycomb optical-lattice unit cell

    NASA Astrophysics Data System (ADS)

    Porter, Max D.; Reichl, L. E.

    2016-01-01

    Natural and artificial honeycomb lattices are of great interest because the band structure of these lattices, if properly constructed, contains a Dirac point. Such lattices occur naturally in the form of graphene and carbon nanotubes. They have been created in the laboratory in the form of semiconductor 2DEGs, optical lattices, and photonic crystals. We show that, over a wide energy range, gases (of electrons, atoms, or photons) that propagate through these lattices are Lorentz gases and the corresponding classical dynamics is chaotic. Thus honeycomb lattices are also of interest for understanding eigenstate thermalization and the conductor-insulator transition due to dynamic Anderson localization.

  9. Mobile spin impurity in an optical lattice

    NASA Astrophysics Data System (ADS)

    Duncan, C. W.; Bellotti, F. F.; Öhberg, P.; Zinner, N. T.; Valiente, M.

    2017-07-01

    We investigate the Fermi polaron problem in a spin-1/2 Fermi gas in an optical lattice for the limit of both strong repulsive contact interactions and one dimension. In this limit, a polaronic-like behaviour is not expected, and the physics is that of a magnon or impurity. While the charge degrees of freedom of the system are frozen, the resulting tight-binding Hamiltonian for the impurity’s spin exhibits an intriguing structure that strongly depends on the filling factor of the lattice potential. This filling dependency also transfers to the nature of the interactions for the case of two magnons and the important spin balanced case. At low filling, and up until near unit filling, the single impurity Hamiltonian faithfully reproduces a single-band, quasi-homogeneous tight-binding problem. As the filling is increased and the second band of the single particle spectrum of the periodic potential is progressively filled, the impurity Hamiltonian, at low energies, describes a single particle trapped in a multi-well potential. Interestingly, once the first two bands are fully filled, the impurity Hamiltonian is a near-perfect realisation of the Su-Schrieffer-Heeger model. Our studies, which go well beyond the single-band approximation, that is, the Hubbard model, pave the way for the realisation of interacting one-dimensional models of condensed matter physics.

  10. Colloidal sorting in dynamic optical lattices

    NASA Astrophysics Data System (ADS)

    Smith, Ryan L.; Spalding, G. C.; Dholakia, K.; MacDonald, M. P.

    2007-08-01

    Passive microfluidic sorting techniques based upon the interaction of particles with an optically defined potential energy landscape have possible advantages over active sorting techniques such as microfluorescence activated cell sorting (FACS), including ease of integration into lab-on-a-chip systems, reconfigurability, and scalability. Rather than analysing and deflecting a single-file stream of particles one by one, a passive approach intrinsically aimed at parallel processing may, ultimately, offer greater potential for high throughput. However attempts to sort many particles simultaneously in high density suspensions are inevitably limited by particle particle interactions, which lead to a reduction in the efficiency of the sorting. In this paper we describe two different approaches aimed at reducing colloidal traffic flow problems. We find that continuous translation of the sorting lattice helps to reduce nearest neighbour particle spacing, providing promise for efficiency improvements in future high throughput applications, and that a flashing lattice yields a reduction in unwanted pile-up and spillover effects which otherwise limit the efficiency of sorting.

  11. The strontium optical lattice clock: Optical spectroscopy with sub-hertz accuracy

    NASA Astrophysics Data System (ADS)

    Ludlow, Andrew D.

    One of the most well-developed applications of coherent interaction with atoms is atomic frequency standards and clocks. Atomic clocks find significant roles in a number of scientific and technological settings. State-of-the-art, laser-cooled, Cs-fountain microwave clocks have demonstrated impressive frequency measurement accuracy, with fractional uncertainties below the 10-15 level. On the other hand, frequency standards based on optical transitions have made substantial steps forward over the last decade, benefiting from their high operational frequencies. An interesting approach to such an optical standard uses atomic strontium confined in an optical lattice. The tight atomic confinement allows for nearly complete elimination of Doppler and recoil-related effects which can otherwise trouble the precise atomic interrogation. At the same time, the optical lattice is designed to equally perturb the two electronic clock states so that the confinement introduces a net zero shift of the natural transition frequency. This thesis describes the design and realization of an optical frequency standard using 87Sr confined in a 1-D optical lattice. Techniques for atomic manipulation and control are described, including two-stage laser cooling, proper design of atomic confinement in a lattice potential, and optical pumping techniques. With the development of an ultra-stable coherent laser light source, atomic spectral linewidths of the optical clock transition are observed below 2 Hz. High accuracy spectroscopy of the clock transition is carried out utilizing a femtosecond frequency comb referenced to the NIST-F1 Cs fountain. To explore the performance of an improved, spin-polarized Sr standard, a coherent optical phase transfer link is established between JILA and NIST. This enables remote comparison of the Sr standard against optical standards at NIST, such as the cold Ca standard. The high frequency stability of a Sr-Ca comparison (3 x 10-16 at 200 s) is used to make

  12. Development and tests of x-ray multifoil optical system for 1D imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Pína, Ladislav; Hudec, René; Inneman, Adolf J.; Baca, Tomas; Blazek, M.; Platkevic, M.; Sieger, Ladislav; Doubravova, Daniela; McEntaffer, Randall L.; Schultz, Ted B.; Dániel, Vladimír.

    2016-09-01

    The proposed wide-field optical system has not been used yet. Described novel approach is based on the use of 1D "Lobster eye" optics in combination with Timepix X-ray detector in the energy range 3 - 40 keV. The proposed project includes theoretical study and a functional sample of the Timepix X-ray detector with multifoil wide-field X-ray "Lobster eye" optics. Using optics to focus X-rays on a detector is necessary in cases where the intensity of impinging X-ray radiation is below the sensitivity of the detector without optic. Generally this is the case of very low light phenomena, or e.g. monitoring astrophysical objects in space. Namely, such optical system could find applications in laboratory spectroscopy systems or in a rocket space experiment. Designed wide-field optical system combined with Timepix X-ray detector is described together with experimental results obtained during laboratory tests.

  13. Quantum simulation of decoherence in optical waveguide lattices.

    PubMed

    Longhi, Stefano

    2013-11-15

    We suggest that propagation of nonclassical light in lattices of optical waveguides can provide a laboratory tool to simulate quantum decoherence phenomena with high non-Markovian features. As examples, we study decoherence of optical Schrödinger cats in a lattice that mimics a dissipative quantum harmonic oscillator coupled to a quantum bath, showing fractional decoherence in the strong coupling regime, and Bloch oscillations of optical Schrödinger cats, where damped revivals of the coherence can be observed.

  14. Lattice gaugefixing and other optics in lattice gauge theory

    SciTech Connect

    Yee, Ken.

    1992-06-01

    We present results from four projects. In the first, quark and gluon propagators and effective masses and {Delta}I = 1/2 Rule operator matching coefficients are computed numerically in gaugefixed lattice QCD. In the second, the same quantities are evaluated analytically in the strong coupling, N {yields} {infinity} limit. In the third project, the Schwinger model is studied in covariant gauges, where we show that the effective electron mass varies with the gauge parameter and that longitudinal gaugefixing ambiguities affect operator product expansion coefficients (analogous to {Delta}I = 1/2 Rule matching coefficients) determined by matching gauge variant matrix elements. However, we find that matching coefficients even if shifted by the unphysical modes are {xi} invariant. In the fourth project, we show that the strong coupling parallelogram lattice Schwinger model as a different thermodynamic limit than the weak coupling continuum limit. As a function of lattice skewness angle these models span the {Delta} = {minus}1 critical line of 6-vertex models which, in turn, have been identified as c = 1 conformal field theories.

  15. Strongly Interacting Fermions in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Koetsier, A. O.

    2009-07-01

    presented here concerns fermionic atoms in periodic potential formed by interfering laser beams. Indeed, the standing light wave created by the interfering beams gives rise to a lattice potential because of the Stark effect which couples the electronic energy levels of the atoms to the spatially undulating electric field. Furthermore, fermionic atoms can be prepared in two different hyperfine states corresponding to the the spin-up and spin-down quantum states, and as such mimic electrons moving in the lattice structure of solids. This system is well described by the famous Hubbard model which we introduce in chapter 2 and, under certain conditions, undergoes a phase transition into the Néel state which believed to be a precursor to superconductivity in certain high-temperature superconductors. In chapter 3, we calculate precisely how the Néel state may be achieved in an ultracold fermionic atom gas. When the number of spin-up and spin-down atoms is unequal the system becomes spin-canted and exhibits both ferro- and antiferromagnetic characteristics, as we show in chapter 4. We also find there are topological excitations present in the quantum spin texture known as merons which have never unambiguously been observed before. In order to form a Bose-Einstein condensate, fermionic atoms must first form pairs, and can do so in two contrasting ways. The relationship between these two qualitatively di erent forms of pairing is described in chapter 5, and we examine how these two types of pairs transform into one another in an optical lattice in chapter 6. Finally, chapter 7 is a detailed eld-theoretic study of pairing as it occurs in an ultracold Bose gas. There, we find there is an intriguing bosonic analogy of the two forms of fermion pairing and explore the properties of these pairs.

  16. Estimating strong correlations in optical lattices

    NASA Astrophysics Data System (ADS)

    Gertis, J.; Friesdorf, M.; Riofrío, C. A.; Eisert, J.

    2016-11-01

    Ultracold atoms in optical lattices provide one of the most promising platforms for analog quantum simulations of complex quantum many-body systems. Large-size systems can now routinely be reached and are already used to probe a large variety of different physical situations, ranging from quantum phase transitions to artificial gauge theories. At the same time, measurement techniques are still limited and full tomography for these systems seems out of reach. Motivated by this observation, we present a method to directly detect and quantify to what extent a quantum state deviates from a local Gaussian description, based on available noise correlation measurements from in situ and time-of-flight measurements. This is an indicator of the significance of strong correlations in ground and thermal states, as Gaussian states are precisely the ground and thermal states of noninteracting models. We connect our findings, augmented by numerical tensor network simulations, to notions of equilibration, disordered systems, and the suppression of transport in Anderson insulators.

  17. Collisional Losses, Decoherence, and Frequency Shifts in Optical Lattice Clocks with Bosons

    SciTech Connect

    Lisdat, Ch.; Winfred, J. S. R. Vellore; Middelmann, T.; Riehle, F.; Sterr, U.

    2009-08-28

    We have quantified collisional losses, decoherence and the collision shift in a one-dimensional optical lattice clock on the highly forbidden transition {sup 1}S{sub 0}-{sup 3}P{sub 0} at 698 nm with bosonic {sup 88}Sr. We were able to distinguish two loss channels: inelastic collisions between atoms in the upper and lower clock state and atoms in the upper clock state only. Based on the measured coefficients, we determine the operation parameters at which a 1D-lattice clock with {sup 88}Sr shows no degradation due to collisions on the fractional uncertainty level of 10{sup -16}.

  18. Structural Phase Transitions of Vortex Matter in an Optical Lattice

    SciTech Connect

    Pu, H.; Yi, S.; Baksmaty, L.O.; Bigelow, N.P.

    2005-05-20

    We consider the vortex structure of a rapidly rotating trapped atomic Bose-Einstein condensate in the presence of a corotating periodic optical lattice potential. We observe a rich variety of structural phases which reflect the interplay of the vortex-vortex and vortex-lattice interactions. The lattice structure is very sensitive to the ratio of vortices to pinning sites and we observe structural phase transitions and domain formation as this ratio is varied.

  19. Progress towards a permanent electron electric dipole moment search using cold atoms in an optical lattice

    NASA Astrophysics Data System (ADS)

    Solmeyer, Neal E.; Zhu, Kunyan; Weiss, David S.

    2011-05-01

    Observation of a permanent electric dipole moment of the electron would imply CP violating effects not contained in the Standard Model. We present our progress towards measuring the electron EDM using laser-cooled cesium and rubidium atoms trapped in a one dimensional optical lattice. We have collected Cs atoms in a MOT and have launched them 90 cm vertically using two cavity-enhanced optical lattice guides. In that region, which is suitable for measurement, we re-cooled and re-trapped the atoms with an overall transfer efficiency from the MOT of 50%. The two 1D lattice traps thread through three specially-coated glass electric field plates. Very low frequency Ramsey-like spectroscopy will be sensitive to an EDM with an ultimate precision of 3 ×10-30 e-cm.

  20. Comment on 'Feshbach resonances in an optical lattice'

    SciTech Connect

    Diener, Roberto B.; Ho, T.-L.

    2006-01-15

    We point out some logical inconsistencies in the model proposed in [Phys. Rev. A 71, 043604 (2005)] as well as in the calculations performed on it. The proposed model is not able to describe Feshbach resonances in optical lattices.

  1. Matter-wave localization in a weakly perturbed optical lattice

    SciTech Connect

    Cheng, Yongshan; Adhikari, S. K.

    2011-11-15

    By numerical solution and variational approximation of the Gross-Pitaevskii equation, we studied the localization of a noninteracting and weakly interacting Bose-Einstein condensate in a weakly perturbed optical lattice in one and three dimensions. The perturbation achieved through a weak delocalizing expulsive or a linear potential as well as a weak localizing harmonic potential removes the periodicity of the optical lattice and leads to localization. We also studied some dynamics of the localized state confirming its stability.

  2. Light-induced atomic elevator in optical lattices

    NASA Astrophysics Data System (ADS)

    Prants, S. V.

    2016-12-01

    It is shown how an atomic elevator that can elevate falling cold atoms in a vertical optical lattice can be created. The effect appears near resonance owing to the nonlinear interaction between the electronic and mechanical degrees of freedom of an atom, which is responsible for its random walk in rigid optical lattices without any modulation and additional action. Numerical experiments involving spontaneous emission demonstrate that random walk of atoms and light-induced atomic elevator can be observed in a real experiment.

  3. Observation of Photon-Assisted Tunneling in Optical Lattices

    SciTech Connect

    Sias, C.; Lignier, H.; Singh, Y. P.; Zenesini, A.; Ciampini, D.; Morsch, O.; Arimondo, E.

    2008-02-01

    We have observed tunneling suppression and photon-assisted tunneling of Bose-Einstein condensates in an optical lattice subjected to a constant force plus a sinusoidal shaking. For a sufficiently large constant force, the ground energy levels of the lattice are shifted out of resonance and tunneling is suppressed; when the shaking is switched on, the levels are coupled by low-frequency photons and tunneling resumes. Our results agree well with theoretical predictions and demonstrate the usefulness of optical lattices for studying solid-state phenomena.

  4. Realizing type-II Weyl points in an optical lattice

    NASA Astrophysics Data System (ADS)

    Shastri, Kunal; Yang, Zhaoju; Zhang, Baile

    2017-01-01

    The recent discovery of the Lorentz symmetry-violating "type-II" Weyl semimetal phase has renewed interest in the study of Weyl physics in condensed-matter systems. However, tuning the exceptional properties of this novel state has remained a challenge. Optical lattices, created using standing laser beams, provide a convenient platform to tune tunneling parameters continuously in time. In this paper, we propose a generalized two level system exhibiting type-II Weyl points that can be realized using ultracold atoms in an optical lattice. The system is engineered using a three-dimensional lattice with complex π phase tunneling amplitudes. Various unique properties of the type-II Weyl semimetal such as open Fermi surface, anomalous chirality, and topological Fermi arcs can be probed using the proposed optical lattice scheme.

  5. Adiabatic dynamics with classical noise in optical lattice

    NASA Astrophysics Data System (ADS)

    Xu, Guanglei; Daley, Andrew

    2016-05-01

    The technique of adiabatic state preparation is an interesting potential tool for the realisation of sensitive many-body states with ultra-cold atoms at low temperatures. However, questions remain regarding the influence of classical noise in these adiabatic dynamics. We investigate such dynamics in a situation where a level dressing scheme can make amplitude noise in an optical lattice proportional to the Hamiltonian, leading to a quantum Zeno effect for non-adiabatic transitions. We compute the dynamics using stochastic many-body Schrödinger equation and master equation approaches. Taking the examples of 1D Bose-Hubbard model from Mott insulator phase to superfluid phase and comparing with analytical calculations for a two-level system, we demonstrate that when the total time for the process is limited, properly transformed noise can lead to an increased final fidelity in the state preparation. We consider the dynamics also in the presence of imperfections, studying the resulting heating and dephasing for the many-body states, and identifying optimal regimes for future experiments.

  6. Progress towards spin entanglement of cold atoms in double optical lattices

    NASA Astrophysics Data System (ADS)

    Wu, Jinwei; Hausmann, Marc; Vieira, David J.; Zhao, Xinxin

    2003-05-01

    Quantum entanglement of atoms is of fundamental interest in our understanding of quantum mechanics and it also plays a significant role in quantum information. One interesting candidate for achieving entanglement is cold neutral atoms in an optical lattice. Proposals to date include entangling atoms and realizing quantum logic gates via dipole-dipole interactions or cold collisions[1, 2, 3, 4]. At Los Alamos we have been setting up an optical lattice experiment to study m-state entanglement of ^87Rb atoms. We have pre-cooled the atoms in a MOT and setup a CO2-laser optical dipole trap. We plan to transfer the atoms into a 1D "storage lattice" formed by CO2 laser with a lattice constant of 5.3 μm and prepare the atoms into (F=2, m_F=1,2) states using optical pumping and Raman coupling. We will then adiabatically transfer the atoms to another shorter wavelength lattice with a much smaller lattice constant of ˜ 0.5 μm to entangle the atoms via the spin-spin interaction with an EPR entanglement rate of 0.2 Hz. After the entanglement, the atoms will be adiabatically transferred back to the "storage lattice" where they are readout using laser-induced fluorescence in the presence of a weak magnetic field gradient. We will present our latest progress towards the realization of neutral atom spin entanglement experiment. [1] G. K. Brennen, C. M. Caves, P. S. Jessen and I. H. Deutsch, Phys. Rev. Lett. 82, 1060 (1999). [2] D. Jaksch, H.-J. Briegel, J. I. Cirac, C. W. Gardiner and P. Zoller, Phys. Rev. Lett. 82, 1975 (1999). [3] D. Jaksch, J. I. Cirac, P. Zoller, S. L. Rolston, R. Cote and M. D. Lukin, Phys. Rev. Lett. 85, 2208 (2000). [4] L. You, and M. S. Chapman, Phys. Rev. A 62, 052302 (2000).

  7. Neutral gas heating via non-resonant optical lattices

    NASA Astrophysics Data System (ADS)

    Cornella, Barry Michael

    The influence of intense optical lattices on atoms or molecules offers a particularly useful method for energy and momentum deposition into a non-resonant gas. In this investigation, a proof-of-concept experiment was conducted to validate high intensity pulsed optical lattices as a means of creating high temperature gases for a myriad of aerospace, basic physics, and nanotechnology applications. Traditional methods for creating these flows have either involved altering the chemical composition of the initial gas sample through combustion or ionization or relied on laser resonant interactions with internal energy modes through laser pyrolysis. Due to its non-resonant nature, the use of optical lattices might be beneficial compared to existing methods since it provides an arbitrary, localized, high temperature gas that is tunable and does not introduce unwanted chemical species or high ionization concentrations. As an intermediate step toward verifying optical lattice gas heating, a coherent Rayleigh-Brillouin scattering (CRBS) study was also performed to verify the presented methodology. CRBS is a gas diagnostic technique used for non-intrusive probing of gas thermodynamic properties. In addition to the experimental investigation, a complementary numerical study was conducted using a direct simulation Monte Carlo approach. The numerical study used a modified version of SMILE to predict the gas phenomena within the strong optical potential fields. The goal of substantiating optical lattice heating was accomplished by detecting the acoustic wave generated from the heated volume. The magnitude of the resulting acoustic wave was shown to vary with the optical lattice phase velocity, peaking on the order of the gas' most probable speed. The trend with lattice velocity is consistent with both theory and the numerical study and eliminates other possible heating mechanisms such as laser-induced ionization or molecular dissociation. Limitations for the investigated heating

  8. An Optical Lattice Clock with Spin 1/2 Atoms

    DTIC Science & Technology

    2012-01-01

    89 4.4 Vector Stark shift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90...ytterbium atoms The first proposal for an optical lattice clock called for spectroscopy of a narrow optical tran- sition in ultracold strontium atoms [40...Since then, experimental groups have begun researching not only strontium (Sr) [70, 71, 72, 73, 74], but also ytterbium (Yb) [75, 76, 77, 78, 79] and

  9. Optical lattice clocks towards the redefinition of the second

    NASA Astrophysics Data System (ADS)

    Bregolin, F.; Milani, G.; Pizzocaro, M.; Rauf, B.; Thoumany, P.; Levi, F.; Calonico, D.

    2017-05-01

    Nowadays atomic optical lattice clocks can perform frequency measurements with a fractional uncertainty at the 10-18 level in few hours of measurement, outperforming the best caesium (Cs) standards operated in the world. Since the definition of the unit of time is based on Cs, a worldwide debate about the need to promote the redefinition of the second on a optical reference is under-way. At INRIM (Istituto Nazionale di Ricerca Metrologica) we developed an optical lattice clock based on ytterbium atoms and compared it against a Cs fountain. These results are an important contribution to the debate.

  10. Optical and structural modeling of disclination lattices in carbonaceous mesophases.

    PubMed

    Gupta, Gaurav; Hwang, Dae Kun; Rey, Alejandro D

    2005-01-15

    An integrated microstructural and optical model for carbonaceous mesophases is developed and used to explain the principles that govern the formation and stability of experimentally observed disclination lattices. The model is able to capture the orientation features of disclination lattices, including the type and location of disclination lines, and the orientation field in the mesophase matrix. The optical model based on reflection polarized optical microscopy is able to replicate all the details observed in actual observations. The typical brush figures have the proper distribution, orientation, and intensity. The computational predictions offer science-based routes to create and control desirable material architectures based on carbonaceous mesophase-carbon fiber composites.

  11. Evolution of the Hofstadter butterfly in a tunable optical lattice

    NASA Astrophysics Data System (ADS)

    Oktel, Mehmet O.; Unal, Nur; Yilmaz, Firat

    Advances in realizing artificial gauge fields on optical lattices promise experimental detection of topologically non-trivial energy spectra. Self-similar fractal energy structures, known as Hofstadter butterflies, depend sensitively on the geometry of the lattice, as well as the applied magnetic field. The recent demonstration of an adjustable lattice geometry [L. Tarruell et al., Nature 483, 302 (2012)] presents a unique opportunity to study this dependence. We calculate the Hofstadter butterflies that can be obtained in such an adjustable lattice and find three qualitatively different regimes. We show that the existence of Dirac points at zero magnetic field does not imply the topological equivalence of spectra at finite field. As the real-space structure evolves from the checkerboard to the honeycomb lattice, two square lattice Hofstadter butterflies merge to form a honeycomb lattice butterfly in a topologically non-trivial way, as it is accomplished by sequential closing of infinitely many gaps. We discuss the evolution of topological properties with underlying lattice geometry by calculating the Chern numbers and comment on the validity of simulating graphene in such an adjustable lattice

  12. Ultracold polar molecules in a 3D optical lattice

    NASA Astrophysics Data System (ADS)

    Yan, Bo

    2015-05-01

    Ultracold polar molecules, with their long-range electric dipolar interactions, offer new opportunities for studying quantum magnetism and many-body physics. KRb molecules loaded into a three-dimensional (3D) optical lattice allow one to study such a spin-lattice system in a stable environment without losses arising from chemical reactions. In the case with strong lattice confinement along two directions and a weak lattice potential along the third, we find the loss rate is suppressed by the quantum Zeno effect. In a deep 3D lattice with no tunneling, we observe evidences for spin exchange interactions. We use Ramsey spectroscopy to investigate the spin dynamics. By choosing the appropriate lattice polarizations and implementing a spin echo sequence, the single particle dephasing is largely suppressed, leaving the dipolar exchange interactions as the dominant contribution to the observed dynamics. This is supported by many-body theoretical calculations. While this initial demonstration was done with low lattice fillings, our current experimental efforts are focused on increasing the lattice filling fraction. This will greatly benefit the study of complex many-body dynamics with long-range interactions, such as transport of excitations in an out-of-equilibrium system and spin-orbit coupling in a lattice.

  13. Quantum simulation of 2D topological physics in a 1D array of optical cavities.

    PubMed

    Luo, Xi-Wang; Zhou, Xingxiang; Li, Chuan-Feng; Xu, Jin-Shi; Guo, Guang-Can; Zhou, Zheng-Wei

    2015-07-06

    Orbital angular momentum of light is a fundamental optical degree of freedom characterized by unlimited number of available angular momentum states. Although this unique property has proved invaluable in diverse recent studies ranging from optical communication to quantum information, it has not been considered useful or even relevant for simulating nontrivial physics problems such as topological phenomena. Contrary to this misconception, we demonstrate the incredible value of orbital angular momentum of light for quantum simulation by showing theoretically how it allows to study a variety of important 2D topological physics in a 1D array of optical cavities. This application for orbital angular momentum of light not only reduces required physical resources but also increases feasible scale of simulation, and thus makes it possible to investigate important topics such as edge-state transport and topological phase transition in a small simulator ready for immediate experimental exploration.

  14. Quantum simulation of 2D topological physics in a 1D array of optical cavities

    PubMed Central

    Luo, Xi-Wang; Zhou, Xingxiang; Li, Chuan-Feng; Xu, Jin-Shi; Guo, Guang-Can; Zhou, Zheng-Wei

    2015-01-01

    Orbital angular momentum of light is a fundamental optical degree of freedom characterized by unlimited number of available angular momentum states. Although this unique property has proved invaluable in diverse recent studies ranging from optical communication to quantum information, it has not been considered useful or even relevant for simulating nontrivial physics problems such as topological phenomena. Contrary to this misconception, we demonstrate the incredible value of orbital angular momentum of light for quantum simulation by showing theoretically how it allows to study a variety of important 2D topological physics in a 1D array of optical cavities. This application for orbital angular momentum of light not only reduces required physical resources but also increases feasible scale of simulation, and thus makes it possible to investigate important topics such as edge-state transport and topological phase transition in a small simulator ready for immediate experimental exploration. PMID:26145177

  15. Three-dimensional optical lattice clock with bosonic {sup 88}Sr atoms

    SciTech Connect

    Akatsuka, Tomoya; Takamoto, Masao; Katori, Hidetoshi

    2010-02-15

    We present detailed analyses of our recent experiment on the three-dimensional (3D) optical lattice clock with bosonic {sup 88}Sr atoms in which the collisional frequency shift was suppressed by applying a single-occupancy lattice. Frequency shifts in magnetically induced spectroscopy on the {sup 1}S{sub 0}-{sup 3}P{sub 0} clock transition ({lambda}=698 nm) of {sup 88}Sr were experimentally investigated by referencing a one-dimensional (1D) lattice clock based on spin-polarized {sup 87}Sr atoms. We discuss that the clock stability is limited by the current laser stability as well as the experimental sequence of the clock operation, which may be improved to {sigma}{sub y}({tau})=2x10{sup -16}/{radical}({tau}) by optimizing the cycle time of the clock operation.

  16. Lattice-cavity solitons in a degenerate optical parametric oscillator

    SciTech Connect

    Egorov, O. A.; Lederer, F.

    2007-11-15

    We predict the existence of lattice-cavity solitons for a quadratic nonlinear cavity, where the linear losses are compensated for by the optical pump at second harmonic (degenerate optical parametric oscillator), and which is endowed with a one-dimensional photonic lattice. In the limit of strong discreteness (weak coupling) this kind of soliton solution contains as the subclass the quadratic discrete cavity solitons. The nonlinear coupling between the Bloch waves of different photonics bands allows for the formation of a reach variety of localized solutions. In particular, different types of multiband lattice-cavity solitons can be identified. Most types of lattice-cavity solitons do not have counterparts, neither in conventional planar microresonators nor in genuine discrete systems as an array of weakly coupled cavities. We show that these solitons may destabilize as a consequence of the competition between Bloch waves of different photonic bands.

  17. High-Field Fractional Quantum Hall Effect in Optical Lattices

    SciTech Connect

    Palmer, R.N.; Jaksch, D.

    2006-05-12

    We consider interacting bosonic atoms in an optical lattice subject to a large simulated magnetic field. We develop a model similar to a bilayer fractional quantum Hall system valid near simple rational numbers of magnetic flux quanta per lattice cell. Then we calculate its ground state, magnetic lengths, fractional fillings, and find unexpected sign changes in the Hall current. Finally we study methods for detecting these novel features via shot noise and Hall current measurements.

  18. Optical Lattice Simulations of Correlated Fermions

    DTIC Science & Technology

    2013-10-04

    Field, Rashba Spin -Orbit Coupled Quantum Gases C. J. Bolech at LPHYS󈧐, Dimensional Crossover and Geometric Quenches in 1D Polarized Attractive Fermi...gas with spin -imbalance in this way. This system features a partially polarized phase which is the 1D analog of the long-sought FFLO state. Current... quantum vortex state in a spin -orbit-coupled Bose-Einstein condensate, Physical Review A, (02 2012): 0. doi: 10.1103/PhysRevA.85.023606 08/16/2012 36.00

  19. Harnessing optical vortex lattices in nematic liquid crystals.

    PubMed

    Barboza, R; Bortolozzo, U; Assanto, G; Vidal-Henriquez, E; Clerc, M G; Residori, S

    2013-08-30

    By creating self-induced vortexlike defects in the nematic liquid crystal layer of a light valve, we demonstrate the realization of programable lattices of optical vortices with arbitrary distribution in space. On each lattice site, every matter vortex acts as a photonic spin-to-orbital momentum coupler and an array of circularly polarized input beams is converted into an output array of vortex beams with topological charges consistent with the matter lattice. The vortex arrangements are explained on the basis of light-induced matter defects of both signs and consistent topological rules.

  20. Controlled wave-packet manipulation with driven optical lattices

    SciTech Connect

    Arlinghaus, Stephan; Holthaus, Martin

    2011-12-15

    Motivated by recent experimental progress achieved with ultracold atoms in kilohertz-driven optical lattices, we provide a theoretical discussion of mechanisms governing the response of a particle in a cosine lattice potential to strong forcing pulses with smooth envelope. Such pulses effectuate adiabatic motion of a wave packet's momentum distribution on quasienergy surfaces created by spatiotemporal Bloch waves. Deviations from adiabaticity can then be deliberately exploited for exerting coherent control and for reaching target states which may not be accessible by other means. As one particular example, we consider an analog of the {pi} pulses known from optical resonance. We also suggest adapting further techniques previously developed for controlling atomic and molecular dynamics by laser pulses to the coherent control of matter waves in shaken optical lattices.

  1. Bloch-Zener oscillations in a tunable optical honeycomb lattice

    SciTech Connect

    Uehlinger, Thomas; Greif, Daniel; Jotzu, Gregor; Esslinger, Tilman; Tarruell, Leticia

    2013-12-04

    Ultracold gases in optical lattices have proved to be a flexible tool to simulate many different phenomena of solid state physics [1, 2]. Recently, optical lattices with complex geometries have been realized [3, 4, 5, 6, 7], paving the way to simulating more realistic systems. The honeycomb structure has recently become accessible in an optical lattice composed of mutually perpendicular laser beams. This lattice structure exhibits topological features in its band structure – the Dirac points. At these points, two energy bands intersect linearly and the particles behave as relativistic Dirac fermions. In optical lattices, Bloch oscillations [8] resolved both in time and in quasi-momentum space can be directly observed. We make use of such Bloch-Zener oscillations to probe the vanishing energy gap at the Dirac points as well as their position in the band structure. In small band gap regions, we observe Landau-Zener tunneling [7, 9] to the second band and the regions of maximum transfer can be identified with the position of the Dirac points.

  2. Quantum Entanglement in Optical Lattice Systems

    DTIC Science & Technology

    2015-02-18

    Hamner, Chunlei Qu, Yongping Zhang, JiaJia Chang, Ming Gong, Chuanwei Zhang, Peter Engels. Dicke -type phase transition in a spin-orbit-coupled Bose...coupled BECs, including studies of quench dynamics, Dicke -type physics, and spin-orbit coupled lattice systems. Our experiments were closely accompanied...published as a Rapid Communication in Physical Review A (PRA 88, 021604(R) (2013)). 2.) Dicke -type physics: Following our investigation of

  3. Coupled matter-wave solitons in optical lattices

    SciTech Connect

    Golam Ali, Sk; Talukdar, B.

    2009-06-15

    We make use of a potential model to study the dynamics of two coupled matter-wave or Bose-Einstein condensate (BEC) solitons loaded in optical lattices. With separate attention to linear and nonlinear lattices we find some remarkable differences for response of the system to effects of these lattices. As opposed to the case of linear optical lattice (LOL), the nonlinear lattice (NOL) can be used to control the mutual interaction between the two solitons. For a given lattice wave number k, the effective potentials in which the two solitons move are such that the well (V{sub eff}(NOL)), resulting from the juxtaposition of soliton interaction and nonlinear lattice potential, is deeper than the corresponding well V{sub eff}(LOL). But these effective potentials have opposite k dependence in the sense that the depth of V{sub eff}(LOL) increases as k increases and that of V{sub eff}(NOL) decreases for higher k values. We verify that the effectiveness of optical lattices to regulate the motion of the coupled solitons depends sensitively on the initial locations of the motionless solitons as well as values of the lattice wave number. For both LOL and NOL the two solitons meet each other due to mutual interaction if their initial locations are taken within the potential wells with the difference that the solitons in the NOL approach each other rather rapidly and take roughly half the time to meet as compared with the time needed for such coalescence in the LOL. In the NOL, the soliton profiles can move freely and respond to the lattice periodicity when the separation between their initial locations are as twice as that needed for a similar free movement in the LOL. We observe that, in both cases, slow tuning of the optical lattices by varying k with respect to a time parameter {tau} drags the oscillatory solitons apart to take them to different locations. In our potential model the oscillatory solitons appear to propagate undistorted. But a fully numerical calculation

  4. Coupled matter-wave solitons in optical lattices

    NASA Astrophysics Data System (ADS)

    Golam Ali, Sk; Talukdar, B.

    2009-06-01

    We make use of a potential model to study the dynamics of two coupled matter-wave or Bose-Einstein condensate (BEC) solitons loaded in optical lattices. With separate attention to linear and nonlinear lattices we find some remarkable differences for response of the system to effects of these lattices. As opposed to the case of linear optical lattice (LOL), the nonlinear lattice (NOL) can be used to control the mutual interaction between the two solitons. For a given lattice wave number k, the effective potentials in which the two solitons move are such that the well (Veff(NOL)), resulting from the juxtaposition of soliton interaction and nonlinear lattice potential, is deeper than the corresponding well Veff(LOL). But these effective potentials have opposite k dependence in the sense that the depth of Veff(LOL) increases as k increases and that of Veff(NOL) decreases for higher k values. We verify that the effectiveness of optical lattices to regulate the motion of the coupled solitons depends sensitively on the initial locations of the motionless solitons as well as values of the lattice wave number. For both LOL and NOL the two solitons meet each other due to mutual interaction if their initial locations are taken within the potential wells with the difference that the solitons in the NOL approach each other rather rapidly and take roughly half the time to meet as compared with the time needed for such coalescence in the LOL. In the NOL, the soliton profiles can move freely and respond to the lattice periodicity when the separation between their initial locations are as twice as that needed for a similar free movement in the LOL. We observe that, in both cases, slow tuning of the optical lattices by varying k with respect to a time parameter τ drags the oscillatory solitons apart to take them to different locations. In our potential model the oscillatory solitons appear to propagate undistorted. But a fully numerical calculation indicates that during evolution

  5. Physics of higher orbital bands in optical lattices: a review

    NASA Astrophysics Data System (ADS)

    Li, Xiaopeng; Liu, W. Vincent

    2016-11-01

    The orbital degree of freedom plays a fundamental role in understanding the unconventional properties in solid state materials. Experimental progress in quantum atomic gases has demonstrated that high orbitals in optical lattices can be used to construct quantum emulators of exotic models beyond natural crystals, where novel many-body states such as complex Bose-Einstein condensates and topological semimetals emerge. A brief introduction of orbital degrees of freedom in optical lattices is given and a summary of exotic orbital models and resulting many-body phases is provided. Experimental consequences of the novel phases are also discussed.

  6. Bose-Fermi mixtures in an optical lattice

    SciTech Connect

    Sengupta, K.; Majumdar, P.

    2007-06-15

    We study an atomic Bose-Fermi mixture with unpolarized fermions in an optical lattice. We obtain the Mott ground states of such a system in the limit of the deep optical lattice and discuss the effect of quantum fluctuations on these states. We also study the superfluid-insulator transitions of bosons and metal-insulator transition of fermions in such a mixture within a slave-rotor mean-field approximation, and obtain the corresponding phase diagram. We discuss experimental implications of our results.

  7. Physics of higher orbital bands in optical lattices: a review.

    PubMed

    Li, Xiaopeng; Liu, W Vincent

    2016-11-01

    The orbital degree of freedom plays a fundamental role in understanding the unconventional properties in solid state materials. Experimental progress in quantum atomic gases has demonstrated that high orbitals in optical lattices can be used to construct quantum emulators of exotic models beyond natural crystals, where novel many-body states such as complex Bose-Einstein condensates and topological semimetals emerge. A brief introduction of orbital degrees of freedom in optical lattices is given and a summary of exotic orbital models and resulting many-body phases is provided. Experimental consequences of the novel phases are also discussed.

  8. Resonant scattering and microscopic model of spinless Fermi gases in one-dimensional optical lattices

    NASA Astrophysics Data System (ADS)

    Cui, Xiaoling

    2017-04-01

    We study the effective Bloch-wave scattering of a spinless Fermi gas in one-dimensional (1D) optical lattices. By tuning the odd-wave scattering length, we find multiple resonances of Bloch waves scattering at the bottom (and the top) of the lowest band, beyond which an attractive (and a repulsive) two-body bound state starts to emerge. These resonances exhibit comparable widths in the deep lattice limit, and the finite interaction range plays an essential role in determining their locations. Based on exact two-body solutions, we construct an effective microscopic model for the low-energy scattering of fermions. The model can reproduce not only the scattering amplitudes of Bloch waves at the lowest-band bottom or top, but also the attractive or repulsive bound states within a reasonably large energy range below or above the band. These results lay the foundation for quantum simulating topological states in cold Fermi gases confined in 1D optical lattices.

  9. Triangular and honeycomb lattices of cold atoms in optical cavities

    NASA Astrophysics Data System (ADS)

    Safaei, Shabnam; Miniatura, Christian; Grémaud, Benoît.

    2015-10-01

    We consider a two-dimensional homogeneous ensemble of cold bosonic atoms loaded inside two optical cavities and pumped by a far-detuned external laser field. We examine the conditions for these atoms to self-organize into triangular and honeycomb lattices as a result of superradiance. By collectively scattering the pump photons, the atoms feed the initially empty cavity modes. As a result, the superposition of the pump and cavity fields creates a space-periodic light-shift external potential and atoms self-organize into the potential wells of this optical lattice. Depending on the phase of the cavity fields with respect to the pump laser, these minima can either form a triangular or a hexagonal lattice. By numerically solving the dynamical equations of the coupled atom-cavity system, we have shown that the two stable atomic structures at long times are the triangular lattice and the honeycomb lattice with equally populated sites. We have also studied how to drive atoms from one lattice structure to another by dynamically changing the phase of the cavity fields with respect to the pump laser.

  10. Different models of gravitating Dirac fermions in optical lattices

    NASA Astrophysics Data System (ADS)

    Celi, Alessio

    2017-07-01

    In this paper I construct the naive lattice Dirac Hamiltonian describing the propagation of fermions in a generic 2D optical metric for different lattice and flux-lattice geometries. First, I apply a top-down constructive approach that we first proposed in [Boada et al., New J. Phys. 13, 035002 (2011)] to the honeycomb and to the brickwall lattices. I carefully discuss how gauge transformations that generalize momentum (and Dirac cone) shifts in the Brillouin zone in the Minkowski homogeneous case can be used in order to change the phases of the hopping. In particular, I show that lattice Dirac Hamiltonian for Rindler spacetime in the honeycomb and brickwall lattices can be realized by considering real and isotropic (but properly position dependent) tunneling terms. For completeness, I also discuss a suitable formulation of Rindler Dirac Hamiltonian in semi-synthetic brickwall and π-flux square lattices (where one of the dimension is implemented by using internal spin states of atoms as we originally proposed in [Boada et al., Phys. Rev. Lett. 108, 133001 (2012)] and [Celi et al., Phys. Rev. Lett. 112, 043001 (2014)]).

  11. Stability of matter-wave solitons in optical lattices

    NASA Astrophysics Data System (ADS)

    Ali, Sk. Golam; Roy, S. K.; Talukdar, B.

    2010-08-01

    We consider localized states of both single- and two-component Bose-Einstein condensates (BECs) confined in a potential resulting from the superposition of linear and nonlinear optical lattices and make use of Vakhitov-Kolokolov criterion to investigate the effect of nonlinear lattice on the stability of the soliton solutions in the linear optical lattice (LOL). For the single-component case we show that a weak nonlinear lattice has very little effect on the stability of such solitons while sufficiently strong nonlinear optical lattice (NOL) squeezes them to produce narrow bound states. For two-component condensates we find that when the strength of the NOL (γ1) is less than that of the LOL (V0) a relatively weak intra-atomic interaction (IAI) has little effect on the stability of the component solitons. This is true for both attractive and repulsive IAI. A strong attractive IAI, however, squeezes the BEC solitons while a similar repulsive IAI makes the component solitons wider. For γ1 > V0, only a strong attractive IAI squeezes the BEC solitons but the squeezing effect is less prominent than that found for γ1 < V0. We make useful checks on the results of our semianalytical stability analysis by solving the appropriate Gross-Pitaevskii equations numerically.

  12. Mixtures of bosonic and fermionic atoms in optical lattices

    SciTech Connect

    Albus, Alexander; Illuminati, Fabrizio; Eisert, Jens

    2003-08-01

    We discuss the theory of mixtures of bosonic and fermionic atoms in periodic potentials at zero temperature. We derive a general Bose-Fermi Hubbard Hamiltonian in a one-dimensional optical lattice with a superimposed harmonic trapping potential. We study the conditions for linear stability of the mixture and derive a mean-field criterion for the onset of a bosonic superfluid transition. We investigate the ground-state properties of the mixture in the Gutzwiller formulation of mean-field theory, and present numerical studies of finite systems. The bosonic and fermionic density distributions and the onset of quantum phase transitions to demixing and to a bosonic Mott-insulator are studied as a function of the lattice potential strength. The existence is predicted of a disordered phase for mixtures loaded in very deep lattices. Such a disordered phase possessing many degenerate or quasidegenerate ground states is related to a breaking of the mirror symmetry in the lattice.

  13. Optical lattice polarization effects on magnetically induced optical atomic clock transitions

    SciTech Connect

    Taichenachev, A. V.; Yudin, V. I.; Oates, C. W.

    2007-08-15

    We derive the frequency shift for a forbidden optical transition J=0{yields}J{sup '}=0 caused by the simultaneous actions of an elliptically polarized lattice field and a static magnetic field. We find that a simple configuration of lattice and magnetic fields leads to a cancellation of this shift to first order in lattice intensity and magnetic field. In this geometry, the second-order lattice intensity shift can be minimized as well by use of optimal lattice polarization. Suppression of these shifts could considerably enhance the performance of the next generation of atomic clocks.

  14. Veselago lensing with ultracold atoms in an optical lattice

    NASA Astrophysics Data System (ADS)

    Leder, Martin; Grossert, Christopher; Weitz, Martin

    2014-02-01

    Veselago pointed out that electromagnetic wave theory allows for materials with a negative index of refraction, in which most known optical phenomena would be reversed. A slab of such a material can focus light by negative refraction, an imaging technique strikingly different from conventional positive refractive index optics, where curved surfaces bend the rays to form an image of an object. Here we demonstrate Veselago lensing for matter waves, using ultracold atoms in an optical lattice. A relativistic, that is, photon-like, dispersion relation for rubidium atoms is realized with a bichromatic optical lattice potential. We rely on a Raman π-pulse technique to transfer atoms between two different branches of the dispersion relation, resulting in a focusing that is completely analogous to the effect described by Veselago for light waves. Future prospects of the demonstrated effects include novel sub-de Broglie wavelength imaging applications.

  15. Veselago lensing with ultracold atoms in an optical lattice

    NASA Astrophysics Data System (ADS)

    Leder, Martin; Grossert, Christopher; Weitz, Martin

    2014-05-01

    Veselago pointed out that electromagnetic theory allows for materials with a negative index of refraction, in which most known optical phenomena are reversed. A slab of such a material can focus light by negative refraction, an imaging technique strikingly different from conventional positive refractive index optics, where curved surfaces bend the rays to form an image of an object. Here we demonstrate Veselago lensing for matter waves, using ultracold atoms in an optical lattice. A relativistic, i.e. photon-like, dispersion relation for rubidium atoms is realized with a bichromatic optical lattice potential. A Raman pi-pulse technique serves to transfer atoms between two different branches of the dispersion relation, and the relativistic lensing occurs by a backwards propagation of atomic wavepackets on an energetically mirrored branch of the dispersion relation. We observe negative refraction and Veselago lensing both in a one-dimensional geometry and perform a ray-tracing simulation of a two-dimensional Veselago lens.

  16. Veselago lensing with ultracold atoms in an optical lattice.

    PubMed

    Leder, Martin; Grossert, Christopher; Weitz, Martin

    2014-01-01

    Veselago pointed out that electromagnetic wave theory allows for materials with a negative index of refraction, in which most known optical phenomena would be reversed. A slab of such a material can focus light by negative refraction, an imaging technique strikingly different from conventional positive refractive index optics, where curved surfaces bend the rays to form an image of an object. Here we demonstrate Veselago lensing for matter waves, using ultracold atoms in an optical lattice. A relativistic, that is, photon-like, dispersion relation for rubidium atoms is realized with a bichromatic optical lattice potential. We rely on a Raman π-pulse technique to transfer atoms between two different branches of the dispersion relation, resulting in a focusing that is completely analogous to the effect described by Veselago for light waves. Future prospects of the demonstrated effects include novel sub-de Broglie wavelength imaging applications.

  17. Strongly interacting bosons in a disordered optical lattice.

    PubMed

    White, M; Pasienski, M; McKay, D; Zhou, S Q; Ceperley, D; Demarco, B

    2009-02-06

    We experimentally probe the properties of the disordered Bose-Hubbard model using an atomic Bose-Einstein condensate trapped in a 3D disordered optical lattice. Controllable disorder is introduced using a fine-grained optical speckle field with features comparable in size to the lattice spacing along every lattice direction. A precision measurement of the disordering potential is used to compute the single-particle parameters of the system. To constrain theories of the disordered Bose Hubbard model, we have measured the change in condensate fraction as a function of disorder strength for several different ratios of tunneling to interaction energy. We observe disorder-induced, reversible suppression of condensate fraction for superfluid and coexisting superfluid-Mott-insulator phases.

  18. Collisional shifts in optical-lattice atom clocks

    SciTech Connect

    Band, Y. B.; Vardi, A.

    2006-09-15

    We theoretically study the effects of elastic collisions on the determination of frequency standards via Ramsey-fringe spectroscopy in optical-lattice atom clocks. Interparticle interactions of bosonic atoms in multiply occupied lattice sites can cause a linear frequency shift, as well as generate asymmetric Ramsey-fringe patterns and reduce fringe visibility due to interparticle entanglement. We propose a method of reducing these collisional effects in an optical lattice by introducing a phase difference of {pi} between the Ramsey driving fields in adjacent sites. This configuration suppresses site-to-site hopping due to interference of two tunneling pathways, without degrading fringe visibility. Consequently, the probability of double occupancy is reduced, leading to cancellation of collisional shifts.

  19. Optical lattice polarization effects on hyperpolarizability of atomic clock transitions.

    PubMed

    Taichenachev, A V; Yudin, V I; Ovsiannikov, V D; Pal'chikov, V G

    2006-10-27

    The light-induced frequency shift due to hyperpolarizability (i.e., terms of second-order in intensity) is studied for a forbidden optical transition, J = 0 --> J = 0. A simple universal dependence on the field ellipticity is obtained. This result allows minimization of the second-order light shift with respect to the field polarization for optical lattices operating at a magic wavelength (at which the first-order shift vanishes). We show the possibility for the existence of a magic elliptical polarization, for which the second-order frequency shift vanishes. The optimal polarization of the lattice field can be either linear, circular, or magic elliptical. The obtained results could improve the accuracy of lattice-based atomic clocks.

  20. Reply to ``Comment on `Feshbach resonances in an optical lattice' ''

    NASA Astrophysics Data System (ADS)

    Dickerscheid, D. B. M.; van Oosten, D.; Stoof, H. T. C.

    2006-01-01

    We show that the Comment by Diener and Ho [Phys. Rev. A 73, 017601 (2006)] is based on the misunderstanding that the Hamiltonian used by Dickerscheid to describe Feshbach resonances in an optical lattice is a microscopic Hamiltonian as opposed to an effective Hamiltonian.

  1. Reply to 'Comment on 'Feshbach resonances in an optical lattice''

    SciTech Connect

    Dickerscheid, D. B. M.; Stoof, H. T. C.; Oosten, D. van

    2006-01-15

    We show that the Comment by Diener and Ho [Phys. Rev. A 73, 017601 (2006)] is based on the misunderstanding that the Hamiltonian used by Dickerscheid et al. to describe Feshbach resonances in an optical lattice is a microscopic Hamiltonian as opposed to an effective Hamiltonian.

  2. An approach to control tuning range and speed in 1D ternary photonic band gap material nano-layered optical filter structures electro-optically

    SciTech Connect

    Zia, Shahneel Banerjee, Anirudh

    2016-05-06

    This paper demonstrates a way to control spectrum tuning capability in one-dimensional (1D) ternary photonic band gap (PBG) material nano-layered structures electro-optically. It is shown that not only tuning range, but also tuning speed of tunable optical filters based on 1D ternary PBG structures can be controlled Electro-optically. This approach finds application in tuning range enhancement of 1D Ternary PBG structures and compensating temperature sensitive transmission spectrum shift in 1D Ternary PBG structures.

  3. Pressure sensor via optical detection based on a 1D spin transition coordination polymer.

    PubMed

    Jureschi, Cătălin M; Linares, Jorge; Rotaru, Aurelian; Ritti, Marie Hélène; Parlier, Michel; Dîrtu, Marinela M; Wolff, Mariusz; Garcia, Yann

    2015-01-22

    We have investigated the suitability of using the 1D spin crossover coordination polymer [Fe(4-(2'-hydroxyethyl)-1,2,4-triazole)3]I2∙H2O, known to crossover around room temperature, as a pressure sensor via optical detection using various contact pressures up to 250 MPa. A dramatic persistent colour change is observed. The experimental data, obtained by calorimetric and Mössbauer measurements, have been used for a theoretical analysis, in the framework of the Ising-like model, of the thermal and pressure induced spin state switching. The pressure (P)-temperature (T) phase diagram calculated for this compound has been used to obtain the P-T bistability region.

  4. Pressure Sensor via Optical Detection Based on a 1D Spin Transition Coordination Polymer

    PubMed Central

    Jureschi, Cătălin M.; Linares, Jorge; Rotaru, Aurelian; Ritti, Marie Hélène; Parlier, Michel; Dîrtu, Marinela M.; Wolff, Mariusz; Garcia, Yann

    2015-01-01

    We have investigated the suitability of using the 1D spin crossover coordination polymer [Fe(4-(2′-hydroxyethyl)-1,2,4-triazole)3]I2·H2O, known to crossover around room temperature, as a pressure sensor via optical detection using various contact pressures up to 250 MPa. A dramatic persistent colour change is observed. The experimental data, obtained by calorimetric and Mössbauer measurements, have been used for a theoretical analysis, in the framework of the Ising-like model, of the thermal and pressure induced spin state switching. The pressure (P)-temperature (T) phase diagram calculated for this compound has been used to obtain the P-T bistability region. PMID:25621610

  5. Superfluid qubit systems with ring shaped optical lattices

    PubMed Central

    Amico, Luigi; Aghamalyan, Davit; Auksztol, Filip; Crepaz, Herbert; Dumke, Rainer; Kwek, Leong Chuan

    2014-01-01

    We study an experimentally feasible qubit system employing neutral atomic currents. Our system is based on bosonic cold atoms trapped in ring-shaped optical lattice potentials. The lattice makes the system strictly one dimensional and it provides the infrastructure to realize a tunable ring-ring interaction. Our implementation combines the low decoherence rates of neutral cold atoms systems, overcoming single site addressing, with the robustness of topologically protected solid state Josephson flux qubits. Characteristic fluctuations in the magnetic fields affecting Josephson junction based flux qubits are expected to be minimized employing neutral atoms as flux carriers. By breaking the Galilean invariance we demonstrate how atomic currents through the lattice provide an implementation of a qubit. This is realized either by artificially creating a phase slip in a single ring, or by tunnel coupling of two homogeneous ring lattices. The single qubit infrastructure is experimentally investigated with tailored optical potentials. Indeed, we have experimentally realized scaled ring-lattice potentials that could host, in principle, n ~ 10 of such ring-qubits, arranged in a stack configuration, along the laser beam propagation axis. An experimentally viable scheme of the two-ring-qubit is discussed, as well. Based on our analysis, we provide protocols to initialize, address, and read-out the qubit. PMID:24599096

  6. Superfluid qubit systems with ring shaped optical lattices.

    PubMed

    Amico, Luigi; Aghamalyan, Davit; Auksztol, Filip; Crepaz, Herbert; Dumke, Rainer; Kwek, Leong Chuan

    2014-03-06

    We study an experimentally feasible qubit system employing neutral atomic currents. Our system is based on bosonic cold atoms trapped in ring-shaped optical lattice potentials. The lattice makes the system strictly one dimensional and it provides the infrastructure to realize a tunable ring-ring interaction. Our implementation combines the low decoherence rates of neutral cold atoms systems, overcoming single site addressing, with the robustness of topologically protected solid state Josephson flux qubits. Characteristic fluctuations in the magnetic fields affecting Josephson junction based flux qubits are expected to be minimized employing neutral atoms as flux carriers. By breaking the Galilean invariance we demonstrate how atomic currents through the lattice provide an implementation of a qubit. This is realized either by artificially creating a phase slip in a single ring, or by tunnel coupling of two homogeneous ring lattices. The single qubit infrastructure is experimentally investigated with tailored optical potentials. Indeed, we have experimentally realized scaled ring-lattice potentials that could host, in principle, n ~ 10 of such ring-qubits, arranged in a stack configuration, along the laser beam propagation axis. An experimentally viable scheme of the two-ring-qubit is discussed, as well. Based on our analysis, we provide protocols to initialize, address, and read-out the qubit.

  7. Doublon dynamics and polar molecule production in an optical lattice.

    PubMed

    Covey, Jacob P; Moses, Steven A; Gärttner, Martin; Safavi-Naini, Arghavan; Miecnikowski, Matthew T; Fu, Zhengkun; Schachenmayer, Johannes; Julienne, Paul S; Rey, Ana Maria; Jin, Deborah S; Ye, Jun

    2016-04-14

    Polar molecules in an optical lattice provide a versatile platform to study quantum many-body dynamics. Here we use such a system to prepare a density distribution where lattice sites are either empty or occupied by a doublon composed of an interacting Bose-Fermi pair. By letting this out-of-equilibrium system evolve from a well-defined, but disordered, initial condition, we observe clear effects on pairing that arise from inter-species interactions, a higher partial-wave Feshbach resonance and excited Bloch-band population. These observations facilitate a detailed understanding of molecule formation in the lattice. Moreover, the interplay of tunnelling and interaction of fermions and bosons provides a controllable platform to study Bose-Fermi Hubbard dynamics. Additionally, we can probe the distribution of the atomic gases in the lattice by measuring the inelastic loss of doublons. These techniques realize tools that are generically applicable to studying the complex dynamics of atomic mixtures in optical lattices.

  8. Doublon dynamics and polar molecule production in an optical lattice

    PubMed Central

    Covey, Jacob P.; Moses, Steven A.; Gärttner, Martin; Safavi-Naini, Arghavan; Miecnikowski, Matthew T.; Fu, Zhengkun; Schachenmayer, Johannes; Julienne, Paul S.; Rey, Ana Maria; Jin, Deborah S.; Ye, Jun

    2016-01-01

    Polar molecules in an optical lattice provide a versatile platform to study quantum many-body dynamics. Here we use such a system to prepare a density distribution where lattice sites are either empty or occupied by a doublon composed of an interacting Bose-Fermi pair. By letting this out-of-equilibrium system evolve from a well-defined, but disordered, initial condition, we observe clear effects on pairing that arise from inter-species interactions, a higher partial-wave Feshbach resonance and excited Bloch-band population. These observations facilitate a detailed understanding of molecule formation in the lattice. Moreover, the interplay of tunnelling and interaction of fermions and bosons provides a controllable platform to study Bose-Fermi Hubbard dynamics. Additionally, we can probe the distribution of the atomic gases in the lattice by measuring the inelastic loss of doublons. These techniques realize tools that are generically applicable to studying the complex dynamics of atomic mixtures in optical lattices. PMID:27075831

  9. Super-resolution microscopy of single atoms in optical lattices

    NASA Astrophysics Data System (ADS)

    Alberti, Andrea; Robens, Carsten; Alt, Wolfgang; Brakhane, Stefan; Karski, Michał; Reimann, René; Widera, Artur; Meschede, Dieter

    2016-05-01

    We report on image processing techniques and experimental procedures to determine the lattice-site positions of single atoms in an optical lattice with high reliability, even for limited acquisition time or optical resolution. Determining the positions of atoms beyond the diffraction limit relies on parametric deconvolution in close analogy to methods employed in super-resolution microscopy. We develop a deconvolution method that makes effective use of the prior knowledge of the optical transfer function, noise properties, and discreteness of the optical lattice. We show that accurate knowledge of the image formation process enables a dramatic improvement on the localization reliability. This allows us to demonstrate super-resolution of the atoms’ position in closely packed ensembles where the separation between particles cannot be directly optically resolved. Furthermore, we demonstrate experimental methods to precisely reconstruct the point spread function with sub-pixel resolution from fluorescence images of single atoms, and we give a mathematical foundation thereof. We also discuss discretized image sampling in pixel detectors and provide a quantitative model of noise sources in electron multiplying CCD cameras. The techniques developed here are not only beneficial to neutral atom experiments, but could also be employed to improve the localization precision of trapped ions for ultra precise force sensing.

  10. Cooling by corralling: a route to antiferromagnetism in optical lattices

    NASA Astrophysics Data System (ADS)

    Loh, Yen Lee

    2012-02-01

    Cold atoms in optical lattices have emerged as a promising tool for emulating condensed matter Hamiltonians. Current experiments have observed ``Mott insulating'' behavior in the Fermi-Hubbard model at an average entropy S/N 1 kB/atom. Our quantum Monte Carlo simulations [1], in agreement with other methods, show that S/N 0.65 kB/atom is low enough to produce antiferromagnetism (AF) at the center of a harmonic trap. However, further progress in the field requires even lower entropies that are beyond the reach of traditional cooling techniques. I have proposed a way to attain very low temperatures and entropies (S/N < 0.03 kB/atom) by trapping fermions in a corral formed from another species of atoms [2]. This Fermi system can then be evolved into an antiferromagnet by morphing the lattice into a set of double wells, quasi-adiabatically. Quantum dynamics simulations have, so far, given promising results.[4pt] [1] Thereza Paiva, Yen Lee Loh, Mohit Randeria, Richard T. Scalettar, and Nandini Trivedi, ``Fermions in 3D optical lattices: Cooling protocol to obtain antiferromagnetism,'' PRL 107, 086401 (2011).[0pt] [2] Yen Lee Loh, ``Proposal for achieving very low entropies in optical lattice systems,'' arxiv:1108.0628.

  11. Optical-lattice Hamiltonians for relativistic quantum electrodynamics

    SciTech Connect

    Kapit, Eliot; Mueller, Erich

    2011-03-15

    We show how interpenetrating optical lattices containing Bose-Fermi mixtures can be constructed to emulate the thermodynamics of quantum electrodynamics (QED). We present models of neutral atoms on lattices in 1+1, 2+1, and 3+1 dimensions whose low-energy effective action reduces to that of photons coupled to Dirac fermions of the corresponding dimensionality. We give special attention to (2+1)-dimensional quantum electrodynamics (QED3) and discuss how two of its most interesting features, chiral symmetry breaking and Chern-Simons physics, could be observed experimentally.

  12. Effective Dirac dynamics of ultracold atoms in bichromatic optical lattices

    SciTech Connect

    Witthaut, D.; Salger, T.; Kling, S.; Grossert, C.; Weitz, M.

    2011-09-15

    We study the dynamics of ultracold atoms in tailored bichromatic optical lattices. By tuning the lattice parameters, one can readily engineer the band structure and realize a Dirac point, i.e., a true crossing of two Bloch bands. The dynamics in the vicinity of such a crossing is described by the one-dimensional Dirac equation, which is rigorously shown beyond the tight-binding approximation. Within this framework we analyze the effects of an external potential and demonstrate numerically that it is possible to demonstrate Klein tunneling with current experimental setups.

  13. Optical-lattice Hamiltonians for relativistic quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Kapit, Eliot; Mueller, Erich

    2011-03-01

    We show how interpenetrating optical lattices containing Bose-Fermi mixtures can be constructed to emulate the thermodynamics of quantum electrodynamics (QED). We present models of neutral atoms on lattices in 1+1, 2+1, and 3+1 dimensions whose low-energy effective action reduces to that of photons coupled to Dirac fermions of the corresponding dimensionality. We give special attention to (2+1)-dimensional quantum electrodynamics (QED3) and discuss how two of its most interesting features, chiral symmetry breaking and Chern-Simons physics, could be observed experimentally.

  14. Experimentally observed field–gas interaction in intense optical lattices

    SciTech Connect

    Graul, Jacob S.; Cornella, Barry M.; Ketsdever, Andrew D.; Lilly, Taylor C.; Shneider, Mikhail N.

    2013-12-09

    When a gas perturbed by a laser interference pattern, an optical lattice, exhibits a periodic modulation of its refractive index, strong Bragg diffraction of the perturbing light can occur. This scattering reduces the field's ability to further manipulate the gas. Experimental observations of Bragg scattering, evidence of a two-way coupling, are compared to the evolution of the light fields calculated by solutions to the wave equation. Comparison indicates momentum deposition as a prime contributor to the shape of the scattering function vs. lattice velocity, a rationale further supported through additional direct simulation Monte Carlo simulation.

  15. Proposed realization of itinerant ferromagnetism in optical lattices

    SciTech Connect

    Zhang Shizhong; Hung Hsianghsuan; Wu Congjun

    2010-11-15

    We propose a scheme to realize the itinerant ferromagnetism of two-component cold fermionic atoms in the p-orbital bands in optical lattices. The band flatness in the two-dimensional honeycomb lattice dramatically amplifies the interaction effect, driving the ferromagnetic transition even with a relatively weak repulsive interaction. This scheme has the advantage that the stability of the system can be maintained without causing decay to the molecular state as one approaches the Feshbach resonance from the side with the positive scattering length. Experimental signatures and detections are also discussed.

  16. Dynamics of matter solitons in weakly modulated optical lattices

    SciTech Connect

    Brazhnyi, V.A.; Konotop, V.V.; Kuzmiak, V.

    2004-10-01

    It is shown that matter solitons can be effectively managed by means of smooth variations of parameters of optical lattices in which the condensate is loaded. The phenomenon is based on the effect of lattice modulations on the carrier wave transporting the soliton and that is why it is well understood in terms of the effective mass approach, where a particular spatial configuration of the band structure is of primary importance. Linear, parabolic, and spatially localized modulations are considered as case examples. It is shown that these defects can originate an accelerating and oscillating motion of matter solitons as well as they can simulate soliton interactions with attractive and repulsive defects.

  17. Strongly Interacting Atom Lasers in Three-Dimensional Optical Lattices

    SciTech Connect

    Hen, Itay; Rigol, Marcos

    2010-10-29

    We show that the dynamical melting of a Mott insulator in a three-dimensional lattice leads to condensation at nonzero momenta, a phenomenon that can be used to generate strongly interacting atom lasers in optical lattices. For infinite on-site repulsion, the case considered here, the momenta at which bosons condense are determined analytically and found to have a simple dependence on the hopping amplitudes. The occupation of the condensates is shown to scale linearly with the total number of atoms in the initial Mott insulator. Our results are obtained by using a Gutzwiller-type mean-field approach, gauged against exact-diagonalization solutions of small systems.

  18. Prospects for Optical Clocks with a Blue-Detuned Lattice

    SciTech Connect

    Takamoto, M.; Katori, H.; Marmo, S. I.; Ovsiannikov, V. D.; Pal'chikov, V. G.

    2009-02-13

    We investigated the properties of optical lattice clocks operated with a repulsive light-shift potential. The magic wavelength, where light-shift perturbation for the clock transition cancels, was experimentally determined to be 389.889(9) nm for {sup 87}Sr. The hyperpolarizability effects on the clock transition were investigated theoretically. With minimal trapping field perturbation provided by the blue-detuned lattice, the fractional uncertainty due to the hyperpolarizability effects was found to be 2x10{sup -19} in the relevant clock transition.

  19. Mixtures of Strongly Interacting Bosons in Optical Lattices

    SciTech Connect

    Buonsante, P.; Penna, V.; Giampaolo, S. M.; Illuminati, F.; Vezzani, A.

    2008-06-20

    We investigate the properties of strongly interacting heteronuclear boson-boson mixtures loaded in realistic optical lattices, with particular emphasis on the physics of interfaces. In particular, we numerically reproduce the recent experimental observation that the addition of a small fraction of {sup 41}K induces a significant loss of coherence in {sup 87}Rb, providing a simple explanation. We then investigate the robustness against the inhomogeneity typical of realistic experimental realizations of the glassy quantum emulsions recently predicted to occur in strongly interacting boson-boson mixtures on ideal homogeneous lattices.

  20. Exploring spin-orbit coupling in a non-degenerate optical lattice clock

    NASA Astrophysics Data System (ADS)

    Wall, Michael L.; Koller, Andrew P.; Li, Shuming; Rey, Ana Maria

    2015-05-01

    Optical lattice clocks have progressed in recent years to become not only precise timekeepers, but also sensitive probes of many-body physics. We consider a 1D optical lattice clock in which the wavelength of the laser that interrogates the clock transition is comparable to the optical lattice spacing. This light-matter coupling imprints a spatially dependent phase on the atomic internal state superposition, and this phase can be interpreted as a spin-orbit coupling. We show that this spin-orbit coupling manifests itself in Ramsey spectroscopy as an s-wave density shift in otherwise identically prepared fermions, even at temperatures significantly larger than the tunneling. Further, we show that Rabi spectroscopy can be mapped to a Hofstadter model on a two-leg ladder with chiral eigenstates. Using a modified Rabi procedure, we show how to extract momentum-resolved signatures of chirality solely by spectroscopic means. The effects of finite temperature, gaussian transverse confinement, and non-separability between transverse and axial degrees of freedom are discussed. This work has been financially supported by JILA-NSF-PFC-1125844, NSF-PIF-1211914, ARO, AFOSR, AFOSR-MURI, NDSEG, and NRC.

  1. Measuring time-dependent Greens Functions of strongly correlated gases in optical lattices

    NASA Astrophysics Data System (ADS)

    Kantian, Adrian; Schollwöck, Ulrich; Giamarchi, Thierry

    2015-03-01

    Recent advances in single-site addressing in optical-lattice confined strongly correlated ultracold gases promise to deliver entirely new capabilities for these systems to serve as quantum simulators. We show how these advances may be employed to design in-situ measurements of both local and nonlocal time-dependent Greens functions as well as higher-order correlators. Using analytics side-by-side with time-dependent DMRG we quantify the practically available resolutions of these schemes - which can be applied for practically any 1D and 2D system of lattice-confined ultracold atoms - for several examples of interest, such as the mobile impurity problem and the superfluid-Mott insulator transition. This work was supported in part by the Swiss NSF under Division II.

  2. Design and Finite Temperature Aspects of Atoms in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Blakie, Peter

    2003-05-01

    The control and manipulation of Bose-Einstein condensates with optical lattices is a major current interest in cold atom research, and is an important component in proposals for quantum computing with neutral atoms. A condensate loaded into an optical lattice can be described by a Bose-Hubbard Hamiltonian and presents a unique opportunity for investigating aspects of many-body physics in a controlled manner, as typified by a recent experimental investigation where the quantum phase transition of atoms from a superfluid to Mott-insulating state was observed [1]. In this talk we consider the interference of three co-planar equal frequency light fields, which are far detuned from atomic resonance. Atoms within the region of the light field overlap will experience a periodic light shift potential that forms a two-dimensional optical lattice. We demonstrate the range of possible geometries for this type of lattice, obtainable by varying the propagation directions of the light fields. From band structure calculations we show how the tunneling rates can be manipulated to control the effective number of nearest neighbors. We discuss possible applications of this work to cold atom research. In the second part of this talk we consider recent experiments done in collaboration with Morsch et al. [2] investigating the non-adiabatic loading of a condensate into an optical lattice. We discuss the dephasing mechanisms and preliminary results in developing a model for the long time dynamically behavior. [1] M. Greiner, O. Mandel, T.Esslinger, T.W. Hansch and I. Bloch, Nature 415, 2002. [2] O. Morsch, J.H. Müller, D. Ciampini, M. Cristiani, P.B. Blakie, C.J. Williams, P.S. Julienne and E. Arimondo. Cond-mat/0208162 (to appear in Phys. Rev. A)

  3. Single ions trapped in a one-dimensional optical lattice.

    PubMed

    Enderlein, Martin; Huber, Thomas; Schneider, Christian; Schaetz, Tobias

    2012-12-07

    We report on three-dimensional optical trapping of single ions in a one-dimensional optical lattice formed by two counterpropagating laser beams. We characterize the trapping parameters of the standing-wave using the ion as a sensor stored in a hybrid trap consisting of a radio-frequency (rf), a dc, and the optical potential. When loading ions directly from the rf into the standing-wave trap, we observe a dominant heating rate. Monte Carlo simulations confirm rf-induced parametric excitations within the deep optical lattice as the main source. We demonstrate a way around this effect by an alternative transfer protocol which involves an intermediate step of optical confinement in a single-beam trap avoiding the temporal overlap of the standing-wave and the rf field. Implications arise for hybrid (rf-optical) and pure optical traps as platforms for ultracold chemistry experiments exploring atom-ion collisions or quantum simulation experiments with ions, or combinations of ions and atoms.

  4. Cold bosons in optical lattices: a tutorial for exact diagonalization

    NASA Astrophysics Data System (ADS)

    Raventós, David; Graß, Tobias; Lewenstein, Maciej; Juliá-Díaz, Bruno

    2017-06-01

    Exact diagonalization (ED) techniques are a powerful method for studying many-body problems. Here, we apply this method to systems of few bosons in an optical lattice, and use it to demonstrate the emergence of interesting quantum phenomena such as fragmentation and coherence. Starting with a standard Bose-Hubbard Hamiltonian, we first revise the characterisation of the superfluid to Mott insulator (MI) transitions. We then consider an inhomogeneous lattice, where one potential minimum is made much deeper than the others. The MI phase due to repulsive on-site interactions then competes with the trapping of all atoms in the deep potential. Finally, we turn our attention to attractively interacting systems, and discuss the appearance of strongly correlated phases and the onset of localisation for a slightly biased lattice. The article is intended to serve as a tutorial for ED of Bose-Hubbard models.

  5. Pinning an ion with an intracavity optical lattice.

    PubMed

    Linnet, Rasmus B; Leroux, Ian D; Marciante, Mathieu; Dantan, Aurélien; Drewsen, Michael

    2012-12-07

    We report one-dimensional pinning of a single ion by an optical lattice. A standing-wave cavity produces the lattice potential along the rf-field-free axis of a linear Paul trap. The ion's localization is detected by measuring its fluorescence when excited by standing-wave fields with the same period, but different spatial phases. The experiments agree with an analytical model of the localization process, which we test against numerical simulations. For the best localization achieved, the ion's average coupling to the cavity field is enhanced from 50% to 81(3)% of its maximum possible value, and we infer that the ion is bound in a lattice well with over 97% probability.

  6. Dynamical phase interferometry of cold atoms in optical lattices

    SciTech Connect

    London, Uri; Gat, Omri

    2011-12-15

    We study the propagation of cold-atom wave packets in an interferometer with a Mach-Zehnder topology based on the dynamical phase of Bloch oscillation in a weakly forced optical lattice with a narrow potential barrier that functions as a cold-atom wave-packet splitter. We calculate analytically the atomic wave function, and show that the expected number of atoms in the two outputs of the interferometer oscillates rapidly as a function of the angle between the potential barrier and the forcing direction with period proportional to the external potential difference across a lattice spacing divided by the lattice band energy scale. The interferometer can be used as a high-precision force probe whose principle of operation is different from current interferometers based on the overall position of Bloch oscillating wave packets.

  7. Measuring spin correlations in optical lattices using superlattice potentials

    SciTech Connect

    Pedersen, K. G. L.; Andersen, B. M.; Soerensen, A. S.; Bruun, G. M.; Syljuaasen, O. F.

    2011-10-15

    We suggest two experimental methods for probing both short- and long-range spin correlations of atoms in optical lattices using superlattice potentials. The first method involves an adiabatic doubling of the periodicity of the underlying lattice to probe neighboring singlet (triplet) correlations for fermions (bosons) by the occupation of the resulting vibrational ground state. The second method utilizes a time-dependent superlattice potential to generate spin-dependent transport by any number of prescribed lattice sites, and probes correlations by the resulting number of doubly occupied sites. For experimentally relevant parameters, we demonstrate how both methods yield large signatures of antiferromagnetic correlations of strongly repulsive fermionic atoms in a single shot of the experiment. Lastly, we show how this method may also be applied to probe d-wave pairing, a possible ground-state candidate for the doped repulsive Hubbard model.

  8. Microscopic Studies of Quantum Phase Transitions in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Bakr, Waseem S.

    2011-12-01

    In this thesis, I report on experiments that microscopically probe quantum phase transitions of ultracold atoms in optical lattices. We have developed a "quantum gas microscope" that allowed, for the first time, optical imaging and manipulation of single atoms in a quantum-degenerate gas on individual sites of an optical lattice. This system acts as a quantum simulator of strongly correlated materials, which are currently the subject of intense research because of the technological potential of high--T c superconductors and spintronic materials. We have used our microscope to study the superfluid to Mott insulator transition in bosons and a magnetic quantum phase transition in a spin system. In our microscopic study of the superfluid-insulator transition, we have characterized the on-site number statistics in a space- and time-resolved manner. We observed Mott insulators with fidelities as high as 99%, corresponding to entropies of 0.06kB per particle. We also measured local quantum dynamics and directly imaged the shell structure of the Mott insulator. I report on the first quantum magnetism experiments in optical lattices. We have realized a quantum Ising chain in a magnetic field, and observed a quantum phase transition between a paramagnet and antiferromagnet. We achieved strong spin interactions by encoding spins in excitations of a Mott insulator in a tilted lattice. We detected the transition by measuring the total magnetization of the system across the transition using in-situ measurements as well as the Neel ordering in the antiferromagnetic state using noise-correlation techniques. We characterized the dynamics of domain formation in the system. The spin mapping introduced opens up a new path to realizing more exotic states in optical lattices including spin liquids and quantum valence bond solids. As our system sizes become larger, simulating their physics on classical computers will require exponentially larger resources because of entanglement build

  9. Sorting via injection of particle streams into an optical lattice

    NASA Astrophysics Data System (ADS)

    MacDonald, Michael P.; Neale, Steven L.; Smith, Ryan L.; Spalding, Gabriel C.; Dholakia, Kishan

    2005-08-01

    The growth of research into microfluidics, especially towards micro-Total Analysis Systems (μTAS), is leading to a demand for highly efficient and accurate methods for analyte delivery, sorting, mixing and analysis. Optical techniques, due to their non-invasive, non-contact properties are ideally suited to integration in to microfluidic systems. One of the key abilities in a μTAS device is the ability to sort microscopic matter. When done optically this typically involves fluorescence detection, management of the information detected and subsequent action such as the actuation of an electric field or electro-mechanical valve. We present here a method whereby the detection of a micro-particle's properties is done passively, with simultaneous separation of those particles. To do this particle streams are injected into a three-dimensional crystal-like lattice of optical intensity maxima. A particle's response to the three-dimensional optical potential landscape formed by the lattice depends on its polarisability. This leads to a sensitivity to size, refractive index and shape. More strongly interacting particles are deflected away from the main flow whilst those that interact weakly are washed straight through the lattice without little or no net deflection. We present analysis of both injection and subsequent re-routing/sorting of particle streams, using body-centred tetragonal and three-dimensional "log-pile" optical lattices to separate both inert colloid and blood cells by refractive index or size. Sorting with an efficiency as high as 96% has been achieved with particle deflections in excess of 45 degrees.

  10. Wannier functions using a discrete variable representation for optical lattices

    NASA Astrophysics Data System (ADS)

    Paul, Saurabh; Tiesinga, Eite

    2016-09-01

    We propose a numerical method using the discrete variable representation (DVR) for constructing real-valued Wannier functions localized in a unit cell for both symmetric and asymmetric periodic potentials. We apply these results to finding Wannier functions for ultracold atoms trapped in laser-generated optical lattices. Following S. Kivelson [Phys. Rev. B 26, 4269 (1982), 10.1103/PhysRevB.26.4269], for a symmetric lattice with inversion symmetry, we construct Wannier functions as eigenstates of the position operators x ̂, y ̂, and z ̂ restricted to single-particle Bloch functions belonging to one or more bands. To ensure that the Wannier functions are real-valued, we numerically obtain the band structure and real-valued eigenstates using a uniform Fourier grid DVR. We then show, by a comparison of tunneling energies, that the Wannier functions are accurate for both inversion-symmetric and asymmetric potentials to better than 10 significant digits when using double-precision arithmetic. The calculations are performed for an optical lattice with double-wells per unit cell with tunable asymmetry along the x axis and a single sinusoidal potential along the perpendicular directions. Localized functions at the two potential minima within each unit cell are similarly constructed, but using a superposition of single-particle solutions from the two lowest bands. We finally use these localized basis functions to determine the two-body interaction energies in the Bose-Hubbard model and show the dependence of these energies on lattice asymmetry.

  11. Ytterbium optical lattice clock with 10-18 level characterization

    NASA Astrophysics Data System (ADS)

    Phillips, Nathaniel; Sherman, Jeff; Beloy, Kyle; Hinkley, Nathan; Schioppo, Marco; Oates, Chris; Ludlow, Andrew

    2014-05-01

    A recent comparison of two ytterbium-based optical lattice clocks at NIST demonstrated record stability of 1 . 6 parts in 1018 after 25,000s averaging. We report on measurements of the two primary systematic effects that shift the ultra-narrow clock transition, towards a reduction of the clock uncertainty to the 10-18 level. Uncertainty stemming from the blackbody radiation (BBR) shift is largely due to imprecise knowledge of the thermal environment surrounding the atoms. We detail the construction and operation of an in-vacuum, thermally-regulated radiation shield, which permits laser cooling and trapping while enabling an absolute temperature measurement with < 20 mK precision. Additionally, while operation of the optical lattice at the magic wavelength (λm) cancels the scalar Stark shift (since both clock states shift equally), higher-order vector and two-photon hyperpolarizability shifts remain. To evaluate these effects, as well as the polarizability away from λm, we implement a lattice buildup cavity around the atoms. The resulting twenty-fold enhancement of the lattice intensity provides a significant lever arm for precise measurement of these effects.

  12. Nonlinear optical higher-order effects in an optical lattice clock

    NASA Astrophysics Data System (ADS)

    Ovsyannikov, V. D.; Marmo, S. I.; Mokhnenko, S. N.; Pal'chikov, V. G.

    2017-06-01

    The development of optical frequency standards with a relative uncertainty of reproducing the time and frequency units at a level as low as 10-17-10-18 calls for an unprecedented accuracy in estimating the role of higher orders of optical nonlinearity, caused by the influence of the optical lattice on the frequency shift of the ‘clock transition’. This paper presents a systematic calculation of the contributions of multipole nonlinear anharmonic effects to the error of clocks based on optical lattices for alkaline-earth-like Sr, Yb, and Hg atoms.

  13. Superlubric-pinned Aubry transition of two dimensional monolayers in optical lattices

    NASA Astrophysics Data System (ADS)

    Mandelli, Davide; Vanossi, Andrea; Manini, Nicola; Tosatti, Erio

    Two-dimensional (2D) crystalline colloidal monolayers sliding over a laser-induced optical lattice ``corrugation'' potential emulate friction between ideal crystal surfaces. Static friction is always present when the monolayer and the optical lattices are commensurate, but when they are incommensurate the presence or absence of static friction depends upon the system parameters. In 1D, at the Aubry dynamical phase transition the static friction goes continuously from zero (superlubricity) to finite as the periodic corrugation strength is increased. We look for the Aubry-like transition in the more realistic 2D case of a monolayer in an incommensurate periodic potential using molecular dynamics simulations. Results confirm a clear and sharp 2D superlubric-pinned transition upon increasing corrugation strength. Unlike the 1D Aubry transition which is continuous, the 2D transition is first-order, with a jump of static friction. At the 2D Aubry transition there is no change of symmetry, a sudden rise of the colloid-colloid interaction energy, and a compensating drop of the colloid-corrugation energy. The observability of the superlubric-pinned colloid transition is proposed and discussed. This work has been supported by ERC Advanced Grant N. 320796 MODPHYSFRICT.

  14. Quantum phase transitions in optical lattices beyond the Bogoliubov approximation

    NASA Astrophysics Data System (ADS)

    Kleinert, H.; Narzikulov, Z.; Rakhimov, Abdulla

    2012-06-01

    We study the quantum phase transition from a superfluid to a Mott insulator in optical lattices using a Bose-Hubbard Hamiltonian. For this purpose we develop a field theoretical approach in terms of path integral formalism to calculate the second-order quantum corrections to the energy density as well as to the superfluid fraction in cubic optical lattices. Using the present approach, the condensate fraction and ground-state energy are calculated as functions of the s-wave scattering length. In contrast to the Bogoliubov model, which is, technically speaking, a one-loop approximation, we carry the calculation up to two loops and improve the result further by variational perturbation theory. The result suggests that the quantum phase transition exists.

  15. Quantum phases of Fermi-Fermi mixtures in optical lattices

    NASA Astrophysics Data System (ADS)

    Iskin, M.; Sá de Melo, C. A. R.

    2008-07-01

    The ground-state phase diagram of Fermi-Fermi mixtures in optical lattices is analyzed as a function of interaction strength, population imbalance, filling fraction, and tunneling parameters. It is shown that population imbalanced Fermi-Fermi mixtures reduce to strongly interacting Bose-Fermi mixtures in the molecular limit, in sharp contrast to homogeneous or harmonically trapped systems, where the resulting Bose-Fermi mixture is weakly interacting. Furthermore, insulating phases are found in optical lattices of Fermi-Fermi mixtures in addition to the standard phase-separated or coexisting superfluid-excess-fermion phases found in homogeneous systems. The insulating states can be a molecular Bose-Mott insulator (BMI), a Fermi-Pauli insulator (FPI), a phase-separated BMI-FPI mixture, or a Bose-Fermi checkerboard.

  16. Novel Superfluidity of Trapped Fermi Atoms Loaded on Optical Lattices

    NASA Astrophysics Data System (ADS)

    Machida, Masahiko; Yamada, Susumu

    2005-03-01

    We investigate a possibility of superfluidity in a trapped gas of Fermi atoms with a repulsive interaction in the presence of an optical lattice. Applying the exact diagonalization method to a one-dimensional Hubbard model including the trap potential, we find that, when the strength of the repulsive interaction exceeds a critical value, the binding energy of two Fermi atoms becomes negative below the half-filling case, indicating that an attractive interaction effectively works between Fermi atoms. In this case, a "Mott insulating core" appears in the center of the trap, where each site is occupied by one atom. The Cooper-pair correlation strongly develops between atoms in the left and right hand sides of this core. Furthermore, we show a ground-state phase diagram including the superfluidity on the trapped Fermi atoms loaded on optical lattices.

  17. Superfluid and insulating phases of fermion mixtures in optical lattices.

    PubMed

    Iskin, M; Sá de Melo, C A R

    2007-08-24

    The ground state phase diagram of fermion mixtures in optical lattices is analyzed as a function of interaction strength, fermion filling factor, and tunneling parameters. In addition to standard superfluid, phase-separated or coexisting superfluid -- excess-fermion phases found in homogeneous or harmonically trapped systems, fermions in optical lattices have several insulating phases, including a molecular Bose-Mott insulator (BMI), a Fermi-Pauli (band) insulator (FPI), a phase-separated BMI-FPI mixture or a Bose-Fermi checkerboard (BFC). The molecular BMI phase is the fermion mixture counterpart of the atomic BMI found in atomic Bose systems, the BFC or BMI-FPI phases exist in Bose-Fermi mixtures, and lastly the FPI phase is particular to the Fermi nature of the constituent atoms of the mixture.

  18. Damped Bloch oscillations of cold atoms in optical lattices

    SciTech Connect

    Kolovsky, A.R.; Ponomarev, A.V.; Korsch, H.J.

    2002-11-01

    The paper studies Bloch oscillations of cold neutral atoms in the optical lattice. The effect of spontaneous emission on the dynamics of the system is analyzed both analytically and numerically. The spontaneous emission is shown to cause (i) the decay of Bloch oscillations with the decrement given by the rate of spontaneous emission and (ii) the diffusive spreading of the atoms with a diffusion coefficient depending on both the rate of spontaneous emission and the Bloch frequency.

  19. Driven optical lattices as strong-field simulators

    SciTech Connect

    Arlinghaus, Stephan; Holthaus, Martin

    2010-06-15

    We argue that ultracold atoms in strongly shaken optical lattices can be subjected to conditions similar to those experienced by electrons in laser-irradiated crystalline solids, but without introducing secondary polarization effects. As a consequence, one can induce nonperturbative multiphoton-like resonances due to the mutual penetration of ac-Stark-shifted Bloch bands. These phenomena can be detected with a combination of currently available laboratory techniques.

  20. Ab Initio Study of Ultracold Polar Molecules in Optical Lattices

    DTIC Science & Technology

    2010-01-01

    polar molecules by using optical lattices and microwave fields’’, US-Japan Joint Seminar on Coherent Quantum Systems, Breckenridge, USA, August (2006...corresponds to the dissociation energy of both 40K and 87Rb in the energetically lowest hyperfine state . The levels are grouped by the projection quantum ...vibrational state . The J = 1 to J = 2 transition occurs at a larger photon frequency. For the near-resonance frequencies the polarizabilities in Fig

  1. Observation of discrete diffraction patterns in an optically induced lattice.

    PubMed

    Sheng, Jiteng; Wang, Jing; Miri, Mohammad-Ali; Christodoulides, Demetrios N; Xiao, Min

    2015-07-27

    We have experimentally observed the discrete diffraction of light in a coherently prepared multi-level atomic medium. This is achieved by launching a probe beam into an optical lattice induced from the interference of two coupling beams. The diffraction pattern can be controlled through the atomic parameters such as two-photon detuning and temperature, as well as orientations of the coupling and probe beams. Clear diffraction patterns occur only near the two-photon resonance.

  2. Spin-orbit-coupled fermions in an optical lattice clock

    NASA Astrophysics Data System (ADS)

    Kolkowitz, S.; Bromley, S. L.; Bothwell, T.; Wall, M. L.; Marti, G. E.; Koller, A. P.; Zhang, X.; Rey, A. M.; Ye, J.

    2017-02-01

    Engineered spin-orbit coupling (SOC) in cold-atom systems can enable the study of new synthetic materials and complex condensed matter phenomena. However, spontaneous emission in alkali-atom spin-orbit-coupled systems is hindered by heating, limiting the observation of many-body effects and motivating research into potential alternatives. Here we demonstrate that spin-orbit-coupled fermions can be engineered to occur naturally in a one-dimensional optical lattice clock. In contrast to previous SOC experiments, here the SOC is both generated and probed using a direct ultra-narrow optical clock transition between two electronic orbital states in 87Sr atoms. We use clock spectroscopy to prepare lattice band populations, internal electronic states and quasi-momenta, and to produce spin-orbit-coupled dynamics. The exceptionally long lifetime of the excited clock state (160 seconds) eliminates decoherence and atom loss from spontaneous emission at all relevant experimental timescales, allowing subsequent momentum- and spin-resolved in situ probing of the SOC band structure and eigenstates. We use these capabilities to study Bloch oscillations, spin-momentum locking and Van Hove singularities in the transition density of states. Our results lay the groundwork for using fermionic optical lattice clocks to probe new phases of matter.

  3. Spin–orbit-coupled fermions in an optical lattice clock

    NASA Astrophysics Data System (ADS)

    Kolkowitz, S.; Bromley, S. L.; Bothwell, T.; Wall, M. L.; Marti, G. E.; Koller, A. P.; Zhang, X.; Rey, A. M.; Ye, J.

    2016-12-01

    Engineered spin–orbit coupling (SOC) in cold-atom systems can enable the study of new synthetic materials and complex condensed matter phenomena. However, spontaneous emission in alkali-atom spin–orbit-coupled systems is hindered by heating, limiting the observation of many-body effects and motivating research into potential alternatives. Here we demonstrate that spin–orbit-coupled fermions can be engineered to occur naturally in a one-dimensional optical lattice clock. In contrast to previous SOC experiments, here the SOC is both generated and probed using a direct ultra-narrow optical clock transition between two electronic orbital states in 87Sr atoms. We use clock spectroscopy to prepare lattice band populations, internal electronic states and quasi-momenta, and to produce spin–orbit-coupled dynamics. The exceptionally long lifetime of the excited clock state (160 seconds) eliminates decoherence and atom loss from spontaneous emission at all relevant experimental timescales, allowing subsequent momentum- and spin-resolved in situ probing of the SOC band structure and eigenstates. We use these capabilities to study Bloch oscillations, spin–momentum locking and Van Hove singularities in the transition density of states. Our results lay the groundwork for using fermionic optical lattice clocks to probe new phases of matter.

  4. Detecting atoms trapped in an optical lattice using a tapered optical nanofiber.

    PubMed

    Hennessy, T; Busch, Th

    2014-12-29

    Optical detection of structures with dimensions smaller than an optical wavelength requires devices that work on scales beyond the diffraction limit. Here we present the possibility of using a tapered optical nanofiber as a detector to resolve individual atoms trapped in an optical lattice in the Mott insulator phase. We show that the small size of the fiber combined with an enhanced photon collection rate can allow for the attainment of large and reliable measurement signals.

  5. Nonlocal optical properties in periodic lattice of graphene layers.

    PubMed

    Chern, Ruey-Lin; Han, Dezhuan

    2014-02-24

    Based on the effective medium model, nonlocal optical properties in periodic lattice of graphene layers with the period much less than the wavelength are investigated. Strong nonlocal effects are found in a broad frequency range for TM polarization, where the effective permittivity tensor exhibits the Lorentzian resonance. The resonance frequency varies with the wave vector and coincides well with the polaritonic mode. Nonlocal features are manifest on the emergence of additional wave and the occurrence of negative refraction. By examining the characters of the eigenmode, the nonlocal optical properties are attributed to the excitation of plasmons on the graphene surfaces.

  6. Cold Atomic Gases in Optical Lattices with Disorder

    NASA Astrophysics Data System (ADS)

    Schulte, T.; Drenkelforth, S.; Kruse, J.; Ertmer, W.; Arlt, J. J.; Kantian, A.; Santos, L. Sanchez-Palencia L.; Sanpera, A.; Sacha, K.; Zoller, P.; Lewenstein, M.; Zakrzewski, J.

    2007-01-01

    Cold atomic gases placed in optical lattices enable studies of simple condensed matter theory models with parameters that may be tuned relatively easily. When the optical potential is randomized (e.g. using laser speckle to create a random intensity distribution) one may be able to observe Anderson localization of matter waves for non-interacting bosons, the so-called Bose glass in the presence of interactions, as well as the Fermi glass or quantum spin glass for mixtures of fermions and bosons.

  7. Label-free optical detection of bacteria on a 1-D photonic crystal of porous silicon

    NASA Astrophysics Data System (ADS)

    Wu, Chia-Chen; Alvarez, Sara D.; Rang, Camilla U.; Chao, Lin; Sailor, Michael J.

    2009-02-01

    The construction of a specific, label-free, bacteria biosensor using porous silicon 1-D photonic crystals will be described. Bacteria resident on the surface of porous silicon act as scattering centers for light resonant with the photonic crystal; the diffusely scattered light possesses the optical spectrum of the underlying photonic crystal. Using a spectrometer fitted to a light microscope, the bacteria are imaged without using exogenous dyes or labels and are quantified by measuring the intensity of scattered light. In order to selectively bind and identify bacteria using porous Si, we use surface modifications to reduce nonspecific binding to the surface and to engineer bacteria specificity onto the surface. Bovine serum albumin (BSA) was adsorbed to the porous Si surface to reduce nonspecific binding of bacteria. The coatings were then chemically activated to immobilize polyclonal antibodies specific to Escherichia coli. Two E. coli strains were used in our study, E. coli DH5α and non-pathogenic enterohemorrhagic Escherichia coli (EHEC) strain. The nonpathogenic Vibrio cholerae O1 strain was used to test for antibody specificity. Successful attachment of antibodies was measured using fluorescence microscopy and the scattering method was used to test for bacteria binding specificity.

  8. Quasi-1D States Confined in a Self-Assembled Organic Super-Lattice of TTF-TCNQ on Ag(111)

    NASA Astrophysics Data System (ADS)

    Jeon, Seokmin; Ganesh, Panchapakesan; Sumpter, Bobby; Cerdá, Jorge Iribas; Maksymovych, Petro; CNMS Team; ICMM-CSIC Team

    2015-03-01

    Organic charge transfer complexes (CTC) have drawn much attention due to their potential applications to conducting or semiconducting organic thin films and contacts in devices. TTF-TCNQ is a historic organic CTC with one of the highest conductivity values among numerous organic conductors. As a two-component molecular material, TTF-TCNQ in a low-dimension form on a surface naturally creates monolayer super-lattices with corrugated electrostatic potential and adsorbate-induced strain. Generally this will lead to strong confinement of the surface states, although the detailed response of the surface electronic structure remains to be understood. We investigated TTF-TCNQ monolayer films grown on Ag(111), Au(111) and Ag(100) surfaces using STM/STS at 4.3 K. Confinement of sp-derived surface states was indeed ubiquitous, including spontaneous formation of quantum dots and quasi-1D bands. The small periodicity of the lattice caused a complete depopulation of the surface states, with up to 1 eV upshift of the band minimum - much stronger effect than normally observed in assemblies. This also allows us to infer the height of the confining potential using 1D Kronig-Penney model and critically assess the long-standing problem of molecule-surface charge transfer. A portion of this research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.

  9. Probing many-body interactions in an optical lattice clock

    SciTech Connect

    Rey, A.M.; Gorshkov, A.V.; Kraus, C.V.; Martin, M.J.; Bishof, M.; Swallows, M.D.; Zhang, X.; Benko, C.; Ye, J.; Lemke, N.D.; Ludlow, A.D.

    2014-01-15

    We present a unifying theoretical framework that describes recently observed many-body effects during the interrogation of an optical lattice clock operated with thousands of fermionic alkaline earth atoms. The framework is based on a many-body master equation that accounts for the interplay between elastic and inelastic p-wave and s-wave interactions, finite temperature effects and excitation inhomogeneity during the quantum dynamics of the interrogated atoms. Solutions of the master equation in different parameter regimes are presented and compared. It is shown that a general solution can be obtained by using the so called Truncated Wigner Approximation which is applied in our case in the context of an open quantum system. We use the developed framework to model the density shift and decay of the fringes observed during Ramsey spectroscopy in the JILA {sup 87}Sr and NIST {sup 171}Yb optical lattice clocks. The developed framework opens a suitable path for dealing with a variety of strongly-correlated and driven open-quantum spin systems. -- Highlights: •Derived a theoretical framework that describes many-body effects in a lattice clock. •Validated the analysis with recent experimental measurements. •Demonstrated the importance of beyond mean field corrections in the dynamics.

  10. Strongly interacting fermions in optical lattices and superlattices

    NASA Astrophysics Data System (ADS)

    Goodman, Timothy S.

    This dissertation summarizes my recent work regarding systems of strongly interacting fermionic atoms in optical lattices. This work addresses the combination of two experimental techniques that have been the subject of much recent research in ultracold atom physics. One is the use of optical lattices, which provide a means to realize diverse interaction configurations within a clean, controllable system. The other is the use of magnetically tunable Feshbach resonances to control the strength of the interatomic interaction. Together, these techniques offer the possibility of an experimental realization of many important model Hamiltonians of condensed matter physics, and may also lead to the discovery of new physics. Recent study of this system has shown that strong interactions near Feshbach resonance will lead to the population of multiple lattice bands, and that collisions between atoms on neighboring sites cannot be neglected. These effects lead to a complicated Hamiltonian, but one which can be simplified to an effective single-band model equivalent to the generalized Hubbard model (GHM), which is an extension of the Hubbard model that includes correlated hopping terms. My main results concern the study of this model. The strong correlations between the particles make it difficult to definitively determine the many body physics of the GHM. As a first approach to understanding the GHM in optical lattices, I focus mainly on cases where the problem is greatly simplified by allowing interactions among only small groups of lattice sites. This restriction can be implemented in experiments using an optical superlattice potential. Our results include a proposed scheme (based on double-well superlattices) to empirically verify that the GHM describes this system and to directly measure the various parameters of this model. Other results include exact solutions on four-site square plaquettes, which demonstrate that d-wave excitations can occur in the low-energy states

  11. Novel orbital physics with fermions in optical lattices

    NASA Astrophysics Data System (ADS)

    Wu, Congjun

    2009-03-01

    Orbitals, a degree of freedom characterized by orbital degeneracy and spatial anisotropy and independent of change and spin, play important roles in magnetism and superconductivity in transition metal oxides. In this talk, we will show that the rapid progress of cold atom physics has opened up an opportunity to study novel features of orbital physics, which do not appear usual solid state systems. In particular, the px;y-orbital system of the honeycomb lattice exhibits amazingly rich and fundamentally different behavior from that in the pz-orbital system of graphene. Its flat band structure dramatically amplifies interaction effects, providing a natural way to study non-perturbative strong correlation phenomena such as Wigner crystallization, and ferromagnetism which is an important field in condensed matter physics but has not attracted much attention in the cold atom community. Furthermore, in the Mott-insulating states, the orbital degree of freedom enables superexchange interactions as spin does. We will show how spatial anisotropy generates frustration in such systems, which leads to a promising way to the exciting orbital liquid states. At last, we will present that a topological insulating phase occurs in the presence of the lattice rotation, as an orbital analogy of the quantum anomalous Hall effect of electron systems. [3pt] References:[0pt] 1. Congjun Wu, ``Orbital analogue of quantum anomalous Hall effect in p-band systems,'' Phys. Rev. Lett. 101, 186807 (2008). [0pt] 2. Shizhong Zhang, Congjun Wu, ``Proposed realization of itinerant ferromagnetism in optical lattices,'' arXiv:0805.3031. [0pt] 3. Congjun Wu, ``Orbital orderings and frustrations of p-band systems in optical lattices,'' Phys. Rev. Lett. 100, 200406 (2008).[0pt] 4. Congjun Wu , and S. Das Sarma, ``The px,y-orbital counterpart of graphene: cold atoms in the honeycomb optical lattice,'' Phys. Rev. B 77, 235107 (2008).[0pt] 5. Congjun Wu, Doron Bergman, Leon Balents, and S. Das Sarma, ``Flat

  12. Criterion for Bosonic Superfluidity in an Optical Lattice

    SciTech Connect

    Diener, Roberto B.; Zhou Qi; Zhai Hui; Ho, T.-L.

    2007-05-04

    We show that the current method of determining superfluidity in optical lattices based on a visibly sharp bosonic momentum distribution n(k) can be misleading, for even a normal Bose gas can have a similarly sharp n(k). We show that superfluidity in a homogeneous system can be detected from the so-called visibility (v) of n(k)--that v must be 1 within O(N{sup -2/3}), where N is the number of bosons. We also show that the T=0 visibility of trapped lattice bosons is far higher than what is obtained in some current experiments, suggesting strong temperature effects and that these states can be normal. These normal states allow one to explore the physics in the quantum critical region.

  13. Quantum simulation of frustrated classical magnetism in triangular optical lattices.

    PubMed

    Struck, J; Ölschläger, C; Le Targat, R; Soltan-Panahi, P; Eckardt, A; Lewenstein, M; Windpassinger, P; Sengstock, K

    2011-08-19

    Magnetism plays a key role in modern technology and stimulates research in several branches of condensed matter physics. Although the theory of classical magnetism is well developed, the demonstration of a widely tunable experimental system has remained an elusive goal. Here, we present the realization of a large-scale simulator for classical magnetism on a triangular lattice by exploiting the particular properties of a quantum system. We use the motional degrees of freedom of atoms trapped in an optical lattice to simulate a large variety of magnetic phases: ferromagnetic, antiferromagnetic, and even frustrated spin configurations. A rich phase diagram is revealed with different types of phase transitions. Our results provide a route to study highly debated phases like spin-liquids as well as the dynamics of quantum phase transitions.

  14. Synthetic Spin-Orbit Coupling in an Optical Lattice Clock

    NASA Astrophysics Data System (ADS)

    Wall, Michael L.; Koller, Andrew P.; Li, Shuming; Zhang, Xibo; Cooper, Nigel R.; Ye, Jun; Rey, Ana Maria

    2016-01-01

    We propose the use of optical lattice clocks operated with fermionic alkaline-earth atoms to study spin-orbit coupling (SOC) in interacting many-body systems. The SOC emerges naturally during the clock interrogation, when atoms are allowed to tunnel and accumulate a phase set by the ratio of the "magic" lattice wavelength to the clock transition wavelength. We demonstrate how standard protocols such as Rabi and Ramsey spectroscopy that take advantage of the sub-Hertz resolution of state-of-the-art clock lasers can perform momentum-resolved band tomography and determine SOC-induced s -wave collisions in nuclear-spin-polarized fermions. With the use of a second counterpropagating clock beam, we propose a method for engineering controlled atomic transport and study how it is modified by p - and s -wave interactions. The proposed spectroscopic probes provide clean and well-resolved signatures at current clock operating temperatures.

  15. Synthetic Spin-Orbit Coupling in an Optical Lattice Clock.

    PubMed

    Wall, Michael L; Koller, Andrew P; Li, Shuming; Zhang, Xibo; Cooper, Nigel R; Ye, Jun; Rey, Ana Maria

    2016-01-22

    We propose the use of optical lattice clocks operated with fermionic alkaline-earth atoms to study spin-orbit coupling (SOC) in interacting many-body systems. The SOC emerges naturally during the clock interrogation, when atoms are allowed to tunnel and accumulate a phase set by the ratio of the "magic" lattice wavelength to the clock transition wavelength. We demonstrate how standard protocols such as Rabi and Ramsey spectroscopy that take advantage of the sub-Hertz resolution of state-of-the-art clock lasers can perform momentum-resolved band tomography and determine SOC-induced s-wave collisions in nuclear-spin-polarized fermions. With the use of a second counterpropagating clock beam, we propose a method for engineering controlled atomic transport and study how it is modified by p- and s-wave interactions. The proposed spectroscopic probes provide clean and well-resolved signatures at current clock operating temperatures.

  16. Bose-Einstein Condensates in Optical Lattices: Experiments

    NASA Astrophysics Data System (ADS)

    Morsch, O.

    In the early days of laser cooling, which together with magnetic trapping techniques led to the first observation of BEC in 1995, it was realized that the optical interference between the cooling beams could lead to a spatially periodic density modulation of the trapped atoms. This notion of a "three-dimensional egg-carton" for cold atoms quickly led to a number of experiments confirming the existence of such a light-bound crystal and exploring its properties [1-3]. It was found that, indeed, cold atoms could be trapped in such periodic structures, and it was possible to measure, for example, the quantized motion of the atoms inside the potential wells. While early experiments were carried out in the dissipative regime using near-resonant lattices in which the atoms were continuously cooled through the Sisyphus mechanism involving light scattering [4], more sophisticated experimental techniques later enabled studies on far-detuned lattices in which atoms evolved coherently.

  17. Energy logistics in an all-optical adder based on a 1D porous silicon photonic crystal

    NASA Astrophysics Data System (ADS)

    Glushko, E. Ya.

    2011-09-01

    The ideology of a photonic crystal resonator covered with optically nonlinear layers is proposed for binary adder and logic gates of various kinds. The all-optical way to transform a physically added sequence of signals into the logical sequence with corresponding shift of digital units is based on the nonlinear band shift effect. In this work, the electromagnetic field structure for optically linear 1D porous silicon photonic crystal is investigated. The optical parameters of a 1D photonic crystal resonator built on layered porous silicon covered with a nonlinear layer are calculated for various nonlinear materials. An approximate design of an all-optical adder based on 1D porous silicon resonator is considered. The adder heating by powered optical pulses and energy distribution inside the device are analyzed and the problem solution with the use of special semitransparent redirecting mirrors is proposed. It was found that from the point of view of heating the R-scheme of signal processing is more optimal.

  18. Universal dynamical phase diagram of lattice spin models and strongly correlated ultracold atoms in optical lattices

    NASA Astrophysics Data System (ADS)

    Demler, E. A.; Maltsev, A. Ya; Prokofiev, A. O.

    2017-06-01

    We study semiclassical dynamics of anisotropic Heisenberg models in two and three dimensions. Such models describe lattice spin systems and hard core bosons in optical lattices. We solve numerically Landau-Lifshitz type equations on a lattice and show that in the phase diagram of magnetization and interaction anisotropy, one can identify several distinct regimes of dynamics. These regions can be distinguished based on the character of one dimensional solitonic excitations, and stability of such solitons to transverse modulation. Small amplitude and long wavelength perturbations can be analyzed analytically using mapping of non-linear hydrodynamic equations to KdV type equations. Numerically we find that properties of solitons and dynamics in general remain similar to our analytical results even for large amplitude and short distance inhomogeneities, which allows us to obtain a universal dynamical phase diagram. As a concrete example we study dynamical evolution of the system starting from a state with magnetization step and show that formation of oscillatory regions and their stability to transverse modulation can be understood from the properties of solitons. In regimes unstable to transverse modulation we observe formation of lump type solutions with modulation in all directions. We discuss implications of our results for experiments with ultracold atoms.

  19. Quantum simulations of lattice gauge theories using ultracold atoms in optical lattices.

    PubMed

    Zohar, Erez; Cirac, J Ignacio; Reznik, Benni

    2016-01-01

    Can high-energy physics be simulated by low-energy, non-relativistic, many-body systems such as ultracold atoms? Such ultracold atomic systems lack the type of symmetries and dynamical properties of high energy physics models: in particular, they manifest neither local gauge invariance nor Lorentz invariance, which are crucial properties of the quantum field theories which are the building blocks of the standard model of elementary particles. However, it turns out, surprisingly, that there are ways to configure an atomic system to manifest both local gauge invariance and Lorentz invariance. In particular, local gauge invariance can arise either as an effective low-energy symmetry, or as an exact symmetry, following from the conservation laws in atomic interactions. Hence, one could hope that such quantum simulators may lead to a new type of (table-top) experiments which will be used to study various QCD (quantum chromodynamics) phenomena, such as the confinement of dynamical quarks, phase transitions and other effects, which are inaccessible using the currently known computational methods. In this report, we review the Hamiltonian formulation of lattice gauge theories, and then describe our recent progress in constructing the quantum simulation of Abelian and non-Abelian lattice gauge theories in 1  +  1 and 2  +  1 dimensions using ultracold atoms in optical lattices.

  20. Optical trapping via guided resonance modes in a Slot-Suzuki-phase photonic crystal lattice.

    PubMed

    Ma, Jing; Martínez, Luis Javier; Povinelli, Michelle L

    2012-03-12

    A novel photonic crystal lattice is proposed for trapping a two-dimensional array of particles. The lattice is created by introducing a rectangular slot in each unit cell of the Suzuki-Phase lattice to enhance the light confinement of guided resonance modes. Large quality factors on the order of 10⁵ are predicted in the lattice. A significant decrease of the optical power required for optical trapping can be achieved compared to our previous design.

  1. Dynamical phase diagram of Gaussian wave packets in optical lattices.

    PubMed

    Hennig, H; Neff, T; Fleischmann, R

    2016-03-01

    We study the dynamics of self-trapping in Bose-Einstein condensates (BECs) loaded in deep optical lattices with Gaussian initial conditions, when the dynamics is well described by the discrete nonlinear Schrödinger equation (DNLSE). In the literature an approximate dynamical phase diagram based on a variational approach was introduced to distinguish different dynamical regimes: diffusion, self-trapping, and moving breathers. However, we find that the actual DNLSE dynamics shows a completely different diagram than the variational prediction. We calculate numerically a detailed dynamical phase diagram accurately describing the different dynamical regimes. It exhibits a complex structure that can readily be tested in current experiments in BECs in optical lattices and in optical waveguide arrays. Moreover, we derive an explicit theoretical estimate for the transition to self-trapping in excellent agreement with our numerical findings, which may be a valuable guide as well for future studies on a quantum dynamical phase diagram based on the Bose-Hubbard Hamiltonian.

  2. Proposals for quantum simulating simple lattice gauge theory models using optical lattices

    NASA Astrophysics Data System (ADS)

    Zhang, Jin; Unmuth-Yockey, Judah; Bazavov, Alexei; Meurice, Yannick; Tsai, Shan-Wen

    We derive an effective spin Hamiltonian for the (1 +1)-dimensional Abelian Higgs model in the strongly coupled region by integrating out the link variables. With finite spin truncations, the Hamiltonian can be matched with a 1-dimensional two-species Bose Hubbard model in the strong-coupling limit that can be implemented with cold atoms on an optical lattice. We study the phase diagram of the original Abelian Higgs model with Monte Carlo simulation and Tensor Renormalization Group methods. The results show a crossover line which terminates near the Kosterlitz-Thouless transition point. The effective quantum Hamiltonian is also studied with the DMRG method, and we find that they have a similar behavior. We discuss practical experimental implementations for our quantum simulator. Species-dependent optical lattices and ladder systems with double-well potentials are considered. We show how to obtain each of the interaction parameters required in the Bose-Hubbard model that we obtained, and confirm the possibility of tuning these interactions to the region in which our mapping is valid. We emphasize that this proposal for quantum simulating a gauge theory uses a manifestly gauge-invariant formulation and Gauss's Law is therefore automatically satisfied. Supported by DoD ARO under Grant No. W911NF-13-1-0119 and by the NSF under Grants No. DMR-1411345.

  3. Bandwidth-resonant Floquet states in honeycomb optical lattices

    NASA Astrophysics Data System (ADS)

    Quelle, A.; Goerbig, M. O.; Morais Smith, C.

    2016-01-01

    We investigate, within Floquet theory, topological phases in the out-of-equilibrium system that consists of fermions in a circularly shaken honeycomb optical lattice. We concentrate on the intermediate regime, in which the shaking frequency is of the same order of magnitude as the band width, such that adjacent Floquet bands start to overlap, creating a hierarchy of band inversions. It is shown that two-phonon resonances provide a topological phase that can be described within the Bernevig-Hughes-Zhang model of HgTe quantum wells. This allows for an understanding of out-of-equilibrium topological phases in terms of simple band inversions, similar to equilibrium systems.

  4. Unveiling square and triangular optical lattices: a comparative study.

    PubMed

    Silva, Juarez G; Jesus-Silva, Alcenísio J; Alencar, Márcio A R C; Hickmann, Jandir M; Fonseca, Eduardo J S

    2014-02-15

    We study square and triangular optical lattice formation using a diffraction technique with light-possessing orbital angular momentum (OAM). We demonstrate that it is possible to use Fraunhofer diffraction of light by a square aperture to unveil OAM about two times bigger than would be possible with a triangular aperture. We notice that the pattern remains truncated until a topological charge (TC) equal to 20 with good precision. Even though a square pattern cannot be used to determine the TC sign, it is possible to measure high order of the modulus and sign of the TC up to 20, combining patterns of the triangular and square apertures.

  5. Defect-mediated discrete solitons in optically induced photorefractive lattices

    SciTech Connect

    Li Yongyao; Pang Wei; Chen Yongzhu; Yu Zhiqiang; Zhou Jianying; Zhang Huarong

    2009-10-15

    Theoretical analysis to the defect mediated discrete solitons in one- and two-dimensional periodical waveguide lattices is presented. The waveguide arrays with these functional defects are assumed to respond to the light field as an optically induced photorefraction and they are patterned by a holographic technique. It is found that the spatial energy distributions of the solitary waves can be controlled by the defects in the waveguide arrays, and this gives rise to an additional freedom to externally shaping the light field distribution to a special shape.

  6. Fermions in Optical Lattices Swept across Feshbach Resonances

    SciTech Connect

    Diener, Roberto B.; Ho, T.-L.

    2006-01-13

    We point out that the recent experiments at ETH on fermions in optical lattices, where a band insulator evolves continuously into states occupying many bands as the system is swept adiabatically across Feshbach resonance, have implications on a wide range of fundamental issues in condensed matter. We derive the effective Hamiltonian of these systems, obtain expressions for their energies and band populations, and point out the increasing quantum entanglement of the ground state during the adiabatic sweep. Our results also explain why only specific regions in k space can be populated after the sweep as found at ETH.

  7. Wilson Fermions and Axion Electrodynamics in Optical Lattices

    SciTech Connect

    Bermudez, A.; Martin-Delgado, M. A.; Mazza, L.; Rizzi, M.; Goldman, N.; Lewenstein, M.

    2010-11-05

    We show that ultracold Fermi gases in optical superlattices can be used as quantum simulators of relativistic lattice fermions in 3+1 dimensions. By exploiting laser-assisted tunneling, we find an analogue of the so-called naive Dirac fermions, and thus provide a realization of the fermion doubling problem. Moreover, we show how to implement Wilson fermions, and discuss how their mass can be inverted by tuning the laser intensities. In this regime, our atomic gas corresponds to a phase of matter where Maxwell electrodynamics is replaced by axion electrodynamics: a 3D topological insulator.

  8. Metastable superfluidity of repulsive fermionic atoms in optical lattices.

    PubMed

    Rosch, Achim; Rasch, David; Binz, Benedikt; Vojta, Matthias

    2008-12-31

    In the fermionic Hubbard model, doubly occupied states have an exponentially large lifetime for strong repulsive interactions U. We show that this property can be used to prepare a metastable s-wave superfluid state for fermionic atoms in optical lattices described by a large-U Hubbard model. When an initial band-insulating state is expanded, the doubly occupied sites Bose condense. A mapping to the ferromagnetic Heisenberg model in an external field allows for a reliable solution of the problem. Nearest-neighbor repulsion and pair hopping are important in stabilizing superfluidity.

  9. Wilson fermions and axion electrodynamics in optical lattices.

    PubMed

    Bermudez, A; Mazza, L; Rizzi, M; Goldman, N; Lewenstein, M; Martin-Delgado, M A

    2010-11-05

    We show that ultracold Fermi gases in optical superlattices can be used as quantum simulators of relativistic lattice fermions in 3+1 dimensions. By exploiting laser-assisted tunneling, we find an analogue of the so-called naive Dirac fermions, and thus provide a realization of the fermion doubling problem. Moreover, we show how to implement Wilson fermions, and discuss how their mass can be inverted by tuning the laser intensities. In this regime, our atomic gas corresponds to a phase of matter where Maxwell electrodynamics is replaced by axion electrodynamics: a 3D topological insulator.

  10. Ultracold Heteronuclear Molecules in a 3D Optical Lattice

    SciTech Connect

    Ospelkaus, C.; Ospelkaus, S.; Humbert, L.; Ernst, P.; Sengstock, K.; Bongs, K.

    2006-09-22

    We report on the creation of ultracold heteronuclear molecules assembled from fermionic {sup 40}K and bosonic {sup 87}Rb atoms in a 3D optical lattice. Molecules are produced at a heteronuclear Feshbach resonance on both the attractive and the repulsive sides of the resonance. We precisely determine the binding energy of the heteronuclear molecules from rf spectroscopy across the Feshbach resonance. We characterize the lifetime of the molecular sample as a function of magnetic field and measure lifetimes between 20 and 120 ms. The efficiency of molecule creation via rf association is measured and is found to decrease as expected for more deeply bound molecules.

  11. Self-guiding of matter waves in optical lattices

    SciTech Connect

    Alexander, Tristram J.

    2011-04-15

    It is shown numerically that Bose-Einstein condensates in optical lattices may be localized as self-induced waveguides and that these waveguides may take complex forms, including bends and X junctions. The waveguides are found to support continuous condensate flow, even around multiple right-angle bends. It is demonstrated that pulsed matter-wave transport may also occur along single-site waveguides in the form of solitons and that these solitons may propagate around bends and collide without change of shape or dependence on phase. A scheme based on single-site addressability techniques and the Kibble-Zurek mechanism is proposed for observing these effects.

  12. Quantum Engineering of Dynamical Gauge Fields on Optical Lattices

    DTIC Science & Technology

    2016-07-08

    For the Abelian Higgs model, an on-site term that converts bosons of one species into another species is needed [2]. This requirement rules out...classical O(2) model in 1+1 dimensions to a boson model that can be implemented on optical lattices, showing a proof-of-principle that quantum computing...first constructed a sequence of theoretical steps connecting the classical O(2) model in 1+1 dimensions to a boson model that can be implemented on

  13. Optical lattice clocks near the QPN limit: a tenfold improvement in optical clock stability

    NASA Astrophysics Data System (ADS)

    Nicholson, Travis

    2013-05-01

    Two classes of optical atomic clocks have surpassed microwave frequency standards: single-ion clocks and optical lattice clocks. Single-ion clocks hold the record for the lowest systematic uncertainty; however, many-atom lattice clocks have the potential to outperform single-ion clocks because the standard quantum limit to atomic clock instability (known as quantum projection noise or QPN) scales as 1 /√{Natoms}. For realistic atom numbers and coherence times, QPN-limited lattice clocks could average down to a given stability hundreds of times faster than the best ion clocks. Up to now lattice clocks with 1000 atoms have not shown improvement over the stability of single-ion clocks. Lattice clock stability has been limited by laser noise (via the optical Dick effect). To address this problem, we constructed a new clock laser with a thermal noise floor of 1 ×10-16 -an order of magnitude improvement over our previous clock laser. With this laser, we compare two lattice clocks, reaching instability of 1 ×10-17 in 2000 s for a single clock. This instability is within a factor of 2 of the theoretical QPN limit for 1000 atoms, representing the lowest reported instability for an independent clock. The high stability of many-particle clocks can come at the price of larger systematic uncertainty due to a frequency shift from atomic interactions. To minimize this shift, we use a cavity-enhanced lattice for our second clock. The high circulating power inside the cavity allows for a large trap volume, yielding a density at 2000 atoms that is 27 times smaller (than in our first clock) and permitting us to trap as many as 5 ×104 atoms. For 2000 atoms in our lattice, we measure a value for this shift (which is linear in density) of - 3 . 11 ×10-17 with an uncertainty of 8 . 2 ×10-19.

  14. Effective theory of interacting fermions in shaken square optical lattices

    NASA Astrophysics Data System (ADS)

    Keleş, Ahmet; Zhao, Erhai; Liu, W. Vincent

    2017-06-01

    We develop a theory of weakly interacting fermionic atoms in shaken optical lattices based on the orbital mixing in the presence of time-periodic modulations. Specifically, we focus on fermionic atoms in a circularly shaken square lattice with near-resonance frequencies, i.e., tuned close to the energy separation between the s band and the p bands. First, we derive a time-independent four-band effective Hamiltonian in the noninteracting limit. Diagonalization of the effective Hamiltonian yields a quasienergy spectrum consistent with the full numerical Floquet solution that includes all higher bands. In particular, we find that the hybridized s band develops multiple minima and therefore nontrivial Fermi surfaces at different fillings. We then obtain the effective interactions for atoms in the hybridized s band analytically and show that they acquire momentum dependence on the Fermi surface even though the bare interaction is contactlike. We apply the theory to find the phase diagram of fermions with weak attractive interactions and demonstrate that the pairing symmetry is s +d wave. Our theory is valid for a range of shaking frequencies near resonance, and it can be generalized to other phases of interacting fermions in shaken lattices.

  15. Optical Lattice Induced Light Shifts in an Yb Atomic Clock

    SciTech Connect

    Barber, Z. W.; Stalnaker, J. E.; Lemke, N. D.; Poli, N.; Oates, C. W.; Fortier, T. M.; Diddams, S. A.; Hollberg, L.; Hoyt, C. W.; Taichenachev, A. V.; Yudin, V. I.

    2008-03-14

    We present an experimental study of the lattice-induced light shifts on the {sup 1}S{sub 0}{yields}{sup 3}P{sub 0} optical clock transition ({nu}{sub clock}{approx_equal}518 THz) in neutral ytterbium. The 'magic' frequency {nu}{sub magic} for the {sup 174}Yb isotope was determined to be 394 799 475(35) MHz, which leads to a first order light shift uncertainty of 0.38 Hz. We also investigated the hyperpolarizability shifts due to the nearby 6s6p{sup 3}P{sub 0}{yields}6s8p{sup 3}P{sub 0}, 6s8p{sup 3}P{sub 2}, and 6s5f{sup 3}F{sub 2} two-photon resonances at 759.708, 754.23, and 764.95 nm, respectively. By measuring the corresponding clock transition shifts near these two-photon resonances, the hyperpolarizability shift was estimated to be 170(33) mHz for a linear polarized, 50 {mu}K deep, lattice at the magic wavelength. These results indicate that the differential polarizability and hyperpolarizability frequency shift uncertainties in a Yb lattice clock could be held to well below 10{sup -17}.

  16. Bose-Einstein condensation in a frustrated triangular optical lattice

    NASA Astrophysics Data System (ADS)

    Janzen, Peter; Huang, Wen-Min; Mathey, L.

    2016-12-01

    The recent experimental condensation of ultracold atoms in a triangular optical lattice with a negative effective tunneling parameter paves the way for the study of frustrated systems in a controlled environment. Here, we explore the critical behavior of the chiral phase transition in such a frustrated lattice in three dimensions. We represent the low-energy action of the lattice system as a two-component Bose gas corresponding to the two minima of the dispersion. The contact repulsion between the bosons separates into intra- and intercomponent interactions, referred to as V0 and V12, respectively. We first employ a Huang-Yang-Luttinger approximation of the free energy. For V12/V0=2 , which corresponds to the bare interaction, this approach suggests a first-order phase transition, at which both the U (1 ) symmetry of condensation and the Z2 symmetry of the emergent chiral order are broken simultaneously. Furthermore, we perform a renormalization-group calculation at one-loop order. We demonstrate that the coupling regime 0 1 we show that V0 flows to a negative value, while V12 increases and remains positive. This results in a breakdown of the effective quartic-field theory due to a cubic anisotropy and, again, suggests a discontinuous phase transition.

  17. Quantum state control and characterization in an optical lattice

    NASA Astrophysics Data System (ADS)

    Myrskog, Stefan Henrik

    In this dissertation I present experimental work on the measurement and manipulation of the center-of-mass motion of laser-cooled atoms. The first experiment described demonstrates cooling of an atom cloud by 'delta-kick cooling'. A thermal cloud of atoms in a vacuum expands ballistically, generating correlations between position and momentum. An appropriate momentum kick, proportional to position, results in slowing down all the atoms in the cloud. Through this technique a cloud of atoms can be cooled by greater than a factor of 10, preserving phase-space density, but decreasing the number density of atoms. By using laser-cooled atoms, it is also possible to confine atoms in potentials created by the AC-Stark shift of the atomic energy levels. Using interfering lasers to create the Stark shift, atoms are confined in a sinusoidal potential called an optical lattice. After preparing atoms in the lowest-energy band of the lattice, a spatial displacement can create coherent superpositions of many states of the potential. A combination of time delays and secondary displacements allows the measurement of the Q (Husimi) and W (Wigner) quasi-probability distributions, each of which completely characterizes the motional state of the atoms. Alternatively, a shallow lattice that only support two long-lived states can be used. The two-state system may be characterized with far fewer measurements, and furthermore, can be used as a model system for a qubit, a quantum representation of a single bit of information, useful for quantum computation. We demonstrate reconstruction of the density matrix in the 2-state system. The two-state system has be further used to characterize the physical action of an operation. By preparing a complete set of input density matrices we perform quantum process tomography for the intrinsic decoherence of the lattice, and two operations that correspond to single qubit rotations.

  18. Management of matter waves in optical lattices by means of the Feshbach resonance

    SciTech Connect

    Brazhnyi, V.A.; Konotop, V. V.

    2005-09-15

    The mean-field dynamics of Bose-Einstein condensates loaded in an optical lattice, confined by a parabolic potential, and subjected to a change of scattering length by means of the Feshbach resonance is considered. The system is described by the Gross-Pitaevskii (GP) equation with varying nonlinearity, which in a number of cases is reduced to one-dimensional (1D) perturbed nonlinear Schroedinger (NLS) equations, the particular form of which depends on the relation among the parameters of the problem. We analytically describe the adiabatic dynamics of periodic solutions of the respective NLS equations, provide a numerical study of 1D models confined by a parabolic trap, and carry out numerical simulations of the matter-wave dynamics within the framework of the radially symmetric 3D GP equation. Special attention is paid to processes of generation of trains of bright and dark matter solitons from initially periodic waves. The results of the 1D approximation are compared with direct numerical simulation of the original 3D GP eqation, showing remarkable coincidence for definite regions of parameters.

  19. Stability improvements for the NIST Yb optical lattice clock

    NASA Astrophysics Data System (ADS)

    Fasano, R. J.; Schioppo, M.; McGrew, W. F.; Brown, R. C.; Hinkley, N.; Yoon, T. H.; Beloy, K.; Oates, C. W.; Ludlow, A. D.

    2016-05-01

    To reach the fundamental limit given by quantum projection noise, optical lattice clocks require advanced laser stabilization techniques. The NIST ytterbium clock has benefited from several generations of extremely high finesse optical cavities, with cavity linewidths below 1 kHz. Characterization of the cavity drift rate has allowed compensation to the mHz/s level, improving the medium-term stability of the cavity. Based on recent measurements using Ramsey spectroscopy with synchronous interrogation, we report a fractional instability σy(1s) <=10-16 , dominated by atom number fluctuation noise. We also provide updates on our cryogenic sapphire cavity with a reduced thermal noise floor, which will improve our Dick-limited fractional instability at 1 s to below 10-16. Also at University of Colorado.

  20. Subwavelength optical lattices induced by position-dependent dark states

    SciTech Connect

    Sun Qingqing; Evers, Joerg; Kiffner, Martin; Zubairy, M. Suhail

    2011-05-15

    A method for the generation of subwavelength optical lattices based on multilevel dark states is proposed. The dark state is formed by a suitable combination of standing wave light fields, leading to position-dependent populations of the ground states. An additional field coupling dispersively to one of the ground states translates this position dependence into a subwavelength optical potential. We provide two semiclassical approaches to understand the involved physics, and demonstrate that they lead to identical results in a certain meaningful limit. Then we apply a Monte Carlo simulation technique to study the full quantum dynamics of the subwavelength trapping. Finally, we discuss the relevant time scales for the trapping, optimum conditions, and possible implementations.

  1. Simulation of non-resonant gas-optical lattice interaction

    NASA Astrophysics Data System (ADS)

    Kungurtsev, P. V.; Shevyrin, A. A.; Bondar, Ye. A.; Kashkovsky, A. V.; Gimelshein, S. F.; Shneider, M. N.

    2016-10-01

    Self-consistent interaction of a non-resonant optical lattice with a gas of polarizable particles is considered. We investigate periodic modulations of gas density in the field of high-intensity laser radiation from two opposing sources and potential's evolution due to intense Bragg reflection. The self-consistent model of laser field and gas interaction is developed and implemented into the SMILE++ software system based on the Direct Simulation Monte Carlo method. We observed noticeable variation of the force acting on the particles in the interaction region, especially in its central part. Taking into account the arising spatial inhomogeneity of the optical potential we demonstrated noticeable effects on the evolution of the self-consistent system if the interaction region has a macroscopic size.

  2. Accurate Optical Lattice Clock with {sup 87}Sr Atoms

    SciTech Connect

    Le Targat, Rodolphe; Baillard, Xavier; Fouche, Mathilde; Brusch, Anders; Tcherbakoff, Olivier; Rovera, Giovanni D.; Lemonde, Pierre

    2006-09-29

    We report a frequency measurement of the {sup 1}S{sub 0}-{sup 3}P{sub 0} transition of {sup 87}Sr atoms in an optical lattice clock. The frequency is determined to be 429 228 004 229 879(5) Hz with a fractional uncertainty that is comparable to state-of-the-art optical clocks with neutral atoms in free fall. The two previous measurements of this transition were found to disagree by about 2x10{sup -13}, i.e., almost 4 times the combined error bar and 4 to 5 orders of magnitude larger than the claimed ultimate accuracy of this new type of clocks. Our measurement is in agreement with one of these two values and essentially resolves this discrepancy.

  3. Observation of optical solitons in PT-symmetric lattices

    PubMed Central

    Wimmer, Martin; Regensburger, Alois; Miri, Mohammad-Ali; Bersch, Christoph; Christodoulides, Demetrios N.; Peschel, Ulf

    2015-01-01

    Controlling light transport in nonlinear active environments is a topic of considerable interest in the field of optics. In such complex arrangements, of particular importance is to devise strategies to subdue chaotic behaviour even in the presence of gain/loss and nonlinearity, which often assume adversarial roles. Quite recently, notions of parity-time (PT) symmetry have been suggested in photonic settings as a means to enforce stable energy flow in platforms that simultaneously employ both amplification and attenuation. Here we report the experimental observation of optical solitons in PT-symmetric lattices. Unlike other non-conservative nonlinear arrangements where self-trapped states appear as fixed points in the parameter space of the governing equations, discrete PT solitons form a continuous parametric family of solutions. The possibility of synthesizing PT-symmetric saturable absorbers, where a nonlinear wave finds a lossless path through an otherwise absorptive system is also demonstrated. PMID:26215165

  4. Exact matter-wave vortices in a driven optical lattice

    NASA Astrophysics Data System (ADS)

    Deng, Yan; Hai, Wenhua; Zhou, Zheng

    2013-07-01

    We investigate vortex dynamics of a periodically driven Bose-Einstein condensate confined in a spatially two-dimensional optical lattice. An exact Floquet solution of the Gross-Pitaevskii equation is obtained for a certain parameter region which can be divided into the phase-jumping and phase-continuing regions. In the former region, the exact solution can describe spatiotemporal evolution of multiple vortices. For a small ratio of driving strength to optical lattice depth the vortices keep nearly unmoved. With the increase of the ratio, the vortices undergo an effective interaction and periodically evolve along some fixed circular orbits that leads the vortex dipoles and quadrupoles to produce and break alternatively. There is a critical ratio in the phase-jumping region beyond which the vortices generate and melt periodically. In the phase-continuing region, the condensate in the exact Floquet state evolves periodically without zero-density nodes. It is numerically demonstrated that the exact solution is stable under an initial perturbation for both parameter regions, except for a subregion of the phase-jumping region in which stability of the condensate is lost. However, the solution is structurally stable under a small parameter perturbation only for the phase-continuing region, while for the whole phase-jumping region the structural stability is destroyed. The results suggest a scheme for creating and controlling matter-wave vortices.

  5. Split and overlapped binary solitons in optical lattices

    NASA Astrophysics Data System (ADS)

    Sekh, Golam Ali; Pepe, Francesco V.; Facchi, Paolo; Pascazio, Saverio; Salerno, Mario

    2015-07-01

    We analyze the energetic and dynamical properties of bright-bright (BB) soliton pairs in a binary mixture of Bose-Einstein condensates subjected to the action of a combined optical lattice, acting as an external potential for the first species while modulating the intraspecies coupling constant of the second. In particular, we use a variational approach and direct numerical integrations to investigate the existence and stability of bright-bright (BB) solitons in which the two species are either spatially separated (split soliton) or located at the same optical lattice site (overlapped soliton). The dependence of these solitons on the interspecies interaction parameter is explicitly investigated. For repulsive interspecies interaction we show the existence of a series of critical values at which transitions from an initially overlapped soliton to split solitons occur. For attractive interspecies interaction only single direct transitions from split to overlapped BB solitons are found. The possibility to use split solitons for indirect measurements of scattering lengths is also suggested.

  6. Coherent control of atomic transport in spinor optical lattices

    SciTech Connect

    Mischuck, Brian; Deutsch, Ivan H.; Jessen, Poul S.

    2010-02-15

    Coherent transport of atoms trapped in an optical lattice can be controlled by microwave-induced spin flips that correlate with site-to-site hopping. We study the controllability of homogeneous one-dimensional systems of noninteracting atoms in the absence of site addressability. Given these restrictions, we construct a deterministic protocol to map an initially localized Wannier state to a wave packet that is coherently distributed over n sites. As an example, we consider a one dimensional quantum walk in the presence of both realistic photon scattering and inhomogeneous broadening of the microwave transition due to the optical lattice. Using composite pulses to suppress errors, fidelities of over 95% can be achieved for a 25-step walk. We extend the protocol for state preparation to analytic solutions for arbitrary unitary maps given homogeneous systems and in the presence of time-dependent uniform forces. Such control is important for applications in quantum information processing, such as quantum computing and quantum simulations of condensed matter phenomena.

  7. Proposal for generating synthetic magnetic fields in hexagonal optical lattices

    NASA Astrophysics Data System (ADS)

    Tian, Binbin; Endres, Manuel; Pekker, David

    2015-05-01

    We propose a new approach to generating synthetic magnetic fields in ultra cold atom systems that does not rely on either Raman transitions nor periodic drive. Instead, we consider a hexagonal optical lattice produced by the intersection of three laser beams at 120 degree angles, where the intensity of one or more of the beams is spatially non-uniform. The resulting optical lattice remains hexagonal, but has spatially varying hopping matrix elements. For atoms near the Dirac points, these spatial variations appear as a gauge field, similar to the fictitious gauge field that is induced for for electrons in strained graphene. We suggest that a robust way to generate a gauge field that corresponds to a uniform flux is to aligning three gaussian beams to intersect in an equilateral triangle. Using realistic experimental parameters, we show how the proposed setup can be used to observe cyclotron motion of an atom cloud - the conventional Hall effect and distinct Landau levels - the integer quantum Hall effect.

  8. Probing many-body interactions in an optical lattice clock

    NASA Astrophysics Data System (ADS)

    Rey, A. M.; Gorshkov, A. V.; Kraus, C. V.; Martin, M. J.; Bishof, M.; Swallows, M. D.; Zhang, X.; Benko, C.; Ye, J.; Lemke, N. D.; Ludlow, A. D.

    2014-01-01

    We present a unifying theoretical framework that describes recently observed many-body effects during the interrogation of an optical lattice clock operated with thousands of fermionic alkaline earth atoms. The framework is based on a many-body master equation that accounts for the interplay between elastic and inelastic p-wave and s-wave interactions, finite temperature effects and excitation inhomogeneity during the quantum dynamics of the interrogated atoms. Solutions of the master equation in different parameter regimes are presented and compared. It is shown that a general solution can be obtained by using the so called Truncated Wigner Approximation which is applied in our case in the context of an open quantum system. We use the developed framework to model the density shift and decay of the fringes observed during Ramsey spectroscopy in the JILA 87Sr and NIST 171Yb optical lattice clocks. The developed framework opens a suitable path for dealing with a variety of strongly-correlated and driven open-quantum spin systems.

  9. Gravitational wave detection with optical lattice atomic clocks

    NASA Astrophysics Data System (ADS)

    Kolkowitz, S.; Pikovski, I.; Langellier, N.; Lukin, M. D.; Walsworth, R. L.; Ye, J.

    2016-12-01

    We propose a space-based gravitational wave (GW) detector consisting of two spatially separated, drag-free satellites sharing ultrastable optical laser light over a single baseline. Each satellite contains an optical lattice atomic clock, which serves as a sensitive, narrowband detector of the local frequency of the shared laser light. A synchronized two-clock comparison between the satellites will be sensitive to the effective Doppler shifts induced by incident GWs at a level competitive with other proposed space-based GW detectors, while providing complementary features. The detected signal is a differential frequency shift of the shared laser light due to the relative velocity of the satellites, and the detection window can be tuned through the control sequence applied to the atoms' internal states. This scheme enables the detection of GWs from continuous, spectrally narrow sources, such as compact binary inspirals, with frequencies ranging from ˜3 mHz - 10 Hz without loss of sensitivity, thereby bridging the detection gap between space-based and terrestrial optical interferometric GW detectors. Our proposed GW detector employs just two satellites, is compatible with integration with an optical interferometric detector, and requires only realistic improvements to existing ground-based clock and laser technologies.

  10. Beam evolutions of solitons in strongly nonlocal media with fading optical lattices

    NASA Astrophysics Data System (ADS)

    Dai, Zhi-Ping; Lu, Shi-Zhuan; You, Kai-Ming

    2013-01-01

    We address the impact of imprinted fading optical lattices on the beam evolution of solitons in strongly nonlocal nonlinear media. The results show that the width of the soliton experiences a change with the increasing propagation distance, the critical power for the soliton varies with the lattice fading away, and the soliton breathing is affected by the initial lattice depth and the nonlocality degree.

  11. Ultraviolet laser spectroscopy of neutral mercury in a one-dimensional optical lattice

    SciTech Connect

    Mejri, S.; McFerran, J. J.; Yi, L.; Le Coq, Y.; Bize, S.

    2011-09-15

    We present details on the ultraviolet lattice spectroscopy of the (6s{sup 2}) {sup 1}S{sub 0}{r_reversible} (6s6p) {sup 3}P{sub 0} transition in neutral mercury, specifically {sup 199}Hg. Mercury atoms are loaded into a one-dimensional vertically aligned optical lattice from a magneto-optical trap with an rms temperature of {approx}60 {mu}K. We describe aspects of the magneto-optical trapping, the lattice cavity design, and the techniques employed to trap and detect mercury in an optical lattice. The clock-line frequency dependence on lattice depth is measured at a range of lattice wavelengths. We confirm the magic wavelength to be 362.51(0.16) nm. Further observations to those reported by Yi et al.[Phys. Rev. Lett. 106, 073005 (2011)] are presented regarding the laser excitation of a Wannier-Stark ladder of states.

  12. Quasiparticle Spectrum of 2-d Dirac Vortices in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Haddad, Laith

    2009-10-01

    Bose-Einstein condensates in a honeycomb optical lattice are described by a nonlinear Dirac equaton (NLDE) in the long wavelength, mean field limit [1]. The upper and lower two-spinor equations decouple and superficially resemble the equations of previously studied NLDE's such as the Soler model for extended fermions. Although much work has been done on NLDE's, the bulk of the literature deals with models with Poincare invariant nonlinearites. In contrast our equations break Poincare symmetry providing an opportunity to study phenomenological models in cosmology and particle physics where this symmetry is not manifest. We obtain and classify localized solutions to our equations for both repulsive and attractive contact interactions. We also derive analogs of the Bogoliubov-de Gennes equations for the lattice and use these to study the stability and low energy spectrum of our solutions showing the existence of stable exotic structures such as vortices with fractional statistics.[4pt] [1] L. H. Haddad and L. D. Carr, ``The Nonlinear Dirac Equation in Bose-Einstein Condensates: Foundation and Symmetries,'' Physica D: Nonlinear Phenomena, v. 238, p. 1413 (2009). http://arxiv.org/pdf/0803.3039v1

  13. State diagrams for harmonically trapped bosons in optical lattices

    SciTech Connect

    Rigol, Marcos; Batrouni, George G.; Rousseau, Valery G.; Scalettar, Richard T.

    2009-05-15

    We use quantum Monte Carlo simulations to obtain zero-temperature state diagrams for strongly correlated lattice bosons in one and two dimensions under the influence of a harmonic confining potential. Since harmonic traps generate a coexistence of superfluid and Mott insulating domains, we use local quantities such as the quantum fluctuations of the density and a local compressibility to identify the phases present in the inhomogeneous density profiles. We emphasize the use of the 'characteristic density' to produce a state diagram that is relevant to experimental optical lattice systems, regardless of the number of bosons or trap curvature and of the validity of the local-density approximation. We show that the critical value of U/t at which Mott insulating domains appear in the trap depends on the filling in the system, and it is in general greater than the value in the homogeneous system. Recent experimental results by Spielman et al. [Phys. Rev. Lett. 100, 120402 (2008)] are analyzed in the context of our two-dimensional state diagram, and shown to exhibit a value for the critical point in good agreement with simulations. We also study the effects of finite, but low (T{<=}t/2), temperatures. We find that in two dimensions they have little influence on our zero-temperature results, while their effect is more pronounced in one dimension.

  14. Measuring Z2 topological invariants in optical lattices using interferometry

    NASA Astrophysics Data System (ADS)

    Grusdt, F.; Abanin, D.; Demler, E.

    2014-04-01

    We propose an interferometric method to measure Z2 topological invariants of time-reversal invariant topological insulators realized with optical lattices in two and three dimensions. We suggest two schemes which both rely on a combination of Bloch oscillations with Ramsey interferometry and can be implemented using standard tools of atomic physics. In contrast to topological Zak phase and Chern number, defined for individual one-dimensional and two-dimensional Bloch bands, the formulation of the Z2 invariant involves at least two Bloch bands related by time-reversal symmetry which one must keep track of in measurements. In one of our schemes this can be achieved by the measurement of Wilson loops, which are non-Abelian generalizations of Zak phases. The winding of their eigenvalues is related to the Z2 invariant. We thereby demonstrate that Wilson loops are not just theoretical concepts but can be measured experimentally. For the second scheme we introduce a generalization of time-reversal polarization which is continuous throughout the Brillouin zone. We show that its winding over half the Brillouin zone yields the Z2 invariant. To measure this winding, our protocol only requires Bloch oscillations within a single band, supplemented by coherent transitions to a second band which can be realized by lattice shaking.

  15. Frequency comparison of optical lattice clocks beyond the Dick limit

    NASA Astrophysics Data System (ADS)

    Takamoto, Masao; Takano, Tetsushi; Katori, Hidetoshi

    2011-05-01

    The supreme accuracy of atomic clocks relies on the universality of atomic transition frequencies. The stability of a clock, meanwhile, measures how quickly the clock's statistical uncertainties are reduced. The ultimate measure of stability is provided by the quantum projection noise, which improves as 1/√N by measuring N uncorrelated atoms. Quantum projection noise limited stabilities have been demonstrated in caesium clocks and in single-ion optical clocks, where the quantum noise overwhelms the Dick effect attributed to local oscillator noise. Here, we demonstrate a synchronous frequency comparison of two optical lattice clocks using 87Sr and 88Sr atoms, respectively, for which the Allan standard deviation reached 1 × 10-17 in an averaging time of 1,600 s by cancelling out the Dick effect to approach the quantum projection noise limit. The scheme demonstrates the advantage of using a large number (N ~ 1,000) of atoms in optical clocks and paves the way to investigating the inherent uncertainties of clocks and relativistic geodesy on a timescale of tens of minutes.

  16. Pressure tuning the lattice and optical response of silver sulfide

    SciTech Connect

    Zhao, Zhao; Wei, Hua; Mao, Wendy L.

    2016-06-27

    Binary transition metal chalcogenides have attracted increasing attention for their unique structural and electronic properties. High pressure is a powerful tool for tuning the lattice and electronic structure of transition metal chalcogenides away from their pristine states. In this work, we systematically studied the in situ structural and optical behavior of silver sulfide (Ag{sub 2}S) under pressure by synchrotron X-ray diffraction and infrared spectroscopy measurements in a diamond anvil cell. Upon compression, Ag{sub 2}S undergoes structural symmetrization accompanied by a series of structural transitions while the crystallographic inequivalence of the two Ag sites is maintained. Electronically, pressure effectively tunes the ambient semiconducting Ag{sub 2}S into a metal at ∼22 GPa. Drude model analysis shows that the optical conductivity evolves significantly, reaching the highest value of 100 Ω{sup −1} cm{sup −1} at ∼40 GPa. Our results highlight the structural and electronic tunability of silver chalcogenides as a function of pressure and suggest the potential of Ag{sub 2}S as a platform for developing optical and opto-electronic applications.

  17. Experimental realization of an optical second with strontium lattice clocks.

    PubMed

    Le Targat, R; Lorini, L; Le Coq, Y; Zawada, M; Guéna, J; Abgrall, M; Gurov, M; Rosenbusch, P; Rovera, D G; Nagórny, B; Gartman, R; Westergaard, P G; Tobar, M E; Lours, M; Santarelli, G; Clairon, A; Bize, S; Laurent, P; Lemonde, P; Lodewyck, J

    2013-01-01

    Progress in realizing the SI second had multiple technological impacts and enabled further constraint of theoretical models in fundamental physics. Caesium microwave fountains, realizing best the second according to its current definition with a relative uncertainty of 2-4 × 10(-16), have already been overtaken by atomic clocks referenced to an optical transition, which are both more stable and more accurate. Here we present an important step in the direction of a possible new definition of the second. Our system of five clocks connects with an unprecedented consistency the optical and the microwave worlds. For the first time, two state-of-the-art strontium optical lattice clocks are proven to agree within their accuracy budget, with a total uncertainty of 1.5 × 10(-16). Their comparison with three independent caesium fountains shows a degree of accuracy now only limited by the best realizations of the microwave-defined second, at the level of 3.1 × 10(-16).

  18. Localization of collisionally inhomogeneous condensates in a bichromatic optical lattice

    SciTech Connect

    Cheng Yongshan; Adhikari, S. K.

    2011-02-15

    By direct numerical simulation and variational solution of the Gross-Pitaevskii equation, we studied the stationary and dynamic characteristics of a cigar-shaped, localized, collisionally inhomogeneous Bose-Einstein condensate trapped in a one-dimensional bichromatic quasiperiodic optical-lattice potential, as used in a recent experiment on the localization of a Bose-Einstein condensate [Roati et al., Nature (London) 453, 895 (2008)]. The effective potential characterizing the spatially modulated nonlinearity is obtained. It is found that the collisional inhomogeneity has influence not only on the central region but also on the tail of the Bose-Einstein condensate. The influence depends on the sign and value of the spatially modulated nonlinearity coefficient. We also demonstrate the stability of the stationary localized state by performing a standard linear stability analysis. Where possible, the numerical results are shown to be in good agreement with the variational results.

  19. Coherent transport of single atoms in optical lattices

    SciTech Connect

    Merkel, Wolfgang; Mack, Holger; Freyberger, Matthias; Kozlov, Victor V.; Schleich, Wolfgang P.; Shore, Bruce W.

    2007-03-15

    We describe a technique for transferring a two-level atom between two adjacent potential wells of an optical lattice, using pairs of pump and Stokes pulses, each resonantly coupling the same pair of internal atomic states to form a Raman transition. Starting from a vibrational eigenstate of one well the atom slowly moves under the action of the pulse pair, to the vibrational eigenstate with the same quantum number in the neighboring well. The transfer takes place in two stages: A conventional stimulated Raman adiabatic passage (STIRAP) technique, in which Stokes precedes pump pulse, is followed by a pulse sequence where pump precedes Stokes and with an inverted sign of the Stokes envelope. In the first step the atom is accelerated toward the adjacent well and in the second step decelerated to the initial vibrational energy. The STIRAP technique avoids the introduction of stochastic motion caused by spontaneous emission from the excited internal atomic state.

  20. General Hubbard Model for Fermions in an Optical Lattice

    NASA Astrophysics Data System (ADS)

    Kestner, Jason; Duan, Luming

    2009-03-01

    For two-component fermions in an optical lattice, an effective general Hubbard model (GHM) with tunable on-site attraction/repulsion and occupation-dependent hopping rates emerges from very general arguments [1]. This model is quite interesting, containing as special cases both the t-J and the XXZ models. However, the experimental range of applicability and the connection between the model parameters and the actual experimental parameters must be determined explicitly. To this end, we have used a stochastic variational approach with a correlated gaussian wavefunction to numerically find the eigenstates of two atoms interacting in a 3D few-well trap. By matching the few-site spectrum of the GHM to the variational spectrum obtained, the validity of the model and the relationship between experimental and model parameters are determined. [1] L.-M. Duan, Euro. Phys. Lett. 81, 20001 (2008).

  1. Colloquium: Atomic quantum gases in periodically driven optical lattices

    NASA Astrophysics Data System (ADS)

    Eckardt, André

    2017-01-01

    Time-periodic forcing in the form of coherent radiation is a standard tool for the coherent manipulation of small quantum systems like single atoms. In the last years, periodic driving has more and more also been considered as a means for the coherent control of many-body systems. In particular, experiments with ultracold quantum gases in optical lattices subjected to periodic driving in the lower kilohertz regime have attracted much attention. Milestones include the observation of dynamic localization, the dynamic control of the quantum phase transition between a bosonic superfluid and a Mott insulator, as well as the dynamic creation of strong artificial magnetic fields and topological band structures. This Colloquium reviews these recent experiments and their theoretical description. Moreover, fundamental properties of periodically driven many-body systems are discussed within the framework of Floquet theory, including heating, relaxation dynamics, anomalous topological edge states, and the response to slow parameter variations.

  2. Quantum simulations with ultracold atoms in optical lattices.

    PubMed

    Gross, Christian; Bloch, Immanuel

    2017-09-08

    Quantum simulation, a subdiscipline of quantum computation, can provide valuable insight into difficult quantum problems in physics or chemistry. Ultracold atoms in optical lattices represent an ideal platform for simulations of quantum many-body problems. Within this setting, quantum gas microscopes enable single atom observation and manipulation in large samples. Ultracold atom-based quantum simulators have already been used to probe quantum magnetism, to realize and detect topological quantum matter, and to study quantum systems with controlled long-range interactions. Experiments on many-body systems out of equilibrium have also provided results in regimes unavailable to the most advanced supercomputers. We review recent experimental progress in this field and comment on future directions. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  3. Dynamics of pattern-loaded fermions in bichromatic optical lattices

    NASA Astrophysics Data System (ADS)

    Reichl, Matthew D.; Mueller, Erich J.

    2016-03-01

    Motivated by experiments in Munich [M. Schreiber et al., Science 349, 842 (2015)., 10.1126/science.aaa7432], we study the dynamics of interacting fermions initially prepared in charge density wave states in one-dimensional bichromatic optical lattices. The experiment sees a marked lack of thermalization, which has been taken as evidence for an interacting generalization of Anderson localization, dubbed "many-body localization." We model the experiments using an interacting Aubry-Andre model and develop a computationally efficient low-density cluster expansion to calculate the even-odd density imbalance as a function of interaction strength and potential strength. Our calculations agree with the experimental results and shed light on the phenomena. We also explore a two-dimensional generalization. The cluster expansion method we develop should have broad applicability to similar problems in nonequilibrium quantum physics.

  4. Simulating the Wess-Zumino Supersymmetry Model in Optical Lattices

    SciTech Connect

    Yu Yue; Yang Kun

    2010-10-08

    We study a cold atom-molecule mixture in two-dimensional optical lattices. We show that, by fine-tuning the atomic and molecular interactions, the Wess-Zumino supersymmetry (SUSY) model in 2+1 dimensions emerges in the low-energy limit and can be simulated in such mixtures. At zero temperature, SUSY is not spontaneously broken, which implies identical relativistic dispersions of the atom and its superpartner, a bosonic diatom molecule. This defining signature of SUSY can be probed by single-particle spectroscopies. Thermal breaking of SUSY at a finite temperature is accompanied by a thermal Goldstone fermion, i.e., phonino excitation. This and other signatures of broken SUSY can also be probed experimentally.

  5. F-wave pairing of cold atoms in optical lattices

    SciTech Connect

    Lee, Wei-Cheng; Wu Congjun; Das Sarma, S.

    2010-11-15

    The tremendous development of cold atom physics has opened up a whole new opportunity to study novel states of matter which are not easily accessible in solid-state systems. Here we propose to realize the f-wave pairing superfluidity of spinless fermions in p{sub x,y}-orbital bands of two-dimensional honeycomb optical lattices. The nontrivial orbital band structure, rather than strong correlation effects, gives rise to the unconventional pairing with the nodal lines of the f-wave symmetry. With a confining harmonic trap, zero-energy Andreev bound states appear around the circular boundary with a sixfold symmetry. The experimental realization and detection of this novel pairing state are feasible.

  6. Orbit, optics and chromaticity correction for PS2 negative momentum compaction lattices

    SciTech Connect

    Papaphilippou,Y.; Barranco, J.; Bartmann, W.; Benedikt, M.; Carli, C.; de Maria, R.; Peggs, S.; Trbojevic, D.

    2009-05-04

    The effect of magnet misalignments in the beam orbit and linear optics functions are reviewed and correction schemes are applied to the negative momentum compaction lattice of PS2. Chromaticity correction schemes are also proposed and tested with respect to off-momentum optics properties. The impact of the correction schemes in the dynamic aperture of the lattice is finally evaluated.

  7. Non-standard Hubbard models in optical lattices: a review.

    PubMed

    Dutta, Omjyoti; Gajda, Mariusz; Hauke, Philipp; Lewenstein, Maciej; Lühmann, Dirk-Sören; Malomed, Boris A; Sowiński, Tomasz; Zakrzewski, Jakub

    2015-06-01

    Originally, the Hubbard model was derived for describing the behavior of strongly correlated electrons in solids. However, for over a decade now, variations of it have also routinely been implemented with ultracold atoms in optical lattices, allowing their study in a clean, essentially defect-free environment. Here, we review some of the vast literature on this subject, with a focus on more recent non-standard forms of the Hubbard model. After giving an introduction to standard (fermionic and bosonic) Hubbard models, we discuss briefly common models for mixtures, as well as the so-called extended Bose-Hubbard models, that include interactions between neighboring sites, next-neighbor sites, and so on. The main part of the review discusses the importance of additional terms appearing when refining the tight-binding approximation for the original physical Hamiltonian. Even when restricting the models to the lowest Bloch band is justified, the standard approach neglects the density-induced tunneling (which has the same origin as the usual on-site interaction). The importance of these contributions is discussed for both contact and dipolar interactions. For sufficiently strong interactions, the effects related to higher Bloch bands also become important even for deep optical lattices. Different approaches that aim at incorporating these effects, mainly via dressing the basis, Wannier functions with interactions, leading to effective, density-dependent Hubbard-type models, are reviewed. We discuss also examples of Hubbard-like models that explicitly involve higher p orbitals, as well as models that dynamically couple spin and orbital degrees of freedom. Finally, we review mean-field nonlinear Schrödinger models of the Salerno type that share with the non-standard Hubbard models nonlinear coupling between the adjacent sites. In that part, discrete solitons are the main subject of consideration. We conclude by listing some open problems, to be addressed in the future.

  8. Controlled mode tuning in 1-D 'RIM' plasmonic crystal trench cavities probed with coupled optical emitters.

    PubMed

    Liu, Tsung-li; Russell, Kasey J; Cui, Shanying; Hu, Evelyn L

    2013-12-02

    We present a design of plasmonic cavities that consists of two sets of 1-D plasmonic crystal reflectors on a plasmonic trench waveguide. A 'reverse image mold' (RIM) technique was developed to pattern high-resolution silver trenches and to embed emitters at the cavity field maximum, and FDTD simulations were performed to analyze the frequency response of the fabricated devices. Distinct cavity modes were observed from the photoluminescence spectra of the organic dye embedded within these cavities. The cavity geometry facilitates tuning of the modes through a change in cavity dimensions. Both the design and the fabrication technique presented could be extended to making trench waveguide-based plasmonic devices and circuits.

  9. New optical scheme for parallel processing of 1D gray images

    NASA Astrophysics Data System (ADS)

    Huang, Guoliang; Jin, Guofan; Wu, Minxian; Yan, Yingbai

    1994-06-01

    Based on mathematical morphology and digital umbra shading and shadowing algorithm, a new scheme for realizing the fundamental morphological operation of one dimensional gray images is proposed. The mathematical formula for the parallel processing of 1D gray images is summarized; some important conclusions of morphological processing from binary images to gray images are obtained. The advantages of this scheme is simple in structure, high resolution in gray level, and good in parallelism. It can raise the speed of performing morphological processing of gray images greatly and obtain more accurate results.

  10. Quantitative Determination of the Hubbard Model Phase Diagram from Optical Lattice Experiments by Two-Parameter Scaling

    SciTech Connect

    Campo, V. L. Jr.; Capelle, K.; Quintanilla, J.; Hooley, C.

    2007-12-14

    We propose an experiment to obtain the phase diagram of the fermionic Hubbard model, for any dimensionality, using cold atoms in optical lattices. It is based on measuring the total energy for a sequence of trap profiles. It combines finite-size scaling with an additional 'finite-curvature scaling' necessary to reach the homogeneous limit. We illustrate its viability in the 1D case, simulating experimental data in the Bethe-ansatz local-density approximation. Including experimental errors, the filling corresponding to the Mott transition can be determined with better than 3% accuracy.

  11. Optical signatures of a hypercritical 1D potential in a 2D Dirac metal

    NASA Astrophysics Data System (ADS)

    Jiang, Bor-Yuan; Ni, Guangxin; Pan, Cheng; Fei, Zhe; Cheng, Bin; Lau, Chun Ning; Bockrath, Marc; Basov, Dimitri; Fogler, Michael

    Generation of quasi-bound states in graphene near strong charged perturbations is a solid-state analog of atomic collapse of superheavy elements or particle production by hypothetical cosmic strings. We show, for the case of a linelike perturbation, that as the perturbation grows in strength, quasi-bound states are generated sequentially. Each of these critical events is signaled by a sharp change in the local optical conductivity. Tunable linelike perturbations can be realized in experiment using nanowire or nanotube electrostatic gates. We report measurements of local conductivity for such systems obtained through near-field optical microscopy.

  12. CP(N - 1) quantum field theories with alkaline-earth atoms in optical lattices

    NASA Astrophysics Data System (ADS)

    Laflamme, C.; Evans, W.; Dalmonte, M.; Gerber, U.; Mejía-Díaz, H.; Bietenholz, W.; Wiese, U.-J.; Zoller, P.

    2016-07-01

    We propose a cold atom implementation to attain the continuum limit of (1 + 1) -d CP(N - 1) quantum field theories. These theories share important features with (3 + 1) -d QCD, such as asymptotic freedom and θ-vacua. Moreover, their continuum limit can be accessed via the mechanism of dimensional reduction. In our scheme, the CP(N - 1) degrees of freedom emerge at low energies from a ladder system of SU(N) quantum spins, where the N spin states are embodied by the nuclear Zeeman states of alkaline-earth atoms, trapped in an optical lattice. Based on Monte Carlo results, we establish that the continuum limit can be demonstrated by an atomic quantum simulation by employing the feature of asymptotic freedom. We discuss a protocol for the adiabatic preparation of the ground state of the system, the real-time evolution of a false θ-vacuum state after a quench, and we propose experiments to unravel the phase diagram at non-zero density.

  13. Cooling fermions in optical lattices by faster entropy redistribution

    NASA Astrophysics Data System (ADS)

    Teles, Rafael P.; Yang, Tsung-Lin; Paiva, Thereza; Scalettar, Richard T.; Natu, Stefan S.; Hulet, Randall G.; Hazzard, Kaden R. A.

    2016-05-01

    Lower entropy for fermions in optical lattices would unlock new quantum phases, including antiferromagnetism and potentially superconductivity. We propose a method to cool these systems at temperatures where conventional methods fail: slowly turning on a tightly focused optical potential transports entropy from the Mott insulator to a metallic entropy reservoir formed along the beam. Our scheme places the entropy reservoir close to the targeted cooling region, which allows entropy redistribution to be effective at lower temperatures than in prior proposals. Furthermore we require only a straightforwardly-applied Gaussian potential. We compute the temperatures achieved with this scheme using an analytic T >> t approximation and, for low T, determinantal quantum Monte Carlo. We optimize the waist and depth of the focused beam, and we find that repulsive potentials cool better than attractive ones. We estimate that the time required for entropy transport under nearly adiabatic conditions at these low temperatures is compatible with the system lifetime. Finally, we explore further improvements to cooling enabled by sophisticated potential engineering, e.g. using a spatial light modulator. Work supported by CNPq.

  14. Development of a strontium optical lattice clock for space applications

    NASA Astrophysics Data System (ADS)

    Singh, Yeshpal

    2016-07-01

    With timekeeping being of paramount importance for modern life, much research and major scientific advances have been undertaken in the field of frequency metrology, particularly over the last few years. New Nobel-prize winning technologies have enabled a new era of atomic clocks; namely the optical clock. These have been shown to perform significantly better than the best microwave clocks reaching an inaccuracy of 1.6x10-18 [1]. With such results being found in large lab based apparatus, the focus now has shifted to portability - to enable the accuracy of various ground based clocks to be measured, and compact autonomous performance - to enable such technologies to be tested in space. This could lead to a master clock in space, improving not only the accuracy of technologies on which modern life has come to require such as GPS and communication networks. But also more fundamentally, this could lead to the redefinition of the second and tests of fundamental physics including applications in the fields of ground based and satellite geodesy, metrology, positioning, navigation, transport and logistics etc. Within the European collaboration, Space Optical Clocks (SOC2) [2-3] consisting of various institutes and industry partners across Europe we have tried to tackle this problem of miniaturisation whilst maintaining stability, accuracy (5x10-17) and robustness whilst keeping power consumption to a minimum - necessary for space applications. We will present the most recent results of the Sr optical clock in SOC2 and also the novel compact design features, new methods employed and outlook. References [1] B. J. Bloom, T. L. Nicholson, J. R. Williams, S. L. Campbell, M. Bishof, X. Zhang, W. Zhang, S. L. Bromley, and J. Ye, "An optical lattice clock with accuracy and stability at the 10-18 level," Nature 506, 71-75 (2014). [2] S. Schiller et al. "Towards Neutral-atom Space Optical Clocks (SOC2): Development of high-performance transportable and breadboard optical clocks and

  15. Stationary and traveling solitons via local dissipation in Bose-Einstein condensates in ring optical lattices

    NASA Astrophysics Data System (ADS)

    Campbell, Russell; Oppo, Gian-Luca

    2016-10-01

    A model of a Bose-Einstein condensate in a ring optical lattice with atomic dissipations applied at a stationary or at a moving location on the ring is presented. The localized dissipation is shown to generate and stabilize both stationary and traveling lattice solitons. Among many localized solutions, we have generated spatially stationary quasiperiodic lattice solitons and a family of traveling lattice solitons with two intensity peaks per potential well with no counterpart in the discrete case. Collisions between traveling and stationary lattice solitons as well as between two traveling lattice solitons display a critical dependence from the lattice depth. Stable counterpropagating solitons in ring lattices can find applications in gyroscope interferometers with ultracold gases.

  16. Nearly-one-dimensional self-attractive Bose-Einstein condensates in optical lattices

    SciTech Connect

    Salasnich, L.; Toigo, F.; Cetoli, A.; Malomed, B. A.

    2007-03-15

    Within the framework of a mean-field description, we investigate atomic Bose-Einstein condensates, with attraction between atoms, under the action of a strong transverse confinement and periodic [optical-lattice (OL)] axial potential. Using a combination of the variational approximation, one-dimensional (1D) nonpolynomial Schroedinger equation, and direct numerical solutions of the underlying 3D Gross-Pitaevskii equation, we show that the ground state of the condensate is a soliton belonging to the semi-infinite band gap of the periodic potential. The soliton may be confined to a single cell of the lattice or extended to several cells, depending on the effective self-attraction strength g (which is proportional to the number of atoms bound in the soliton) and depth of the potential, V{sub 0}, the increase of V{sub 0} leading to strong compression of the soliton. We demonstrate that the OL is an effective tool to control the soliton's shape. It is found that, due to the 3D character of the underlying setting, the ground-state soliton collapses at a critical value of the strength, g=g{sub c}, which gradually decreases with the increase of V{sub 0}; under typical experimental conditions, the corresponding maximum number of {sup 7}Li atoms in the soliton, N{sub max}, ranges between 8000 and 4000. Examples of stable multipeaked solitons are also found in the first finite band gap of the lattice spectrum. The respective critical value g{sub c} again slowly decreases with the increase of V{sub 0}, corresponding to N{sub max}{approx_equal}5000.

  17. Low noise optical lattices for a Li-6 Fermi gas microscope

    NASA Astrophysics Data System (ADS)

    Mazurenko, Anton; Parsons, Maxwell; Chiu, Christie; Huber, Florian; Blatt, Sebastian; Greiner, Markus

    2015-05-01

    We report on recent progress towards single-site resolved imaging of fermions in an optical lattice. Fermionic 6-Li atoms are trapped in an optical lattice 10 μm below a high-quality reference surface in the image plane of a high resolution (NA 0.85) imaging system. We have created a highly intensity-stable optical lattice whose depth remains adjustable over three orders of magnitude. The high optical resolution enables a band mapping technique that allows detection of less than 1000 atoms in the ground band of the lattice. We use this technique to measure the decay of the radial ground band population and find lifetimes up to 70 seconds, limited by spontaneous scattering of lattice light. ARO DARPA OLE, ARO MURI, NSF, AFOSR MURI, and The Moore Foundation.

  18. Lobster eye X-ray optics: Data processing from two 1D modules

    NASA Astrophysics Data System (ADS)

    Nentvich, O.; Urban, M.; Stehlikova, V.; Sieger, L.; Hudec, R.

    2017-07-01

    The X-ray imaging is usually done by Wolter I telescopes. They are suitable for imaging of a small part of the sky, not for all-sky monitoring. This monitoring could be done by a Lobster eye optics which can theoretically have a field of view up to 360 deg. All sky monitoring system enables a quick identification of source and its direction. This paper describes the possibility of using two independent one-dimensional Lobster Eye modules for this purpose instead of Wolter I and their post-processing into an 2D image. This arrangement allows scanning with less energy loss compared to Wolter I or two-dimensional Lobster Eye optics. It is most suitable especially for very weak sources.

  19. Optical bullets in (2+1)D photonic structures and their interaction with localized defects

    NASA Astrophysics Data System (ADS)

    Dohnal, Tomas

    2005-11-01

    This dissertation studies light propagation in Kerr-nonlinear two dimensional waveguides with a Bragg resonant, periodic structure in the propagation direction. The model describing evolution of the electric field envelopes is the system of 2D Nonlinear Coupled Mode Equations (2D CME). The periodic structure induces a range of frequencies (frequency gap) in which linear waves do not propagate. It is shown that, similarly to the ID case of a fiber grating, the 2D nonlinear system supports localized solitary wave solutions, referred to as 2D gap solitons, which have frequencies inside the linear gap and can travel at, any speed smaller than or equal to the speed of light in the corresponding homogeneous medium. Such solutions are constructed numerically via Newton's iteration. Convergence is obtained only near the upper edge of the gap. Gap solitons with a nonzero velocity are constructed by numerically following a bifurcation curve parameterized by the velocity v. It is shown that gap solitons are saddle points of the corresponding Hamiltonian functional and that no (constrained) local minima of the Hamiltonian exist. The linear stability problem is formulated and reasons for the failure of the standard Hamiltonian PDE approach for determining linear stability are discussed. In the second part of the dissertation interaction of 2D gap solitons with localized defects is studied and trapping of slow enough 2D gap solitons is demonstrated. This study builds on [JOSA B 19, 1635 (2002)], where such trapping of 1D gap solitons is considered. Analogously to this 1D problem trapping in the 2D model is explained as a resonant energy transfer into one or more defect modes existent for the particular defect. For special localized defects exact linear modes are found explicitly via the separation of variables. Numerical computation of linear defect modes is used for more general defects. Corresponding nonlinear modes are then constructed via Newton's iteration by following a

  20. Superfluidity of fermions with repulsive on-site interaction in an anisotropic optical lattice near a Feshbach resonance

    NASA Astrophysics Data System (ADS)

    Wang, B.; Duan, L.-M.

    2008-07-01

    We present a numerical study on ground state properties of a one-dimensional (1D) general Hubbard model (GHM) with particle-assisted tunnelling rates and repulsive on-site interaction (positive-U), which describes fermionic atoms in an anisotropic optical lattice near a wide Feshbach resonance. For our calculation, we utilize the time evolving block decimation (TEBD) algorithm, which is an extension of the density matrix renormalization group and provides a well-controlled method for 1D systems. We show that the positive-U GHM, when hole-doped from half-filling, exhibits a phase with coexistence of quasi-long-range superfluid and charge-density-wave orders. This feature is different from the property of the conventional Hubbard model with positive-U, indicating the particle-assisted tunnelling mechanism in GHM brings in qualitatively new physics.

  1. Optical anisotropy of quasi-1D rare-earth silicide nanostructures on Si(001)

    NASA Astrophysics Data System (ADS)

    Chandola, S.; Speiser, E.; Esser, N.; Appelfeller, S.; Franz, M.; Dähne, M.

    2017-03-01

    Rare earth metals are known to interact strongly with Si(001) surfaces to form different types of silicide nanostructures. Using STM to structurally characterize Dy and Tb silicide nanostructures on vicinal Si(001), it will be shown that reflectance anisotropy spectroscopy (RAS) can be used as an optical fingerprint technique to clearly distinguish between the formation of a semiconducting two-dimensional wetting layer and the metallic one-dimensional nanowires. Moreover, the distinctive spectral features can be related to structural units of the nanostructures. RAS spectra of Tb and Dy nanostructures are found to show similar features.

  2. Optical reflectance and omnidirectional bandgaps in Fibonacci quasicrystals type 1-D multilayer structures containing exponentially graded material

    NASA Astrophysics Data System (ADS)

    Singh, Bipin K.; Thapa, Khem B.; Pandey, Praveen C.

    2013-06-01

    A theoretical study of optical reflectance and reflection bands of 1-D photonic quasi-crystals (Fibonacci type arrangement) composed of exponentially graded material is presented. The proposed structures consist of two different layers, one of them is of constant refractive index (L) and the other one is of exponentially graded refractive index (S) dielectric materials. Four different generations (2nd, 3rd, 4th and 5th) of the Fibonacci sequence for 10 periods in one dimension (1-D) are considered and compared in view of their optical reflectance and bandgaps for both TE and TM polarisations. Also, we proposed some heterostructures made by the combination of different Fibonacci generations and their periods to obtain suitable omnidirectional reflection band. We used the transfer matrix method (TMM) to obtain the reflectance, bandgaps and omnidirectional reflectional bandgaps (ODR) of such structures in near infrared spectrum (800-2200 nm) at different angles of incidence. We show that ODR exists in these types of structures. The number of ODRs and total bandgap depend on the Fibonacci generations. Extraordinary ODR bandgaps are obtained in the case of heterostructures formed by the combination of different generations of the Fibonacci sequence. The ODR for these structures is similar to the ODR of photonic crystals containing left-handed materials. This work would be useful to study the Fibonacci type photonic crystals having graded index materials and also it will open new window to design several photonic crystal devices like sensors, reflectors, etc. in the infrared region.

  3. Laser cooling of cesium atoms in far-detuned optical lattices

    NASA Astrophysics Data System (ADS)

    Winoto, Sugiharto Lukman

    1999-11-01

    High-density cold Cesium atoms from a transiently compressed magneto-optical trap (MOT) are loaded into far red-detuned optical lattice traps. A subsequent independent laser cooling of the atoms in the trap is shown to be of the polarization gradient cooling (PGC) type. The PGC produces strong localization of atoms in the periodic anti-nodes of lattice sites corresponding to significant occupation of the lattice vibrational ground states. Adiabatic relaxation of the 3D optical lattice trap results in the highest phase-space density achievable for a large number of atoms through a purely optical method of cooling and trapping. The resulting atom cloud is to be loaded into a conservative optical dipole trap for an experimental search of Cesium Bose- Einstein condensation (BEC) through a method of evaporative cooling in the dipole trap.

  4. Atomic Bloch-Zener oscillations and Stückelberg interferometry in optical lattices.

    PubMed

    Kling, Sebastian; Salger, Tobias; Grossert, Christopher; Weitz, Martin

    2010-11-19

    We report on experiments investigating quantum transport and band interferometry of an atomic Bose-Einstein condensate in an optical lattice with a two-band miniband structure, realized with a Fourier-synthesized optical lattice potential. Bloch-Zener oscillations, the coherent superposition of Bloch oscillations and Landau-Zener tunneling between the two bands, are observed. When the relative phase between paths in different bands is varied, an interference signal is observed, demonstrating the coherence of the dynamics in the miniband system. Measured fringe patterns of this Stückelberg interferometer allow us to interferometrically map out the band structure of the optical lattice over the full Brillouin zone.

  5. Atomic Bloch-Zener Oscillations and Stueckelberg Interferometry in Optical Lattices

    SciTech Connect

    Kling, Sebastian; Salger, Tobias; Grossert, Christopher; Weitz, Martin

    2010-11-19

    We report on experiments investigating quantum transport and band interferometry of an atomic Bose-Einstein condensate in an optical lattice with a two-band miniband structure, realized with a Fourier-synthesized optical lattice potential. Bloch-Zener oscillations, the coherent superposition of Bloch oscillations and Landau-Zener tunneling between the two bands, are observed. When the relative phase between paths in different bands is varied, an interference signal is observed, demonstrating the coherence of the dynamics in the miniband system. Measured fringe patterns of this Stueckelberg interferometer allow us to interferometrically map out the band structure of the optical lattice over the full Brillouin zone.

  6. Lattice-Induced Frequency Shifts in Sr Optical Lattice Clocks at the 10{sup -17} Level

    SciTech Connect

    Westergaard, P. G.; Lodewyck, J.; Lecallier, A.; Millo, J.; Lemonde, P.; Lorini, L.; Burt, E. A.; Zawada, M.

    2011-05-27

    We present a comprehensive study of the frequency shifts associated with the lattice potential in a Sr lattice clock by comparing two such clocks with a frequency stability reaching 5x10{sup -17} after a 1 h integration time. We put the first experimental upper bound on the multipolar M1 and E2 interactions, significantly smaller than the recently predicted theoretical upper limit, and give a 30-fold improved upper limit on the effect of hyperpolarizability. Finally, we report on the first observation of the vector and tensor shifts in a Sr lattice clock. Combining these measurements, we show that all known lattice related perturbations will not affect the clock accuracy down to the 10{sup -17} level, even for lattices as deep as 150 recoil energies.

  7. Effect of substrate on optical bound states in the continuum in 1D photonic structures

    NASA Astrophysics Data System (ADS)

    Sadrieva, Z. F.; Sinev, I. S.; Samusev, A. K.; Iorsh, I. V.; Koshelev, K. L.; Takayama, O.; Malureanu, R.; Lavrinenko, A. V.; Bogdanov, A. A.

    2017-09-01

    Optical bound states in the continuum (BIC) are localized states with energy lying above the light line and having infinite lifetime. Any losses taking place in real systems result in transformation of the bound states into resonant states with finite lifetime. In this work, we analyze properties of BIC in CMOS-compatible one-dimensional photonic structure based on silicon-on-insulator wafer at telecommunication wavelengths, where the absorption of silicon is negligible. We reveal that a high-index substrate could destroy both off-Γ BIC and in-plane symmetry protected at-Γ BIC turning them into resonant states due to leakage into the diffraction channels opening in the substrate.

  8. Subharmonic Shapiro steps of sliding colloidal monolayers in optical lattices

    NASA Astrophysics Data System (ADS)

    Paronuzzi Ticco, Stella V.; Fornasier, Gabriele; Manini, Nicola; Santoro, Giuseppe E.; Tosatti, Erio; Vanossi, Andrea

    2016-04-01

    We investigate theoretically the possibility to observe dynamical mode locking, in the form of Shapiro steps, when a time-periodic potential or force modulation is applied to a two-dimensional (2D) lattice of colloidal particles that are dragged by an external force over an optically generated periodic potential. Here we present realistic molecular dynamics simulations of a 2D experimental setup, where the colloid sliding is realized through the motion of soliton lines between locally commensurate patches or domains, and where the Shapiro steps are predicted and analyzed. Interestingly, the jump between one step and the next is seen to correspond to a fixed number of colloids jumping from one patch to the next, across the soliton line boundary, during each ac cycle. In addition to ordinary ‘integer’ steps, coinciding here with the synchronous rigid advancement of the whole colloid monolayer, our main prediction is the existence of additional smaller ‘subharmonic’ steps due to localized solitonic regions of incommensurate layers executing synchronized slips, while the majority of the colloids remains pinned to a potential minimum. The current availability and wide parameter tunability of colloid monolayers makes these predictions potentially easy to access in an experimentally rich 2D geometrical configuration.

  9. Non-abelian gauge fields and topological insulators in shaken optical lattices.

    PubMed

    Hauke, Philipp; Tieleman, Olivier; Celi, Alessio; Olschläger, Christoph; Simonet, Juliette; Struck, Julian; Weinberg, Malte; Windpassinger, Patrick; Sengstock, Klaus; Lewenstein, Maciej; Eckardt, André

    2012-10-05

    Time-periodic driving like lattice shaking offers a low-demanding method to generate artificial gauge fields in optical lattices. We identify the relevant symmetries that have to be broken by the driving function for that purpose and demonstrate the power of this method by making concrete proposals for its application to two-dimensional lattice systems: We show how to tune frustration and how to create and control band touching points like Dirac cones in the shaken kagome lattice. We propose the realization of a topological and a quantum spin Hall insulator in a shaken spin-dependent hexagonal lattice. We describe how strong artificial magnetic fields can be achieved for example in a square lattice by employing superlattice modulation. Finally, exemplified on a shaken spin-dependent square lattice, we develop a method to create strong non-abelian gauge fields.

  10. Open Quantum System Studies of Optical Lattices and Nonlinear Optical Cavities: A Comprehensive Development of Atomtronics

    NASA Astrophysics Data System (ADS)

    Pepino, Ronald A.

    2011-12-01

    A generalized open quantum theory that models the transport properties of bosonic systems is derived from first principles. This theory is shown to correctly describe the long-time behavior of a specific class of non-Markovian system-reservoir interactions. Starting with strongly-interacting bosons in optical lattices, we use this theory to construct a novel, one-to-one analogy with electronic systems, components, and devices. Beginning with the concept of a wire, we demonstrate theoretically the ultracold boson analog of a semiconductor diode, a field-effect transistor, and a bipolar junction transistor. In a manner directly analogous to electronics, we show that it is possible to construct combinatorial logic structures from the fundamental electronic-emulating devices just described. In this sense, our proposal for atomtronic devices is a useful starting point for arrangements with more complex functionality. In addition we show that the behavior of the proposed diode should also be possible utilizing a weakly-interacting, coherent bosonic drive. After demonstrating the formal equivalence between systems comprised of bosons in optical lattices and photons in nonlinear cavity networks, we use the formalism to extend the ideas and concepts developed earlier in ultracold boson systems to nonlinear optical systems. We adapt the open quantum system theory to this new physical environment, and demonstrate theoretically how a few-photon optical diode can be realized in a coupled nonlinear cavity system. An analysis of different practical cavity quantum electrodynamics systems is presented and experimentally-viable candidates are evaluated.

  11. Comparing a mercury optical lattice clock with microwave and optical frequency standards

    NASA Astrophysics Data System (ADS)

    Tyumenev, R.; Favier, M.; Bilicki, S.; Bookjans, E.; Le Targat, R.; Lodewyck, J.; Nicolodi, D.; Le Coq, Y.; Abgrall, M.; Guéna, J.; De Sarlo, L.; Bize, S.

    2016-11-01

    In this paper we report the evaluation of an optical lattice clock based on neutral mercury with a relative uncertainty of 1.7× {10}-16. Comparing this characterized frequency standard to a 133Cs atomic fountain we determine the absolute frequency of the {}1{{{S}}}0\\to {}3{{{P}}}0 transition of 199Hg as {ν }{Hg}=1128 575 290 808 154.62 {Hz}+/- 0.19 {Hz}({statistical})+/- 0.38 {Hz} (systematic), limited solely by the realization of the SI second. Furthermore, by comparing the mercury optical lattice clock to a 87Rb atomic fountain, we determine for the first time to our knowledge the ratio between the 199Hg clock transition and the 87Rb ground state hyperfine transition. Finally we present a direct optical to optical measurement of the 199Hg/87Sr frequency ratio. The obtained value of {ν }{Hg}/{ν }{Sr} = 2.629 314 209 898 909 15 with a fractional uncertainty of 1.8× {10}-16 is in excellent agreement with a similar measurement obtained by Yamanaka et al (2015 Phys. Rev. Lett. 114 230801). This makes this frequency ratio one of the few physical quantities agreed upon by different laboratories to this level of uncertainty. Frequency ratio measurements of the kind reported in this paper have a strong impact for frequency metrology and fundamental physics as they can be used to monitor putative variations of fundamental constants.

  12. Interferometric 30 m bench for calibrations of 1D scales and optical distance measuring instruments

    NASA Astrophysics Data System (ADS)

    Unkuri, J.; Rantanen, A.; Manninen, J.; Esala, V.-P.; Lassila, A.

    2012-09-01

    During construction of a new metrology building for MIKES, a 30 m interferometric bench was designed. The objective was to implement a straight, stable, adjustable and multifunctional 30 m measuring bench for calibrations. Special attention was paid to eliminating the effects of thermal expansion and inevitable concrete shrinkage. The linear guide, situated on top of a monolithic concrete beam, comprises two parallel round shafts with adjustable fixtures every 1 m. A carriage is moved along the rail and its position is followed by a reference interferometer. Depending on the measurement task, one or two retro-reflectors are fixed on the carriage. A microscope with a CCD camera and a monitor can be used to detect line mark positions on different line standards. When calibrating optical distance measuring instruments, various targets can be fixed to the carriage. For the most accurate measurements an online Abbe-error correction based on simultaneous carriage pitch measurement by a separate laser interferometer is applied. The bench is used for calibrations of machinist scales, tapes, circometers, electronic distance meters, total stations and laser trackers. The estimated expanded uncertainty for 30 m displacement for highest accuracy calibrations is 2.6 µm.

  13. A Next-Generation Apparatus for Lithium Optical Lattice Experiments

    NASA Astrophysics Data System (ADS)

    Keshet, Aviv

    Quantum simulation is emerging as an ambitious and active subfield of atomic physics. This thesis describes progress towards the goal of simulating condensed matter systems, in particular the physics of the Fermi-Hubbard model, using ultracold Lithium atoms in an optical lattice. A major goal of the quantum simulation program is to observe phase transitions of the Hubbard model, into Neal antiferromagnetic phases and d-wave superfluid phases. Phase transitions are generally accompanied by a change in an underlying correlation in a physical system. Such correlations may be most amenable to probing by looking at fluctuations in the system. Experimental techniques for probing density and magnetization fluctuations in a variety of atomic Fermi systems are developed. The suppression of density fluctuations (or atom "shot noise") in an ideal degenerate Fermi gas is observed by absorption imaging of time-of-flight expanded clouds. In-trap measurements of density and magnetization fluctuations are not easy to probe with absorption imaging, due to their extremely high attenuation. A method to probe these fluctuations based on speckle patterns, caused by fluctuations in the index of refraction for a detuned illumination beam, is developed and applied first to weakly interacting and then to strongly interacting in-trap gases. Fluctuation probes such as these will be a crucial tool in future quantum simulation of condensed matter systems. The quantum simulation experiments that we want to perform require a complex sequence of precisely timed computer controlled events. A distributed GUI-based control system designed with such experiments in mind, The Cicero Word Generator, is described. The system makes use of a client-server separation between a user interface for sequence design and a set of output hardware servers. Output hardware servers are designed to use standard National Instruments output cards, but the client-server nature allows this to be extended to other output

  14. Exploring the Néel phase using a compensated optical lattice

    NASA Astrophysics Data System (ADS)

    Yang, Tsung-Lin; Coleman, Seth T.; Duarte, Pedro M.; Hart, Russell A.; Hulet, Randall G.

    2015-05-01

    We have realized the Fermi-Hubbard model with fermionic 6Li atoms in a three-dimensional optical lattice. The red-detuned optical lattice is compensated by three additional blue-detuned laser beams which overlap each of the lattice beams, but are not retro-reflected. Using the compensated optical lattice, we have reached temperatures low enough to produce short-range antiferromagnetic (AF) spin correlations, which we detect via Bragg scattering of light. Previously, we reached temperatures down to 1.4 times that of the AFM phase transition, more than a factor of 2 below temperatures obtained previously in 3D optical lattices with fermions. However, the alignment stability of the lattice beams and the lack of tunability of the relative size of the lattice and compensating beam sizes hindered the optimization of the temperature. We have implemented an improved experimental setup which allows us to adjust the lattice beam waist ratios with better long-term stability. We will report on the status of these efforts and our progress on cooling deep into the Néel phase. Work supported by ARO, ONR, NSF and the Welch Foundation.

  15. A LATTICE THEORY OF THE ELECTRO-OPTIC EFFECTS IN SEMICONDUCTORS.

    DTIC Science & Technology

    A unified lattice theory of the electro - optic effect in semiconductor crystals, which encompasses the piezo-electric and elasto-optic effects, is...presented. Expressions are derived for the constant stress and constant strain electro - optic coefficients and the results are specialized to crystals of the zincblende structure. (Author)

  16. Emission difference super-resolution microscopy with optical lattices scanning and wide field detection

    NASA Astrophysics Data System (ADS)

    Zhu, Dazhao; Chen, Youhua; Kuang, Cuifang; Liu, Xu

    2017-07-01

    A parallel scanning method using optical lattices is proposed theoretically to improve the imaging speed of fluorescence emission difference microscopy (FED), which gives the wide field imaging capability to FED while maintaining all the basic advantages of single point FED. The basic principle of wide field FED (wfFED) is presented briefly and the method of generating optical lattices is discussed. The resolution via two types of optical lattices pattern scanning is also studied. With optical lattices scanning, which is generated by two orthogonally crossed standing waves, the wfFED can be implemented without wide field excitation. This strategy can further improve the wfFED imaging speed and simplify the set-up.

  17. Observation of Landau-Zener tunneling through atomic current in the optical lattices

    SciTech Connect

    Yan Jieyun; Duan Suqing; Zhang Wei; Zhao Xiangeng

    2009-05-15

    The atomic current in the Fourier-synthesized optical lattices under a constant external force is investigated theoretically. Based on a two-band model, the atomic current is derived by solving the Boltzmann equations. We find that the stationary atomic current changes with the probability of Landau-Zener tunneling, depending on the adjustable energy structure of the optical lattices. In contrast to the classical results of an electron in superlattices given by the Esaki-Tsu equations, the relation between the stationary atomic current and the strength of the external force in optical lattices is modified significantly. Both these characteristics can be taken as an effective way to observe the Landau-Zener tunneling in the optical lattices.

  18. Synthetic-lattice enabled all-optical devices based on orbital angular momentum of light

    NASA Astrophysics Data System (ADS)

    Luo, Xi-Wang; Zhou, Xingxiang; Xu, Jin-Shi; Li, Chuan-Feng; Guo, Guang-Can; Zhang, Chuanwei; Zhou, Zheng-Wei

    2017-07-01

    All-optical photonic devices are crucial for many important photonic technologies and applications, ranging from optical communication to quantum information processing. Conventional design of all-optical devices is based on photon propagation and interference in real space, which may rely on large numbers of optical elements, and the requirement of precise control makes this approach challenging. Here we propose an unconventional route for engineering all-optical devices using the photon's internal degrees of freedom, which form photonic crystals in such synthetic dimensions for photon propagation and interference. We demonstrate this design concept by showing how important optical devices such as quantum memory and optical filters can be realized using synthetic orbital angular momentum (OAM) lattices in degenerate cavities. The design route utilizing synthetic photonic lattices may significantly reduce the requirement for numerous optical elements and their fine tuning in conventional design, paving the way for realistic all-optical photonic devices with novel functionalities.

  19. Suppression of photothermal convection of microparticles in two dimensional nanoplasmonic optical lattice

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Chung; Yossifon, Gilad; Yang, Ya-Tang

    2016-11-01

    Photothermal convection has been a major obstacle for stable particle trapping in plasmonic optical tweezer at high optical power. Here, we demonstrate a strategy to suppress the plasmonic photothermal convection by using vanishingly small thermal expansion coefficient of water at low temperature. A simple square nanoplasmonic array is illuminated with a loosely Gaussian beam to produce a two dimensional optical lattice for trapping of micro particles. We observe stable particle trapping due to near-field optical gradient forces at elevated optical power at low temperature. In contrast, for the same optical power at room temperature, the particles are convected away from the center of the optical lattice without their accumulation. This technique will greatly increase usable optical power and enhance the trapping capability of plasmonic optical tweezer.

  20. Synthetic-lattice enabled all-optical devices based on orbital angular momentum of light

    PubMed Central

    Luo, Xi-Wang; Zhou, Xingxiang; Xu, Jin-Shi; Li, Chuan-Feng; Guo, Guang-Can; Zhang, Chuanwei; Zhou, Zheng-Wei

    2017-01-01

    All-optical photonic devices are crucial for many important photonic technologies and applications, ranging from optical communication to quantum information processing. Conventional design of all-optical devices is based on photon propagation and interference in real space, which may rely on large numbers of optical elements, and the requirement of precise control makes this approach challenging. Here we propose an unconventional route for engineering all-optical devices using the photon’s internal degrees of freedom, which form photonic crystals in such synthetic dimensions for photon propagation and interference. We demonstrate this design concept by showing how important optical devices such as quantum memory and optical filters can be realized using synthetic orbital angular momentum (OAM) lattices in degenerate cavities. The design route utilizing synthetic photonic lattices may significantly reduce the requirement for numerous optical elements and their fine tuning in conventional design, paving the way for realistic all-optical photonic devices with novel functionalities. PMID:28706215

  1. Synthetic-lattice enabled all-optical devices based on orbital angular momentum of light.

    PubMed

    Luo, Xi-Wang; Zhou, Xingxiang; Xu, Jin-Shi; Li, Chuan-Feng; Guo, Guang-Can; Zhang, Chuanwei; Zhou, Zheng-Wei

    2017-07-14

    All-optical photonic devices are crucial for many important photonic technologies and applications, ranging from optical communication to quantum information processing. Conventional design of all-optical devices is based on photon propagation and interference in real space, which may rely on large numbers of optical elements, and the requirement of precise control makes this approach challenging. Here we propose an unconventional route for engineering all-optical devices using the photon's internal degrees of freedom, which form photonic crystals in such synthetic dimensions for photon propagation and interference. We demonstrate this design concept by showing how important optical devices such as quantum memory and optical filters can be realized using synthetic orbital angular momentum (OAM) lattices in degenerate cavities. The design route utilizing synthetic photonic lattices may significantly reduce the requirement for numerous optical elements and their fine tuning in conventional design, paving the way for realistic all-optical photonic devices with novel functionalities.

  2. Detecting quantum coherence of Bose gases in optical lattices by scattering light intensity in cavity.

    PubMed

    Zhou, Xiaoji; Xu, Xu; Yin, Lan; Liu, W M; Chen, Xuzong

    2010-07-19

    We propose a new method of detecting quantum coherence of a Bose gas trapped in a one-dimensional optical lattice by measuring the light intensity from Raman scattering in cavity. After pump and displacement process, the intensity or amplitude of scattering light is different for different quantum states of a Bose gas, such as superfluid and Mott-Insulator states. This method can also be useful to detect quantum states of atoms with two components in an optical lattice.

  3. Crosstalk comparison of lattice-form optical interleaver with different coupler structures

    NASA Astrophysics Data System (ADS)

    Wan, Zhujun; Luo, Fengguang; Luo, Zhixiang

    2009-05-01

    Lattice circuit made from a cascade of couplers and delay-lines is a popular approach for optical interleaver based on planar lightwave circuit (PLC) technology. Different coupler structures can be employed in the lattice circuit, including 1-stage directional couplers (DCs), 4-stage DCs, and 2-stage multimode interference (MMI) couplers. We fabricated optical interleavers with above three coupler structures, respectively. The experimental results prove that the latter two coupler structures can help to reduce crosstalk, which meets the simulation results well.

  4. Localization and delocalization of ultracold bosonic atoms in finite optical lattices

    SciTech Connect

    Luehmann, Dirk-Soeren; Pfannkuche, Daniela; Bongs, Kai; Sengstock, Klaus

    2008-02-15

    We study bosonic atoms in small optical lattices by exact diagonalization and observe a striking similarity to the superfluid to Mott insulator transition in macroscopic systems. The momentum distribution, the formation of an energy gap, and the pair correlation function show only a weak size dependence. For noncommensurate filling we reveal in deep lattices a mixture of localized and delocalized particles, which is sensitive to lattice imperfections. Breaking the lattice symmetry causes a Bose-glass-like behavior. We discuss the nature of excited states and orbital effects by using an exact diagonalization technique that includes higher bands.

  5. Read-out optical schemes for holographic memory system based on multiplexed computer generated 1D Fourier holograms

    NASA Astrophysics Data System (ADS)

    Donchenko, Sergey S.; Odinokov, Sergey B.; Bobrinev, Vladimir I.; Betin, Alexandr Y.; Zlokazov, Evgenie Y.

    2015-05-01

    Computer holographic synthesis allows to significantly simplify the recording scheme of microholograms in holographic memory system as the classic high precision holographic setup based on two-beam interference is removed by simple scale reduction projection scheme. Application of computer generated 1D-Fourier holograms provides the possibility of selective reconstruction of the multiplexed holograms with different orientation of data lines by corresponding rotation of anamorphic objective (cylindrical lens), used in the read-out systems. Two configurations of read-out optical scheme were investigated by our team: full-page scheme and line-by-line scheme. In the present article we report the specificities of these schemes and consider their advantages and disadvantages. The results of experimental modeling of both read-out configurations are also presented.

  6. Three-dimensional magnetic trap lattice on an atom chip with an optically induced fictitious magnetic field

    SciTech Connect

    Yan Hui

    2010-05-15

    A robust type of three-dimensional magnetic trap lattice on an atom chip combining optically induced fictitious magnetic field with microcurrent-carrying wires is proposed. Compared to the regular optical lattice, the individual trap in this three-dimensional magnetic trap lattice can be easily addressed and manipulated.

  7. Three-dimensional magnetic trap lattice on an atom chip with an optically induced fictitious magnetic field

    NASA Astrophysics Data System (ADS)

    Yan, Hui

    2010-05-01

    A robust type of three-dimensional magnetic trap lattice on an atom chip combining optically induced fictitious magnetic field with microcurrent-carrying wires is proposed. Compared to the regular optical lattice, the individual trap in this three-dimensional magnetic trap lattice can be easily addressed and manipulated.

  8. Phase-Stable Free-Space Optical Lattices for Trapped Ions

    NASA Astrophysics Data System (ADS)

    Schmiegelow, C. T.; Kaufmann, H.; Ruster, T.; Schulz, J.; Kaushal, V.; Hettrich, M.; Schmidt-Kaler, F.; Poschinger, U. G.

    2016-01-01

    We demonstrate control of the absolute phase of an optical lattice with respect to a single trapped ion. The lattice is generated by off-resonant free-space laser beams, and we actively stabilize its phase by measuring its ac-Stark shift on a trapped ion. The ion is localized within the standing wave to better than 2% of its period. The locked lattice allows us to apply displacement operations via resonant optical forces with a controlled direction in phase space. Moreover, we observe the lattice-induced phase evolution of spin superposition states in order to analyze the relevant decoherence mechanisms. Finally, we employ lattice-induced phase shifts for inferring the variation of the ion position over the 157 μ m range along the trap axis at accuracies of better than 6 nm.

  9. Phase-Stable Free-Space Optical Lattices for Trapped Ions.

    PubMed

    Schmiegelow, C T; Kaufmann, H; Ruster, T; Schulz, J; Kaushal, V; Hettrich, M; Schmidt-Kaler, F; Poschinger, U G

    2016-01-22

    We demonstrate control of the absolute phase of an optical lattice with respect to a single trapped ion. The lattice is generated by off-resonant free-space laser beams, and we actively stabilize its phase by measuring its ac-Stark shift on a trapped ion. The ion is localized within the standing wave to better than 2% of its period. The locked lattice allows us to apply displacement operations via resonant optical forces with a controlled direction in phase space. Moreover, we observe the lattice-induced phase evolution of spin superposition states in order to analyze the relevant decoherence mechanisms. Finally, we employ lattice-induced phase shifts for inferring the variation of the ion position over the 157  μm range along the trap axis at accuracies of better than 6 nm.

  10. Vortex formation of a Bose-Einstein condensate in a rotating deep optical lattice

    SciTech Connect

    Kato, Akira; Nakano, Yuki; Kasamatsu, Kenichi; Matsui, Tetsuo

    2011-11-15

    We study the dynamics of vortex nucleation and lattice formation in a Bose-Einstein condensate in a rotating square optical lattice by numerical simulations of the Gross-Pitaevskii equation. Different dynamical regimes of vortex nucleation are found, depending on the depth and period of the optical lattice. We make an extensive comparison with the experiments by R. A. Williams et al.[Phys. Rev. Lett. 104, 050404 (2010)], especially focusing on the issues of the critical rotation frequency for the first vortex nucleation and the vortex number as a function of rotation frequency.

  11. Dynamics of two coupled Bose-Einstein Condensate solitons in an optical lattice.

    PubMed

    Cheng, Yongshan; Gong, Rongzhou; Li, Hong

    2006-04-17

    The characteristics of two coupled Bose-Einstein Condensate (BEC) bright solitons trapped in an optical lattice are investigated with the variational approach and direct numerical simulations of the Gross-Pitaevskii equation. It is found that the optical lattice can be controllably used to capture and drag the coupled BEC solitons. Its effect depends on the initial location of the BEC solitons, the lattice amplitude and wave-number, and the amplitude of the coupled BEC solitons. The effective interaction between the two coupled solitons is the attractive effect.

  12. Creating p-wave superfluids and topological excitations in optical lattices

    SciTech Connect

    Massignan, P.; Sanpera, A.; Lewenstein, M.

    2010-03-15

    We propose to realize a p-wave superfluid using bosons mixed with a single species of fermions in a deep optical lattice. We analyze with a self-consistent method its excitation spectrum in presence of a vortex, and we point out the range of interaction strengths in which the zero-energy mode with topological character exists on a finite optical lattice. Lattice effects are strongest close to fermionic half filling: here the linearity of the low-lying spectrum is lost, and a new class of extended zero-energy modes with checkerboard structure and d-wave symmetry appears.

  13. Construction of ``resonant'' magneto-optical lattices with controlled momentum compaction factor

    NASA Astrophysics Data System (ADS)

    Senichev, Yu. V.; Chechenin, A. N.

    2007-12-01

    On the basis of the theory of “resonant” magneto-optical lattices for synchrotrons with complex transition energy developed in [1], methods for construction of such lattices with application to various accelerators are proposed. Apart from allowing elimination of transition energy crossing by accelerated particles, these lattices should meet a number of important requirements. In particular, they must have dispersion-free straight sections intended for accommodation of RF cavities, Siberian snakes and detectors, and a large enough dynamic aperture for minimizing the effect of magnetic optics nonlinearity on the beam parameters after chromaticity correction by sextupoles.

  14. Construction of 'resonant' magneto-optical lattices with controlled momentum compaction factor

    SciTech Connect

    Senichev, Yu. V. Chechenin, A. N.

    2007-12-15

    On the basis of the theory of 'resonant' magneto-optical lattices for synchrotrons with complex transition energy developed in [1], methods for construction of such lattices with application to various accelerators are proposed. Apart from allowing elimination of transition energy crossing by accelerated particles, these lattices should meet a number of important requirements. In particular, they must have dispersion-free straight sections intended for accommodation of RF cavities, Siberian snakes and detectors, and a large enough dynamic aperture for minimizing the effect of magnetic optics nonlinearity on the beam parameters after chromaticity correction by sextupoles.

  15. Bloch Oscillations in Optical and Zeeman Lattices in the Presence of Spin-Orbit Coupling

    NASA Astrophysics Data System (ADS)

    Kartashov, Yaroslav V.; Konotop, Vladimir V.; Zezyulin, Dmitry A.; Torner, Lluis

    2016-11-01

    We address Bloch oscillations of a spin-orbit coupled atom in periodic potentials of two types: optical and Zeeman lattices. We show that in optical lattices the spin-orbit coupling allows controlling the direction of atomic motion and may lead to complete suppression of the oscillations at specific values of the coupling strength. In Zeeman lattices the energy bands are found to cross each other at the boundaries of the Brillouin zone, resulting in period doubling of the oscillations. In all cases, the oscillations are accompanied by rotation of the pseudospin, with a dynamics that is determined by the strength of the spin-orbit coupling. The predicted effects are discussed also in terms of a Wannier-Stark ladder, which in optical lattices consist of two mutually shifted equidistant subladders.

  16. Lattice design of the integrable optics test accelerator and optical stochastic cooling experiment at Fermilab

    SciTech Connect

    Kafka, Gene

    2015-05-01

    The Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab will serve as the backbone for a broad spectrum of Advanced Accelerator R&D (AARD) experiments, and as such, must be designed with signi cant exibility in mind, but without compromising cost e ciency. The nonlinear experiments at IOTA will include: achievement of a large nonlinear tune shift/spread without degradation of dynamic aperture; suppression of strong lattice resonances; study of stability of nonlinear systems to perturbations; and studies of di erent variants of nonlinear magnet design. The ring optics control has challenging requirements that reach or exceed the present state of the art. The development of a complete self-consistent design of the IOTA ring optics, meeting the demands of all planned AARD experiments, is presented. Of particular interest are the precise control for nonlinear integrable optics experiments and the transverse-to-longitudinal coupling and phase stability for the Optical Stochastic Cooling Experiment (OSC). Since the beam time-of- ight must be tightly controlled in the OSC section, studies of second order corrections in this section are presented.

  17. Compact 1D-silicon photonic crystal electro-optic modulator operating with ultra-low switching voltage and energy.

    PubMed

    Shakoor, Abdul; Nozaki, Kengo; Kuramochi, Eiichi; Nishiguchi, Katsuhiko; Shinya, Akihiko; Notomi, Masaya

    2014-11-17

    We demonstrate a small foot print (600 nm wide) 1D silicon photonic crystal electro-optic modulator operating with only a 50 mV swing voltage and 0.1 fJ/bit switching energy at GHz speeds, which are the lowest values ever reported for a silicon electro-optic modulator. A 3 dB extinction ratio is demonstrated with an ultra-low 50 mV swing voltage with a total device energy consumption of 42.8 fJ/bit, which is dominated by the state holding energy. The total energy consumption is reduced to 14.65 fJ/bit for a 300 mV swing voltage while still keeping the switching energy at less than 2 fJ/bit. Under optimum voltage conditions, the device operates with a maximum speed of 3 Gbps with 8 dB extinction ratio, which rises to 11 dB for a 1 Gbps modulation speed.

  18. 1-D, 2-D and 3-D Negative-Refraction Metamaterials at Optical Frequencies: Optical Nano-Transmission-Line and Circuit Theory

    NASA Astrophysics Data System (ADS)

    Engheta, Nader; Alu, Andrea

    2006-03-01

    In recent years metamaterials have offered new possibilities for overcoming some of the intrinsic limitations in wave propagation. Their realization at microwave frequencies has followed two different paths; one consisting of embedding resonant inclusions in a host dielectric, and the other following a transmission-line approach, i.e., building 1-D, 2-D, or 3-D cascades of circuit elements, respectively, as linear, planar or bulk right- or left-handed metamaterials. The latter is known to provide larger bandwidth and better robustness to ohmic losses. Extending these concepts to optical frequencies is a challenging task, due to changes in material response to electromagnetic waves at these frequencies. However, recently we have studied theoretically how it may be possible to have circuit nano-elements at these frequencies by properly exploiting plasmonic resonances. Here we present our theoretical work on translating the circuit concepts of right- and left-handed metamaterials into optical frequencies by applying the analogy between nanoparticles and nanocircuit elements in transmission lines. We discuss how it is possible to synthesize optical negative-refraction metamaterials by properly cascading plasmonic and non-plasmonic elements in 1-D, 2-D and 3-D geometries.

  19. Deriving eigenmode excitation spectrum of synthetic photonic lattices by means of optical heterodyning

    NASA Astrophysics Data System (ADS)

    Tikan, A. M.; Vatnik, I. D.; Churkin, D. V.; Sukhorukov, A. A.

    2017-02-01

    A method based on optical heterodyning is proposed for measuring relative optical phases of pulses circulating in synthetic photonic lattices (SPL). The knowledge of the phases can be further used for qualitative reconstruction of an eigenmode excitation spectrum in the SPL.

  20. Trapping of Neutral Mercury Atoms and Prospects for Optical Lattice Clocks

    SciTech Connect

    Hachisu, H.; Takamoto, M.; Katori, H.; Miyagishi, K.; Porsev, S. G.; Derevianko, A.; Ovsiannikov, V. D.; Pal'chikov, V. G.

    2008-02-08

    We report vapor-cell magneto-optical trapping of Hg isotopes on the {sup 1}S{sub 0}-{sup 3}P{sub 1} intercombination transition. Six abundant isotopes, including four bosons and two fermions, were trapped. Hg is the heaviest nonradioactive atom trapped so far, which enables sensitive atomic searches for ''new physics'' beyond the standard model. We propose an accurate optical lattice clock based on Hg and evaluate its systematic accuracy to be better than 10{sup -18}. Highly accurate and stable Hg-based clocks will provide a new avenue for the research of optical lattice clocks and the time variation of the fine-structure constant.

  1. Trapping of neutral mercury atoms and prospects for optical lattice clocks.

    PubMed

    Hachisu, H; Miyagishi, K; Porsev, S G; Derevianko, A; Ovsiannikov, V D; Pal'chikov, V G; Takamoto, M; Katori, H

    2008-02-08

    We report vapor-cell magneto-optical trapping of Hg isotopes on the (1)S(0)-(3)P(1) intercombination transition. Six abundant isotopes, including four bosons and two fermions, were trapped. Hg is the heaviest nonradioactive atom trapped so far, which enables sensitive atomic searches for "new physics" beyond the standard model. We propose an accurate optical lattice clock based on Hg and evaluate its systematic accuracy to be better than 10;{-18}. Highly accurate and stable Hg-based clocks will provide a new avenue for the research of optical lattice clocks and the time variation of the fine-structure constant.

  2. Controlling dipole-dipole frequency shifts in a lattice-based optical atomic clock

    SciTech Connect

    Chang, D.E.; Lukin, M.D.; Ye Jun

    2004-02-01

    Motivated by the ideas of using cold alkaline-earth atoms trapped in an optical lattice for realization of optical atomic clocks, we investigate theoretically the perturbative effects of atom-atom interactions on a clock transition frequency. These interactions are mediated by the dipole fields associated with the optically excited atoms. We predict resonancelike features in the frequency shifts when constructive interference among atomic dipoles occur. We theoretically demonstrate that by fine tuning the coherent dipole-dipole couplings in appropriately designed lattice geometries, the undesirable frequency shifts can be greatly suppressed.

  3. Frequency-doubled telecom fiber laser for a cold atom interferometer using optical lattices

    NASA Astrophysics Data System (ADS)

    Theron, Fabien; Bidel, Yannick; Dieu, Emily; Zahzam, Nassim; Cadoret, Malo; Bresson, Alexandre

    2017-06-01

    A compact and robust frequency-doubled telecom laser system at 780 nm is presented for a rubidium cold atom interferometer using optical lattices. Adopting an optical switch at 1.5 μm and a dual-wavelength second harmonic generation system, only one laser amplifier is required for the laser system. Our system delivers a 900 mW laser beam with a detuning of 110 GHz for the optical lattice and a 650 mW laser beam with an adjustable detuning between 0 and -1 GHz for the laser cooling, the detection and the Raman transitions.

  4. 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.

  5. Cooling and long-lived single-site localization of an ion in an optical lattice

    NASA Astrophysics Data System (ADS)

    Bylinskii, Alexei; Karpa, Leon; Gangloff, Dorian; Cetina, Marko; Vuletic, Vladan

    2013-05-01

    We report on localization of a continuously cooled single ion by a one-dimensional optical lattice. The ion is confined in a hybrid trap formed by an optical dipole potential produced by the standing-wave field of an optical cavity and a two-dimensional radio-frequency Paul trap transverse to the cavity axis. A lattice-assisted resolved Raman sideband process cools the ion to energies 20 times lower than the depth of the lattice potential, close to the vibrational ground state. We observe ion localization by measuring its displacement in the presence of a periodically driven electric field parallel to the lattice. We demonstrate full suppression of the driven ion motion due to optical localization to a single lattice site on a time-scale of 100 μs, which is 100 times longer than the vibrational period of the ion in the lattice site. At a longer time scale of 1 ms, driven motion is suppressed to 50%. The presented system paves the way to the realization of novel experiments studying classical and quantum friction models, and many-body physics with long-range interactions in periodic potentials. Army Research Office, National Science Foundation, National Science and Engineering Research Council of Canada, Alexander von Humboldt Foundation.

  6. Matter-wave two-dimensional solitons in crossed linear and nonlinear optical lattices

    SciTech Connect

    Luz, H. L. F. da; Gammal, A.; Abdullaev, F. Kh.; Salerno, M.; Tomio, Lauro

    2010-10-15

    The existence of multidimensional matter-wave solitons in a crossed optical lattice (OL) with a linear optical lattice (LOL) in the x direction and a nonlinear optical lattice (NOL) in the y direction, where the NOL can be generated by a periodic spatial modulation of the scattering length using an optically induced Feshbach resonance is demonstrated. In particular, we show that such crossed LOLs and NOLs allow for stabilizing two-dimensional solitons against decay or collapse for both attractive and repulsive interactions. The solutions for the soliton stability are investigated analytically, by using a multi-Gaussian variational approach, with the Vakhitov-Kolokolov necessary criterion for stability; and numerically, by using the relaxation method and direct numerical time integrations of the Gross-Pitaevskii equation. Very good agreement of the results corresponding to both treatments is observed.

  7. Matter-wave two-dimensional solitons in crossed linear and nonlinear optical lattices

    NASA Astrophysics Data System (ADS)

    da Luz, H. L. F.; Abdullaev, F. Kh.; Gammal, A.; Salerno, M.; Tomio, Lauro

    2010-10-01

    The existence of multidimensional matter-wave solitons in a crossed optical lattice (OL) with a linear optical lattice (LOL) in the x direction and a nonlinear optical lattice (NOL) in the y direction, where the NOL can be generated by a periodic spatial modulation of the scattering length using an optically induced Feshbach resonance is demonstrated. In particular, we show that such crossed LOLs and NOLs allow for stabilizing two-dimensional solitons against decay or collapse for both attractive and repulsive interactions. The solutions for the soliton stability are investigated analytically, by using a multi-Gaussian variational approach, with the Vakhitov-Kolokolov necessary criterion for stability; and numerically, by using the relaxation method and direct numerical time integrations of the Gross-Pitaevskii equation. Very good agreement of the results corresponding to both treatments is observed.

  8. Normal Mode Splitting and Mechanical Effects of an Optical Lattice in a Ring Cavity

    NASA Astrophysics Data System (ADS)

    Klinner, Julian; Lindholdt, Malik; Nagorny, Boris; Hemmerich, Andreas

    2006-01-01

    A novel regime of atom-cavity physics is explored, arising when large atom samples dispersively interact with high-finesse optical cavities. A stable far-detuned optical lattice of several million rubidium atoms is formed inside an optical ring resonator by coupling equal amounts of laser light to each propagation direction of a longitudinal cavity mode. An adjacent longitudinal mode, detuned by about 3 GHz, is used to perform probe transmission spectroscopy of the system. The atom-cavity coupling for the lattice beams and the probe is dispersive and dissipation results only from the finite photon-storage time. The observation of two well-resolved normal modes demonstrates the regime of strong cooperative coupling. The details of the normal mode spectrum reveal mechanical effects associated with the retroaction of the probe upon the optical lattice.

  9. Normal mode splitting and mechanical effects of an optical lattice in a ring cavity.

    PubMed

    Klinner, Julian; Lindholdt, Malik; Nagorny, Boris; Hemmerich, Andreas

    2006-01-20

    A novel regime of atom-cavity physics is explored, arising when large atom samples dispersively interact with high-finesse optical cavities. A stable far-detuned optical lattice of several million rubidium atoms is formed inside an optical ring resonator by coupling equal amounts of laser light to each propagation direction of a longitudinal cavity mode. An adjacent longitudinal mode, detuned by about 3 GHz, is used to perform probe transmission spectroscopy of the system. The atom-cavity coupling for the lattice beams and the probe is dispersive and dissipation results only from the finite photon-storage time. The observation of two well-resolved normal modes demonstrates the regime of strong cooperative coupling. The details of the normal mode spectrum reveal mechanical effects associated with the retroaction of the probe upon the optical lattice.

  10. p-Wave Cold Collisions in an Optical Lattice Clock

    SciTech Connect

    Lemke, N. D.; Sherman, J. A.; Oates, C. W.; Ludlow, A. D.; Stecher, J. von; Rey, A. M.

    2011-09-02

    We study ultracold collisions in fermionic ytterbium by precisely measuring the energy shifts they impart on the atoms' internal clock states. Exploiting Fermi statistics, we uncover p-wave collisions, in both weakly and strongly interacting regimes. With the higher density afforded by two-dimensional lattice confinement, we demonstrate that strong interactions can lead to a novel suppression of this collision shift. In addition to reducing the systematic errors of lattice clocks, this work has application to quantum information and quantum simulation with alkaline-earth atoms.

  11. Interaction-induced excited-band condensate in a double-well optical lattice

    SciTech Connect

    Zhou Qi; Das Sarma, S.; Porto, J. V.

    2011-09-15

    We show theoretically that interaction effects in a double-well optical lattice can induce condensates in an excited band. For a symmetric double-well lattice, bosons condense into the bottom of the excited band at the edge of the Brillouin zone if the chemical potential is above a critical value. For an asymmetric lattice, a condensate with zero momentum is automatically induced in the excited band by the condensate in the lowest band. This is due to a combined effect of interaction and lattice potential, which reduces the band gap and breaks the inversion symmetry. Our work can be generalized to a superlattice composed of multiple-well potentials at each lattice site, where condensates can be induced in even higher bands.

  12. Ultracold nonreactive molecules in an optical lattice: connecting chemistry to many-body physics

    NASA Astrophysics Data System (ADS)

    Mukherjee, Rick; Ewart, Kevin; Alam, Shah; Wall, Michael; Doçaj, Andris; Hazzard, Kaden

    2016-05-01

    We derive effective lattice models for ultracold bosonic or fermionic nonreactive molecules (NRMs) in an optical lattice. In stark contrast to the standard Hubbard model, which is commonly assumed to accurately describe NRMs, we find that the single on-site interaction parameter U is replaced by a multi-channel interaction. The complex, multi-channel collisional physics is unrelated to dipolar interactions, and so occurs even in the absence of an electric field or for homonuclear molecules. We find a crossover between coherent few-channel models and fully incoherent single-channel models as the lattice depth is increased. We devise ways to control the effective model parameters using external fields and lattice anisotropy. We show that these parameters can be determined in lattice modulation experiments, which measure molecular collision dynamics with a vastly sharper energy resolution than experiments in an ultracold gas. We will report our progress calculating this novel model's ground state phase diagram.

  13. Ultracold Nonreactive Molecules in an Optical Lattice: Connecting Chemistry to Many-Body Physics.

    PubMed

    Doçaj, Andris; Wall, Michael L; Mukherjee, Rick; Hazzard, Kaden R A

    2016-04-01

    We derive effective lattice models for ultracold bosonic or fermionic nonreactive molecules (NRMs) in an optical lattice, analogous to the Hubbard model that describes ultracold atoms in a lattice. In stark contrast to the Hubbard model, which is commonly assumed to accurately describe NRMs, we find that the single on-site interaction parameter U is replaced by a multichannel interaction, whose properties we elucidate. Because this arises from complex short-range collisional physics, it requires no dipolar interactions and thus occurs even in the absence of an electric field or for homonuclear molecules. We find a crossover between coherent few-channel models and fully incoherent single-channel models as the lattice depth is increased. We show that the effective model parameters can be determined in lattice modulation experiments, which, consequently, measure molecular collision dynamics with a vastly sharper energy resolution than experiments in a free-space ultracold gas.

  14. Weyl points in three-dimensional optical lattices: synthetic magnetic monopoles in momentum space

    NASA Astrophysics Data System (ADS)

    Buljan, Hrvoje; Dubcek, Tena; Kennedy, Colin; Lu, Ling; Ketterle, Wolfgang; Soljacic, Marin

    2015-05-01

    We show that Hamiltonians with Weyl points can be realized for ultracold atoms using laser-assisted tunneling in three-dimensional (3D) optical lattices. Weyl points are synthetic magnetic monopoles that exhibit a robust, 3D linear dispersion (e.g., see). They are associated with many interesting topological states of matter, such as Weyl semimetals and chiral Weyl fermions. However, Weyl points have yet to be experimentally observed in any system. We show that this elusive goal is well-within experimental reach with an extension of the techniques recently used to obtain the Harper Hamiltonian. We propose using laser assisted tunneling to create a 3D optical lattice, with specifically designed hopping between lattice sites that breaks inversion symmetry. The design leads to creation of four Weyl points in the Brillouin zone of the lattice, which are verified to be monopoles of the synthetic magnetic field. Supported by the Unity through Knowledge Fund (Grant 5/13).

  15. Simulating Dirac fermions with Abelian and non-Abelian gauge fields in optical lattices

    SciTech Connect

    Alba, E.; Fernandez-Gonzalvo, X.; Mur-Petit, J.; Garcia-Ripoll, J.J.; Pachos, J.K.

    2013-01-15

    In this work we present an optical lattice setup to realize a full Dirac Hamiltonian in 2+1 dimensions. We show how all possible external potentials coupled to the Dirac field can arise from perturbations of the existing couplings of the honeycomb lattice pattern. This greatly simplifies the proposed implementations, requiring only spatial modulations of the intensity of the laser beams to induce complex non-Abelian potentials. We finally suggest several experiments to observe the properties of the quantum field theory in the setup. - Highlights: Black-Right-Pointing-Pointer This work provides a very flexible setup for simulating Dirac fermions. Black-Right-Pointing-Pointer The manuscript contains a detailed study of optical lattice deformations. Black-Right-Pointing-Pointer The link between lattice deformations and effective gauge Hamiltonians is studied.

  16. Topological phases and edge states in a non-Hermitian trimerized optical lattice

    NASA Astrophysics Data System (ADS)

    Jin, L.

    2017-09-01

    Topologically engineered optical materials support robust light transport. Herein, the investigated non-Hermitian lattice is trimerized and inhomogeneously coupled using uniform intracell coupling. The topological properties of the coupled waveguide lattice are evaluated and we find that the PT -symmetric phase of a PT -symmetric lattice can have different topologies; the edge states depend on the lattice size, boundary configuration, and competition between the coupling and degree of non-Hermiticity. The topologically nontrivial region is extended in the presence of periodic gain and loss. The nonzero geometric phases accumulated by the Bloch bands indicate the existence of topologically protected edge states between the band gaps. The unidirectional amplification and attenuation zero modes appear above a threshold degree of non-Hermiticity, which facilitates the development of a robust optical diode.

  17. Floquet Realization and Signatures of One-Dimensional Anyons in an Optical Lattice

    NASA Astrophysics Data System (ADS)

    Sträter, Christoph; Srivastava, Shashi C. L.; Eckardt, André

    2016-11-01

    We propose a simple scheme for mimicking the physics of one-dimensional anyons in an optical-lattice experiment. It relies on a bosonic representation of the anyonic Hubbard model to be realized via lattice-shaking-induced resonant tunneling against potential offsets, which are created by a combination of a lattice tilt and strong on-site interactions. No lasers additional to those used for the creation of the optical lattice are required. We also discuss experimental signatures of the continuous interpolation between bosons and fermions when the statistical angle θ is varied from 0 to π . Whereas the real-space density of the bosonic atoms corresponds directly to that of the simulated anyonic model, this is not the case for the momentum distribution. Therefore, we propose to use Friedel oscillations in the density as a probe for continuous fermionization of the bosonic atoms.

  18. Resolved Sideband Spectroscopy and Cooling of Strontium in a 532-nm Optical Lattice

    NASA Astrophysics Data System (ADS)

    Aman, James; Hill, Joshua; Killian, T. C.

    2016-05-01

    Resolved sideband cooling is a powerful and well established technique for driving ultracold atoms in optical lattices to the motional ground state of individual lattice sites. Here we present spectroscopy of the narrow 5s21S0 --> 5 s 5 p3P1 transition for neutral strontium-84 in a 532nm optical lattice. Resolved red- and blue-detuned sidebands are observed corresponding to changes in the motional state in the lattice sites. Driving the red sideband, we demonstrate cooling into the ground state, which increases the initial phase-space density before forced evaporative cooling. This is a promising technique for improving the production of strontium quantum degenerate gases. Research supported by the Robert A, Welch Foundation under Grant No. C-1844.

  19. Quantum phases of the extended Bose-Hubbard hamiltonian: possibility of a supersolid state of cold atoms in optical lattices.

    PubMed

    Scarola, V W; Das Sarma, S

    2005-07-15

    Cold atom optical lattices typically simulate zero-range Hubbard models. We discuss the theoretical possibility of using excited states of optical lattices to generate extended range Hubbard models. We find that bosons confined to higher bands of optical lattices allow for a rich phase diagram, including the supersolid phase. Using Gutzwiller, mean-field theory we establish the parameter regime necessary to maintain metastable states generated by an extended Bose-Hubbard model.

  20. Hall effects in Bose-Einstein condensates in a rotating optical lattice

    SciTech Connect

    Bhat, Rajiv; Kraemer, M.; Cooper, J.; Holland, M. J.

    2007-10-15

    Using linear response theory, we demonstrate fractional quantum Hall features in a rotating Bose-Einstein condensate in a corotating two-dimensional optical lattice. The corotating lattice and trap potential allow for an effective magnetic field and compensation of the centrifugal potential. Fractional quantum Hall features in the current response are seen for the single-particle system and for a few strongly interacting many-particle systems.

  1. Driving Defect Modes of Bose-Einstein Condensates in Optical Lattices

    SciTech Connect

    Brazhnyi, Valeriy A.; Konotop, Vladimir V.; Perez-Garcia, Victor M.

    2006-02-17

    We present an approximate analytical theory and direct numerical computation of defect modes of a Bose-Einstein condensate loaded in an optical lattice and subject to an additional localized (defect) potential. Some of the modes are found to be remarkably stable and can be driven along the lattice by means of a defect moving following a steplike function defined by the period of Josephson oscillations and the macroscopic stability of the atoms.

  2. Spin-Orbit-Coupled Bose-Einstein Condensates in a One-Dimensional Optical Lattice

    NASA Astrophysics Data System (ADS)

    Hamner, C.; Zhang, Yongping; Khamehchi, M. A.; Davis, Matthew J.; Engels, P.

    2015-02-01

    We investigate a spin-orbit-coupled Bose-Einstein condensate loaded into a translating optical lattice. We experimentally demonstrate the lack of Galilean invariance in the spin-orbit-coupled system, which leads to anisotropic behavior of the condensate depending on the direction of translation of the lattice. The anisotropy is theoretically understood by an effective dispersion relation. We experimentally confirm this theoretical picture by probing the dynamical instability of the system.

  3. Ground states of a Bose-Einstein Condensate in a one-dimensional laser-assisted optical lattice

    NASA Astrophysics Data System (ADS)

    Sun, Qing; Hu, Jie; Wen, Lin; Liu, W.-M.; Juzeliūnas, G.; Ji, An-Chun

    2016-11-01

    We study the ground-state behavior of a Bose-Einstein Condensate (BEC) in a Raman-laser-assisted one-dimensional (1D) optical lattice potential forming a multilayer system. We find that, such system can be described by an effective model with spin-orbit coupling (SOC) of pseudospin (N-1)/2, where N is the number of layers. Due to the intricate interplay between atomic interactions, SOC and laser-assisted tunnelings, the ground-state phase diagrams generally consist of three phases-a stripe, a plane wave and a normal phase with zero-momentum, touching at a quantum tricritical point. More important, even though the single-particle states only minimize at zero-momentum for odd N, the many-body ground states may still develop finite momenta. The underlying mechanisms are elucidated. Our results provide an alternative way to realize an effective spin-orbit coupling of Bose gas with the Raman-laser-assisted optical lattice, and would also be beneficial to the studies on SOC effects in spinor Bose systems with large spin.

  4. Ground states of a Bose-Einstein Condensate in a one-dimensional laser-assisted optical lattice

    PubMed Central

    Sun, Qing; Hu, Jie; Wen, Lin; Liu, W.-M.; Juzeliūnas, G.; Ji, An-Chun

    2016-01-01

    We study the ground-state behavior of a Bose-Einstein Condensate (BEC) in a Raman-laser-assisted one-dimensional (1D) optical lattice potential forming a multilayer system. We find that, such system can be described by an effective model with spin-orbit coupling (SOC) of pseudospin (N-1)/2, where N is the number of layers. Due to the intricate interplay between atomic interactions, SOC and laser-assisted tunnelings, the ground-state phase diagrams generally consist of three phases–a stripe, a plane wave and a normal phase with zero-momentum, touching at a quantum tricritical point. More important, even though the single-particle states only minimize at zero-momentum for odd N, the many-body ground states may still develop finite momenta. The underlying mechanisms are elucidated. Our results provide an alternative way to realize an effective spin-orbit coupling of Bose gas with the Raman-laser-assisted optical lattice, and would also be beneficial to the studies on SOC effects in spinor Bose systems with large spin. PMID:27883037

  5. Roton-maxon excitation spectrum of Bose condensates in a shaken optical lattice.

    PubMed

    Ha, Li-Chung; Clark, Logan W; Parker, Colin V; Anderson, Brandon M; Chin, Cheng

    2015-02-06

    We present experimental evidence showing that an interacting Bose condensate in a shaken optical lattice develops a roton-maxon excitation spectrum, a feature normally associated with superfluid helium. The roton-maxon feature originates from the double-well dispersion in the shaken lattice, and can be controlled by both the atomic interaction and the lattice modulation amplitude. We determine the excitation spectrum using Bragg spectroscopy and measure the critical velocity by dragging a weak speckle potential through the condensate-both techniques are based on a digital micromirror device. Our dispersion measurements are in good agreement with a modified Bogoliubov model.

  6. Dynamics of a Bose-Einstein condensate in a horizontally vibrating shallow optical lattice

    SciTech Connect

    Valizadeh, A.; Jahanbani, Kh.; Kolahchi, M. R.

    2010-02-15

    We consider a solitonic solution of the self-attractive Bose-Einstein condensate in a one-dimensional external potential of a shallow optical lattice with large periodicity when the lattice is horizontally shaken. We investigate the dynamics of the bright soliton through the properties of the fixed points. The special type of bifurcation results in a simple criterion for the stability of the fixed points depending only on the amplitude of the shaking lattice. Because of the similarity of the equations with those of an ac-driven Josephson junction, some results may find applications in other branches of physics.

  7. Dynamics of a Bose-Einstein condensate in a horizontally vibrating shallow optical lattice

    NASA Astrophysics Data System (ADS)

    Valizadeh, A.; Jahanbani, Kh.; Kolahchi, M. R.

    2010-02-01

    We consider a solitonic solution of the self-attractive Bose-Einstein condensate in a one-dimensional external potential of a shallow optical lattice with large periodicity when the lattice is horizontally shaken. We investigate the dynamics of the bright soliton through the properties of the fixed points. The special type of bifurcation results in a simple criterion for the stability of the fixed points depending only on the amplitude of the shaking lattice. Because of the similarity of the equations with those of an ac-driven Josephson junction, some results may find applications in other branches of physics.

  8. Effect of atomic flux reversal in a fluctuating moving optical lattice

    NASA Astrophysics Data System (ADS)

    Makarov, D. V.

    2017-06-01

    The dynamics of an ensemble of noninteracting cold atoms is considered in the field of a moving optical lattice subjected to random amplitude and phase fluctuations. The effect of the reversal of an atomic ensemble under the action of lattice fluctuations is demonstrated, in which the atoms begin to move in the direction opposite to that of the lattice motion. A kinetic model is constructed that reproduces this effect and makes it possible to relate its emergence to the asymmetry of the amplitudes of the interlevel transitions in a momentum space.

  9. Solids and Supersolids of Three-Body Interacting Polar Molecules on an Optical Lattice

    SciTech Connect

    Schmidt, Kai P.; Dorier, Julien; Laeuchli, Andreas M.

    2008-10-10

    We study the physics of cold polar molecules loaded into an optical lattice in the regime of strong three-body interactions, as put forward recently by Buechler et al.[Nature Phys. 3, 726 (2007)]. To this end, quantum Monte Carlo simulations, exact diagonalization, and a semiclassical approach are used to explore hard-core bosons on the 2D square lattice which interact solely by long-ranged three-body terms. The resulting phase diagram shows a sequence of solid and supersolid phases. Our findings are directly relevant for future experimental implementations and open a new route towards the discovery of a lattice supersolid phase in experiment.

  10. Vortex Formation of Rotating Bose-Einstein Condensates in Synthetic Magnetic Field with Optical Lattice

    NASA Astrophysics Data System (ADS)

    Zhao, Qiang

    2016-02-01

    Motivated by recent experiments carried out by Spielman's group at NIST, we study the vortex formation in a rotating Bose-Einstein condensate in synthetic magnetic field confined in a harmonic potential combined with an optical lattice. We obtain numerical solutions of the two-dimensional Gross-Pitaevskii equation and compare the vortex formation by synthetic magnetic field method with those by rotating frame method. We conclude that a large angular momentum indeed can be created in the presence of the optical lattice. However, it is still more difficult to rotate the condensate by the synthetic magnetic field than by the rotating frame even if the optical lattice is added, and the chemical potential and energy remain almost unchanged by increasing rotational frequency.

  11. Fermionization and Mott-insulator formation in fermion trimers loaded in one-dimensional optical lattices

    NASA Astrophysics Data System (ADS)

    Gordillo, M. C.; De Soto, F.

    2017-07-01

    The behavior of small clusters of one spin-up and two spin-down fermions with unlike-spin repulsive interactions in one-dimensional optical lattices was calculated using a diffusion Monte Carlo technique. We considered also a harmonic potential in the longitudinal direction to make our system resemble the standard experimental setups. When the interparticle repulsion is strong enough, the onset of fermionization is observed irrespective of the optical lattice parameters considered, in line with previous results for pure harmonic confinement. However, fermionization can also be seen even for small interparticle couplings if the optical potential is deep enough. In addition, for certain values of the wavelengths and the potential depths defining the lattice, Mott insulators in the fermionization limit with only three atoms were found.

  12. A quantum gas of polar KRb molecules in an optical lattice

    NASA Astrophysics Data System (ADS)

    Covey, Jacob; Miecnikowski, Matthew; Moses, Steven; Fu, Zhengkun; Jin, Deborah; Ye, Jun

    2016-05-01

    Ultracold polar molecules provide new opportunities for investigation of strongly correlated many-body spin systems such as many-body localization and quantum magnetism. In an effort to access such phenomena, we load polar KRb molecules into a three-dimensional optical lattice. In this system, we observed many-body spin dynamics between molecules pinned in a deep lattice, even though the filling fraction of the molecules was only 5%. We have recently performed a thorough investigation of the molecule creation process in an optical lattice, and consequently improved our filling fraction to 30% by preparing and overlapping Mott and band insulators of the initial atomic gases. More recently, we switched to a second generation KRb apparatus that will allow application of large, stable electric fields as well as high-resolution addressing and detection of polar molecules in optical lattices. We plan to use these capabilities to study non-equilibrium spin dynamics in an optical lattice with nearly single site resolution. I will present the status and direction of the second generation apparatus.

  13. Low-Entropy States of Neutral Atoms in Polarization-Synthesized Optical Lattices

    NASA Astrophysics Data System (ADS)

    Robens, Carsten; Zopes, Jonathan; Alt, Wolfgang; Brakhane, Stefan; Meschede, Dieter; Alberti, Andrea

    2017-02-01

    We create low-entropy states of neutral atoms by utilizing a conceptually new optical-lattice technique that relies on a high-precision, high-bandwidth synthesis of light polarization. Polarization-synthesized optical lattices provide two fully controllable optical lattice potentials, each of them confining only atoms in either one of the two long-lived hyperfine states. By employing one lattice as the storage register and the other one as the shift register, we provide a proof of concept using four atoms that selected regions of the periodic potential can be filled with one particle per site. We expect that our results can be scaled up to thousands of atoms by employing an atom-sorting algorithm with logarithmic complexity, which is enabled by polarization-synthesized optical lattices. Vibrational entropy is subsequently removed by sideband cooling methods. Our results pave the way for a bottom-up approach to creating ultralow-entropy states of a many-body system.

  14. Low-Entropy States of Neutral Atoms in Polarization-Synthesized Optical Lattices.

    PubMed

    Robens, Carsten; Zopes, Jonathan; Alt, Wolfgang; Brakhane, Stefan; Meschede, Dieter; Alberti, Andrea

    2017-02-10

    We create low-entropy states of neutral atoms by utilizing a conceptually new optical-lattice technique that relies on a high-precision, high-bandwidth synthesis of light polarization. Polarization-synthesized optical lattices provide two fully controllable optical lattice potentials, each of them confining only atoms in either one of the two long-lived hyperfine states. By employing one lattice as the storage register and the other one as the shift register, we provide a proof of concept using four atoms that selected regions of the periodic potential can be filled with one particle per site. We expect that our results can be scaled up to thousands of atoms by employing an atom-sorting algorithm with logarithmic complexity, which is enabled by polarization-synthesized optical lattices. Vibrational entropy is subsequently removed by sideband cooling methods. Our results pave the way for a bottom-up approach to creating ultralow-entropy states of a many-body system.

  15. Detection of antiferromagnetic order by cooling atoms in an optical lattice

    NASA Astrophysics Data System (ADS)

    Yang, Tsung-Lin; Teles, Rafael; Hazzard, Kaden; Hulet, Randall; Rice University Collaboration

    2016-05-01

    We have realized the Fermi-Hubbard model with fermionic 6 Li atoms in a three-dimensional compensated optical lattice. The compensated optical lattice has provided low enough temperatures to produce short-range antiferromagnetic (AF) spin correlations, which we detect via Bragg scattering of light. Previously, we reached temperatures down to 1.4 times that of the AFM phase transition, more than a factor of 2 below temperatures obtained previously in 3D optical lattices with fermions. In order to further reduce the entropy in the compensated lattice, we implement an entropy conduit - which is a single blue detuned laser beam with a waist size smaller than the overall atomic sample size. This repulsive narrow potential provides a conductive metallic path between the low entropy core and the edges of the atomic sample where atoms may be evaporated. In addition, the entropy conduit may store entropy, thus further lowering the entropy in the core. We will report on the status of these efforts to further cool atoms in the optical lattice. Work supported by ARO MURI Grant, NSF and The Welch Foundation.

  16. Two-dimensional defect modes in optically induced photonic lattices

    SciTech Connect

    Wang Jiandong; Yang Jianke; Chen Zhigang

    2007-07-15

    In this article, localized linear defect modes due to band gap guidance in two-dimensional photonic lattices with localized or nonlocalized defects are investigated theoretically. First, when the defect is localized and weak, eigenvalues of defect modes bifurcated from edges of Bloch bands are derived analytically. It is shown that in an attractive (repulsive) defect, defect modes bifurcate out from Bloch-band edges with normal (anomalous) diffraction coefficients. Furthermore, distances between defect-mode eigenvalues and Bloch-band edges decrease exponentially with the defect strength, which is very different from the one-dimensional case where such distances decrease quadratically with the defect strength. It is also found that some defect-mode branches bifurcate not from Bloch-band edges, but from quasiedge points within Bloch bands, which is very unusual. Second, when the defect is localized but strong, defect modes are determined numerically. It is shown that both the repulsive and attractive defects can support various types of defect modes such as fundamental, dipole, quadrupole, and vortex modes. These modes reside in various band gaps of the photonic lattice. As the defect strength increases, defect modes move from lower band gaps to higher ones when the defect is repulsive, but remain within each band gap when the defect is attractive, similar to the one-dimensional case. The same phenomena are observed when the defect is held fixed while the applied dc field (which controls the lattice potential) increases. Lastly, if the defect is nonlocalized (i.e., it persists at large distances in the lattice), it is shown that defect modes can be embedded inside the continuous spectrum, and they can bifurcate out from edges of the continuous spectrum algebraically rather than exponentially.

  17. Hidden-symmetry-protected quantum pseudo-spin Hall effect in optical lattices

    NASA Astrophysics Data System (ADS)

    Hou, Jing-Min; Chen, Wei

    2016-06-01

    We propose a scheme to realize a Z2 topological insulator in a square optical lattice. Different from the conventional topological insulator protected by the time-reversal symmetry, here the optical lattice possesses a hidden symmetry, which is responsible for the present Z2 topological order. With a properly defined pseudospin, such a topological insulator is characterized by the helical edge states that exhibits pseudo-spin-momentum locking, so it can be considered as a quantum pseudo-spin Hall insulator. The Z2 topological invariant is derived and its experimental detection is discussed as well.

  18. Dynamics of polarized vortex solitons in nonlocal media with Bessel optical lattices.

    PubMed

    Zhang, Bingzhi; Chen, Zhifeng

    2015-09-21

    We investigate the formation of polarized vortex solitons in nonlocal media with Bessel optical lattices and show the various dynamics of these solitons. Particularly, the stable high-order polarized vortex solitons, which are not found in local media with Bessel optical lattices, are found in nonlocal media. It is found that the nonlocal nonlinearity plays an important role in the stability of these solitons which is similar to that of phase vortex solitons. However, we show that the dynamics of these polarized vortex solitons are quite different from the phase vortex solitons.

  19. Stability of binary condensates with spatial modulations of quintic nonlinearities in optical lattices

    NASA Astrophysics Data System (ADS)

    Mboumba, M. D.; Moubissi, A. B.; Ekogo, T. B.; Belobo Belobo, D.; Ben-Bolie, G. H.; Kofane, T. C.

    2015-10-01

    The stability and collective excitations of binary Bose-Einstein condensates with cubic and quintic nonlinearities in variable anharmonic optical lattices are investigated. By using the variational approach, the influences of the quintic nonlinearities and the shape of the external potential on the stability are discussed in details. It is found that the quintic intraspecies and interspecies interatomic interactions profoundly affect the stability criterion and collective excitations of the system. The shape dependent potential form that characterizes the optical lattice deeply alters the stability regions. Direct numerical simulations of the mean-field coupled Gross-Pitaevskii equation describing the system agree well with the analytical predictions.

  20. Competing bosonic condensates in optical lattice with a mixture of single and pair hoppings

    NASA Astrophysics Data System (ADS)

    Travin, V. M.; Kopeć, T. K.

    2017-01-01

    A system of ultra-cold atoms with single boson and pair tunneling of bosonic atoms is considered in an optical lattice at arbitrary temperature. A mean-field theory was applied to the extended Bose-Hubbard Hamiltonian describing the system in order to investigate the competition between superfluid and pair superfluid as a function of the chemical potential and the temperature. To this end we have applied a method based on the Laplace transform method for the efficient calculation of the statistical sum for the quantum Hamiltonian. These results may be of interest for experiments on cold atom systems in optical lattices.

  1. Design and Analysis of a Bypass Lattice for Optical Stochastic Cooling

    NASA Astrophysics Data System (ADS)

    Zholents, A.; Zolotorev, M.; Wan, W.

    1997-05-01

    An example of the beam line to bypass an optical amplifier in the method of Optical Stochastic Cooling is presented. Specific requirements to the lattice associated with cooling technique are considered. Tolerances to the alignment errors, tilt errors, magnetic field non linearities, power supply ripple are determined. A simple technique for initial tuning of the lattice to circumvent calibration errors of magnets and power supplies is proposed. Tolerances to the beam transverse oscillations and energy oscillations are defined. An experiment to test a bypass with the electron beam extracted from the Booster Synchrotron of the Advance Light Source of Lawrence Berkeley National Laboratory at the energy of 250 MeV is discussed.

  2. Linear optics design of negative momentum compaction lattices for PS2

    SciTech Connect

    Papaphilippou,Y.; de Maria,R.; Barranco, J.; Bartmann, W.; Benedikt, M.; Carli, C.; Goddard, B.; Peggs, S.; Trbojevic, D.

    2009-05-04

    In view of the CERN Proton Synchrotron proposed replacement with a new ring (PS2), a detailed optics design has been undertaken following the evaluation of several lattice options. The basic arc module consists of cells providing negative momentum compaction. The straight section is formed with a combination of FODO and quadrupole triplet cells, to accommodate the injection and extraction systems, in particular the H{sup -} injection elements. The arc is matched to the straight section with a dispersion suppressor and matching module. Different lattices are compared with respect to their linear optics functions, tuning flexibility and geometrical acceptance properties.

  3. A spectral collocation method for a rotating Bose-Einstein condensation in optical lattices

    NASA Astrophysics Data System (ADS)

    Li, Z.-C.; Chen, S.-Y.; Chien, C.-S.; Chen, H.-S.

    2011-06-01

    We extend the study of spectral collocation methods (SCM) in Li et al. (2009) [1] for semilinear elliptic eigenvalue problems to that for a rotating Bose-Einstein condensation (BEC) and a rotating BEC in optical lattices. We apply the Lagrange interpolants using the Legendre-Gauss-Lobatto points to derive error bounds for the SCM. The optimal error bounds are derived for both H-norm and L-norm. Extensive numerical experiments on a rotating Bose-Einstein condensation and a rotating BEC in optical lattices are reported. Our numerical results show that the convergence rate of the SCM is exponential, and is independent of the collocation points we choose.

  4. Flat bands, Dirac cones, and atom dynamics in an optical lattice

    SciTech Connect

    Apaja, V.; Hyrkaes, M.; Manninen, M.

    2010-10-15

    We study atoms trapped with a harmonic confinement in an optical lattice characterized by a flat band and Dirac cones. We show that such an optical lattice can be constructed which can be accurately described with the tight-binding or Hubbard models. In the case of fermions the release of the harmonic confinement removes fast atoms occupying the Dirac cones while those occupying the flat band remain immobile. Using exact diagonalization and dynamics we demonstrate that a similar strong occupation of the flat band does not happen in the bosonic case and furthermore that the mean-field model is not capable of describing the dynamics of the boson cloud.

  5. Self-consistent Hartree-Fock approach for interacting bosons in optical lattices

    NASA Astrophysics Data System (ADS)

    Lü, Qin-Qin; Patton, Kelly R.; Sheehy, Daniel E.

    2014-12-01

    A theoretical study of interacting bosons in a periodic optical lattice is presented. Instead of the commonly used tight-binding approach (applicable near the Mott-insulating regime of the phase diagram), the present work starts from the exact single-particle states of bosons in a cubic optical lattice, satisfying the Mathieu equation, an approach that can be particularly useful at large boson fillings. The effects of short-range interactions are incorporated using a self-consistent Hartree-Fock approximation, and predictions for experimental observables such as the superfluid transition temperature, condensate fraction, and boson momentum distribution are presented.

  6. Synthesis, Structure, and Magnetic Properties of A2Cu5(TeO3)(SO4)3(OH)4 (A = Na, K): The First Compounds with a 1D Kagomé Strip Lattice.

    PubMed

    Tang, Yingying; Guo, Wenbin; Xiang, Hongping; Zhang, Suyun; Yang, Ming; Cui, Meiyan; Wang, Nannan; He, Zhangzhen

    2016-01-19

    Two new tellurite-sulfates A2Cu5(TeO3)(SO4)3(OH)4 (A = Na, K) have been synthesized by a conventional hydrothermal method. Both compounds feature 1D kagomé strip structure built by distorted CuO6 octahedra, which can be regarded as the dimensional reduction of kagomé lattice. Magnetic measurements confirmed that the titled compounds possess antiferromagnetic ordering at low temperature, while a field-induced magnetic transition can be observed at critical field. To the best of our knowledge, this is the first time to obtain distorted kagomé strip compounds.

  7. Matter-wave propagation in optical lattices: geometrical and flat-band effects

    SciTech Connect

    Metcalf, Mekena; Chern, Gia-Wei; Di Ventra, Massimiliano; Chien, Chih-Chun

    2016-03-17

    Here we report that the geometry of optical lattices can be engineered allowing the study of atomic transport along paths arranged in patterns that are otherwise difficult to probe in the solid state. A question feasible to atomic systems is related to the speed of propagation of matter-waves as a function of the lattice geometry. To address this issue, we have investigated theoretically the quantum transport of non-interacting and weakly-interacting ultracold fermionic atoms in several 2D optical lattice geometries. We find that the triangular lattice has a higher propagation velocity compared to the square lattice, and the cross-linked square lattice has an even faster propagation velocity. The increase results from the mixing of the momentum states which leads to different group velocities in quantum systems. Standard band theory provides an explanation and allows for a systematic way to search and design systems with controllable matter-wave propagation. Moreover, the presence of a flat band such as in a two-leg ladder geometry leads to a dynamical density discontinuity due to its localized atoms. Lastly, we discuss possible realizations of those dynamical phenomena.

  8. A hybrid-trap BEC for radiofrequency-dressed optical lattice experiments

    NASA Astrophysics Data System (ADS)

    Lundblad, Nathan; Moody, Joanna

    2013-05-01

    Recent work in lattice-based ultracold atomic physics has focused on the development of increasingly precise and complex apparatus to push the boundaries of what can be measured with such systems. Historically such experiments have generally been confined to simple-cubic lattices with recent forays into systems both more fertile and more challenging, such as the honeycomb lattice or even the kagome net. We report progress towards nonstandard-geometry optical-lattice experiments using a recently-constructed BEC apparatus at Bates College. We summarize laser system construction, document the design and construction of a spin-flip Zeeman slower, present characterization of the laser cooling process, and present the results of magnetic trapping and evaporative cooling, including recent results showing transfer to a 1064 nm fiber-laser dipole trap and the resulting path to BEC. We also report on progress toward observation of adiabatic eigenstates in radiofrequency-dressed spin-dependent lattices loaded from said BEC, and present plans for observations of toroidal Wannier-function lattices. We also present a discussion of other possible nonstandard-geometry lattices that will be explored with this new apparatus. We acknowledge support from AFOSR and NSF.

  9. Light scattering from a randomly occupied optical lattice. II. The multiple scattering problem.

    PubMed

    Guo, Wei; Prasad, Sudhakar

    2003-05-01

    In this paper, we study the problem of multiple scattering of light from a randomly occupied optical lattice, thereby extending the first-order Born analysis of the previous paper. A full multiple-scattering analysis is essential to a complete understanding of the nature of light propagation inside a medium. Our calculations show that the incident wave, when resonant with the atomic medium, is rapidly extinguished due to multiple scattering. The decay constant depends critically on the incident wavelength, the lattice constant, the average number density of atoms, and their polarizability. Both the Bragg scattering amplitudes and directions are modified as a result of multiple scattering. Because of the random site occupation of an otherwise regular lattice structure, a coherent enhancement of the scattering cross section is also predicted to occur along a discrete set of directions that are related to the strictly backward direction by reciprocal lattice vectors.

  10. Dicke superradiance as nondestructive probe for the state of atoms in optical lattices

    NASA Astrophysics Data System (ADS)

    Brinke, Nicolai ten; Schützhold, Ralf

    2016-05-01

    We present a proposal for a probing scheme utilizing Dicke superradiance to obtain information about ultracold atoms in optical lattices. A probe photon is absorbed collectively by an ensemble of lattice atoms generating a Dicke state. The lattice dynamics (e.g., tunneling) affects the coherence properties of that Dicke state and thus alters the superradiant emission characteristics - which in turn provides insight into the lattice (dynamics). Comparing the Bose-Hubbard and the Fermi-Hubbard model, we find similar superradiance in the strongly interacting Mott insulator regime, but crucial differences in the weakly interacting (superfluid or metallic) phase. Furthermore, we study the possibility to detect whether a quantum phase transition between the two regimes can be considered adiabatic or a quantum quench.

  11. Production and manipulation of wave packets from ultracold atoms in an optical lattice

    NASA Astrophysics Data System (ADS)

    Pedersen, Poul L.; Gajdacz, Miroslav; Winter, Nils; Hilliard, Andrew J.; Sherson, Jacob F.; Arlt, Jan

    2013-08-01

    Within the combined potential of an optical lattice and a harmonic magnetic trap, it is possible to form matter wave packets by intensity modulation of the lattice. An analysis of the production and motion of these wave packets provides a detailed understanding of the dynamical evolution of the system. The modulation technique also allows for a controllable transfer (deexcitation) of atoms from such wave packets to a state bound by the lattice. Thus, it acts as a beam splitter for matter waves that can selectively address different bands, enabling the preparation of atoms in localized states. The combination of wave packet creation and deexcitation closely resembles the well-known method of pump-probe spectroscopy. Here, we use the deexcitation for spectroscopy of the anharmonicity of the combined potential. Finally, we demonstrate that lattice modulation can be used to excite matter wave packets to even higher momenta, producing fast wave packets with potential applications in precision measurements.

  12. Zitterbewegung with spin-orbit coupled ultracold atoms in a fluctuating optical lattice

    NASA Astrophysics Data System (ADS)

    Argonov, V. Yu; Makarov, D. V.

    2016-09-01

    The dynamics of non-interacting ultracold atoms with artificial spin-orbit coupling is considered. Spin-orbit coupling is created using two moving optical lattices with orthogonal polarizations. Our main goal is to study influence of lattice noise on Rabi oscillations. Special attention is paid to the phenomenon of the Zitterbewegung being trembling motion caused by Rabi transitions between states with different velocities. Phase and amplitude fluctuations of lattices are modelled by means of the two-dimensional stochastic Ornstein-Uhlenbeck process, also known as harmonic noise. In the the noiseless case the problem is solved analytically in terms of the momentum representation. It is shown that lattice noise significantly extends duration of the Zitterbewegung as compared to the noiseless case. This effect originates from noise-induced decoherence of Rabi oscillations.

  13. Toolbox for linear optics in a one-dimensional lattice via minimal control

    NASA Astrophysics Data System (ADS)

    Compagno, Enrico; Banchi, Leonardo; Bose, Sougato

    2015-08-01

    Tight-binding lattices offer a unique platform in which particles may be either static or mobile depending on the potential barrier between the sites. How to harness this mobility in a many-site lattice for useful operations is still an open question. We show how effective linear opticslike operations between arbitrary lattice sites can be implemented by a minimal local control which introduces a local impurity in the middle of the lattice. In particular we show how striking is the difference of the two possible correlations with and without the impurity. Our scheme enables the observation of the Hong-Ou-Mandel effect between distant wells without moving them next to each other with, e.g., tweezers. Moreover, we show that a tunable Mach-Zehnder interferometer is implemented adding a steplike potential, and we prove the robustness of our linear optics scheme to interparticle interactions.

  14. Geometric stability spectra of dipolar Bose gases in tunable optical lattices

    NASA Astrophysics Data System (ADS)

    Corson, John P.; Wilson, Ryan M.; Bohn, John L.

    2013-07-01

    We examine the stability of quasi-two-dimensional dipolar Bose-Einstein condensates in the presence of weak optical lattices of various geometries. We find that when the condensate possesses a roton-maxon quasiparticle dispersion, the conditions for stability exhibit a strong dependence both on the lattice geometry and the polarization tilt. This results in rich structures in the system's stability diagram akin to spectroscopic signatures. We show how these structures originate from the mode matching of rotons to the perturbing lattice. In the case of a one-dimensional lattice, some of the features emerge only when the polarization axis is tilted into the plane of the condensate. Our results suggest that the stability diagram may be used as a novel means to spectroscopically measure rotons in dipolar condensates.

  15. Bending light via adiabatic optical transition in longitudinally modulated photonic lattices.

    PubMed

    Han, Bin; Xu, Lei; Dou, Yiling; Xu, Jingjun; Zhang, Guoquan

    2015-10-29

    Bending light in a controllable way is desired in various applications such as beam steering, navigating and cloaking. Different from the conventional way to bend light by refractive index gradient, transformation optics or special beams through wavefront design such as Airy beams and surface plasmons, we proposed a mechanism to bend light via resonant adiabatic optical transition between Floquet-Bloch (FB) modes from different FB bands in longitudinally modulated photonic lattices. The band structure of longitudinally modulated photonic lattices was calculated by employing the concept of quasi-energy based on the Floquet-Bloch theory, showing the existence of band discontinuities at specific resonant points which cannot be revealed by the coupled-mode theory. Interestingly, different FB bands can be seamlessly connected at these resonant points in longitudinally modulated photonic lattices driven by adiabatically varying the longitudinal modulation period along the propagation direction, which stimulates the adiabatic FB mode transition between different FB bands.

  16. Design and fabrication of two-dimensional deterministic aperiodic photonic lattices by optical induction

    NASA Astrophysics Data System (ADS)

    Diebel, F.; Boguslawski, M.; Lučić, Nemanja M.; Jović Savić, Dragana M.; Denz, C.

    2015-03-01

    Light propagation in structured photonic media covers many fascinating wave phenomena resulting from the band structure of the underlying lattice. Recently, the focus turned towards deterministic aperiodic structures exhibiting distinctive band gap properties. To experimentally study these effects, optical induction of photonic refractive index landscapes turned out to be the method of choice to fabricate these structures. In this contribution, we present a paradigm change of photonic lattice design by introducing a holographic optical induction method based on pixel-like spatially multiplexed single-site nondiffracting Bessel beams. This technique allows realizing a huge class of two-dimensional photonic structures, including deterministic aperiodic golden-angle Vogel spirals, as well as Fibonacci lattices.

  17. Heterodimer of two distinguishable atoms in a one-dimensional optical lattice

    SciTech Connect

    Odong, Otim; Sanders, Jerome C.; Javanainen, Juha

    2011-09-15

    Within the Bose-Hubbard model, we theoretically determine the stationary states of two distinguishable atoms in a one-dimensional optical lattice and compare with the case of two identical bosons. A heterodimer has odd-parity dissociated states that do not depend on the interactions between the atoms, and the lattice momenta of the two atomic species may have different averages even for a bound state of the dimer. We discuss methods to detect the dimer. The different distributions of the quasimomenta of the two species may be observed in suitable time-of-flight experiments. Also, an asymmetry in the lineshape as a function of the modulation frequency may reveal the presence of the odd-parity dissociated states when a heterodimer is dissociated by modulating the depth of the optical lattice.

  18. Topological orbital superfluid with chiral d-wave order in a rotating optical lattice

    NASA Astrophysics Data System (ADS)

    Hao, Ningning; Guo, Huaiming; Zhang, Ping

    2017-08-01

    Topological superfluid is an exotic state of quantum matter that possesses a nodeless superfluid gap in the bulk and Andreev edge modes at the boundary of a finite system. Here, we study a multi-orbital superfluid driven by an attractive s-wave interaction in a rotating optical lattice. Interestingly, we find that the rotation induces the inter-orbital hybridization and drives the system into topological orbital superfluid in accordance with intrinsically chiral d-wave pairing characteristics. Thanks to the conservation of spin, the topological orbital superfluid supports four rather than two chiral Andreev edge modes at the boundary of the lattice. Moreover, we find that the intrinsic harmonic confining potential forms a circular spatial barrier which accumulates atoms and supports a mass current under the injection of small angular momentum as an external driving force. This feature provides an experimentally detectable phenomenon to verify the topological orbital superfluid with chiral d-wave order in a rotating optical lattice.

  19. Phases of a two-dimensional bose gas in an optical lattice.

    PubMed

    Jiménez-García, K; Compton, R L; Lin, Y-J; Phillips, W D; Porto, J V; Spielman, I B

    2010-09-10

    Ultracold atoms in optical lattices realize simple condensed matter models. We create an ensemble of ≈60 harmonically trapped 2D Bose-Hubbard systems from a 87Rb Bose-Einstein condensate in an optical lattice and use a magnetic resonance imaging approach to select a few 2D systems for study, thereby eliminating ensemble averaging. Our identification of the transition from superfluid to Mott insulator, as a function of both atom density and lattice depth, is in excellent agreement with a universal state diagram [M. Rigol, Phys. Rev. A 79 053605 (2009)] suitable for our trapped system. In agreement with theory, our data suggest a failure of the local density approximation in the transition region.

  20. Measuring finite-range phase coherence in an optical lattice using Talbot interferometry

    NASA Astrophysics Data System (ADS)

    Santra, Bodhaditya; Baals, Christian; Labouvie, Ralf; Bhattacherjee, Aranya B.; Pelster, Axel; Ott, Herwig

    2017-06-01

    One of the important goals of present research is to control and manipulate coherence in a broad variety of systems, such as semiconductor spintronics, biological photosynthetic systems, superconducting qubits and complex atomic networks. Over the past decades, interferometry of atoms and molecules has proven to be a powerful tool to explore coherence. Here we demonstrate a near-field interferometer based on the Talbot effect, which allows us to measure finite-range phase coherence of ultracold atoms in an optical lattice. We apply this interferometer to study the build-up of phase coherence after a quantum quench of a Bose-Einstein condensate residing in a one-dimensional optical lattice. Our technique of measuring finite-range phase coherence is generic, easy to adopt and can be applied in practically all lattice experiments without further modifications.

  1. Semiclassical solitons in strongly correlated systems of ultracold bosonic atoms in optical lattices

    SciTech Connect

    Demler, Eugene; Maltsev, Andrei

    2011-07-15

    Highlights: > Dynamics of their formation in strongly correlated systems of ultracold bosonic atoms in optical lattices. > Regime of very strong interactions between atoms, the so-called hard core bosons regime. > Character of soliton excitations is dramatically different from the usual Gross-Pitaevskii regime. - Abstract: We investigate theoretically soliton excitations and dynamics of their formation in strongly correlated systems of ultracold bosonic atoms in two and three dimensional optical lattices. We derive equations of nonlinear hydrodynamics in the regime of strong interactions and incommensurate fillings, when atoms can be treated as hard core bosons. When parameters change in one direction only we obtain Korteweg-de Vries type equation away from half-filling and modified KdV equation at half-filling. We apply this general analysis to a problem of the decay of the density step. We consider stability of one dimensional solutions to transverse fluctuations. Our results are also relevant for understanding nonequilibrium dynamics of lattice spin models.

  2. Bose-Einstein quantum phase transition in an optical lattice model

    SciTech Connect

    Aizenman, Michael; Lieb, Elliott H.; Seiringer, Robert; Solovej, Jan Philip; Yngvason, Jakob

    2004-08-01

    Bose-Einstein condensation (BEC) in cold gases can be turned on and off by an external potential, such as that presented by an optical lattice. We present a model of this phenomenon which we are able to analyze rigorously. The system is a hard core lattice gas at half of the maximum density and the optical lattice is modeled by a periodic potential of strength {lambda}. For small {lambda} and temperature, BEC is proved to occur, while at large {lambda} or temperature there is no BEC. At large {lambda} the low-temperature states are in a Mott insulator phase with a characteristic gap that is absent in the BEC phase. The interparticle interaction is essential for this transition, which occurs even in the ground state. Surprisingly, the condensation is always into the p=0 mode in this model, although the density itself has the periodicity of the imposed potential.

  3. Bending light via adiabatic optical transition in longitudinally modulated photonic lattices

    PubMed Central

    Han, Bin; Xu, Lei; Dou, Yiling; Xu, Jingjun; Zhang, Guoquan

    2015-01-01

    Bending light in a controllable way is desired in various applications such as beam steering, navigating and cloaking. Different from the conventional way to bend light by refractive index gradient, transformation optics or special beams through wavefront design such as Airy beams and surface plasmons, we proposed a mechanism to bend light via resonant adiabatic optical transition between Floquet-Bloch (FB) modes from different FB bands in longitudinally modulated photonic lattices. The band structure of longitudinally modulated photonic lattices was calculated by employing the concept of quasi-energy based on the Floquet-Bloch theory, showing the existence of band discontinuities at specific resonant points which cannot be revealed by the coupled-mode theory. Interestingly, different FB bands can be seamlessly connected at these resonant points in longitudinally modulated photonic lattices driven by adiabatically varying the longitudinal modulation period along the propagation direction, which stimulates the adiabatic FB mode transition between different FB bands. PMID:26511890

  4. Optically Induced Lattice Dynamics of hexagonal manganite using Ultrafast X-ray Diffraction

    NASA Astrophysics Data System (ADS)

    Lee, Hae Ja; Workman, J. B.; Hur, N.

    2005-03-01

    We have studied the picosecond lattice dynamics of optically pumped hexagonal manganite LuMnO3 using ultrafast x-ray diffraction. The results show a shift and broadening of the diffraction curve due to the stimulated lattice expansion. To understand the transient response of the lattice, the measured time- and angle-resolved diffraction curves are compared with a theoretical calculation based on dynamical diffraction theory modified for the hexagonal crystal structure of LuMnO3. Our simulations reveal that a large coupling coefficient between the a-b plane and the c-axis (c13) is required to the data. We compare this result to our previous coherent phonon studies of LuMnO3 using optical pump-probe spectroscopy.

  5. Amplified short-wavelength light scattered by relativistic electrons in the laser-induced optical lattice

    NASA Astrophysics Data System (ADS)

    Andriyash, I. A.; Tikhonchuk, V. T.; Malka, V.; D'Humières, E.; Balcou, Ph.

    2015-05-01

    The scheme of the x-ray free electron laser based on the optical undulator created by two overlapped transverse laser beams is analyzed. A kinetic theoretical description and an ad hoc numerical model are developed to account for the finite energy spread, angular divergence, and the spectral properties of the electron beam in the optical lattice. The theoretical findings are compared to the results of the one- and three-dimensional numerical modeling with the spectral free electron laser code plares.

  6. Matter-wave exact periodic solutions in optical lattices with periodic potential

    NASA Astrophysics Data System (ADS)

    Liu, Changfu; Zhu, Aijun

    2013-10-01

    Some special matter-wave periodic solutions for the Gross-Pitaevskii equation with periodic potential in the multidimensional optical lattices, are obtained through restricting parameters and some balance conditions between the optical potentials and interaction energies. The results show that the same type of periodic solutions in the same dimension possesses the same norm but different phases and they are all bounded. Especially, the numerics shows that two class (2+1)-dimensional periodic solutions are stable.

  7. Probing Many-Body Interactions in an Optical Lattice Clock (Preprint)

    DTIC Science & Technology

    2013-10-23

    framework that describes recently observed many-body effects during the interrogation of an optical lattice clock operated with thousands of fermionic...interactions, finite temperature effects and excitation inhomogeneity during the quantum dynamics of the interrogated atoms. Solutions of the master...so that Doppler and photon-recoil related effects on the transition frequency are eliminated. State-of-the-art neutral-atom-optical clocks have

  8. Engineering Stark Potentials for Precision Measurements: Optical Lattice Clock and Electrodynamic Surface Trap

    SciTech Connect

    Katori, Hidetoshi; Takamoto, Masao; Hachisu, Hidekazu; Fujiki, Jun; Higashi, Ryoichi; Yasuda, Masami; Kishimoto, Tetsuo

    2005-05-05

    Employing the engineered electric fields, we demonstrate novel platforms for precision measurements with neutral atoms. (1) Applying the light shift cancellation technique, atoms trapped in an optical lattice reveal 50-Hz-narrow optical spectrum, yielding nearly an order of magnitude improvement over existing neutral-atom-based clocks. (2) Surface Stark trap has been developed to manipulate scalar atoms that are intrinsically robust to decoherence.

  9. Low-acceleration instability of a Bose-Einstein condensate in an optical lattice.

    PubMed

    Zheng, Yi; Kostrun, Marijan; Javanainen, Juha

    2004-12-03

    We study a Bose-Einstein condensate in a one-dimensional accelerated optical lattice using the mean-field version of the Bose-Hubbard model. Reminiscent of recent experiments [M. Cristiani et al., Opt. Express 12, 4 (2004)], we find a new type of an instability in this system that occurs in the limit when the acceleration is small.

  10. Multiparticle Entanglement and Spatial Addressability of Ultracold Atoms in Optical Lattices

    DTIC Science & Technology

    2009-02-01

    Immanuel F. Bloch Stefan Kuhr Johannes Gutenberg-University Mainz Institute Fuer Physik/Quantum Mainz, Germany 55099 EOARD GRANT 07-3090...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Johannes Gutenberg University Mainz Institute Fuer Physik/Quantum Mainz, Germany 55099 8...Entanglement and Spatial Addressability of Ultracold Atoms in Optical Lattices Prof. Dr. Immanuel Bloch Dr. Stefan Kuhr Johannes

  11. Bose and Fermi Gases of Ultracold Ytterbium in a Triangular Optical Lattice

    NASA Astrophysics Data System (ADS)

    Thobe, Alexander; Doerscher, Soeren; Hundt, Bastian; Kochanke, Andre; Becker, Christoph; Sengstock, Klaus

    2013-05-01

    Quantum gases of alkaline-earth like atoms such as Calcium, Strontium and Ytterbium (Yb) open up exciting new possibilities for the study of many body physics in optical lattices, ranging from SU(N) symmetric spin Hamiltonians to the Kondo Lattice Model. Here, we present experimental studies of ultracold bosonic and fermionic Yb quantum gases. Unlike other experiments studying ultracold alkaline earth-like atoms, we have implemented a 2D-MOT instead of a Zeeman slower as a source of cold atoms. From the 2D-MOT, operating on the broad 1S0 -->1P1 transtition, the atoms are directly loaded into the 3D-MOT operating on a narrow intercombination line. The atoms are then evaporatively cooled to quantum degeneracy in a crossed optical dipole trap. With this setup we routinely produce BECs and degenerate Fermi gases of different Yb isotopes. Moreover, we present first results on spectroscopy of an interacting fermi gas on the ultranarrow 1S0 -->3P0 clock transition in a magic wavelength optical lattice. In future experiments, this spectroscopy will serve as a versatile tool for interaction sensing and selective addressing of atoms in a wavelength tunable, state dependent, triangular optical lattice, which we are currently implementing. This work is supported by DFG within SFB 925 and GrK 1355, as well as EU FETOpen (iSense).

  12. Critical temperature of noninteracting bosonic gases in cubic optical lattices at arbitrary integer fillings.

    PubMed

    Rakhimov, Abdulla; Askerzade, Iman N

    2014-09-01

    We have shown that the critical temperature of a Bose-Einstein condensate to a normal phase transition of noninteracting bosons in cubic optical lattices has a linear dependence on the filling factor, especially at large densities. The condensed fraction exhibits a linear power law dependence on temperature in contrast to the case of ideal homogeneous Bose gases.

  13. Ultracold bosons in a one-dimensional optical lattice chain: Newton's cradle and Bose enhancement effect

    NASA Astrophysics Data System (ADS)

    Wang, Ji-Guo; Yang, Shi-Jie

    2017-05-01

    We study a model to realize the long-distance correlated tunneling of ultracold bosons in a one-dimensional optical lattice chain. The model reveals the behavior of a quantum Newton's cradle, which is the perfect transfer between two macroscopic quantum states. Due to the Bose enhancement effect, we find that the resonantly tunneling through a Mott domain is greatly enhanced.

  14. Effective-mass analysis of Bose-Einstein condensates in optical lattices: Stabilization and levitation

    SciTech Connect

    Pu, H.; Zhang, W.; Meystre, P.; Baksmaty, L.O.; Bigelow, N.P.

    2003-04-01

    We investigate the time evolution of a Bose-Einstein condensate in a periodic optical potential. Using an effective mass formalism, we study the equation of motion for the envelope function modulating the Bloch states of the lattice potential. In particular, we show how the negative effective-mass affects the dynamics of the condensate.

  15. Landau-Zener tunneling of Bose-Einstein condensates in an optical lattice

    SciTech Connect

    Konotop, V.V.; Kevrekidis, P.G.; Salerno, M.

    2005-08-15

    A theory of the nonsymmetric Landau-Zener tunneling of Bose-Einstein condensates in deep optical lattices is presented. It is shown that periodic exchange of matter between the bands is described by a set of linearly coupled nonlinear Schroedinger equations. The key role of the modulational instability in rendering the interband transitions irreversible is highlighted.

  16. Incompressible states of a two-component Fermi gas in a double-well optical lattice

    SciTech Connect

    Crepin, Francois; Simon, Pascal; Citro, Roberta

    2010-07-15

    We propose a scheme to investigate the effect of frustration on the magnetic phase transitions of cold atoms confined in an optical lattice. We also demonstrate how to get two-leg spin ladders with frustrated spin-exchange coupling that display a phase transition from a spin liquid to a fully incompressible state. Further, various experimental quantities are analyzed for describing this phase.

  17. Direct Excitation of the Forbidden Clock Transition in Neutral {sup 174}Yb Atoms Confined to an Optical Lattice

    SciTech Connect

    Barber, Z.W.; Hoyt, C.W.; Oates, C.W.; Hollberg, L.; Taichenachev, A.V.; Yudin, V.I.

    2006-03-03

    We report direct single-laser excitation of the strictly forbidden (6s{sup 2}){sup 1}S{sub 0}{r_reversible}(6s6p){sup 3}P{sub 0} clock transition in {sup 174}Yb atoms confined to a 1D optical lattice. A small ({approx}1.2 mT) static magnetic field was used to induce a nonzero electric dipole transition probability between the clock states at 578.42 nm. Narrow resonance linewidths of 20 Hz (FWHM) with high contrast were observed, demonstrating a resonance quality factor of 2.6x10{sup 13}. The previously unknown ac Stark shift-canceling (magic) wavelength was determined to be 759.35{+-}0.02 nm. This method for using the metrologically superior even isotope can be easily implemented in current Yb and Sr lattice clocks and can create new clock possibilities in other alkaline-earth-like atoms such as Mg and Ca.

  18. Non-resonant gas-optical lattice interaction with feedback from the gas to the laser radiation

    NASA Astrophysics Data System (ADS)

    Kungurtsev, P. V.; Shevyrin, A. A.; Bondar, Ye. A.; Kashkovsky, A. V.; Shneider, M. N.; Gimelshein, S. F.

    2016-11-01

    Non-resonant interaction of polarized gas molecules with optical lattices is studied. Transient processes of gas particle optical trapping and wave propagation and refraction are considered, with the impact of gas density inhomogeneity on laser radiation taken into account. The computations are performed using SMILE++ Direct Simulation Monte Carlo code modified to incorporate lattice-gas interaction and a thin layer model. The influence of the size of the interaction region on the evolution of the optical field to steady state is demonstrated for a self-consistent interaction between the optical lattice and the gas. The proposed method will be useful for studying gas - laser field interaction under realistic experimental conditions.

  19. Optically induced zener tunneling in one-dimensional lattices.

    PubMed

    Fratalocchi, Andrea; Assanto, Gaetano; Brzdakiewicz, Kasia A; Karpierz, Mirek A

    2006-03-15

    We investigate Landau-Zener tunneling in one-dimensional liquid crystalline waveguide arrays by all-optical impression of acceleration with an additional beam. We derive the Zener model from the governing equations and demonstrate a novel approach to Floquet-Bloch band tunneling.

  20. Matter-wave propagation in optical lattices: geometrical and flat-band effects

    DOE PAGES

    Metcalf, Mekena; Chern, Gia-Wei; Di Ventra, Massimiliano; ...

    2016-03-17

    Here we report that the geometry of optical lattices can be engineered allowing the study of atomic transport along paths arranged in patterns that are otherwise difficult to probe in the solid state. A question feasible to atomic systems is related to the speed of propagation of matter-waves as a function of the lattice geometry. To address this issue, we have investigated theoretically the quantum transport of non-interacting and weakly-interacting ultracold fermionic atoms in several 2D optical lattice geometries. We find that the triangular lattice has a higher propagation velocity compared to the square lattice, and the cross-linked square latticemore » has an even faster propagation velocity. The increase results from the mixing of the momentum states which leads to different group velocities in quantum systems. Standard band theory provides an explanation and allows for a systematic way to search and design systems with controllable matter-wave propagation. Moreover, the presence of a flat band such as in a two-leg ladder geometry leads to a dynamical density discontinuity due to its localized atoms. Lastly, we discuss possible realizations of those dynamical phenomena.« less

  1. Imaging and addressing of individual fermionic atoms in an optical lattice

    NASA Astrophysics Data System (ADS)

    Trotzky, Stefan; Edge, Graham; Anderson, Rhys; Xu, Peihang; Venu, Vijin; Jervis, Dylan; McKay, Dave; Day, Ryan; Thywissen, Joseph

    2016-05-01

    The implementation of site-resolved imaging of atoms in short-period optical lattices constitutes a milestone achievement in the study of strongly correlated matter with these systems. Its realization with bosons six years ago has boosted progress in the field. In the last year, site-resolved imaging was demonstrated for fermions in five independent experiments. We present our newest results on site-resolved microscopy of ultracold 40 K in a 527nm-period optical lattice. Atoms remain pinned during imaging due to EIT cooling on the 770nm D1 transition. We observe pinning fidelities of up to 96% for an illumination time of 2.6s during which the atoms scatter > 2000 photons. A 0.8NA objective collects the fluorescence light to be imaged onto a EMCCD camera, giving a 600nm -wide PSF. In conjunction with the known lattice geometry, this allows us to reconstruct the lattice-site occupations from the images. The imaging technique is implemented in an apparatus capable of simulating the Fermi-Hubbard model. The use of tomographic tools enables us to select single lattice planes for background free imaging. We also address in-plane patterns with straight and circular boundaries in order to eliminate inhomogeneity effects on the imaging fidelity, or for controlled entropy removal.

  2. Magnetic field-induced spectroscopy of forbidden optical transitions with application to lattice-based optical atomic clocks.

    PubMed

    Taichenachev, A V; Yudin, V I; Oates, C W; Hoyt, C W; Barber, Z W; Hollberg, L

    2006-03-03

    We develop a method of spectroscopy that uses a weak static magnetic field to enable direct optical excitation of forbidden electric-dipole transitions that are otherwise prohibitively weak. The power of this scheme is demonstrated using the important application of optical atomic clocks based on neutral atoms confined to an optical lattice. The simple experimental implementation of this method--a single clock laser combined with a dc magnetic field--relaxes stringent requirements in current lattice-based clocks (e.g., magnetic field shielding and light polarization), and could therefore expedite the realization of the extraordinary performance level predicted for these clocks. We estimate that a clock using alkaline-earth-like atoms such as Yb could achieve a fractional frequency uncertainty of well below 10(-17) for the metrologically preferred even isotopes.

  3. Three-level Haldane-like model on a dice optical lattice

    NASA Astrophysics Data System (ADS)

    Andrijauskas, T.; Anisimovas, E.; RačiÅ«nas, M.; Mekys, A.; Kudriašov, V.; Spielman, I. B.; JuzeliÅ«nas, G.

    2015-09-01

    We consider ultracold atoms in a two-dimensional optical lattice of the dice geometry in a tight-binding regime. The atoms experience a laser-assisted tunneling between the nearest neighbor sites of the dice lattice accompanied by the momentum recoil. This allows one to engineer staggered synthetic magnetic fluxes over plaquettes, and thus pave a way towards the realization of topologically nontrivial band structures. In such a lattice the real-valued next-nearest neighbor transitions are not needed to reach a topological regime. Yet, such transitions can increase a variety of the obtained topological phases. The dice lattice represents a triangular Bravais lattice with a three-site basis consisting of a hub site connected to two rim sites. As a consequence, the dice lattice supports three energy bands. From this point of view, our model can be interpreted as a generalization of the paradigmatic Haldane model which is reproduced if one of the two rim sublattices is eliminated. We demonstrate that the proposed upgrade of the Haldane model creates a significant added value, including an easy access to topological semimetal phases relying only on the nearest neighbor coupling, as well as enhanced topological band structures featuring Chern numbers higher than one leading to physics beyond the usual quantum Hall effect. The numerical investigation is supported and complemented by an analytical scheme based on the study of singularities in the Berry connection.

  4. Characterizing the antiferromagnetic ordering of fermions in a compensated optical lattice

    NASA Astrophysics Data System (ADS)

    Duarte, P. M.; Hart, R. A.; Yang, T. L.; Liu, X.; Hulet, R. G.; Paiva, T. C. L.; Huse, D.; Scalettar, R.; Trivedi, N.

    2014-05-01

    We realize the Fermi-Hubbard model with fermionic 6Li atoms in a three-dimensional, red-detuned optical lattice. The lattice is compensated by the addition of three blue-detuned gaussian beams which overlap each of the lattice laser beams, but are not retro-reflected. Using the compensated lattice potential, we have reached temperatures low enough to produce antiferromagnetic (AF) spin correlations, which we detect via Bragg scattering of light. The variation of the measured AF correlations as a function of the Hubbard interaction strength, U / t , provides a way to determine the temperature of the atoms in the lattice by comparison with quantum Monte Carlo calculations. This method suggests our temperature is in the range of 2-3 times the Néel ordering temperature. In this poster we present our Bragg scattering results along with our studies of the effect of the compensating potential in helping us cool the atoms in the lattice and also enlarge the size of the AF phase. Work supported by DARPA, ONR, NSF and The Welch Foundation.

  5. Extended Bose Hubbard model of interacting bosonic atoms in optical lattices: From superfluidity to density waves

    SciTech Connect

    Mazzarella, G.; Giampaolo, S. M.; Illuminati, F.

    2006-01-15

    For systems of interacting, ultracold spin-zero neutral bosonic atoms, harmonically trapped and subject to an optical lattice potential, we derive an Extended Bose Hubbard (EBH) model by developing a systematic expansion for the Hamiltonian of the system in powers of the lattice parameters and of a scale parameter, the lattice attenuation factor. We identify the dominant terms that need to be retained in realistic experimental conditions, up to nearest-neighbor interactions and nearest-neighbor hoppings conditioned by the on-site occupation numbers. In the mean field approximation, we determine the free energy of the system and study the phase diagram both at zero and at finite temperature. At variance with the standard on site Bose Hubbard model, the zero-temperature phase diagram of the EBH model possesses a dual structure in the Mott insulating regime. Namely, for specific ranges of the lattice parameters, a density wave phase characterizes the system at integer fillings, with domains of alternating mean occupation numbers that are the atomic counterparts of the domains of staggered magnetizations in an antiferromagnetic phase. We show as well that in the EBH model, a zero-temperature quantum phase transition to pair superfluidity is, in principle, possible, but completely suppressed at the lowest order in the lattice attenuation factor. Finally, we determine the possible occurrence of the different phases as a function of the experimentally controllable lattice parameters.

  6. Optical lattice-like cladding waveguides by direct laser writing: fabrication, luminescence, and lasing.

    PubMed

    Nie, Weijie; He, Ruiyun; Cheng, Chen; Rocha, Uéslen; Rodríguez Vázquez de Aldana, Javier; Jaque, Daniel; Chen, Feng

    2016-05-15

    We report on the fabrication of optical lattice-like waveguide structures in an Nd:YAP laser crystal by using direct femtosecond laser writing. With periodically arrayed laser-induced tracks, the waveguiding cores can be located in either the regions between the neighbored tracks or the central zone surrounded by a number of tracks as outer cladding. The polarization of the femtosecond laser pulses for the inscription has been found to play a critical role in the anisotropic guiding behaviors of the structures. The confocal photoluminescence investigations reveal different stress-induced modifications of the structures inscribed by different polarization of the femtosecond laser beam, which are considered to be responsible for the refractive index changes of the structures. Under optical pump at 808 nm, efficient waveguide lasing at ∼1  μm wavelength has been realized from the optical lattice-like structure, which exhibits potential applications as novel miniature light sources.

  7. 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.

  8. Optically Induced Lattice Dynamics Probed with Ultrafast X-ray Diffraction

    NASA Astrophysics Data System (ADS)

    Lee, H. J.; Taylor, A. J.; Averitt, R. D.; Lim, D.; Workman, J.; Roberts, J. P.; McCulloch, Q.; Hof, D. E.; Funk, D. J.; Hur, N.; Cheong, S. W.

    2004-03-01

    We report our initial studies using ultrafast x-ray diffraction for the characterization of lattice dynamics in optically pumped manganites. For these studies, single crystal LuMnO3 is pumped with an 800 nm 100fs Ti:Sapphire laser. The induced lattice dynamics are observed using Al K-alpha x-rays, generated by focusing a portion of the same laser onto a moving Al wire. The x-rays are relay imaged onto the sample using a spherically bent quartz 10-10 crystal. The single crystal LuMnO3 is oriented with the c-axis perpendicular to the face of the crystal, with the x-rays probing the [002] reflection. An overview of the experiment and results to date along with a comparison with optical pump-optical probe measurements of the coherent phonon dynamics will be presented.

  9. Quantum dynamics of disordered bosons in an optical lattice

    NASA Astrophysics Data System (ADS)

    Lin, Chien-Hung; Sensarma, Rajdeep; Sengupta, K.; Das Sarma, S.

    2012-12-01

    We study the equilibrium and nonequilibrium properties of strongly interacting bosons on a lattice in the presence of a random bounded disorder potential. Using a Gutzwiller projected variational technique, we study the equilibrium phase diagram of the disordered Bose-Hubbard model and obtain the Mott insulator, Bose glass, and superfluid phases. We also study the nonequilibrium response of the system under a periodic temporal drive where, starting from the superfluid phase, the hopping parameter is ramped down linearly in time, and back to its initial value. We study the density of excitations created, the change in the superfluid order parameter, and the energy pumped into the system in this process as a function of the inverse ramp rate τ. For the clean case the density of excitations goes to a constant, while the order parameter and energy relax as 1/τ and 1/τ2 respectively. With disorder, the excitation density decays exponentially with τ, with the decay rate increasing with the disorder, to an asymptotic value independent of the disorder. The energy and change in order parameter also decrease as τ is increased.

  10. Optical resonance problem in metamaterial arrays: a lattice dynamics approach

    NASA Astrophysics Data System (ADS)

    Liu, Wanguo

    2016-11-01

    A systematic dynamic theory is established to deal with the optical collective resonance in metamaterial arrays. As a reference model, we consider an infinite split ring resonator (SRR) array illuminated by a linearly polarized wave and introduce an N-degree-of-freedom forced oscillator equation to simplify the coupled-mode vibration problem. We derive a strict formula of resonance frequency (RF) and its adjustable range from the steady-state response. Unlike a single SRR possesses invariant RF, it successfully explains the mechanism of RF shift effect in the SRR array when the incident angle changes. Instead of full wave analysis, only one or two adjacent resonance modes can give an accurate response line shape. Our approach is applicable for metallic arrays with any N-particle cell at all incident angles and well matched with numerical results. It provides a versatile way to study the vibration dynamics in optical periodic many-body systems.

  11. Defect modes of a Bose-Einstein condensate in an optical lattice with a localized impurity

    SciTech Connect

    Brazhnyi, Valeriy A.; Konotop, Vladimir V.; Perez-Garcia, Victor M.

    2006-08-15

    We study defect modes of a Bose-Einstein condensate in an optical lattice with a localized defect within the framework of the one-dimensional Gross-Pitaevskii equation. It is shown that for a significant range of parameters the defect modes can be accurately described by an expansion over Wannier functions, whose envelope is governed by the coupled nonlinear Schroedinger equations with a {delta} impurity. The stability of the defect modes is verified by direct numerical simulations of the underlying Gross-Pitaevskii equation with a periodic and defect potentials. We also discuss possibilities of driving defect modes through the lattice and suggest ideas for their experimental generation.

  12. Quantum Two-breathers Formed by Ultracold Bosonic Atoms in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Tang, Bing

    2016-06-01

    Two-discrete breathers are the bound states of two localized modes that can appear in classical nonlinear lattices. I investigate the quantum signature of two-discrete breathers in the system of ultracold bosonic atoms in optical lattices, which is modeled as Bose-Hubbard model containing n bosons. When the number of bosons is small, I find numerically quantum two-breathers by making use of numerical diagonalization and perturbation theory. For the cases of a large number of bosons, I can successfully construct quantum two-breather states in the Hartree approximation.

  13. Optical techniques for Rydberg physics in lattice geometries. A technical guide

    NASA Astrophysics Data System (ADS)

    Naber, Julian B.; Vos, Jannie; Rengelink, Robert J.; Nusselder, Rosanne J.; Davtyan, David

    2016-12-01

    We address the technical challenges when performing quantum information experiments with ultracold Rydberg atoms in lattice geometries. We discuss the following key aspects: (i) the coherent manipulation of atomic ground states, (ii) the coherent excitation of Rydberg states, and (iii) spatial addressing of individual lattice sites. We briefly review methods and solutions which have been successfully implemented, and give examples based on our experimental apparatus. This includes an optical phase-locked loop, an intensity and frequency stabilization setup for lasers, and a nematic liquid-crystal spatial light modulator.

  14. Magic Wavelength to Make Optical Lattice Clocks Insensitive to Atomic Motion

    SciTech Connect

    Katori, Hidetoshi; Hashiguchi, Koji; Il'inova, E. Yu.; Ovsiannikov, V. D.

    2009-10-09

    In a standing wave of light, a difference in spatial distributions of multipolar atom-field interactions may introduce atomic-motion dependent clock uncertainties in optical lattice clocks. We show that the magic wavelength can be defined so as to eliminate the spatial mismatch in electric dipole, magnetic dipole, and electric quadrupole interactions for specific combinations of standing waves by allowing a spatially constant light shift arising from the latter two interactions. Experimental prospects of such lattices used with a blue magic wavelength are discussed.

  15. Observation and cancellation of a perturbing dc stark shift in strontium optical lattice clocks.

    PubMed

    Lodewyck, Jérôme; Zawada, Michal; Lorini, Luca; Gurov, Mikhail; Lemonde, Pierre

    2012-03-01

    We report on the observation of a dc Stark frequency shift at the 10-(13) level by comparing two strontium optical lattice clocks. This frequency shift arises from the presence of electric charges trapped on dielectric surfaces placed under vacuum close to the atomic sample. We show that these charges can be eliminated by shining UV light on the dielectric surfaces, and characterize the residual dc Stark frequency shift on the clock transition at the 10-(18) level by applying an external electric field. This study shows that the dc Stark shift can play an important role in the accuracy budget of lattice clocks, and should be duly taken into account.

  16. Micromagic Clock: Microwave Clock Based on Atoms in an Engineered Optical Lattice

    SciTech Connect

    Beloy, K.; Derevianko, A.; Dzuba, V. A.; Flambaum, V. V.

    2009-03-27

    We propose a new class of atomic microwave clocks based on the hyperfine transitions in the ground state of aluminum or gallium atoms trapped in optical lattices. For such elements magic wavelengths exist at which both levels of the hyperfine doublet are shifted at the same rate by the lattice laser field, canceling its effect on the clock transition. A similar mechanism for the magic wavelengths may work in microwave hyperfine transitions in other atoms which have the fine-structure multiplets in the ground state.

  17. Magic wavelength to make optical lattice clocks insensitive to atomic motion.

    PubMed

    Katori, Hidetoshi; Hashiguchi, Koji; Il'inova, E Yu; Ovsiannikov, V D

    2009-10-09

    In a standing wave of light, a difference in spatial distributions of multipolar atom-field interactions may introduce atomic-motion dependent clock uncertainties in optical lattice clocks. We show that the magic wavelength can be defined so as to eliminate the spatial mismatch in electric dipole, magnetic dipole, and electric quadrupole interactions for specific combinations of standing waves by allowing a spatially constant light shift arising from the latter two interactions. Experimental prospects of such lattices used with a blue magic wavelength are discussed.

  18. Vibrational mechanics in an optical lattice: controlling transport via potential renormalization.

    PubMed

    Wickenbrock, A; Holz, P C; Wahab, N A Abdul; Phoonthong, P; Cubero, D; Renzoni, F

    2012-01-13

    We demonstrate theoretically and experimentally the phenomenon of vibrational resonance in a periodic potential, using cold atoms in an optical lattice as a model system. A high-frequency (HF) drive, with a frequency much larger than any characteristic frequency of the system, is applied by phase modulating one of the lattice beams. We show that the HF drive leads to the renormalization of the potential. We used transport measurements as a probe of the potential renormalization. The very same experiments also demonstrate that transport can be controlled by the HF drive via potential renormalization.

  19. Bragg resonances and Zener tunneling in quasiperiodic two-dimensional optical lattices and photonic crystals

    SciTech Connect

    Shchesnovich, Valery S.

    2007-09-15

    Nonresonant Zener tunneling in decagonal quasiperiodic structures in two spatial dimensions is defined by its relation to Bragg resonance and is studied by direct numerical simulations and an analytical approach. It is shown that, in the shallow lattice limit, the tunneling dynamics about the Bragg resonances is described by the multilevel Landau-Zener-Majorana models, which capture the essential peaks of the complicated Fourier spectrum. The results have applications to dynamics of cold atoms and Bose-Einstein condensates in quasiperiodic optical lattices, light propagation in quasiperiodic photonic crystals, and ultrasonic experiments with quasiperiodic structures.

  20. Atomic Landau-Zener tunneling in Fourier-synthesized optical lattices.

    PubMed

    Salger, Tobias; Geckeler, Carsten; Kling, Sebastian; Weitz, Martin

    2007-11-09

    We report on an experimental study of quantum transport of atoms in variable periodic optical potentials. The band structure of both ratchet-type asymmetric and symmetric lattice potentials is explored. The variable atom potential is realized by superimposing a conventional standing wave potential of lambda/2 spatial periodicity with a fourth-order multiphoton potential of lambda/4 periodicity. We find that the Landau-Zener tunneling rate between the first and the second excited Bloch band depends critically on the relative phase between the two spatial lattice harmonics.

  1. Atomic Landau-Zener Tunneling in Fourier-Synthesized Optical Lattices

    SciTech Connect

    Salger, Tobias; Geckeler, Carsten; Kling, Sebastian; Weitz, Martin

    2007-11-09

    We report on an experimental study of quantum transport of atoms in variable periodic optical potentials. The band structure of both ratchet-type asymmetric and symmetric lattice potentials is explored. The variable atom potential is realized by superimposing a conventional standing wave potential of {lambda}/2 spatial periodicity with a fourth-order multiphoton potential of {lambda}/4 periodicity. We find that the Landau-Zener tunneling rate between the first and the second excited Bloch band depends critically on the relative phase between the two spatial lattice harmonics.

  2. Coherent Atom Optics With Fast Metastable Beams: Metastable Helium Diffraction By 1D and 2D Magnetized Reflection Gratings

    SciTech Connect

    Grucker, J.; Baudon, J.; Karam, J.-C.; Perales, F.; Ducloy, M.; Bocvarski, V.

    2007-04-23

    1D and 2D reflection gratings (Permalloy stripes or dots deposited on silicon), immersed in an external homogeneous static magnetic field, are used to study 1D and 2D diffraction of fast metastable helium atoms He* (23S1). Both the grazing incidence used here and the repulsive potential (for sub-level m = -1) generated by the magnetisation reduce the quenching effect. This periodically structured potential is responsible for the diffraction in the incidence plane as well as for the diffraction in the perpendicular plane.

  3. High-Accuracy Measure of Atomic Polarizability in an Optical Lattice Clock

    DTIC Science & Technology

    2011-12-11

    AND SUBTITLE Sa. CONTRACT NUMBER High-Accuracy Measurement of Atomic Polarizability in an VV911~-11 - 1 -0202 Optical Lattice Clock Sb. GRANT NUMBER...modem optical atomic clock through blackbody radiation. By employing an ultracold, trapped atomic ensemble and high stability optical clock, we...1,U~ (1,’T, TI~ \\ 1\\ ( ,., ) Tl-.~ ~1 ~~1,1~ +.-~~+: ~~~ 1 ··~~~··+~:~+. • ...1 • • ~ +~ ··~~-~ 1S. SUBJECT TERMS atomic frequency standards

  4. Optical lattices of excitons in InGaN/GaN quantum well systems

    SciTech Connect

    Chaldyshev, V. V. Bolshakov, A. S. Zavarin, E. E.; Sakharov, A. V.; Lundin, V. V.; Tsatsulnikov, A. F.; Yagovkina, M. A.

    2015-01-15

    Optical lattices of excitons in periodic systems of InGaN quantum wells with GaN barriers are designed, implemented, and investigated. Due to the collective interaction of quasi-two-dimensional excitons with light and a fairly high binding energy of excitons in GaN, optical Bragg reflection at room temperature is significantly enhanced. To increase the resonance optical response of the system, new structures with two quantum wells in a periodic supercell are designed and implemented. Resonance reflection of 40% at room temperatures for structures with 60 periods is demonstrated.

  5. Optical Selection Rules in Spin-Orbit Coupled Systems on Honeycomb Lattice

    NASA Astrophysics Data System (ADS)

    Yanagi, Yuki; Kusunose, Hiroaki

    2017-08-01

    We investigate the optical properties in a minimal model of spin-orbit coupled systems on honeycomb lattice at half-filling. In particular, the absorption of circularly polarized light in the charge and antiferromagnetic ordered states is studied, and spin-valley selective excitation depending on the handedness of the light is found. It is shown that the optical selection rules plainly differ according to the type of broken symmetries and topological properties of the electronic states. Consequently, the spin-valley selectivity in optical absorption abruptly changes at the topological transition caused by the change of magnitude of the order parameters.

  6. Frequency ratios of optical lattice clocks at the 17th decimal place

    NASA Astrophysics Data System (ADS)

    Katori, Hidetoshi

    2016-05-01

    Optical lattice clocks benefit from a low quantum-projection noise by simultaneously interrogating a large number of atoms, which are trapped in an optical lattice tuned to the ``magic wavelength'' to largely cancel out light shift perturbation in the clock transition. About a thousand atoms enable the clocks to achieve 10-18 instability in a few hours of operation, allowing intensive investigation and control of systematic uncertainties. As optical lattice clocks have reached inaccuracies approaching 10-18, it is now the uncertainty of the SI second (~ 10-16) itself that restricts the measurement of the absolute frequencies of such optical clocks. Direct comparisons of optical clocks are, therefore, the only way to investigate and utilize their superb performance beyond the SI second. In this presentation, we report on frequency comparisons of optical lattice clocks with neutral strontium (87 Sr), ytterbium (171 Yb) and mercury (199 Hg) atoms. By referencing cryogenic Sr clocks, we determine frequency ratios, νYb/νSr and νHg/νSr, of a cryogenic Yb clock and a Hg clock with uncertainty at the mid 10-17 level. Such ratios provide an access to search for temporal variation of the fundamental constants. We also present remote comparisons between cryogenic Sr clocks located at RIKEN and the University of Tokyo over a 30-km-long phase-stabilized fiber link. The gravitational red shift Δν /ν0 ~ 1.1× 10-18 Δh cm-1 reads out the height difference of Δh ~ 15 m between the two clocks with uncertainty of 5 cm, which demonstrates a step towards relativistic geodesy. ERATO, JST.

  7. Two-dimensional bright and dark-in-bright dipolar Bose-Einstein condensate solitons on a one-dimensional optical lattice

    NASA Astrophysics Data System (ADS)

    Adhikari, S. K.

    2016-08-01

    We study the statics and dynamics of anisotropic, stable, bright and dark-in-bright dipolar quasi-two-dimensional Bose-Einstein condensate (BEC) solitons on a one-dimensional (1D) optical-lattice (OL) potential. These solitons mobile in a plane perpendicular to a 1D OL trap can have both repulsive and attractive contact interactions. Dark-in-bright solitons are the excited states of bright solitons. The solitons, when subjected to a small perturbation, exhibit sustained breathing oscillation. Dark-in-bright solitons can be created by phase imprinting a bright soliton. At medium velocities the collision between two solitons is found to be quasi-elastic. Results are demonstrated by a numerical simulation of the three-dimensional mean-field Gross-Pitaevskii equation in three spatial dimensions employing realistic interaction parameters for a dipolar 164Dy BEC.

  8. Coexistence of Mott and superfluid domains of bosons confined in optical lattice

    NASA Astrophysics Data System (ADS)

    Khanore, Mukesh; Dey, Bishwajyoti

    2015-06-01

    We investigate ground state properties of the attractive Bose-gas confined on square optical lattice and superimposed wine-bottle-bottom or Mexican hat trap potential. The system is modeled by two-dimensional Bose-Hubbard model with attractive interactions and inhomogeneous lattice potential. We calculate the energy spectrum, the on-site number fluctuation, local density and local compressibility using numerical exact diagonalization method for incommensurate lattice filling. The trap potential has several degenerate minimum sites distributed along a ring at the wine-bottle-bottom. It is shown that beyond a certain value of the attractive interaction strength there is phase coherent condensate on these degenerate sites with finite value of the on-site number fluctuation and local compressibility giving rise to localized superfluidity or superfluidity on a ring. For the same value of the interaction strength the non-degenerate sites produces Mott region.

  9. Weyl points and topological nodal superfluids in a face-centered-cubic optical lattice

    NASA Astrophysics Data System (ADS)

    Lang, Li-Jun; Zhang, Shao-Liang; Law, K. T.; Zhou, Qi

    2017-07-01

    We point out that a face-centered-cubic (fcc) optical lattice, which can be realized by a simple scheme using three lasers, provides one a highly controllable platform for creating Weyl points and topological nodal superfluids in ultracold atoms. In noninteracting systems, Weyl points automatically arise in the Floquet band structure when shaking such fcc lattices, and sophisticated design of the tunneling is not required. More interestingly, in the presence of attractive interaction between two hyperfine spin states, which experience the same shaken fcc lattice, a three-dimensional topological nodal superfluid emerges, and Weyl points show up as the gapless points in the quasiparticle spectrum. One could either create a double Weyl point of charge 2, or split it into two Weyl points of charge 1, which can be moved in the momentum space by tuning the interactions. Correspondingly, the Fermi arcs at the surface may be linked with each other or separated as individual ones.

  10. Properties of dirty bosons in disordered optical lattices

    NASA Astrophysics Data System (ADS)

    Ray, Ushnish

    The study of the disordered Bose-Hubbard model is key to understanding the interplay of disorder and interactions. Despite many studies with uniform diagonal disorder, few have inquired into experimental realizations with an additional correlated off-diagonal disorder. The presence of a trap and finite temperature effects in experiments lead to multiple domains of the Superfluid, Mott-Insulator/normal and the Bose-Glass phase. Previous studies using approximate theories produced results that are not in accordance with experiments. Stochastic Series Expansion is a finite temperature technique that can solve Bosonic lattice Hamiltonians exactly for large systems. Here, studies are performed for an extensive range of parameters using disorder distributions that are similar to experiments. Insights are first acquired by studying trap-free situations. Constant density calculations show that, although the qualitative features of the phase diagram remain robust between speckle disorder and uniform box disorder, there are quantitative differences. Studies of the Bose-glass phase explicitly show that it is composed of superfluid puddles that are stable to finite temperature effects for large temperature ranges. Finite temperature behavior of a strongly correlated system reveals that at unit filling, the transition temperature of the superfluid is increased due to the addition of disorder. Inquires are then extended to discern the properties of trapped systems. Extensive calculations show that domain-like structures that develop can be rigorously demarcated using the single-particle eigenstates extracted from the single-particle density matrix. Observables are calculated for the system at the single-site and global scales, showing that intermediate length scales provide the correct description of the physics of the domains in these systems. These techniques are used to conclusively show the possibility of the re-entrant superfluid that should be accessible to experiments

  11. Spectroscopy for cold atom gases in periodically modulated optical lattice potential

    NASA Astrophysics Data System (ADS)

    Tokuno, Akiyuki; Giamarchi, Thierry

    2011-03-01

    Cold atoms in optical lattices are vigorously studied experimentally and theoretically as one of the candidates for a quantum simulator. At the same time, further development of probes to microscopic structure of systems is needed. We propose a novel spectroscopy in cold atom experiments by use of periodic phase-modulation of optical lattice potentials. Corresponding to the statistics of atoms, we formulate the different observables: The energy absorption rate for bosonic atom gases, and the doublon production rate for fermionic atom gases. These observables are formulated within the linear response theory. Interestingly they are given by the imaginary part of the retarded current-current correlation function which is familiar as a quantity corresponding to an optical conductivity. As an example, we discuss one-dimensional Mott insulating state, and also compare our spectroscopy with another known spectroscopy by amplitude-modulation of an optical lattice. This work was supported in part by the Swiss SNF under MaNEP and division II.

  12. Cold atom dynamics in a quantum optical lattice potential.

    PubMed

    Maschler, Christoph; Ritsch, Helmut

    2005-12-31

    We study a generalized cold atom Bose-Hubbard model, where the periodic optical potential is formed by a cavity field with quantum properties. On the one hand, the common coupling of all atoms to the same mode introduces cavity-mediated long-range atom-atom interactions, and, on the other hand, atomic backaction on the field introduces atom-field entanglement. This modifies the properties of the associated quantum phase transitions and allows for new correlated atom-field states, including superposition of different atomic quantum phases. After deriving an approximative Hamiltonian including the new long-range interaction terms, we exhibit central physical phenomena at generic configurations of few atoms in few wells. We find strong modifications of population fluctuations and next-nearest-neighbor correlations near the phase transition point.

  13. Controlling chaos of a Bose-Einstein condensate loaded into a moving optical Fourier-synthesized lattice.

    PubMed

    Chacón, R; Bote, D; Carretero-González, R

    2008-09-01

    We study the chaotic properties of steady-state traveling-wave solutions of the particle number density of a Bose-Einstein condensate with an attractive interatomic interaction loaded into a traveling optical lattice of variable shape. We demonstrate theoretically and numerically that chaotic traveling steady states can be reliably suppressed by small changes of the traveling optical lattice shape while keeping the remaining parameters constant. We find that the regularization route as the optical lattice shape is continuously varied is fairly rich, including crisis phenomena and period-doubling bifurcations. The conditions for a possible experimental realization of the control method are discussed.

  14. Energy band gap and optical transition of metal ion modified double crossover DNA lattices.

    PubMed

    Dugasani, Sreekantha Reddy; Ha, Taewoo; Gnapareddy, Bramaramba; Choi, Kyujin; Lee, Junwye; Kim, Byeonghoon; Kim, Jae Hoon; Park, Sung Ha

    2014-10-22

    We report on the energy band gap and optical transition of a series of divalent metal ion (Cu(2+), Ni(2+), Zn(2+), and Co(2+)) modified DNA (M-DNA) double crossover (DX) lattices fabricated on fused silica by the substrate-assisted growth (SAG) method. We demonstrate how the degree of coverage of the DX lattices is influenced by the DX monomer concentration and also analyze the band gaps of the M-DNA lattices. The energy band gap of the M-DNA, between the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO), ranges from 4.67 to 4.98 eV as judged by optical transitions. Relative to the band gap of a pristine DNA molecule (4.69 eV), the band gap of the M-DNA lattices increases with metal ion doping up to a critical concentration and then decreases with further doping. Interestingly, except for the case of Ni(2+), the onset of the second absorption band shifts to a lower energy until a critical concentration and then shifts to a higher energy with further increasing the metal ion concentration, which is consistent with the evolution of electrical transport characteristics. Our results show that controllable metal ion doping is an effective method to tune the band gap energy of DNA-based nanostructures.

  15. Realization of the Harper Hamiltonian with Artificial Gauge Fields in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Miyake, Hirokazu; Siviloglou, Georgios; Kennedy, Colin; Burton, William Cody; Ketterle, Wolfgang

    2014-03-01

    Systems of charged particles in magnetic fields have led to many discoveries in science-such as the integer and fractional quantum Hall effects-and have become important paradigms of quantum many-body physics. We have proposed and implemented a scheme which realizes the Harper Hamiltonian, a lattice model for charged particles in magnetic fields, whose energy spectrum is the fractal Hofstadter butterfly. We experimentally realize this Hamiltonian for ultracold, charge neutral bosonic particles of 87Rb in a two-dimensional optical lattice by creating an artificial gauge field using laser-assisted tunneling and a potential energy gradient provided by gravity. Laser-assisted tunneling processes are characterized by studying the expansion of the atoms in the lattice. Furthermore, this scheme can be extended to realize spin-orbit coupling and the spin Hall effect for neutral atoms in optical lattices by modifying the motion of atoms in a spin-dependent way by laser recoil and Zeeman shifts created with a magnetic field gradient. Major advantages of our scheme are that it does not rely on near-resonant laser light to couple different spin states and should work even for fermionic particles. Our work is a step towards studying novel topological phenomena with ultracold atoms. Currently at the RAND Corporation.

  16. Coherent driving and freezing of bosonic matter wave in an optical Lieb lattice.

    PubMed

    Taie, Shintaro; Ozawa, Hideki; Ichinose, Tomohiro; Nishio, Takuei; Nakajima, Shuta; Takahashi, Yoshiro

    2015-11-01

    Although kinetic energy of a massive particle generally has quadratic dependence on its momentum, a flat, dispersionless energy band is realized in crystals with specific lattice structures. Such macroscopic degeneracy causes the emergence of localized eigenstates and has been a key concept in the context of itinerant ferromagnetism. We report the realization of a "Lieb lattice" configuration with an optical lattice, which has a flat energy band as the first excited state. Our optical lattice potential has various degrees of freedom in its manipulation, which enables coherent transfer of a Bose-Einstein condensate into the flat band. In addition to measuring lifetime of the flat band population for different tight-binding parameters, we investigate the inter-sublattice dynamics of the system by projecting the sublattice population onto the band population. This measurement clearly shows the formation of the localized state with the specific sublattice decoupled in the flat band, and even detects the presence of flat-band breaking perturbations, resulting in the delocalization. Our results will open up the possibilities of exploring the physics of flat bands with a highly controllable quantum system.

  17. Chaos and band structure in a three-dimensional optical lattice.

    PubMed

    Boretz, Yingyue; Reichl, L E

    2015-04-01

    Classical chaos is known to affect wave propagation because it signifies the presence of broken symmetries. The effect of chaos has been observed experimentally for matter waves, electromagnetic waves, and acoustic waves. When these three types of waves propagate through a spatially periodic medium, the allowed propagation energies form bands. For energies in the band gaps, no wave propagation is possible. We show that optical lattices provide a well-defined system that allows a study of the effect of chaos on band structure. We have determined the band structure of a body-centered-cubic optical lattice for all theoretically possible couplings, and we find that the band structure for those lattices realizable in the laboratory differs significantly from that expected for the bands in an "empty" body-centered-cubic crystal. However, as coupling is increased, the lattice becomes increasingly chaotic and it becomes possible to produce band structure that has behavior qualitatively similar to the "empty" body-centered-cubic band structure, although with fewer degeneracies.

  18. Evolution from BCS to Berezinskii-Kosterlitz-Thouless Superfluidity in One-Dimensional Optical Lattices

    SciTech Connect

    Iskin, M.; Sa de Melo, C. A. R.

    2009-10-16

    We analyze the finite temperature phase diagram of fermion mixtures in one-dimensional optical lattices as a function of interaction strength. At low temperatures, the system evolves from an anisotropic three-dimensional Bardeen-Cooper-Schrieffer (BCS) superfluid to an effectively two-dimensional Berezinskii-Kosterlitz-Thouless (BKT) superfluid as the interaction strength increases. We calculate the critical temperature as a function of interaction strength, and identify the region where the dimensional crossover occurs for a specified optical lattice potential. Finally, we show that the dominant vortex excitations near the critical temperature evolve from multiplane elliptical vortex loops in the three-dimensional regime to planar vortex-antivortex pairs in the two-dimensional regime, and we propose a detection scheme for these excitations.

  19. Controlling and detecting spin correlations of ultracold atoms in optical lattices.

    PubMed

    Trotzky, Stefan; Chen, Yu-Ao; Schnorrberger, Ute; Cheinet, Patrick; Bloch, Immanuel

    2010-12-31

    We report on the controlled creation of a valence bond state of delocalized effective-spin singlet and triplet dimers by means of a bichromatic optical superlattice. We demonstrate a coherent coupling between the singlet and triplet states and show how the superlattice can be employed to measure the singlet-fraction employing a spin-blockade effect. Our method provides a reliable way to detect and control nearest-neighbor spin correlations in many-body systems of ultracold atoms. Being able to measure these correlations is an important ingredient in studying quantum magnetism in optical lattices. We furthermore employ a SWAP operation between atoms which are part of different triplets, thus effectively increasing their bond-length. Such a SWAP operation provides an important step towards the massively parallel creation of a multiparticle entangled state in the lattice.

  20. Selective distillation phenomenon in two-species Bose-Einstein condensates in open boundary optical lattices

    PubMed Central

    Bai, Xiao-Dong; Zhang, Mei; Xiong, Jun; Yang, Guo-Jian; Deng, Fu-Guo

    2015-01-01

    We investigate the formation of discrete breathers (DBs) and the dynamics of the mixture of two-species Bose-Einstein condensates (BECs) in open boundary optical lattices using the discrete nonlinear Schrödinger equations. The results show that the coupling of intra- and interspecies interaction can lead to the existence of pure single-species DBs and symbiotic DBs (i.e., two-species DBs). Furthermore, we find that there is a selective distillation phenomenon in the dynamics of the mixture of two-species BECs. One can selectively distil one species from the mixture of two-species BECs and can even control dominant species fraction by adjusting the intra- and interspecies interaction in optical lattices. Our selective distillation mechanism may find potential application in quantum information storage and quantum information processing based on multi-species atoms. PMID:26597592

  1. Topological states in a ladder-like optical lattice containing ultracold atoms in higher orbital bands

    NASA Astrophysics Data System (ADS)

    Li, Xiaopeng; Zhao, Erhai; Vincent Liu, W.

    2013-02-01

    Topological insulators are classified according to their symmetries. Discovery of them in electronic solids is thus restricted by orbital and crystalline symmetries available in nature. Synthetic quantum matter, such as the recent double-well optical lattices loaded with s and p orbital ultracold atoms, can exploit symmetries and interaction beyond natural conditions. Here we unveil a topological phase of interacting fermionic atoms on a two-leg ladder derived from the above experimental optical lattice by dimension reduction. The topological band structure originates from the staggered phases of sp orbital tunnelling, requiring neither spin-orbit coupling nor other known mechanisms like p-wave pairing, artificial gauge field or rotation. Upon crossing over to two-dimensional coupled ladders, the edge modes from individual ladder form a parity-protected flat band at zero energy. Experimental signatures are found in density correlations and phase transitions to trivial band and Mott insulators.

  2. Fractional quantum Hall states of dipolar fermions in a strained optical lattice

    NASA Astrophysics Data System (ADS)

    Fujita, Hiroyuki; Nakagawa, Yuya O.; Ashida, Yuto; Furukawa, Shunsuke

    2016-10-01

    We study strongly correlated ground states of dipolar fermions in a honeycomb optical lattice with spatial variations in hopping amplitudes. Similar to strained graphene, such nonuniform hopping amplitudes produce valley-dependent pseudomagnetic fields for fermions near the two Dirac points, resulting in the formation of Landau levels. The dipole moments aligned perpendicular to the honeycomb plane yield a long-range repulsive interaction. By exact diagonalization in the zeroth-Landau-level basis, we show that this repulsive interaction stabilizes a variety of valley-polarized fractional quantum Hall states such as Laughlin and composite-fermion states. The present system thus offers an intriguing platform for emulating fractional quantum Hall physics in a static optical lattice. We calculate the energy gaps above these incompressible states and discuss the temperature scales required for their experimental realization.

  3. Selective distillation phenomenon in two-species Bose-Einstein condensates in open boundary optical lattices

    NASA Astrophysics Data System (ADS)

    Bai, Xiao-Dong; Zhang, Mei; Xiong, Jun; Yang, Guo-Jian; Deng, Fu-Guo

    2015-11-01

    We investigate the formation of discrete breathers (DBs) and the dynamics of the mixture of two-species Bose-Einstein condensates (BECs) in open boundary optical lattices using the discrete nonlinear Schrödinger equations. The results show that the coupling of intra- and interspecies interaction can lead to the existence of pure single-species DBs and symbiotic DBs (i.e., two-species DBs). Furthermore, we find that there is a selective distillation phenomenon in the dynamics of the mixture of two-species BECs. One can selectively distil one species from the mixture of two-species BECs and can even control dominant species fraction by adjusting the intra- and interspecies interaction in optical lattices. Our selective distillation mechanism may find potential application in quantum information storage and quantum information processing based on multi-species atoms.

  4. Disorder-induced heating of ultracold neutral plasmas created from atoms in partially filled optical lattices

    NASA Astrophysics Data System (ADS)

    Murphy, D.; Sparkes, B. M.

    2016-08-01

    We quantify the disorder-induced heating (DIH) of ultracold neutral plasmas (UCNPs) created from cold atoms in optical lattices with partial filling fractions, using a conservation of energy model involving the spatial correlations of the initial state and the equation of state in thermal equilibrium for a one-component plasma. We show, for experimentally achievable filling fractions, that the ionic Coulomb coupling parameter could be increased to a degree comparable to other proposed DIH-mitigation schemes. Molecular dynamics simulations were performed with compensation for finite-size and periodic boundary effects, which agree with calculations using the model. Reduction of DIH using optical lattices will allow for the study of strongly coupled plasma physics using low-density, low-temperature, laboratory-based plasmas, and lead to improved brightness in UCNP-based cold electron and ion beams, where DIH is otherwise a fundamental limitation to beam focal sizes and diffraction imaging capability.

  5. Dzyaloshinskii-Moriya Interaction and Spiral Order in Spin-orbit Coupled Optical Lattices

    PubMed Central

    Gong, Ming; Qian, Yinyin; Yan, Mi; Scarola, V. W.; Zhang, Chuanwei

    2015-01-01

    We show that the recent experimental realization of spin-orbit coupling in ultracold atomic gases can be used to study different types of spin spiral order and resulting multiferroic effects. Spin-orbit coupling in optical lattices can give rise to the Dzyaloshinskii-Moriya (DM) spin interaction which is essential for spin spiral order. By taking into account spin-orbit coupling and an external Zeeman field, we derive an effective spin model in the Mott insulator regime at half filling and demonstrate that the DM interaction in optical lattices can be made extremely strong with realistic experimental parameters. The rich finite temperature phase diagrams of the effective spin models for fermions and bosons are obtained via classical Monte Carlo simulations. PMID:26014458

  6. Ultracold two-body dynamics in optical lattices with topological singularities

    NASA Astrophysics Data System (ADS)

    Aghamalyan, Davit; Simoni, Andrea; Launay, Jean-Michel

    2016-05-01

    We study bound levels of two particles trapped in a 2D optical lattice. We use a short-range potential tuned to reproduce typical experimental conditions. Near-threshold bound states are computed using a spectral element discretization approach that guarantees exponential precision in the numerical results. High computational efficiency is attained due to the very sparse nature of the Hamiltonian in this representation. The calculated wavefunction is analyzed both in real and in momentum space. We perform calculations both for standard separable optical potentials and for lattice with topological singularities (Dirac cones) in the band structure. Extension to the calculation of scattering states will be addressed. This work was supported by the Agence Nationale de la Recherche (Contract No. ANR-12-BS04-0020-01).

  7. Surface-modified Wannier-Stark states in a one-dimensional optical lattice

    NASA Astrophysics Data System (ADS)

    Maury, A.; Donaire, M.; Gorza, M.-P.; Lambrecht, A.; Guérout, R.

    2016-11-01

    We study the energy spectrum of atoms trapped in a vertical one-dimensional optical lattice in close proximity to a reflective surface. We propose an effective model to describe the interaction between the atoms and the surface at any distance. Our model includes the long-range Casimir-Polder potential together with a short-range Lennard-Jones potential, which are considered nonperturbatively with respect to the optical lattice potential. We find an intricate energy spectrum which contains a pair of loosely bound states localized close to the surface in addition to a surface-modified Wannier-Stark ladder at long distances. Atomic interferometry involving those loosely bound atom-surface states is proposed to probe the adsorption dynamics of atoms on mirrors.

  8. Optical absorption enhancement in silicon nanowire arrays with a large lattice constant for photovoltaic applications.

    PubMed

    Lin, Chenxi; Povinelli, Michelle L

    2009-10-26

    In this paper, we use the transfer matrix method to calculate the optical absorptance of vertically-aligned silicon nanowire (SiNW) arrays. For fixed filling ratio, significant optical absorption enhancement occurs when the lattice constant is increased from 100 nm to 600 nm. The enhancement arises from an increase in field concentration within the nanowire as well as excitation of guided resonance modes. We quantify the absorption enhancement in terms of ultimate efficiency. Results show that an optimized SiNW array with lattice constant of 600 nm and wire diameter of 540 nm has a 72.4% higher ultimate efficiency than a Si thin film of equal thickness. The enhancement effect can be maintained over a large range of incidence angles.

  9. Artificial topological models based on a one-dimensional spin-dependent optical lattice

    NASA Astrophysics Data System (ADS)

    Zheng, Zhen; Pu, Han; Zou, Xubo; Guo, Guangcan

    2017-01-01

    Topological matter is a popular topic in both condensed matter and cold-atom research. In the past decades, a variety of models have been identified with fascinating topological features. Some, but not all, of the models can be found in materials. As a fully controllable system, cold atoms trapped in optical lattices provide an ideal platform to simulate and realize these topological models. Here we present a proposal for synthesizing topological models in cold atoms based on a one-dimensional spin-dependent optical lattice potential. In our system, features such as staggered tunneling, staggered Zeeman field, nearest-neighbor interaction, beyond-near-neighbor tunneling, etc. can be readily realized. They underlie the emergence of various topological phases. Our proposal can be realized with current technology and hence has potential applications in quantum simulation of topological matter.

  10. Probe of three-dimensional chiral topological insulators in an optical lattice.

    PubMed

    Wang, S-T; Deng, D-L; Duan, L-M

    2014-07-18

    We propose a feasible experimental scheme to realize a three-dimensional chiral topological insulator with cold fermionic atoms in an optical lattice, which is characterized by an integer topological invariant distinct from the conventional Z(2) topological insulators and has a remarkable macroscopic zero-energy flat band. To probe its property, we show that its characteristic surface states--the Dirac cones--can be probed through time-of-flight imaging or Bragg spectroscopy and the flat band can be detected via measurement of the atomic density profile in a weak global trap. The realization of this novel topological phase with a flat band in an optical lattice will provide a unique experimental platform to study the interplay between interaction and topology and open new avenues for application of topological states.

  11. Geopotential measurements with synchronously linked optical lattice clocks

    NASA Astrophysics Data System (ADS)

    Takano, Tetsushi; Takamoto, Masao; Ushijima, Ichiro; Ohmae, Noriaki; Akatsuka, Tomoya; Yamaguchi, Atsushi; Kuroishi, Yuki; Munekane, Hiroshi; Miyahara, Basara; Katori, Hidetoshi

    2016-10-01

    According to Einstein's theory of relativity, the passage of time changes in a gravitational field. On Earth, raising a clock by 1 cm increases its apparent tick rate by 1.1 parts in 1018, allowing chronometric levelling through comparison of optical clocks. Here, we demonstrate such geopotential measurements by determining the height difference of master and slave clocks separated by 15 km with an uncertainty of 5 cm. A subharmonic of the master clock laser is delivered through a telecom fibre to synchronously operate the distant clocks. Clocks operated under such phase coherence reject clock laser noise and facilitate proposals for linking clocks and interferometers. Taken over half a year, 11 measurements determine the fractional frequency difference between the two clocks to be 1,652.9(5.9) × 10-18, consistent with an independent measurement by levelling and gravimetry. Our system demonstrates a building block for an internet of clocks, which may constitute ‘quantum benchmarks’, serving as height references with dynamic responses.

  12. Visibility of cold atomic gases in optical lattices for finite temperatures

    SciTech Connect

    Hoffmann, Alexander; Pelster, Axel

    2009-05-15

    In nearly all experiments with ultracold atoms time-of-flight pictures are the only data available. In this paper we present an analytical strong-coupling calculation for those time-of-flight pictures of bosons in a three-dimensional optical lattice in the Mott phase. This allows us to determine the visibility, which quantifies the contrast of peaks in the time-of-flight pictures, and we suggest how to use it as a thermometer.

  13. From Cooper pairs to Luttinger liquids with bosonic atoms in optical lattices.

    PubMed

    Paredes, B; Cirac, J I

    2003-04-18

    We propose a scheme to observe strongly correlated fermionic phenomena with bosonic atoms in optical lattices. For different values of the sign and strength of the scattering lengths, it is possible to reach either a "superconducting" regime, where the system exhibits atomic pairing, or a Luttinger liquid behavior. We identify the range of parameters where these phenomena appear, illustrate our predictions with numerical calculations, and show how to detect the presence of pairing.

  14. A variational solution to solitons in parity-time symmetric optical lattices

    NASA Astrophysics Data System (ADS)

    Hu, Sumei; Chen, Haibo; Hu, Wei

    2017-09-01

    A variational technique is established to study the fundamental solitons in parity-time symmetric optical lattices. The variational results show that the fundamental solitons can exist in the semi-infinite gap. The variational method can be fit for the solitons whose real part of field is symmetrical or antisymmetrical. Following numerical simulations, the variational results are in good agreement with the numerical results.

  15. Nonlinear Sensing With Collective States of Ultracold Atoms in Optical Lattices

    DTIC Science & Technology

    2015-04-02

    Office P.O. Box 12211 Research Triangle Park , NC 27709-2211 Nonlinear quantum sensing, quantum metrology, ultracold atoms, optical lattices REPORT...not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. University of Maryland - College Park Research...Administration 3112 Lee Building College Park , MD 20742 -5141 31-Aug-2014 ABSTRACT Nonlinear Sensing With Collective States of Ultracold Atoms in

  16. The Bose-Hubbard model: from Josephson junction arrays to optical lattices

    NASA Astrophysics Data System (ADS)

    Bruder, C.; Fazio, R.; Schön, G.

    2005-09-01

    [Dedicated to Bernhard Mühlschlegel on the occasion ofhis 80th birthday]The Bose-Hubbard model is a paradigm for the study of strongly correlated bosonic systems. We review some of its properties with emphasis on the implications on quantum phase transitions of Josephson junction arrays and quantum dynamics of topological excitations as well as the properties of ultra-cold atoms in optical lattices.

  17. Optical gain in Si/SiO2 lattice: Experimental evidence with nanosecond pulses

    NASA Astrophysics Data System (ADS)

    Khriachtchev, Leonid; Räsänen, Markku; Novikov, Sergei; Sinkkonen, Juha

    2001-08-01

    Experimental evidence of population inversion and amplified spontaneous emission was found for Si nanocrystallites embedded in SiO2 surrounding under pumping with 5 ns light pulses at 380, 400, and 500 nm. As an important property, our experiments show a short lifetime of the population inversion allowing a generation of short (a few nanosecond) amplified light pulses in the Si/SiO2 lattice. The estimate for optical gain in the present samples is 6 cm-1 at 720 nm.

  18. Nonlinear patterns in Bose-Einstein condensates in dissipative optical lattices

    SciTech Connect

    Bludov, Yu. V.; Konotop, V. V.

    2010-01-15

    It is shown that the one-dimensional nonlinear Schroedinger equation with a dissipative periodic potential, nonlinear losses, and a linear pump allow for the existence of stable nonlinear Bloch states which are attractors. The model describes a Bose-Einstein condensate with inelastic two- and three-body interactions loaded in an optical lattice with losses due to inelastic interactions of the atoms with photons.

  19. Fiber-optic signal processor with applications to matrix-vector multiplication and lattice filtering.

    PubMed

    Tur, M; Goodman, J W; Moslehi, B; Bowers, J E; Shaw, H J

    1982-09-01

    A new fiber-optic signal processor is proposed to implement systolic matrix-vector multipliers and lattice filters. 10(9) multiplications/sec can be achieved with currently available components for matrix-vector multiplications that involve Toeplitz matrices. A 2 x 2 (Toeplitz) matrix-vector multiplier has been experimentally demonstrated using single-mode fibers and directional couplers. The filtering characteristics of the device are also discussed.

  20. Higher-order effects on uncertainties of clocks of Mg atoms in an optical lattice

    NASA Astrophysics Data System (ADS)

    Ovsiannikov, V. D.; Marmo, S. I.; Mokhnenko, S. N.; Palchikov, V. G.

    2017-01-01

    Multipole, nonlinear and anharmonic effects on the optical-lattice-based clocks of Mg atoms are evaluated theoretically. Dipole polarizabilities, hyperpolarizabilities and multipolar polarizabilities for Mg atoms are calculated in the single-electron approximation with the use of analytical presentations for the wave and Green’s functions in the modified model-potential approach. For comparison, the data are also given for atoms of the group IIb elements (Zn, Cd, Hg).

  1. Investigation of Density Perturbations in Molecular Nitrogen Formed by Pulsed Optical Lattices

    DTIC Science & Technology

    2011-06-01

    configuration with the appropriate gas properties. During the last 0.02% of the simulation, cells were sampled to give flow field values. With...from the lattice induced gas gratings was measured as a function of ambient pressure and pump energy. The results obtained from the numerical...an Optical Cavity,” Proceedings of the 26th International Symposium on Rarefied Gas Dynamics, ed. T. Abe, (AIP, New York, 2009), pp. 533-538 8

  2. Delocalizing transition in one-dimensional condensates in optical lattices due to inhomogeneous interactions

    SciTech Connect

    Bludov, Yu. V.; Brazhnyi, V. A.; Konotop, V. V.

    2007-08-15

    It is shown that inhomogeneous nonlinear interactions in a Bose-Einstein condensate loaded in an optical lattice can result in a delocalizing transition in one dimension, which sharply contrasts to the known behavior of discrete and periodic systems with homogeneous nonlinearity. The transition can be originated either by decreasing the amplitude of the linear periodic potential or by the change of the mean value of the periodic nonlinearity. The dynamics of the delocalizing transition is studied.

  3. On the possibility of observing chaotic motion of cold atoms in rigid optical lattices

    NASA Astrophysics Data System (ADS)

    Prants, S. V.; Kon'kov, L. E.

    2017-06-01

    The possibility of experimental observation of chaotic motion of cold atoms in a one-dimensional rigid optical lattice without any modulation of its parameters and additional impact is demonstrated theoretically and numerically. This effect of deterministic chaos arises near the optical resonance due to the nonlinear coupling of electronic and mechanical degrees of freedom in the atom. In a certain range of resonance detunings, at each crossing of the lattice-forming standing wave node by the atom, the atomic dipole moment changes pseudorandomly in a step-like manner, accompanied by an appropriate change in the atom momentum. This leads to the effect of chaotic wandering of atoms, possessing the properties of the classical deterministic chaos, namely, to the exponential sensitivity of atomic trajectories to small variations of the initial conditions and/or the control parameters. With time, part of atoms from the initial cloud changes the direction of their motion to the opposite one, which can be detected in a real experiment. Numerical experiments with lithium atoms with the spontaneous emission taken into account show that by varying the laser radiation intensity (normalised detuning of resonance) in the rigid optical lattice, one can implement the transition from the regular regime of the atomic motion to the chaotic wandering in a real experiment.

  4. Analysis of the blackbody-radiation shift in an ytterbium optical lattice clock

    NASA Astrophysics Data System (ADS)

    Xu, Yi-Lin; Xu, Xin-Ye

    2016-10-01

    We accurately evaluate the blackbody-radiation shift in a 171Yb optical lattice clock by utilizing temperature measurement and numerical simulation. In this work. three main radiation sources are considered for the blackbody-radiation shift, including the heated atomic oven, the warm vacuum chamber, and the room-temperature vacuum windows. The temperatures on the outer surface of the vacuum chamber are measured during the clock operation period by utilizing seven calibrated temperature sensors. Then we infer the temperature distribution inside the vacuum chamber by numerical simulation according to the measured temperatures. Furthermore, we simulate the temperature variation around the cold atoms while the environmental temperature is fluctuating. Finally, we obtain that the total blackbody-radiation shift is -1.289(7) Hz with an uncertainty of 1.25 × 10-17 for our 171Yb optical lattice clock. The presented method is quite suitable for accurately evaluating the blackbody-radiation shift of the optical lattice clock in the case of lacking the sensors inside the vacuum chamber. Project supported by the National Key Basic Research and Development Program of China (Grant No. 2012CB821302), the National Natural Science Foundation of China (Grant No. 11134003), the National High Technology Research and Development Program of China (Grant No. 2014AA123401), and the Shanghai Excellent Academic Leaders Program of China (Grant No. 12XD1402400).

  5. Quantum phases from competing short- and long-range interactions in an optical lattice.

    PubMed

    Landig, Renate; Hruby, Lorenz; Dogra, Nishant; Landini, Manuele; Mottl, Rafael; Donner, Tobias; Esslinger, Tilman

    2016-04-28

    Insights into complex phenomena in quantum matter can be gained from simulation experiments with ultracold atoms, especially in cases where theoretical characterization is challenging. However, these experiments are mostly limited to short-range collisional interactions; recently observed perturbative effects of long-range interactions were too weak to reach new quantum phases. Here we experimentally realize a bosonic lattice model with competing short- and long-range interactions, and observe the appearance of four distinct quantum phases--a superfluid, a supersolid, a Mott insulator and a charge density wave. Our system is based on an atomic quantum gas trapped in an optical lattice inside a high-finesse optical cavity. The strength of the short-range on-site interactions is controlled by means of the optical lattice depth. The long (infinite)-range interaction potential is mediated by a vacuum mode of the cavity and is independently controlled by tuning the cavity resonance. When probing the phase transition between the Mott insulator and the charge density wave in real time, we observed a behaviour characteristic of a first-order phase transition. Our measurements have accessed a regime for quantum simulation of many-body systems where the physics is determined by the intricate competition between two different types of interactions and the zero point motion of the particles.

  6. Bloch oscillations of cold atoms in two-dimensional optical lattices

    SciTech Connect

    Kolovsky, A. R.; Korsch, H. J.

    2003-06-01

    Bloch oscillations of cold atoms in two-dimensional optical lattices are studied. The cases of separable and nonseparable potentials are compared by simulating the wave-packet dynamics. For these two classes of optical potential, the Bloch oscillations were found to be qualitatively the same in the case of a weak static field but fundamentally different in the case of a strong field. In addition, the dynamics of the atoms in a double-period potential (which can easily be realized in two dimensions) is studied for the regime of a weak static field.

  7. Optical NOR logic gate design on square lattice photonic crystal platform

    SciTech Connect

    D’souza, Nirmala Maria Mathew, Vincent

    2016-05-06

    We numerically demonstrate a new configuration of all-optical NOR logic gate with square lattice photonic crystal (PhC) waveguide using finite difference time domain (FDTD) method. The logic operations are based on interference effect of optical waves. We have determined the operating frequency range by calculating the band structure for a perfectly periodic PhC using plane wave expansion (PWE) method. Response time of this logic gate is 1.98 ps and it can be operated with speed about 513 GB/s. The proposed device consists of four linear waveguides and a square ring resonator waveguides on PhC platform.

  8. Antiresonant reflection and inhibited coupling in hollow-core square lattice optical fibres.

    PubMed

    Argyros, Alexander; Leon-Saval, Sergio G; Pla, Jarryd; Docherty, Andrew

    2008-04-14

    We propose a guidance mechanism in hollow-core optical fibres dominated by antiresonant reflection from struts of solid material in the cladding. Resonances with these struts determine the high loss bands of the fibres, and vector effects become important in determining the width of these bands through the non-degeneracy of the TE and TM polarised strut modes near cut-off. Away from resonances the light is confined through the inhibited coupling mechanism. This is demonstrated in a square lattice hollow-core microstructured polymer optical fibre.

  9. Optical NOR logic gate design on square lattice photonic crystal platform

    NASA Astrophysics Data System (ADS)

    D'souza, Nirmala Maria; Mathew, Vincent

    2016-05-01

    We numerically demonstrate a new configuration of all-optical NOR logic gate with square lattice photonic crystal (PhC) waveguide using finite difference time domain (FDTD) method. The logic operations are based on interference effect of optical waves. We have determined the operating frequency range by calculating the band structure for a perfectly periodic PhC using plane wave expansion (PWE) method. Response time of this logic gate is 1.98 ps and it can be operated with speed about 513 GB/s. The proposed device consists of four linear waveguides and a square ring resonator waveguides on PhC platform.

  10. Formation of Photonic Structures in Photorefractive Lithium Niobate by 1D and 2D Bessel-like Optical Fields

    NASA Astrophysics Data System (ADS)

    Inyushov, A.; Safronova, P.; Trushnikov, I.; Sarkyt, A.; Shandarov, V.

    2017-06-01

    Both, one-dimensional (1D) and two-dimensional (2D) Bessel-like beams with different topology of 2D beam cross-sections are formed from Gaussian laser beams using the amplitude masks and Fresnel biprisms. These almost diffraction-free light fields with wavelengths of 532 and 633 nm can change the refractive indices of photorefractive lithium niobate samples and form within them the nonlinear photonic diffraction structures. The characteristics of photonic structures induced in this way are studied by diffraction of monochromatic light with wavelengths of 633 and 532 nm.

  11. Fiber-lattice accumulator design considerations for optical sigma delta analog-to-digital converters

    NASA Astrophysics Data System (ADS)

    Pace, Phillip E.; Bewley, S. A.; Powers, John P.

    2000-06-01

    Integrated optical sigma-delta ((Sigma) (Delta) ) analog-to- digital converters (ADCs) use a pulsed laser to oversample an input signal at two Mach-Zehnder interferometers. A fiber-lattice accumulator is embedded within a feedback loop around a single-bit quantizer to spectrally shape the quantization noise to fall outside the signal band of interest. Decimation filtering is applied to the quantizer output to construct the input signal with high resolution. Applications of integrated optical (Sigma) (Delta) ADCs include digitizing wideband radio-frequency signals directly at an antenna (digital antenna). In this paper, a novel fiber- lattice accumulator design is presented, and a coherent simulation of an integrated optical first-order, single-bit (Sigma) (Delta) ADC is reported. The accumulator leakage resulting from a mismatch in the optical circuit parameters is quantified. A time-domain analysis is presented, and the simulation results from an all-electronic (Sigma) (Delta) ADC are presented for comparison. A frequency-domain analysis of a ten times oversampling (n equals 4 bits) simulation is used to compare the dynamic performance parameters, including the spurious-free dynamic range, signal-to-noise-plus-distortion ratio, and effective number of bits. The formation of image frequencies when the accumulator is overloaded (i.e., the optical amplifier gain is too large) is also investigated.

  12. Inner-shell magnetic dipole transition in Tm atoms: A candidate for optical lattice clocks

    NASA Astrophysics Data System (ADS)

    Sukachev, D.; Fedorov, S.; Tolstikhina, I.; Tregubov, D.; Kalganova, E.; Vishnyakova, G.; Golovizin, A.; Kolachevsky, N.; Khabarova, K.; Sorokin, V.

    2016-08-01

    We consider a narrow magneto-dipole transition in the 169Tm atom at the wavelength of 1.14 μ m as a candidate for a two-dimensional-optical lattice clock. Calculating dynamic polarizabilities of the two clock levels [Xe] 4 f136 s2(J =7 /2 ) and [Xe] 4 f136 s2(J =5 /2 ) in the spectral range from 250 to 1200 nm, we find a "magic" wavelength for the optical lattice at 807 nm. Frequency shifts due to black-body radiation (BBR), the van der Waals interaction, the magnetic dipole-dipole interaction, and other effects which can perturb the transition frequency are calculated. The transition at 1.14 μ m demonstrates low sensitivity to the BBR shift corresponding to 8 ×10-17 in fractional units at room temperature which makes it an interesting candidate for high-performance optical clocks. The total estimated frequency uncertainty is less than 5 ×10-18 in fractional units. By direct excitation of the 1.14 μ m transition in Tm atoms loaded into an optical dipole trap, we set the lower limit for the lifetime of the upper clock level [Xe] 4 f136 s2(J =5 /2 ) of 112 ms which corresponds to a natural spectral linewidth narrower than 1.4 Hz. The polarizability of the Tm ground state was measured by the excitation of parametric resonances in the optical dipole trap at 532 nm.

  13. A quantum gas microscope for detecting single atoms in a Hubbard-regime optical lattice.

    PubMed

    Bakr, Waseem S; Gillen, Jonathon I; Peng, Amy; Fölling, Simon; Greiner, Markus

    2009-11-05

    Recent years have seen tremendous progress in creating complex atomic many-body quantum systems. One approach is to use macroscopic, effectively thermodynamic ensembles of ultracold atoms to create quantum gases and strongly correlated states of matter, and to analyse the bulk properties of the ensemble. For example, bosonic and fermionic atoms in a Hubbard-regime optical lattice can be used for quantum simulations of solid-state models. The opposite approach is to build up microscopic quantum systems atom-by-atom, with complete control over all degrees of freedom. The atoms or ions act as qubits and allow the realization of quantum gates, with the goal of creating highly controllable quantum information systems. Until now, the macroscopic and microscopic strategies have been fairly disconnected. Here we present a quantum gas 'microscope' that bridges the two approaches, realizing a system in which atoms of a macroscopic ensemble are detected individually and a complete set of degrees of freedom for each of them is determined through preparation and measurement. By implementing a high-resolution optical imaging system, single atoms are detected with near-unity fidelity on individual sites of a Hubbard-regime optical lattice. The lattice itself is generated by projecting a holographic mask through the imaging system. It has an arbitrary geometry, chosen to support both strong tunnel coupling between lattice sites and strong on-site confinement. Our approach can be used to directly detect strongly correlated states of matter; in the context of condensed matter simulation, this corresponds to the detection of individual electrons in the simulated crystal. Also, the quantum gas microscope may enable addressing and read-out of large-scale quantum information systems based on ultracold atoms.

  14. Creating topological interfaces and detecting chiral edge modes in a two-dimensional optical lattice

    NASA Astrophysics Data System (ADS)

    Goldman, N.; Jotzu, G.; Messer, M.; Görg, F.; Desbuquois, R.; Esslinger, T.

    2016-10-01

    We propose a general scheme to create chiral topological edge modes within the bulk of two-dimensional engineered quantum systems. Our method is based on the implementation of topological interfaces, designed within the bulk of the system, where topologically protected edge modes localize and freely propagate in a unidirectional manner. This scheme is illustrated through an optical-lattice realization of the Haldane model for cold atoms [G. Jotzu et al., Nature (London) 515, 237 (2014), 10.1038/nature13915], where an additional spatially varying lattice potential induces distinct topological phases in separated regions of space. We present two realistic experimental configurations, which lead to linear and radial-symmetric topological interfaces, which both allow one to significantly reduce the effects of external confinement on topological edge properties. Furthermore, the versatility of our method opens the possibility of tuning the position, the localization length, and the chirality of the edge modes, through simple adjustments of the lattice potentials. In order to demonstrate the unique detectability offered by engineered interfaces, we numerically investigate the time evolution of wave packets, indicating how topological transport unambiguously manifests itself within the lattice. Finally, we analyze the effects of disorder on the dynamics of chiral and nonchiral states present in the system. Interestingly, engineered disorder is shown to provide a powerful tool for the detection of topological edge modes in cold-atom setups.

  15. Optical induction of Bessel-like lattices in methyl-red doped liquid crystal cells

    NASA Astrophysics Data System (ADS)

    Mantashyan, Paytsar; Drampyan, Rafael; Beeckman, Jeroen; Willekens, Oliver; Neyts, Kristiaan

    2015-03-01

    The optical induction of annular photonic lattices by a traveling Bessel beam has been investigated in Methyl-red (MR) doped nematic liquid crystal (LC). Non-diffracting Bessel beams were formed by an axicon. The induced Bessel-like lattice had a ~15 μm period in the radial direction. The lattice was tested by measuring the forward diffracted power of the recording Bessel beam. The dependency on the angle between the polarization of the laser beam and the director of the LC and on the axial position of the LC cell had been investigated. A diffraction efficiency of 14% had been obtained. Investigations have been performed for different MR dye doping concentrations. An erasure time of the lattice of 60 s has been determined by a 532 nm probe Gaussian beam of 2 mW in a LC cell with MR dye concentration of 1.15 wt%. The induced periodically varying refractive index in the LC medium is analogous to microstructured fibers and allows the study of light localization and soliton behavior in highly nonlinear waveguide arrays.

  16. Near ground state Raman sideband cooling of an ion in a hybrid radiofrequency-optical lattice trap

    NASA Astrophysics Data System (ADS)

    Bylinskii, Alexei; Karpa, Leon; Gangloff, Dorian; Cetina, Marko; Vuletic, Vladan

    2013-05-01

    We achieve near ground state cooling of an ion in a hybrid trap formed by a two-dimensional radio-frequency Paul trap and an optical lattice produced by a cavity in the axial dimension. We drive far-detuned lattice-assisted Raman transitions on the red vibrational sideband between the Zeeman sublevels of the 2S1/2 ground level of 174Yb+. The cooling cycle is completed by a close-detuned spontaneous Raman transition. Efficient Cooling in all three dimensions is achieved this way. Furthermore, spatially dependent AC Stark shifts induced by the lattice allow us to measure axial temperature via ion fluorescence, and we estimate the population of the lattice vibrational ground state to be above 50%. This work is an important step towards quantum information and quantum simulations with ions in hybrid traps and optical lattices. Army Research Office, National Science Foundation, National Science and Engineering Research Council of Canada, Alexander von Humboldt Foundation.

  17. Theoretical description of two ultracold atoms in finite three-dimensional optical lattices using realistic interatomic interaction potentials

    SciTech Connect

    Grishkevich, Sergey; Sala, Simon; Saenz, Alejandro

    2011-12-15

    A theoretical approach is described for an exact numerical treatment of a pair of ultracold atoms interacting via a central potential and that are trapped in a finite three-dimensional optical lattice. The coupling of center-of-mass and relative-motion coordinates is treated using an exact diagonalization (configuration-interaction) approach. The orthorhombic symmetry of an optical lattice with three different but orthogonal lattice vectors is explicitly considered as is the fermionic or bosonic symmetry in the case of indistinguishable particles.

  18. Coherent driving and freezing of bosonic matter wave in an optical Lieb lattice

    PubMed Central

    Taie, Shintaro; Ozawa, Hideki; Ichinose, Tomohiro; Nishio, Takuei; Nakajima, Shuta; Takahashi, Yoshiro

    2015-01-01

    Although kinetic energy of a massive particle generally has quadratic dependence on its momentum, a flat, dispersionless energy band is realized in crystals with specific lattice structures. Such macroscopic degeneracy causes the emergence of localized eigenstates and has been a key concept in the context of itinerant ferromagnetism. We report the realization of a “Lieb lattice” configuration with an optical lattice, which has a flat energy band as the first excited state. Our optical lattice potential has various degrees of freedom in its manipulation, which enables coherent transfer of a Bose-Einstein condensate into the flat band. In addition to measuring lifetime of the flat band population for different tight-binding parameters, we investigate the inter-sublattice dynamics of the system by projecting the sublattice population onto the band population. This measurement clearly shows the formation of the localized state with the specific sublattice decoupled in the flat band, and even detects the presence of flat-band breaking perturbations, resulting in the delocalization. Our results will open up the possibilities of exploring the physics of flat bands with a highly controllable quantum system. PMID:26665167

  19. Optically induced lattice dynamics probed with ultrafast x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Lee, H. J.; Workman, J.; Wark, J. S.; Averitt, R. D.; Taylor, A. J.; Roberts, J.; McCulloch, Q.; Hof, D. E.; Hur, N.; Cheong, S.-W.; Funk, D. J.

    2008-04-01

    We have studied the picosecond lattice dynamics of optically pumped hexagonal LuMnO3 by using ultrafast x-ray diffraction. The results show a shift and broadening of the diffraction curve due to the stimulated lattice expansion. To understand the transient response of the lattice, the measured time- and angle-resolved diffraction curves are compared to a theoretical calculation based on the dynamical diffraction theory of coherent phonon propagation modified for the hexagonal crystal structure of LuMnO3 . Our simulations reveal that a large coupling coefficient (c13) between the a-b plane and the c axis is required to fit the data. Though we interpret the transient response within the framework of thermal coherent phonons, we do not exclude the possibility of strong nonthermal coupling of the electronic excitation to the atomic framework. We compare this result to our previous coherent phonon studies of LuMnO3 in which we used optical pump-probe spectroscopy.

  20. Algorithm of Shaping Multiple-beam Braggs Acousto-optic Diffraction Laser Field Into 1D and 2D Patterns

    NASA Astrophysics Data System (ADS)

    Zakharchenko, S.; Baturin, A.

    2015-09-01

    Algorithm of solving a direct problem of acousto-optic interaction between laser emission and acoustic signal consisting of a set of equidistant frequency components is proposed. An infinite system of coupled wave differential equations is reduced to eigenvalue problem. The contribution of the higher rediffraction orders is analyzed separately. Inverse problem of finding an optimal set of equidistant frequency components of a driving acoustic signal to form the objective diffraction pattern is also considered and a few optimization approaches are analyzed. A naïve heuristic method of splitting 2D pattern into subframes, each suitable for simultaneous projection by two acousto-optical deflectors driven by multifrequency composite signal, is developed.

  1. Titanium trisulfide (TiS3): a 2D semiconductor with quasi-1D optical and electronic properties

    PubMed Central

    Island, Joshua O.; Biele, Robert; Barawi, Mariam; Clamagirand, José M.; Ares, José R.; Sánchez, Carlos; van der Zant, Herre S. J.; Ferrer, Isabel J.; D’Agosta, Roberto; Castellanos-Gomez, Andres

    2016-01-01

    We present characterizations of few-layer titanium trisulfide (TiS3) flakes which, due to their reduced in-plane structural symmetry, display strong anisotropy in their electrical and optical properties. Exfoliated few-layer flakes show marked anisotropy of their in-plane mobilities reaching ratios as high as 7.6 at low temperatures. Based on the preferential growth axis of TiS3 nanoribbons, we develop a simple method to identify the in-plane crystalline axes of exfoliated few-layer flakes through angle resolved polarization Raman spectroscopy. Optical transmission measurements show that TiS3 flakes display strong linear dichroism with a magnitude (transmission ratios up to 30) much greater than that observed for other anisotropic two-dimensional (2D) materials. Finally, we calculate the absorption and transmittance spectra of TiS3 in the random-phase-approximation (RPA) and find that the calculations are in qualitative agreement with the observed experimental optical transmittance. PMID:26931161

  2. Titanium trisulfide (TiS3): a 2D semiconductor with quasi-1D optical and electronic properties

    NASA Astrophysics Data System (ADS)

    Island, Joshua O.; Biele, Robert; Barawi, Mariam; Clamagirand, José M.; Ares, José R.; Sánchez, Carlos; van der Zant, Herre S. J.; Ferrer, Isabel J.; D’Agosta, Roberto; Castellanos-Gomez, Andres

    2016-03-01

    We present characterizations of few-layer titanium trisulfide (TiS3) flakes which, due to their reduced in-plane structural symmetry, display strong anisotropy in their electrical and optical properties. Exfoliated few-layer flakes show marked anisotropy of their in-plane mobilities reaching ratios as high as 7.6 at low temperatures. Based on the preferential growth axis of TiS3 nanoribbons, we develop a simple method to identify the in-plane crystalline axes of exfoliated few-layer flakes through angle resolved polarization Raman spectroscopy. Optical transmission measurements show that TiS3 flakes display strong linear dichroism with a magnitude (transmission ratios up to 30) much greater than that observed for other anisotropic two-dimensional (2D) materials. Finally, we calculate the absorption and transmittance spectra of TiS3 in the random-phase-approximation (RPA) and find that the calculations are in qualitative agreement with the observed experimental optical transmittance.

  3. Measuring horizontal atmospheric turbulence at ground level from optical turbulence generator (OTG) using a 1D sensor

    NASA Astrophysics Data System (ADS)

    Tíjaro Rojas, Omar J.; Torres Moreno, Yezid; Rhodes, William T.

    2017-06-01

    Different theories including Kolmogorov have been valid to explain and model physic phenomenal like vertical atmospheric turbulence. In horizontal path, we still have many questions, due to weather problems and consequences that it generates. To emulate some conditions of environment, we built an Optical Turbulence Generator (OTG) having spatial, humidity and temperature, measurements that were captured in the same time from optical synchronization. This development was made using digital modules as ADC (Analog to Digital Converters) and communications protocol as SPI. We all made from microcontrollers. On the other hand, to measure optical signal, we used a photomultiplier tube (PMT) where captured the intensity of fringes that shifted with a known frequency. Outcomes show temporal shift and phase drive from dependent samples (in time domain) that correspond with frozen turbulence given by Taylor theory. Parameters studied were C2n, scintillation and inner scale in temporal patterns and analysis of their relationship with the physical associated variables. These patterns were taken from Young Interferometer in laboratory room scale. In the future, we hope with these studies, we will can implement an experiment to characterize atmospheric turbulence in a long distance, placed in the equatorial weather zone.

  4. Titanium trisulfide (TiS3): a 2D semiconductor with quasi-1D optical and electronic properties.

    PubMed

    Island, Joshua O; Biele, Robert; Barawi, Mariam; Clamagirand, José M; Ares, José R; Sánchez, Carlos; van der Zant, Herre S J; Ferrer, Isabel J; D'Agosta, Roberto; Castellanos-Gomez, Andres

    2016-03-02

    We present characterizations of few-layer titanium trisulfide (TiS3) flakes which, due to their reduced in-plane structural symmetry, display strong anisotropy in their electrical and optical properties. Exfoliated few-layer flakes show marked anisotropy of their in-plane mobilities reaching ratios as high as 7.6 at low temperatures. Based on the preferential growth axis of TiS3 nanoribbons, we develop a simple method to identify the in-plane crystalline axes of exfoliated few-layer flakes through angle resolved polarization Raman spectroscopy. Optical transmission measurements show that TiS3 flakes display strong linear dichroism with a magnitude (transmission ratios up to 30) much greater than that observed for other anisotropic two-dimensional (2D) materials. Finally, we calculate the absorption and transmittance spectra of TiS3 in the random-phase-approximation (RPA) and find that the calculations are in qualitative agreement with the observed experimental optical transmittance.

  5. {pi} Phases in Balanced Fermionic Superfluids on Spin-Dependent Optical Lattices

    SciTech Connect

    Zapata, I.; Wunsch, B.; Zinner, N. T.; Demler, E.

    2010-08-27

    We study a balanced two-component system of ultracold fermions in one dimension with attractive interactions and subject to a spin-dependent optical lattice potential of opposite sign for the two components. We find states with different types of modulated pairing order parameters which are conceptually similar to {pi} phases discussed for superconductor-ferromagnet heterostructures. Increasing the lattice depth induces sharp transitions between states of different parity. While the origin of the order parameter oscillations is similar to the Fulde-Ferrel-Larkin-Ovchinnikov phase for paired states with spin imbalance, the current system is intrinsically stable to phase separation. We discuss experimental requirements for creating and probing these novel phases.

  6. Gap solitons in the nonlinear fractional Schrödinger equation with an optical lattice.

    PubMed

    Huang, Changming; Dong, Liangwei

    2016-12-15

    We predict the existence of gap solitons in the nonlinear fractional Schrödinger equation (NLFSE) with an imprinted optically harmonic lattice. Symmetric/antisymmetric nonlinear localized modes bifurcate from the lower/upper edge of the first/second band in defocusing/focusing Kerr media. A unique feature we revealed is that, in focusing Kerr media, stable solitons appear in the finite bandgaps with the decrease of the Lévy index, which is in sharp contrast to the standard NLSE with a focusing nonlinearity. Nonlinear bound states composed by in-phase and out-of-phase soliton units supported by the NLFSE are also uncovered. Our work may pave the way for the study of spatial lattice solitons in fractional dimensions.

  7. Proposed formation and dynamical signature of a chiral Bose liquid in an optical lattice.

    PubMed

    Li, Xiaopeng; Paramekanti, Arun; Hemmerich, Andreas; Liu, W Vincent

    2014-01-01

    Recent experiments on p-orbital atomic bosons have suggested the emergence of a spectacular ultracold superfluid with staggered orbital currents in optical lattices. This raises fundamental questions concerning the effects of thermal fluctuations as well as possible ways of directly observing such chiral order. Here we show via Monte Carlo simulations that thermal fluctuations destroy this superfluid in an unexpected two-step process, unveiling an intermediate normal phase with spontaneously broken time-reversal symmetry, dubbed a 'chiral Bose liquid'. For integer fillings (n≥2) in the chiral Mott regime, thermal fluctuations are captured by an effective orbital Ising model, and Onsager's powerful exact solution is adopted to determine the transition from this intermediate liquid to the para-orbital normal phase at high temperature. A lattice quench is designed to convert the staggered angular momentum, previously thought by experts difficult to directly probe, into coherent orbital oscillations, providing a time-resolved dynamical signature of chiral order.

  8. From Berry's Phase to Wilson Lines in a Honeycomb Optical Lattice

    NASA Astrophysics Data System (ADS)

    Schleier-Smith, Monika

    I will report on methods for fully characterizing the topology and geometry of Bloch bands in optical lattices. Using a Bose-Einstein condensate as a momentum-resolved probe, we study a paradigmatic model system, the honeycomb lattice. Its salient features are two Dirac points, each producing a half-quantum of Berry flux similar to the magnetic flux of an infinitesimally narrow solenoid. We have detected this singular Berry flux by forming an Aharonov-Bohm-type interferometer in momentum space. Our technique is broadly applicable to mapping out the Berry curvature or directly measuring the Chern number of a single band. I will furthermore show how interband dynamics can reveal the matrix-valued Wilson line, the generalization of Berry's phase to the multi-band setting. In the simple case where the Wilson line is path-independent and Abelian, it serves as a powerful tool for tomographic reconstruction of the band eigenstates.

  9. Roton-maxon excitation spectrum of Bose condensates in a shaken optical lattice

    NASA Astrophysics Data System (ADS)

    Ha, Li-Chung; Clark, Logan W.; Parker, Colin V.; Xu, Chen-Yu; Chin, Cheng

    2015-05-01

    We present a resonant lattice shaking technique for engineering the dispersion of a cesium Bose condensate. Through phase modulating an optical lattice at a frequency near the band splitting, the dispersion of the condensate can evolve from quadratic to quartic and finally into a double-well structure. We observe effective ferromagnetism in the double-well regime, and atoms form domains within one well in momentum space. We study the elementary excitations of this system by implementing projection-based Bragg spectroscopy and find a roton-maxon feature in the excitation spectrum in agreement with a Bogoliubov calculation. Consistent with Landau's prediction, we observe a suppressed superfluid critical velocity due to the existence of the roton. We will introduce more precise characterizations of the dispersion in an effort to pinpoint the critical point at which the dispersion is purely quartic, and study the dynamics of particles in that case. This work is supported by NSF, ARO and Chicago MRSEC.

  10. Observation of Nonlinear Looped Band Structure of Bose-Einstein condensates in an optical lattice

    NASA Astrophysics Data System (ADS)

    Goldschmidt, Elizabeth; Koller, Silvio; Brown, Roger; Wyllie, Robert; Wilson, Ryan; Porto, Trey

    2016-05-01

    We study experimentally the stability of excited, interacting states of bosons in a double-well optical lattice in regimes where the nonlinear interactions are expected to induce ``swallow-tail'' looped band structure. By carefully preparing different initial coherent states and observing their subsequent decay, we observe distinct decay rates, which provide direct evidence for multi-valued band structure. The double well lattice both stabilizes the looped band structure and allows for dynamic preparation of different initial states, including states within the loop structure. We confirm our state preparation procedure with dynamic Gross-Pitaevskii calculations. The excited loop states are found to be more stable than dynamically unstable ground states, but decay faster than expected based on a mean-field stability calculation, indicating the importance of correlations beyond a mean-field description. Now at Georgia Tech Research Institute.

  11. Frequency Ratio of (199)Hg and (87)Sr Optical Lattice Clocks beyond the SI Limit.

    PubMed

    Yamanaka, Kazuhiro; Ohmae, Noriaki; Ushijima, Ichiro; Takamoto, Masao; Katori, Hidetoshi

    2015-06-12

    We report on a frequency ratio measurement of a (199)Hg-based optical lattice clock referencing a (87)Sr-based clock. Evaluations of lattice light shift, including atomic-motion-dependent shift, enable us to achieve a total systematic uncertainty of 7.2×10(-17) for the Hg clock. The frequency ratio is measured to be νHg/νSr=2.629 314 209 898 909 60(22) with a fractional uncertainty of 8.4×10(-17), which is smaller than the uncertainty of the realization of the International System of Units (SI) second, i.e., the SI limit.

  12. Beam dynamics in disordered P T -symmetric optical lattices based on eigenstate analyses

    NASA Astrophysics Data System (ADS)

    Yao, Xiankun; Liu, Xueming

    2017-03-01

    Wave functions will experience a localization process when evolving in disordered lattices. Here, we have demonstrated the effects of disordered P T -symmetric potentials on wave-function characteristics in optics based on eigenstate analyses. In weak-disorder cases, by using the tight-binding approximation method, a conclusion is obtained that the increasing of the imaginary part of potential can enhance the diffraction, while the increasing disorder will block the diffraction and lead to localization. In the general case, band theory is used for band-structure analysis of three bands. We find that the disorder has a smaller effect on the higher-order band, which is proved by the beam evolutions. Our work may be instructive for realizing beam path control by manipulating the strengths of disorder and gain and/or loss of lattice.

  13. Entanglement and the ground state of fermions trapped in optical lattices

    NASA Astrophysics Data System (ADS)

    Silva-Valencia, J.; Franco, R.; Figueira, M. S.

    2009-10-01

    Using White's density matrix renormalization group technique we calculate entanglement of fermions confined in a one-dimensional trap with an underlying lattice. The system is modeled using a repulsive Hubbard model plus a quadratic potential. Due to the confining potential, metallic and Mott-insulating domains coexist in the system. The entanglement is measured by the on-site entropy and the block entropy, and these quantities are calculated as a function of the local repulsion and the curvature of the trap. We found that local entropy decreases with the curvature for a fixed on-site repulsion. As a function of the on-site repulsion the local entropy first increases and then diminishes. Our most important goal is to show that local and block entropy are useful tools for characterization of the ground states of fermions trapped in optical lattices.

  14. Experimental Realization of Strong Effective Magnetic Fields in an Optical Lattice

    SciTech Connect

    Aidelsburger, M.; Atala, M.; Trotzky, S.; Chen, Y.-A.; Bloch, I.; Nascimbene, S.

    2011-12-16

    We use Raman-assisted tunneling in an optical superlattice to generate large tunable effective magnetic fields for ultracold atoms. When hopping in the lattice, the accumulated phase shift by an atom is equivalent to the Aharonov-Bohm phase of a charged particle exposed to a staggered magnetic field of large magnitude, on the order of 1 flux quantum per plaquette. We study the ground state of this system and observe that the frustration induced by the magnetic field can lead to a degenerate ground state for noninteracting particles. We provide a measurement of the local phase acquired from Raman-induced tunneling, demonstrating time-reversal symmetry breaking of the underlying Hamiltonian. Furthermore, the quantum cyclotron orbit of single atoms in the lattice exposed to the magnetic field is directly revealed.

  15. Shaken not stirred: creating exotic angular momentum states by shaking an optical lattice

    NASA Astrophysics Data System (ADS)

    Kiely, Anthony; Benseny, Albert; Busch, Thomas; Ruschhaupt, Andreas

    2016-11-01

    We propose a method to create higher orbital states of ultracold atoms in the Mott regime of an optical lattice. This is done by periodically modulating the position of the trap minima (known as shaking) and controlling the interference term of the lasers creating the lattice. These methods are combined with techniques of shortcuts to adiabaticity. As an example of this, we show specifically how to create an anti-ferromagnetic type ordering of angular momentum states of atoms. The specific pulse sequences are designed using Lewis-Riesenfeld invariants and a four-level model for each well. The results are compared with numerical simulations of the full Schrödinger equation.

  16. Topological Properties of Ultracold Bosons in One-Dimensional Quasiperiodic Optical Lattice

    NASA Astrophysics Data System (ADS)

    Matsuda, Fuyuki; Tezuka, Masaki; Kawakami, Norio

    2014-08-01

    We analyze the topological properties of the one-dimensional Bose-Hubbard model with a quasiperiodic superlattice potential. This system can be realized in interacting ultracold bosons in an optical lattice in the presence of an incommensurate superlattice potential. We first analyze the quasiperiodic superlattice formed by the cosine function, which we call the Harper-like Bose-Hubbard model. We compute the Chern number and observe gap-closing behavior as the interaction strength U is changed. Also, we discuss the bulk-edge correspondence in our system. Furthermore, we explore the phase diagram as a function of U and a continuous deformation parameter β between the Harper-like model and another important quasiperiodic lattice, the Fibonacci model. We numerically confirm that the incommensurate charge density wave (ICDW) phase is topologically nontrivial and that it is topologically equivalent in the whole ICDW region.

  17. Interferometric Approach to Measuring Band Topology in 2D Optical Lattices

    NASA Astrophysics Data System (ADS)

    Abanin, Dmitry A.; Kitagawa, Takuya; Bloch, Immanuel; Demler, Eugene

    2013-04-01

    Recently, optical lattices with nonzero Berry’s phases of Bloch bands have been realized. New approaches for measuring Berry’s phases and topological properties of bands with experimental tools appropriate for ultracold atoms need to be developed. In this Letter, we propose an interferometric method for measuring Berry’s phases of two-dimensional Bloch bands. The key idea is to use a combination of Ramsey interference and Bloch oscillations to measure Zak phases, i.e., Berry’s phases for closed trajectories corresponding to reciprocal lattice vectors. We demonstrate that this technique can be used to measure the Berry curvature of Bloch bands, the π Berry’s phase of Dirac points, and the first Chern number of topological bands. We discuss several experimentally feasible realizations of this technique, which make it robust against low-frequency magnetic noise.

  18. Thermometry of Cold Atoms in Optical Lattices via Artificial Gauge Fields

    NASA Astrophysics Data System (ADS)

    Roscilde, Tommaso

    2014-03-01

    Artificial gauge fields are a unique way of manipulating the motional state of cold atoms. Here we propose the use (practical or conceptual) of artificial gauge fields—obtained, e.g., experimentally via lattice shaking or conceptually via a Galilean transformation—to perform primary noise thermometry of cold atoms in optical lattices, not requiring any form of prior calibration. The proposed thermometric scheme relies on fundamental fluctuation-dissipation relations, connecting the global response to the variation of the applied gauge field and the fluctuation of quantities related to the momentum distribution (such as the average kinetic energy or the average current). We demonstrate gauge-field thermometry for several physical situations, including free fermions and interacting bosons. The proposed approach is extremely robust to quantum fluctuations—even in the vicinity of a quantum phase transition—when it relies on the thermal fluctuations of an emerging classical field, associated with the onset of Bose condensation or chiral order.

  19. Flow-induced charge modulation in superfluid atomic fermions loaded into an optical kagome lattice.

    PubMed

    Yamamoto, Daisuke; Sato, Chika; Nikuni, Tetsuro; Tsuchiya, Shunji

    2013-04-05

    We study the superfluid state of atomic fermions in a tunable optical kagome lattice motivated by recent experiments. We show that the imposed superflow induces spatial modulations in the density and order parameter of the pair condensate and leads to a charge modulated superfluid state analogous to a supersolid state. The spatial modulations in the superfluid emerge due to the geometric effect of the kagome lattice that introduces anisotropy in hopping amplitudes of fermion pairs in the presence of superflow. We also study superflow instabilities and find that the critical current limited by the dynamical instability is quite enhanced due to the large density of states associated with the flatband. The charge modulated superfluid state can sustain high temperatures close to the transition temperature that is also enhanced due to the flatband and is therefore realizable in experiments.

  20. 2D Superexchange-mediated magnetization dynamics in an optical lattice

    NASA Astrophysics Data System (ADS)

    Goldschmidt, Elizabeth; Brown, Roger; Wyllie, Robert; Koller, Silvio; Foss-Feig, Michael; Porto, Trey

    2015-05-01

    The interplay of magnetic exchange interactions and tunneling underlies many complex quantum phenomena observed in real materials. We study nonequilibrium magnetization dynamics in an extended 2D system by loading effective spin-1/2 bosons into a spin-dependent optical lattice, and we use the lattice to separately control the resonance conditions for tunneling and superexchange. After preparing a nonequilibrium antiferromagnetically ordered state, we observe relaxation dynamics governed by two well-separated rates, which scale with the underlying Hamiltonian parameters associated with superexchange and tunneling. Remarkably, with tunneling off-resonantly suppressed, we are able to observe superexchange-dominated dynamics over two orders of magnitude in magnetic coupling strength, despite the presence of vacancies. In this regime, the measured timescales are in agreement with simple theoretical estimates, but the detailed dynamics of this 2D, strongly-correlated, and far-from-equilibrium quantum system remain out of reach of current computational techniques. Now at Georgia Tech Research Institute.

  1. A study of optical reflectance and localization modes of 1-D Fibonacci photonic quasicrystals using different graded dielectric materials

    NASA Astrophysics Data System (ADS)

    Singh, Bipin K.; Pandey, Praveen C.

    2014-06-01

    In this paper, we present an analytical study on the reflection properties of light through one-dimensional (1-D) quasi-periodic multilayer structures. The considered structures are as follows: F7, F8, F9, (F2)10, (F3)10 and some combinations such as: [(F2)10 (F7) (F2)10], [(F2)10 (F8) (F2)10], [(F3)10 (F7) (F3)10], [(F3)10 (F8) (F3)10], [(F2)10(F3)10], [(F2)10 (F7) (F3)10] and [(F2)10 (F8) (F3)10], where (Fj)n represents n period of the Fibonacci sequence of jth generation. These multilayer structures are considered of two types of layers. One type of layer is considered of graded material like normal, linear or exponential graded material, and the second type of layer is considered of constant refractive index material. Transfer matrix method is utilized to calculate the reflection spectra and localization modes of such structures in the frequency range 150-450 THz. This work would provide the basis of understanding of the effect of graded materials on the reflection and localization modes in Fibonacci photonic quasicrystal structures and obtained spectra can be used in the recognition of grading of materials. The considered heterostructures provide the broad reflection band and some localization modes in the calculated region.

  2. Demonstration of a fast-reconfigurable silicon CMOS optical lattice filter.

    PubMed

    Ibrahim, Salah; Fontaine, Nicolas K; Djordjevic, Stevan S; Guan, Binbin; Su, Tiehui; Cheung, Stanley; Scott, Ryan P; Pomerene, Andrew T; Seaford, Liberty L; Hill, Craig M; Danziger, Steve; Ding, Zhi; Okamoto, K; Yoo, S J B

    2011-07-04

    We demonstrate a fully-reconfigurable fourth-order optical lattice filter built by cascading identical unit cells consisting of a Mach-Zehnder interferometer (MZI) and a ring resonator. The filter is fabricated using a commercial silicon complementary metal oxide semiconductor (CMOS) process and reconfigured by current injection into p-i-n diodes with a reconfiguration time of less than 10 ns. The experimental results show full control over the single unit cell pole and zero, switching the unit cell transfer function between a notch filter and a bandpass filter, narrowing the notch width down to 400 MHz, and tuning the center wavelength over the full free spectral range (FSR) of 10 GHz. Theoretical and experimental results show tuning dynamics and associated optical losses in the reconfigurable filters. The full-control of each of the four cascaded single unit cells resulted in demonstrations of a number of fourth-order transfer functions. The multimedia experimental data show live tuning and reconfiguration of optical lattice filters.

  3. LBNE lattice & optics for proton extraction at MI-10 and transport to a target above grade

    SciTech Connect

    Johnstone, John A.; /Fermilab

    2011-09-01

    For the Long Baseline Neutrino Experiment (LBNE) at Fermilab 120 GeV/c protons will be transported from the Main Injector (MI) to an on-site production target. The lattice design and optics discussed here has the beam extracted vertically upwards from MI-10 and the keeps the majority of the line at an elevation above the glacial till/rock interface and terminates on a target at 10 ft above grade. The LBNE beamline discussed here is a modular optics design comprised of 3 distinct lattice configurations, including the specialized MI {yields} LBNE matching section and Final Focus. The remainder of the line is defined by six FODO cells, in which the length and phase advance are chosen specifically such that beam size does not exceed that of the MI while also making the most efficient use of space for achromatic insertions. Dispersion generated by variations in the beam trajectory are corrected locally and can not bleed out to corrupt the optics elsewhere in the line. Aperture studies indicate that the line should be able to transport the worst quality beam that the Main Injector might provide. New IDS dipole correctors located at every focusing center provide high-quality orbit control and further ensure that LBNE meets the stringent requirements for environmental protection.

  4. Transportable Optical Lattice Clock with 7 ×10-17 Uncertainty

    NASA Astrophysics Data System (ADS)

    Koller, S. B.; Grotti, J.; Vogt, St.; Al-Masoudi, A.; Dörscher, S.; Häfner, S.; Sterr, U.; Lisdat, Ch.

    2017-02-01

    We present a transportable optical clock (TOC) with Sr 87 . Its complete characterization against a stationary lattice clock resulted in a systematic uncertainty of 7.4 ×10-17, which is currently limited by the statistics of the determination of the residual lattice light shift, and an instability of 1.3 ×10-15/√{τ } with an averaging time τ in seconds. Measurements confirm that the systematic uncertainty can be reduced to below the design goal of 1 ×10-17. To our knowledge, these are the best uncertainties and instabilities reported for any transportable clock to date. For autonomous operation, the TOC has been installed in an air-conditioned car trailer. It is suitable for chronometric leveling with submeter resolution as well as for intercontinental cross-linking of optical clocks, which is essential for a redefinition of the International System of Units (SI) second. In addition, the TOC will be used for high precision experiments for fundamental science that are commonly tied to precise frequency measurements and its development is an important step to space-borne optical clocks.

  5. Transportable Optical Lattice Clock with 7×10^{-17} Uncertainty.

    PubMed

    Koller, S B; Grotti, J; Vogt, St; Al-Masoudi, A; Dörscher, S; Häfner, S; Sterr, U; Lisdat, Ch

    2017-02-17

    We present a transportable optical clock (TOC) with ^{87}Sr. Its complete characterization against a stationary lattice clock resulted in a systematic uncertainty of 7.4×10^{-17}, which is currently limited by the statistics of the determination of the residual lattice light shift, and an instability of 1.3×10^{-15}/sqrt[τ] with an averaging time τ in seconds. Measurements confirm that the systematic uncertainty can be reduced to below the design goal of 1×10^{-17}. To our knowledge, these are the best uncertainties and instabilities reported for any transportable clock to date. For autonomous operation, the TOC has been installed in an air-conditioned car trailer. It is suitable for chronometric leveling with submeter resolution as well as for intercontinental cross-linking of optical clocks, which is essential for a redefinition of the International System of Units (SI) second. In addition, the TOC will be used for high precision experiments for fundamental science that are commonly tied to precise frequency measurements and its development is an important step to space-borne optical clocks.

  6. Exploring topological double-Weyl semimetals with cold atoms in optical lattices

    NASA Astrophysics Data System (ADS)

    Mai, Xue-Ying; Zhang, Dan-Wei; Li, Zhi; Zhu, Shi-Liang

    2017-06-01

    We explore the topological properties of double-Weyl semimetals with cold atoms in optical lattices. We first propose a tight-binding model of simulating the double-Weyl semimetal with a pair of double-Weyl points by engineering the atomic hopping in a three-dimensional optical lattice. We show that the double-Weyl points with topological charges of ±2 behave as the sink and source of Berry flux in momentum space connecting by two Fermi arcs and they are stabilized by the C4 h point-group symmetry. By applying a realizable C4 breaking term, we find that each double-Weyl point splits into two single-Weyl points and obtain rich phase diagrams in the parameter space spanned by the strengths of an effective Zeeman term and the C4 breaking term, which contains a topological and a normal insulating phase and two topological Weyl semimetal phases with eight and four single-Weyl points, apart from the double-Weyl semimetal phase. Furthermore, we demonstrate with numerical simulations that (i) the mimicked double- and single-Weyl points can be detected by measuring the atomic transfer fractions after a Bloch oscillation; (ii) the Chern number of different quantum phases in the phase diagram can be extracted from the center shift of the hybrid Wannier functions, which can be directly measured with time-of-flight imaging; (iii) the band topology of the C4-symmetric Bloch Hamiltonian can be detected simply from measuring the spin polarization at the high-symmetry momentum points with a condensate in the optical lattice. The proposed system would provide a promising platform for elaborating the intrinsic exotic physics of double-Weyl semimetals and the related topological phase transitions.

  7. The regular lattice of optical vortices used for measurement in two angular and one linear degree of freedom

    NASA Astrophysics Data System (ADS)

    Fraczek, Ewa; Rus, Filip; Mroczka, Janusz

    2010-12-01

    In this paper authors present the method for measurement of micro displacements along optical axis of the reflective object. Three separate focused beams are used in those measurements. Those three plane waves are reflected by examined object surface and their interference tends to create regular lattice of the optical vortices. In this paper authors present test results of sensitivity of an actual measurement system.

  8. Dynamics and stability of Bose-Einstein solitons in tilted optical lattices

    SciTech Connect

    Diaz, E.; Dominguez-Adame, F.; Gaul, C.; Lima, R. P. A.; Mueller, C. A.

    2010-05-15

    Bloch oscillations of Bose-Einstein condensates realize sensitive matter-wave interferometers. We investigate the dynamics and stability of bright-soliton wave packets in one-dimensional tilted optical lattices with a modulated mean-field interaction g(t). By means of a time-reversal argument, we prove the stability of Bloch oscillations of breathing solitons that would be quasistatically unstable. Floquet theory shows that these breathing solitons can be more stable against certain experimental perturbations than rigid solitons or even noninteracting wave packets.

  9. Weyl Points in Three-Dimensional Optical Lattices: Synthetic Magnetic Monopoles in Momentum Space.

    PubMed

    Dubček, Tena; Kennedy, Colin J; Lu, Ling; Ketterle, Wolfgang; Soljačić, Marin; Buljan, Hrvoje

    2015-06-05

    We show that a Hamiltonian with Weyl points can be realized for ultracold atoms using laser-assisted tunneling in three-dimensional optical lattices. Weyl points are synthetic magnetic monopoles that exhibit a robust, three-dimensional linear dispersion, identical to the energy-momentum relation for relativistic Weyl fermions, which are not yet discovered in particle physics. Weyl semimetals are a promising new avenue in condensed matter physics due to their unusual properties such as the topologically protected "Fermi arc" surface states. However, experiments on Weyl points are highly elusive. We show that this elusive goal is well within experimental reach with an extension of techniques recently used in ultracold gases.

  10. Zoo of Quantum Phases and Excitations of Cold Bosonic Atoms in Optical Lattices

    SciTech Connect

    Alon, Ofir E.; Streltsov, Alexej I.; Cederbaum, Lorenz S.

    2005-07-15

    Quantum phases and phase transitions of weakly to strongly interacting bosonic atoms in deep to shallow optical lattices are described by a single multiorbital mean-field approach in real space. For weakly interacting bosons in one dimension, the critical value of the superfluid to Mott insulator (MI) transition found is in excellent agreement with many-body treatments of the Bose-Hubbard model. For strongly interacting bosons (i) additional MI phases appear, for which two (or more) atoms residing in each site undergo a Tonks-Girardeau-like transition and localize, and (ii) on-site excitation becomes the excitation lowest in energy. Experimental implications are discussed.

  11. Low-Acceleration Instability of a Bose-Einstein Condensate in an Optical Lattice

    NASA Astrophysics Data System (ADS)

    Zheng, Yi; Kos̆Trun, Marijan; Javanainen, Juha

    2004-11-01

    We study a Bose-Einstein condensate in a one-dimensional accelerated optical lattice using the mean-field version of the Bose-Hubbard model. Reminiscent of recent experiments [

    M. Cristiani et al., Opt. Express 12, 4 (2004)OPEXFF1094-408710.1364/OPEX.12.000004
    ], we find a new type of an instability in this system that occurs in the limit when the acceleration is small.

  12. Coherent Addressing of Individual Neutral Atoms in a 3D Optical Lattice.

    PubMed

    Wang, Yang; Zhang, Xianli; Corcovilos, Theodore A; Kumar, Aishwarya; Weiss, David S

    2015-07-24

    We demonstrate arbitrary coherent addressing of individual neutral atoms in a 5×5×5 array formed by an optical lattice. Addressing is accomplished using rapidly reconfigurable crossed laser beams to selectively ac Stark shift target atoms, so that only target atoms are resonant with state-changing microwaves. The effect of these targeted single qubit gates on the quantum information stored in nontargeted atoms is smaller than 3×10^{-3} in state fidelity. This is an important step along the path of converting the scalability promise of neutral atoms into reality.

  13. Quantum Correlations of Two SPIN-1 Particles in the Optical Lattice

    NASA Astrophysics Data System (ADS)

    Shi, Jia-Dong; Wu, Tao; Song, Xue-Ke; Ye, Liu

    2014-01-01

    In this paper, we investigate the dynamical behaviors of quantum correlations witnessed by geometric discord and negativity when two three-level spin-1 atoms exist in the optical lattice. The results show that the GD can detect the critical point K = J at finite temperature associated with the quantum phase transition which separates the superfluid phase from the Mott insulator phase, while the negativity cannot. In addition, the system undergoes an entanglement sudden death (ESD), but the GD always exists, meanwhile, the GD is more robust than negativity against temperature T.

  14. Chaos control of a Bose-Einstein condensate in a moving optical lattice

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiying; Feng, Xiuqin; Yao, Zhihai

    2016-07-01

    Chaos control of a Bose-Einstein condensate (BEC) loaded into a moving optical lattice with attractive interaction is investigated on the basis of Lyapunov stability theory. Three methods are designed to control chaos in BEC. As a controller, a bias constant, periodic force, or wavelet function feedback is added to the BEC system. Numerical simulations reveal that chaotic behavior can be well controlled to achieve periodicity by regulating control parameters. Different periodic orbits are available for different control parameters only if the maximal Lyapunov exponent of the system is negative. The abundant effect of chaotic control is also demonstrated numerically. Chaos control can be realized effectively by using our proposed control strategies.

  15. Chiral phase from three-spin interactions in an optical lattice

    SciTech Connect

    D'Cruz, Christian; Pachos, Jiannis K.

    2005-10-15

    A spin-1/2 chain model that includes three-spin interactions can effectively describe the dynamics of two species of bosons trapped in an optical lattice with a triangular-ladder configuration. A perturbative theoretical approach and numerical study of its ground state is performed that reveals a rich variety of phases and criticalities. We identify phases with periodicity one, two, or three, as well as critical points that belong in the same universality class as the Ising or the three-state Potts model. We establish a range of parameters, corresponding to a large degeneracy present between phases with period 2 and 3, that nests a gapless incommensurate chiral phase.

  16. Optical lattices as a tool to study defect-induced superfluidity

    NASA Astrophysics Data System (ADS)

    Astrakharchik, Grigory E.; Krutitsky, Konstantin V.; Lewenstein, Maciej; Mazzanti, Ferran; Boronat, Jordi

    2017-09-01

    We study the superfluid response, the energetic and structural properties of a one-dimensional ultracold Bose gas in an optical lattice of arbitrary strength. We use the Bose-Fermi mapping in the limit of infinitely large repulsive interaction and the diffusion Monte Carlo method in the case of finite interaction. For slightly incommensurate fillings we find a superfluid behavior, which is discussed in terms of vacancies and interstitials. It is shown that both the excitation spectrum and static structure factor are different for the cases of microscopic and macroscopic fractions of defects. This system provides an extremely well-controlled model for studying defect-induced superfluidity.

  17. Phase boundary of the boson Mott insulator in a rotating optical lattice

    SciTech Connect

    Umucalilar, R. O.; Oktel, M. Oe.

    2007-11-15

    We consider the Bose-Hubbard model in a two-dimensional rotating optical lattice and investigate the consequences of the effective magnetic field created by rotation. Using a Gutzwiller-type variational wave function, we find an analytical expression for the Mott insulator (MI)-superfluid (SF) transition boundary in terms of the maximum eigenvalue of the Hofstadter butterfly. The dependence of phase boundary on the effective magnetic field is complex, reflecting the self-similar properties of the single particle energy spectrum. Finally, we argue that fractional quantum Hall phases exist close to the MI-SF transition boundaries, including MI states with particle densities greater than one.

  18. Trapped Fermi Gases in Rotating Optical Lattices: Realization and Detection of the Topological Hofstadter Insulator

    SciTech Connect

    Umucalilar, R. O.; Oktel, M. Oe.; Zhai Hui

    2008-02-22

    We consider a gas of noninteracting spinless fermions in a rotating optical lattice and calculate the density profile of the gas in an external confinement potential. The density profile exhibits distinct plateaus, which correspond to gaps in the single particle spectrum known as the Hofstadter butterfly. The plateaus result from insulating behavior whenever the Fermi energy lies within a gap. We discuss the necessary conditions to realize the Hofstadter insulator in a cold atom setup and show how the quantized Hall conductance can be measured from density profiles using the Streda formula.

  19. Nonlinear resonant tunneling of Bose-Einstein condensates in tilted optical lattices

    SciTech Connect

    Rapedius, K.; Elsen, C.; Korsch, H. J.; Witthaut, D.; Wimberger, S.

    2010-12-15

    We study the tunneling decay of a Bose-Einstein condensate from tilted optical lattices within the mean-field approximation. We introduce a method to calculate ground and excited resonance eigenstates of the Gross-Pitaevskii equation, based on a grid relaxation procedure with complex absorbing potentials. This algorithm works efficiently in a wide range of parameters where established methods fail. It allows us to study the effects of the nonlinearity in detail in the regime of resonant tunneling, where the decay rate is enhanced by resonant coupling to excited unstable states.

  20. Interaction effects on Wannier functions for bosons in an optical lattice

    NASA Astrophysics Data System (ADS)

    Zhu, Shaoqi; Wu, Biao

    2015-12-01

    We have numerically calculated the single-band Wannier functions for interacting Bose gases in optical lattices with a self-consistent approach. We find that the Wannier functions are broadened by repulsive interaction. The tunneling parameter J and the on-site interaction U computed with the broadened Wannier functions are found to change significantly with the number of atoms per site. Our theory can explain the nonuniform atomic clock shift observed in Campbell et al., Science 313, 649 (2006), 10.1126/science.1130365.