Sample records for single spin control

  1. Control of single spin in Markovian environment

    E-print Network

    Yuan, Haidong

    In this article we study the control of single spin in Markovian environment. Given an initial state, we compute all the possible states to which the spin can be driven at arbitrary time, under the assumption that fast ...

  2. Coherent, Mechanical Control of a Single Electronic Spin Sungkun Hong,,

    E-print Network

    Walsworth, Ronald L.

    Coherent, Mechanical Control of a Single Electronic Spin Sungkun Hong,, Michael S. Grinolds coherent quantum control of a single spin driven by the motion of a mechanical resonator. The motion of a mechanical resonator is magnetically coupled to the electronic spin of a single nitrogen-vacancy center

  3. Coherent Control of a Single Silicon-29 Nuclear Spin Qubit

    E-print Network

    Jarryd J. Pla; Fahd A. Mohiyaddin; Kuan Y. Tan; Juan P. Dehollain; Rajib Rahman; Gerhard Klimeck; David N. Jamieson; Andrew S. Dzurak; Andrea Morello

    2014-08-06

    Magnetic fluctuations caused by the nuclear spins of a host crystal are often the leading source of decoherence for many types of solid-state spin qubit. In group-IV materials, the spin-bearing nuclei are sufficiently rare that it is possible to identify and control individual host nuclear spins. This work presents the first experimental detection and manipulation of a single $^{29}$Si nuclear spin. The quantum non-demolition (QND) single-shot readout of the spin is demonstrated, and a Hahn echo measurement reveals a coherence time of $T_2 = 6.3(7)$ ms - in excellent agreement with bulk experiments. Atomistic modeling combined with extracted experimental parameters provides possible lattice sites for the $^{29}$Si atom under investigation. These results demonstrate that single $^{29}$Si nuclear spins could serve as a valuable resource in a silicon spin-based quantum computer.

  4. Electrical control of single hole spins in nanowire quantum dots

    NASA Astrophysics Data System (ADS)

    Pribiag, V. S.; Nadj-Perge, S.; Frolov, S. M.; van den Berg, J. W. G.; van Weperen, I.; Plissard, S. R.; Bakkers, E. P. A. M.; Kouwenhoven, L. P.

    2013-03-01

    The development of viable quantum computation devices will require the ability to preserve the coherence of quantum bits (qubits). Single electron spins in semiconductor quantum dots are a versatile platform for quantum information processing, but controlling decoherence remains a considerable challenge. Hole spins in III-V semiconductors have unique properties, such as a strong spin-orbit interaction and weak coupling to nuclear spins, and therefore, have the potential for enhanced spin control and longer coherence times. A weaker hyperfine interaction has previously been reported in self-assembled quantum dots using quantum optics techniques, but the development of hole-spin-based electronic devices in conventional III-V heterostructures has been limited by fabrication challenges. Here, we show that gate-tunable hole quantum dots can be formed in InSb nanowires and used to demonstrate Pauli spin blockade and electrical control of single hole spins. The devices are fully tunable between hole and electron quantum dots, which allows the hyperfine interaction strengths, g-factors and spin blockade anisotropies to be compared directly in the two regimes.

  5. Electrically controlling single spin qubits in a continuous microwave field

    E-print Network

    Arne Laucht; Juha T. Muhonen; Fahd A. Mohiyaddin; Rachpon Kalra; Juan P. Dehollain; Solomon Freer; Fay E. Hudson; Menno Veldhorst; Rajib Rahman; Gerhard Klimeck; Kohei M. Itoh; David N. Jamieson; Jeffrey C. McCallum; Andrew S. Dzurak; Andrea Morello

    2015-03-20

    Large-scale quantum computers must be built upon quantum bits that are both highly coherent and locally controllable. We demonstrate the quantum control of the electron and the nuclear spin of a single 31P atom in silicon, using a continuous microwave magnetic field together with nanoscale electrostatic gates. The qubits are tuned into resonance with the microwave field by a local change in electric field, which induces a Stark shift of the qubit energies. This method, known as A-gate control, preserves the excellent coherence times and gate fidelities of isolated spins, and can be extended to arbitrarily many qubits without requiring multiple microwave sources.

  6. High precision quantum control of single donor spins in silicon

    E-print Network

    Rajib Rahman; Cameron J. Wellard; Forrest R. Bradbury; Marta Prada; Jared H. Cole; Gerhard Klimeck; Lloyd C. L. Hollenberg

    2007-05-15

    The Stark shift of the hyperfine coupling constant is investigated for a P donor in Si far below the ionization regime in the presence of interfaces using Tight-binding and Band Minima Basis approaches and compared to the recent precision measurements. The TB electronic structure calculations included over 3 million atoms. In contrast to previous effective mass based results, the quadratic Stark coefficient obtained from both theories agrees closely with the experiments. This work represents the most sensitive and precise comparison between theory and experiment for single donor spin control. It is also shown that there is a significant linear Stark effect for an impurity near the interface, whereas, far from the interface, the quadratic Stark effect dominates. Such precise control of single donor spin states is required particularly in quantum computing applications of single donor electronics, which forms the driving motivation of this work.

  7. Control of single-spin magnetic anisotropy by exchange coupling.

    PubMed

    Oberg, Jenny C; Calvo, M Reyes; Delgado, Fernando; Moro-Lagares, María; Serrate, David; Jacob, David; Fernández-Rossier, Joaquín; Hirjibehedin, Cyrus F

    2014-01-01

    The properties of quantum systems interacting with their environment, commonly called open quantum systems, can be affected strongly by this interaction. Although this can lead to unwanted consequences, such as causing decoherence in qubits used for quantum computation, it can also be exploited as a probe of the environment. For example, magnetic resonance imaging is based on the dependence of the spin relaxation times of protons in water molecules in a host's tissue. Here we show that the excitation energy of a single spin, which is determined by magnetocrystalline anisotropy and controls its stability and suitability for use in magnetic data-storage devices, can be modified by varying the exchange coupling of the spin to a nearby conductive electrode. Using scanning tunnelling microscopy and spectroscopy, we observe variations up to a factor of two of the spin excitation energies of individual atoms as the strength of the spin's coupling to the surrounding electronic bath changes. These observations, combined with calculations, show that exchange coupling can strongly modify the magnetic anisotropy. This system is thus one of the few open quantum systems in which the energy levels, and not just the excited-state lifetimes, can be renormalized controllably. Furthermore, we demonstrate that the magnetocrystalline anisotropy, a property normally determined by the local structure around a spin, can be tuned electronically. These effects may play a significant role in the development of spintronic devices in which an individual magnetic atom or molecule is coupled to conducting leads. PMID:24317285

  8. Manipulating decoherence of a single solid-state spin by quantum control of its spin bath environment

    NASA Astrophysics Data System (ADS)

    de Lange, Gijs; van der Sar, Toeno; Blok, Machiel; Wang, Zhihui; Dobrovitski, Viatcheslav; Hanson, Ronald

    2011-03-01

    The coherence of solid-state spins is limited by uncontrolled interactions with their spin environment. High-fidelity single-spin control can be used to prolong the coherence by dynamically decoupling the spin from the environment [see De Lange et al., Science 330, 60 (2010)]. Here, we demonstrate a new approach towards decoherence control based on coherent manipulation of the spin bath environment itself. Our system consists of a single NV center spin in diamond, surrounded by a bath of electronic spins belonging to nitrogen impurities. By driving the bath spins resonantly and using the NV spin as a sensor, we are able to detect all transitions of the bath spins and demonstrate independent quantum control of each of them. This newly gained control opens the door to a number of exciting experiments such as measurement of the spin bath dynamics, manipulation of the spin bath correlation time, decoherence editing, and protection of NV spin coherence by suppressing the dynamics in its spin environment. In this talk we will present our latest results towards these goals.

  9. All optical control of a single electron spin in diamond

    E-print Network

    Yiwen Chu; Matthew Markham; Daniel J. Twitchen; Mikhail D. Lukin

    2014-09-22

    Precise coherent control of the individual electronic spins associated with atom-like impurities in the solid state is essential for applications in quantum information processing and quantum metrology. We demonstrate all-optical initialization, fast coherent manipulation, and readout of the electronic spin of the negatively charged nitrogen-vacancy (NV$^-$) center in diamond at T$\\sim$7K. We then present the observation of a novel double-dark resonance in the spectroscopy of an individual NV center. These techniques open the door for new applications ranging from robust manipulation of spin states using geometric quantum gates to quantum sensing and information processing.

  10. Fast Electrical Control of Single Electron Spins in Quantum Dots with Vanishing Influence from Nuclear Spins

    NASA Astrophysics Data System (ADS)

    Yoneda, J.; Otsuka, T.; Nakajima, T.; Takakura, T.; Obata, T.; Pioro-Ladrière, M.; Lu, H.; Palmstrøm, C. J.; Gossard, A. C.; Tarucha, S.

    2014-12-01

    We demonstrate fast universal electrical spin manipulation with inhomogeneous magnetic fields. With fast Rabi frequency up to 127 MHz, we leave the conventional regime of strong nuclear-spin influence and observe a spin-flip fidelity >96 % , a distinct chevron Rabi pattern in the spectral-time domain, and a spin resonance linewidth limited by the Rabi frequency, not by the dephasing rate. In addition, we establish fast z rotations up to 54 MHz by directly controlling the spin phase. Our findings will significantly facilitate tomography and error correction with electron spins in quantum dots.

  11. Coherent control of single spins in silicon carbide at room temperature

    NASA Astrophysics Data System (ADS)

    Widmann, Matthias; Lee, Sang-Yun; Rendler, Torsten; Son, Nguyen Tien; Fedder, Helmut; Paik, Seoyoung; Yang, Li-Ping; Zhao, Nan; Yang, Sen; Booker, Ian; Denisenko, Andrej; Jamali, Mohammad; Momenzadeh, S. Ali; Gerhardt, Ilja; Ohshima, Takeshi; Gali, Adam; Janzén, Erik; Wrachtrup, Jörg

    2015-02-01

    Spins in solids are cornerstone elements of quantum spintronics. Leading contenders such as defects in diamond or individual phosphorus dopants in silicon have shown spectacular progress, but either lack established nanotechnology or an efficient spin/photon interface. Silicon carbide (SiC) combines the strength of both systems: it has a large bandgap with deep defects and benefits from mature fabrication techniques. Here, we report the characterization of photoluminescence and optical spin polarization from single silicon vacancies in SiC, and demonstrate that single spins can be addressed at room temperature. We show coherent control of a single defect spin and find long spin coherence times under ambient conditions. Our study provides evidence that SiC is a promising system for atomic-scale spintronics and quantum technology.

  12. Symmetry & Controllability for Spin Networks with a Single-Node Control

    E-print Network

    Xiaoting Wang; Peter Pemberton-Ross; Sophie G Schirmer

    2011-02-17

    We consider the relation of symmetries and subspace controllability for spin networks with XXZ coupling subject to control of a single node by a local potential (Z-control). Such networks decompose into excitation subspaces. Focusing on the single excitation subspace it is shown that for single-node Z-controls external symmetries are characterized by eigenstates of the system Hamiltonian that have zero overlap with the control node, and there are no internal symmetries. It is further shown that there are symmetries that persist even in the presence of random perturbations. For uniformly coupled XXZ chains a characterization of all possible symmetries is given, which shows a strong dependence on the position of the node we control. Finally, it is shown rigorously for uniform Heisenberg and XX chains subject to single-node Z-control that the lack of symmetry is not only necessary but sufficient for subspace controllability. The latter approach is then generalized to establish controllability results for simple branched networks.

  13. Control of the cavity reflectivity using a single quantum dot spin

    NASA Astrophysics Data System (ADS)

    Sun, Shuo; Kim, Hyochul; Solomon, Glenn; Waks, Edo

    2015-03-01

    The implementation of quantum network and distributive quantum information processing relies on interaction between stationary matter qubits and flying photons. The spin of a single electron or hole confined in a quantum dot is considered as promising matter qubit as it possesses microsecond coherence time and allows picosecond timescale control using optical pulses. The quantum dot spin can also interact with a photon by controlling the optical response of a strongly coupled cavity. Yet all the experimental demonstrations of the cavity spectrum control have used neutral dots. The spin-dependent cavity spectrum for a strongly coupled charged quantum dot and cavity system has not been reported. Here, we report an experimental realization of a spin-photon interface using a strongly coupled quantum dot and cavity system. We show large modulation of the cavity reflection spectrum by manipulating the spin states of the quantum dot. The spin-photon interface is crucial for realizing a quantum logic gate or generating hybrid entanglement between a quantum dot spin and a photon. Our results represent an important step towards semiconductor based quantum logic devices and on-chip quantum networks.

  14. Reversible Single Spin Control of Individual Magnetic Molecule by Hydrogen Atom Adsorption

    PubMed Central

    Liu, Liwei; Yang, Kai; Jiang, Yuhang; Song, Boqun; Xiao, Wende; Li, Linfei; Zhou, Haitao; Wang, Yeliang; Du, Shixuan; Ouyang, Min; Hofer, Werner A.; Castro Neto, Antonio H.; Gao, Hong-Jun

    2013-01-01

    The reversible control of a single spin of an atom or a molecule is of great interest in Kondo physics and a potential application in spin based electronics. Here we demonstrate that the Kondo resonance of manganese phthalocyanine molecules on a Au(111) substrate have been reversibly switched off and on via a robust route through attachment and detachment of single hydrogen atom to the magnetic core of the molecule. As further revealed by density functional theory calculations, even though the total number of electrons of the Mn ion remains almost the same in the process, gaining one single hydrogen atom leads to redistribution of charges within 3d orbitals with a reduction of the molecular spin state from S = 3/2 to S = 1 that directly contributes to the Kondo resonance disappearance. This process is reversed by a local voltage pulse or thermal annealing to desorb the hydrogen atom. PMID:23383378

  15. Doping controlled spin reorientation in dysprosium-samarium orthoferrite single crystals

    NASA Astrophysics Data System (ADS)

    Cao, Shixun; Zhao, Weiyao; Kang, Baojuan; Zhang, Jincang; Ren, Wei

    2015-03-01

    As one of the most important phase transitions, spin reorientation (SR) in rare earth transition metal oxides draws much attention of emerging materials technologies. The origin of SR is the competition between different spin configurations which possess different free energy. We report the control of spin reorientation (SR) transition in perovskite rare earth orthoferrite Dy1-xSmxFeO3, a whole family of single crystals grown by optical floating zone method from x =0 to 1. Temperature dependence of the magnetizations under zero-field-cooling (ZFC) and field-cooling (FC) processes are studied. We have found a remarkable linear change of SR transition temperature in Sm-rich samples for x>0.2, which covers an extremely wide temperature range including room temperature. The a-axis magnetization curves under FCC process bifurcate from and then jump down to that of warming process (ZFC and FCW curves) in single crystals when x =0.5-0.9, suggesting complicated 4f-3d electron interactions among Dy3+-Sm3+, Dy3+-Fe3+, and Sm3+-Fe3+ sublattices of diverse magnetic configurations for materials physics and design. The magnetic properties and the doping effect on SR transition temperature in these single crystals might be useful in the spintronics device application. This work is supported by the National Key Basic Research Program of China (Grant No. 2015CB921600), and the National Natural Science Foundation of China (NSFC, Nos. 51372149, 50932003, 11274222).

  16. Analysis of state-of-the-art single-thruster attitude control techniques for spinning penetrator

    NASA Astrophysics Data System (ADS)

    Raus, Robin; Gao, Yang; Wu, Yunhua; Watt, Mark

    2012-07-01

    The attitude dynamics and manoeuvre survey in this paper is performed for a mission scenario involving a penetrator-type spacecraft: an axisymmetric prolate spacecraft spinning around its minor axis of inertia performing a 90° spin axis reorientation manoeuvre. In contrast to most existing spacecraft only one attitude control thruster is available, providing a control torque perpendicular to the spin axis. Having only one attitude thruster on a spinning spacecraft could be preferred for spacecraft simplicity (lower mass, lower power consumption etc.), or it could be imposed in the context of redundancy/contingency operations. This constraint does yield restrictions on the thruster timings, depending on the ratio of minor to major moments of inertia among other parameters. The Japanese Lunar-A penetrator spacecraft proposal is a good example of such a single-thruster spin-stabilised prolate spacecraft. The attitude dynamics of a spinning rigid body are first investigated analytically, then expanded for the specific case of a prolate and axisymmetric rigid body and finally a cursory exploration of non-rigid body dynamics is made. Next two well-known techniques for manoeuvring a spin-stabilised spacecraft, the Half-cone/Multiple Half-cone and the Rhumb line slew, are compared with two new techniques, the Sector-Arc Slew developed by Astrium Satellites and the Dual-cone developed at Surrey Space Centre. Each technique is introduced and characterised by means of simulation results and illustrations based on the penetrator mission scenario and a brief robustness analysis is performed against errors in moments of inertia and spin rate. Also, the relative benefits of each slew algorithm are discussed in terms of slew accuracy, energy (propellant) efficiency and time efficiency. For example, a sequence of half-cone manoeuvres (a Multi-half-cone manoeuvre) tends to be more energy-efficient than one half-cone for the same final slew angle, but more time-consuming. As another example, the new Sector-Arc Slew and Dual-cone techniques are designed to overcome a specific restriction on attainable slew angle that is associated with the half-cone manoeuvre, giving one additional degree of freedom for designers to fine-tune.

  17. Observation and electric current control of a local spin in a single-molecule magnet

    PubMed Central

    Komeda, Tadahiro; Isshiki, Hironari; Liu, Jie; Zhang, Yan-Feng; Lorente, Nicolás; Katoh, Keiichi; Breedlove, Brian K.; Yamashita, Masahiro

    2011-01-01

    In molecular spintronics, the spin state of a molecule may be switched on and off by changing the molecular structure. Here, we switch on and off the molecular spin of a double-decker bis(phthalocyaninato)terbium(III) complex (TbPc2) adsorbed on an Au(111) surface by applying an electric current via a scanning tunnelling microscope. The dI/dV curve of the tunnelling current recorded onto a TbPc2 molecule shows a Kondo peak, the origin of which is an unpaired spin of a ?-orbital of a phthalocyaninato (Pc) ligand. By applying controlled current pulses, we could rotate the upper Pc ligand in TbPc2, leading to the disappearance and reappearance of the Kondo resonance. The rotation shifts the molecular frontier-orbital energies, quenching the ?-electron spin. Reversible switching between two stable ligand orientations by applying a current pulse should make it possible to code information at the single-molecule level. PMID:21364556

  18. Electrical control of single hole spins in InSb nanowire quantum dots

    NASA Astrophysics Data System (ADS)

    Pribiag, Vlad; Nadj-Perge, Stevan; van den Berg, Johan; Frolov, Sergey; Plissard, Sebastien; Bakkers, Erik; Kouwenhoven, Leo

    2012-02-01

    The spin-orbit interaction provides an efficient handle for all-electric control of individual spins in quantum dots. Recently, III-V semiconductor nanowires, which have a strong spin-orbit coupling, have emerged as a promising platform for spin-based qubits. Previous work has been focused on the electrical control of electron spins in InAs nanowires. In contrast, spin-dependent quantum transport with holes has so far remained largely unexplored. Here, we demonstrate gate tuning from the few-electron double dot to the few-hole double-dot regimes in InSb nanowires and observe Pauli spin-blockade for both electrons and holes. We use electric-dipole spin resonance (EDSR) to determine the effective g-factors of the two types of carriers. EDSR control over the hole spins is promising for driving coherent rotations of hole-spin qubits. These hole qubits are expected to be less sensitive to hyperfine-mediated decoherence effects than electron-spin qubits as a result of the p-wave symmetry of the hole wavefunction.

  19. TRANSVERSITY SINGLE SPIN ASYMMETRIES.

    SciTech Connect

    BOER,D.

    2001-04-27

    The theoretical aspects of two leading twist transversity single spin asymmetries, one arising from the Collins effect and one from the interference fragmentation functions, are reviewed. Issues of factorization, evolution and Sudakov factors for the relevant observables are discussed. These theoretical considerations pinpoint the most realistic scenarios towards measurements of transversity.

  20. Mechanisms for Electric Field Control of Single Spin Relaxation in Double Quantum Dots

    NASA Astrophysics Data System (ADS)

    Srinivasa, V.; Nowack, K. C.; Shafiei, M.; Vandersypen, L. M. K.; Taylor, J. M.

    2013-03-01

    We theoretically investigate electrically-tunable spin-flip transitions for a single electron confined within a double quantum dot. In the presence of spin-orbit and hyperfine interactions, the rate at which phonon-induced spin relaxation occurs depends non-monotonically on the detuning between the dots. We analyze this detuning dependence for both direct decay to the ground state and indirect decay via an intermediate excited state of the double dot. A description in terms of a simple toy model captures characteristic features of the relaxation rate recently measured for GaAs double quantum dots. Our results suggest that spin-orbit mediated relaxation via phonons serves as the dominant mechanism through which the electron spin-flip rate in these systems varies with detuning. We theoretically investigate electrically-tunable spin-flip transitions for a single electron confined within a double quantum dot. In the presence of spin-orbit and hyperfine interactions, the rate at which phonon-induced spin relaxation occurs depends non-monotonically on the detuning between the dots. We analyze this detuning dependence for both direct decay to the ground state and indirect decay via an intermediate excited state of the double dot. A description in terms of a simple toy model captures characteristic features of the relaxation rate recently measured for GaAs double quantum dots. Our results suggest that spin-orbit mediated relaxation via phonons serves as the dominant mechanism through which the electron spin-flip rate in these systems varies with detuning. Support from DARPA MTO and IARPA is gratefully acknowledged.

  1. High-frequency electrical charge and spin control in a single InGaAs quantum dot

    NASA Astrophysics Data System (ADS)

    Nannen, J.; Quitsch, W.; Eliasson, S.; Kümmell, T.; Bacher, G.

    2012-01-01

    We report on the charging behavior of a single self-assembled InGaAs quantum dot with unpolarized and spin-polarized electrons under direct current (DC) and high-frequency biasing. The tunnel coupling of the quantum dot to a spin-polarized electron reservoir leads to characteristic voltage dependence of the polarization of the neutral and the negatively charged exciton emissions in a magnetic field under DC biasing conditions. Via high-frequency adaptation of the device, electrical control of the charge state of the single quantum dot in the gigahertz regime is achieved. A technique for optical preparation of single holes and subsequent electrical charging via high-frequency voltage pulses allows for an ultrafast injection and readout of spin-polarized electrons on a subnanosecond timescale.

  2. Gate control of single-electron spins: a multi-scale numerical simulation approach

    NASA Astrophysics Data System (ADS)

    Prabhakar, Sanjay; Raynolds, James

    2008-03-01

    Among recent proposals for next-generation, non-charge-based logic is the notion that a single electron can be trapped and its spin manipulated through the application of gate voltages (Rev. Mod. Phys. 79, 1217 (2007)). In this talk we present numerical simulations of such Spin Single Electron Transistors (SSET) in support of experimental work at the University at Albany, State University of New York aimed at the practical development of post-CMOS concepts and devices. We use a multi-scale simulation strategy to self-consistently solve the Schroedinger-Poisson equations (with and without exchange-correlation effects) to obtain realistic confining and gating potentials for realistic device geometries. We discuss scaling of the equations in the various sub domains of a finite-element discretization to span the dimensions from the micron scale of the gate structures down the single-electron level. We will discuss the calculation of the gate-tuned ``g-factor" for electrons and holes (Phys. Rev. B 68, 155330 (2003)) in electro-statically- and lithographically-defined quantum dots including the Rashba and Dresselhaus spin-orbit interactions computed numerically from realistic wave functions. This work is supported through funding from the DARPA/NRI INDEX center.

  3. Control of coherence among the spins of a single electron and the three nearest neighbor 13C nuclei of a nitrogen-vacancy center in diamond

    NASA Astrophysics Data System (ADS)

    Shimo-Oka, T.; Kato, H.; Yamasaki, S.; Jelezko, F.; Miwa, S.; Suzuki, Y.; Mizuochi, N.

    2015-04-01

    Individual nuclear spins in diamond can be optically detected through hyperfine couplings with the electron spin of a single nitrogen-vacancy (NV) center; such nuclear spins have outstandingly long coherence times. Among the hyperfine couplings in the NV center, the nearest neighbor 13C nuclear spins have the largest coupling strength. Nearest neighbor 13C nuclear spins have the potential to perform fastest gate operations, providing highest fidelity in quantum computing. Herein, we report on the control of coherences in the NV center where all three nearest neighbor carbons are of the 13C isotope. Coherence among the three and four qubits are generated and analyzed at room temperature.

  4. Single-atom spin qubits in silicon

    NASA Astrophysics Data System (ADS)

    Dzurak, Andrew

    2013-03-01

    Spin qubits in silicon are excellent candidates for scalable quantum information processing (QIP) due to their long coherence times and the enormous investment in silicon MOS technology. Here I discuss qubits based upon single phosphorus (P) dopant atoms in Si. Projective readout of such qubits had proved challenging until single-shot measurement of a single donor electron spin was demonstrated using a silicon single electron transistor (Si-SET) and the process of spin-to-charge conversion. The measurement gave readout fidelities > 90% and spin lifetimes T1e > 6 s, opening the path to demonstration of electron and nuclear spin qubits in silicon. Integrating an on-chip microwave transmission line enabled single-electron spin resonance (ESR) of the P donor electron. We used this to demonstrate Rabi oscillations of the electron spin qubit, while a Hahn echo sequence revealed electron spin coherence times T2e > 0.2 ms. This time is expected to become much longer in isotopically enriched 28Si devices. We also achieved single-shot readout of the 31P nuclear spin (with fidelity > 99.6%) by monitoring the two hyperfine-split ESR lines of the P donor system. By applying (local) NMR pulses we demonstrated coherent control of the nuclear spin qubit, giving a coherence time T2n > 60 ms. Spin qubits in silicon are excellent candidates for scalable quantum information processing (QIP) due to their long coherence times and the enormous investment in silicon MOS technology. Here I discuss qubits based upon single phosphorus (P) dopant atoms in Si. Projective readout of such qubits had proved challenging until single-shot measurement of a single donor electron spin was demonstrated using a silicon single electron transistor (Si-SET) and the process of spin-to-charge conversion. The measurement gave readout fidelities > 90% and spin lifetimes T1e > 6 s, opening the path to demonstration of electron and nuclear spin qubits in silicon. Integrating an on-chip microwave transmission line enabled single-electron spin resonance (ESR) of the P donor electron. We used this to demonstrate Rabi oscillations of the electron spin qubit, while a Hahn echo sequence revealed electron spin coherence times T2e > 0.2 ms. This time is expected to become much longer in isotopically enriched 28Si devices. We also achieved single-shot readout of the 31P nuclear spin (with fidelity > 99.6%) by monitoring the two hyperfine-split ESR lines of the P donor system. By applying (local) NMR pulses we demonstrated coherent control of the nuclear spin qubit, giving a coherence time T2n > 60 ms. Device fabrication was undertaken at the Australian National Fabrication Facility. This work was supported by the Australian Research Council Centre for Quantum Computation and Communication Technology and the U.S. Army Research Office (W911NF-08-1-0527).

  5. Gate controlled spin pumping at a quantum spin Hall edge

    NASA Astrophysics Data System (ADS)

    Narayan, Awadhesh; Hurley, Aaron; Sanvito, Stefano

    2013-09-01

    We propose a four-terminal device designed to manipulate by all electrical means the spin of a magnetic adatom positioned at the edge of a quantum spin Hall insulator. We show that an electrical gate, able to tune the interface resistance between a quantum spin Hall insulator and the source and drain electrodes, can switch the device between two regimes: one where the system exhibits spin pumping and the other where the adatom remains in its ground state. This demonstrates an all-electrical route to control single spins by exploiting helical edge states of topological materials.

  6. Control of electron spin decoherence in nuclear spin baths

    NASA Astrophysics Data System (ADS)

    Liu, Ren-Bao

    2011-03-01

    Nuclear spin baths are a main mechanism of decoherence of spin qubits in solid-state systems, such as quantum dots and nitrogen-vacancy (NV) centers of diamond. The decoherence results from entanglement between the electron and nuclear spins, established by quantum evolution of the bath conditioned on the electron spin state. When the electron spin is flipped, the conditional bath evolution is manipulated. Such manipulation of bath through control of the electron spin not only leads to preservation of the center spin coherence but also demonstrates quantum nature of the bath. In an NV center system, the electron spin effectively interacts with hundreds of 13 C nuclear spins. Under repeated flip control (dynamical decoupling), the electron spin coherence can be preserved for a long time (> 1 ms) . Thereforesomecharacteristicoscillations , duetocouplingtoabonded 13 C nuclear spin pair (a dimer), are imprinted on the electron spin coherence profile, which are very sensitive to the position and orientation of the dimer. With such finger-print oscillations, a dimer can be uniquely identified. Thus, we propose magnetometry with single-nucleus sensitivity and atomic resolution, using NV center spin coherence to identify single molecules. Through the center spin coherence, we could also explore the many-body physics in an interacting spin bath. The information of elementary excitations and many-body correlations can be extracted from the center spin coherence under many-pulse dynamical decoupling control. Another application of the preserved spin coherence is identifying quantumness of a spin bath through the back-action of the electron spin to the bath. We show that the multiple transition of an NV center in a nuclear spin bath can have longer coherence time than the single transition does, when the classical noises due to inhomogeneous broadening is removed by spin echo. This counter-intuitive result unambiguously demonstrates the quantumness of the nuclear spin bath. This work was supported by Hong Kong RGC/GRF CUHK402207, CUHK402209, and CUHK402410. The author acknowledges collaboration with Nan Zhao, Jian-Liang Hu, Sai Wah Ho, Jones T. K. Wan, and Jiangfeng Du.

  7. Coherent control of spin squeezing

    E-print Network

    C. K. Law; H. T. Ng; P. T. Leung

    2000-07-18

    We report an interaction that controls spin squeezing in a collection of spin 1/2 particles. We describe how spin squeezing can be generated and maintained in time. Our scheme can be applied to control the spin squeezing in a Bose condensate with two internal spin states.

  8. Quark Correlations and Single-Spin Asymmetries

    E-print Network

    Quark Correlations and Single-Spin Asymmetries Matthias Burkardt burkardt@nmsu.edu New Mexico State University Las Cruces, NM, 88003, U.S.A. Quark Correlations and Single-Spin Asymmetries ­ p.1 Implications for nucleon structure Summary Quark Correlations and Single-Spin Asymmetries ­ p.2/38 #12;What

  9. Detection and Control of Individual Nuclear Spins Using a Weakly Coupled Electron Spin

    SciTech Connect

    Taminiau, T.H.; Wagenaar, J.J.T.; van der Sar, T.; Jelezko, F.; Dobrovitski, Viatcheslav V.; Hanson, R.

    2012-09-28

    We experimentally isolate, characterize, and coherently control up to six individual nuclear spins that are weakly coupled to an electron spin in diamond. Our method employs multipulse sequences on the electron spin that resonantly amplify the interaction with a selected nuclear spin and at the same time dynamically suppress decoherence caused by the rest of the spin bath. We are able to address nuclear spins with interaction strengths that are an order of magnitude smaller than the electron spin dephasing rate. Our results provide a route towards tomography with single-nuclear-spin sensitivity and greatly extend the number of available quantum bits for quantum information processing in diamond.

  10. Feedback control of spin systems

    E-print Network

    Claudio Altafini

    2006-01-03

    The feedback stabilization problem for ensembles of coupled spin 1/2 systems is discussed from a control theoretic perspective. The noninvasive nature of the bulk measurement allows for a fully unitary and deterministic closed loop. The Lyapunov-based feedback design presented does not require spins that are selectively addressable. With this method, it is possible to obtain control inputs also for difficult tasks, like suppressing undesired couplings in identical spin systems.

  11. Spin effects in single-electron transistors

    E-print Network

    Granger, Ghislain

    2005-01-01

    Basic electron transport phenomena observed in single-electron transistors (SETs) are introduced, such as Coulomb-blockade diamonds, inelastic cotunneling thresholds, the spin-1/2 Kondo effect, and Fano interference. With ...

  12. Dynamic nuclear polarization with single electron spins.

    PubMed

    Petta, J R; Taylor, J M; Johnson, A C; Yacoby, A; Lukin, M D; Marcus, C M; Hanson, M P; Gossard, A C

    2008-02-15

    We polarize nuclear spins in a GaAs double quantum dot by controlling two-electron spin states near the anticrossing of the singlet (S) and m(S)= +1 triplet (T+) using pulsed gates. An initialized S state is cyclically brought into resonance with the T+ state, where hyperfine fields drive rapid rotations between S and T+, "flipping" an electron spin and "flopping" a nuclear spin. The resulting Overhauser field approaches 80 mT, in agreement with a simple rate-equation model. A self-limiting pulse sequence is developed that allows the steady-state nuclear polarization to be set using a gate voltage. PMID:18352516

  13. Nonequilibrium intrinsic spin torque in a single nanomagnet

    NASA Astrophysics Data System (ADS)

    Manchon, Aurelien

    2009-03-01

    The spin transfer torque usually observed in metallic and tunneling spin-valves, as well as magnetic domain walls, comes from the transfer of the transverse spin-current of conduction electrons to the magnetization [1]. Therefore, it requires both a non collinear configuration of the magnetic structure (or inhomogeneous magnetic texture in the case of domain walls) and magneto-resistive effects. However, a number of magnetic systems show magneto-resistive effects in a single magnetic layer, such as anisotropic magnetoresistance (AMR) [2]. In the presence of spin-orbit interaction (SOI) the electron scattering depends on the magnetization direction. Recent theoretical studies suggest that in such systems, a transverse component of the spin density builds up, due to the spin-dependent scattering introduced by the spin-orbit coupling. Consequently, a transverse spin density arises from intrinsic properties of the band structure without the need of non-collinear magnetization texture. In the case of a single ferromagnet with spin-orbit interaction, the exchange interaction between the accumulated spin and the magnetization gives rise a spin torque on the magnetization. We show that this torque can be used to control the magnetization direction injecting current densities as low as 10?5-10?6 A/cm?2, comparable or lower than the spin transfer effect. We first study the general case of a single ferromagnetic layer with spin-orbit interaction and then focus on the cases of effective Hamiltonians, such as Rashba and Dresselhaus SOI, as well as Luttinger hole systems. We discuss the relation between the spin torque and the spatial inversion symmetry of various forms of spin-orbit couplings and compare this spin torque with the conventional spin transfer torque. We finally discuss several magnetic systems for possible experimental realization. This work was done in collaboration with Shufeng Zhang. [1] ] J.C. Slonczewski, J. Magn. Magn. Mater. 159, L1 (1996); L. Berger, Phys. Rev. B 54, 9353 (1996). [2] T.R. McGuire and R.I. Potter, IEEE Trans. Mag. 11, 1018 (1975).

  14. Single spin stochastic optical reconstruction microscopy

    E-print Network

    Pfender, Matthias; Waldherr, Gerald; Wrachtrup, Jörg

    2014-01-01

    We experimentally demonstrate precision addressing of single quantum emitters by combined optical microscopy and spin resonance techniques. To this end we utilize nitrogen-vacancy (NV) color centers in diamond confined within a few ten nanometers as individually resolvable quantum systems. By developing a stochastic optical reconstruction microscopy (STORM) technique for NV centers we are able to simultaneously perform sub diffraction-limit imaging and optically detected spin resonance (ODMR) measurements on NV spins. This allows the assignment of spin resonance spectra to individual NV center locations with nanometer scale resolution and thus further improves spatial discrimination. For example, we resolved formerly indistinguishable emitters by their spectra. Furthermore, ODMR spectra contain metrology information allowing for sub diffraction-limit sensing of, for instance, magnetic or electric fields with inherently parallel data acquisition. As an example, we have detected nuclear spins with nanometer sca...

  15. Gigahertz dynamics of a strongly driven single quantum spin.

    PubMed

    Fuchs, G D; Dobrovitski, V V; Toyli, D M; Heremans, F J; Awschalom, D D

    2009-12-11

    Two-level systems are at the core of numerous real-world technologies such as magnetic resonance imaging and atomic clocks. Coherent control of the state is achieved with an oscillating field that drives dynamics at a rate determined by its amplitude. As the strength of the field is increased, a different regime emerges where linear scaling of the manipulation rate breaks down and complex dynamics are expected. By calibrating the spin rotation with an adiabatic passage, we have measured the room-temperature "strong-driving" dynamics of a single nitrogen vacancy center in diamond. With an adiabatic passage to calibrate the spin rotation, we observed dynamics on sub-nanosecond time scales. Contrary to conventional thinking, this breakdown of the rotating wave approximation provides opportunities for time-optimal quantum control of a single spin. PMID:19965386

  16. Tunable Spin Loading and T1 of a Silicon Spin Qubit Measured by Single-Shot Readout

    NASA Astrophysics Data System (ADS)

    Simmons, C. B.; Prance, J. R.; van Bael, B. J.; Koh, Teck Seng; Shi, Zhan; Savage, D. E.; Lagally, M. G.; Joynt, R.; Friesen, Mark; Coppersmith, S. N.; Eriksson, M. A.

    2011-04-01

    We demonstrate single-shot readout of a silicon quantum dot spin qubit, and we measure the spin relaxation time T1. We show that the rate of spin loading can be tuned by an order of magnitude by changing the amplitude of a pulsed-gate voltage, and the fraction of spin-up electrons loaded can also be controlled. This tunability arises because electron spins can be loaded through an orbital excited state. Using a theory that includes excited states of the dot and energy-dependent tunneling, we find that a global fit to the loading rate and spin-up fraction is in good agreement with the data.

  17. Neutron single target spin asymmetries in SIDIS

    SciTech Connect

    Evaristo Cisbani

    2010-04-01

    The experiment E06-010 in Hall A at Jefferson Lab took data between November 2008 and February 2009 to directly measure, for the first time, the pion (and kaon) single "neutron" target-spin asymmetry (SSA) in semi-inclusive DIS from a polarized 3He target. Collins, Sivers (and Pretzelosity) neutron asymmetries are going to be extracted from the measured SSA. Details of the experiment are described together with the preliminary results of the ongoing analysis. Near future Hall A experiments on transverse nucleon spin structure are shorty reviewed.

  18. Single-spin stochastic optical reconstruction microscopy.

    PubMed

    Pfender, Matthias; Aslam, Nabeel; Waldherr, Gerald; Neumann, Philipp; Wrachtrup, Jörg

    2014-10-14

    We experimentally demonstrate precision addressing of single-quantum emitters by combined optical microscopy and spin resonance techniques. To this end, we use nitrogen vacancy (NV) color centers in diamond confined within a few ten nanometers as individually resolvable quantum systems. By developing a stochastic optical reconstruction microscopy (STORM) technique for NV centers, we are able to simultaneously perform sub-diffraction-limit imaging and optically detected spin resonance (ODMR) measurements on NV spins. This allows the assignment of spin resonance spectra to individual NV center locations with nanometer-scale resolution and thus further improves spatial discrimination. For example, we resolved formerly indistinguishable emitters by their spectra. Furthermore, ODMR spectra contain metrology information allowing for sub-diffraction-limit sensing of, for instance, magnetic or electric fields with inherently parallel data acquisition. As an example, we have detected nuclear spins with nanometer-scale precision. Finally, we give prospects of how this technique can evolve into a fully parallel quantum sensor for nanometer resolution imaging of delocalized quantum correlations. PMID:25267655

  19. Measuring mechanical motion with a single spin

    E-print Network

    S. D. Bennett; S. Kolkowitz; Q. P. Unterreithmeier; P. Rabl; A. C. Bleszynski Jayich; J. G. E. Harris; M. D. Lukin

    2012-05-30

    We study theoretically the measurement of a mechanical oscillator using a single two level system as a detector. In a recent experiment, we used a single electronic spin associated with a nitrogen vacancy center in diamond to probe the thermal motion of a magnetized cantilever at room temperature {Kolkowitz et al., Science 335, 1603 (2012)}. Here, we present a detailed analysis of the sensitivity limits of this technique, as well as the possibility to measure the zero point motion of the oscillator. Further, we discuss the issue of measurement backaction in sequential measurements and find that although backaction heating can occur, it does not prohibit the detection of zero point motion. Throughout the paper we focus on the experimental implementation of a nitrogen vacancy center coupled to a magnetic cantilever; however, our results are applicable to a wide class of spin-oscillator systems. Implications for preparation of nonclassical states of a mechanical oscillator are also discussed.

  20. Gate control of single-electron spins through Berry Phase in a realistic asymmetric confining potentials in III-V semiconductor Quantum Dots

    NASA Astrophysics Data System (ADS)

    Prabhakar, Sanjay; Raynolds, James

    2009-03-01

    Among recent proposals for next-generation, non-charge-based logic is the notion that a single electron can be trapped and its spin can be manipulated through the application of gate voltages (Rev. Mod. Phys.79, 1217 (2007)). In this talk we present numerical simulations of Berry Phase of electron spins in single electron devices for realistic asymmetric confining potentials in support of experimental work at the University at Albany, State University of New York aimed at the practical development of post-CMOS concepts and devices. We solve the Schr"odinger equation including spin-orbit effects using a numerical finite-element based technique. We will discuss the calculation of Berry Phase for electrons (Phys. Rev. B 73, 125330 (2006)) in electrostatically defined quantum dots including the Rashba and Dresselhaus spin-orbit interactions computed numerically from realistic asymmetric confining potentials. The new simulation results open the possibility of spin manipulation through the gate induced Berry phase. This work is supported through funding from the DARPA/NRI INDEX center.

  1. Single Spin Asymmetries in the BRAHMS Experiment

    E-print Network

    F. Videbaek; for the BRAHMS collaboration

    2006-01-04

    The BRAHMS experiment at RHIC has measured the transverse single spin asymmetries in polarized pp induced pion production at RHIC. The results from the RHIC run-5 shows a significant asymmetry for pi+ and pi- at moderate xF. The trend of the data is in agreement with lower energy results while the absolute values are surprisingly large. The pT dependence is approximately inversely propotional to pT in agreement with the pQCD expectations.

  2. Robust control of individual nuclear spins in diamond

    E-print Network

    Benjamin Smeltzer; Jean McIntyre; Lilian Childress

    2009-09-22

    Isolated nuclear spins offer a promising building block for quantum information processing systems, but their weak interactions often impede preparation, control, and detection. Hyperfine coupling to a proximal electronic spin can enhance each of these processes. Using the electronic spin of the nitrogen-vacancy center as an intermediary, we demonstrate robust initialization, single-qubit manipulation, and direct optical readout of 13C, 15N, and 14N nuclear spins in diamond. These results pave the way for nitrogen nuclear spin based quantum information architectures in diamond.

  3. Spin-optical metamaterial route to spin-controlled photonics.

    PubMed

    Shitrit, Nir; Yulevich, Igor; Maguid, Elhanan; Ozeri, Dror; Veksler, Dekel; Kleiner, Vladimir; Hasman, Erez

    2013-05-10

    Spin optics provides a route to control light, whereby the photon helicity (spin angular momentum) degeneracy is removed due to a geometric gradient onto a metasurface. The alliance of spin optics and metamaterials offers the dispersion engineering of a structured matter in a polarization helicity-dependent manner. We show that polarization-controlled optical modes of metamaterials arise where the spatial inversion symmetry is violated. The emerged spin-split dispersion of spontaneous emission originates from the spin-orbit interaction of light, generating a selection rule based on symmetry restrictions in a spin-optical metamaterial. The inversion asymmetric metasurface is obtained via anisotropic optical antenna patterns. This type of metamaterial provides a route for spin-controlled nanophotonic applications based on the design of the metasurface symmetry properties. PMID:23661756

  4. Ultrafast optical control of individual quantum dot spin qubits

    NASA Astrophysics Data System (ADS)

    De Greve, Kristiaan; Press, David; McMahon, Peter L.; Yamamoto, Yoshihisa

    2013-09-01

    Single spins in semiconductor quantum dots form a promising platform for solid-state quantum information processing. The spin-up and spin-down states of a single electron or hole, trapped inside a quantum dot, can represent a single qubit with a reasonably long decoherence time. The spin qubit can be optically coupled to excited (charged exciton) states that are also trapped in the quantum dot, which provides a mechanism to quickly initialize, manipulate and measure the spin state with optical pulses, and to interface between a stationary matter qubit and a ‘flying’ photonic qubit for quantum communication and distributed quantum information processing. The interaction of the spin qubit with light may be enhanced by placing the quantum dot inside a monolithic microcavity. An entire system, consisting of a two-dimensional array of quantum dots and a planar microcavity, may plausibly be constructed by modern semiconductor nano-fabrication technology and could offer a path toward chip-sized scalable quantum repeaters and quantum computers. This article reviews the recent experimental developments in optical control of single quantum dot spins for quantum information processing. We highlight demonstrations of a complete set of all-optical single-qubit operations on a single quantum dot spin: initialization, an arbitrary SU(2) gate, and measurement. We review the decoherence and dephasing mechanisms due to hyperfine interaction with the nuclear-spin bath, and show how the single-qubit operations can be combined to perform spin echo sequences that extend the qubit decoherence from a few nanoseconds to several microseconds, more than 5 orders of magnitude longer than the single-qubit gate time. Two-qubit coupling is discussed, both within a single chip by means of exchange coupling of nearby spins and optically induced geometric phases, as well as over longer-distances. Long-distance spin-spin entanglement can be generated if each spin can emit a photon that is entangled with the spin, and these photons are then interfered. We review recent work demonstrating entanglement between a stationary spin qubit and a flying photonic qubit. These experiments utilize the polarization- and frequency-dependent spontaneous emission from the lowest charged exciton state to single spin Zeeman sublevels.

  5. Hyperfine switching triggered by resonant tunneling for the detection of a single nuclear spin qubit

    Microsoft Academic Search

    Tomofumi Tada

    2008-01-01

    A novel detection mechanism and a robust control of a single nuclear spin-flip by hyperfine interactions between the nuclear spin and tunneling electron spin are proposed on the basis of ab initio non-equilibrium Green's function calculations. The calculated relaxation times of the nuclear spin of proton in a nano-contact system, Pd(electrode)–H2–Pd(electrode), show that ON\\/OFF switching of hyperfine interactions is effectively

  6. Spin controlled optical radiation pressure.

    PubMed

    Tkachenko, Georgiy; Brasselet, Etienne

    2013-07-19

    We report on the full control of the optical radiation pressure at fixed photon flux and incident angle by the photon spin. This is done by using transparent chiral liquid crystal droplets that enable a strong coupling between the linear and angular degrees of freedom of a light field. From these results, we anticipate optical sorting of particles with different chirality as well as novel optical trapping and micromanipulation strategies. PMID:23909320

  7. Voltage tunability of single-spin states in a quantum dot.

    PubMed

    Bennett, Anthony J; Pooley, Matthew A; Cao, Yameng; Sköld, Niklas; Farrer, Ian; Ritchie, David A; Shields, Andrew J

    2013-01-01

    Single spins in the solid state offer a unique opportunity to store and manipulate quantum information, and to perform quantum-enhanced sensing of local fields and charges. Optical control of these systems using techniques developed in atomic physics has yet to exploit all the advantages of the solid state. Here we demonstrate voltage tunability of the spin energy-levels in a single quantum dot by modifying how spins sense magnetic field. We find that the in-plane g-factor varies discontinuously for electrons, as more holes are loaded onto the dot. In contrast, the in-plane hole g-factor varies continuously. The device can change the sign of the in-plane g-factor of a single hole, at which point an avoided crossing is observed in the two spin eigenstates. This is exactly what is required for universal control of a single spin with a single electrical gate. PMID:23443550

  8. Single spin optically detected magnetic resonance with 60-90 GHz (E-band) microwave resonators

    NASA Astrophysics Data System (ADS)

    Aslam, Nabeel; Pfender, Matthias; Stöhr, Rainer; Neumann, Philipp; Scheffler, Marc; Sumiya, Hitoshi; Abe, Hiroshi; Onoda, Shinobu; Ohshima, Takeshi; Isoya, Junichi; Wrachtrup, Jörg

    2015-06-01

    Magnetic resonance with ensembles of electron spins is commonly performed around 10 GHz, but also at frequencies above 240 GHz and in corresponding magnetic fields of over 9 T. However, experiments with single electron and nuclear spins so far only reach into frequency ranges of several 10 GHz, where existing coplanar waveguide structures for microwave (MW) delivery are compatible with single spin readout techniques (e.g., electrical or optical readout). Here, we explore the frequency range up to 90 GHz, with magnetic fields of up to ?3 T for single spin magnetic resonance in conjunction with optical spin readout. To this end, we develop MW resonators with optical single spin access. In our case, rectangular 60-90 GHz (E-band) waveguides guarantee low-loss supply of microwaves to the resonators. Three dimensional cavities, as well as coplanar waveguide resonators, enhance MW fields by spatial and spectral confinement with a MW efficiency of 1 . 36 mT / ?{ W } . We utilize single nitrogen vacancy (NV) centers as hosts for optically accessible spins and show that their properties regarding optical spin readout known from smaller fields (<0.65 T) are retained up to fields of 3 T. In addition, we demonstrate coherent control of single nuclear spins under these conditions. Furthermore, our results extend the applicable magnetic field range of a single spin magnetic field sensor. Regarding spin based quantum registers, high fields lead to a purer product basis of electron and nuclear spins, which promises improved spin lifetimes. For example, during continuous single-shot readout, the 14N nuclear spin shows second-long longitudinal relaxation times.

  9. Measuring mechanical motion with a single spin

    NASA Astrophysics Data System (ADS)

    Bennett, S. D.; Kolkowitz, S.; Unterreithmeier, Q. P.; Rabl, P.; Bleszynski Jayich, A. C.; Harris, J. G. E.; Lukin, M. D.

    2012-12-01

    We study theoretically the measurement of a mechanical oscillator using a single two-level system as a detector. In a recent experiment, we used a single electronic spin associated with a nitrogen-vacancy center in diamond to probe the thermal motion of a magnetized cantilever at room temperature (Kolkowitz et al 2012 Science 335 1603). Here, we present a detailed analysis of the sensitivity limits of this technique, as well as the possibility to measure the zero-point motion of the oscillator. Further, we discuss the issue of measurement backaction in sequential measurements and find that although backaction heating can occur, it does not prohibit the detection of zero-point motion. Throughout the paper, we focus on the experimental implementation of a nitrogen-vacancy center coupled to a magnetic cantilever; however, our results are applicable to a wide class of spin-oscillator systems. The implications for the preparation of nonclassical states of a mechanical oscillator are also discussed.

  10. Nanoscale Spin Seebeck Rectifier: Controlling Thermal Spin Transport across Insulating Magnetic Junctions with Localized Spin

    NASA Astrophysics Data System (ADS)

    Ren, Jie; Fransson, Jonas; Zhu, Jian-Xin

    2014-06-01

    The spin Seebeck effect is studied across a charge insulating magnetic junction, in which thermal-spin conjugate transport is assisted by the exchange interactions between the localized spin in the center and electrons in metallic leads. We show that, in contrast with bulk spin Seebeck effect, the figure of merit of such nanoscale thermal-spin conversion can be infinite, leading to the ideal Carnot efficiency in the linear response regime. We also find that in the nonlinear spin Seebeck transport regime the device possesses the asymmetric and negative differential spin Seebeck effects. In the last, the situations with leaking electron tunneling are also discussed. This nanoscale thermal spin rectifier, by tuning the junction parameters, can act as a spin Seebeck diode, spin Seebeck transistor, and spin Seebeck switch, which could have substantial implications for flexible thermal and information control in molecular spin caloritronics.

  11. Atomic-resolution single-spin magnetic resonance detection concept based on tunneling force microscopy

    NASA Astrophysics Data System (ADS)

    Payne, A.; Ambal, K.; Boehme, C.; Williams, C. C.

    2015-05-01

    A study of a force detected single-spin magnetic resonance measurement concept with atomic spatial resolution is presented. The method is based upon electrostatic force detection of spin-selection rule controlled single-electron tunneling between two electrically isolated paramagnetic states. Single-spin magnetic resonance detection is possible by measuring the force detected tunneling charge noise on and off spin resonance. Simulation results of this charge noise, based upon physical models of the tunneling and spin physics, are directly compared to measured atomic force microscopy system noise. The results show that the approach could provide single-spin measurement of electrically isolated qubit states with atomic spatial resolution at room temperature.

  12. Coherent control of opticallyinjected population spin in (111)-GaAs

    E-print Network

    Sipe,J. E.

    QTuJ3 Coherent control of opticallyinjected population spin in (111)-GaAs and Arthur L. Smirl Abstract: We demonstrate independent coherent control of population and spin in (111)- grown GaAs through and control of a spin-polarized carrier population through quantum interference of single photon absorption

  13. Controlling the quantum dynamics of a mesoscopic spin bath in diamond

    NASA Astrophysics Data System (ADS)

    de Lange, Gijs; van der Sar, Toeno; Blok, Machiel; Wang, Zhi-Hui; Dobrovitski, Viatcheslav; Hanson, Ronald

    2012-04-01

    Understanding and mitigating decoherence is a key challenge for quantum science and technology. The main source of decoherence for solid-state spin systems is the uncontrolled spin bath environment. Here, we demonstrate quantum control of a mesoscopic spin bath in diamond at room temperature that is composed of electron spins of substitutional nitrogen impurities. The resulting spin bath dynamics are probed using a single nitrogen-vacancy (NV) centre electron spin as a magnetic field sensor. We exploit the spin bath control to dynamically suppress dephasing of the NV spin by the spin bath. Furthermore, by combining spin bath control with dynamical decoupling, we directly measure the coherence and temporal correlations of different groups of bath spins. These results uncover a new arena for fundamental studies on decoherence and enable novel avenues for spin-based magnetometry and quantum information processing.

  14. Single transverse-spin asymmetry in QCD

    NASA Astrophysics Data System (ADS)

    Koike, Yuji

    2014-09-01

    So far large single transverse-spin asymmetries (SSA) have been observed in many high-energy processes such as semi-inclusive deep inelastic scattering and proton-proton collisions. Since the conventional parton model and perturbative QCD can not accomodate such large SSAs, the framework for QCD hard processes had to be extended to understand the mechanism of SSA. In this extended frameworks of QCD, intrinsic transverse momentum of partons and the multi-parton (quark-gluon and pure-gluonic) correlations in the hadrons, which were absent in the conventional framework, play a crucial role to cause SSAs, and well-defined formulation of these effects has been a big challenge for QCD theorists. Study on these effects has greatly promoted our understanding on QCD dynamics and hadron structure. In this talk, I will present an overview on these theoretical activity, emphasizing the important role of the Drell-Yan process.

  15. Dynamic control of spin wave spectra using spin-polarized currents

    SciTech Connect

    Wang, Qi; Zhang, Huaiwu, E-mail: hwzhang@uestc.edu.cn; Tang, Xiaoli; Bai, Feiming; Zhong, Zhiyong, E-mail: zzy@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Fangohr, Hans [Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2014-09-15

    We describe a method of controlling the spin wave spectra dynamically in a uniform nanostripe waveguide through spin-polarized currents. A stable periodic magnetization structure is observed when the current flows vertically through the center of nanostripe waveguide. After being excited, the spin wave is transmitted at the sides of the waveguide. Numerical simulations of spin-wave transmission and dispersion curves reveal a single, pronounced band gap. Moreover, the periodic magnetization structure can be turned on and off by the spin-polarized current. The switching process from full rejection to full transmission takes place within less than 3?ns. Thus, this type magnonic waveguide can be utilized for low-dissipation spin wave based filters.

  16. Technical Notes Single-Sensor Identification of Spinning

    E-print Network

    Huang, Xun

    Technical Notes Single-Sensor Identification of Spinning Mode Noise from Aircraft Engine Xun Huang of aircraft. The development of high bypass ratio turbofan aircraft engines makes spinning mode noise function of the first kind K = gain of Kalman filter k = spinning mode frequency, Hz ka = axial wave number

  17. Tunable spin loading and T1 of a silicon spin qubit measured by single-shot readout.

    PubMed

    Simmons, C B; Prance, J R; Van Bael, B J; Koh, Teck Seng; Shi, Zhan; Savage, D E; Lagally, M G; Joynt, R; Friesen, Mark; Coppersmith, S N; Eriksson, M A

    2011-04-15

    We demonstrate single-shot readout of a silicon quantum dot spin qubit, and we measure the spin relaxation time T1. We show that the rate of spin loading can be tuned by an order of magnitude by changing the amplitude of a pulsed-gate voltage, and the fraction of spin-up electrons loaded can also be controlled. This tunability arises because electron spins can be loaded through an orbital excited state. Using a theory that includes excited states of the dot and energy-dependent tunneling, we find that a global fit to the loading rate and spin-up fraction is in good agreement with the data. PMID:21568595

  18. Single-Spin Asymmetries in Inclusive and Exclusive Hadronic Processes

    E-print Network

    Dae Sung Hwang; Jong Hyun Kim; Seyong Kim

    2007-05-16

    We investigate the single-spin asymmetries in inclusive and exclusive processes of electron-proton scattering and electron-positron annihilation. In the decomposition of hadronic tensor, a Lorentz symmetric spin-dependent term is generally present. The existence of such a term implies single-spin asymmetries in these processes and these single-spin asymmetries for baryons can be understood in a unified manner. We argue that it is important to measure the single-spin asymmetries in both inclusive and exclusive processes for the $\\Lambda$ production at the present B-factories. This will lead to the first measurement of the structure function of the symmetric spin-dependent hadronic tensor in these processes.

  19. Optically driven Rabi oscillations and adiabatic passage of single electron spins in diamond.

    PubMed

    Golter, D Andrew; Wang, Hailin

    2014-03-21

    Rabi oscillations and adiabatic passage of single electron spins in a diamond nitrogen vacancy center are demonstrated with two Raman-resonant optical pulses that are detuned from the respective dipole optical transitions. We show that the optical spin control is nuclear-spin selective and can be robust against rapid decoherence, including radiative decay and spectral diffusion, of the underlying optical transitions. A direct comparison between the Rabi oscillation and the adiabatic passage, along with a detailed theoretical analysis, provides significant physical insights into the connections and differences between these coherent spin processes and also elucidates the role of spectral diffusion in these processes. The optically driven coherent spin processes enable the use of nitrogen vacancy excited states to mediate coherent spin-phonon coupling, opening the door to combining optical control of both spin and mechanical degrees of freedom. PMID:24702393

  20. Macroscopic rotation of photon polarization induced by a single spin

    NASA Astrophysics Data System (ADS)

    Arnold, Christophe; Demory, Justin; Loo, Vivien; Lemaître, Aristide; Sagnes, Isabelle; Glazov, Mikhaïl; Krebs, Olivier; Voisin, Paul; Senellart, Pascale; Lanco, Loïc

    2015-02-01

    Entangling a single spin to the polarization of a single incoming photon, generated by an external source, would open new paradigms in quantum optics such as delayed-photon entanglement, deterministic logic gates or fault-tolerant quantum computing. These perspectives rely on the possibility that a single spin induces a macroscopic rotation of a photon polarization. Such polarization rotations induced by single spins were recently observed, yet limited to a few 10?3 degrees due to poor spin–photon coupling. Here we report the enhancement by three orders of magnitude of the spin–photon interaction, using a cavity quantum electrodynamics device. A single hole spin in a semiconductor quantum dot is deterministically coupled to a micropillar cavity. The cavity-enhanced coupling between the incoming photons and the solid-state spin results in a polarization rotation by ±6° when the spin is optically initialized in the up or down state. These results open the way towards a spin-based quantum network.

  1. Macroscopic rotation of photon polarization induced by a single spin

    PubMed Central

    Arnold, Christophe; Demory, Justin; Loo, Vivien; Lemaître, Aristide; Sagnes, Isabelle; Glazov, Mikhaïl; Krebs, Olivier; Voisin, Paul; Senellart, Pascale; Lanco, Loïc

    2015-01-01

    Entangling a single spin to the polarization of a single incoming photon, generated by an external source, would open new paradigms in quantum optics such as delayed-photon entanglement, deterministic logic gates or fault-tolerant quantum computing. These perspectives rely on the possibility that a single spin induces a macroscopic rotation of a photon polarization. Such polarization rotations induced by single spins were recently observed, yet limited to a few 10?3 degrees due to poor spin–photon coupling. Here we report the enhancement by three orders of magnitude of the spin–photon interaction, using a cavity quantum electrodynamics device. A single hole spin in a semiconductor quantum dot is deterministically coupled to a micropillar cavity. The cavity-enhanced coupling between the incoming photons and the solid-state spin results in a polarization rotation by ±6° when the spin is optically initialized in the up or down state. These results open the way towards a spin-based quantum network. PMID:25687134

  2. RHIC spin flipper AC dipole controller

    SciTech Connect

    Oddo, P.; Bai, M.; Dawson, C.; Gassner, D.; Harvey, M.; Hayes, T.; Mernick, K.; Minty, M.; Roser, T.; Severino, F.; Smith, K.

    2011-03-28

    The RHIC Spin Flipper's five high-Q AC dipoles which are driven by a swept frequency waveform require precise control of phase and amplitude during the sweep. This control is achieved using FPGA based feedback controllers. Multiple feedback loops are used to and dynamically tune the magnets. The current implementation and results will be presented. Work on a new spin flipper for RHIC (Relativistic Heavy Ion Collider) incorporating multiple dynamically tuned high-Q AC-dipoles has been developed for RHIC spin-physics experiments. A spin flipper is needed to cancel systematic errors by reversing the spin direction of the two colliding beams multiple times during a store. The spin flipper system consists of four DC-dipole magnets (spin rotators) and five AC-dipole magnets. Multiple AC-dipoles are needed to localize the driven coherent betatron oscillation inside the spin flipper. Operationally the AC-dipoles form two swept frequency bumps that minimize the effect of the AC-dipole dipoles outside of the spin flipper. Both AC bumps operate at the same frequency, but are phase shifted from each other. The AC-dipoles therefore require precise control over amplitude and phase making the implementation of the AC-dipole controller the central challenge.

  3. Engineering near-infrared single-photon emitters with optically active spins in ultrapure silicon carbide.

    PubMed

    Fuchs, F; Stender, B; Trupke, M; Simin, D; Pflaum, J; Dyakonov, V; Astakhov, G V

    2015-01-01

    Vacancy-related centres in silicon carbide are attracting growing attention because of their appealing optical and spin properties. These atomic-scale defects can be created using electron or neutron irradiation; however, their precise engineering has not been demonstrated yet. Here, silicon vacancies are generated in a nuclear reactor and their density is controlled over eight orders of magnitude within an accuracy down to a single vacancy level. An isolated silicon vacancy serves as a near-infrared photostable single-photon emitter, operating even at room temperature. The vacancy spins can be manipulated using an optically detected magnetic resonance technique, and we determine the transition rates and absorption cross-section, describing the intensity-dependent photophysics of these emitters. The on-demand engineering of optically active spins in technologically friendly materials is a crucial step toward implementation of both maser amplifiers, requiring high-density spin ensembles, and qubits based on single spins. PMID:26151881

  4. Radio Frequency Scanning Tunneling Spectroscopy for Single-Molecule Spin Resonance

    NASA Astrophysics Data System (ADS)

    Müllegger, Stefan; Tebi, Stefano; Das, Amal K.; Schöfberger, Wolfgang; Faschinger, Felix; Koch, Reinhold

    2014-09-01

    We probe nuclear and electron spins in a single molecule even beyond the electromagnetic dipole selection rules, at readily accessible magnetic fields (few mT) and temperatures (5 K) by resonant radio-frequency current from a scanning tunneling microscope. We achieve subnanometer spatial resolution combined with single-spin sensitivity, representing a 10 orders of magnitude improvement compared to existing magnetic resonance techniques. We demonstrate the successful resonant spectroscopy of the complete manifold of nuclear and electronic magnetic transitions of up to ?Iz=±3 and ?Jz=±12 of single quantum spins in a single molecule. Our method of resonant radio-frequency scanning tunneling spectroscopy offers, atom-by-atom, unprecedented analytical power and spin control with an impact on diverse fields of nanoscience and nanotechnology.

  5. Radio frequency scanning tunneling spectroscopy for single-molecule spin resonance.

    PubMed

    Müllegger, Stefan; Tebi, Stefano; Das, Amal K; Schöfberger, Wolfgang; Faschinger, Felix; Koch, Reinhold

    2014-09-26

    We probe nuclear and electron spins in a single molecule even beyond the electromagnetic dipole selection rules, at readily accessible magnetic fields (few mT) and temperatures (5 K) by resonant radio-frequency current from a scanning tunneling microscope. We achieve subnanometer spatial resolution combined with single-spin sensitivity, representing a 10 orders of magnitude improvement compared to existing magnetic resonance techniques. We demonstrate the successful resonant spectroscopy of the complete manifold of nuclear and electronic magnetic transitions of up to ?I(z)=±3 and ?J(z)=±12 of single quantum spins in a single molecule. Our method of resonant radio-frequency scanning tunneling spectroscopy offers, atom-by-atom, unprecedented analytical power and spin control with an impact on diverse fields of nanoscience and nanotechnology. PMID:25302884

  6. Electric field control of spin transport

    Microsoft Academic Search

    Sangeeta Sahoo; Takis Kontos; Jürg Furer; Christian Hoffmann; Matthias Gräber; Audrey Cottet; Christian Schönenberger

    2005-01-01

    Spintronics aims to develop electronic devices whose resistance is controlled by the spin of the charge carriers that flow through them. This approach is illustrated by the operation of the most basic spintronic device, the spin valve, which can be formed if two ferromagnetic electrodes are separated by a thin tunnelling barrier. In most cases, its resistance is greater when

  7. OSP Quantum Mechanics: Single Measurments of Spin States Worksheet

    NSDL National Science Digital Library

    Belloni, Mario

    This set of tutorial worksheets, based on the OSP Quantum Mechanics Simulations, help students explore the measurement of quantum spins. The tutorial starts with an introduction of the physics of spins, and then presents the results of a single measurement on pure, mixed, and superposition states.

  8. Detecting and Polarizing Nuclear Spins with Double Resonance on a Single Electron Spin

    NASA Astrophysics Data System (ADS)

    London, P.; Scheuer, J.; Cai, J.-M.; Schwarz, I.; Retzker, A.; Plenio, M. B.; Katagiri, M.; Teraji, T.; Koizumi, S.; Isoya, J.; Fischer, R.; McGuinness, L. P.; Naydenov, B.; Jelezko, F.

    2013-08-01

    We report the detection and polarization of nuclear spins in diamond at room temperature by using a single nitrogen-vacancy (NV) center. We use Hartmann-Hahn double resonance to coherently enhance the signal from a single nuclear spin while decoupling from the noisy spin bath, which otherwise limits the detection sensitivity. As a proof of principle, we (i) observe coherent oscillations between the NV center and a weakly coupled nuclear spin and (ii) demonstrate nuclear-bath cooling, which prolongs the coherence time of the NV sensor by more than a factor of 5. Our results provide a route to nanometer scale magnetic resonance imaging and novel quantum information processing protocols.

  9. Single Spin Asymmetries in Heavy Quark and Antiquark Productions

    E-print Network

    Feng Yuan; Jian Zhou

    2008-06-11

    The single transverse spin asymmetries in heavy quark and anti-quark production from the quark-antiquark annihilation channel contribution is studied by taking into account the initial and final state interactions effects. Because of the different color charges, the final state interaction effects lead to about a factor of 3 difference in the spin asymmetry for heavy quark over that for the anti-quark in the valence region of low energy pp collisions. The experimental study of this model-independent prediction shall provide a crucial test for the underlying mechanism for the single spin asymmetry phenomena.

  10. Detection of atomic spin labels in a lipid bilayer using a single-spin nanodiamond probe.

    PubMed

    Kaufmann, Stefan; Simpson, David A; Hall, Liam T; Perunicic, Viktor; Senn, Philipp; Steinert, Steffen; McGuinness, Liam P; Johnson, Brett C; Ohshima, Takeshi; Caruso, Frank; Wrachtrup, Jörg; Scholten, Robert E; Mulvaney, Paul; Hollenberg, Lloyd

    2013-07-01

    Magnetic field fluctuations arising from fundamental spins are ubiquitous in nanoscale biology, and are a rich source of information about the processes that generate them. However, the ability to detect the few spins involved without averaging over large ensembles has remained elusive. Here, we demonstrate the detection of gadolinium spin labels in an artificial cell membrane under ambient conditions using a single-spin nanodiamond sensor. Changes in the spin relaxation time of the sensor located in the lipid bilayer were optically detected and found to be sensitive to near-individual (4 ± 2) proximal gadolinium atomic labels. The detection of such small numbers of spins in a model biological setting, with projected detection times of 1 s [corresponding to a sensitivity of ?5 Gd spins per Hz(1/2)], opens a pathway for in situ nanoscale detection of dynamical processes in biology. PMID:23776230

  11. Detection of atomic spin labels in a lipid bilayer using a single-spin nanodiamond probe

    PubMed Central

    Kaufmann, Stefan; Simpson, David A.; Hall, Liam T.; Perunicic, Viktor; Senn, Philipp; Steinert, Steffen; McGuinness, Liam P.; Johnson, Brett C.; Ohshima, Takeshi; Caruso, Frank; Wrachtrup, Jörg; Scholten, Robert E.; Mulvaney, Paul; Hollenberg, Lloyd

    2013-01-01

    Magnetic field fluctuations arising from fundamental spins are ubiquitous in nanoscale biology, and are a rich source of information about the processes that generate them. However, the ability to detect the few spins involved without averaging over large ensembles has remained elusive. Here, we demonstrate the detection of gadolinium spin labels in an artificial cell membrane under ambient conditions using a single-spin nanodiamond sensor. Changes in the spin relaxation time of the sensor located in the lipid bilayer were optically detected and found to be sensitive to near-individual (4 ± 2) proximal gadolinium atomic labels. The detection of such small numbers of spins in a model biological setting, with projected detection times of 1 s [corresponding to a sensitivity of ?5 Gd spins per Hz1/2], opens a pathway for in situ nanoscale detection of dynamical processes in biology. PMID:23776230

  12. Landau-Zener-Stuckelberg interferometry of a single electron spin in a noisy environment

    E-print Network

    Huang, Pu; Fang, Fang; Kong, Xi; Xu, Xiangkun; Ju, Chenyong; Du, Jiangfeng

    2011-01-01

    We demonstrate quantum coherent control of a single electron spin in a NV center in diamond using the Landau-Zener-Stuckelberg interferometry at room temperature. Interference pattern is observed oscillating as a function of microwave frequency. The decays in the visibility of the interference are well explained by numerical simulation which includes the thermal fluctuations of the nuclear bath which shows that Landau-Zener-Stuckelberg interferometry can be used for probing electron spin decoherence processes.

  13. Landau-Zener-Stuckelberg interferometry of a single electron spin in a noisy environment

    E-print Network

    Pu Huang; Jingwei Zhou; Fang Fang; Xi Kong; Xiangkun Xu; Chenyong Ju; Jiangfeng Du

    2011-06-08

    We demonstrate quantum coherent control of a single electron spin in a NV center in diamond using the Landau-Zener-Stuckelberg interferometry at room temperature. Interference pattern is observed oscillating as a function of microwave frequency. The decays in the visibility of the interference are well explained by numerical simulation which includes the thermal fluctuations of the nuclear bath which shows that Landau-Zener-Stuckelberg interferometry can be used for probing electron spin decoherence processes.

  14. Nanoscale magnetometry using a single spin system in diamond

    E-print Network

    R. S. Said; D. W. Berry; J. Twamley

    2011-03-24

    We propose a protocol to estimate magnetic fields using a single nitrogen-vacancy (N-V) center in diamond, where the estimate precision scales inversely with time, ~1/T$, rather than the square-root of time. The method is based on converting the task of magnetometry into phase estimation, performing quantum phase estimation on a single N-V nuclear spin using either adaptive or nonadaptive feedback control, and the recently demonstrated capability to perform single-shot readout within the N-V [P. Neumann et. al., Science 329, 542 (2010)]. We present numerical simulations to show that our method provides an estimate whose precision scales close to ~1/T (T is the total estimation time), and moreover will give an unambiguous estimate of the static magnetic field experienced by the N-V. By combining this protocol with recent proposals for scanning magnetometry using an N-V, our protocol will provide a significant decrease in signal acquisition time while providing an unambiguous spatial map of the magnetic field.

  15. Single Spin Measurement using Single Electron Transistors to Probe Two Electron Systems

    E-print Network

    B. E. Kane; N. S. McAlpine; A. S. Dzurak; R. G. Clark; G. J. Milburn; He Bi Sun; Howard Wiseman

    1999-06-17

    We present a method for measuring single spins embedded in a solid by probing two electron systems with a single electron transistor (SET). Restrictions imposed by the Pauli Principle on allowed two electron states mean that the spin state of such systems has a profound impact on the orbital states (positions) of the electrons, a parameter which SET's are extremely well suited to measure. We focus on a particular system capable of being fabricated with current technology: a Te double donor in Si adjacent to a Si/SiO2 interface and lying directly beneath the SET island electrode, and we outline a measurement strategy capable of resolving single electron and nuclear spins in this system. We discuss the limitations of the measurement imposed by spin scattering arising from fluctuations emanating from the SET and from lattice phonons. We conclude that measurement of single spins, a necessary requirement for several proposed quantum computer architectures, is feasible in Si using this strategy.

  16. Light-Controlled Spin Filtering in Bacteriorhodopsin

    PubMed Central

    2015-01-01

    The role of the electron spin in chemistry and biology has received much attention recently owing to to the possible electromagnetic field effects on living organisms and the prospect of using molecules in the emerging field of spintronics. Recently the chiral-induced spin selectivity effect was observed by electron transmission through organic molecules. In the present study, we demonstrated the ability to control the spin filtering of electrons by light transmitted through purple membranes containing bacteriorhodopsin (bR) and its D96N mutant. The spin-dependent electrochemical cyclic voltammetry (CV) and chronoamperometric measurements were performed with the membranes deposited on nickel substrates. High spin-dependent electron transmission through the membranes was observed; however, after the samples were illuminated by 532 nm light, the spin filtering in the D96N mutant was dramatically reduced whereas the light did not have any effect on the wild-type bR. Beyond demonstrating spin-dependent electron transmission, this work also provides an interesting insight into the relationship between the structure of proteins and spin filtering by conducting electrons. PMID:25621438

  17. Attitude control of a spinning rocket via thrust vectoring

    SciTech Connect

    White, J.E.

    1990-12-19

    Two controllers are developed to provide attitude control of a spinning rocket that has a thrust vectoring capability. The first controller has a single-input/single-output design that ignores the gyroscopic coupling between the control channels. The second controller has a multi-input/multi-output structure that is specifically intended to account for the gyroscopic coupling effects. A performance comparison between the two approached is conducted for a range of roll rates. Each controller is tested for the ability to track step commands, and for the amount of coupling impurity. Both controllers are developed via a linear-quadratic-regulator synthesis procedure, which is motivated by the multi-input/multi-output nature of second controller. Time responses and a singular value analysis are used to evaluate controller performance. This paper describes the development and comparison of two controllers that are designed to provide attitude control of a spinning rocket that is equipped with thrust vector control. 12 refs., 13 figs., 2 tabs.

  18. Single Spin Asymmetries in the BRAHMS Experiment

    E-print Network

    F. Videbaek; for the BRAHMS collaboration

    2005-08-11

    The BRAHMS experiment at RHIC has the capability to measure the transverse spin asymmetries in polarized pp induced pion production at RHIC. The first results from the short run-4 show a signaificant asymmetry for pi-plus and pi-minus at moderate xF. The trend of the data is in agreement with lower energy data while the absolute value are surprisingly large.

  19. Attitude orientation control for a spinning satellite

    NASA Astrophysics Data System (ADS)

    Frost, Gerald

    The Department of the Air Force, Headquarters Space Systems Division, and the National Aeronautics and Space Administration (NASA) are currently involved in litigation with Hughes Aircraft Company over the alledged infringement of the 'Williams patent,' which describes a method for attitude control of a spin-stabilized vehicle. Summarized here is pre-1960 RAND work on this subject and information obtained from RAND personnel knowledgeable on this subject. It was concluded that there is no RAND documentation that directly parallels the 'Williams patent' concept. Also, the TIROS II magnetic torque attitude control method is reviewed. The TIROS II meteorological satellite, launched on November 23, 1960, incorporated a magnetic actuation system for spin axis orientation control. The activation system was ground controlled to orient the satellite spin axis to obtain the desired pointing direction for optical and infrared sensor subsystems.

  20. Cryogenic single-chip electron spin resonance detector

    NASA Astrophysics Data System (ADS)

    Gualco, Gabriele; Anders, Jens; Sienkiewicz, Andrzej; Alberti, Stefano; Forró, László; Boero, Giovanni

    2014-10-01

    We report on the design and characterization of a single-chip electron spin resonance detector, operating at a frequency of about 20 GHz and in a temperature range extending at least from 300 K down to 4 K. The detector consists of an LC oscillator formed by a 200 ?m diameter single turn aluminum planar coil, a metal-oxide-metal capacitor, and two metal-oxide-semiconductor field effect transistors used as negative resistance network. At 300 K, the oscillator has a frequency noise of 20 Hz/Hz1/2 at 100 kHz offset from the 20 GHz carrier. At 4 K, the frequency noise is about 1 Hz/Hz1/2 at 10 kHz offset. The spin sensitivity measured with a sample of DPPH is 108 spins/Hz1/2 at 300 K and down to 106 spins/Hz1/2 at 4 K.

  1. Efficient Readout of a Single Spin State in Diamond via Spin-to-Charge Conversion.

    PubMed

    Shields, B J; Unterreithmeier, Q P; de Leon, N P; Park, H; Lukin, M D

    2015-04-01

    Efficient readout of individual electronic spins associated with atomlike impurities in the solid state is essential for applications in quantum information processing and quantum metrology. We demonstrate a new method for efficient spin readout of nitrogen-vacancy (NV) centers in diamond. The method is based on conversion of the electronic spin state of the NV to a charge-state distribution, followed by single-shot readout of the charge state. Conversion is achieved through a spin-dependent photoionization process in diamond at room temperature. Using NVs in nanofabricated diamond beams, we demonstrate that the resulting spin readout noise is within a factor of 3 of the spin projection noise level. Applications of this technique for nanoscale magnetic sensing are discussed. PMID:25884129

  2. Observation of Spin Flips with a Single Trapped Proton

    SciTech Connect

    Ulmer, S. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany); Ruprecht Karls-Universitaet Heidelberg, D-69047 Heidelberg (Germany); Rodegheri, C. C. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany); Blaum, K. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Ruprecht Karls-Universitaet Heidelberg, D-69047 Heidelberg (Germany); Kracke, H.; Mooser, A.; Walz, J. [Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany); Helmholtz Institut Mainz, D-55099 Mainz (Germany); Quint, W. [Ruprecht Karls-Universitaet Heidelberg, D-69047 Heidelberg (Germany); GSI--Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany)

    2011-06-24

    Radio-frequency induced spin transitions of one individual proton are observed. The spin quantum jumps are detected via the continuous Stern-Gerlach effect, which is used in an experiment with a single proton stored in a cryogenic Penning trap. This is an important milestone towards a direct high-precision measurement of the magnetic moment of the proton and a new test of the matter-antimatter symmetry in the baryon sector.

  3. Hall magnetometry of micromagnets for single-electron spin qubits

    NASA Astrophysics Data System (ADS)

    Lachance-Quirion, Dany; Camirand Lemyre, Julien; Bergeron, Laurent; Pioro-Ladrière, Michel

    2015-03-01

    The coherence time of a single-electron spin can reach tens of milliseconds when placed in the right environment. The electric-dipole interaction between such a single spin and an electric field can be engineered by the inhomogeneous magnetic field of a micromagnet. This effective spin-orbit interaction can be used to manipulate the spin through electric-dipole spin resonance, but also to couple a single spin to the electric field of a microwave cavity in the circuit QED architecture. We selected the material and improved the shape of the micromagnet in order to maximize magnetic field gradients and remanence. We perform Hall magnetometry of those improved micromagnets using Hall bars electrostatically defined in an AlGaAs/GaAs two-dimensional electron gas. The gate-voltage dependent width of the Hall bar enables us to map the averaged magnetic field of the micromagnet, which validates simulations of the inhomogeneous magnetic field profile created by the magnet. We can therefore deduce that our micromagnets can produce magnetic field differences over 200 nm of more than 200 mT.

  4. Spin-transfer torque in a single ferromagnet

    NASA Astrophysics Data System (ADS)

    Ji, Yi

    2004-03-01

    A spin polarized current, with sufficiently high current density, is able to switch a magnet or induce magnetization precession. This is the consequence of the ¡°spin-transfer torque¡+/- that originates from spin angular momentum transfer between conduction electrons and the magnetization. Previously most theories and experiments explore F/N/F trilayer and F/N multilayer structures, where F denotes a ferromagnet and N denotes a nonmagnetic metal. These structures have been generally presumed indispensable, since non-collinear magnetizations between a polarizing layer and a free layer are required to generate spin torques, and the GMR effect is essential in detecting magnetization variations. In this work, spin-transfer torque effects in a single ferromagnetic layer are demonstrated, using current injection through a point-contact at 4.2 K. Firstly, differential resistance peaks, generally regarded as signatures of spin-wave excitations, are observed in a single ferromagnetic layer in high magnetic fields [1]. The current values corresponding to the peak positions linearly depend on the external field in the range of 2 to 9 Tesla. Secondly, hysteretic current-induced switching is observed in a single ferromagnet in low magnetic fields. Both experiments can be interpreted by a simple model based on heterogeneous current distribution and domain wall scattering. Systematic variations between low field and high field regions have been investigated and the implications will be discussed. [1] Y. Ji, C. L. Chien and M. D. Stiles, Phys. Rev. Lett. 90, 106601 (2003)

  5. Single-spin observables and orbital structures in hadronic distributions

    NASA Astrophysics Data System (ADS)

    Sivers, Dennis

    2006-11-01

    Single-spin observables in scattering processes (either analyzing powers or polarizations) are highly constrained by rotational invariance and finite symmetries. For example, it is possible to demonstrate that all single-spin observables are odd under the finite transformation O=PA? where P is parity and A? is a finite symmetry that can be designated “artificial time reversal”. The operators P, O and A? all have eigenvalues ±1 so that all single-spin observables can be classified into two distinct categories: (1) P-odd and A?-even, (2) P-even and A?-odd. Within the light-quark sector of the standard model, P-odd observables are generated from pointlike electroweak processes while A?-odd observables (neglecting quark mass parameters) come from dynamic spin-orbit correlations within hadrons or within larger composite systems, such as nuclei. The effects of A?-odd dynamics can be inserted into transverse-momentum dependent constituent distribution functions and, in this paper, we construct the contribution from an orbital quark to the A?-odd quark parton distribution ?NGq/p?front(x,kTN;?2). Using this distribution, we examine the crucial role of initial- and final-state interactions in the observation of the scattering asymmetries in different hard-scattering processes. This construction provides a geometrical and dynamical interpretation of the Collins conjugation relation between single-spin asymmetries in semi-inclusive deep inelastic scattering and the asymmetries in Drell-Yan production. Finally, our construction allows us to display a significant difference between the calculation of a spin asymmetry generated by a hard-scattering mechanism involving color-singlet exchange (such as a photon) and a calculation of an asymmetry with a hard-scattering exchange involving gluons. This leads to an appreciation of the process-dependence inherent in measurements of single-spin observables.

  6. Single hadron transverse spin asymmetries from COMPASS

    SciTech Connect

    Bradamante, Franco [Trieste University, Trieste (Italy); INFN, Trieste (Italy)

    2007-06-13

    Transverse spin physics is an important part of the scientific programme of the COMPASS experiment at CERN. The analysis of the data taken with the target polarized orthogonally to the 160 GeV/c muon beam momentum has allowed to measure for the first time the Collins and Sivers asymmetries of the deuteron. Both for the positive and the negative hadrons produced in semi-inclusive DIS the measured asymmetries are small and, within errors, compatible with zero. New results for {pi}{+-} ans K{+-} are presented here.

  7. Single hadron transverse spin asymmetries from COMPASS

    E-print Network

    F. Bradamante

    2007-02-02

    Transverse spin physics is an important part of the scientific programme of the COMPASS experiment at CERN. The analysis of the data taken with the target polarized orthogonally to the 160 GeV/c muon beam momentum has allowed to measure for the first time the Collins and Sivers asymmetries of the deuteron. Both for the positive and the negative hadrons produced in semi-inclusive DIS the measured asymmetries are small and, within errors, compatible with zero. New results for charged pions and kaons are presented here.

  8. High spin rate magnetic controller for nanosatellites

    NASA Astrophysics Data System (ADS)

    Slavinskis, A.; Kvell, U.; Kulu, E.; Sünter, I.; Kuuste, H.; Lätt, S.; Voormansik, K.; Noorma, M.

    2014-02-01

    This paper presents a study of a high rate closed-loop spin controller that uses only electromagnetic coils as actuators. The controller is able to perform spin rate control and simultaneously align the spin axis with the Earth's inertial reference frame. It is implemented, optimised and simulated for a 1-unit CubeSat ESTCube-1 to fulfil its mission requirements: spin the satellite up to 360 deg s-1 around the z-axis and align its spin axis with the Earth's polar axis with a pointing error of less than 3°. The attitude of the satellite is determined using a magnetic field vector, a Sun vector and angular velocity. It is estimated using an Unscented Kalman Filter and controlled using three electromagnetic coils. The algorithm is tested in a simulation environment that includes models of space environment and environmental disturbances, sensor and actuator emulation, attitude estimation, and a model to simulate the time delay caused by on-board calculations. In addition to the normal operation mode, analyses of reduced satellite functionality are performed: significant errors of attitude estimation due to non-operational Sun sensors; and limited actuator functionality due to two non-operational coils. A hardware-in-the-loop test is also performed to verify on-board software.

  9. Excited-state spectroscopy using single-spin manipulation in diamond

    E-print Network

    G. D. Fuchs; V. V. Dobrovitski; R. Hanson; A. Batra; C. D. Weis; T. Schenkel; D. D. Awschalom

    2008-06-11

    We use single-spin resonant spectroscopy to study the spin structure in the orbital excited-state of a diamond nitrogen-vacancy center at room temperature. We find that the excited state spin levels have a zero-field splitting that is approximately half of the value of the ground state levels, a g-factor similar to the ground state value, and a hyperfine splitting ~20x larger than in the ground state. In addition, the width of the resonances reflects the electronic lifetime in the excited state. We also show that the spin-splitting can significantly differ between NV centers, likely due to the effects of local strain, which provides a pathway to control over the spin Hamiltonian and may be useful for quantum information processing.

  10. Single-Transverse Spin Asymmetries: From DIS to Hadronic Collisions

    E-print Network

    Werner Vogelsang; Feng Yuan

    2005-09-28

    We study single-spin asymmetries in semi-inclusive deep inelastic scattering with transversely polarized target. Based on the QCD factorization approach, we consider Sivers and Collins contributions to the asymmetries. We fit simple parameterizations for the Sivers and Collins functions to the recent HERMES data, and compare to results from COMPASS. Using the fitted parameterizations for the Sivers functions, we predict the single transverse spin asymmetries for various processes in $pp$ collisions at RHIC, including the Drell-Yan process and angular correlations in dijet and jet-plus-photon production. These asymmetries are found to be sizable at forward rapidities

  11. Single-Spin Asymmetries and Transversity in QCD

    SciTech Connect

    Brodsky, S.J.; /SLAC

    2005-12-14

    Initial- and final-state interactions from gluon exchange, normally neglected in the parton model, have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, as well as nuclear shadowing and antishadowing-leading-twist physics not incorporated in the light-front wavefunctions of the target computed in isolation. The physics of such processes thus require the understanding of QCD at the amplitude level; in particular, the physics of spin requires an understanding of the phase structure of final-state and initial-state interactions, as well as the structure of the basic wavefunctions of hadrons themselves. I also discuss transversity in exclusive channels, including how one can use single-spin asymmetries to determine the relative phases of the timelike baryon form factors, as well as the anomalous physics of the normal-normal spin-spin correlation observed in large-angle proton-proton elastic scattering. As an illustration of the utility of light-front wavefunctions, the transversity distribution of a single electron is computed, as defined from its two-particle QED quantum fluctuations.

  12. Gaussian approximation and single-spin measurement in magnetic resonance force microscopy with spin noise

    SciTech Connect

    Raghunathan, Shesha; Brun, Todd A. [Center for Quantum Information Science and Technology, Communication Sciences Institute, Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Goan, Hsi-Sheng [Department of Physics and Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Center for Quantum Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2010-11-15

    A promising technique for measuring single electron spins is magnetic resonance force microscopy (MRFM), in which a microcantilever with a permanent magnetic tip is resonantly driven by a single oscillating spin. The most effective experimental technique is the oscillating cantilever-driven adiabatic reversals (OSCAR) protocol, in which the signal takes the form of a frequency shift. If the quality factor of the cantilever is high enough, this signal will be amplified over time to the point where it can be detected by optical or other techniques. An important requirement, however, is that this measurement process occurs on a time scale that is short compared to any noise which disturbs the orientation of the measured spin. We describe a model of spin noise for the MRFM system and show how this noise is transformed to become time dependent in going to the usual rotating frame. We simplify the description of the cantilever-spin system by approximating the cantilever wave function as a Gaussian wave packet and show that the resulting approximation closely matches the full quantum behavior. We then examine the problem of detecting the signal for a cantilever with thermal noise and spin with spin noise, deriving a condition for this to be a useful measurement.

  13. Matrix Formalism for Spin Dynamics Near a Single Depolarization Resonance

    SciTech Connect

    Chao, Alexander W.; /SLAC

    2005-10-26

    A matrix formalism is developed to describe the spin dynamics in a synchrotron near a single depolarization resonance as the particle energy (and therefore its spin precession frequency) is varied in a prescribed pattern as a function of time such as during acceleration. This formalism is first applied to the case of crossing the resonance with a constant crossing speed and a finite total step size, and then applied also to other more involved cases when the single resonance is crossed repeatedly in a prescribed manner consisting of linear ramping segments or sudden jumps. How repeated crossings produce an interference behavior is discussed using the results obtained. For a polarized beam with finite energy spread, a spin echo experiment is suggested to explore this interference effect.

  14. Attitude orientation control for a spinning satellite

    Microsoft Academic Search

    Gerald Frost

    1991-01-01

    The Department of the Air Force, Headquarters Space Systems Division, and the National Aeronautics and Space Administration (NASA) are currently involved in litigation with Hughes Aircraft Company over the alledged infringement of the 'Williams patent,' which describes a method for attitude control of a spin-stabilized vehicle. Summarized here is pre-1960 RAND work on this subject and information obtained from RAND

  15. Charge and spin pumping effects in a single-dot Aharonov-Bohm ring with ferromagnetic leads

    NASA Astrophysics Data System (ADS)

    Pan, Hui; Xu, Huai-Zhe; Lü, Rong

    2010-11-01

    The pumping of electrons through a single-dot Aharonov-Bohm ring attached to ferromagnetic leads are investigated theoretically by using the nonequilibrium Green's function method. It is found that the charge and spin pumping effects at zero-bias voltage can be produced by an oscillating electric field applied to the quantum dot. The pumped charge and spin currents through the single-dot ring are analyzed for two cases: (i) the single-dot ring is connected with two ferromagnetic leads and (ii) the single-dot ring is connected with a ferromagnetic and a normal-metal lead. For the former case, a pure spin current can be generated due to the photon-assisted tunneling effects. For the latter case, both the charge and spin current can be pumped in opposite directions. The control of the pumped spin and charge current by using the magnetic flux through the ring is also discussed.

  16. Single-shot readout of spin qubits in Si/SiGe quantum dots

    NASA Astrophysics Data System (ADS)

    Simmons, Christie

    2012-02-01

    Si/SiGe quantum dots are an attractive option for spin qubit development, because of the long coherence times for electron spins in silicon, arising from weak hyperfine interaction and low spin orbit coupling. I will present measurements of gate-defined single and double quantum dots formed in Si/SiGe semiconductor heterostuctures. Control of the gate voltages on these dots enables tuning of the tunnel coupling to the leads and to other dots. Careful tuning of these tunnel rates, in combination with fast, pulsed-gate manipulation and spin-to-charge conversion, allow spin state measurement using an integrated quantum point contact as a local charge detector. Single spin qubit readout relies on the Zeeman energy splitting from an external magnetic field for spin-to-charge conversion. Two-electron singlet-triplet qubits, on the other hand, can be measured by using Pauli spin blockade of tunneling between the dots to readout the qubit even at zero magnetic field. I will present real-time, single-shot readout measurements of both individual spin [1] and singlet-triplet qubits [2] in gated Si/SiGe quantum dots. Work performed in collaboration with J. R. Prance, Zhan Shi, B. J. Van Bael, Teck Seng Koh, D. E. Savage, M. G. Lagally, R. Joynt, L. R. Schreiber, L. M. K. Vandersypen, M. Friesen, S. N. Coppersmith, and M. A. Eriksson. [4pt] [1] C. B. Simmons et al. Physical Review Letters 106, 156804 (2011). [0pt] [2] J. R. Prance, et al., e-print: http://lanl.arxiv.org/abs/1110.6431

  17. Dynamic strain-mediated coupling of a single diamond spin to a mechanical resonator.

    PubMed

    Ovartchaiyapong, Preeti; Lee, Kenneth W; Myers, Bryan A; Jayich, Ania C Bleszynski

    2014-01-01

    The development of hybrid quantum systems is central to the advancement of emerging quantum technologies, including quantum information science and quantum-assisted sensing. The recent demonstration of high-quality single-crystal diamond resonators has led to significant interest in a hybrid system consisting of nitrogen-vacancy centre spins that interact with the resonant phonon modes of a macroscopic mechanical resonator through crystal strain. However, the nitrogen-vacancy spin-strain interaction has not been well characterized. Here, we demonstrate dynamic, strain-mediated coupling of the mechanical motion of a diamond cantilever to the spin of an embedded nitrogen-vacancy centre. Via quantum control of the spin, we quantitatively characterize the axial and transverse strain sensitivities of the nitrogen-vacancy ground-state spin. The nitrogen-vacancy centre is an atomic scale sensor and we demonstrate spin-based strain imaging with a strain sensitivity of 3 × 10(-6) strain Hz(-1/2). Finally, we show how this spin-resonator system could enable coherent spin-phonon interactions in the quantum regime. PMID:25034828

  18. Room temperature entanglement between distant single spins in diamond

    E-print Network

    Florian Dolde; Ingmar Jakobi; Boris Naydenov; Nan Zhao; Sebastien Pezzagna; Christina Trautmann; Jan Meijer; Philipp Neumann; Fedor Jelezko; Jörg Wrachtrup

    2012-12-12

    Entanglement is the central yet fleeting phenomena of quantum physics. Once being considered a peculiar counter-intuitive property of quantum theory it has developed into the most central element of quantum technology providing speed up to quantum computers, a path towards long distance quantum cryptography and increased sensitivity in quantum metrology. Consequently, there have been a number of experimental demonstration of entanglement between photons, atoms, ions as well as solid state systems like spins or quantum dots, superconducting circuits and macroscopic diamond. Here we experimentally demonstrate entanglement between two engineered single solid state spin quantum bits (qubits) at ambient conditions. Photon emission of defect pairs reveals ground state spin correlation. Entanglement (fidelity = 0.67 \\pm 0.04) is proven by quantum state tomography. Moreover, the lifetime of electron spin entanglement is extended to ms by entanglement swapping to nuclear spins, demonstrating nuclear spin entanglement over a length scale of 25 nm. The experiments mark an important step towards a scalable room temperature quantum device being of potential use in quantum information processing as well as metrology.

  19. Harnessing the GaAs quantum dot nuclear spin bath for quantum control

    E-print Network

    Hugo Ribeiro; J. R. Petta; Guido Burkard

    2011-12-20

    We theoretically demonstrate that nuclear spins can be harnessed to coherently control two-electron spin states in a double quantum dot. Hyperfine interactions lead to an avoided crossing between the spin singlet state and the ms = +1 triplet state, T_+ . We show that a coherent superposition of singlet and triplet states can be achieved using finite-time Landau-Zener-St\\"uckelberg interferometry. In this system the coherent rotation rate is set by the Zeeman energy, resulting in ~1 nanosecond single spin rotations. We analyze the coherence of this spin qubit by considering the coupling to the nuclear spin bath and show that T_2^* ~ 16 ns, in good agreement with experimental data. Our analysis further demonstrates that efficient single qubit and two qubit control can be achieved using Landau-Zener-St\\"uckelberg interferometry.

  20. Single-proton spin detection by diamond magnetometry.

    PubMed

    Loretz, M; Rosskopf, T; Boss, J M; Pezzagna, S; Meijer, J; Degen, C L

    2014-10-16

    Extending magnetic resonance imaging to the atomic scale has been a long-standing aspiration, driven by the prospect of directly mapping atomic positions in molecules with three-dimensional spatial resolution. We report detection of individual, isolated proton spins by a nitrogen-vacancy (NV) center in a diamond chip covered by an inorganic salt. The single-proton identity was confirmed by the Zeeman effect and by a quantum coherent rotation of the weakly coupled nuclear spin. Using the hyperfine field of the NV center as an imaging gradient, we determined proton-NV distances of less than 1 nm. PMID:25323696

  1. Photoelectron spin-polarization control in the topological insulator Bi2Se3.

    PubMed

    Zhu, Z-H; Veenstra, C N; Zhdanovich, S; Schneider, M P; Okuda, T; Miyamoto, K; Zhu, S-Y; Namatame, H; Taniguchi, M; Haverkort, M W; Elfimov, I S; Damascelli, A

    2014-02-21

    We study the manipulation of the spin polarization of photoemitted electrons in Bi2Se3 by spin- and angle-resolved photoemission spectroscopy. General rules are established that enable controlling the photoelectron spin-polarization. We demonstrate the ±?100% reversal of a single component of the measured spin-polarization vector upon the rotation of light polarization, as well as full three-dimensional manipulation by varying experimental configuration and photon energy. While a material-specific density-functional theory analysis is needed for the quantitative description, a minimal yet fully generalized two-atomic-layer model qualitatively accounts for the spin response based on the interplay of optical selection rules, photoelectron interference, and topological surface-state complex structure. It follows that photoelectron spin-polarization control is generically achievable in systems with a layer-dependent, entangled spin-orbital texture. PMID:24579623

  2. Single-chip detector for electron spin resonance spectroscopy.

    PubMed

    Yalcin, T; Boero, G

    2008-09-01

    We have realized an innovative integrated detector for electron spin resonance spectroscopy. The microsystem, consisting of an LC oscillator, a mixer, and a frequency division module, is integrated onto a single silicon chip using a conventional complementary metal-oxide-semiconductor technology. The implemented detection method is based on the measurement of the variation of the frequency of the integrated LC oscillator as a function of the applied static magnetic field, caused by the presence of a resonating sample placed over the inductor of the LC-tank circuit. The achieved room temperature spin sensitivity is about 10(10) spinsGHz(12) with a sensitive volume of about (100 microm)(3). PMID:19044436

  3. Electrical control of spin in topological insulators

    NASA Astrophysics Data System (ADS)

    Chang, Kai

    2012-02-01

    All-electrical manipulation of electron spin in solids becomes a central issue of quantum information processing and quantum computing. The many previous proposals are based on spin-orbit interactions in semiconductors. Topological insulator, a strong spin-orbit coupling system, make it possible to control the spin transport electrically. Recent calculations proved that external electric fields can drive a HgTe quantum well from normal band insulator phase to topological insulator phase [1]. Since the topological edge states are robust against local perturbation, the controlling of edge states using local fields is a challenging task. We demonstrate that a p-n junction created electrically in HgTe quantum wells with inverted band structure exhibits interesting intraband and interband tunneling processes. We find a perfect intraband transmission for electrons injected perpendicularly to the interface of the p-n junction. The opacity and transparency of electrons through the p-n junction can be tuned by changing the incidence angle, the Fermi energy and the strength of the Rashba spin-orbit interaction (RSOI). The occurrence of a conductance plateau due to the formation of topological edge states in a quasi-one-dimensional p-n junction can be switched on and off by tuning the gate voltage. The spin orientation can be substantially rotated when the samples exhibit a moderately strong RSOI [2]. An electrical switching of the edge-state transport can also be realized using quantum point contacts in quantum spin Hall bars. The switch-on/off of the edge channel is caused by the finite size effect of the quantum point contact and therefore can be manipulated by tuning the voltage applied on the split gate [3,4]. The magnetic ions doped on the surface of 3D TI can be correlated through the helical electrons. The RKKY interaction mediated by the helical Dirac electrons consists of the Heisenberg-like, Ising-like, and Dzyaloshinskii-Moriya (DM)-like terms, which can be tuned by changing the gate voltage. It provides us a new way to control surface magnetism electrically. The gap opened by doped magnetic ions can lead to a short-range Bloembergen-Rowland interaction. The competition among the Heisenberg, Ising, and DM terms leads to rich spin configurations and an anomalous Hall effect on different lattices [4]. There are many proposals for quantum computation scheme are based on the spin in semiconductor quantum dots. Topological insulator quantum dots display a very different behavior with that of conventional semiconductor quantum dots [5]. In sharp contrast to conventional semiconductor quantum dots, the quantum states in the gap of the HgTe QD are fully spin-polarized and show ring-like density distributions near the boundary of the QD and optically dark. The persistent charge currents and magnetic moments, i.e., the Aharonov-Bohm effect, can be observed in such a QD structure. This feature offers us a practical way to detect these exotic ring-like edge states by using the SQUID technique. [0pt]Refs: [1] W. Yang, Kai Chang, and S. C. Zhang, Phys. Rev. Lett. 100, 056602 (2008); J. Li and Kai Chang, Appl. Phys. Lett. 95, 222110 (2009). [2] L. B. Zhang, Kai Chang, X. C. Xie, H. Buhmann and L. W. Molenkamp, New J. Phys. 12, 083058 (2010). [3] L. B. Zhang, F. Cheng, F. Zhai and Kai Chang, Phys. Rev. B 83 081402(R) (2011); Z. H. Wu, F. Zhai, F. M. Peeters, H. Q. Xu and Kai Chang, Phys, Rev. Lett. 106, 176802 (2011). [4] J. J. Zhu, D. X. Yao, S. C. Zhang, and Kai Chang, Phys. Rev. Lett. 106, 097201 (2011). [5] Kai Chang, and Wen-Kai Lou, Phys. Rev. Lett. 106, 206802 (2011).

  4. Long-range spin-triplet correlations and edge spin currents in diffusive spin-orbit coupled SNS hybrids with a single spin-active interface.

    PubMed

    Alidoust, Mohammad; Halterman, Klaus

    2015-06-17

    Utilizing a SU(2) gauge symmetry technique in the quasiclassical diffusive regime, we theoretically study finite-sized two-dimensional intrinsic spin-orbit coupled superconductor/normal-metal/superconductor (S/N/S) hybrid structures with a single spin-active interface. We consider intrinsic spin-orbit interactions (ISOIs) that are confined within the N wire and absent in the s-wave superconducting electrodes (S). Using experimentally feasible parameters, we demonstrate that the coupling of the ISOIs and spin moment of the spin-active interface results in maximum singlet-triplet conversion and accumulation of spin current density at the corners of the N wire nearest the spin-active interface. By solely modulating the superconducting phase difference, we show how the opposing parities of the charge and spin currents provide an effective venue to experimentally examine pure edge spin currents not accompanied by charge currents. These effects occur in the absence of externally imposed fields and moreover are insensitive to the arbitrary orientations of the interface spin moment. The experimental implementation of these robust edge phenomena are also discussed. PMID:25996592

  5. Long-range spin-triplet correlations and edge spin currents in diffusive spin–orbit coupled SNS hybrids with a single spin-active interface

    NASA Astrophysics Data System (ADS)

    Alidoust, Mohammad; Halterman, Klaus

    2015-06-01

    Utilizing a SU(2) gauge symmetry technique in the quasiclassical diffusive regime, we theoretically study finite-sized two-dimensional intrinsic spin–orbit coupled superconductor/normal-metal/superconductor (S/N/S) hybrid structures with a single spin-active interface. We consider intrinsic spin–orbit interactions (ISOIs) that are confined within the N wire and absent in the s-wave superconducting electrodes (S). Using experimentally feasible parameters, we demonstrate that the coupling of the ISOIs and spin moment of the spin-active interface results in maximum singlet-triplet conversion and accumulation of spin current density at the corners of the N wire nearest the spin-active interface. By solely modulating the superconducting phase difference, we show how the opposing parities of the charge and spin currents provide an effective venue to experimentally examine pure edge spin currents not accompanied by charge currents. These effects occur in the absence of externally imposed fields and moreover are insensitive to the arbitrary orientations of the interface spin moment. The experimental implementation of these robust edge phenomena are also discussed.

  6. Excited-state spin coherence of a single nitrogen-vacancy centre in diamond

    NASA Astrophysics Data System (ADS)

    Fuchs, G. D.; Dobrovitski, V. V.; Toyli, D. M.; Heremans, F. J.; Weis, C. D.; Schenkel, T.; Awschalom, D. D.

    2010-09-01

    Nitrogen-vacancy centres in diamond are a solid-state analogue of trapped atoms, with fine structure in both the ground and excited states that may be used for advanced quantum control. These centres are promising candidates for spin-based quantum information processing and magnetometry at room temperature. Knowledge of the excited-state (ES) structure and coherence is critical to evaluating the ES as a room-temperature quantum resource, for example for a fast, optically gated swap operation with a nuclear-spin memory. Here we report experiments that probe the ES-spin coherence of single nitrogen-vacancy centres. Using a combination of pulsed-laser excitation and nanosecond-scale microwave manipulation, we observed ES Rabi oscillations, and multipulse resonant control enabled us to study coherent ES electron/nuclear-spin interactions. To understand these processes, we developed a finite-temperature theory of ES spin dynamics that also provides a pathway towards engineering longer ES spin coherence.

  7. Nanomechanical single-qubit gates and iSWAP gate of single-electron spins in a carbon nanotube

    NASA Astrophysics Data System (ADS)

    Wang, Heng; Burkard, Guido

    2015-03-01

    A universal gate set for quantum computation can be built with one-qubit and iSWAP gates. We theoretically investigate mechanically-induced single-electron spin resonance in a quantum dot and a phonon mediated iSWAP gate of two separate single electron spins in two quantum dots on a suspended carbon nanotube which is driven by an external electric field. The intrinsic spin-phonon coupling between the spin and the mechanical mode is induced by the spin-orbit coupling. Arbitrary-angle rotations about arbitrary axes of the single electron spin can be achieved by varying the frequency and the strength of the external electric driving field. If two single-electron spins in two quantum dots couple to the same vibrational mode simultaneously, the two spins are indirectly coupled via phonon exchange. Both electron spin resonance and the iSWAP gate can be turned off by suppressing the spin-phonon coupling by electrostatically shifting the electron wave function on the nanotube. Combining iSWAP and single spin gates, maximally entangled states of two spins can be generated in a single step.

  8. Quantifying the quantum gate fidelity of single-atom spin qubits in silicon by randomized benchmarking

    E-print Network

    J. T. Muhonen; A. Laucht; S. Simmons; J. P. Dehollain; R. Kalra; F. E. Hudson; S. Freer; K. M. Itoh; D. N. Jamieson; J. C. McCallum; A. S. Dzurak; A. Morello

    2014-10-09

    Building upon the demonstration of coherent control and single-shot readout of the electron and nuclear spins of individual 31-P atoms in silicon, we present here a systematic experimental estimate of quantum gate fidelities using randomized benchmarking of 1-qubit gates in the Clifford group. We apply this analysis to the electron and the ionized 31-P nucleus of a single P donor in isotopically purified 28-Si. We find average gate fidelities of 99.95 % for the electron, and 99.99 % for the nuclear spin. These values are above certain error correction thresholds, and demonstrate the potential of donor-based quantum computing in silicon. By studying the influence of the shape and power of the control pulses, we find evidence that the present limitation to the gate fidelity is mostly related to the external hardware, and not the intrinsic behaviour of the qubit.

  9. Rotary balance data for a typical single-engine general aviation design for an angle-of-attack range of 20 to 90 deg. 3: Influence of control deflection on predicted model D spin modes

    NASA Technical Reports Server (NTRS)

    Ralston, J. N.; Barnhart, B. P.

    1984-01-01

    The influence of control deflections on the rotational flow aerodynamics and on predicted spin modes is discussed for a 1/6-scale general aviation airplane model. The model was tested for various control settings at both zero and ten degree sideslip angles. Data were measured, using a rotary balance, over an angle-of-attack range of 30 deg to 90 deg, and for clockwise and counter-clockwise rotations covering an omegab/2V range of 0 to 0.5.

  10. Spin Anisotropy Effects in Dimer Single Molecule Magnets

    NASA Astrophysics Data System (ADS)

    Efremov, Dmitri; Klemm, Richard

    2006-03-01

    We present a model of equal spin s1 dimer single molecule magnets. The spins within each dimer interact via the Heisenberg and the most general set of four quadratic anisotropic spin interactions with respective strengths J and Jj, and with the magnetic induction B. For antiferromagnetic Heisenberg couplings (J<0) and weak anisotropy interactions (|Jj/J|1), the low temperature T magnetization M(B) exhibits 2s1 steps, the height and midpoint slope of the sth step differing from their isotropic limits by corrections of O(Jj/J)^2, but the position occurring at the energy level-crossing magnetic induction Bs,s1^lc(,), where , define the direction of B. We solve the model exactly for s1=1/2, 1, and 5/2. For weakly anisotropic dimers, the Hartree approximation yields analytic formulas for M(B) and CV(B) at arbitrary s1 that accurately fit the exact solutions at sufficiently low T or large B. Low-T formulas for the inelastic neutron scattering S(q,?) and the EPR ?(?) in an extended Hartree approximation are given. Our results are discussed with regard to existing experiments on s1=5/2 Fe2 dimers, suggesting further experiments on single crystals of these and some s1=9/2 [Mn4]2 dimers are warranted.

  11. Bang-Bang control of a qubit coupled to a quantum critical spin bath

    E-print Network

    Davide Rossini; Paolo Facchi; Rosario Fazio; Giuseppe Florio; Daniel A. Lidar; Saverio Pascazio; Francesco Plastina; Paolo Zanardi

    2008-05-20

    We analytically and numerically study the effects of pulsed control on the decoherence of a qubit coupled to a quantum spin bath. When the environment is critical, decoherence is faster and we show that the control is relatively more effective. Two coupling models are investigated, namely a qubit coupled to a bath via a single link and a spin star model, yielding results that are similar and consistent.

  12. Single-spin measurement using single-electron transistors to probe two-electron systems

    Microsoft Academic Search

    B. E. Kane; N. S. McAlpine; A. S. Dzurak; R. G. Clark; G. J. Milburn; He Bi Sun; Howard Wiseman

    2000-01-01

    We present a method for measuring single spins embedded in a solid by probing\\u000atwo electron systems with a single electron transistor (SET). Restrictions\\u000aimposed by the Pauli Principle on allowed two electron states mean that the\\u000aspin state of such systems has a profound impact on the orbital states\\u000a(positions) of the electrons, a parameter which SET's are extremely

  13. Coherent control over diamond nitrogen-vacancy center spins with a mechanical resonator

    NASA Astrophysics Data System (ADS)

    Fuchs, Gregory

    2015-03-01

    We demonstrate coherent Rabi oscillations of diamond nitrogen-vacancy (NV) center spins driven directly by a mechanical resonator without mediation by a magnetic driving field. Using a bulk-mode acoustic resonator fabricated from single crystal diamond, we exert non-axial ac stress on NV centers positioned at an antinode of a gigahertz frequency mechanical mode. When the ?ms = -1 to +1 spin state splitting energy is tuned into resonance with a driven mechanical mode, we observe ?ms = +/-2 spin transitions, which are forbidden by the magnetic dipole selection rule. To rule out stray electric and magnetic fields as the origin of these spin transitions, we study the spin signal as a function depth within the diamond resonator. We find that the spin signal reproduces the periodicity of the acoustic standing wave, confirming the mechanical origin of the observed spin resonance. Using single-crystal diamond mechanical resonators with fQ products of 2 ×1012 , we observe coherent mechanically driven Rabi oscillations up to 4 MHz. For ensembles of NV centers coupled to the resonator, we analyze Rabi oscillations and their dephasing with a combination of spatially inhomogeneous mechanical driving and fluctuating magnetic fields from a noisy spin environment. Additionally, we examine the coherence of mechanically controlled NV center qubits and compare it to the coherence of magnetically controlled spin qubits in the NV center ground state spin manifold. This work demonstrates direct and coherent coupling between NV center spins and resonator phonons, which has potential for NV-based metrology using hybrid spin-mechanical sensors, fundamental research into spin-phonon interactions at the nanoscale, and as a platform for hybrid spin-mechanical quantum systems. Funding from ONR is gratefully acknowledged. In collaboration with E. R. MacQuarrie, T. A. Gosavi, A. M. Moehle, N. R. Jungwirth, and S. A. Bhave.

  14. COMPASS Results on Transverse Single-Spin Asymmetries

    E-print Network

    Anna Martin

    2007-02-01

    New results on single spin asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarised LiD target are presented. The data were taken in the years 2002, 2003 and 2004 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. Preliminary results are given for the Sivers asymmetry and for all the three ``quark polarimeters'' presently used in COMPASS to measure the transversity distributions. The Collins and the Sivers asymmetries for charged hadrons turn out to be compatible with zero, within the small (~1%) statistical errors, at variance with the results from HERMES on a transversely polarised proton target. Similar results have been obtained for the two hadron asymmetries and for the Lambda polarisation. First attempts to describe the Collins and the Sivers asymmetries measured by COMPASS and HERMES allow to give a consistent picture of these transverse spin effects.

  15. Giant Spin Hall Effect in Single Photon Plasmonics

    E-print Network

    G. S. Agarwal; S. -A. Biehs

    2012-12-24

    We show the existence of a very large spin Hall effect of light (SHEL) in single photon plasmonics based on spontaneous emission and the dipole-dipole interaction initiated energy transfer (FRET) on plasmonic platforms. The spin orbit coupling inherent in Maxwell equations is seen in the conversion of sigma + photon to sigma - photon. The FRET is mediated by the resonant surface plasmons and hence we find very large SHEL. We present explicit results for SHEL on both graphene and metal films. We also study how the splitting of the surface plasmon on a metal film affects the SHEL. In contrast to most other works which deal with SHEL as correction to the paraxial results, we consider SHEL in the near field of dipoles which are far from paraxial.

  16. Controlling Magnetization using Spin Orbit Torque

    NASA Astrophysics Data System (ADS)

    Salahuddin, Sayeef

    2015-03-01

    Recently it has been shown that spin orbit coupling (SOC) and/or broken inversion symmetry in vertical heterostructures can generate accumulation of spins when a charge current is flowing through them. In doing so, it can exert a torque on an adjacent magnet. Indeed, high Z metals (Ta, Pt, W, etc.) with strong SOC have been used to inject spin currents into adjacent ferromagnetic layers and thereby to induce magnetic switching, oscillation, domain wall movement etc. SOC physics promises to significantly reduce the required current for current induced magnetic switching for next generation data-storage applications. In this presentation we shall discuss some of our recent work on SOC induced control of magnets with perpendicular magnetic anisotropy (PMA). A current flowing in-plane presents interesting symmetry problems with respect to a PMA magnet. We shall discuss how these symmetry relations can be utilized for switching of and domain wall movement in the PMA magnets. In addition to storage applications, we shall also discuss possibility of exploiting SOC for spintronic logic applications.

  17. Coherence and Control of Quantum Registers Based on Electronic Spin in a Nuclear Spin Bath

    E-print Network

    Hodges, Jonathan S.

    We consider a protocol for the control of few-qubit registers comprising one electronic spin embedded in a nuclear spin bath. We show how to isolate a few proximal nuclear spins from the rest of the bath and use them as ...

  18. Smooth optimal quantum control for robust solid state spin magnetometry

    E-print Network

    Tobias Nöbauer; Andreas Angerer; Björn Bartels; Michael Trupke; Stefan Rotter; Jörg Schmiedmayer; Florian Mintert; Johannes Majer

    2014-12-16

    Nitrogen-vacancy centers in diamond show great potential as magnetic, electric and thermal sensors which are naturally packaged in a bio-compatible material. In particular, NV-based magnetometers combine small sensor volumes with high sensitivities under ambient conditions. The practical operation of such sensors, however, requires advanced quantum control techniques that are robust with respect to experimental and material imperfections, control errors, and noise. Here, we present a novel approach that uses Floquet theory to efficiently generate smooth and simple quantum control pulses with tailored robustness properties. We verify their performance by applying them to a single NV center and by characterising the resulting quantum gate using quantum process tomography. We show how the sensitivity of NV-ensemble magnetometry schemes can be improved by up to two orders of magnitude by compensating for inhomogeneities in both the control field and the spin transition frequency. Our approach is ideally suited for a wide variety of quantum technologies requiring high-fidelity, robust control under tight bandwidth requirements, such as spin-ensemble based memories involving high-Q cavities.

  19. Measurement of the Berry Phase in a Single Solid-State Spin Qubit

    E-print Network

    Kai Zhang; Naufer M. Nusran; Bradley R. Slezak; M. V. Gurudev Dutt

    2015-04-10

    We present measurements of the Berry Phase in a single solid-state spin qubit associated with the nitrogen-vacancy center in diamond. Our results demonstrate the remarkable degree of coherent control achievable in the presence of a highly complex solid-state environment. We manipulate the spin qubit geometrically by careful application of microwave radiation that creates an effective rotating magnetic field, and observe the resulting phase via spin-echo interferometry. We find good agreement with Berry's predictions within experimental errors. We also investigated the role of the environment on the geometric phase, and observed that unlike other solid-state qubit systems, the dephasing was primarily dominated by fast radial fluctuations in the path.

  20. Single Spin Asymmetries of Identified Hadrons s = 62.4 and 200 GeV

    E-print Network

    Single Spin Asymmetries of Identified Hadrons in p +p at s = 62.4 and 200 GeV J.H. Lee and F, USA Measurements of xF -dependent single spin asymmetries of identified charged hadrons, ± , K± , p of transverse spin asymme- tries and Quantum Chromodynamical description of hadronic structure. 1 Introduction

  1. Coherent spin control by electrical manipulation of the magnetic anisotropy

    E-print Network

    Richard E George; James P Edwards; Arzhang Ardavan

    2012-10-22

    High-spin paramagnetic manganese defects in polar piezoelectric zinc oxide exhibit a simple almost axial anisotropy and phase coherence times of the order of a millisecond at low temperatures. The anisotropy energy is tunable using an externally applied electric field. This can be used to control electrically the phase of spin superpositions and to drive spin transitions with resonant microwave electric fields.

  2. Measurement of the spin diffusion rate of dipolar order in single crystal calcium fluoride

    E-print Network

    Boutis, Gregory Steven, 1975-

    2002-01-01

    This thesis reports on the first measurement of the spin diffusion rate of a two-spin correlated state, known as dipolar order, in a single crystal of calcium fluoride. The experimental results for the component of the ...

  3. Half-metallic properties, single-spin negative differential resistance, and large single-spin Seebeck effects induced by chemical doping in zigzag-edged graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Yang, Xi-Feng; Zhou, Wen-Qian; Hong, Xue-Kun; Liu, Yu-Shen; Wang, Xue-Feng; Feng, Jin-Fu

    2015-01-01

    Ab initio calculations combining density-functional theory and nonequilibrium Green's function are performed to investigate the effects of either single B atom or single N atom dopant in zigzag-edged graphene nanoribbons (ZGNRs) with the ferromagnetic state on the spin-dependent transport properties and thermospin performances. A spin-up (spin-down) localized state near the Fermi level can be induced by these dopants, resulting in a half-metallic property with 100% negative (positive) spin polarization at the Fermi level due to the destructive quantum interference effects. In addition, the highly spin-polarized electric current in the low bias-voltage regime and single-spin negative differential resistance in the high bias-voltage regime are also observed in these doped ZGNRs. Moreover, the large spin-up (spin-down) Seebeck coefficient and the very weak spin-down (spin-up) Seebeck effect of the B(N)-doped ZGNRs near the Fermi level are simultaneously achieved, indicating that the spin Seebeck effect is comparable to the corresponding charge Seebeck effect.

  4. Spin anisotropy effects in dimer single molecule magnets

    NASA Astrophysics Data System (ADS)

    Efremov, Dmitri V.; Klemm, Richard A.

    2006-08-01

    We present a model of homoionic, equal-spin s1 dimer single molecule magnets exhibiting D2h , C2v , or S2 molecular group symmetry, focusing upon the simplest D2h case. The spins within each dimer interact via the Heisenberg and the most general set of four quadratic anisotropic spin interactions with respective strengths J and {Jj} , and with the magnetic induction B . We solve the model exactly for s1=1/2 , and analytically for B along the crystal directions and numerically for other B directions for s1=1 and 5/2, and present M(B) curves at low T for these cases with antiferromagnetic Heisenberg couplings (J<0) . Low- T CV(B) curves for s1=1/2 and electron paramagnetic susceptibility ?(B,?) for s1=1 are also provided. For weakly anisotropic dimers, the Hartree approximation, or strong exchange limit, yields rather simple analytic formulas for M(B) and CV(B) at arbitrary s1 that accurately fit the exact solutions at sufficiently low T or large B . Low- T , large- B formulas for the inelastic neutron-scattering cross section S(B,q,?) and ?(B,?) with arbitrary s1 and B in the Hartree approximation are also given. For antiferromagnetic Heisenberg couplings (J<0) and weak anisotropy interactions (?Jj/J??1) , we provide analytic formulas for the 2s1 level-crossing magnetic inductions Bs,s1lc(?,?) , at which the low- T magnetization M(B) exhibits steps and the low- T specific heat CV(B) exhibits zeroes, surrounded by double peaks of uniform height. Strong anisotropy interactions drastically alter these behaviors, however. Our results are discussed with regard to existing experiments on s1=5/2Fe2 , s1=3/2Cr2 , and s1=1Ni2 dimers, suggesting the presence of single-ion anisotropy in three of them, but apparently without any sizeable anisotropic exchange interactions. Further experiments on single crystals of these and higher-spin dimers are therefore warranted, and we particularly urge further electron paramagnetic resonance and inelastic neutron-scattering experiments to be performed.

  5. Entanglement Controlled Single-Electron Transmittivity

    E-print Network

    Francesco Ciccarello; Massimo Palma; Michelangelo Zarcone; Yasser Omar; Vitor Rocha Vieira

    2006-10-10

    We consider a system consisting of single electrons moving along a 1D wire in the presence of two magnetic impurities. Such system shows strong analogies with a Fabry - Perot interferometer in which the impurities play the role of two mirrors with a quantum degree of freedom: the spin. We have analysed the electron transmittivity of the wire in the presence of entanglement between the impurity spins. The main result of our analysis is that, for suitable values of the electron momentum, there are two maximally entangled state of the impurity spins the first of which makes the wire transparent whatever the electron spin state while the other strongly inhibits the electron transmittivity. Such predicted striking effect is experimentally observable with present day technology.

  6. Spin states in semiconductor quantum dot with a single magnetic ion

    NASA Astrophysics Data System (ADS)

    Li, X. J.; Yang, W.; Chang, Kai; Xia, J. B.

    2008-09-01

    We investigate theoretically CdTe quantum dots containing a single Mn impurity, including the sp-d exchange interaction between carriers and the magnetic ion and the short-range exchange interaction between electron and hole. We find anticrossing behaviors in the energy spectrum of the electron-hole (e-h) pair that arise from the interplay between exchange interactions and the magnetic field. In addition to the s-d exchange interaction, we find that other mechanisms inducing the anticrossings become important in the strong heavy hole-light hole ( hh- lh) mixing regime. The transition strengths between the states with spin projection of Mn ion Sz?-5/2 (Sz=-5/2) decrease (increase) with increasing magnetic fields due to the alignment of the Mn spin. The spin splitting of the e-h pair states depends sensitively on the external magnetic and electric field, which reveals useful information about the spin orientation and position of the magnetic ion. Meanwhile, the manipulation of the position of the magnetic ion offers us a way to control the spin splitting of the carriers.

  7. Controlling Spin-Spin Network Dynamics by Repeated Projective Measurements

    NASA Astrophysics Data System (ADS)

    Bretschneider, Christian O.; Álvarez, Gonzalo A.; Kurizki, Gershon; Frydman, Lucio

    2012-04-01

    We show that coupled-spin network manipulations can be made highly effective by repeated projections of the evolving quantum states onto diagonal density-matrix states (populations). As opposed to the intricately crafted pulse trains that are often used to fine-tune a complex network’s evolution, the strategy hereby presented derives from the “quantum Zeno effect” and provides a highly robust route to guide the evolution by destroying all unwanted correlations (coherences). We exploit these effects by showing that a relaxationlike behavior is endowed to polarization transfers occurring within a N-spin coupled network. Experimental implementations yield coupling constant determinations for complex spin-coupling topologies, as demonstrated within the field of liquid-state nuclear magnetic resonance.

  8. Magnetic ac control of the spin textures in a helical Luttinger liquid

    NASA Astrophysics Data System (ADS)

    Dolcetto, G.; Cavaliere, F.; Sassetti, M.

    2014-03-01

    We demonstrate the possibility to induce and control peculiar spin textures in a helical Luttinger liquid, by means of a time-dependent magnetic scatterer. The presence of a perturbation that breaks the time-reversal symmetry opens a gap in the spectrum, inducing single-particle backscattering and a peculiar spin response. We show that in the weak backscattering regime asymmetric spin textures emerge at the left and right sides of the scatterer, whose spatial oscillations are controlled by the ratio between the magnetization frequency and the Fermi energy and by the electron interaction. This peculiar spin response marks a strong difference between helical and nonhelical liquids, which are expected to produce symmetric spin textures even in the ac regime.

  9. Electrically controllable spin pumping in graphene via rotating magnetization

    NASA Astrophysics Data System (ADS)

    Rahimi, Mojtaba A.; Moghaddam, Ali G.

    2015-07-01

    We investigate pure spin pumping in graphene by imposing a ferromagnet (F) with rotating magnetization on top of it. Using the generalized scattering approach for adiabatic spin pumping, we obtain the spin current pumped through magnetic graphene to the normal (N) region. This spin current which can be easily controlled by gate voltages, reaches sufficiently large values measurable in current experimental setups. The spin current reaches its maximum when one of the spins is completely filtered because of its vanishing density of states in the ferromagnetic part. In order to study the effect of the ferromagnetic part length on the pumped spin current, the N—F—N structure is considered. It is found that in contrast to the metallic ferromagnetic materials the transverse spin coherence length can be comparable to the length of F. Subsequently, due to the quantum interferences inside the middle F region, the spin current becomes an oscillatory function of JL/\\hbar {{v}\\text{F}} in which J is the spin splitting and L is the length of F. Finally controllability of the pumped spin into two different normal sides in the N—F—N hybrid device gives rise to the spin battery effect.

  10. Nano-magnetic materials: spin crossover compounds vs. single molecule magnets vs. single chain magnets.

    PubMed

    Brooker, Sally; Kitchen, Jonathan A

    2009-09-28

    Brief introductions to spin crossover (SCO), single molecule magnetism (SMM) and single chain magnetism (SCM) are provided. Each section is illustrated by selected examples that have contributed significantly to the development of these fields, including recent efforts to produce materials (films, attachment to surfaces etc.). The advantages and disadvantages of each class of magnetically interesting compound are considered, along with the key challenges that remain to be overcome before such compounds can be used commercially as nanocomponents. This invited perspective article is intended to be easily comprehensible to non-specialists in the field. PMID:19727448

  11. Decoherence imaging of spin ensembles using a scanning single-electron spin in diamond

    PubMed Central

    Luan, Lan; Grinolds, Michael S.; Hong, Sungkun; Maletinsky, Patrick; Walsworth, Ronald L.; Yacoby, Amir

    2015-01-01

    The nitrogen-vacancy (NV) defect center in diamond has demonstrated great capability for nanoscale magnetic sensing and imaging for both static and periodically modulated target fields. However, it remains a challenge to detect and image randomly fluctuating magnetic fields. Recent theoretical and numerical works have outlined detection schemes that exploit changes in decoherence of the detector spin as a sensitive measure for fluctuating fields. Here we experimentally monitor the decoherence of a scanning NV center in order to image the fluctuating magnetic fields from paramagnetic impurities on an underlying diamond surface. We detect a signal corresponding to roughly 800??B in 2?s of integration time, without any control on the target spins, and obtain magnetic-field spectral information using dynamical decoupling techniques. The extracted spatial and temporal properties of the surface paramagnetic impurities provide insight to prolonging the coherence of near-surface qubits for quantum information and metrology applications. PMID:25631646

  12. Local probing of nuclear bath polarization with a single electronic spin

    E-print Network

    Paz London; Ran Fischer; Ignacio Alvizu; Jeronimo R. Maze; David Gershoni

    2015-05-22

    We demonstrate experimentally that a polarized nuclear spin modifies the dynamic behavior of a neighboring electronic spin. Specifically, an out-of-phase component appears in the electronic spin-echo signal. This component is proportional to the nuclear spin degree of polarization and strongly depends on the nuclear polarization direction. When the electronic spin is surrounded by a polarized nuclear spin bath, the spin-echo quadrature manifests a characteristic frequency related only to the nuclear spins abundance and their collective polarization. We use this analysis to propose a novel measurement method for the local nuclear spin bath of a single electronic spin. We quantify the realistic experimental regimes at which the scheme is efficient. Our proposal has potential applications for quantum sensing schemes, and opens a route for a systematic study of polarized mesoscopical-systems.

  13. Single-spin precessing gravitational waveform in closed form

    NASA Astrophysics Data System (ADS)

    Lundgren, Andrew; O'Shaughnessy, R.

    2014-02-01

    In coming years, gravitational-wave detectors should find black hole-neutron star (BH-NS) binaries, potentially coincident with astronomical phenomena like short gamma ray bursts. These binaries are expected to precess. Gravitational-wave science requires a tractable model for precessing binaries, to disentangle precession physics from other phenomena like modified strong field gravity, tidal deformability, or Hubble flow; and to measure compact object masses, spins, and alignments. Moreover, current searches for gravitational waves from compact binaries use templates where the binary does not precess and are ill-suited for detection of generic precessing sources. In this paper we provide a closed-form representation of the single-spin precessing waveform in the frequency domain by reorganizing the signal as a sum over harmonics, each of which resembles a nonprecessing waveform. This form enables simple analytic calculations of the Fisher matrix for use in template bank generation and coincidence metrics, and jump proposals to improve the efficiency of Markov chain Monte Carlo sampling. We have verified that for generic BH-NS binaries, our model agrees with the time-domain waveform to 2%. Straightforward extensions of the derivations outlined here (and provided in full online) allow higher accuracy and error estimates.

  14. Quasi-Classical Origins of Single Transverse Spin Asymmetries

    NASA Astrophysics Data System (ADS)

    Sievert, Matthew; Kovchegov, Yuri

    2013-10-01

    We consider semi-inclusive deep inelastic scattering and the Drell-Yan process on a transversely-polarized proton at high energies. We model the small- x wave function of the proton using the McLerran-Venugopalan (MV) model, which has been reasonably successful in describing high-energy proton data. The MV model, originally formulated for a heavy ion with a large number ~ A of independent color charges, is a quasi-classical description that should apply to any dense system of color charges, including a proton at very high energies. Here we incorporate spin dependence into the MV framework and analyze several microscopic scattering channels that lead to the generation of a single transverse spin asymmetry. In particular, we study asymmetries mediated by intrinsic orbital angular momentum, asymmetries produced locally by rescattering on the same constituent, and asymmetries that couple to the odderon. This analysis yields a simple, intuitive, quasi-classical picture in which one can understand understand the famous sign-reversal of the Sivers asymmetry between semi-inclusive deep inelastic scattering and the Drell-Yan process. Sponsored in part by DOE Grant No. DE-SC0004286.

  15. Global fitting of single spin asymmetry: an attempt

    SciTech Connect

    Alexey Prokudin,Zhong-Bo Kang

    2012-04-01

    We present an attempt of global analysis of Semi-Inclusive Deep Inelastic Scattering (SIDIS) $\\ell p^\\uparrow \\to \\ell' \\pi X$ data on single spin asymmetries and data on left-right asymmetry $A_N$ in $p^\\uparrow p \\to \\pi X$ in order to simultaneously extract information on Sivers function and twist-three quark-gluon Efremov-Teryaev-Qiu-Sterman (ETQS) function. We explore different possibilities such as node of Sivers function in $x$ or $k_\\perp$ in order to explain ``sign mismatch'' between these functions. We show that $\\pi^\\pm$ SIDIS data and $\\pi^0$ STAR data can be well described in a combined TMD and twist-3 fit, however $\\pi^\\pm$ BRAHMS data are not described in a satisfactory way. This leaves open a question to the solution of the ``sign mismatch''. Possible explanations are then discussed.

  16. Single Transverse-Spin Asymmetries at Large-x

    SciTech Connect

    Brodsky, Stanley J.; Yuan, Feng

    2006-10-24

    The large-x behavior of the transverse-momentum dependent quark distributions is analyzed in the factorization-inspired perturbative QCD framework, particularly for the naive time-reversal-odd quark Sivers function which is responsible for the single transverse-spin asymmetries in various semi-inclusive hard processes. By examining the dominant hard gluon exchange Feynman diagrams, and using the resulting power counting rule, we find that the Sivers function has power behavior (1-x){sup 4} at x {yields} 1, which is one power of (1-x) suppressed relative to the unpolarized quark distribution. These power-counting results provide important guidelines for the parameterization of quark distributions and quark-gluon correlations.

  17. Calculation of TMD Evolution for Transverse Single Spin Asymmetry Measurements

    SciTech Connect

    Mert Aybat, Ted Rogers, Alexey Prokudin

    2012-06-01

    In this letter, we show that it is necessary to include the full treatment of QCD evolution of Transverse Momentum Dependent parton densities to explain discrepancies between HERMES data and recent COMPASS data on a proton target for the Sivers transverse single spin asymmetry in Semi-Inclusive Deep Inelastic Scattering (SIDIS). Calculations based on existing fits to TMDs in SIDIS, and including evolution within the Collins-Soper-Sterman with properly defined TMD PDFs are shown to provide a good explanation for the discrepancy. The non-perturbative input needed for the implementation of evolution is taken from earlier analyses of unpolarized Drell-Yan (DY) scattering at high energy. Its success in describing the Sivers function in SIDIS data at much lower energies is strong evidence in support of the unifying aspect of the QCD TMD-factorization formalism.

  18. Magnetization process of a single magnetic ring detected by nonlocal spin valve measurement

    E-print Network

    Otani, Yoshichika

    Magnetization process of a single magnetic ring detected by nonlocal spin valve measurement T of a 200-nm-wide Permalloy ring using a nonlocal spin-valve measurement technique in a lateral geometry state using lateral spin-valve geometry.13­15 The chirality is found to be easily determined from

  19. One dimensional electron spin imaging for single spin detection and manipulation using a gradient field 

    E-print Network

    Shin, Chang-Seok

    2009-05-15

    and manipulate the spin states is also required for spin based quantum information processing. Although optical detection techniques, such as optically detected electron spin resonance (ESR) seem very powerful in these contexts, multiple molecules in the focal...

  20. Multiple Reflection Effect on Spin-Transfer Torque Dynamics in Spin Valves with a Single or Dual Polarizer

    NASA Astrophysics Data System (ADS)

    Zhu, Weiwei; Zhang, Zongzhi; Zhang, Jianwei; Liu, Yaowen

    2015-04-01

    In this paper, spin-dependent multiple reflection effect on spin-transfer torque (STT) has been theoretically and numerically studied in a spin valve nanopillar with a single or dual spin-polarizer. By using a scattering matrix method, we formulate an analytical expression of STT that contains the multiple interfacial reflection effect. It is found that the multiple reflections could enhance the STT efficiency and reduce the critical switching current. The STT efficiency depends on the spin polarization of both the free layer and polarizer. In the nanopillars with a dual spin polarizer, the multiple reflections would cause an asymmetric frequency dependence on the applied current, albeit exactly the same parameters are used in all three ferromagnetic layers, indicating that the frequency in the negative current varies much faster than that in the positive case.

  1. Electric control of spin in monolayer WSe? field effect transistors.

    PubMed

    Gong, Kui; Zhang, Lei; Liu, Dongping; Liu, Lei; Zhu, Yu; Zhao, Yonghong; Guo, Hong

    2014-10-31

    We report first-principles theoretical investigations of quantum transport in a monolayer WSe2 field effect transistor (FET). Due to strong spin-orbit interaction (SOI) and the atomic structure of the two-dimensional lattice, monolayer WSe2 has an electronic structure that exhibits Zeeman-like up-down spin texture near the K and K' points of the Brillouin zone. In a FET, the gate electric field induces an extra, externally tunable SOI that re-orients the spins into a Rashba-like texture thereby realizing electric control of the spin. The conductance of FET is modulated by the spin texture, namely by if the spin orientation of the carrier after the gated channel region, matches or miss-matches that of the FET drain electrode. The carrier current I(?, s) in the FET is labelled by both the valley index and spin index, realizing valleytronics and spintronics in the same device. PMID:25287881

  2. Mapping spin coherence of a single rare-earth ion in a crystal onto a single photon polarization state

    E-print Network

    Roman Kolesov; Kangwei Xia; Rolf Reuter; Rainer Stoehr; Tugrul Inal; Petr Siyushev; Joerg Wrachtrup

    2013-01-22

    We report on optical detection of a single photostable Ce3+ ion in an yttrium aluminium garnet (YAG) crystal and on its magneto-optical properties at room temperature. The quantum state of an electron spin of the emitting level of cerium ion in YAG can be initialized by circularly polarized laser pulse. Furthermore, its quantum state can be read out by observing temporal behaviour of circularly polarized fluorescence of the ion. This implies direct mapping of the spin quantum state of Ce3+ ion onto the polarization state of the emitted photon and represents one-way quantum interface between a single spin and a single photon.

  3. All-optical preparation of coherent dark states of a single rare earth ion spin in a crystal

    E-print Network

    Kangwei Xia; Roman Kolesov; Ya Wang; Petr Siyushev; Rolf Reuter; Thomas Kornher; Nadezhda Kukharchyk; Andreas D. Wieck; Bruno Villa; Sen Yang; Jörg Wrachtrup

    2015-06-22

    All-optical addressing and control of single solid-state based qubits allows for scalable architectures of quantum devices such as quantum networks and quantum simulators. So far, all-optical addressing of qubits was demonstrated only for color centers in diamond and quantum dots. Here, we demonstrate generation of coherent dark state of a single rare earth ion in a solid, namely a cerium ion in yttrium aluminum garnet (YAG). The dark state was formed under the condition of coherent population trapping. Furthermore, high-resolution spectroscopic studies of native and implanted single Ce ions have been performed. They revealed narrow and spectrally stable optical transitions between the spin sublevels of the ground and excited optical states, indicating the feasibility of interfacing single photons with a single electron spin of a cerium ion.

  4. Coherent spin control by electrical manipulation of the magnetic anisotropy.

    PubMed

    George, Richard E; Edwards, James P; Ardavan, Arzhang

    2013-01-11

    High-spin paramagnetic manganese defects in polar piezoelectric zinc oxide exhibit a simple, almost axial anisotropy and phase coherence times of the order of a millisecond at low temperatures. The anisotropy energy is tunable using an externally applied electric field. This can be used to control electrically the phase of spin superpositions and to drive spin transitions with resonant microwave electric fields. PMID:23383938

  5. Polarization Dependence of the Spin-Density-Wave Excitations in Single-Domain Chromium

    SciTech Connect

    Boeni, P. [Labor fuer Neutronenstreuung, Villigen PSI (Switzerland); Sternlieb, B.J.; Shirane, G. [Brookhaven National Lab., Upton, NY (United States); Roessli, B.; Werner, S.A. [Institut Laue Langevin, Grenoble Cedex (France); Lorenzo, J.E. [Laboratoire de Crystallographie, CNRS, Grenoble (France)

    1997-12-31

    A polarised neutron scattering experiment has been performed on a single-Q, single domain sample of Cr in a magnetic field of 4 T in the transverse spin-density-wave phase. It is confirmed that the longitudinal fluctuations are enhanced for energy transfers E {lt} 8 meV similarly as in the longitudinal spin-density-wave phase. The spin wave modes with deltaS parallel and perpendicular to Q are isotropic within the E-range investigated.

  6. All-optical control of a solid-state spin using coherent dark states

    PubMed Central

    Yale, Christopher G.; Buckley, Bob B.; Christle, David J.; Burkard, Guido; Heremans, F. Joseph; Bassett, Lee C.; Awschalom, David D.

    2013-01-01

    The study of individual quantum systems in solids, for use as quantum bits (qubits) and probes of decoherence, requires protocols for their initialization, unitary manipulation, and readout. In many solid-state quantum systems, these operations rely on disparate techniques that can vary widely depending on the particular qubit structure. One such qubit, the nitrogen-vacancy (NV) center spin in diamond, can be initialized and read out through its special spin-selective intersystem crossing, while microwave electron spin resonance techniques provide unitary spin rotations. Instead, we demonstrate an alternative, fully optical approach to these control protocols in an NV center that does not rely on its intersystem crossing. By tuning an NV center to an excited-state spin anticrossing at cryogenic temperatures, we use coherent population trapping and stimulated Raman techniques to realize initialization, readout, and unitary manipulation of a single spin. Each of these techniques can be performed directly along any arbitrarily chosen quantum basis, removing the need for extra control steps to map the spin to and from a preferred basis. Combining these protocols, we perform measurements of the NV center’s spin coherence, a demonstration of this full optical control. Consisting solely of optical pulses, these techniques enable control within a smaller footprint and within photonic networks. Likewise, this unified approach obviates the need for both electron spin resonance manipulation and spin addressability through the intersystem crossing. This method could therefore be applied to a wide range of potential solid-state qubits, including those which currently lack a means to be addressed. PMID:23610403

  7. Controlling spins in adsorbed molecules by a chemical switch

    PubMed Central

    Wäckerlin, Christian; Chylarecka, Dorota; Kleibert, Armin; Müller, Kathrin; Iacovita, Cristian; Nolting, Frithjof; Jung, Thomas A.; Ballav, Nirmalya

    2010-01-01

    The development of chemical systems with switchable molecular spins could lead to the architecture of materials with controllable magnetic or spintronic properties. Here, we present conclusive evidence that the spin of an organometallic molecule coupled to a ferromagnetic substrate can be switched between magnetic off and on states by a chemical stimulus. This is achieved by nitric oxide (NO) functioning as an axial ligand of cobalt(II)tetraphenylporphyrin (CoTPP) ferromagnetically coupled to nickel thin-film (Ni(001)). On NO addition, the coordination sphere of Co2+ is modified and a NO–CoTPP nitrosyl complex is formed, which corresponds to an off state of the Co spin. Thermal dissociation of NO from the nitrosyl complex restores the on state of the Co spin. The NO-induced reversible off–on switching of surface-adsorbed molecular spins observed here is attributed to a spin trans effect. PMID:20975713

  8. Terahertz spin current pulses controlled by magnetic heterostructures.

    PubMed

    Kampfrath, T; Battiato, M; Maldonado, P; Eilers, G; Nötzold, J; Mährlein, S; Zbarsky, V; Freimuth, F; Mokrousov, Y; Blügel, S; Wolf, M; Radu, I; Oppeneer, P M; Münzenberg, M

    2013-04-01

    In spin-based electronics, information is encoded by the spin state of electron bunches. Processing this information requires the controlled transport of spin angular momentum through a solid, preferably at frequencies reaching the so far unexplored terahertz regime. Here, we demonstrate, by experiment and theory, that the temporal shape of femtosecond spin current bursts can be manipulated by using specifically designed magnetic heterostructures. A laser pulse is used to drive spins from a ferromagnetic iron thin film into a non-magnetic cap layer that has either low (ruthenium) or high (gold) electron mobility. The resulting transient spin current is detected by means of an ultrafast, contactless amperemeter based on the inverse spin Hall effect, which converts the spin flow into a terahertz electromagnetic pulse. We find that the ruthenium cap layer yields a considerably longer spin current pulse because electrons are injected into ruthenium d states, which have a much lower mobility than gold sp states. Thus, spin current pulses and the resulting terahertz transients can be shaped by tailoring magnetic heterostructures, which opens the door to engineering high-speed spintronic devices and, potentially, broadband terahertz emitters. PMID:23542903

  9. Fast Room-Temperature Phase Gate on a Single Nuclear Spin in Diamond

    E-print Network

    S. Sangtawesin; T. O. Brundage; J. R. Petta

    2014-07-14

    Nuclear spins support long lived quantum coherence due to weak coupling to the environment, but are difficult to rapidly control using nuclear magnetic resonance (NMR) as a result of the small nuclear magnetic moment. We demonstrate a fast ~ 500 ns nuclear spin phase gate on a 14N nuclear spin qubit intrinsic to a nitrogen-vacancy (NV) center in diamond. The phase gate is enabled by the hyperfine interaction and off-resonance driving of electron spin transitions. Repeated applications of the phase gate bang-bang decouple the nuclear spin from the environment, locking the spin state for up to ~ 140 microseconds.

  10. Single Transverse Spin Asymmetries in Semi-inclusive Deep Inelastic Scattering in a Spin-1 Diquark Model

    E-print Network

    Narinder Kumar; Harleen Dahiya

    2015-04-15

    The observed results for the azimuthal single spin asymmetries (SSAs) of the proton, measured in the semi-inclusive deep inelastic scattering (SIDIS), can be explained by the final-state interaction (FSI) from the gluon exchange between the outgoing quark and the target spectator system. SSAs require a phase difference between two amplitudes coupling the target with opposite spins to the same final state. We have used the model of light front wave functions (LFWFs) consisting of a spin-$\\frac{1}{2}$ system as a composite of a spin-$\\frac{1}{2}$ fermion and a spin-1 vector boson to estimate the SSAs. The implications of such a model have been investigated in detail by considering different coupling constants. The FSIs also produce a complex phase which can be included in the LFWFs to calculate the Sivers and Boer-Mulders distribution functions of the nucleon.

  11. Controlled Spin Transport in Planar Systems Through Topological Exciton

    E-print Network

    Abhinav, Kumar

    2015-01-01

    It is shown that a charge-neutral spin-1 exciton, possibly realizable only in planar systems like graphene and topological insulators, can be effectively used for controlled spin transport in such media. The effect of quantum and thermal fluctuations yield a parametric excitation threshold for its realization. This planar exciton differs from the conventional ones, as it owes its existence to the topological Chern-Simons (CS) term. The parity and time-reversal violating CS term can arise from quantum effects in systems with parity-breaking mass-gap. The spinning exciton naturally couples to magnetic field, leading to the possibility of controlled spin transport. Being neutral, it is immune to a host of effect, which afflicts spin transport through charged fermions.

  12. Photonic transport control by spin-optical disordered metasurface

    E-print Network

    Veksler, Dekel; Ozeri, Dror; Shitrit, Nir; Kleiner, Vladimir; Hasman, Erez

    2014-01-01

    Photonic metasurfaces are ultrathin electromagnetic wave-molding metamaterials providing the missing link for the integration of nanophotonic chips with nanoelectronic circuits. An extra twist in this field originates from spin-optical metasurfaces providing the photon spin (polarization helicity) as an additional degree of freedom in light-matter interactions at the nanoscale. Here we report on a generic concept to control the photonic transport by disordered (random) metasurfaces with a custom-tailored geometric phase. This approach combines the peculiarity of random patterns to support extraordinary information capacity within the intrinsic limit of speckle noise, and the optical spin control in the geometric phase mechanism, simply implemented in two-dimensional structured matter. By manipulating the local orientations of anisotropic optical nanoantennas, we observe spin-dependent near-field and free-space open channels, generating state-of-the-art multiplexing and interconnects. Spin-optical disordered m...

  13. Active control of magnetoresistance of organic spin valves using ferroelectricity

    PubMed Central

    Sun, Dali; Fang, Mei; Xu, Xiaoshan; Jiang, Lu; Guo, Hangwen; Wang, Yanmei; Yang, Wenting; Yin, Lifeng; Snijders, Paul C.; Ward, T. Z.; Gai, Zheng; Zhang, X.-G.; Lee, Ho Nyung; Shen, Jian

    2014-01-01

    Organic spintronic devices have been appealing because of the long spin lifetime of the charge carriers in the organic materials and their low cost, flexibility and chemical diversity. In previous studies, the control of resistance of organic spin valves is generally achieved by the alignment of the magnetization directions of the two ferromagnetic electrodes, generating magnetoresistance. Here we employ a new knob to tune the resistance of organic spin valves by adding a thin ferroelectric interfacial layer between the ferromagnetic electrode and the organic spacer: the magnetoresistance of the spin valve depends strongly on the history of the bias voltage, which is correlated with the polarization of the ferroelectric layer; the magnetoresistance even changes sign when the electric polarization of the ferroelectric layer is reversed. These findings enable active control of resistance using both electric and magnetic fields, opening up possibility for multi-state organic spin valves. PMID:25008155

  14. Controlled Spin Transport in Planar Systems Through Topological Exciton

    E-print Network

    Kumar Abhinav; Prasanta K. Panigrahi

    2015-04-29

    It is shown that a charge-neutral spin-1 exciton, possibly realizable only in planar systems like graphene and topological insulators, can be effectively used for controlled spin transport in such media. The effect of quantum and thermal fluctuations yield a parametric excitation threshold for its realization. This planar exciton differs from the conventional ones, as it owes its existence to the topological Chern-Simons (CS) term. The parity and time-reversal violating CS term can arise from quantum effects in systems with parity-breaking mass-gap. The spinning exciton naturally couples to magnetic field, leading to the possibility of controlled spin transport. Being neutral, it is immune to a host of effect, which afflicts spin transport through charged fermions.

  15. Quantum nondemolition measurement of a single electron spin in a quantum dot

    E-print Network

    Mitsuro Sugita; Susumu Machida; Yoshihisa Yamamoto

    2003-01-15

    We propose a scheme for the quantum nondemolition (QND) measurement of a single electron spin in a single quantum dot (QD). Analytical expressions are obtained for the optical Faraday effect between a quantum dot exciton and microcavity field. The feasibility of the QND measurement of a single electron spin is discussed for a GaAs/AlAs microcavity with an InAs QD.

  16. Nearly Perfect Spin Filter, Spin Valve and Negative Differential Resistance Effects in a Fe4-based Single-molecule Junction

    PubMed Central

    Zu, Fengxia; Liu, Zuli; Yao, Kailun; Gao, Guoying; Fu, Huahua; Zhu, Sicong; Ni, Yun; Peng, Li

    2014-01-01

    The spin-polarized transport in a single-molecule magnet Fe4 sandwiched between two gold electrodes is studied, using nonequilibrium Green's functions in combination with the density-functional theory. We predict that the device possesses spin filter effect (SFE), spin valve effect (SVE), and negative differential resistance (NDR) behavior. Moreover, we also find that the appropriate chemical ligand, coupling the single molecule to leads, is a key factor for manipulating spin-dependent transport. The device containing the methyl ligand behaves as a nearly perfect spin filter with efficiency approaching 100%, and the transport is dominated by transmission through the Fe4 metal center. However, in the case of phenyl ligand, the spin filter effect seems to be reduced, but the spin valve effect is significantly enhanced with a large magnetoresistance ratio, reaching 1800%. This may be attributed to the blocking effect of the phenyl ligands in mediating transport. Our findings suggest that such a multifunctional molecular device, possessing SVE, NDR and high SFE simultaneously, would be an excellent candidate for spintronics of molecular devices. PMID:24787446

  17. Spin-controlled plasmonics via optical Rashba effect

    SciTech Connect

    Shitrit, Nir; Yulevich, Igor; Kleiner, Vladimir; Hasman, Erez, E-mail: mehasman@technion.ac.il [Micro and Nanooptics Laboratory, Faculty of Mechanical Engineering, and Russell Berrie Nanotechnology Institute, Technion—Israel Institute of Technology, Haifa 32000 (Israel)] [Micro and Nanooptics Laboratory, Faculty of Mechanical Engineering, and Russell Berrie Nanotechnology Institute, Technion—Israel Institute of Technology, Haifa 32000 (Israel)

    2013-11-18

    Observation of the optical Rashba effect in plasmonics is reported. Polarization helicity degeneracy removal, associated with the inversion symmetry violation, is attributed to the surface symmetry design via anisotropic nanoantennas with space-variant orientations. By utilizing the Rashba-induced momentum in a nanoscale kagome metastructure, we demonstrated a spin-based surface plasmon multidirectional excitation under a normal-incidence illumination. The spin-controlled plasmonics via spinoptical metasurfaces provides a route for spin-based surface-integrated photonic nanodevices and light-matter interaction control, extending the light manipulation capabilities.

  18. Probing Johnson noise and ballistic transport in normal metals with a single-spin qubit

    NASA Astrophysics Data System (ADS)

    Kolkowitz, S.; Safira, A.; High, A. A.; Devlin, R. C.; Choi, S.; Unterreithmeier, Q. P.; Patterson, D.; Zibrov, A. S.; Manucharyan, V. E.; Park, H.; Lukin, M. D.

    2015-03-01

    Thermally induced electrical currents, known as Johnson noise, cause fluctuating electric and magnetic fields in proximity to a conductor. These fluctuations are intrinsically related to the conductivity of the metal. We use single-spin qubits associated with nitrogen-vacancy centers in diamond to probe Johnson noise in the vicinity of conductive silver films. Measurements of polycrystalline silver films over a range of distances (20 to 200 nanometers) and temperatures (10 to 300 kelvin) are consistent with the classically expected behavior of the magnetic fluctuations. However, we find that Johnson noise is markedly suppressed next to single-crystal films, indicative of a substantial deviation from Ohm’s law at length scales below the electron mean free path. Our results are consistent with a generalized model that accounts for the ballistic motion of electrons in the metal, indicating that under the appropriate conditions, nearby electrodes may be used for controlling nanoscale optoelectronic, atomic, and solid-state quantum systems.

  19. Spinoptical metamaterials: spin-controlled photonics based on symmetry violation

    NASA Astrophysics Data System (ADS)

    Shitrit, Nir; Yulevich, Igor; Maguid, Elhanan; Ozeri, Dror; Veksler, Dekel; Kleiner, Vladimir; Hasman, Erez

    2013-09-01

    Spinoptics provides a route to control light, whereby the photon helicity (spin angular momentum) degeneracy is removed due to a geometric gradient onto a metasurface. The alliance of spinoptics and metamaterials offers the dispersion engineering of a structured matter in a polarization helicity dependent manner. We show that polarization-controlled optical modes of metamaterials arise where the spatial inversion symmetry is violated. The emerged spin-split dispersion of spontaneous emission originates from the spin-orbit interaction of light, generating a selection rule based on symmetry restrictions in a spinoptical metamaterial. The inversion asymmetric metasurface is obtained via anisotropic optical antenna patterns. This type of metamaterial provides a route for spin-controlled nanophotonic applications based on the design of the metasurface symmetry properties.

  20. Single-Transverse Spin Asymmetry in Dijet Correlations at Hadron Colliders

    E-print Network

    C. J. Bomhof; P. J. Mulders; W. Vogelsang; F. Yuan

    2007-01-31

    We present a phenomenological study of the single-transverse spin asymmetry in azimuthal correlations of two jets produced nearly "back-to-back" in pp collisions at RHIC. We properly take into account the initial- and final-state interactions of partons that can generate this asymmetry in QCD hard-scattering. Using distribution functions fitted to the existing single-spin data, we make predictions for various weighted single-spin asymmetries in dijet correlations that are now readily testable at RHIC.

  1. Single-photon spin-orbit entanglement violating a Bell-like inequality

    E-print Network

    Lixiang Chen; Weilong She

    2010-01-07

    Single photons emerging from q-plates (or Pancharatnam-Berry phase optical element) exhibit entanglement in the degrees of freedom of spin and orbital angular momentum. We put forward an experimental scheme for probing the spin-orbit correlations of single photons. It is found that the Clauser-Horne-Shimony-Holt (CHSH) parameter S for the single-photon spin-orbit entangled state could be up to 2.828, evidently violating the Bell-like inequality and thus invalidating the noncontextual hidden variable (NCHV) theories.

  2. Spin-controlled mechanics in nanoelectromechanical systems

    NASA Astrophysics Data System (ADS)

    Radi?, D.

    2015-03-01

    We consider a dc-electronic tunneling transport through a carbon nanotube suspended between normal-metal source and arbitrarily spin-polarized drain lead in the presence of an external magnetic field. We show that magnetomotive coupling between electrical current through the nanotube and its mechanical vibrations may lead to an electromechanical instability and give an onset of self-excited mechanical vibrations depending on spin polarization of the drain lead and frequency of vibrations. The self-excitation mechanism is based on correlation between the occupancy of quantized Zeeman-split electronic states in the nanotube and the direction of velocity of its mechanical motion. It is an effective gating effect by the presence of electron in the spin state which, through the Coulomb blockade, permits tunneling of electron to the drain predominantly only during a particular phase of mechanical vibration thus coherently changing mechanical momentum and leading into instability if mechanical damping is overcome.

  3. Electric Control of Spin Injection into a Ferroelectric Semiconductor

    NASA Astrophysics Data System (ADS)

    Liu, Xiaohui; Burton, J. D.; Zhuravlev, M. Ye.; Tsymbal, Evgeny Y.

    2015-01-01

    Electric-field control of spin-dependent properties has become one of the most attractive phenomena in modern materials research due to the promise of new device functionalities. One of the paradigms in this approach is to electrically toggle the spin polarization of carriers injected into a semiconductor using ferroelectric polarization as a control parameter. Using first-principles density-functional calculations, we explore the effect of ferroelectric polarization of electron-doped BaTiO3 (n -BaTiO3 ) on the spin-polarized transmission across the SrRuO3/n -BaTiO3(001 ) interface. Our study reveals that, in this system, the interface transmission is negatively spin polarized and that ferroelectric polarization reversal leads to a change in the transport spin polarization from -65 % to -98 % . Analytical model calculations demonstrate that this is a general effect for ferromagnetic-metal-ferroelectric-semiconductor systems and, furthermore, that ferroelectric modulation can even reverse the sign of spin polarization. The predicted effect provides a nonvolatile mechanism to electrically control spin injection in semiconductor-based spintronics devices.

  4. Electric control of spin injection into a ferroelectric semiconductor.

    PubMed

    Liu, Xiaohui; Burton, J D; Zhuravlev, M Ye; Tsymbal, Evgeny Y

    2015-01-30

    Electric-field control of spin-dependent properties has become one of the most attractive phenomena in modern materials research due to the promise of new device functionalities. One of the paradigms in this approach is to electrically toggle the spin polarization of carriers injected into a semiconductor using ferroelectric polarization as a control parameter. Using first-principles density-functional calculations, we explore the effect of ferroelectric polarization of electron-doped BaTiO3 (n-BaTiO3) on the spin-polarized transmission across the SrRuO3/n-BaTiO3(001) interface. Our study reveals that, in this system, the interface transmission is negatively spin polarized and that ferroelectric polarization reversal leads to a change in the transport spin polarization from -65% to -98%. Analytical model calculations demonstrate that this is a general effect for ferromagnetic-metal-ferroelectric-semiconductor systems and, furthermore, that ferroelectric modulation can even reverse the sign of spin polarization. The predicted effect provides a nonvolatile mechanism to electrically control spin injection in semiconductor-based spintronics devices. PMID:25679900

  5. Control of exciton spin statistics through spin polarization in organic optoelectronic devices

    PubMed Central

    Wang, Jianpu; Chepelianskii, Alexei; Gao, Feng; Greenham, Neil C.

    2012-01-01

    Spintronics based on organic semiconductor materials is attractive because of its rich fundamental physics and potential for device applications. Manipulating spins is obviously important for spintronics, and is usually achieved by using magnetic electrodes. Here we show a new approach where spin populations can be controlled primarily by energetics rather than kinetics. We find that exciton spin statistics can be substantially controlled by spin-polarizing carriers after injection using high magnetic fields and low temperatures, where the Zeeman energy is comparable with the thermal energy. By using this method, we demonstrate that singlet exciton formation can be suppressed by up to 53% in organic light-emitting diodes, and the dark conductance of organic photovoltaic devices can be increased by up to 45% due to enhanced formation of triplet charge-transfer states, leading to less recombination to the ground state. PMID:23149736

  6. Control of propagating spin waves via spin transfer torque in a metallic bilayer waveguide

    NASA Astrophysics Data System (ADS)

    An, Kyongmo; Birt, Daniel R.; Pai, Chi-Feng; Olsson, Kevin; Ralph, Daniel C.; Buhrman, Robert A.; Li, Xiaoqin

    2014-04-01

    We investigate the effect of a direct current on propagating spin waves in a CoFeB/Ta bilayer structure. Using the micro-Brillouin light scattering technique, we observe that the spin-wave damping and amplitude may be attenuated or amplified depending on the direction of the current and the applied magnetic field. Our work suggests an effective approach for electrically controlling the propagation of spin waves in a magnetic waveguide and may be useful in a number of applications such as phase-locked nano-oscillators and hybrid information-processing devices.

  7. Controlling chemical reactions of a single particle

    E-print Network

    Ratschbacher, Lothar; Sias, Carlo; Köhl, Michael

    2012-01-01

    The control of chemical reactions is a recurring theme in physics and chemistry. Traditionally, chemical reactions have been investigated by tuning thermodynamic parameters, such as temperature or pressure. More recently, physical methods such as laser or magnetic field control have emerged to provide completely new experimental possibilities, in particular in the realm of cold collisions. The control of reaction pathways is also a critical component to implement molecular quantum information processing. For these undertakings, single particles provide a clean and well-controlled experimental system. Here, we report on the experimental tuning of the exchange reaction rates of a single trapped ion with ultracold neutral atoms by exerting control over both their quantum states. We observe the influence of the hyperfine interaction on chemical reaction rates and branching ratios, and monitor the kinematics of the reaction products. These investigations advance chemistry with single trapped particles towards achi...

  8. Single-Quantum Coherence Filter for Strongly Coupled Spin Systems for Localized 1H NMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Trabesinger, Andreas H.; Mueller, D. Christoph; Boesiger, Peter

    2000-08-01

    A pulse sequence for localized in vivo1H NMR spectroscopy is presented, which selectively filters single-quantum coherence built up by strongly coupled spin systems. Uncoupled and weakly coupled spin systems do not contribute to the signal output. Analytical calculations using a product operator description of the strongly coupled AB spin system as well as in vitro tests demonstrate that the proposed filter produces a signal output for a strongly coupled AB spin system, whereas the resonances of a weakly coupled AX spin system and of uncoupled spins are widely suppressed. As a potential application, the detection of the strongly coupled AA?BB? spin system of taurine at 1.5 T is discussed.

  9. Nanoscale magnetic imaging of a single electron spin under ambient conditions

    NASA Astrophysics Data System (ADS)

    Grinolds, M. S.; Hong, S.; Maletinsky, P.; Luan, L.; Lukin, M. D.; Walsworth, R. L.; Yacoby, A.

    2013-04-01

    The detection of ensembles of spins under ambient conditions has revolutionized the biological, chemical and physical sciences through magnetic resonance imaging and nuclear magnetic resonance. Pushing sensing capabilities to the individual-spin level would enable unprecedented applications such as single-molecule structural imaging; however, the weak magnetic fields from single spins are undetectable by conventional far-field resonance techniques. In recent years, there has been a considerable effort to develop nanoscale scanning magnetometers, which are able to measure fewer spins by bringing the sensor in close proximity to its target. The most sensitive of these magnetometers generally require low temperatures for operation, but the ability to measure under ambient conditions (standard temperature and pressure) is critical for many imaging applications, particularly in biological systems. Here we demonstrate detection and nanoscale imaging of the magnetic field from an initialized single electron spin under ambient conditions using a scanning nitrogen-vacancy magnetometer. Real-space, quantitative magnetic-field images are obtained by deterministically scanning our nitrogen-vacancy magnetometer 50nm above a target electron spin, while measuring the local magnetic field using dynamically decoupled magnetometry protocols. We discuss how this single-spin detection enables the study of a variety of room-temperature phenomena in condensed-matter physics with an unprecedented combination of spatial resolution and spin sensitivity.

  10. Single Spin Asymmetries of Identified Hadrons in Polarized p+p at p

    E-print Network

    Single Spin Asymmetries of Identified Hadrons in Polarized p+p at p s = 62.4 and 200 GeV J.H. Lee hadrons, p #6; , K #6; , p, and â?¢ p, from transversely polarized proton collisions at p s = 200 and 62 into the fundamental mechanisms of transverse spin asymmetries and Quantum Chromodynamical description of hadronic

  11. Temperature induced Spin Switching in SmFeO3 Single Crystal

    PubMed Central

    Cao, Shixun; Zhao, Huazhi; Kang, Baojuan; Zhang, Jincang; Ren, Wei

    2014-01-01

    The prospect of controlling the magnetization (M) of a material is of great importance from the viewpoints of fundamental physics and future applications of emerging spintronics. A class of rare-earth orthoferrites RFeO3 (R is rare-earth element) materials exhibit striking physical properties of spin switching and magnetization reversal induced by temperature and/or applied magnetic field. Furthermore, due to the novel magnetic, magneto-optic and multiferroic properties etc., RFeO3 materials are attracting more and more interests in recent years. We have prepared and investigated a prototype of RFeO3 materials, namely SmFeO3 single-crystal. And we report magnetic measurements upon both field cooling (FC) and zero-field cooling (ZFC) of the sample, as a function of temperature and applied magnetic field. The central findings of this study include that the magnetization of single-crystal SmFeO3 can be switched by temperature, and tuning the magnitude of applied magnetic field allows us to realize such spin switching even at room temperature. PMID:25091202

  12. Temperature induced spin switching in SmFeO3 single crystal.

    PubMed

    Cao, Shixun; Zhao, Huazhi; Kang, Baojuan; Zhang, Jincang; Ren, Wei

    2014-01-01

    The prospect of controlling the magnetization (M) of a material is of great importance from the viewpoints of fundamental physics and future applications of emerging spintronics. A class of rare-earth orthoferrites RFeO3 (R is rare-earth element) materials exhibit striking physical properties of spin switching and magnetization reversal induced by temperature and/or applied magnetic field. Furthermore, due to the novel magnetic, magneto-optic and multiferroic properties etc., RFeO3 materials are attracting more and more interests in recent years. We have prepared and investigated a prototype of RFeO3 materials, namely SmFeO3 single-crystal. And we report magnetic measurements upon both field cooling (FC) and zero-field cooling (ZFC) of the sample, as a function of temperature and applied magnetic field. The central findings of this study include that the magnetization of single-crystal SmFeO3 can be switched by temperature, and tuning the magnitude of applied magnetic field allows us to realize such spin switching even at room temperature. PMID:25091202

  13. Controlling the Gilbert damping using spin pumping and magnetic impurities

    NASA Astrophysics Data System (ADS)

    Verhagen, Tim; Tinkey, Holly; van Ruitenbeek, Jan; Aarts, Jan

    2013-03-01

    The ability to control the magnetic damping parameter of thin magnetic films is an important issue when designing for example giant magnetoresistance (GMR) devices. A well-known way to influence the damping of the ferromagnetic (F) layer is by using the spin pumping effect in which a spin current is emitted into an adjacent normal (N) layer by bringing the F-layer into ferromagnetic resonance (FMR). As N layer, we used the well studied strongly spin sinking material Pt and the bad spin sink Cu, but also a Cu layer with Co impurities. We find that by adding a small amount of Co impurities, the Cu layer becomes as effective in damping as a Pt layer. In the latter case, the damping is caused by the strong spin orbit coupling. Using magnetic impurities, we rather make use of the inelastic spin scattering. This opens up new ways to control the damping of a ferromagnetic thin layer, for example in current-in-plane (CIP) GMR sensors, where the extra damping can suppress the spin transfer torque which becomes dominant with the further decrease of the size of the sensor.

  14. Coherent control of atomic spin currents in a double well

    E-print Network

    H. T. Ng; Shih-I Chu

    2012-02-23

    We propose an experimental feasible method for controlling the atomic currents of a two-component Bose-Einstein condensate in a double well by applying an external field to the atoms in one of the potential wells. We study the ground-state properties of the system and show that the directions of spin currents and net-particle tunneling can be manipulated by adiabatically varying the coupling strength between the atoms and the field. This system can be used for studying spin and tunneling phenomena across a wide range of interaction parameters. In addition, spin-squeezed states can be generated. It is useful for quantum information processing and quantum metrology.

  15. Coherent control of atomic spin currents in a double well

    NASA Astrophysics Data System (ADS)

    Ng, H. T.; Chu, Shih-I.

    2012-02-01

    We propose a method for controlling the atomic currents of a two-component Bose-Einstein condensate in a double well by applying an external field to the atoms in one of the potential wells. We study the ground-state properties of the system and show that the directions of spin currents and net-particle tunneling can be manipulated by adiabatically varying the coupling strength between the atoms and the field. This system can be used to study spin and tunneling phenomena across a wide range of interaction parameters. In addition, spin-squeezed states can be generated. It is useful for quantum information processing and quantum metrology.

  16. Optimal and suboptimal control technique for aircraft spin recovery

    NASA Technical Reports Server (NTRS)

    Young, J. W.

    1974-01-01

    An analytic investigation has been made of procedures for effecting recovery from equilibrium spin conditions for three assumed aircraft configurations. Three approaches which utilize conventional aerodynamic controls are investigated. Included are a constant control recovery mode, optimal recoveries, and a suboptimal control logic patterned after optimal recovery results. The optimal and suboptimal techniques are shown to yield a significant improvement in recovery performance over that attained by using a constant control recovery procedure.

  17. Floquet control of quantum dissipation in spin chains

    NASA Astrophysics Data System (ADS)

    Chen, Chong; An, Jun-Hong; Luo, Hong-Gang; Sun, C. P.; Oh, C. H.

    2015-05-01

    Controlling the decoherence induced by the interaction of quantum system with its environment is a fundamental challenge in quantum technology. Utilizing Floquet theory, we explore the constructive role of temporal periodic driving in suppressing decoherence of a spin-1/2 particle coupled to a spin bath. It is revealed that, accompanying the formation of a Floquet bound state in the quasienergy spectrum of the whole system including the system and its environment, the dissipation of the spin system can be inhibited and the system tends to coherently synchronize with the driving. It can be seen as an analog to the decoherence suppression induced by the structured environment in spatially periodic photonic crystal setting. Comparing with other decoherence control schemes, our protocol is robust against the fluctuation of control parameters and easy to realize in practice. It suggests a promising perspective of periodic driving in decoherence control.

  18. Noise-resistant optimal spin squeezing via quantum control

    E-print Network

    T. Pichler; T. Caneva; S. Montangero; M. D. Lukin; T. Calarco

    2015-06-08

    Entangled atomic states, such as spin squeezed states, represent a promising resource for a new generation of quantum sensors and atomic clocks. We demonstrate that optimal control techniques can be used to substantially enhance the degree of spin squeezing in strongly interacting many-body systems, even in the presence of noise and imperfections. Specifically, we present a protocol that is robust to noise which outperforms conventional methods. Potential experimental implementations are discussed.

  19. Galileo dual-spin attitude and articulation control system

    NASA Technical Reports Server (NTRS)

    Ward, R. S.

    1978-01-01

    Galileo, the first outer planet explorer to be configured as a dual spinner, will conduct intensive investigation of Jupiter's atmosphere, satellites, and magnetosphere. The exacting mission, coupled with the inherently complex spin and flexible body dynamics of the vehicle, demands careful design of the Galileo Attitude and Articulation Control System (AACS). A brief overview of the Galileo mission and spacecraft is presented, followed by a detailed discussion on the mechanization of the AACS and the many factors that influence its design. Included are discussions on attitude determination and control, high-gain antenna pointing, science scan platform pointing, nutation damping, wobble compensation, spin and despin control, and propellant migration and boom flexibility effects.

  20. Bell's inequality for a single spin 1/2 particle and quantum contextuality

    E-print Network

    Sayandeb Basu; Somshubhro Bandyopadhyay; Guruprasad Kar; Dipankar Home

    2001-03-18

    We argue that for a \\emph{single particle} Bell's inequality is a consequence of noncontextuality and is \\emph{incompatible} with statistical predictions of quantum mechanics. Thus noncontextual models can be empirically falsified, \\emph{independent} of locality condition. For this an appropriate entanglement between \\emph{disjoint} Hilbert spaces pertaining to translational and spin degrees of freedom of a single spin-1/2 particle is invoked

  1. Single Transverse Spin Asymmetry for Semi-Inclusive Deep Inelastic Scattering

    E-print Network

    Hisato Eguchi; Yuji Koike; Kazuhiro Tanaka

    2006-12-08

    Establishing the twist-3 formalsim for the single transverse spin asymmetry, we present a complete single-spin-dependent cross section for SIDIS, $ep^\\uparrow\\to e\\pi X$, associated with the twist-3 distribution for the transversely polarized nucleon. We emphasize that the consistency condition from the Ward identities for color gauge invariance is crucial to prove factorization property of the cross section.

  2. Coherent control and detection of spin qubits in semiconductor with magnetic field engineering

    NASA Astrophysics Data System (ADS)

    Tokura, Yasuhiro

    2012-02-01

    Electrical control and detection of the spin qubits in semiconductor quantum dots (QDs) are among the major rapidly progressing fields for possible implementation of scalable quantum information processing. Coherent control of one-[1-3] and two-[4,5] spin qubits by electrical means had been demonstrated with various approaches. We have used an engineered magnetic field structure realized with proximal micro-magnets to transduce the spin and charge degrees of freedom and to selectively address one of the two spins [3]. We have demonstrated an all-electrical two-qubit gate consisting of single-spin rotations and interdot spin exchange in double QDs. A partially entangled output state is obtained by the application of the two-qubit gate to an initial, uncorrelated state. Our calculations taking into account of the nuclear spin fluctuation show the degree of entanglement. Non-uniform magnetic field also enables spin selective photon-assisted tunneling in double QDs, which then constitutes non-demolition spin read-out system in combination with a near-by charge detector [6]. [4pt] In collaboration with R. Brunner, Inst. of Phys., Montanuniversitaet Leoben, 8700, Austria, M. Pioro-Ladrière, D'ep. de Phys., Universit'e de Sherbrooke, Sherbrooke, Qu'ebec, J1K-2R1, Canada, T. Kubo, Y. -S. Shin, T. Obata, and S. Tarucha, ICORP-JST and Dep. of Appl. Phys., Univ. of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.[4pt] [1] F. H. Koppens, et al., Nature 442, 766 (2006).[0pt] [2] K. C. Nowack, et al., Science 318, 1430 (2007).[0pt] [3] M. Pioro-Ladrière, et al., Nature Physics 4, 776 (2008).[0pt] [4] J. R. Petta, et al., Science 309, 2180 (2005).[0pt] [5] R. Brunner, et al., Phys. Rev. Lett. 107, 146801 (2011).[0pt] [6] Y. -S. Shin, et al., Phys. Rev. Lett. 104, 046802 (2010).

  3. Dual Control of Giant Field-like Spin Torque in Spin Filter Tunnel Junctions

    PubMed Central

    Tang, Y. -H.; Chu, F. -C.; Kioussis, Nicholas

    2015-01-01

    We predict a giant field-like spin torque, , in spin-filter (SF) barrier tunnel junctions in sharp contrast to existing junctions based on nonmagnetic passive barriers. We demonstrate that has linear bias behavior, is independent of the SF thickness, and has odd parity with respect to the SF’s exchange splitting. Thus, it can be selectively controlled via external bias or external magnetic field which gives rise to sign reversal of via magnetic field switching. The underlying mechanism is the interlayer exchange coupling between the noncollinear magnetizations of the SF and free ferromagnetic electrode via the nonmagnetic insulating (I) spacer giving rise to giant spin-dependent reflection at the SF/I interface. These findings suggest that the proposed field-like-spin-torque MRAM may provide promising dual functionalities for both ‘reading’ and ‘writing’ processes which require lower critical current densities and faster writing and reading speeds. PMID:26095146

  4. Linear spin wave theory for single-Q incommensurate magnetic structures.

    PubMed

    Toth, S; Lake, B

    2015-04-29

    Linear spin wave theory provides the leading term in the calculation of the excitation spectra of long-range ordered magnetic systems as a function of 1/?S. This term is acquired using the Holstein-Primakoff approximation of the spin operator and valid for small ?S fluctuations of the ordered moment. We propose an algorithm that allows magnetic ground states with general moment directions and single-Q incommensurate ordering wave vector using a local coordinate transformation for every spin and a rotating coordinate transformation for the incommensurability. Finally we show, how our model can determine the spin wave spectrum of the magnetic C-site langasites with incommensurate order. PMID:25817594

  5. Coherent Control of Spin Precession Motion with Impulsive Magnetic Fields of Half-Cycle Terahertz Radiation

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Keita; Nakajima, Makoto; Suemoto, Tohru

    2010-12-01

    Coherent control of the precession motion of magnetizations in a single crystal YFeO3 with double half-cycle pulse terahertz waves was demonstrated. Quasiferromagnetic (0.299 THz) and quasiantiferromagnetic (0.527 THz) precession modes were selectively excited by choosing an appropriate interval of two pulses and were observed as free induction decay (FID) signals from the spin system. By observing the circularly polarized FID signals due to ferromagnetic resonance, we also succeeded in confirming directly the energy storage in the spin system and recovery from that to the electromagnetic radiation.

  6. Energy levels and decoherence properties of single electron and nuclear spins in a defect center in diamond

    E-print Network

    I. Popa; T. Gaebel; M. Domhan; C. Wittmann; F. Jelezko; J. Wrachtrup

    2004-09-12

    The coherent behavior of the single electron and single nuclear spins of a defect center in diamond and a 13C nucleus in its vicinity, respectively, are investigated. The energy levels associated with the hyperfine coupling of the electron spin of the defect center to the 13C nuclear spin are analyzed. Methods of magnetic resonance together with optical readout of single defect centers have been applied in order to observe the coherent dynamics of the electron and nuclear spins. Long coherence times, in the order of microseconds for electron spins and tens of microseconds for nuclear spins, recommend the studied system as a good experimental approach for implementing a 2-qubit gate.

  7. All spin-1 topological phases in a single spin-2 chain

    NASA Astrophysics Data System (ADS)

    Kshetrimayum, Augustine; Tu, Hong-Hao; Orús, Román

    2015-05-01

    Here we study the emergence of different symmetry-protected topological (SPT) phases in a spin-2 quantum chain. We consider a Heisenberg-like model with bilinear, biquadratic, bicubic, and biquartic nearest-neighbor interactions, as well as uniaxial anisotropy. We show that this model contains four different effective spin-1 SPT phases, corresponding to different representations of the (Z2×Z2)+T symmetry group, where Z2 is some ? rotation in the spin internal space and T is time reversal. One of these phases is equivalent to the usual spin-1 Haldane phase, while the other three are different but also typical of spin-1 systems. The model also exhibits an S O (5 ) -Haldane phase. Moreover, we also find that the transitions between the different effective spin-1 SPT phases are continuous and can be described by a c =2 conformal field theory. At such transitions, indirect evidence suggests a possible effective field theory of four massless Majorana fermions. The results are obtained by approximating the ground state of the system in the thermodynamic limit using matrix product states via the infinite time-evolving block decimation method, as well as by effective field theory considerations. Our findings show that different large effective spin-1 SPT phases separated by continuous quantum phase transitions can be stabilized in a simple quantum spin chain.

  8. Fast Room-Temperature Phase Gate on a Single Nuclear Spin in Diamond

    NASA Astrophysics Data System (ADS)

    Sangtawesin, S.; Brundage, T. O.; Petta, J. R.

    2015-03-01

    Nuclear spins support long lived quantum coherence due to weak coupling to the environment, but are difficult to rapidly control using nuclear magnetic resonance as a result of the small nuclear magnetic moment. We demonstrate a fast ~ 500 ns nuclear spin phase gate on a 14N nuclear spin qubit intrinsic to a nitrogen-vacancy center in high purity diamond. This phase gate is achieved by utilizing electron-nuclear hyperfine interaction. By driving off-resonant Rabi oscillations on the electronic spin, we can generate an arbitrary phase gate on the nuclear spin. We also demonstrate that repeated applications of ?-phase gates can bang-bang decouple the nuclear spin from the environment, locking the spin state for up to 140 ?s. Research was supported by the Sloan and Packard Foundations, the National Science Foundation through Awards DMR-0819860 and DMR-0846341, and the Army Research Office through PECASE Award W911NF-08-1-0189.

  9. Quantum registers based on single NV + n 13C centers in diamond: I. The spin Hamiltonian method

    Microsoft Academic Search

    A. P. Nizovtsev; S. Ya. Kilin; V. A. Pushkarchuk; A. L. Pushkarchuk; S. A. Kuten

    2010-01-01

    Details of the application of the spin Hamiltonian method for studying spin characteristics of a quantum register that includes an electron spin S = 1 of a single NV center in the ground electronic state and nuclear spins I = 1\\/2 of several isotopic atoms 13C located at different lattice sites near the vacancy of the NV center. Two methods

  10. Controlling chemical reactions of a single particle

    E-print Network

    Lothar Ratschbacher; Christoph Zipkes; Carlo Sias; Michael Köhl

    2012-09-26

    The control of chemical reactions is a recurring theme in physics and chemistry. Traditionally, chemical reactions have been investigated by tuning thermodynamic parameters, such as temperature or pressure. More recently, physical methods such as laser or magnetic field control have emerged to provide completely new experimental possibilities, in particular in the realm of cold collisions. The control of reaction pathways is also a critical component to implement molecular quantum information processing. For these undertakings, single particles provide a clean and well-controlled experimental system. Here, we report on the experimental tuning of the exchange reaction rates of a single trapped ion with ultracold neutral atoms by exerting control over both their quantum states. We observe the influence of the hyperfine interaction on chemical reaction rates and branching ratios, and monitor the kinematics of the reaction products. These investigations advance chemistry with single trapped particles towards achieving quantum-limited control of chemical reactions and indicate limits for buffer gas cooling of single ion clocks.

  11. Single spin channels in Fe-doped CoTiSb semiconductor

    NASA Astrophysics Data System (ADS)

    Wang, L. Y.; Dai, X. F.; Wang, X. T.; Li, P. P.; Xia, Q. L.; Zhang, Y.; Cui, Y. T.; Liu, G. D.

    2015-07-01

    The Fe-based single atomic chains are designed in the semiconductive CoTiSb matrix by continuously substituting Fe for Ti, Ti-Sb or Co in [0 0 1] crystallographic direction. The electronic structures and magnetic properties of CoTiSb supercells with the Fe-based single atomic chains have been investigated using the first-principles calculations. We predict that the single atomic chains of Fe-Sb (achieved by substituting Fe for Ti) and Fe-vacancy (achieved by substituting Fe for Co) show a 100% spin polarization and form a very small single spin channel. The single atomic chains of Fe-Fe (achieved by substituting Fe for Ti and Sb) show a spin-gapless characteristic.

  12. Electric-dipole-induced spin resonance in a lateral double quantum dot incorporating two single-domain nanomagnets

    NASA Astrophysics Data System (ADS)

    Forster, F.; Mühlbacher, M.; Schuh, D.; Wegscheider, W.; Ludwig, S.

    2015-05-01

    On-chip magnets can be used to implement relatively large local magnetic field gradients in nanoelectronic circuits. Such field gradients provide possibilities for all-electrical control of electron spin qubits where important coupling constants depend crucially on the detailed field distribution. We present a double quantum dot (QD) hybrid device laterally defined in a GaAs/AlGaAs heterostructure which incorporates two single-domain nanomagnets. They have appreciably different coercive fields which allows us to realize four distinct configurations of the local inhomogeneous field distribution. We perform dc transport spectroscopy in the Pauli-spin blockade regime as well as electric-dipole-induced spin resonance (EDSR) measurements to explore our hybrid nanodevice. Characterizing the two nanomagnets we find excellent agreement with numerical simulations. By comparing the EDSR measurements with a second double QD incorporating just one nanomagnet we reveal an important advantage of having one magnet per QD: It facilitates strong field gradients in each QD and allows us to control the electron spins individually for instance in an EDSR experiment. With just one single-domain nanomagnet and common QD geometries EDSR can likely be performed only in one QD.

  13. Quantum-state tomography of a single nuclear spin qubit of an optically manipulated ytterbium atom

    SciTech Connect

    Noguchi, Atsushi; Kozuma, Mikio [Department of Physics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); ERATO Macroscopic Quantum Control Project, JST, 2-11-16 Yayoi, Bunkyo-Ku, Tokyo 113-8656 (Japan); Eto, Yujiro [ERATO Macroscopic Quantum Control Project, JST, 2-11-16 Yayoi, Bunkyo-Ku, Tokyo 113-8656 (Japan); Ueda, Masahito [ERATO Macroscopic Quantum Control Project, JST, 2-11-16 Yayoi, Bunkyo-Ku, Tokyo 113-8656 (Japan); Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2011-09-15

    A single Yb atom is loaded into a high-finesse optical cavity with a moving lattice, and its nuclear spin state is manipulated using a nuclear magnetic resonance technique. A highly reliable quantum state control with fidelity and purity greater than 0.98 and 0.96, respectively, is confirmed by the full quantum state tomography; a projective measurement with high speed (500 {mu}s) and high efficiency (0.98) is accomplished using the cavity QED technique. Because a hyperfine coupling is induced only when the projective measurement is operational, the long coherence times (T{sub 1}=0.49 s and T{sub 2}=0.10 s) are maintained.

  14. QUALITY CONTROL IN COTTON SPINNING AND WEAVING. SOME PRACTICAL RESULTS

    Microsoft Academic Search

    F. C. TOY; Alberto Barella; L. Viertel

    1957-01-01

    In this communication the results obtained during the introduction of statistical quality control techniques into six mills with more than 100,000 cotton spinning spindles, and 1,500 looms are described.A brief description of the control methods employed, and the particular manufacturing processes used in each mill are given. The improvements obtained by the application of quality control are studied, in particular,

  15. Controlling Spin Dynamics of Magnetic Spin Chains at the Atomic Scale

    NASA Astrophysics Data System (ADS)

    Yan, Shichao; Choi, Deung-Jang; Burgess, Jacob; Rolf-Pissarczyk, Steffen; Loth, Sebastian

    2014-03-01

    By combining radio-frequency circuitry with sub-Kelvin Scanning Tunneling Microscopy (STM), fast electric pump-probe pulses of nanosecond duration can be introduced into the tunneling junction with high fidelity. We apply this technique to study dynamics of Fe trimers which can be assembled with the tip of the STM by placing Fe atoms in a regular pattern on copper nitride surface on Cu(100). The spin relaxation time of Fe trimers is found to be extremely sensitive to variations in their environment. This sensitivity can be used to sense the presence of another spin. By attaching a transition metal atom to the STM tip and approaching it to the nanostructure on the surface we deduce the coupling strength between the magnetic atoms. Furthermore, the magnetic state of long-lived spin chains can be sensed even at several nanometers distance by minute changes of the Fe trimer's spin relaxation time. This work paves the way to study and control spin dynamics of nanostructures with precisely tunable spin environments.

  16. Local Spin Anisotropy Effects upon the Magnetization of Dimer Single Molecule Magnets

    NASA Astrophysics Data System (ADS)

    Klemm, Richard A.; Efremov, Dmitri V.

    2006-09-01

    We present an exactly soluble model of equal spin s1 dimer single molecule magnets. The dimer spins interact via the Heisenberg, Zeeman, and the most general quadratic local and global anisotropic exchange interactions. We derive the Hamiltonian matrix for the general case with each type of anisotropy. For antiferromagnetic couplings and s1 > 1/2, the low temperature T magnetization exhibits a strong influence of single-ion anisotropy. Our results suggest a substantial presence of axial single-ion anisotropy in the s1 = 5/2 Fe2 dimer, [Fe(salen)Cl]2.

  17. Exact solutions for time-optimal control of spin by NMR

    NASA Astrophysics Data System (ADS)

    Shauro, Vitaly

    2015-07-01

    We consider the problem of time-optimal control of quadrupole nucleus with the spin by NMR. In contrast to the conventional methods based on selective pulses, the control is implemented using nonselective pulses separated by free-evolution intervals. Using the Cartan decomposition, the system of equations is obtained for finding parameters of a control field. Partial time-optimal solutions for the important single-qutrit gates (selective rotations and quantum Fourier transform) are found. The strong dependence of minimum gate implementation times on global phase of the gate is observed. The analytical values of minimum times are consistent with the numerical data.

  18. Exact solutions for time-optimal control of spin I=1 by NMR

    E-print Network

    V. P. Shauro

    2015-06-04

    We consider the problem of time-optimal control of quadrupole nucleus with the spin I=1 by NMR. In contrast to the conventional methods based on selective pulses, the control is implemented using nonselective pulses separated by free evolution intervals. Using the Cartan decomposition, the system of equations is obtained for finding parameters of a control field. Partial time-optimal solutions for the important single-qutrit gates (selective rotations and quantum Fourier transform) are found. The strong dependence of minimum gate implementation times on global phase of the gate is observed. The analytical values of minimum times are consistent with the numerical data.

  19. Exact solutions for time-optimal control of spin I=1 by NMR

    NASA Astrophysics Data System (ADS)

    Shauro, Vitaly

    2015-04-01

    We consider the problem of time-optimal control of quadrupole nucleus with the spin I=1 by NMR. In contrast to the conventional methods based on selective pulses, the control is implemented using nonselective pulses separated by free-evolution intervals. Using the Cartan decomposition, the system of equations is obtained for finding parameters of a control field. Partial time-optimal solutions for the important single-qutrit gates (selective rotations and quantum Fourier transform) are found. The strong dependence of minimum gate implementation times on global phase of the gate is observed. The analytical values of minimum times are consistent with the numerical data.

  20. Final-State Interactions and Single-Spin Asymmetries in Semi-Inclusive Deep Inelastic Scattering

    SciTech Connect

    Brodsky, Stanley J.

    2002-01-31

    Recent measurements from the HERMES and SMC collaborations show a remarkably large azimuthal single-spin asymmetries AUL and AUT of the proton in semi-inclusive pion leptoproduction {gamma}*(q)p {yields} {pi}X. We show that final-state interactions from gluon exchange between the outgoing quark and the target spectator system lead to single-spin asymmetries in deep inelastic lepton-proton scattering at leading twist in perturbative QCD; i.e., the rescattering corrections are not power-law suppressed at large photon virtuality Q{sup 2} at fixed x{sub bj}. The existence of such single-spin asymmetries requires a phase difference between two amplitudes coupling the proton target with J{sub P}{sup z} = {+-} 1/2 to the same final-state, the same amplitudes which are necessary to produce a nonzero proton anomalous magnetic moment. We show that the exchange of gauge particles between the outgoing quark and the proton spectators produces a Coulomb-like complex phase which depends on the angular momentum L{sup z} of the proton's constituents and is thus distinct for different proton spin amplitudes. The single-spin asymmetry which arises from such final-state interactions does not factorize into a product of distribution function and fragmentation function, and it is not related to the transversity distribution {delta}q(x, Q) which correlates transversely polarized quarks with the spin of the transversely polarized target nucleon.

  1. Final-State Interactions and Single-Spin Asymmetries in Semi-inclusive Deep Inelastic Scattering

    SciTech Connect

    Brodsky, Stanley J.; /SLAC; Hwang, Dae Sung; /SLAC /Sejong U.; Schmidt, Ivan; /Santa Maria U., Valparaiso

    2007-11-14

    Recent measurements from the HERMES and SMC collaborations show a remarkably large azimuthal single-spin asymmetries A{sub UL} and A{sub UT} of the proton in semi-inclusive pion leptoproduction {gamma}*(q)p {yields} {pi}X. We show that final-state interactions from gluon exchange between the outgoing quark and the target spectator system leads to single-spin asymmetries in deep inelastic lepton-proton scattering at leading twist in perturbative QCD; i.e., the rescattering corrections are not power-law suppressed at large photon virtuality q{sup 2} at fixed x{sub bj}. The existence of such single-spin asymmetries requires a phase difference between two amplitudes coupling the proton target with J{sup z}{sub p} = {+-}1/2 to the same final-state, the same amplitudes which are necessary to produce a nonzero proton anomalous magnetic moment. We show that the exchange of gauge particles between the outgoing quark and the proton spectators produces a Coulomb-like complex phase which depends on the angular momentum L{sup z} of the proton's constituents and thus is distinct for different proton spin amplitudes. The single-spin asymmetry which arises from such final-state interactions does not factorize into a product of structure function and fragmentation function, and it is not related to the transversity distribution {delta}q(x;Q) which correlates transversely polarized quarks with the spin of the transversely polarized target nucleon.

  2. Enhanced Spin Squeezing Through Quantum Control of Qudits

    NASA Astrophysics Data System (ADS)

    Norris, Leigh; Trail, Collin; Jessen, Poul; Deutsch, Ivan

    2012-06-01

    Spin squeezed states have applications in metrology and quantum information processing. Most spin squeezing research to date has focused on ensembles of qubit spins. We explore squeezed state production in an ensemble of spin f>1/2 alkali atoms (qudits). Collective interactions are achieved through coherent quantum feedback of a laser probe, interacting with the ensemble through Faraday interaction. This process is enhanced with control of the atomic qudits, both before and after the collective interaction. Initial preparation increases the collective squeezing parameter through enhancement of resolvable quantum fluctuations, but comes at the price of increased decoherence. We find an optimal state preparation, achieving an increased squeezing parameter while remaining robust to decoherence. After the collective interaction, qudit control maps generated entanglement to different pseudo-spin subspaces where it is metrologically useful, e.g., the clock transition or the stretched state for magnetometry. These considerations highlight the unique capabilities of our platform: we can transfer correlations between subspaces to explore a wider variety of nonclassical states, with ultimate application in sensors or quantum information processors.

  3. Enhanced Spin Squeezing Through Quantum Control of Qudits

    NASA Astrophysics Data System (ADS)

    Norris, Leigh; Trail, Collin; Deutsch, Ivan; Jessen, Poul

    2012-10-01

    Spin squeezed states have applications in metrology and quantum information processing. Most spin squeezing research to date has focused on ensembles of qubit spins. We explore squeezed state production in an ensemble of spin f>1/2 alkali atoms (qudits). Collective interactions are achieved through coherent quantum feedback of a laser probe, interacting with the ensemble through Faraday interaction. This process is enhanced with control of the atomic qudits, both before and after the collective interaction. Initial preparation increases the collective squeezing parameter through enhancement of resolvable quantum fluctuations, but comes at the price of increased decoherence. We find an optimal state preparation, achieving an increased squeezing parameter while remaining robust to decoherence. After the collective interaction, qudit control maps generated entanglement to different pseudo-spin subspaces where it is metrologically useful, e.g., the clock transition or the stretched state for magnetometry. These considerations highlight the unique capabilities of our platform: we can transfer correlations between subspaces to explore a wider variety of nonclassical states, with ultimate application in sensors or quantum information processors.

  4. Thermal control of the spin pumping damping in ferromagnetic/normal metal interfaces

    NASA Astrophysics Data System (ADS)

    Rezende, S. M.; Rodríguez-Suárez, R. L.; Azevedo, A.

    2014-03-01

    A model is presented for the control of the magnetic relaxation in a ferromagnetic insulator (FMI) in contact with a normal metal (NM) under a thermal gradient applied across the thickness of the bilayer. We show that the thermal gradient modifies the spin pumping damping created by the contact of the NM with the FMI. This results from the bulk magnon spin current generated through the longitudinal spin Seebeck effect that superimposes to the spin pumping current at the FMI/NM interface, changing the FMI magnetic damping. The results of the model explain the experimental data on the control of the magnetic relaxation by thermal gradients measured by the linewidth of the ferromagnetic resonance absorption and by the attenuation of spin-wave packets propagating along a film of single-crystal yttrium iron garnet covered by a very thin platinum layer. Depending on the sign of the gradient, the relaxation rate can be increased or decreased, leading in the latter case to an apparent amplification.

  5. Recent Results of Target Single-Spin Asymmetry Experiments at Jefferson Lab

    SciTech Connect

    Jiang, Xiaodong [Los Alamos National Lab

    2013-08-01

    We report recent results from Jefferson Lab Hall A “Neutron Transversity” experiment (E06-010). Transversely polarized target single-spin asymmetry AUT and beam-target double-spin asymmetry A{sub LT} have been measured in semi-inclusive deep-inelastic scattering (SIDIS) reactions on a polarized neutron ({sup 3}He) target. Collins-type and Sivers-type asymmetries have been extracted from A{sub UT} for charged pion SIDIS productions, which are sensitive to quark transversity and Sivers distributions, correspondingly. Double spin asymmetry A{sub LT} is sensitive to a specific quark transverse momentum dependent parton distribution (TMD), the so-called “ transverse helicity” (g{sub 1T} ) distributions. In addition, target single-spin asymmetries A{sub y} in inclusive electron scattering on a transversely polarized {sup 3}He target in quasi-elastic and deep inelastic kinematics were also measured in Hall A.

  6. Quantum Stirling heat engine and refrigerator with single and coupled spin systems

    NASA Astrophysics Data System (ADS)

    Huang, Xiao-Li; Niu, Xin-Ya; Xiu, Xiao-Ming; Yi, Xue-Xi

    2014-02-01

    We study the reversible quantum Stirling cycle with a single spin or two coupled spins as the working substance. With the single spin as the working substance, we find that under certain conditions the reversed cycle of a heat engine is NOT a refrigerator, this feature holds true for a Stirling heat engine with an ion trapped in a shallow potential as its working substance. The efficiency of quantum Stirling heat engine can be higher than the efficiency of the Carnot engine, but the performance coefficient of the quantum Stirling refrigerator is always lower than its classical counterpart. With two coupled spins as the working substance, we find that a heat engine can turn to a refrigerator due to the increasing of the coupling constant, this can be explained by the properties of the isothermal line in the magnetic field-entropy plane.

  7. Spin reorientation transition process in single crystal NdFeO3

    NASA Astrophysics Data System (ADS)

    Song, Gaibei; Jiang, Junjie; Kang, Baojuan; Zhang, Jincang; Cheng, Zhenxiang; Ma, Guohong; Cao, Shixun

    2015-06-01

    The spin reorientation transition in single crystal NdFeO3 is studied using AC magnetic susceptibility, hysteresis loops, and polarized terahertz (THz) time domain spectroscopy measurements. Different frequency dependence behaviors of AC susceptibility reflect that the dynamic response of magnetization inside the spin reorientation region differs from the phase outside the transition region. The magnetization hysteresis loops at different temperatures reveal that domains formed during the spin reorientation process, which coincides with the abrupt increase of AC magnetic susceptibility during the transition. In addition, temperature dependent THz wave excitation of quasi-antiferromagnetic mode indicates the process of spin reorientation as a continuous rotation of Fe3+ spins rather than a mixed phase of ?4 and ?2.

  8. Testing the validity of the single-spin approximation in inspiral-merger-ringdown waveforms

    E-print Network

    Michael Pürrer; Mark Hannam; P. Ajith; Sascha Husa

    2013-06-10

    Gravitational-wave signals from black-hole binaries with non-precessing spins are described by four parameters -- each black hole's mass and spin. It has been shown that the dominant spin effects can be modeled by a \\emph{single} spin parameter, leading to the development of several \\emph{three-parameter} waveform models. Previous studies indicate that these models should be adequate for gravitational-wave detection. In this paper we focus on the systematic biases that would result from using them to estimate binary parameters, and consider a one-parameter family of configurations at one choice of mass ratio and effective single spin. We find that for low-mass binaries within that family of configurations, where the observable waveform is dominated by the inspiral, the systematic bias in all physical parameters is smaller than the parameter uncertainty due to degeneracies between the mass ratio and the spins, at least up to signal-to-noise ratios (SNRs) of 50. For higher-mass binaries, where the merger and ringdown make a greater contribution to the observed signal, the bias in the mass ratio is comparable to its uncertainty at SNRs of only $\\sim$30, and the bias in the measurement of the total spin is \\emph{larger} than the uncertainty defined by the 90% confidence region even at an SNR of only 10. Although this bias may be mitigated in future models by a better choice of single-effective-spin parameter, these results suggest that it may be possible to accurately measure \\emph{both} black-hole spins in intermediate-mass binaries.

  9. Measurements of Kondo and Spin Splitting in Single-Electron Transistors

    Microsoft Academic Search

    A. Kogan; S. Amasha; D. Goldhaber-Gordon; G. Granger; M. A. Kastner; Hadas Shtrikman

    2004-01-01

    We measure the spin splitting in a magnetic field B of localized states in single-electron transistors using a new method, inelastic spin-flip cotunneling. Because it involves only internal excitations, this technique gives the most precise value of the Zeeman energy Delta=|g|muBB. In the same devices we also measure the splitting with B of the Kondo peak in differential conductance. The

  10. Evidence for a Single-Spin Azimuthal Asymmetry in Semi-inclusive Pion Electroproduction

    Microsoft Academic Search

    A. Airapetian; N. Akopov; M. Amarian; E. C. Aschenauer; H. Avakian; R. Avakian; A. Avetissian; E. Avetissian; B. Bains; C. Baumgarten; M. Beckmann; S. Belostotski; J. E. Belz; Th. Benisch; S. Bernreuther; N. Bianchi; J. Blouw; H. Böttcher; A. Borissov; M. Bouwhuis; J. Brack; S. Brauksiepe; B. Braun; B. Bray; St. Brons; W. Brückner; A. Brüll; E. E. Bruins; H. J. Bulten; G. P. Capitani; P. Carter; P. Chumney; E. Cisbani; G. R. Court; P. F. Dalpiaz; E. de Sanctis; D. de Schepper; E. Devitsin; P. K. de Witt Huberts; P. di Nezza; M. Düren; A. Dvoredsky; G. Elbakian; J. Ely; A. Fantoni; A. Fechtchenko; M. Ferstl; K. Fiedler; B. W. Filippone; H. Fischer; B. Fox; J. Franz; S. Frullani; M.-A. Funk; Y. Gärber; H. Gao; F. Garibaldi; G. Gavrilov; P. Geiger; V. Gharibyan; A. Golendukhin; G. Graw; O. Grebeniouk; P. W. Green; L. G. Greeniaus; C. Grosshauser; M. Guidal; A. Gute; V. Gyurjyan; J. P. Haas; W. Haeberli; J.-O. Hansen; M. Hartig; D. Hasch; O. Häusser; F. H. Heinsius; R. Henderson; M. Henoch; R. Hertenberger; Y. Holler; R. J. Holt; W. Hoprich; H. Ihssen; M. Iodice; A. Izotov; H. E. Jackson; A. Jgoun; R. Kaiser; E. Kinney; A. Kisselev; P. Kitching; H. Kobayashi; N. Koch; K. Königsmann; M. Kolstein; H. Kolster; V. Korotkov; W. Korsch; V. Kozlov; L. H. Kramer; V. G. Krivokhijine; M. Kurisuno; G. Kyle; W. Lachnit; P. Lenisa; W. Lorenzon; N. C. Makins; F. K. Martens; J. W. Martin; F. Masoli; A. Mateos; M. McAndrew; K. McIlhany; R. D. McKeown; F. Meissner; F. Menden; A. Metz; N. Meyners; O. Mikloukho; C. A. Miller; M. A. Miller; R. Milner; A. Most; V. Muccifora; R. Mussa; A. Nagaitsev; Y. Naryshkin; A. M. Nathan; F. Neunreither; M. Niczyporuk; W.-D. Nowak; M. Nupieri; K. A. Oganessyan; T. G. O'Neill; R. Openshaw; J. Ouyang; B. R. Owen; V. Papavassiliou; S. F. Pate; M. Pitt; S. Potashov; D. H. Potterveld; G. Rakness; A. Reali; R. Redwine; A. R. Reolon; R. Ristinen; K. Rith; P. Rossi; S. Rudnitsky; M. Ruh; D. Ryckbosch; Y. Sakemi; I. Savin; C. Scarlett; A. Schäfer; F. Schmidt; H. Schmitt; G. Schnell; K. P. Schüler; A. Schwind; J. Seibert; T.-A. Shibata; K. Shibatani; T. Shin; V. Shutov; C. Simani; A. Simon; K. Sinram; P. Slavich; M. Spengos; E. Steffens; J. Stenger; J. Stewart; U. Stoesslein; M. Sutter; H. Tallini; S. Taroian; A. Terkulov; O. Teryaev; E. Thomas; B. Tipton; M. Tytgat; G. M. Urciuoli; J. F. van den Brand; G. van der Steenhoven; R. van de Vyver; J. J. van Hunen; M. C. Vetterli; V. Vikhrov; M. G. Vincter; J. Visser; E. Volk; W. Wander; J. Wendland; S. E. Williamson; T. Wise; K. Woller; S. Yoneyama; H. Zohrabian

    2000-01-01

    Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle phi of the pion relative to the lepton scattering plane was formed for pi+ electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sinphi moment of the cross section

  11. Digital atom interferometer with single particle control on a discretized space-time geometry

    PubMed Central

    Steffen, Andreas; Alberti, Andrea; Alt, Wolfgang; Belmechri, Noomen; Hild, Sebastian; Karski, Micha?; Widera, Artur; Meschede, Dieter

    2012-01-01

    Engineering quantum particle systems, such as quantum simulators and quantum cellular automata, relies on full coherent control of quantum paths at the single particle level. Here we present an atom interferometer operating with single trapped atoms, where single particle wave packets are controlled through spin-dependent potentials. The interferometer is constructed from a sequence of discrete operations based on a set of elementary building blocks, which permit composing arbitrary interferometer geometries in a digital manner. We use this modularity to devise a space-time analogue of the well-known spin echo technique, yielding insight into decoherence mechanisms. We also demonstrate mesoscopic delocalization of single atoms with a separation-to-localization ratio exceeding 500; this result suggests their utilization beyond quantum logic applications as nano-resolution quantum probes in precision measurements, being able to measure potential gradients with precision 5 × 10-4 in units of gravitational acceleration g. PMID:22665771

  12. Measurement of the electron spin relaxation time in a silicon quantum dot using single-shot readout

    NASA Astrophysics Data System (ADS)

    Prance, J. R.; Simmons, C. B.; van Bael, B. J.; Seng Koh, Teck; Shi, Zhan; Savage, D. E.; Lagally, M. G.; Joynt, R.; Friesen, Mark; Coppersmith, S. N.; Eriksson, M. A.

    2011-03-01

    Electron spins in Si/SiGe quantum dots are promising candidates as qubits for quantum information processing, because spins in silicon couple weakly to the host material. We present a measurement of the spin lifetime for electrons in a silicon quantum dot. The spin state of individual electrons is measured using single-shot charge readout and spin-to-charge conversion: only spin-up electrons will tunnel off the quantum dot. Charge sensing is performed with an integrated quantum point contact that detects single electron tunnel events as steps in current. We determine the relaxation time by measuring the fraction of measurements that contain spin-up tunneling events as a function of the time that the electron spins are held on the quantum dot. We observe a clear decay in this spin-up fraction versus time, and an exponential fit yields T1 ~ 2.8 seconds at a magnetic field of 1.85 T .

  13. Spin transfer and current-induced switching in a ferromagnetic single-electron transistor

    NASA Astrophysics Data System (ADS)

    Jalil, M. B. A.; Tan, S. G.

    2005-12-01

    We propose a theoretical model of current-induced magnetization (CIMS) switching in a ferromagnetic single electron tunneling (FM-SET) transistor. The CIMS effect arises from the transfer of spin angular momentum from the net spin accumulation ?S on the island electrode to the local magnetic moments via s-d exchange coupling. Based on the single-domain model, we derive an analytical expression for the critical spin accumulation ?Ssw on the island for CIMS, and calculate the M-?S hysteresis curves which represent the effect of ?S on the island moments. This magnetization response is then related to the charge and spin transport model in the SET transistor. We extend the Korotkov scheme spin-dependent “orthodox” theory of single charge tunneling, by linking the transport I-V and ?S-V characteristics to the M-?S hysteresis. We thus determine ?S as a function of external bias or current and hence obtain the switching current density jsw for CIMS. For a typical spin polarization P=60% of the source electrode, jsw is calculated to be of the order of 105A/cm2 , and this falls to just ˜3×104A/cm2 when a near half-metal (P=90%) is used. This value is several orders of magnitude smaller than jsw observed in multilayer and magnetic tunnel junction structures. The SET transistor is an ideal device for the CIMS effect since (i) a small amount of moments (on the island) need to be switched to generate a large change in conduction and (ii) the island electrode being isolated from the rest of the circuit by spin-dependent tunnel barriers effectively confines the spin accumulation ?S in the vicinity of these moments.

  14. Soft-Fermion-Pole Mechanism to Single Spin Asymmetry in Hadronic Pion Production

    SciTech Connect

    Koike, Yuji; Tomita, Tetsuya [Department of Physics, Niigata University, Ikarashi, Niigata 950-2181 (Japan)

    2009-08-04

    Single spin asymmetry (SSA) is a twist-3 observable in the collinear factorization approach. We present a twist-3 single-spin-dependent cross section formula for the pion production in pp-collision, p{sup a}rrow upp->piX, relevant to RHIC experiments. In particular, we calculate the soft-fermion-pole (SFP) contribution to the cross section from the quark-gluon correlation functions. We show that its effect can be as large as the soft-gluon-pole (SGP) contribution owing to the large SFP partonic hard cross section, even though the derivative of the SFP function does not participate in the cross section.

  15. Single Scale Cluster Expansions with Applications to Many Boson and Unbounded Spin Systems

    E-print Network

    Martin Lohmann

    2014-11-04

    We develop a cluster expansion to show exponential decay of correlations for quite general single scale spin systems, as they arise in lattice quantum field theory and discretized functional integral representations for observables of quantum statistical mechanics. We apply our results to: the small field approximation to the coherent state correlation functions of the grand canonical Bose gas at negative chemical potential, constructed by Balaban, Feldman, Kn\\"orrer and Trubowitz (2010); and to N component unbounded spin systems with repulsive two body interaction and massive, possibly complex, covariance. Our cluster expansion is derived by a single application of the BKAR interpolation formula.

  16. Fabrication of a Spin-Polarized Electron Source with a Single Magnetite Whisker

    NASA Astrophysics Data System (ADS)

    Okada, Morihiro; Nagai, Shigekazu; Neo, Youichiro; Hata, Koichi; Mimura, Hidenori

    2009-06-01

    <110>-oriented single crystal magnetite whiskers 30 to 200 nm in diameter were synthesized on a stainless steel plate by means of the combustion flame thermal oxidation process. Microscopic analyses have revealed that the whiskers have some defects such as stacking faults and dislocations and also that manganese is the dominant impurity. A spin-polarized electron source with a single magnetite whisker was fabricated by using a micro-sampling instrument in a focused ion beam (FIB) system. The spin polarization of this sample was measured by using a Mott electron polarimeter and was found to be 15% at room temperature.

  17. Single Longitudinal-Spin Asymmetries in Lepton-Pair Production at RHIC and J-PARC

    E-print Network

    Hiroshi Yokoya

    2007-05-17

    We study the single longitudinal-spin asymmetries in lepton-pair production with large transverse-momentum at RHIC and J-PARC experiments. The asymmetries in the azimuthal angular distribution of a lepton can arise from an absorptive part of production amplitudes. We revisit the one-loop calculation for the absorptive part of production amplitudes in perturbative QCD, and show that the asymmetries can be sizable at RHIC and J-PARC. Measurement of the asymmetries would test the one-loop prediction for the scattering phase of this process, and provide support for a study of the single transverse-spin asymmetries in the same kinematical region.

  18. Single scale cluster expansions with applications to many Boson and unbounded spin systems

    NASA Astrophysics Data System (ADS)

    Lohmann, Martin

    2015-06-01

    We develop a cluster expansion to show exponential decay of correlations for quite general single scale spin systems, as they arise in lattice quantum field theory and discretized functional integral representations for observables of quantum statistical mechanics. We apply our results to the small field approximation to the coherent state correlation functions of the grand canonical Bose gas at negative chemical potential, constructed by Balaban et al. [Ann. Henri Poincaré 11, 151-350 (2010c)], and to N component unbounded spin systems with repulsive two body interaction and massive, possibly complex, covariance. Our cluster expansion is derived by a single application of the Brydges-Kennedy-Abdesselam-Rivasseau interpolation formula.

  19. Gate control of the electron spin-diffusion length in semiconductor quantum wells

    PubMed Central

    Wang, G.; Liu, B. L.; Balocchi, A.; Renucci, P.; Zhu, C. R.; Amand, T.; Fontaine, C.; Marie, X.

    2013-01-01

    The spin diffusion length is a key parameter to describe the transport properties of spin polarized electrons in solids. Electrical spin injection in semiconductor structures, a major issue in spintronics, critically depends on this spin diffusion length. Gate control of the spin diffusion length could be of great importance for the operation of devices based on the electric field manipulation and transport of electron spin. Here we demonstrate that the spin diffusion length in a GaAs quantum well can be electrically controlled. Through the measurement of the spin diffusion coefficient by spin grating spectroscopy and of the spin relaxation time by time-resolved optical orientation experiments, we show that the diffusion length can be increased by more than 200% with an applied gate voltage of 5?V. These experiments allow at the same time the direct simultaneous measurements of both the Rashba and Dresselhaus spin-orbit splittings. PMID:24052071

  20. Generation and coherent control of pure spin currents via terahertz pulses

    SciTech Connect

    Schüler, Michael, E-mail: michael.schueler@physik.uni-halle.de; Berakdar, Jamal [Institute for Physics, Martin-Luther University Halle-Wittenberg, 06099 Halle (Germany)

    2014-04-21

    We inspect the time and spin-dependent, inelastic tunneling in engineered semiconductor-based double quantum well driven by time-structured terahertz pulses. An essential ingredient is an embedded spin-active structure with vibrational modes that scatter the pulse driven carriers. Due to the different time scales of the charge and spin dynamics, the spin-dependent electron-vibron coupling may result in pure net spin current (with negligible charge current). Heating the vibrational site may affect the resulting spin current. Furthermore, by controlling the charge dynamics, the spin dynamics and the generated spin current can be manipulated and switched on and off coherently.

  1. Quantum control and measurement of spins in laser cooled gases

    NASA Astrophysics Data System (ADS)

    Deutsch, Ivan

    2012-10-01

    Quantum information processing (QIP) requires three important ingredients: (i) preparing a desired initial quantum state, usually highly pure; (ii) controlling the dynamical evolution, usually via a desired unitary transformation; (iii) measuring the desired information encoded in the final quantum state. Many physical platforms are being developed for QIP, including trapped ions, semiconductor quantum dots, and atoms in optical lattices. In these cases, it is the spins of the system that encode the quantum information. Spins are natural carriers of quantum information given their long coherence times and our ability to control them with a variety of external electromagnetic fields. In addition, spins in laser-cooled atomic gases are an excellent testbed for exploring QIP protocols because of our ability to initially prepare highly pure states and employ the well-developed tools of quantum optics and coherent spectroscopy. In this talk I will give an overview of recent theory and experiment in the control and measurement of spins in laser-cooled atomic gases. We consider the hyperfine magnetic sublevels in the ground electronic states of ^133Cs, a 16-dimensional Hilbert space. We can explore all three ingredients described above: preparation of an arbitrary superposition state, evolution through an arbitrary unitary matrix, and readout through quantum state reconstruction of the full density matrix. We employ the tools of optimal quantum control and quantum estimation theory. The implementation involves atoms controlled by radio-frequency, microwave, a optical fields, and measured via polarization spectroscopy. The experiment is performed in the group of Prof. Poul S. Jessen, University of Arizona. This work was supported by the National Science Foundation.

  2. Room-temperature coherent coupling of single spins in diamond

    Microsoft Academic Search

    Torsten Gaebel; Michael Domhan; Iulian Popa; Christoffer Wittmann; Philipp Neumann; Fedor Jelezko; James R. Rabeau; Nikolas Stavrias; Andrew D. Greentree; Steven Prawer; Jan Meijer; Jason Twamley; Philip R. Hemmer; Jörg Wrachtrup

    2006-01-01

    Coherent coupling between single quantum objects is at the very heart of modern quantum physics. When the coupling is strong enough to prevail over decoherence, it can be used to engineer quantum entangled states. Entangled states have attracted widespread attention because of applications to quantum computing and long-distance quantum communication. For such applications, solid-state hosts are preferred for scalability reasons,

  3. Circuit-quantum electrodynamics with direct magnetic coupling to single-atom spin qubits in isotopically enriched {sup 28}Si

    SciTech Connect

    Tosi, Guilherme, E-mail: g.tosi@unsw.edu.au; Mohiyaddin, Fahd A.; Morello, Andrea, E-mail: a.morello@unsw.edu.au [Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Australia, Sydney, New South Wales 2052, Australia. (Australia); Huebl, Hans [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, D-85748 Garching (Germany); Nanosystems Initiative Munich (NIM), Schellingstr. 4, D-80799 Munich, Germany. (Germany)

    2014-08-15

    Recent advances in silicon nanofabrication have allowed the manipulation of spin qubits that are extremely isolated from noise sources, being therefore the semiconductor equivalent of single atoms in vacuum. We investigate the possibility of directly coupling an electron spin qubit to a superconducting resonator magnetic vacuum field. By using resonators modified to increase the vacuum magnetic field at the qubit location, and isotopically purified {sup 28}Si substrates, it is possible to achieve coupling rates faster than the single spin dephasing. This opens up new avenues for circuit-quantum electrodynamics with spins, and provides a pathway for dispersive read-out of spin qubits via superconducting resonators.

  4. Protein carbon-13 spin systems by a single two-dimensional nuclear magnetic resonance experiment

    SciTech Connect

    Oh, B.H.; Westler, W.M.; Darba, P.; Markley, J.L.

    1988-05-13

    By applying a two-dimensional double-quantum carbon-13 nuclear magnetic resonance experiment to a protein uniformly enriched to 26% carbon-13, networks of directly bonded carbon atoms were identified by virtue of their one-bond spin-spin couplings and were classified by amino acid type according to their particular single- and double-quantum chemical shift patterns. Spin systems of 75 of the 98 amino acid residues in a protein, oxidized Anabaena 7120 ferredoxin (molecular weight 11,000), were identified by this approach, which represents a key step in an improved methodology for assigning protein nuclear magnetic resonance spectra. Missing spin systems corresponded primarily to residues located adjacent to the paramagnetic iron-sulfur cluster. 25 references, 2 figures.

  5. Spectral Line Shape and Line Width of a Single-Mode Spin Torque Oscillator

    NASA Astrophysics Data System (ADS)

    Krivorotov, Ilya; Boone, Carl; Zhu, Jian; Cheng, Xiao; Katine, Jordan; Childress, Jeff

    2009-03-01

    Spin torque auto-oscillators are strongly nonlinear dynamical systems that are highly susceptible to external perturbations such as spin-polarized current and temperature. To understand the effect of thermal fluctuations on the oscillator dynamics, we measure power spectrum of single-mode spin torque oscillators based on a GMR nanocontact to a permalloy nanowire. Our measurements reveal deviations of the power spectral line shape from a simple Lorentzian. These deviations can be understood in terms of dephasing induced by the oscillator amplitude fluctuations. The measured spectral line shape is in a good agreement with a recent analytic theory of spin torque oscillator dynamics at a non-zero temperature [1]. We show that precise measurements of the line shape give information on important oscillator parameters such as Gilbert damping in the large-amplitude regime of current-driven magnetization dynamics. [1] V. S. Tiberkevich, A. N. Slavin, J.-V. Kim, Phys. Rev. B 78, 092401 (2008).

  6. Understanding spin structure in metallacrown single-molecule magnets using magnetic compton scattering.

    PubMed

    Deb, Aniruddha; Boron, Thaddeus T; Itou, Masayoshi; Sakurai, Yoshiharu; Mallah, Talal; Pecoraro, Vincent L; Penner-Hahn, James E

    2014-04-01

    The 3d-4f mixed metallacrowns frequently show single-molecule magnetic behavior. We have used magnetic Compton scattering to characterize the spin structure and orbital interactions in three isostructural metallacrowns: Gd2Mn4, Dy2Mn4, and Y2Mn4. These data allow the direct determination of the spin only contribution to the overall magnetic moment. We find that the lanthanide 4f spin in Gd2Mn4 and Dy2Mn4 is aligned parallel to the Mn 3d spin. For Y2Mn4 (manganese-only spin) we find evidence for spin delocalization into the O 2p orbitals. Comparing the magnetic Compton scattering data with SQUID studies that measure the total magnetic moment suggests that Gd2Mn4 and Y2Mn4 have only a small orbital contribution to the moment. In contrast, the total magnetic moment for Dy2Mn4 MCs is much larger than the spin-only moment, demonstrating a significant orbital contribution to the overall magnetic moment. Overall, these data provide direct insight into the correlation of molecular design with molecular magnetic properties. PMID:24625070

  7. Nanosecond spin lifetimes in single- and few-layer graphene-hBN heterostructures at room temperature.

    PubMed

    Drögeler, Marc; Volmer, Frank; Wolter, Maik; Terrés, Bernat; Watanabe, Kenji; Taniguchi, Takashi; Güntherodt, Gernot; Stampfer, Christoph; Beschoten, Bernd

    2014-11-12

    We present a new fabrication method of graphene spin-valve devices that yields enhanced spin and charge transport properties by improving both the electrode-to-graphene and graphene-to-substrate interface. First, we prepare Co/MgO spin injection electrodes onto Si(++)/SiO2. Thereafter, we mechanically transfer a graphene-hBN heterostructure onto the prepatterned electrodes. We show that room temperature spin transport in single-, bi-, and trilayer graphene devices exhibit nanosecond spin lifetimes with spin diffusion lengths reaching 10 ?m combined with carrier mobilities exceeding 20,000 cm(2)/(V s). PMID:25291305

  8. Strong mechanical driving of a single electron spin

    E-print Network

    Barfuss, A.; Teissier, J.; Neu, E.; Nunnenkamp, A.; Maletinsky, P.

    2015-01-01

    . Jacques for fruitful discussions, P. Appel for initial assistance with nanofab- rication and L. Thiel for support with the experiment control software. We gratefully ac- knowledge financial support from SNI; NCCR QSIT; SNF grants 200021 143697; and EU FP7...

  9. Quantum non-demolition measurements of single donor spins in semiconductors

    E-print Network

    Sarovar, Mohan; Schenkel, Thomas; Whaley, K Birgitta

    2008-01-01

    We propose a scheme for measuring the state of a single donor electron spin using a field-effect transistor induced two-dimensional electron gas and electrically detected magnetic resonance techniques. The scheme is facilitated by hyperfine coupling to the donor nucleus. We analyze the potential sensitivity and outline experimental requirements. Our measurement provides a single-shot, projective, and effectively quantum non-demolition measurement of an electron-encoded qubit state.

  10. Quantum non-demolition measurements of single donor spins in semiconductors

    E-print Network

    Mohan Sarovar; Kevin C. Young; Thomas Schenkel; K. Birgitta Whaley

    2009-01-05

    We propose a technique for measuring the state of a single donor electron spin using a field-effect transistor induced two-dimensional electron gas and electrically detected magnetic resonance techniques. The scheme is facilitated by hyperfine coupling to the donor nucleus. We analyze the potential sensitivity and outline experimental requirements. Our measurement provides a single-shot, projective, and quantum non-demolition measurement of an electron-encoded qubit state.

  11. Initial-State Interactions and Single-Spin Asymmetries in Drell-Yan Processes

    SciTech Connect

    Brodsky, Stanley J.

    2002-06-26

    We show that the initial-state interactions from gluon exchange between the incoming quark and the target spectator system lead to leading-twist single-spin asymmetries in the Drell-Yan process H{sub 1}H{sub 2}{sup {up_arrow}} {yields} {ell}{sup +}{ell}{sup -}X. The QCD initial-state interactions produce a T-odd spin-correlation {rvec S}{sub H{sub 2}} {center_dot} {rvec P}{sub H{sub 1}} x {rvec Q} between the target spin and the virtual photon production plane which is not power-law suppressed in the Drell-Yan scaling limit at large photon virtuality Q{sup 2} at fixed x{sub F}. The single-spin asymmetry which arises from the initial-state interactions is not related to the target or projectile transversity distribution {delta}q{sub H}. The origin of the single-spin asymmetry in {pi}p{up_arrow} {ell}{sup +}{ell}{sup -} is a phase difference between two amplitudes coupling the proton target with J{sub p}{sup z} = {+-} 1/2 to the same final-state, the same amplitudes which are necessary to produce a nonzero proton anomalous magnetic moment. The calculation requires the overlap of target light-front wavefunctions with different orbital angular momentum: {Delta}L{sup z} = 1; thus the SSA in the Drell-Yan reaction provides a direct measure of orbital angular momentum in the QCD bound state. The single-spin asymmetry predicted for the Drell-Yan process {pi}p{up_arrow} {yields} {ell}{sup +}{ell}{sup -}X is similar to the single-spin asymmetries in deep inelastic semi-inclusive leptoproduction {ell}p{up_arrow} {yields} {ell}{prime}{pi}X which arises from the final-state rescattering of the outgoing quark. The Bjorken-scaling single-spin asymmetries predicted for the Drell-Yan and leptoproduction processes high-light the importance of initial- and final-state interactions for QCD observables.

  12. Quantum registers based on single NV + n 13 C centers in diamond: I. The spin Hamiltonian method

    Microsoft Academic Search

    A. P. Nizovtsev; S. Ya. Kilin; V. A. Pushkarchuk; A. L. Pushkarchuk; S. A. Kuten’

    2010-01-01

    Details of the application of the spin Hamiltonian method for studying spin characteristics of a quantum register that includes\\u000a an electron spin S = 1 of a single NV center in the ground electronic state and nuclear spins I = 1\\/2 of several isotopic atoms 13C located at different lattice sites near the vacancy of the NV center. Two methods

  13. Single spin asymmetries in p\\uparrow p rightarrow ? X and bar{p} \\uparrow p rightarrow ? X

    NASA Astrophysics Data System (ADS)

    Zacarias, G. Domínguez; Herrera, G.; León-Monzón, I.

    2001-05-01

    We study the inclusive production of charged and neutral pions in the reactions p \\uparrow p rightarrow ? X and bar{p} \\uparrow p rightarrow ? X in the framework of single spin asymmetries. We propose a two components model where production of pions occurs both by recombination of the constituents present in the initial state and by fragmentation of quarks in the final state. Taking the Thomas precession mechanism in the recombination component into account, we obtain a good description of the experimentally observed single spin asymmetries. We show that the observed single spin asymmetries are consistent with the measured spin alignment in the polarized proton as measured by HERMES and SMC.

  14. Spin Filtering and Entanglement Swapping through Coherent Evolution of a Single Quantum Dot

    Microsoft Academic Search

    Jose Garcia Coello; Abolfazl Bayat; Sougato Bose; John H. Jefferson; Charles E. Creffield

    2010-01-01

    We exploit the non-dissipative dynamics of a pair of electrons in a large square quantum dot to perform singlet-triplet spin measurement through a single charge detection and show how this may be used for entanglement swapping and teleportation. The method is also used to generate the AKLT ground state, a further resource for quantum computation. We justify, and derive analytic

  15. Controllable spin-charge transport in strained graphene nanoribbon devices

    NASA Astrophysics Data System (ADS)

    Diniz, Ginetom S.; Guassi, Marcos R.; Qu, Fanyao

    2014-09-01

    We theoretically investigate the spin-charge transport in two-terminal device of graphene nanoribbons in the presence of a uniform uniaxial strain, spin-orbit coupling, exchange field, and smooth staggered potential. We show that the direction of applied strain can efficiently tune strain-strength induced oscillation of band-gap of armchair graphene nanoribbon (AGNR). It is also found that electronic conductance in both AGNR and zigzag graphene nanoribbon (ZGNR) oscillates with Rashba spin-orbit coupling akin to the Datta-Das field effect transistor. Two distinct strain response regimes of electronic conductance as function of spin-orbit couplings magnitude are found. In the regime of small strain, conductance of ZGNR presents stronger strain dependence along the longitudinal direction of strain. Whereas for high values of strain shows larger effect for the transversal direction. Furthermore, the local density of states shows that depending on the smoothness of the staggered potential, the edge states of AGNR can either emerge or be suppressed. These emerging states can be determined experimentally by either spatially scanning tunneling microscope or by scanning tunneling spectroscopy. Our findings open up new paradigms of manipulation and control of strained graphene based nanostructure for application on novel topological quantum devices.

  16. Controllable spin-charge transport in strained graphene nanoribbon devices

    SciTech Connect

    Diniz, Ginetom S., E-mail: ginetom@gmail.com; Guassi, Marcos R. [Institute of Physics, University of Brasília, 70919-970, Brasília-DF (Brazil); Qu, Fanyao [Institute of Physics, University of Brasília, 70919-970, Brasília-DF (Brazil); Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2014-09-21

    We theoretically investigate the spin-charge transport in two-terminal device of graphene nanoribbons in the presence of a uniform uniaxial strain, spin-orbit coupling, exchange field, and smooth staggered potential. We show that the direction of applied strain can efficiently tune strain-strength induced oscillation of band-gap of armchair graphene nanoribbon (AGNR). It is also found that electronic conductance in both AGNR and zigzag graphene nanoribbon (ZGNR) oscillates with Rashba spin-orbit coupling akin to the Datta-Das field effect transistor. Two distinct strain response regimes of electronic conductance as function of spin-orbit couplings magnitude are found. In the regime of small strain, conductance of ZGNR presents stronger strain dependence along the longitudinal direction of strain. Whereas for high values of strain shows larger effect for the transversal direction. Furthermore, the local density of states shows that depending on the smoothness of the staggered potential, the edge states of AGNR can either emerge or be suppressed. These emerging states can be determined experimentally by either spatially scanning tunneling microscope or by scanning tunneling spectroscopy. Our findings open up new paradigms of manipulation and control of strained graphene based nanostructure for application on novel topological quantum devices.

  17. Controlled synthesis of single-crystalline graphene

    SciTech Connect

    Xueshen, Wang, E-mail: wangxs@nim.ac.cn; Jinjin, Li, E-mail: jinjinli@nim.ac.cn; Qing, Zhong; Yuan, Zhong; Mengke, Zhao; Yonggang, Liu [National Institute of Metrology, Beijing, China, 100013 (China)] [National Institute of Metrology, Beijing, China, 100013 (China)

    2014-03-15

    This paper reports the controlled synthesis of single-crystalline graphene on the back side of copper foil using CH{sub 4} as the precursor. The influence of growth time and the pressure ratio of CH{sub 4}/H{sub 2} on the structure of graphene are examined. An optimized polymer-assisted method is used to transfer the synthesized graphene onto a SiO{sub 2}/Si substrate. Scanning electron microscopy and Raman spectroscopy are used to characterize the graphene.

  18. Dynamics and Control of a Quasi-1D Spin System

    E-print Network

    Paola Cappellaro; Chandrasekhar Ramanathan; David G. Cory

    2007-06-04

    We study experimentally a system comprised of linear chains of spin-1/2 nuclei that provides a test-bed for multi-body dynamics and quantum information processing. This system is a paradigm for a new class of quantum information devices that can perform particular tasks even without universal control of the whole quantum system. We investigate the extent of control achievable on the system with current experimental apparatus and methods to gain information on the system state, when full tomography is not possible and in any case highly inefficient.

  19. Adaptive Power Control for Single and Multiuser Opportunistic Systems

    E-print Network

    Nam, Sung Sik

    2010-07-14

    In this dissertation, adaptive power control for single and multiuser opportunistic systems is investigated. First, a new adaptive power-controlled diversity combining scheme for single user systems is proposed, upon which is extended...

  20. Dynamics of a Mn spin coupled to a single hole confined in a quantum dot

    NASA Astrophysics Data System (ADS)

    Varghese, B.; Boukari, H.; Besombes, L.

    2014-09-01

    Using the emission of the positively charged exciton as a probe, we analyze the dynamics of the optical pumping and the dynamics of the relaxation of a Mn spin exchange coupled with a confined hole spin in a II-VI semiconductor quantum dot. The hole-Mn spin can be efficiently initialized in a few tens of ns under optical injection of spin-polarized carriers. We show that this optical pumping process and its dynamics are controlled by electron-Mn flip-flops within the positively charged exciton-Mn complex. The pumping mechanism and its magnetic field dependence are theoretically described by a model including the dynamics of the electron-Mn complex in the excited state and the dynamics of the hole-Mn complex in the ground state of the positively charged quantum dot. We measure at zero magnetic field a spin-relaxation time of the hole-Mn spin in the ?s range or shorter. This hole-Mn spin relaxation is induced by the presence of valence-band mixing in self-assembled quantum dots.

  1. Sub-optical resolution of single spins using magnetic resonance imaging at room temperature in diamond

    E-print Network

    Chang Shin; Changdong Kim; Roman Kolesov; Gopalakrishnan Balasubramanian; Fedor Jelezko; Jörg Wrachtrup; Philip R. Hemmer

    2010-03-29

    There has been much recent interest in extending the technique of magnetic resonance imaging (MRI) down to the level of single spins with sub-optical wavelength resolution. However, the signal to noise ratio for images of individual spins is usually low and this necessitates long acquisition times and low temperatures to achieve high resolution. An exception to this is the nitrogen-vacancy (NV) color center in diamond whose spin state can be detected optically at room temperature. Here we apply MRI to magnetically equivalent NV spins in order to resolve them with resolution well below the optical wavelength of the readout light. In addition, using a microwave version of MRI we achieved a resolution that is 1/270 size of the coplanar striplines, which define the effective wavelength of the microwaves that were used to excite the transition. This technique can eventually be extended to imaging of large numbers of NVs in a confocal spot and possibly to image nearby dark spins via their mutual magnetic interaction with the NV spin.

  2. Spin-1 atoms in optical superlattices: Single-atom tunneling and entanglement

    SciTech Connect

    Wagner, Andreas; Bruder, Christoph; Demler, Eugene [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2011-12-15

    We examine spinor Bose-Einstein condensates in optical superlattices theoretically using a Bose-Hubbard Hamiltonian that takes spin effects into account. Assuming that a small number of spin-1 bosons is loaded in an optical potential, we study single-particle tunneling that occurs when one lattice site is ramped up relative to a neighboring site. Spin-dependent effects modify the tunneling events in a qualitative and quantitative way. Depending on the asymmetry of the double well, different types of magnetic order occur, making the system of spin-1 bosons in an optical superlattice a model for mesoscopic magnetism. We use a double-well potential as a unit cell for a one-dimensional superlattice. Homogeneous and inhomogeneous magnetic fields are applied, and the effects of the linear and the quadratic Zeeman shifts are examined. We also investigate the bipartite entanglement between the sites and construct states of maximal entanglement. The entanglement in our system is due to both orbital and spin degrees of freedom. We calculate the contribution of orbital and spin entanglements and show that the sum of these two terms gives a lower bound for the total entanglement.

  3. Stability of spin-electric coupling in triangular single-molecule magnets under external contacts

    NASA Astrophysics Data System (ADS)

    Islam, Fhokrul; Nossa, Javier; Canali, Carlo; Pederson, Mark

    2015-03-01

    Triangular single molecule magnets (SMMs) with antiferromagnetic exchange coupling exhibit Kramer degenerate chiral spin-doublets ground states, which can be efficiently coupled by an electric field, even in the absence of spin-orbit interaction. Recent first-principles calculations show that unsupported V3 SMM has giant spin-electric coupling corresponding to dipole moment of about one tenth of the water-molecule dipole moment. The corresponding Rabi time for electric switching between two chiral states can be on the order of one nano-second for reasonable electric fields, which makes these molecules very attractive candidates for storing and manipulating pairs of coupled spin-chiral qbits. However, for device applications of the spin-electric coupling, these frustrated SMMs need to be supported on a surface or between metallic leads. Preserving this effect in an external environment is a challenging problem requiring appropriate functionalization. In this talk we will discuss the stability of the spin-electric coupling in V3 SMM when coupled to gold leads or deposited on a graphene surface.

  4. Large-Spin and Large-Winding Expansions of Giant Magnons and Single Spikes

    E-print Network

    Emmanuel Floratos; Georgios Linardopoulos

    2015-05-30

    We generalize the method of our recent paper on the large-spin expansions of Gubser-Klebanov-Polyakov (GKP) strings to the large-spin and large-winding expansions of finite-size giant magnons and finite-size single spikes. By expressing the energies of long open strings in RxS2 in terms of Lambert's W-function, we compute the leading, subleading and next-to-subleading series of classical exponential corrections to the dispersion relations of Hofman-Maldacena giant magnons and infinite-winding single spikes. We also compute the corresponding expansions in the doubled regions of giant magnons and single spikes that are respectively obtained when their angular and linear velocities become smaller or greater than unity.

  5. Synthesis of matched magnetic fields for controlled spin precession

    NASA Astrophysics Data System (ADS)

    Bouchard, Louis-S.; Anwar, M. Sabieh

    2007-07-01

    The shaping of magnetic fields is important in many areas of physics, including magnet shimming, electromagnetic traps, magnetic domain switching, and controlled spin precession in nuclear magnetic resonance (NMR). We examine the method of target field matching by orthogonal projection and its application to NMR, whereby the phase of nuclear spins in a strongly inhomogeneous field is corrected through stroboscopic ac irradiation using matching fields. Three-dimensional shaping of static and ac fields can restore the spectral resolution by orders of magnitude using simple linear combinations of a small number of independent sources. Results suggest the possibility of substantially pushing the current limits of high-resolution NMR spectroscopy in weak and inhomogeneous fields. We also discuss conditions under which concomitant gradient effects are important in high magnetic fields and the geometric-phase errors they introduce during precession in ac fields.

  6. Coherent control of hyperfine-coupled electron and nuclear spins for quantum information processing

    E-print Network

    Yang, Jamie Chiaming

    2008-01-01

    Coupled electron-nuclear spins are promising physical systems for quantum information processing: By combining the long coherence times of the nuclear spins with the ability to initialize, control, and measure the electron ...

  7. Final-state interaction as origin of single-spin asymmetry in semi-inclusive DIS

    SciTech Connect

    Hwang, D.S. [Department of Physics, Sejong University, Seoul 143-747 (Korea, Republic of)

    2005-05-06

    Recent measurements from the HERMES, SMC, CLAS and COMPASS collaborations show a remarkably large azimuthal single-spin asymmetries of the proton in semi-inclusive pion leptoproduction {gamma}*(q)p{up_arrow} {yields} {pi}X. The existence of such single-spin asymmetries requires a phase difference between two amplitudes coupling the proton target with J{sub p}{sup z} = {+-}(1/2) to the same final-state, the same amplitudes which are necessary to produce a nonzero proton anomalous magnetic moment. We show that the exchange of gauge particles between the outgoing quark and the proton spectators produces a Coulomb-like complex phase which depends on the angular momentum Lz of the proton's constituents and is thus distinct for different proton spin amplitudes. We then find that final-state interactions from gluon exchange between the outgoing quark and the target spectator system lead to single-spin asymmetries at leading twist in perturbative QCD; i.e., the rescattering corrections are not power-law suppressed at large photon virtuality Q2 at fixed xbj.

  8. Single-shot readout and relaxation measurements in exchange coupled 31 P electron spins in silicon

    NASA Astrophysics Data System (ADS)

    Dehollain, Juan Pablo; Muhonen, Juha; Tan, Kuan; Saraiva, Andre; Jamieson, David; Dzurak, Andrew; Morello, Andrea

    2015-03-01

    We present the experimental observation of a large exchange coupling J ~ 300 ?eV between two 31 P electron spin qubits in silicon. The singlet and triplet states of the coupled spins are monitored in real time by a single-electron transistor, which detects ionization from tunnel-rate-dependent processes in the coupled spin system, yielding single-shot readout fidelities above 95%. The triplet to singlet relaxation time T1 ~ 4 ms at zero magnetic field agrees with the theoretical prediction for the observed J-coupling energy in 31 P dimers in silicon. The three order of magnitude increase in relaxation rate compared to single donors, is caused by a hyperfine interaction mediated mixing of the singlet and triplet states. Additionally, the time evolution of the two-electron state populations reveals an inversion in the energetic hierarchy of the valley-orbit excited states, which had been theoretically predicted for donor pairs with < 6 nm separation. These results pave the way to the realization of two-qubit quantum logic gates with spins in silicon and highlight the necessity to adopt gating schemes compatible with weak J-coupling strengths.

  9. Electronic spin transport and spin precession in single graphene layers at room temperature

    Microsoft Academic Search

    Nikolaos Tombros; Csaba Jozsa; Mihaita Popinciuc; Harry T. Jonkman; Bart J. van Wees

    2007-01-01

    Electronic transport in single or a few layers of graphene is the subject of intense interest at present. The specific band structure of graphene, with its unique valley structure and Dirac neutrality point separating hole states from electron states, has led to the observation of new electronic transport phenomena such as anomalously quantized Hall effects, absence of weak localization and

  10. Transverse single spin asymmetry in Drell-Yan production in polarized pA collisions

    E-print Network

    Zhou, Jian

    2015-01-01

    We study the transverse single spin asymmetry in Drell-Yan production in pA collisions with incoming protons being transversely polarized. We carry out the calculation using a newly developed hybrid approach. The polarized cross section computed in the hybrid approach is consistent with that obtained from the usual TMD factorization at low transverse momentum as expected, whereas at high transverse momentum, color entanglement effect is found to play a role in contributing to the spin asymmetry of Drell-Yan production, though it is a $1/N_c^2$ suppressed effect.

  11. Observation of a Single-Spin Azimuthal Asymmetry in Semi-Inclusive Pion Electro-Production

    Microsoft Academic Search

    A. Airapetian; N. Akopov; M. Amarian; E. C. Aschenauer; H. Avakian; R. Avakian; A. Avetissian; E. Avetissian; B. Bains; C. Baumgarten; M. Beckmann; S. Belostotski; J. E. Belz; S. Bernreuther; N. Bianchi; J. Blouw; H. Bottcher; A. Borissov; M. Bouwhuis; J. Brack; S. Brauksiepe; B. Braun; B. Bray; W. Bruckner; A. Brull; E. E. W. Bruins; H. J. Bulten; G. P. Capitani; P. Chumney; E. Cisbani; P. F. Dalpiaz; E. De Sanctis; D. De Schepper; E. Devitsin; A. Dvoredsky; G. Elbakian; J. Ely; A. Fantoni; A. Fechtchenko; M. Ferstl; K. Fiedler; B. W. Filippone; H. Fischer; B. Fox; J. Franz; S. Frullani; M.-A. Funk; Y. Garber; H. Gao; F. Garibaldi; G. Gavrilov; P. Geiger; V. Gharibyan; A. Golendukhin; G. Graw; O. Grebeniouk; L. G. Greeniaus; C. Grosshauser; M. Guidal; A. Gute; V. Gyurjyan; W. Haeberli; J.-O. Hansen; M. Hartig; D. Hasch; O. Hausser; F. H. Heinsius; R. Henderson; M. Henoch; R. Hertenberger; Y. Holler; R. J. Holt; W. Hoprich; H. Ihssen; M. Iodice; A. Izotov; H. E. Jackson; A. Jgoun; R. Kaiser; E. Kinney; A. Kisselev; P. Kitching; H. Kobayashi; N. Koch; K. Konigsmann; M. Kolstein; H. Kolster; V. Korotkov; W. Korsch; V. Kozlov; L. H. Kramer; V. G. Krivokhijine; M. Kurisuno; G. Kyle; W. Lachnit; P. Lenisa; W. Lorenzon; N. C. R. Makins; F. K. Martens; J. W. Martin; F. Masoli; A. Mateos; M. McAndrew; K. McIlhany; R. D. McKeown; F. Meissner; A. Metz; N. Meyners; O. Mikloukho; C. A. Miller; M. A. Miller; R. Milner; V. Muccifora; R. Mussa; A. Nagaitsev; Y. Naryshkin; A. M. Nathan; F. Neunreither; M. Niczyporuk; W.-D. Nowak; M. Nupieri; K. A. Oganessyan; T. G. O'Neill; R. Openshaw; J. Ouyang; B. R. Owen; V. Papavassiliou; S. F. Pate; M. Pitt; S. Potashov; D. H. Potterveld; G. Rakness; A. Reali; R. Redwine; A. R. Reolon; R. Ristinen; K. Rith; P. Rossi; S. Rudnitsky; M. Ruh; D. Ryckbosch; Y. Sakemi; I. Savin; C. Scarlett; A. Schafer; F. Schmidt; H. Schmitt; G. Schnell; K. P. Schuler; A. Schwind; J. Seibert; T.-A. Shibata; K. Shibatani; T. Shin; V. Shutov; C. Simani; A. Simon; K. Sinram; P. Slavich; M. Spengos; E. Steens; J. Stenger; J. Stewart; U. Stoesslein; M. Sutter; H. Tallini; S. Taroian; A. Terkulov; O. Teryaev; E. Thomas; B. Tipton; M. Tytgat; G. M. Urciuoli; G. van der Steenhoven; R. van de Vyver; J. J. van Hunen; M. C. Vetterli; V. Vikhrov; M. G. Vincter; J. Visser; E. Volk; W. Wander; J. Wendland; S. E. Williamson; T. Wise; K. Woller; S. Yoneyama; H. Zohrabian

    1999-01-01

    Single-spin asymmetries for semi-inclusive pion production in deep-inelastic\\u000ascattering have been measured for the first time. A significant target-spin\\u000aasymmetry of the distribution in the azimuthal angle phi of the pion relative\\u000ato the lepton scattering plane was observed for pi+ electro-production on a\\u000alongitudinally polarized hydrogen target. The corresponding analyzing power in\\u000athe sin(phi) moment of the cross section

  12. Counter-diabatic driving for fast spin control in a two-electron double quantum dot.

    PubMed

    Ban, Yue; Chen, Xi

    2014-01-01

    The techniques of shortcuts to adiabaticity have been proposed to accelerate the "slow" adiabatic processes in various quantum systems with the applications in quantum information processing. In this paper, we study the counter-diabatic driving for fast adiabatic spin manipulation in a two-electron double quantum dot by designing time-dependent electric fields in the presence of spin-orbit coupling. To simplify implementation and find an alternative shortcut, we further transform the Hamiltonian in term of Lie algebra, which allows one to use a single Cartesian component of electric fields. In addition, the relation between energy and time is quantified to show the lower bound for the operation time when the maximum amplitude of electric fields is given. Finally, the fidelity is discussed with respect to noise and systematic errors, which demonstrates that the decoherence effect induced by stochastic environment can be avoided in speeded-up adiabatic control. PMID:25174453

  13. Flight investigation of stall, spin and recovery characteristics of a low-wing, single-engine, T-tail light airplane

    NASA Technical Reports Server (NTRS)

    Stough, H. P., III; Dicarlo, D. J.; Patton, J. M., Jr.

    1985-01-01

    Flight tests were performed to investigate the stall, spin, and recovery characteristics of a four-place, low-wing, single-engine, T-tail, general aviation research airplane at an aft center-of-gravity position. Most stalls resulted in roll-offs. Spins were oscillatory in roll and pitch at 43 deg angle of attack; the magnitude of the oscillations was determined by aileron position. Power, flap deflection, and landing gear position did not affect the angle of attack to the spin. Antispin rudder followed by forward wheel with ailerons neutral produced the fastest and most consistent recoveries but the initial application of recovery controls did not always stop a spin.

  14. Measurement of Single and Double Spin Asymmetries in Deep Inelastic Pion Electroproduction with a Longitudinally Polarized Target

    SciTech Connect

    Avakian, H; Bosted, P; Elouadrhiri, L; Adhikari, K P; Aghasyan, M; Amaryan, M; Anghinolfi, M; Baghdasaryan, H; Ball, J; Battaglieri, M; Bedlinskiy, I; Biselli, A S; Branford, D; Briscoe, W J; Brooks, W; Carman, D S; Casey, L; Cole, P L; Collins, P; Crabb, D; Crede, V; D& #x27; Angelo, A; Daniel, A; Dashyan, N; DeVita, R; DeSanctis, E; Deur, A; Dey, B; Dhamija, S; Dickson, R; Djalali, C; Dodge, G; Doughty, D; Dupre, R; El Alaoui, A; Eugenio, P; Fegan, S; Fersch, M; Guler, N; Guo, L; Hafidi, K; Hakobyan, H; Hanretty, C; Hassall, N; Heddle, D; Hicks, K; Holtrop, M; Ilieva, Y; Ireland, D G; Isupov, E L; Jawalkar, S S; Jo, H S; Joo, K; Keller, D; Khandaker, M; Khetarpal,; Kim, W; Klein, A; Klein, F J; Konczykowski, P; Kubarovsky, V; Kuhn, S E; Kuleshov, S V; Kuznetsov, V; Livingston, K; Lu, H Y; Markov, N; Mayer, M; McAndrew, J; McCracken, M E; McKInnon, B; Meyer, C A; Mineeva, T; Mirazita, M; Mokeev, V; Moreno, B; Moriya, K; Morrison, B; Moutarde, H; Munevar, E; Nadel-Turonski, P; Nasseripour, R; Niccolai, S; Niculescu, G; Niculescu, I; Niroula, M R; Osipenko, M; Ostrovidov, A I; Paremuzyan, R; Park, K; Park, S; Pasyuk, E; Anefalos Pereira, S; Perrin, Y; Pisano, S; Pogorelko, O; Price, J W; Procureur, S; Prok, Protopopescu; Raue, B A; Ricco, G; Ripani, M; Rosner, G; Rossi, P; Sabatie, F; Saini, M S; Salamanca, J; Salgado, C; Schumacher, R A; Seder, E; Seraydaryan, H; Sharabian, Y G; Sober, D I; Sokhan, D; Stapanyan, S S; Stepanyan, S; Stoler, P; Strauch, S; Suleiman, R; Taiuti, M; Tedeschi, D J; Tkachenko, S; Ungaro, M; Vernarsky, B; Vineyard, M F; Voutier, E; Watts, D P; Weinstein, L B; Weygand, D P; Wood, M H; Zhang, J; Zhao, B

    2010-12-01

    We report the first measurement of the transverse momentum dependence of double spin asymmetries in semi-inclusive production of pions in deep inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Thomas Jefferson National Accelerator Facility (JLab). A significant non-zero $\\sin2\\phi$ single spin asymmetry was also observed for the first time indicating strong spin-orbit correlations for transversely polarized quarks in the longitudinally polarized proton. The azimuthal modulations of single spin asymmetries have been measured over a wide kinematic range.

  15. Evidence for a Single-Spin Azimuthal Asymmetry in Semi-inclusive Pion Electroproduction

    SciTech Connect

    Airapetian, A. [Yerevan Physics Institute, 375036, Yerevan, (Armenia)] [Yerevan Physics Institute, 375036, Yerevan, (Armenia); Akopov, N. [Yerevan Physics Institute, 375036, Yerevan, (Armenia)] [Yerevan Physics Institute, 375036, Yerevan, (Armenia); Amarian, M. [Nationaal Instituut voor Kernfysica en Hoge-Energiefysica (NIKHEF), 1009 DB Amsterdam, The Netherlands (Netherlands) [Nationaal Instituut voor Kernfysica en Hoge-Energiefysica (NIKHEF), 1009 DB Amsterdam, The Netherlands (Netherlands); Istituto Nazionale di Fisica Nucleare, Sezione Sanita and Physics Laboratory, Istituto Superiore di Sanita, 00161 Roma, (Italy); Yerevan Physics Institute, 375036, Yerevan, (Armenia); Aschenauer, E. C. [Department of Subatomic and Radiation Physics, University of Gent, 9000 Gent, (Belgium) [Department of Subatomic and Radiation Physics, University of Gent, 9000 Gent, (Belgium); Max-Planck-Institut fuer Kernphysik, 69029 Heidelberg, (Germany); DESY Zeuthen, 15738 Zeuthen, (Germany); Avakian, H. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, 00044 Frascati, (Italy)] [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, 00044 Frascati, (Italy); Avakian, R. [Yerevan Physics Institute, 375036, Yerevan, (Armenia)] [Yerevan Physics Institute, 375036, Yerevan, (Armenia); Avetissian, A. [Yerevan Physics Institute, 375036, Yerevan, (Armenia)] [Yerevan Physics Institute, 375036, Yerevan, (Armenia); Avetissian, E. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, 00044 Frascati, (Italy) [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, 00044 Frascati, (Italy); Bains, B. [Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States)] [Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States); Baumgarten, C. [Sektion Physik, Universitaet Muenchen, 85748 Garching, (Germany)] (and others) [Sektion Physik, Universitaet Muenchen, 85748 Garching, (Germany)

    2000-05-01

    Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured for the first time. A significant target-spin asymmetry of the distribution in the azimuthal angle {phi} of the pion relative to the lepton scattering plane was formed for {pi}{sup +} electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power in the sin {phi} moment of the cross section is 0.022{+-}0.005{+-}0.003 . This result can be interpreted as the effect of terms in the cross section involving chiral-odd spin distribution functions in combination with a chiral-odd fragmentation function that is sensitive to the transverse polarization of the fragmenting quark. (c) 2000 The American Physical Society.

  16. Quantum electronics. Probing Johnson noise and ballistic transport in normal metals with a single-spin qubit.

    PubMed

    Kolkowitz, S; Safira, A; High, A A; Devlin, R C; Choi, S; Unterreithmeier, Q P; Patterson, D; Zibrov, A S; Manucharyan, V E; Park, H; Lukin, M D

    2015-03-01

    Thermally induced electrical currents, known as Johnson noise, cause fluctuating electric and magnetic fields in proximity to a conductor. These fluctuations are intrinsically related to the conductivity of the metal. We use single-spin qubits associated with nitrogen-vacancy centers in diamond to probe Johnson noise in the vicinity of conductive silver films. Measurements of polycrystalline silver films over a range of distances (20 to 200 nanometers) and temperatures (10 to 300 kelvin) are consistent with the classically expected behavior of the magnetic fluctuations. However, we find that Johnson noise is markedly suppressed next to single-crystal films, indicative of a substantial deviation from Ohm's law at length scales below the electron mean free path. Our results are consistent with a generalized model that accounts for the ballistic motion of electrons in the metal, indicating that under the appropriate conditions, nearby electrodes may be used for controlling nanoscale optoelectronic, atomic, and solid-state quantum systems. PMID:25636797

  17. Chip-Scale Nanofabrication of Single Spins and Spin Arrays in Diamond

    SciTech Connect

    Toyli, David M.; Weis, Christoph D.; Fuchs, D.; Schenkel, Thomas; Awschalom, David D.

    2010-07-02

    We demonstrate a technique to nanofabricate nitrogen vacancy (NV) centers in diamond based on broad-beam nitrogen implantation through apertures in electron beam lithography resist. This method enables high-throughput nanofabrication of single NV centers on sub-100-nm length scales. Secondary ion mass spectroscopy measurements facilitate depth profiling of the implanted nitrogen to provide three-dimensional characterization of the NV center spatial distribution. Measurements of NV center coherence with on-chip coplanar waveguides suggest a pathway for incorporating this scalable nanofabrication technique in future quantum applications.

  18. Multi-sensor single-actuator control of HVAC systems

    E-print Network

    Lin, Craig; Federspiel, Clifford C; Auslander, David M

    2002-01-01

    sensor, single-actuator control of temperature in buildingssensors such as those used to control space temperature in commercial buildings.sensor; HVAC; control system; optimization; multi-channel sensing system; Conference for Enhanced Building

  19. High-efficiency resonant amplification of weak magnetic fields for single spin magnetometry at room temperature

    NASA Astrophysics Data System (ADS)

    Trifunovic, Luka; Pedrocchi, Fabio L.; Hoffman, Silas; Maletinsky, Patrick; Yacoby, Amir; Loss, Daniel

    2015-06-01

    Magnetic resonance techniques not only provide powerful imaging tools that have revolutionized medicine, but they have a wide spectrum of applications in other fields of science such as biology, chemistry, neuroscience and physics. However, current state-of-the-art magnetometers are unable to detect a single nuclear spin unless the tip-to-sample separation is made sufficiently small. Here, we demonstrate theoretically that by placing a ferromagnetic particle between a nitrogen–vacancy magnetometer and a target spin, the magnetometer sensitivity is improved dramatically. Using materials and techniques that are already experimentally available, our proposed set-up is sensitive enough to detect a single nuclear spin within ten milliseconds of data acquisition at room temperature. The sensitivity is practically unchanged when the ferromagnet surface to the target spin separation is smaller than the ferromagnet lateral dimensions; typically about a tenth of a micrometre. This scheme further benefits when used for nitrogen–vacancy ensemble measurements, enhancing sensitivity by an additional three orders of magnitude.

  20. High-efficiency resonant amplification of weak magnetic fields for single spin magnetometry at room temperature.

    PubMed

    Trifunovic, Luka; Pedrocchi, Fabio L; Hoffman, Silas; Maletinsky, Patrick; Yacoby, Amir; Loss, Daniel

    2015-06-01

    Magnetic resonance techniques not only provide powerful imaging tools that have revolutionized medicine, but they have a wide spectrum of applications in other fields of science such as biology, chemistry, neuroscience and physics. However, current state-of-the-art magnetometers are unable to detect a single nuclear spin unless the tip-to-sample separation is made sufficiently small. Here, we demonstrate theoretically that by placing a ferromagnetic particle between a nitrogen-vacancy magnetometer and a target spin, the magnetometer sensitivity is improved dramatically. Using materials and techniques that are already experimentally available, our proposed set-up is sensitive enough to detect a single nuclear spin within ten milliseconds of data acquisition at room temperature. The sensitivity is practically unchanged when the ferromagnet surface to the target spin separation is smaller than the ferromagnet lateral dimensions; typically about a tenth of a micrometre. This scheme further benefits when used for nitrogen-vacancy ensemble measurements, enhancing sensitivity by an additional three orders of magnitude. PMID:25961508

  1. Cotunneling signatures of spin-electric coupling in frustrated triangular single-molecule magnets

    NASA Astrophysics Data System (ADS)

    Nossa, Javier; Canali, Carlo

    2013-03-01

    The ground state (GS) of frustrated (antiferromagnetic) triangular single-molecule magnets is characterized by two total-spin S = 1 /2 doublets with opposite chirality. According to a group theory analysis [M. Trif et al., Phys. Rev. Lett. 101, 217201 (2008)] an external electric field can efficiently couple these two chiral spin states, even when the spin-orbit interaction (SOI) is absent. The strength of this coupling, d, is determined by an off-diagonal matrix element of the dipole operator, which can be calculated by ab-initio methods [M. F. Islam et al., Phys. Rev. B 82, 155446 (2010)]. In this work we propose that Coulomb-blockade transport experiments in the cotunneling regime can provide a direct way to determine the spin-electric coupling strength. Indeed, an electric field generates a d-dependent splitting of the GS manifold, which can be detected in the inelastic cotunneling conductance. Our theoretical analysis is supported by master-equation calculations of quantum transport in the cotunneling regime. We employ a Hubbard-model approach to elucidate the relationship between the Hubbard parameters t and U, and the spin-electric coupling constant d . This allows us to predict the regime in which the coupling constant d can be extracted from experiment.

  2. Electron Spin Resonance of Irradiated Single Crystals of l-phenylalanine-HCl

    Microsoft Academic Search

    Edwin L. Fasanella; Walter Gordy

    1969-01-01

    Single crystals of L-phenylalanine-HCl have been observed with electron spin resonance after irradiation with a cobalt 60 gamma -ray source. The predominant signals observed are from long-lived benzyl radicals. The results indicate that one form of radiation damage to proteins containing this amino acid is breakage of the carbon-carbon bond to release the benzyl radical from the polypeptide chain. Hyperfine

  3. Electron Spin Resonance Study of ?-Irradiated Single Crystals of Semicarbazide Hydrochloride

    Microsoft Academic Search

    Keshav N. Shrivastava; Roy S. Anderson

    1968-01-01

    Electron spin resonance studies of ?-irradiated single crystals of semicarbazide hydrochloride and the deuterated form, ND2CONHND3+·Cl?, revealed the presence of the stably trapped ·N(?)H(?) ? N(?)H(?)3+ radical obtained by C&sngbnd;N bond rupture of the parent molecule. The principal g values were gaa = 2.0041 ± 0.0003, gbb = 2.0023, and gcc = 2.0044. The principal elements of the hyperfine couplings

  4. Morphologic Parameters of Normal Swallowing Events Using Single-Shot Fast Spin Echo Dynamic MRI

    Microsoft Academic Search

    Dana M. Hartl; Marcella Albiter; Frédéric Kolb; Bernard Luboinski; Robert Sigal

    2003-01-01

    This study was designed to determine visible and measurable morphological parameters in normal swallowing using dynamic MRI with single-shot fast spin echo (SSFSE), as a preliminary study in view of noninvasive MRI swallowing evaluation in patients with dysphagia. Seven healthy volunteers aged 24–40 underwent dynamic MRI with SSFSE, with a 1.5-T unit, using a head and neck antenna. Patients repeated

  5. Anisotropy of the low temperature resistivity of hexagonal single crystalline spin glass systems

    Microsoft Academic Search

    H. Albrecht; H. Meierling; E. F. Wassermann; H. Zähres; F. T. Hedgcock

    1982-01-01

    The impurity contribution to the resistivity in zero field (T) of dilute hexagonal single crystals of ZnMn, CdMn and MgMn has been studied in the mK range on samples cut parallel () and perpendicular () to thec-axis, using a SQUID technique for the measurements. Typical spin glass behavior is found in (T) as well as (T) for all alloys, with

  6. Spin Filtering and Entanglement Swapping through Coherent Evolution of a Single Quantum Dot

    Microsoft Academic Search

    Jose Garcia Coello; Abolfazl Bayat; Sougato Bose; John H. Jefferson; Charles E. Creffield

    2010-01-01

    We exploit the nondissipative dynamics of a pair of electrons in a large square quantum dot to perform singlet-triplet spin measurement through a single charge detection and show how this may be used for entanglement swapping and teleportation. The method is also used to generate the Affleck-Kennedy-Lieb-Tasaki ground state, a further resource for quantum computation. We justify, and derive analytic

  7. Spin Filtering and Entanglement Swapping through Coherent Evolution of a Single Quantum Dot

    Microsoft Academic Search

    Jose Garcia Coello; Abolfazl Bayat; Sougato Bose; John H. Jefferson; Charles E. Creffield

    2010-01-01

    We exploit the non-dissipative dynamics of a pair of electrons in a large\\u000asquare quantum dot to perform singlet-triplet spin measurement through a single\\u000acharge detection and show how this may be used for entanglement swapping and\\u000ateleportation. The method is also used to generate the AKLT ground state, a\\u000afurther resource for quantum computation. We justify, and derive analytic

  8. Electrical control of a long-lived spin qubit in a Si/SiGe quantum dot.

    PubMed

    Kawakami, E; Scarlino, P; Ward, D R; Braakman, F R; Savage, D E; Lagally, M G; Friesen, Mark; Coppersmith, S N; Eriksson, M A; Vandersypen, L M K

    2014-09-01

    Nanofabricated quantum bits permit large-scale integration but usually suffer from short coherence times due to interactions with their solid-state environment. The outstanding challenge is to engineer the environment so that it minimally affects the qubit, but still allows qubit control and scalability. Here, we demonstrate a long-lived single-electron spin qubit in a Si/SiGe quantum dot with all-electrical two-axis control. The spin is driven by resonant microwave electric fields in a transverse magnetic field gradient from a local micromagnet, and the spin state is read out in the single-shot mode. Electron spin resonance occurs at two closely spaced frequencies, which we attribute to two valley states. Thanks to the weak hyperfine coupling in silicon, a Ramsey decay timescale of 1??s is observed, almost two orders of magnitude longer than the intrinsic timescales in GaAs quantum dots, whereas gate operation times are comparable to those reported in GaAs. The spin echo decay time is ~40??s, both with one and four echo pulses, possibly limited by intervalley scattering. These advances strongly improve the prospects for quantum information processing based on quantum dots. PMID:25108810

  9. Non-Markovian dynamics of a single-mode cavity strongly coupled to an inhomogeneously broadened spin ensemble

    E-print Network

    Dmitry O. Krimer; Stefan Putz; Johannes Majer; Stefan Rotter

    2014-10-02

    We study the dynamics of a spin ensemble strongly coupled to a single-mode resonator driven by external pulses. When the mean frequency of the spin ensemble is in resonance with the cavity mode, damped Rabi oscillations are found between the spin ensemble and the cavity mode which we describe very accurately, including the dephasing effect of the inhomogeneous spin broadening. We demonstrate that a precise knowledge of this broadening is crucial both for a qualitative and a quantitative understanding of the temporal spin-cavity dynamics. On this basis we show that coherent oscillations between the spin ensemble and the cavity can be enhanced by a few orders of magnitude, when driving the system with pulses that match special resonance conditions. Our theoretical approach is tested successfully with an experiment based on an ensemble of negatively charged nitrogen-vacancy (NV) centers in diamond strongly coupled to a superconducting coplanar single-mode waveguide resonator.

  10. Non-Markovian dynamics of a single-mode cavity strongly coupled to an inhomogeneously broadened spin ensemble

    NASA Astrophysics Data System (ADS)

    Krimer, Dmitry O.; Putz, Stefan; Majer, Johannes; Rotter, Stefan

    2014-10-01

    We study the dynamics of a spin ensemble strongly coupled to a single-mode resonator driven by external pulses. When the mean frequency of the spin ensemble is in resonance with the cavity mode, damped Rabi oscillations are found between the spin ensemble and the cavity mode which we describe very accurately, including the dephasing effect of the inhomogeneous spin broadening. We demonstrate that a precise knowledge of this broadening is crucial both for a qualitative and a quantitative understanding of the temporal spin-cavity dynamics. On this basis we show that coherent oscillations between the spin ensemble and the cavity can be enhanced by a few orders of magnitude, when driving the system with pulses that match special resonance conditions. Our theoretical approach is tested successfully with an experiment based on an ensemble of negatively charged nitrogen-vacancy centers in diamond strongly coupled to a superconducting coplanar single-mode waveguide resonator.

  11. Accelerated 2D magnetic resonance spectroscopy of single spins using matrix completion

    E-print Network

    Jochen Scheuer; Alexander Stark; Matthias Kost; Martin B. Plenio; Boris Naydenov; Fedor Jelezko

    2015-07-14

    Two dimensional nuclear magnetic resonance (NMR) spectroscopy is one of the major tools for analysing the chemical structure of organic molecules and proteins. Despite its power, this technique requires long measurement times, which, particularly in the recently emerging diamond based single molecule NMR, limits its application to stable samples. Here we demonstrate a method which allows to obtain the spectrum by collecting only a small fraction of the experimental data. Our method is based on matrix completion which can recover the full spectral information from randomly sampled data points. We confirm experimentally the applicability of this technique by performing two dimensional electron spin echo envelope modulation (ESEEM) experiments on a two spin system consisting of a single nitrogen vacancy (NV) centre in diamond coupled to a single 13C nuclear spin. We show that the main peaks in the spectrum can be obtained with only 10 % of the total number of the data points. We believe that our results reported here can find an application in all types of two dimensional spectroscopy, as long as the measured matrices have a low rank.

  12. Elliptic functions and efficient control of Ising spin chains with unequal couplings

    E-print Network

    H. Yuan; R. Zeier; N. Khaneja

    2007-09-29

    In this article, we study optimal control of dynamics in a linear chain of three spin 1/2, weakly coupled with unequal Ising couplings. We address the problem of time-optimal synthesis of multiple spin quantum coherences. We derive time-optimal pulse sequence for creating a desired spin order by computing geodesics on a sphere under a special metric. The solution to the geodesic equation is related to the nonlinear oscillator equation and the minimum time to create multiple spin order can be expressed in terms of an elliptic integral. These techniques are used for efficient creation of multiple spin coherences in Ising spin-chains with unequal couplings.

  13. Addressing a single spin in diamond with a macroscopic dielectric microwave cavity

    SciTech Connect

    Le Floch, J.-M.; Tobar, M. E. [ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, The University of Western Australia, Crawley, Western Australia 6009 (Australia); Bradac, C.; Nand, N.; Volz, T. [ARC Centre of Excellence for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, North Ryde, New South Wales 2109 (Australia); Castelletto, S. [School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne (Australia)

    2014-09-29

    We present a technique for addressing single nitrogen-vacancy (NV) center spins in diamond over macroscopic distances using a tunable dielectric microwave cavity. We demonstrate optically detected magnetic resonance (ODMR) for a single negatively charged NV center (NV{sup –}) in a nanodiamond (ND) located directly under the macroscopic microwave cavity. By moving the cavity relative to the ND, we record the ODMR signal as a function of position, mapping out the distribution of the cavity magnetic field along one axis. In addition, we argue that our system could be used to determine the orientation of the NV{sup –} major axis in a straightforward manner.

  14. Wide-range control of ferromagnetic resonance by spin Hall effect V. E. Demidov,1,a)

    E-print Network

    Demokritov, S.O.

    as generation of spin waves for magnonic applications.7­9 In addition, the effect of STT on the dynamic magnetic of the ferromagnetic resonance (FMR) in a spin-Hall system con- sisting of a Permalloy (Py) micro-disk separated fromWide-range control of ferromagnetic resonance by spin Hall effect V. E. Demidov,1,a) S. Urazhdin,2

  15. Controlling orbital-selective Kondo effects in a single molecule through coordination chemistry.

    PubMed

    Tsukahara, Noriyuki; Minamitani, Emi; Kim, Yousoo; Kawai, Maki; Takagi, Noriaki

    2014-08-01

    Iron(II) phthalocyanine (FePc) molecule causes novel Kondo effects derived from the unique electronic structure of multi-spins and multi-orbitals when attached to Au(111). Two unpaired electrons in the d(z)(2) and the degenerate d? orbitals are screened stepwise, resulting in spin and spin+orbital Kondo effects, respectively. We investigated the impact on the Kondo effects of the coordination of CO and NO molecules to the Fe(2+) ion as chemical stimuli by using scanning tunneling microscopy (STM) and density functional theory calculations. The impacts of the two diatomic molecules are different from each other as a result of the different electronic configurations. The coordination of CO converts the spin state from triplet to singlet, and then the Kondo effects completely disappear. In contrast, an unpaired electron survives in the molecular orbital composed of Fe d(z)(2) and NO 5? and 2?* orbitals for the coordination of NO, causing a sharp Kondo resonance. The isotropic magnetic response of the peak indicates the origin is the spin Kondo effect. The diatomic molecules attached to the Fe(2+) ion were easily detached by applying a pulsed voltage at the STM junction. These results demonstrate that the single molecule chemistry enables us to switch and control the spin and the many-body quantum states reversibly. PMID:25106595

  16. PHYSICAL REVIEW A 88, 063802 (2013) Generating entangled spin states for quantum metrology by single-photon detection

    E-print Network

    Vuletic, Vladan

    2013-01-01

    by single-photon detection Robert McConnell,1 Hao Zhang,1 Senka ´Cuk,1,2 Jiazhong Hu,1 Monika H. Schleier, entangled, non-Gaussian states of collective spin in large atomic ensembles by means of single-photon [25] which have been experimentally implemented for photon-pair and single-photon generation [26

  17. SingleSpin Asymmetries in SemiInclusive DeepInelastic Scattering on a TransverselyPolarized Hydrogen Target

    E-print Network

    Single­Spin Asymmetries in Semi­Inclusive Deep­Inelastic Scattering on a Transversely to this intrinsic rotation of the nu­ cleon. The investigation of the nucleon's spin structure is the main task#erence between such a deep inelastic scattering (DIS) event and an elastic scattering event in which the nucleon

  18. Single-Spin Asymmetries in Semi-Inclusive Deep-Inelastic Scattering on a Transversely-Polarized Hydrogen Target

    E-print Network

    Single-Spin Asymmetries in Semi-Inclusive Deep-Inelastic Scattering on a Transversely to this intrinsic rotation of the nu- cleon. The investigation of the nucleon's spin structure is the main task between such a deep inelastic scattering (DIS) event and an elastic scattering event in which the nucleon

  19. Single spin asymmetries of inclusive hadrons produced in electron scattering from a transversely polarized [superscript 3]He target

    E-print Network

    Allada, Kalyan C.

    We report the first measurement of target single spin asymmetries (A[subscript N]) in the inclusive hadron production reaction, e + [superscript 3]He[superscript ?] ? h + X, using a transversely polarized [superscript 3]He ...

  20. Parametric analysis of plastic strain and force distribution in single pass metal spinning

    NASA Astrophysics Data System (ADS)

    Choudhary, Shashank; Tejesh, Chiruvolu Mohan; Regalla, Srinivasa Prakash; Suresh, Kurra

    2013-12-01

    Metal spinning also known as spin forming is one of the sheet metal working processes by which an axis-symmetric part can be formed from a flat sheet metal blank. Parts are produced by pressing a blunt edged tool or roller on to the blank which in turn is mounted on a rotating mandrel. This paper discusses about the setting up a 3-D finite element simulation of single pass metal spinning in LS-Dyna. Four parameters were considered namely blank thickness, roller nose radius, feed ratio and mandrel speed and the variation in forces and plastic strain were analysed using the full-factorial design of experiments (DOE) method of simulation experiments. For some of these DOE runs, physical experiments on extra deep drawing (EDD) sheet metal were carried out using En31 tool on a lathe machine. Simulation results are able to predict the zone of unsafe thinning in the sheet and high forming forces that are hint to the necessity for less-expensive and semi-automated machine tools to help the household and small scale spinning workers widely prevalent in India.

  1. Large-gap quantum spin Hall insulator in single layer bismuth monobromide Bi4Br4.

    PubMed

    Zhou, Jin-Jian; Feng, Wanxiang; Liu, Cheng-Cheng; Guan, Shan; Yao, Yugui

    2014-08-13

    Quantum spin Hall (QSH) insulators have gapless topological edge states inside the bulk band gap, which can serve as dissipationless spin current channels. The major challenge currently is to find suitable materials for this topological state. Here, we predict a new large-gap QSH insulator with bulk direct band gap of ? 0.18 eV, in single-layer Bi4Br4, which could be exfoliated from its three-dimensional bulk material due to the weakly bonded layered structure. The band gap of single-layer Bi4Br4 is tunable via strain engineering, and the QSH phase is robust against external strain. Moreover, because this material consists of special one-dimensional molecular chain as its basic building block, the single layer Bi4Br4 could be torn to ribbons with clean and atomically sharp edges. These nanoribbons, which have single-Dirac-cone edge states crossing the bulk band gap, are ideal wires for dissipationless transport. Our work thus provides a new promising material for experimental studies and practical applications of the QSH effect. PMID:25058154

  2. Phonon induced spin relaxation times of single donors and donor clusters in silicon

    NASA Astrophysics Data System (ADS)

    Hsueh, Yuling; Buch, Holger; Hollenberg, Lloyd; Simmons, Michelle; Klimeck, Gerhard; Rahman, Rajib

    2014-03-01

    The phonon induced relaxation times (T1) of electron spins bound to single phosphorous (P) donors and P donor clusters in silicon is computed using the atomistic tight-binding method. The electron-phonon Hamiltonian is directly computed from the strain dependent tight-binding Hamiltonian, and the relaxation time is computed from Fermi's Golden Rule using the donor states and the electron-phonon Hamiltonian. The self-consistent Hartree method is used to compute the multi-electron wavefunctions in donor clusters. The method takes into account the full band structure of silicon including the spin-orbit interaction, and captures both valley repopulation and single valley g-factor shifts in a unified framework. The single donor relaxation rate varies proportionally to B5, and is of the order of seconds at B =2T, both in good agreement with experimental single donor data (A. Morello et. al., Nature 467, 687 (2010)). T1 calculations in donor clusters show variations for different electron numbers and donor numbers and locations. The computed T1 in a 4P:5e donor cluster match well with a scanning tunneling microscope patterned P donor cluster (H. Buch et. al., Nature Communications 4, 2017 (2013)).

  3. Charge and spin pumping effects in a single-dot Aharonov–Bohm ring with ferromagnetic leads

    Microsoft Academic Search

    Hui Pan; Huai-Zhe Xu; Rong Lü

    2010-01-01

    The pumping of electrons through a single-dot Aharonov–Bohm ring attached to ferromagnetic leads are investigated theoretically by using the nonequilibrium Green's function method. It is found that the charge and spin pumping effects at zero-bias voltage can be produced by an oscillating electric field applied to the quantum dot. The pumped charge and spin currents through the single-dot ring are

  4. Rotary balance data for a single-engine trainer design for an angle-of-attack range of 8 deg to 90 deg. [conducted in langely spin tunnel

    NASA Technical Reports Server (NTRS)

    Pantason, P.; Dickens, W.

    1979-01-01

    Aerodynamic characteristics obtained in a rotational flow environment utilizing a rotary balance located in the Langley spin tunnel are presented in plotted form for a 1/6 scale, single engine trainer airplane model. The configurations tested included the basic airplane, various wing leading edge devices, elevator, aileron and rudder control settings as well as airplane components. Data are presented without analysis for an angle of attack range of 8 to 90 degrees and clockwise and counter-clockwise rotations.

  5. Measurement of W+/- boson single-spin asymmetry in transversely polarized pp collisions at STAR

    NASA Astrophysics Data System (ADS)

    Smirnov, Dmitri; Fazio, Salvatore; STAR Collaboration

    2013-10-01

    TMeasurement of W+/- boson single-spin asymmetry in transversely polarized pp collisions at STARhe Sivers function f1T ? describes the correlation of parton transverse momentum with the transverse spin of the nucleon. There is evidence of a quark Sivers effect in semi-inclusive DIS (SIDIS) measurements. Important aspects of the Sivers effect include its process dependence and the color gauge invariance. As a consequence, the quark Sivers functions are of opposite sign in SIDIS and in Drell-Yan and this non-universality is a fundamental prediction from the gauge invariance of QCD. The experimental test of this sign change is one of the open questions in hadronic physics, and can provide a direct verification of QCD factorization. While luminosities required for a meaningful measurement of asymmetries in Drell-Yan production are challenging, W+/- production with a comparable sensitivity to the predicted sign change can be measured at the STAR experiment. At these large Q2 the result can also provide essential input for the evolution effects of the Sivers function. We report on the first attempt to measure the transverse single spin asymmetry, AN, of the W+/- boson at RHIC. The W kinematics is reconstructed by employing MC-based corrections dictated.

  6. Single-spin asymmetries in semi-inclusive deep inelastic scattering and Drell-Yan processes

    NASA Astrophysics Data System (ADS)

    Brodsky, Stanley J.; Hwang, Dae Sung; Kovchegov, Yuri V.; Schmidt, Ivan; Sievert, Matthew D.

    2013-07-01

    We examine in detail the diagrammatic mechanisms which provide the change of sign between the single transverse spin asymmetries measured in semi-inclusive deep inelastic scattering (SIDIS) and in the Drell-Yan process (DY). This asymmetry is known to arise due to the transverse spin dependence of the target proton combined with a T-odd complex phase. Using the discrete symmetry properties of transverse spinors, we show that the required complex phase originates in the denominators of rescattering diagrams and their respective cuts. For simplicity, we work in a model where the proton consists of a valence quark and a scalar diquark. We then show that the phases generated in SIDIS and in DY originate from distinctly different cuts in the amplitudes, which at first appears to obscure the relationship between the single-spin asymmetries in the two processes. Nevertheless, further analysis demonstrates that the contributions of these cuts are identical in the leading-twist Bjorken kinematics considered, resulting in the standard sign-flip relation between the Sivers functions in SIDIS and DY. Physically, this fundamental, but yet untested, prediction occurs because the Sivers effect in the Drell-Yan reaction is modified by the initial-state “lensing” interactions of the annihilating antiquark, in contrast to the final-state lensing which produces the Sivers effect in deep inelastic scattering.

  7. Coherent control of two nuclear spins using the anisotropic hyperfine interaction

    E-print Network

    Yingjie Zhang; Colm A. Ryan; Raymond Laflamme; Jonathan Baugh

    2011-09-02

    We demonstrate coherent control of two nuclear spins mediated by the magnetic resonance of a hyperfine-coupled electron spin. This control is used to create a double nuclear coherence in one of the two electron spin manifolds, starting from an initial thermal state, in direct analogy to the creation of an entangled (Bell) state from an initially pure unentangled state. We identify challenges and potential solutions to obtaining experimental gate fidelities useful for quantum information processing in this type of system.

  8. Gd-based single-ion magnets with tunable magnetic anisotropy: molecular design of spin qubits.

    PubMed

    Martínez-Pérez, M J; Cardona-Serra, S; Schlegel, C; Moro, F; Alonso, P J; Prima-García, H; Clemente-Juan, J M; Evangelisti, M; Gaita-Ariño, A; Sesé, J; van Slageren, J; Coronado, E; Luis, F

    2012-06-15

    We report ac susceptibility and continuous wave and pulsed EPR experiments performed on GdW10 and GdW30 polyoxometalate clusters, in which a Gd3+ ion is coordinated to different polyoxometalate moieties. Despite the isotropic character of gadolinium as a free ion, these molecules show slow magnetic relaxation at very low temperatures, characteristic of single molecule magnets. For T?200??mK, the spin-lattice relaxation becomes dominated by pure quantum tunneling events, with rates that agree quantitatively with those predicted by the Prokof'ev and Stamp model [Phys. Rev. Lett. 80, 5794 (1998)]. The sign of the magnetic anisotropy, the energy level splittings, and the tunneling rates strongly depend on the molecular structure. We argue that GdW30 molecules are also promising spin qubits with a coherence figure of merit Q(M)?50. PMID:23004325

  9. Spin-Filtering and Entanglement Swapping through Coherent Evolution of a Single Quantum Dot

    E-print Network

    Coello, Jose Garcia; Bose, Sougato; Jefferson, John H; Creffield, Charles E

    2010-01-01

    We exploit the non-dissipative dynamics of a pair of electrons in a large square quantum dot to perform singlet-triplet spin measurement through a single charge detection and show how this may be used for entanglement swapping and teleportation. The method is also used to generate the AKLT ground state, a further resource for quantum computation. We justify, and derive analytic results for, an effective charge-spin Hamiltonian which is valid over a wide range of parameters and agrees well with exact numerical results of a realistic effective-mass model. Our analysis also indicates that the method is robust to choice of dot-size and initialization errors, as well as decoherence introduced by the hyperfine interaction.

  10. Spin filtering and entanglement swapping through coherent evolution of a single quantum dot.

    PubMed

    Coello, Jose Garcia; Bayat, Abolfazl; Bose, Sougato; Jefferson, John H; Creffield, Charles E

    2010-08-20

    We exploit the nondissipative dynamics of a pair of electrons in a large square quantum dot to perform singlet-triplet spin measurement through a single charge detection and show how this may be used for entanglement swapping and teleportation. The method is also used to generate the Affleck-Kennedy-Lieb-Tasaki ground state, a further resource for quantum computation. We justify, and derive analytic results for, an effective charge-spin Hamiltonian which is valid over a wide range of parameters and agrees well with exact numerical results of a realistic effective-mass model. Our analysis also indicates that the method is robust to the choice of dot-size and initialization errors, as well as decoherence. PMID:20868084

  11. Spin Filtering and Entanglement Swapping through Coherent Evolution of a Single Quantum Dot

    E-print Network

    Jose Garcia Coello; Abolfazl Bayat; Sougato Bose; John H. Jefferson; Charles E. Creffield

    2010-08-18

    We exploit the non-dissipative dynamics of a pair of electrons in a large square quantum dot to perform singlet-triplet spin measurement through a single charge detection and show how this may be used for entanglement swapping and teleportation. The method is also used to generate the AKLT ground state, a further resource for quantum computation. We justify, and derive analytic results for, an effective charge-spin Hamiltonian which is valid over a wide range of parameters and agrees well with exact numerical results of a realistic effective-mass model. Our analysis also indicates that the method is robust to choice of dot-size and initialization errors, as well as decoherence introduced by the hyperfine interaction.

  12. Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons

    NASA Astrophysics Data System (ADS)

    Airapetian, A.; Akopov, N.; Akopov, Z.; Aschenauer, E. C.; Augustyniak, W.; Avakian, R.; Avetissian, A.; Avetisyan, E.; Belostotski, S.; Bianchi, N.; Blok, H. P.; Borissov, A.; Bowles, J.; Bryzgalov, V.; Burns, J.; Capiluppi, M.; Capitani, G. P.; Cisbani, E.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P. F.; Deconinck, W.; De Leo, R.; De Nardo, L.; De Sanctis, E.; Diefenthaler, M.; Di Nezza, P.; Düren, M.; Ehrenfried, M.; Elbakian, G.; Ellinghaus, F.; Fabbri, R.; Fantoni, A.; Felawka, L.; Frullani, S.; Gabbert, D.; Gapienko, G.; Gapienko, V.; Gavrilov, G.; Gharibyan, V.; Giordano, F.; Gliske, S.; Golembiovskaya, M.; Hadjidakis, C.; Hartig, M.; Hasch, D.; Hillenbrand, A.; Hoek, M.; Holler, Y.; Hristova, I.; Ivanilov, A.; Jackson, H. E.; Joosten, S.; Kaiser, R.; Karyan, G.; Keri, T.; Kinney, E.; Kisselev, A.; Korotkov, V.; Kozlov, V.; Kravchenko, P.; Krivokhijine, V. G.; Lagamba, L.; Lapikás, L.; Lehmann, I.; Lenisa, P.; López Ruiz, A.; Lorenzon, W.; Ma, B.-Q.; Mahon, D.; Makins, N. C. R.; Manaenkov, S. I.; Mao, Y.; Marianski, B.; Martínez de la Ossa, A.; Marukyan, H.; Miller, C. A.; Miyachi, Y.; Movsisyan, A.; Murray, M.; Mussgiller, A.; Nappi, E.; Naryshkin, Y.; Negodaev, M.; Nowak, W.-D.; Pappalardo, L. L.; Perez-Benito, R.; Petrosyan, A.; Raithel, M.; Reimer, P. E.; Reolon, A. R.; Riedl, C.; Rith, K.; Rosner, G.; Rostomyan, A.; Rubin, J.; Ryckbosch, D.; Salomatin, Y.; Sanftl, F.; Schäfer, A.; Schnell, G.; Seitz, B.; Shibata, T.-A.; Shutov, V.; Stancari, M.; Statera, M.; Steffens, E.; Steijger, J. J. M.; Stewart, J.; Stinzing, F.; Taroian, S.; Terkulov, A.; Truty, R.; Trzcinski, A.; Tytgat, M.; Van Haarlem, Y.; Van Hulse, C.; Veretennikov, D.; Vikhrov, V.; Vilardi, I.; Wang, S.; Yaschenko, S.; Ye, Z.; Yen, S.; Yu, W.; Zagrebelnyy, V.; Zeiler, D.; Zihlmann, B.; Zupranski, P.

    2014-01-01

    Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle ? about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum PT relative to the direction of the incident beam, and the Feynman variable xF. The sin ? amplitudes are positive for ?+ and K+, slightly negative for ?- and consistent with zero for K-, with particular PT but weak xF dependences. Especially large asymmetries are observed for two small subsamples of events, where also the scattered electron was recorded by the spectrometer.

  13. Coherent Spin Control at the Quantum Level in an Ensemble-Based Optical Memory

    NASA Astrophysics Data System (ADS)

    Jobez, Pierre; Laplane, Cyril; Timoney, Nuala; Gisin, Nicolas; Ferrier, Alban; Goldner, Philippe; Afzelius, Mikael

    2015-06-01

    Long-lived quantum memories are essential components of a long-standing goal of remote distribution of entanglement in quantum networks. These can be realized by storing the quantum states of light as single-spin excitations in atomic ensembles. However, spin states are often subjected to different dephasing processes that limit the storage time, which in principle could be overcome using spin-echo techniques. Theoretical studies suggest this to be challenging due to unavoidable spontaneous emission noise in ensemble-based quantum memories. Here, we demonstrate spin-echo manipulation of a mean spin excitation of 1 in a large solid-state ensemble, generated through storage of a weak optical pulse. After a storage time of about 1 ms we optically read-out the spin excitation with a high signal-to-noise ratio. Our results pave the way for long-duration optical quantum storage using spin-echo techniques for any ensemble-based memory.

  14. Flight investigation of the effects of an outboard wing-leading-edge modification on stall/spin characteristics of a low-wing, single-engine, T-tail light airplane

    NASA Technical Reports Server (NTRS)

    Stough, H. Paul, III; Dicarlo, Daniel J.; Patton, James M., Jr.

    1987-01-01

    Flight tests were performed to investigate the change in stall/spin characteristics due to the addition of an outboard wing-leading-edge modification to a four-place, low-wing, single-engine, T-tail, general aviation research airplane. Stalls and attempted spins were performed for various weights, center of gravity positions, power settings, flap deflections, and landing-gear positions. Both stall behavior and wind resistance were improved compared with the baseline airplane. The latter would readily spin for all combinations of power settings, flap deflections, and aileron inputs, but the modified airplane did not spin at idle power or with flaps extended. With maximum power and flaps retracted, the modified airplane did enter spins with abused loadings or for certain combinations of maneuver and control input. The modified airplane tended to spin at a higher angle of attack than the baseline airplane.

  15. Spin-tunnel investigation of the spinning characteristics of typical single-engine general aviation airplane designs. 2: Low-wing model A; tail parachute diameter and canopy distance for emergency spin recovery

    NASA Technical Reports Server (NTRS)

    Burk, S. M., Jr.; Bowman, J. S., Jr.; White, W. L.

    1977-01-01

    A spin tunnel study is reported on a scale model of a research airplane typical of low-wing, single-engine, light general aviation airplanes to determine the tail parachute diameter and canopy distance (riser length plus suspension-line length) required for energency spin recovery. Nine tail configurations were tested, resulting in a wide range of developed spin conditions, including steep spins and flat spins. The results indicate that the full-scale parachute diameter required for satisfactory recovery from the most critical conditions investigated is about 3.2 m and that the canopy distance, which was found to be critical for flat spins, should be between 4.6 and 6.1 m.

  16. Controlling the quantum state of a single photon emitted from a single polariton

    SciTech Connect

    Stanojevic, Jovica; Parigi, Valentina; Bimbard, Erwan; Tualle-Brouri, Rosa; Ourjoumtsev, Alexei; Grangier, Philippe [Laboratoire Charles Fabry, Institut d'Optique, CNRS, Universite Paris-Sud, Campus Polytechnique, RD 128, FR-91127 Palaiseau cedex (France)

    2011-11-15

    We investigate in detail the optimal conditions for a high fidelity transfer from a single-polariton state to a single-photon state and subsequent homodyne detection of the single photon. We assume that, using various possible techniques, the single polariton has initially been stored as a spin-wave grating in a cloud of cold atoms inside a low-finesse cavity. This state is then transferred to a single-photon optical pulse using an auxiliary beam. We optimize the retrieval efficiency and determine the mode of the local oscillator that maximizes the homodyne efficiency of such a photon. We find that both efficiencies can have values close to one in a large region of experimental parameters.

  17. Roll control of a novel single line play robot by controlling air pressure of ducted fans

    Microsoft Academic Search

    Yong Ki Shim; Min Su Ha; Seul Jung

    2012-01-01

    This paper presents novel design and control of a single-wheel mobile robot that can balance on the single rope by air power induced from ducted fans. A single-wheel mobile robot called the single line play robot (SLPR) is designed for balancing on the rope. SLPR has three directional actuators to move on the plane. A roll angle is controlled for

  18. Multi-Sensor Single-Actuator Control of HVAC Systems 

    E-print Network

    Lin, C.; Auslander, D.; Federspiel, C.

    2002-01-01

    It is common to control several rooms in a building with a single sensor in one of the rooms and a single actuator driving just one control element such as an air damper. New, low-cost, wireless sensor technology now offers the opportunity...

  19. Multi-Sensor Single-Actuator Control of HVAC Systems

    E-print Network

    Lin, C.; Auslander, D.; Federspiel, C.

    2002-01-01

    It is common to control several rooms in a building with a single sensor in one of the rooms and a single actuator driving just one control element such as an air damper. New, low-cost, wireless sensor technology now offers the opportunity...

  20. Spin transport enhancement by controlling the Ag growth in lateral spin valves

    NASA Astrophysics Data System (ADS)

    Isasa, Miren; Villamor, Estitxu; Fallarino, Lorenzo; Idigoras, Olatz; Suszka, Anna K.; Tollan, Christopher; Berger, Andreas; Hueso, Luis E.; Casanova, Fèlix

    2015-06-01

    The role of the growth conditions onto the spin transport properties of silver (Ag) have been studied by using lateral spin valve structures. By changing the deposition conditions of Ag from polycrystalline to epitaxial growth, we have observed a considerable enhancement of the spin diffusion length, from {?\\text{Ag}}=449+/- 30 to 823+/- 59 ?nm. This enhancement in the spin diffusion length is closely related to the grain size of the Ag channel, which is 19???±???6?nm for polycrystalline Ag and 41???±???4?nm for epitaxial Ag. This study shows that diminishing the grain boundary contribution to the spin relaxation mechanism is an effective way to improve the spin diffusion length in metallic nanostructures.

  1. Propeller swirl effect on single-engine general-aviation aircraft stall-spin tendencies

    NASA Technical Reports Server (NTRS)

    Katz, Joseph; Feistel, Terry W.

    1987-01-01

    An investigation is conducted of the effect of a single engine, untapered low wing general aviation aircraft propeller's swirl on the craft's stall pattern. The asymmetrical character of the propeller's swirl can trigger an early stall of one of the wings, aggravating the spin-entry condition. It is shown that the combination of this propeller-induced effect with adverse sideslip can result in large and abrupt changes in the rolling moment, in such conditions as uncoordinated low speed turning maneuvers where the pilot yaws the aircraft with wings level, rather than rolling it.

  2. Dual-channel lock-in magnetometer with a single spin in diamond

    E-print Network

    N. M. Nusran; M. V. Gurudev Dutt

    2014-07-02

    We present an experimental method to perform dual-channel lock-in magnetometry of time-dependent magnetic fields using a single spin associated with a nitrogen-vacancy (NV) color center in diamond. We incorporate multi-pulse quantum sensing sequences with phase estimation algorithms to achieve linearized field readout and constant, nearly decoherence-limited sensitivity over a wide dynamic range. Furthermore, we demonstrate unambiguous reconstruction of the amplitude and phase of the magnetic field. We show that our technique can be applied to measure random phase jumps in the magnetic field, as well as phase-sensitive readout of the frequency.

  3. Trigluon correlations and single transverse spin asymmetry in open charm production

    SciTech Connect

    Kang Zhongbo; Qiu Jianwei [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States)

    2009-08-04

    We study the single transverse-spin asymmetry for open charm production in the semiinclusive lepton-hadron deep inelastic scattering (SIDIS) and pp collision. Within collinear factorization approach, we find that the asymmetry is sensitive to the twist-3 trigluon correlation functions in the proton. With a simple model for the trigluon correlation functions, we estimate the asymmetry in SIDIS for both COMPASS and eRHIC kinematics, as well as in pp collision at RHIC energy. We discuss the possibilities of extracting the trigluon correlation functions in these experiments.

  4. Generating Entangled Spin States for Quantum Metrology by Single-Photon Detection

    E-print Network

    McConnell, Robert; ?uk, Senka; Hu, Jiazhong; Schleier-Smith, Monika H; Vuleti?, Vladan

    2013-01-01

    We propose and analyze a probabilistic but heralded scheme to generate pure, entangled, non-Gaussian states of collective spin in large atomic ensembles by means of single-photon detection. One photon announces the preparation of a Dicke state, while two or more photons announce Schr\\"odinger cat states. The method produces pure states even for finite photon detection efficiency and weak atom-photon coupling. The entanglement generation can be made quasi-deterministic by means of repeated trial and feedback, enabling metrology beyond the standard quantum limit.

  5. Generating entangled spin states for quantum metrology by single-photon detection

    NASA Astrophysics Data System (ADS)

    McConnell, Robert; Zhang, Hao; ?uk, Senka; Hu, Jiazhong; Schleier-Smith, Monika H.; Vuleti?, Vladan

    2013-12-01

    We propose and analyze a probabilistic but heralded scheme to generate pure, entangled, non-Gaussian states of collective spin in large atomic ensembles by means of single-photon detection. One photon announces the preparation of a Dicke state, while two or more photons announce Schrödinger cat states. The method produces pure states even for finite photon detection efficiency and weak atom-photon coupling. The entanglement generation can be made quasideterministic by means of repeated trial and feedback, enabling metrology beyond the standard quantum limit.

  6. Single-spin azimuthal asymmetry in exclusive electroproduction of ?+ mesons on transversely polarized protons

    NASA Astrophysics Data System (ADS)

    Airapetian, A.; Akopov, N.; Akopov, Z.; Aschenauer, E. C.; Augustyniak, W.; Avetissian, A.; Avetisyan, E.; Ball, B.; Belostotski, S.; Bianchi, N.; Blok, H. P.; Böttcher, H.; Bonomo, C.; Borissov, A.; Bryzgalov, V.; Burns, J.; Capiluppi, M.; Capitani, G. P.; Cisbani, E.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P. F.; Deconinck, W.; de Leo, R.; de Nardo, L.; de Sanctis, E.; Diefenthaler, M.; di Nezza, P.; Dreschler, J.; Düren, M.; Ehrenfried, M.; Elbakian, G.; Ellinghaus, F.; Fabbri, R.; Fantoni, A.; Felawka, L.; Frullani, S.; Gabbert, D.; Gapienko, V.; Garibaldi, F.; Gharibyan, V.; Giordano, F.; Gliske, S.; Hadjidakis, C.; Hartig, M.; Hasch, D.; Hill, G.; Hillenbrand, A.; Hoek, M.; Holler, Y.; Hristova, I.; Imazu, Y.; Ivanilov, A.; Jackson, H. E.; Jo, H. S.; Joosten, S.; Kaiser, R.; Keri, T.; Kinney, E.; Kisselev, A.; Kobayashi, N.; Korotkov, V.; Kravchenko, P.; Lagamba, L.; Lamb, R.; Lapikás, L.; Lehmann, I.; Lenisa, P.; Linden-Levy, L. A.; López Ruiz, A.; Lorenzon, W.; Lu, X.-G.; Lu, X.-R.; Ma, B.-Q.; Mahon, D.; Makins, N. C. R.; Manaenkov, S. I.; Manfré, L.; Mao, Y.; Marianski, B.; Martinez de La Ossa, B.; Marukyan, H.; Miller, C. A.; Miyachi, Y.; Movsisyan, A.; Muccifora, V.; Murray, M.; Mussgiller, A.; Nappi, E.; Naryshkin, Y.; Nass, A.; Nowak, W.-D.; Pappalardo, L. L.; Perez-Benito, R.; Reimer, P. E.; Reolon, A. R.; Riedl, C.; Rith, K.; Rosner, G.; Rostomyan, A.; Rubin, J.; Ryckbosch, D.; Salomatin, Y.; Sanftl, F.; Schäfer, A.; Schnell, G.; Schüler, K. P.; Seitz, B.; Shibata, T.-A.; Shutov, V.; Stancari, M.; Statera, M.; Steijger, J. J. M.; Stenzel, H.; Stewart, J.; Taroian, S.; Terkulov, A.; Trzcinski, A.; Tytgat, M.; Vandenbroucke, A.; van der Nat, P. B.; van Haarlem, Y.; van Hulse, C.; Varanda, M.; Veretennikov, D.; Vikhrov, V.; Vilardi, I.; Vogel, C.; Wang, S.; Yaschenko, S.; Ye, H.; Ye, Z.; Yen, S.; Yu, W.; Zeiler, D.; Zihlmann, B.; Zupranski, P.; HERMES Collaboration

    2010-01-01

    Exclusive electroproduction of ? mesons was studied by scattering 27.6 GeV positrons or electrons off a transversely polarized hydrogen target. The single-spin azimuthal asymmetry with respect to target polarization was measured as a function of the Mandelstam variable t, the Bjorken scaling variable xB, and the virtuality Q of the exchanged photon. The extracted Fourier components of the asymmetry were found to be consistent with zero, except one that was found to be large and that involves interference of contributions from longitudinal and transverse virtual photons.

  7. Generating Entangled Spin States for Quantum Metrology by Single-Photon Detection

    NASA Astrophysics Data System (ADS)

    McConnell, Robert; Zhang, Hao; Cuk, Senka; Hu, Jiazhong; Schleier-Smith, Monika; Vuletic, Vladan

    2014-05-01

    We present a proposal and latest experimental results on a probabilistic but heralded scheme to generate non-Gaussian entangled states of collective spin in large atomic ensembles by means of single-photon detection. One photon announces the preparation of a Dicke state, while two or more photons announce Schrödinger cat states. The entangled states thus produced allow interferometry below the Standard Quantum Limit (SQL). The method produces nearly pure states even for finite photon detection efficiency and weak atom-photon coupling. The entanglement generation can be made quasi-deterministic by means of repeated trial and feedback.

  8. Cytoplasmic Solvent Structure of Single Barnacle Muscle Cells Studied by Electron Spin Resonance

    PubMed Central

    Sachs, Fred; Latorre, Ramon

    1974-01-01

    A free radical probe was introduced into single barnacle muscle cells, and its freedom of motion inferred from the spin resonance spectra. The probe reported an average local viscosity of 5-10 cp compared with 1 cp for pure water. From a comparison of the temperature dependence of the probe's tumbling rate in model aqueous systems and in the muscle we concluded that in the muscle the probe was undergoing fast exchange between sites of different mobility. Thus 10 cp must be taken as an upper limit for the viscosity of most cell water. PMID:4364470

  9. Analytic derivative couplings for spin-flip configuration interaction singles and spin-flip time-dependent density functional theory.

    PubMed

    Zhang, Xing; Herbert, John M

    2014-08-14

    We revisit the calculation of analytic derivative couplings for configuration interaction singles (CIS), and derive and implement these couplings for its spin-flip variant for the first time. Our algorithm is closely related to the CIS analytic energy gradient algorithm and should be straightforward to implement in any quantum chemistry code that has CIS analytic energy gradients. The additional cost of evaluating the derivative couplings is small in comparison to the cost of evaluating the gradients for the two electronic states in question. Incorporation of an exchange-correlation term provides an ad hoc extension of this formalism to time-dependent density functional theory within the Tamm-Dancoff approximation, without the need to invoke quadratic response theory or evaluate third derivatives of the exchange-correlation functional. Application to several different conical intersections in ethylene demonstrates that minimum-energy crossing points along conical seams can be located at substantially reduced cost when analytic derivative couplings are employed, as compared to use of a branching-plane updating algorithm that does not require these couplings. Application to H3 near its D(3h) geometry demonstrates that correct topology is obtained in the vicinity of a conical intersection involving a degenerate ground state. PMID:25134548

  10. Spin-controlled superconductivity and tunable triplet correlations in graphene nanostructures.

    PubMed

    Halterman, Klaus; Valls, Oriol T; Alidoust, Mohammad

    2013-07-26

    We study graphene ferromagnet/superconductor/ferromagnet (F/S/F) nanostructures via a microscopic self-consistent Dirac Bogoliubov-de Gennes formalism. We show that as a result of proximity effects, experimentally accessible spin switching phenomena can occur as one tunes the Fermi level ?F of the F regions or varies the angle ? between exchange field orientations. Superconductivity can then be switched on and off by varying either ? or ?F (a spin-controlled superconducting graphene switch). The induced equal-spin triplet correlations in S can be controlled by tuning ?F, effectively making a graphene based two-dimensional spin-triplet valve. PMID:23931389

  11. Spin-Controlled Superconductivity and Tunable Triplet Correlations in Graphene Nanostructures

    NASA Astrophysics Data System (ADS)

    Halterman, Klaus; Valls, Oriol T.; Alidoust, Mohammad

    2013-07-01

    We study graphene ferromagnet/superconductor/ferromagnet (F/S/F) nanostructures via a microscopic self-consistent Dirac Bogoliubov-de Gennes formalism. We show that as a result of proximity effects, experimentally accessible spin switching phenomena can occur as one tunes the Fermi level ?F of the F regions or varies the angle ? between exchange field orientations. Superconductivity can then be switched on and off by varying either ? or ?F (a spin-controlled superconducting graphene switch). The induced equal-spin triplet correlations in S can be controlled by tuning ?F, effectively making a graphene based two-dimensional spin-triplet valve.

  12. Spin-wave storage using chirped control fields in atomic frequency comb-based quantum memory

    NASA Astrophysics Data System (ADS)

    Miná?, Ji?í; Sangouard, Nicolas; Afzelius, Mikael; de Riedmatten, Hugues; Gisin, Nicolas

    2010-10-01

    It has been shown that an inhomogeneously broadened optical transition shaped into an atomic frequency comb can store a large number of temporal modes of the electromagnetic field at the single-photon level without the need to increase the optical depth of the storage material. The readout of light modes is made efficient thanks to the rephasing of the optical-wavelength coherence similar to photon-echo-type techniques, and the reemission time is given by the comb structure. For on-demand readout and long storage times, two control fields are used to transfer the optical coherence back and forth into a spin wave. Here, we present a detailed analysis of the spin-wave storage based on chirped adiabatic control fields. In particular, we verify that chirped fields require significantly weaker intensities than ? pulses. The price to pay is a reduction of the multimode storage capacity that we quantify for realistic material parameters associated with solids doped with rare-earth-metal ions.

  13. Polytype control of spin qubits in silicon carbide

    PubMed Central

    Falk, Abram L.; Buckley, Bob B.; Calusine, Greg; Koehl, William F.; Dobrovitski, Viatcheslav V.; Politi, Alberto; Zorman, Christian A.; Feng, Philip X.-L.; Awschalom, David D.

    2013-01-01

    Crystal defects can confine isolated electronic spins and are promising candidates for solid-state quantum information. Alongside research focusing on nitrogen-vacancy centres in diamond, an alternative strategy seeks to identify new spin systems with an expanded set of technological capabilities, a materials-driven approach that could ultimately lead to ‘designer’ spins with tailored properties. Here we show that the 4H, 6H and 3C polytypes of SiC all host coherent and optically addressable defect spin states, including states in all three with room-temperature quantum coherence. The prevalence of this spin coherence shows that crystal polymorphism can be a degree of freedom for engineering spin qubits. Long spin coherence times allow us to use double electron–electron resonance to measure magnetic dipole interactions between spin ensembles in inequivalent lattice sites of the same crystal. Together with the distinct optical and spin transition energies of such inequivalent states, these interactions provide a route to dipole-coupled networks of separately addressable spins. PMID:23652007

  14. Polytype control of spin qubits in silicon carbide

    NASA Astrophysics Data System (ADS)

    Falk, Abram L.; Buckley, Bob B.; Calusine, Greg; Koehl, William F.; Dobrovitski, Viatcheslav V.; Politi, Alberto; Zorman, Christian A.; Feng, Philip X.-L.; Awschalom, David D.

    2013-05-01

    Crystal defects can confine isolated electronic spins and are promising candidates for solid-state quantum information. Alongside research focusing on nitrogen-vacancy centres in diamond, an alternative strategy seeks to identify new spin systems with an expanded set of technological capabilities, a materials-driven approach that could ultimately lead to ‘designer’ spins with tailored properties. Here we show that the 4H, 6H and 3C polytypes of SiC all host coherent and optically addressable defect spin states, including states in all three with room-temperature quantum coherence. The prevalence of this spin coherence shows that crystal polymorphism can be a degree of freedom for engineering spin qubits. Long spin coherence times allow us to use double electron-electron resonance to measure magnetic dipole interactions between spin ensembles in inequivalent lattice sites of the same crystal. Together with the distinct optical and spin transition energies of such inequivalent states, these interactions provide a route to dipole-coupled networks of separately addressable spins.

  15. Spin-Wave Spectrum in ``Single-Domain'' Magnetic Ground State of Triangular Lattice Antiferromagnet CuFeO2

    NASA Astrophysics Data System (ADS)

    Nakajima, Taro; Mitsuda, Setsuo; Haku, Tendai; Shibata, Kohei; Yoshitomi, Keisuke; Noda, Yukio; Aso, Naofumi; Uwatoko, Yoshiya; Terada, Noriki

    2011-01-01

    By means of neutron scattering measurements, we have investigated spin-wave excitation in a collinear four-sublattice (4SL) magnetic ground state of a triangular lattice antiferromagnet CuFeO2, which has been of recent interest as a strongly frustrated magnet, a spin--lattice coupled system and a multiferroic. To avoid mixing of spin-wave spectrum from magnetic domains having three different orientations reflecting trigonal symmetry of the crystal structure, we have applied uniaxial pressure on [1\\bar{1}0] direction of a single crystal CuFeO2. By elastic neutron scattering measurements, we have found that only 10 MPa of the uniaxial pressure results in almost ``single domain'' state in the 4SL phase. We have thus performed inelastic neutron scattering measurements using the single domain sample, and have identified two distinct spin-wave branches. The dispersion relation of the upper spin-wave branch cannot be explained by the previous theoretical model [R. S. Fishman: J. Appl. Phys. 103 (2008) 07B109]. This implies the importance of the lattice degree of freedom in the spin-wave excitation in this system, because the previous calculation neglected the effect of the spin-driven lattice distortion in the 4SL phase. We have also discussed relationship between the present results and the recently discovered ``electromagnon'' excitation.

  16. Stark shift control of single optical centers in diamond

    E-print Network

    Ph. Tamarat; T. Gaebel; J. R. Rabeau; M. Khan; A. D. Greentree; H. Wilson; L. C. L. Hollenberg; S. Prawer; P. Hemmer; F. Jelezko; J. Wrachtrup

    2006-07-25

    Lifetime limited optical excitation lines of single nitrogen vacancy (NV) defect centers in diamond have been observed at liquid helium temperature. They display unprecedented spectral stability over many seconds and excitation cycles. Spectral tuning of the spin selective optical resonances was performed via the application of an external electric field (i.e. the Stark shift). A rich variety of Stark shifts were observed including linear as well as quadratic components. The ability to tune the excitation lines of single NV centers has potential applications in quantum information processing.

  17. Universal quantum gates on electron-spin qubits with quantum dots inside single-side optical microcavities

    E-print Network

    Hai-Rui Wei; Fu-Guo Deng

    2015-03-01

    We present some compact quantum circuits for a deterministic quantum computing on electron-spin qubits assisted by quantum dots inside single-side optical microcavities, including the CNOT, Toffoli, and Fredkin gates. They are constructed by exploiting the giant optical Faraday rotation induced by a single-electron spin in a quantum dot inside a single-side optical microcavity as a result of cavity quantum electrodynamics. Our universal quantum gates have some advantages. First, all the gates are accomplished with a success probability of 100% in principle. Second, our schemes require no additional electron-spin qubits and they are achieved by some input-output processes of a single photon. Third, our circuits for these gates are simple and economic. Moreover, our devices for these gates work in both the weak coupling and the strong coupling regimes, and they are feasible in experiment.

  18. PHYSICS OF ELEMENTARY PARTICLES AND FIELDS: Single Transverse Spin Asymmetries at Parton Level

    NASA Astrophysics Data System (ADS)

    Cao, Hui-Geng; Ma, Jian-Ping; Sang, Hua-Zheng

    2010-02-01

    Two factorization approaches have been proposed for single transverse spin asymmetries. One is the collinear factorization, the other is the transverse-momentum-dependent factorization. They have been previously derived in a formal way by using diagram expansion at hadron level. If the two factorizations hold or can be proven, they should also hold when we replace hadrons with parton states. We examine these two factorizations at parton level with massless partons. It is nontrivial to generate these asymmetries at parton level with massless partons because the asymmetries require helicity-flip and nonzero absorptive parts in scattering amplitudes. By constructing suitable parton states with massless partons we derive the two factorizations for the asymmetry in Drell-Yan processes. It is found from our results that the collinear factorization derived at parton level is not the same as that derived at hadron level. Our results with massless partons confirm those derived with single massive parton state in our previous works.

  19. Symmetry-lowering lattice distortion at the spin reorientation in MnBi single crystals

    NASA Astrophysics Data System (ADS)

    McGuire, Michael A.; Cao, Huibo; Chakoumakos, Bryan C.; Sales, Brian C.

    2014-11-01

    Structural and physical properties determined by measurements on large single crystals of the anisotropic ferromagnet MnBi are reported. The findings support the importance of magnetoelastic effects in this material. X-ray diffraction reveals a structural phase transition at the spin reorientation temperature TS R=90 K. The distortion is driven by magnetoelastic coupling, and upon cooling transforms the structure from hexagonal to orthorhombic. Heat capacity measurements show a thermal anomaly at the crystallographic transition, which is suppressed rapidly by applied magnetic fields. Effects on the transport and anisotropic magnetic properties of the single crystals are also presented. Increasing anisotropy of the atomic displacement parameters for Bi with increasing temperature above TS R is revealed by neutron diffraction measurements. It is likely that this is directly related to the anisotropic thermal expansion in MnBi, which plays a key role in the spin reorientation and magnetocrystalline anisotropy. The identification of the true ground-state crystal structure reported here may be important for future experimental and theoretical studies of this permanent magnet material, which have to date been performed and interpreted using only the high-temperature structure.

  20. Single-spin asymmetries in W boson production at next-to-leading order

    NASA Astrophysics Data System (ADS)

    Ringer, Felix; Vogelsang, Werner

    2015-05-01

    We present an analytic next-to-leading-order QCD calculation of the partonic cross sections for single-inclusive lepton production in hadronic collisions, when the lepton originates from the decay of an intermediate electroweak boson and is produced at high transverse momentum. In particular, we consider the case of incoming longitudinally polarized protons for which parity-violating single-spin asymmetries arise that are exploited in the W boson program at RHIC to constrain the proton's helicity parton distributions. Our calculation enables a very fast and efficient numerical computation of the relevant spin asymmetries at RHIC, which is an important ingredient for the inclusion of RHIC data in a global analysis of nucleon helicity structure. We confirm the validity of our calculation by comparing it with an existing code that treats the next-to-leading-order cross sections entirely numerically by Monte Carlo integration techniques. We also provide new comparisons of the present RHIC data with results for some of the sets of polarized parton distributions available in the literature.

  1. Controlled transfer of single charge carriers

    SciTech Connect

    Urbina, C.; Pothier, H.; Lafarge, P.; Orfila, P.F.; Esteve, D.; Devoret, M. (SPSRM, Centre d'Etudes Nucleaires de Saclay, 91191 Gif-sur-Yvette (FR)); Geerlings, L.J.; Anderegg, V.F.; Holweg, P.A.M.; Nooij, J.E. (Dept. of Applied Physics, Delft Univ. of Technology, P.O. Box 5046, 2600 GA Delft (NL))

    1991-03-01

    This paper reports on the design and operation of two devices, the turnstile and the pump, that transfer electrons one by one. They are both based on the existence of stable electrostatic configurations in arrays of ultrasmall tunnel junctions. While the turnstile only works in the normal state the pump could in principle achieve the transfer of single Cooper pairs.

  2. Photon-spin controlled lasing oscillation in surface-emitting lasers

    NASA Astrophysics Data System (ADS)

    Ando, H.; Sogawa, T.; Gotoh, H.

    1998-08-01

    We report on photon-spin controlled lasing oscillation in GaAs surface-emitting lasers at room temperature. We demonstrate experimentally that the partial electron-spin alignment, created by optically pumping the GaAs laser active media with circularly polarized pulses, drastically changes the polarization state of the lasing output, causing circularly polarized lasing emission. We discuss the laser polarization characteristics in relation to the measured electron-spin relaxation time.

  3. Demonstration of Quantum Entanglement between a Single Electron Spin Confined to an InAs Quantum Dot and a Photon

    NASA Astrophysics Data System (ADS)

    Schaibley, J. R.; Burgers, A. P.; McCracken, G. A.; Duan, L.-M.; Berman, P. R.; Steel, D. G.; Bracker, A. S.; Gammon, D.; Sham, L. J.

    2013-04-01

    The electron spin state of a singly charged semiconductor quantum dot has been shown to form a suitable single qubit for quantum computing architectures with fast gate times. A key challenge in realizing a useful quantum dot quantum computing architecture lies in demonstrating the ability to scale the system to many qubits. In this Letter, we report an all optical experimental demonstration of quantum entanglement between a single electron spin confined to a single charged semiconductor quantum dot and the polarization state of a photon spontaneously emitted from the quantum dot’s excited state. We obtain a lower bound on the fidelity of entanglement of 0.59±0.04, which is 84% of the maximum achievable given the timing resolution of available single photon detectors. In future applications, such as measurement-based spin-spin entanglement which does not require sub-nanosecond timing resolution, we estimate that this system would enable near ideal performance. The inferred (usable) entanglement generation rate is 3×103s-1. This spin-photon entanglement is the first step to a scalable quantum dot quantum computing architecture relying on photon (flying) qubits to mediate entanglement between distant nodes of a quantum dot network.

  4. Measurement of Single- and Double-Spin Asymmetries in Deep Inelastic Pion Electroproduction with a Longitudinally Polarized Target

    NASA Astrophysics Data System (ADS)

    Avakian, H.; Bosted, P.; Burkert, V. D.; Elouadrhiri, L.; Adhikari, K. P.; Aghasyan, M.; Amaryan, M.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Branford, D.; Briscoe, W. J.; Brooks, W.; Carman, D. S.; Casey, L.; Cole, P. L.; Collins, P.; Crabb, D.; Crede, V.; D'Angelo, A.; Daniel, A.; Dashyan, N.; de Vita, R.; de Sanctis, E.; Deur, A.; Dey, B.; Dhamija, S.; Dickson, R.; Djalali, C.; Dodge, G.; Doughty, D.; Dupre, R.; El Alaoui, A.; Eugenio, P.; Fegan, S.; Fersch, R.; Forest, T. A.; Fradi, A.; Gabrielyan, M. Y.; Gavalian, G.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gohn, W.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Heddle, D.; Hicks, K.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Isupov, E. L.; Jawalkar, S. S.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, W.; Klein, A.; Klein, F. J.; Konczykowski, P.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Kuznetsov, V.; Livingston, K.; Lu, H. Y.; Markov, N.; Mayer, M.; Martinez, D.; McAndrew, J.; McCracken, M. E.; McKinnon, B.; Meyer, C. A.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrison, B.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niroula, M. R.; Osipenko, M.; Ostrovidov, A. I.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Anefalos Pereira, S.; Perrin, Y.; Pisano, S.; Pogorelko, O.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Ripani, M.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Salgado, C.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stepanyan, S.; Stoler, P.; Strauch, S.; Suleiman, R.; Taiuti, M.; Tedeschi, D. J.; Tkachenko, S.; Ungaro, M.; Vernarsky, B.; Vineyard, M. F.; Voutier, E.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zhang, J.; Zhao, B.; Zhao, Z. W.

    2010-12-01

    We report the first measurement of the transverse momentum dependence of double-spin asymmetries in semi-inclusive production of pions in deep-inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Jefferson Lab (JLab). Modulations of single spin asymmetries over the azimuthal angle between lepton scattering and hadron production planes ? have been measured over a wide kinematic range in Bjorken x and virtual photon squared four-momentum Q2. A significant nonzero sin?2? single spin asymmetry was observed for the first time indicating strong spin-orbit correlations for transversely polarized quarks in the longitudinally polarized proton.

  5. Measurement of Single- and Double-Spin Asymmetries in Deep Inelastic Pion Electroproduction with a Longitudinally Polarized Target

    SciTech Connect

    Avakian, H.; Bosted, P.; Burkert, V. D.; Elouadrhiri, L.; Brooks, W.; Carman, D. S.; Deur, A.; Guo, L.; Kubarovsky, V.; Nadel-Turonski, P.; Weygand, D. P. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Adhikari, K. P.; Amaryan, M.; Dodge, G.; Gavalian, G.; Guler, N.; Klein, A.; Kuhn, S. E.; Niroula, M. R.; Seraydaryan, H. [Old Dominion University, Norfolk, Virginia 23529 (United States)

    2010-12-31

    We report the first measurement of the transverse momentum dependence of double-spin asymmetries in semi-inclusive production of pions in deep-inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Jefferson Lab (JLab). Modulations of single spin asymmetries over the azimuthal angle between lepton scattering and hadron production planes {phi} have been measured over a wide kinematic range in Bjorken x and virtual photon squared four-momentum Q{sup 2}. A significant nonzero sin2{phi} single spin asymmetry was observed for the first time indicating strong spin-orbit correlations for transversely polarized quarks in the longitudinally polarized proton.

  6. Probing the effective nuclear-spin magnetic field in a single quantum dot via full counting statistics

    NASA Astrophysics Data System (ADS)

    Xue, Hai-Bin; Nie, Yi-Hang; Chen, Jingzhe; Ren, Wei

    2015-03-01

    We study theoretically the full counting statistics of electron transport through a quantum dot weakly coupled to two ferromagnetic leads, in which an effective nuclear-spin magnetic field originating from the configuration of nuclear spins is considered. We demonstrate that the quantum coherence between the two singly-occupied eigenstates and the spin polarization of two ferromagnetic leads play an important role in the formation of super-Poissonian noise. In particular, the orientation and magnitude of the effective field have a significant influence on the variations of the values of high-order cumulants, and the variations of the skewness and kurtosis values are more sensitive to the orientation and magnitude of the effective field than the shot noise. Thus, the high-order cumulants of transport current can be used to qualitatively extract information on the orientation and magnitude of the effective nuclear-spin magnetic field in a single quantum dot.

  7. Single spin asymmetry AN in polarized proton-proton elastic scattering at ?{s}=200 GeV

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alakhverdyants, A. V.; Alekseev, I.; Alford, J.; Anson, C. D.; Arkhipkin, D.; Aschenauer, E.; Averichev, G. S.; Balewski, J.; Banerjee, A.; Barnovska, Z.; Beavis, D. R.; Bellwied, R.; Betancourt, M. J.; Betts, R. R.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Brandin, A. V.; Brovko, S. G.; Bruna, E.; Bültmann, S.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Cai, X. Z.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chung, P.; Chwastowski, J.; Codrington, M. J. M.; Corliss, R.; Cramer, J. G.; Crawford, H. J.; Cui, X.; Das, S.; Davila Leyva, A.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derradi de Souza, R.; Dhamija, S.; Didenko, L.; Ding, F.; Dion, A.; Djawotho, P.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Elnimr, M.; Engelage, J.; Eppley, G.; Eun, L.; Evdokimov, O.; Fatemi, R.; Fazio, S.; Fedorisin, J.; Fersch, R. G.; Filip, P.; Finch, E.; Fisyak, Y.; Gagliardi, C. A.; Gangadharan, D. R.; Geurts, F.; Gibson, A.; Gliske, S.; Gorbunov, Y. N.; Grebenyuk, O. G.; Grosnick, D.; Gupta, S.; Guryn, W.; Haag, B.; Hajkova, O.; Hamed, A.; Han, L.-X.; Harris, J. W.; Hays-Wehle, J. P.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Huo, L.; Igo, G.; Jacobs, W. W.; Jena, C.; Judd, E. G.; Kabana, S.; Kang, K.; Kapitan, J.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kesich, A.; Kikola, D. P.; Kiryluk, J.; Kisel, I.; Kisiel, A.; Kizka, V.; Klein, S. R.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Koroleva, L.; Korsch, W.; Kotchenda, L.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Lamont, M. A. C.; Landgraf, J. M.; LaPointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Leight, W.; LeVine, M. J.; Li, C.; Li, L.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lima, L. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Lu, Y.; Luo, X.; Luszczak, A.; Ma, G. L.; Ma, Y. G.; Madagodagettige Don, D. M. M. D.; Mahapatra, D. P.; Majka, R.; Mall, O. I.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; McShane, T. S.; Mioduszewski, S.; Mitrovski, M. K.; Mohammed, Y.; Mohanty, B.; Mondal, M. M.; Morozov, B.; Munhoz, M. G.; Mustafa, M. K.; Naglis, M.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nogach, L. V.; Novak, J.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Oliveira, R. A. N.; Olson, D.; Ostrowski, P.; Pachr, M.; Page, B. S.; Pal, S. K.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Peryt, W.; Pile, P.; Planinic, M.; Pluta, J.; Plyku, D.; Poljak, N.; Porter, J.; Poskanzer, A. M.; Powell, C. B.; Pruneau, C.; Pruthi, N. K.; Przybycien, M.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Redwine, R.; Reed, R.; Riley, C. K.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ross, J. F.; Ruan, L.; Rusnak, J.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandacz, A.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, B.; Schmitz, N.; Schuster, T. R.; Seele, J.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shao, M.; Sharma, B.; Sharma, M.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Singaraju, R. N.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solanki, D.; Sorensen, P.; deSouza, U. G.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Steadman, S. G.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szanto de Toledo, A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarini, L. H.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M. S.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wada, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, Q.; Wang, X. L.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Whitten, C.; Wieman, H.; Wissink, S. W.; Witt, R.; Witzke, W.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, H.; Xu, N.; Xu, Q. H.; Xu, W.; Xu, Y.; Xu, Z.; Xue, L.; Yang, Y.; Yang, Y.; Yepes, P.; Yi, Y.; Yip, K.; Yoo, I.-K.

    2013-02-01

    We report a high precision measurement of the transverse single spin asymmetry AN at the center of mass energy ?{s}=200 GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The AN was measured in the four-momentum transfer squared t range 0.003?|t|?0.035 (, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of AN and its t-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this ?{s}, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.

  8. Single spin asymmetry AN in polarized proton-proton elastic scattering at s=200 GeV

    NASA Astrophysics Data System (ADS)

    STAR Collaboration; Adamczyk, L.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alakhverdyants, A. V.; Alekseev, I.; Alford, J.; Anson, C. D.; Arkhipkin, D.; Aschenauer, E.; Averichev, G. S.; Balewski, J.; Banerjee, A.; Barnovska, Z.; Beavis, D. R.; Bellwied, R.; Betancourt, M. J.; Betts, R. R.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Brandin, A. V.; Brovko, S. G.; Bruna, E.; Bültmann, S.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Cai, X. Z.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chung, P.; Chwastowski, J.; Codrington, M. J. M.; Corliss, R.; Cramer, J. G.; Crawford, H. J.; Cui, X.; Das, S.; Davila Leyva, A.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derradi de Souza, R.; Dhamija, S.; Didenko, L.; Ding, F.; Dion, A.; Djawotho, P.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Elnimr, M.; Engelage, J.; Eppley, G.; Eun, L.; Evdokimov, O.; Fatemi, R.; Fazio, S.; Fedorisin, J.; Fersch, R. G.; Filip, P.; Finch, E.; Fisyak, Y.; Gagliardi, C. A.; Gangadharan, D. R.; Geurts, F.; Gibson, A.; Gliske, S.; Gorbunov, Y. N.; Grebenyuk, O. G.; Grosnick, D.; Gupta, S.; Guryn, W.; Haag, B.; Hajkova, O.; Hamed, A.; Han, L.-X.; Harris, J. W.; Hays-Wehle, J. P.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Huo, L.; Igo, G.; Jacobs, W. W.; Jena, C.; Judd, E. G.; Kabana, S.; Kang, K.; Kapitan, J.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kesich, A.; Kikola, D. P.; Kiryluk, J.; Kisel, I.; Kisiel, A.; Kizka, V.; Klein, S. R.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Koroleva, L.; Korsch, W.; Kotchenda, L.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Lamont, M. A. C.; Landgraf, J. M.; LaPointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Leight, W.; LeVine, M. J.; Li, C.; Li, L.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lima, L. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Lu, Y.; Luo, X.; Luszczak, A.; Ma, G. L.; Ma, Y. G.; Madagodagettige Don, D. M. M. D.; Mahapatra, D. P.; Majka, R.; Mall, O. I.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; McShane, T. S.; Mioduszewski, S.; Mitrovski, M. K.; Mohammed, Y.; Mohanty, B.; Mondal, M. M.; Morozov, B.; Munhoz, M. G.; Mustafa, M. K.; Naglis, M.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nogach, L. V.; Novak, J.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Oliveira, R. A. N.; Olson, D.; Ostrowski, P.; Pachr, M.; Page, B. S.; Pal, S. K.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Peryt, W.; Pile, P.; Planinic, M.; Pluta, J.; Plyku, D.; Poljak, N.; Porter, J.; Poskanzer, A. M.; Powell, C. B.; Pruneau, C.; Pruthi, N. K.; Przybycien, M.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Redwine, R.; Reed, R.; Riley, C. K.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ross, J. F.; Ruan, L.; Rusnak, J.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandacz, A.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, B.; Schmitz, N.; Schuster, T. R.; Seele, J.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shao, M.; Sharma, B.; Sharma, M.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Singaraju, R. N.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solanki, D.; Sorensen, P.; deSouza, U. G.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Steadman, S. G.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szanto de Toledo, A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarini, L. H.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M. S.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wada, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, Q.; Wang, X. L.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Whitten, C.; Wieman, H.; Wissink, S. W.; Witt, R.; Witzke, W.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, H.; Xu, N.; Xu, Q. H.; Xu, W.; Xu, Y.; Xu, Z.; Xue, L.; Yang, Y.; Yang, Y.; Yepes, P.; Yi, Y.

    2013-02-01

    We report a high precision measurement of the transverse single spin asymmetry AN at the center of mass energy s=200 GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The AN was measured in the four-momentum transfer squared t range 0.003?|t|?0.035 (, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of AN and its t-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this s, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.

  9. Spin-phonon interactions to control the thermal transport in uranium dioxide

    NASA Astrophysics Data System (ADS)

    Gofryk, K.; Du, S.; Stanek, C. R.; Lashley, J. C.; Liu, X.-Y.; Schulze, R. K.; Smith, J. L.; Safarik, D. J.; Byler, D. D.; McClellan, K. J.; Uberuaga, B. P.; Scott, B. L.; Andersson, D. A.

    2015-03-01

    Despite more than sixty years of intense research of uranium dioxide, a thorough understanding is lacking for the microscopic processes that control its transport and thermodynamic properties. In particular, it is not clear how different degrees of freedom and quasiparticle excitations interact and what is the relationship to the thermal behavior. We report our new experimental and theoretical studies on oriented and well characterized single crystals of uranium dioxide. Our results indicate that strong spin-phonon coupling and resonant scattering are important for understanding the general thermal behavior, and also explains the observed anisotropy in thermal conductivity by coupling to the applied temperature gradient and breaking cubic symmetry. We will discuss implications of these results.

  10. Barrier-height and bias-voltage-controlled spin-filter effect and tunneling magnetoresistance in full ferromagnetic junctions

    Microsoft Academic Search

    Dafei Jin; Yuan Ren; Zheng-Zhong Li; Ming-Wen Xiao; Guojun Jin; An Hu

    2006-01-01

    Within the framework of the single electron spintronic model, we systematically studied the barrier-height and bias-voltage-controlled spin-filter effect and tunneling magnetoresistance (TMR) in ferromagnetic metal\\/ferromagnetic insulator\\/ferromagnetic metal (FM\\/FI\\/FM) tunnel junctions. We find that it is the extended quantum-coherence factor of Slonczewski, kappaL?2-kL?kL?, that physically controls the sign of the zero-bias TMR. This factor is a linear function of the mean

  11. Control of spin precession in a spin-injected field effect transistor.

    PubMed

    Koo, Hyun Cheol; Kwon, Jae Hyun; Eom, Jonghwa; Chang, Joonyeon; Han, Suk Hee; Johnson, Mark

    2009-09-18

    Spintronics increases the functionality of information processing while seeking to overcome some of the limitations of conventional electronics. The spin-injected field effect transistor, a lateral semiconducting channel with two ferromagnetic electrodes, lies at the foundation of spintronics research. We demonstrated a spin-injected field effect transistor in a high-mobility InAs heterostructure with empirically calibrated electrical injection and detection of ballistic spin-polarized electrons. We observed and fit to theory an oscillatory channel conductance as a function of monotonically increasing gate voltage. PMID:19762637

  12. Measurement of Single and Double-Spin Asymmetries in Deep Inelastic Pion Electroproduction with a Longitudinally Polarized Target

    Microsoft Academic Search

    H. Avakian; P. Bosted; V. D. Burkert; L. Elouadrhiri; K. P. Adhikari; M. Aghasyan; M. Amaryan; M. Anghinolfi; H. Baghdasaryan; J. Ball; M. Battaglieri; I. Bedlinskiy; A. S. Biselli; D. Branford; W. J. Briscoe; D. S. Carman; L. Casey; P. L. Cole; P. Collins; D. Crabb; V. Crede; A. D'Angelo; A. Daniel; N. Dashyan; R. de Vita; E. de Sanctis; A. Deur; B. Dey; S. Dhamija; R. Dickson; C. Djalali; G. Dodge; D. Doughty; R. Dupre; A. El Alaoui; P. Eugenio; S. Fegan; R. Fersch; T. A. Forest; A. Fradi; M. Y. Gabrielyan; G. Gavalian; N. Gevorgyan; G. P. Gilfoyle; K. L. Giovanetti; F. X. Girod; W. Gohn; R. W. Gothe; K. A. Griffioen; M. Guidal; N. Guler; L. Guo; K. Hafidi; H. Hakobyan; C. Hanretty; N. Hassall; D. Heddle; K. Hicks; M. Holtrop; Y. Ilieva; D. G. Ireland; E. L. Isupov; S. S. Jawalkar; K. Joo; D. Keller; M. Khandaker; P. Khetarpal; W. Kim; A. Klein; F. J. Klein; P. Konczykowski; V. Kubarovsky; S. E. Kuhn; S. V. Kuleshov; V. Kuznetsov; K. Livingston; H. Y. Lu; N. Markov; M. Mayer; D. Martinez; J. McAndrew; M. E. McCracken; B. McKinnon; C. A. Meyer; T. Mineeva; M. Mirazita; V. Mokeev; B. Moreno; K. Moriya; B. Morrison; H. Moutarde; E. Munevar; P. Nadel-Turonski; R. Nasseripour; S. Niccolai; G. Niculescu; I. Niculescu; M. R. Niroula; M. Osipenko; A. I. Ostrovidov; R. Paremuzyan; S. Pisano; E. Pasyuk; S. Anefalos Pereira; Y. Perrin; O. Pogorelko; J. W. Price; S. Procureur; Y. Prok; D. Protopopescu; B. A. Raue; G. Ricco; M. Ripani; G. Rosner; P. Rossi; F. Sabatié; M. S. Saini; J. Salamanca; C. Salgado; R. A. Schumacher; E. Seder; H. Seraydaryan; Y. G. Sharabian; D. I. Sober; D. Sokhan; S. S. Stepanyan; P. Stoler; S. Strauch; R. Suleiman; M. Taiuti; D. J. Tedeschi; S. Tkachenko; M. Ungaro; B. Vernarsky; M. F. Vineyard; E. Voutier; D. P. Watts; L. B. Weinstein; D. P. Weygand; M. H. Wood; J. Zhang; B. Zhao; Z. W. Zhao

    2010-01-01

    We report the first measurement of the transverse momentum dependence of double-spin asymmetries in semi-inclusive production of pions in deep-inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Jefferson Lab (JLab). Modulations of single spin asymmetries over the azimuthal angle between lepton scattering and

  13. Noise-compensating pulses for electrostatically controlled silicon spin qubits

    E-print Network

    Xin Wang; Fernando A. Calderon-Vargas; Muhed S. Rana; Jason P. Kestner; Edwin Barnes; Sankar Das Sarma

    2014-10-21

    We study the performance of SUPCODE---a family of dynamically correcting pulses designed to cancel simultaneously both Overhauser and charge noise for singlet-triplet spin qubits---adapted to silicon devices with electrostatic control. We consider both natural Si and isotope-enriched Si systems, and in each case we investigate the behavior of individual gates under static noise and perform randomized benchmarking to obtain the average gate error under realistic 1/f noise. We find that in most cases SUPCODE pulses offer roughly an order of magnitude reduction in gate error, and especially in the case of isotope-enriched Si, SUPCODE yields gate operations of very high fidelity. We also develop a version of SUPCODE that cancels the charge noise only, "$\\delta J$-SUPCODE", which is particularly beneficial for isotope-enriched Si devices where charge noise dominates Overhauser noise, offering a level of error reduction comparable to the original SUPCODE while yielding gate times that are 30% to 50% shorter. Our results show that the SUPCODE noise-compensating pulses provide a fast, simple, and effective approach to error suppression, bringing gate errors well below the quantum error correction threshold in principle.

  14. Electronic measurement and control of spin transport in silicon

    Microsoft Academic Search

    Ian Appelbaum; Biqin Huang; Douwe J. Monsma

    2007-01-01

    The spin lifetime and diffusion length of electrons are transport parameters that define the scale of coherence in spintronic devices and circuits. As these parameters are many orders of magnitude larger in semiconductors than in metals, semiconductors could be the most suitable for spintronics. So far, spin transport has only been measured in direct-bandgap semiconductors or in combination with magnetic

  15. Room-temperature implementation of the Deutsch-Jozsa algorithm with a single electronic spin in diamond

    E-print Network

    Fazhan Shi; Xing Rong; Nanyang Xu; Ya Wang; Jie Wu; Bo Chong; Xinhua Peng; Juliane Kniepert; Rolf-Simon Schoenfeld; Wolfgang Harneit; Mang Feng; Jiangfeng Du

    2010-02-12

    The nitrogen-vacancy defect center (NV center) is a promising candidate for quantum information processing due to the possibility of coherent manipulation of individual spins in the absence of the cryogenic requirement. We report a room-temperature implementation of the Deutsch-Jozsa algorithm by encoding both a qubit and an auxiliary state in the electron spin of a single NV center. By thus exploiting the specific S=1 character of the spin system, we demonstrate how even scarce quantum resources can be used for test-bed experiments on the way towards a large-scale quantum computing architecture.

  16. Control of single-photon transport in a one-dimensional waveguide by another single photon

    E-print Network

    Wei-Bin Yan; Heng Fan

    2014-08-10

    We study the controllable single-photon transport in a one-dimensional (1D) waveguide with nonlinear dispersion relation coupled to a three-level emitter in cascade configuration. An extra cavity field was introduced to drive one of the level transitions of the emitter. In the resonance case, when the extra cavity does not contain photons, the input single photon will be reflected, and when the cavity contains one photon, the full transmission of the input single photon can be obtained. In the off-resonance case, the single-photon transport can also be controlled by the parameters of the cavity. Therefore, we have shown that the single-photon transport can be controlled by an extra cavity field.

  17. Effects of the covalent linker groups on the spin transport properties of single nickelocene molecules attached to single-walled carbon nanotubes.

    PubMed

    Wei, Peng; Sun, Lili; Benassi, Enrico; Shen, Ziyong; Sanvito, Stefano; Hou, Shimin

    2012-05-21

    The understanding of how the spin moment of a magnetic molecule transfers to a carbon nanotube, when the molecule is attached to it, is crucial for designing novel supramolecular spin devices. Here we explore such an issue by modeling the spin transport of a single-walled carbon nanotube grafted with one nickelocene molecule. In particular we investigate how the electron transport becomes spin-polarized depending on the specific linking group bonding nickelocene to the nanotube. We consider as linkers both aziridine and pyrrolidine rings and the amide group. Our calculations show that, at variance with aziridine, both pyrrolidine and amide, do alter the sp(2) character of the binding site of the nanotube and thus affect the transmission around the Fermi level. However, only aziridine allows transferring the spin polarization of the nickelocene to the nanotube, whose conductance at the Fermi level becomes spin-polarized. This suggests the superiority of aziridine as a linker for grafting magnetic molecules onto carbon nanotubes with efficient spin filtering functionality. PMID:22612109

  18. Optical Control of Nuclear Spin Ensembles in Diamond

    NASA Astrophysics Data System (ADS)

    King, Jonathan; Reimer, Jeffrey

    2012-02-01

    We present new results on the hyperpolarization of ^13C nuclear spins in diamond through optically-oriented nitrogen vacancy (NV-) defects. Optical illumination of high NV- concentration diamonds at cryogenic temperatures and 9.4 Tesla results in a negative nuclear spin temperature with measured bulk-average polarization over 5%, although local polarization may be higher. The negative spin-temperature is attributed to a population inversion within the dipolar energy levels of the NV- spin ensemble. In our quantitative model, nuclei near defects equilibrate with the NV- dipolar energy reservoir and polarization is transported to the bulk material via spin diffusion. This model is tested by investigating a series of samples with varied defect density. We also investigate the nuclear hyperpolarization of NV- containing diamond nanocrystals. Such materials may be useful for surface transfer of polarization to target molecules for enhanced NMR sensitivity. Additionally, we investigate the dynamics and decoherence of the hyperpolarized nuclear spin ensemble and its interaction with electronic defect spins. Such phenomena are of fundamental interest to the use of diamond for quantum information applications.

  19. A single current sensor control technique for induction motors

    Microsoft Academic Search

    Chunpeng Zhang; Fei Lin

    2002-01-01

    This paper describes a single current sensor control technique for induction motors that uses only a single DC-link current sensing resistor to obtain the information of three line currents. The principal motivation is to reduce the cost, and improve the reliability of a drive system. However, in certain conditions, the measurement is distorted due to the too narrow current pulse

  20. Polarization control of single photon quantum orbital angular momentum

    E-print Network

    Roma "La Sapienza", Università di

    Polarization control of single photon quantum orbital angular momentum states E. Nagali1, F, Italy Abstract: The orbital angular momentum of photons, being defined in an infinite angular momentum of single photons and vice versa. All our schemes exploit a newly developed optical

  1. Dual gate control of bulk transport and magnetism in the spin-orbit insulator S r2Ir O4

    NASA Astrophysics Data System (ADS)

    Lu, Chengliang; Dong, Shuai; Quindeau, Andy; Preziosi, Daniele; Hu, Ni; Alexe, Marin

    2015-03-01

    The 5 d iridates have been the subject of much recent attention due to the predictions of a large array of novel electronic phases driven by twisting strong spin-orbit coupling and Hubbard correlation. As a prototype, the single-layered perovskite S r2Ir O4 was first revealed to host a Jeff=1 /2 Mott insulating state. In this material, the approximate energy scale of a variety of interactions, involving spin-orbit coupling, magnetic exchange interaction, and the Mott gap, allows close coupling among the corresponding physical excitations, opening the possibility of cross control of the physical properties. Here, we experimentally demonstrate the effective gate control of both the transport and magnetism in a S r2Ir O4 -based field effect transistor using an ionic liquid dielectric. This approach could go beyond the surface-limited field effect seen in conventional transistors, reflecting the unique aspect of the Jeff=1 /2 state. The simultaneous modulation of conduction and magnetism confirms the proposed intimate coupling of charge, orbital, and spin degrees of freedom in this oxide. These phenomena are probably related to an enhanced deviation from the ideal Jeff=1 /2 state due to the gate-promoted conduction. The present work would have important implications in modelling the unusual physics enabled by strong spin-orbit coupling and provides a new route to explore those emergent quantum phases in iridates.

  2. Control topology options for single-phase UPS inverters

    Microsoft Academic Search

    Michael J. Ryan; William E. Brumsickle; Robert D. Lorenz

    1997-01-01

    Four control topologies for single-phase uninterruptible power system (UPS) inverters are presented and compared, with the common objective of providing a dynamically stiff, low total harmonic distortion (THD), sinusoidal output voltage. Full-state feedback, full-state command controllers are shown, utilizing both filter inductor current and filter capacitor current feedback to augment output voltage control. All controllers presented include output voltage decoupling

  3. Adaptive Power Control for Single and Multiuser Opportunistic Systems 

    E-print Network

    Nam, Sung Sik

    2010-07-14

    ADAPTIVE POWER CONTROL FOR SINGLE AND MULTIUSER OPPORTUNISTIC SYSTEMS A Dissertation by SUNG SIK NAM Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR... OF PHILOSOPHY May 2009 Major Subject: Electrical Engineering ADAPTIVE POWER CONTROL FOR SINGLE AND MULTIUSER OPPORTUNISTIC SYSTEMS A Dissertation by SUNG SIK NAM Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...

  4. Conditional control of donor nuclear spins in silicon using stark shifts.

    PubMed

    Wolfowicz, Gary; Urdampilleta, Matias; Thewalt, Mike L W; Riemann, Helge; Abrosimov, Nikolai V; Becker, Peter; Pohl, Hans-Joachim; Morton, John J L

    2014-10-10

    Electric fields can be used to tune donor spins in silicon using the Stark shift, whereby the donor electron wave function is displaced by an electric field, modifying the hyperfine coupling between the electron spin and the donor nuclear spin. We present a technique based on dynamic decoupling of the electron spin to accurately determine the Stark shift, and illustrate this using antimony donors in isotopically purified silicon-28. We then demonstrate two different methods to use a dc electric field combined with an applied resonant radio-frequency (rf) field to conditionally control donor nuclear spins. The first method combines an electric-field induced conditional phase gate with standard rf pulses, and the second one simply detunes the spins off resonance. Finally, we consider different strategies to reduce the effect of electric field inhomogeneities and obtain above 90% process fidelities. PMID:25375741

  5. Conditional Control of Donor Nuclear Spins in Silicon Using Stark Shifts

    NASA Astrophysics Data System (ADS)

    Wolfowicz, Gary; Urdampilleta, Matias; Thewalt, Mike L. W.; Riemann, Helge; Abrosimov, Nikolai V.; Becker, Peter; Pohl, Hans-Joachim; Morton, John J. L.

    2014-10-01

    Electric fields can be used to tune donor spins in silicon using the Stark shift, whereby the donor electron wave function is displaced by an electric field, modifying the hyperfine coupling between the electron spin and the donor nuclear spin. We present a technique based on dynamic decoupling of the electron spin to accurately determine the Stark shift, and illustrate this using antimony donors in isotopically purified silicon-28. We then demonstrate two different methods to use a dc electric field combined with an applied resonant radio-frequency (rf) field to conditionally control donor nuclear spins. The first method combines an electric-field induced conditional phase gate with standard rf pulses, and the second one simply detunes the spins off resonance. Finally, we consider different strategies to reduce the effect of electric field inhomogeneities and obtain above 90% process fidelities.

  6. Electrically controlled spin wave transmission in ferromagnetic metal/insulator junctions

    NASA Astrophysics Data System (ADS)

    Sasaki, Yuta; Tatara, Gen

    2014-03-01

    We theoretically investigate spin wave transmission in ferromagnetic metal/ ferromagnetic insulator junctions under applied current. The current induces a Doppler shift of frequency[1] because the spin polarized current and spin wave are interacted with each other by the sd interaction. The energy and group velocity are modified by the current in ferromagnetic metal. First, we show that the negative refraction of spin wave is observed when the current is applied along the ferromagnetic metal/ ferromagnetic insulator interfaces. When the current is perpendicular to the interfaces, a diode effect is obtained. The transmittance depends on the incident direction of spin wave. To conclude, we demonstrate that spin wave transmission in this junction is electrically controllable.

  7. Fano effect upon tunneling of a spin-polarized electron through a single magnetic impurity

    NASA Astrophysics Data System (ADS)

    Val'kov, V. V.; Aksenov, S. V.; Ulanov, E. A.

    2013-01-01

    The calculations of transport characteristics of a single magnetic impurity showed that the presence of different effective channels for electron transmission results in the Fano effect. It was noticed that the external magnetic field and gate voltage allow controlling the conducting properties, which are governed by the configuration interaction between the states of the system.

  8. Controlling the Spins Angular Momentum in Ferromagnets with Sequences of Picosecond Acoustic Pulses

    PubMed Central

    Kim, Ji-Wan; Vomir, Mircea; Bigot, Jean-Yves

    2015-01-01

    Controlling the angular momentum of spins with very short external perturbations is a key issue in modern magnetism. For example it allows manipulating the magnetization for recording purposes or for inducing high frequency spin torque oscillations. Towards that purpose it is essential to modify and control the angular momentum of the magnetization which precesses around the resultant effective magnetic field. That can be achieved with very short external magnetic field pulses or using intrinsically coupled magnetic structures, resulting in a transfer of spin torque. Here we show that using picosecond acoustic pulses is a versatile and efficient way of controlling the spin angular momentum in ferromagnets. Two or three acoustic pulses, generated by femtosecond laser pulses, allow suppressing or enhancing the magnetic precession at any arbitrary time by precisely controlling the delays and amplitudes of the optical pulses. A formal analogy with a two dimensional pendulum allows us explaining the complex trajectory of the magnetic vector perturbed by the acoustic pulses. PMID:25687970

  9. Controlling the spins angular momentum in ferromagnets with sequences of picosecond acoustic pulses.

    PubMed

    Kim, Ji-Wan; Vomir, Mircea; Bigot, Jean-Yves

    2015-01-01

    Controlling the angular momentum of spins with very short external perturbations is a key issue in modern magnetism. For example it allows manipulating the magnetization for recording purposes or for inducing high frequency spin torque oscillations. Towards that purpose it is essential to modify and control the angular momentum of the magnetization which precesses around the resultant effective magnetic field. That can be achieved with very short external magnetic field pulses or using intrinsically coupled magnetic structures, resulting in a transfer of spin torque. Here we show that using picosecond acoustic pulses is a versatile and efficient way of controlling the spin angular momentum in ferromagnets. Two or three acoustic pulses, generated by femtosecond laser pulses, allow suppressing or enhancing the magnetic precession at any arbitrary time by precisely controlling the delays and amplitudes of the optical pulses. A formal analogy with a two dimensional pendulum allows us explaining the complex trajectory of the magnetic vector perturbed by the acoustic pulses. PMID:25687970

  10. Controlling the Spins Angular Momentum in Ferromagnets with Sequences of Picosecond Acoustic Pulses

    NASA Astrophysics Data System (ADS)

    Kim, Ji-Wan; Vomir, Mircea; Bigot, Jean-Yves

    2015-02-01

    Controlling the angular momentum of spins with very short external perturbations is a key issue in modern magnetism. For example it allows manipulating the magnetization for recording purposes or for inducing high frequency spin torque oscillations. Towards that purpose it is essential to modify and control the angular momentum of the magnetization which precesses around the resultant effective magnetic field. That can be achieved with very short external magnetic field pulses or using intrinsically coupled magnetic structures, resulting in a transfer of spin torque. Here we show that using picosecond acoustic pulses is a versatile and efficient way of controlling the spin angular momentum in ferromagnets. Two or three acoustic pulses, generated by femtosecond laser pulses, allow suppressing or enhancing the magnetic precession at any arbitrary time by precisely controlling the delays and amplitudes of the optical pulses. A formal analogy with a two dimensional pendulum allows us explaining the complex trajectory of the magnetic vector perturbed by the acoustic pulses.

  11. Single-spin asymmetries in the leptoproduction of transversely polarized ? hyperons

    DOE PAGESBeta

    Kanazawa, K.; Metz, A.; Pitonyak, D.; Schlegel, M.

    2015-05-01

    We analyze single-spin asymmetries (SSAs) in the leptoproduction of transversely polarized ? hyperons within the collinear twist-3 formalism. We calculate both the distribution and fragmentation terms in two different gauges (lightcone and Feynman) and show that the results are identical. This is the first time that the fragmentation piece has been analyzed for transversely polarized hadron production within the collinear twist-3 framework. In lightcone gauge we use the same techniques that were employed in computing the analogous piece in p? p ? ? X, which has become an important part to that reaction. With this in mind, we also verifymore »the gauge invariance of the formulas for the transverse SSA in the leptoproduction of pions. (author)« less

  12. Single-spin asymmetries in the leptoproduction of transversely polarized ? hyperons

    NASA Astrophysics Data System (ADS)

    Kanazawa, K.; Metz, A.; Pitonyak, D.; Schlegel, M.

    2015-05-01

    We analyze single-spin asymmetries (SSAs) in the leptoproduction of transversely polarized ? hyperons within the collinear twist-3 formalism. We calculate both the distribution and fragmentation terms in two different gauges (lightcone and Feynman) and show that the results are identical. This is the first time that the fragmentation piece has been analyzed for transversely polarized hadron production within the collinear twist-3 framework. In lightcone gauge we use the same techniques that were employed in computing the analogous piece in p? p ? ? X, which has become an important part to that reaction. With this in mind, we also verify the gauge invariance of the formulas for the transverse SSA in the leptoproduction of pions.

  13. Helicity asymmetry E measurement for single ?0 photoproduction with a frozen spin target

    NASA Astrophysics Data System (ADS)

    Iwamoto, Hideko; CLAS Collaboration

    2012-04-01

    The helicity asymmetry for single neutral pion photoproduction was measured using the CLAS detector in Hall B at the Thomas Jefferson National Accelerator Facility. This measurement used longitudinally polarized protons and circularly polarized photons with photon energis between 0.35 GeV to 2.4 GeV. The target was a frozen-spin butanol (C4H9OH) target, polarized at about 85%. The helicity asymmetry E for the ?p?p?0 was measured with missing-mass technique at the high statistics of about 12×106 events. The experimental results are compared to three available theoretical predictions, SAID, MAID, and EBAC. The preliminary results are in good agreement with the model calculations at low E? energy bins. However, a significant deviation is observed at high energy bins. Therefore, the new data will help to constrain the parameters of the theoretical models.

  14. The role of three-gluon correlation functions in the single spin asymmetry

    NASA Astrophysics Data System (ADS)

    Beppu, Hiroo; Kanazawa, Koichi; Koike, Yuji; Yoshida, Shinsuke

    2015-01-01

    We study the twist-3 three-gluon contribution to the single spin asymmetry in the light-hadron production in pp collision in the framework of the collinear factorization. We derive the corresponding cross section formula in the leading order with respect to the QCD coupling constant. We also present a numerical calculation of the asymmetry at the RHIC energy, using a model for the three-gluon correlation functions suggested by the asymmetry for the D-meson production at RHIC. We found that the asymmetries for the light-hadron and the jet productions are very useful to constrain the magnitude and form of the correlation functions. Since the three-gluon correlation functions shift the asymmetry for all kinds of hadrons in the same direction, it is unlikely that they become a main source of the asymmetry.

  15. Longitudinal-transverse double-spin asymmetries in single-inclusive leptoproduction of hadrons

    NASA Astrophysics Data System (ADS)

    Kanazawa, K.; Metz, A.; Pitonyak, D.; Schlegel, M.

    2015-03-01

    We analyze the longitudinal-transverse double-spin asymmetry in lepton-nucleon collisions where a single hadron is detected in the final state, i.e., ? ? N? ? h X. This is a subleading-twist observable in collinear factorization, and we look at twist-3 effects in both the transversely polarized nucleon and the unpolarized outgoing hadron. Results are anticipated for this asymmetry from both HERMES and Jefferson Lab Hall A, and it could be measured as well at COMPASS and a future Electron-Ion Collider. We also perform a numerical study of the distribution term, which, when compared to upcoming experimental results, could allow one to learn about the "worm-gear"-type function g ˜ (x) as well as assess the role of quark-gluon-quark correlations in the initial-state nucleon and twist-3 effects in the fragmenting unpolarized hadron.

  16. Single-spin asymmetries in the leptoproduction of transversely polarized ? hyperons

    DOE PAGESBeta

    Kanazawa, K. [Temple Univ., Philadelphia, PA (United States); Metz, A. [Temple Univ., Philadelphia, PA (United States); Pitonyak, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schlegel, M. [Tubingen Univ., Tubingen (Germany)

    2015-05-01

    We analyze single-spin asymmetries (SSAs) in the leptoproduction of transversely polarized ? hyperons within the collinear twist-3 formalism. We calculate both the distribution and fragmentation terms in two different gauges (lightcone and Feynman) and show that the results are identical. This is the first time that the fragmentation piece has been analyzed for transversely polarized hadron production within the collinear twist-3 framework. In lightcone gauge we use the same techniques that were employed in computing the analogous piece in p? p ? ? X, which has become an important part to that reaction. With this in mind, we also verify the gauge invariance of the formulas for the transverse SSA in the leptoproduction of pions. (author)

  17. Depression of the interlayer Josephson coupling in Bi2Sr2CaCu2O8x single crystals by spin-polarized

    E-print Network

    Lee, Hu-Jong

    Depression of the interlayer Josephson coupling in Bi2Sr2CaCu2O8þx single crystals by spin of Science and Technology, Pohang 790-784, South Korea Abstract We studied the effect of spin. Spin- injection through the Co electrode caused pair breaking in the CuO2 double layers, which led

  18. Local control of single atom magnetocrystalline anisotropy.

    PubMed

    Bryant, B; Spinelli, A; Wagenaar, J J T; Gerrits, M; Otte, A F

    2013-09-20

    Individual Fe atoms on a Cu(2)N/Cu(100) surface exhibit strong magnetic anisotropy due to the crystal field. We show that we can controllably enhance or reduce this anisotropy by adjusting the relative position of a second nearby Fe atom, with atomic precision, in a low-temperature scanning tunneling microscope. Local inelastic electron tunneling spectroscopy, combined with a qualitative first-principles model, reveal that the change in uniaxial anisotropy is driven by local strain due to the presence of the second Fe atom. PMID:24093296

  19. Controlled transport through a single molecule.

    PubMed

    Kumar, A; Heimbuch, R; Poelsema, B; Zandvliet, H J W

    2012-02-29

    We demonstrate how an electrode-molecule-electrode junction can be controllably opened and closed by careful tuning of the contacts' interspace and voltage. The molecule, an octanethiol, flips to bridge a ~1 nm interspace between substrate and scanning tunnelling microscope tip when an electric field exceeds a threshold (switch 'on'). Reducing the field below this threshold value leads to the reproducible detachment of the octanethiol (switch 'off'). Once contacted, a further reduction of the contacts' interspace leads to an increase of the conductance of the molecule. PMID:22311709

  20. Fast deterministic switching in orthogonal spin torque devices via the control of the relative spin polarizations

    SciTech Connect

    Park, Junbo; Buhrman, R. A. [Cornell University, Ithaca, New York 14853 (United States)] [Cornell University, Ithaca, New York 14853 (United States); Ralph, D. C. [Cornell University, Ithaca, New York 14853 (United States) [Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell, Ithaca, New York 14853 (United States)

    2013-12-16

    We model 100 ps pulse switching dynamics of orthogonal spin transfer (OST) devices that employ an out-of-plane polarizer and an in-plane polarizer. Simulation results indicate that increasing the spin polarization ratio, C{sub P}?=?P{sub IPP}/P{sub OPP}, results in deterministic switching of the free layer without over-rotation (360° rotation). By using spin torque asymmetry to realize an enhanced effective P{sub IPP}, we experimentally demonstrate this behavior in OST devices in parallel to anti-parallel switching. Modeling predicts that decreasing the effective demagnetization field can substantially reduce the minimum C{sub P} required to attain deterministic switching, while retaining low critical switching current, I{sub p}???500??A.

  1. Processing, spinning, and fabrication of continuous fibers of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Booker, Richard Delane

    Single-walled carbon nanotubes (SWNTs) show great promise for use in a wide range of applications. One of the most promising avenues for attaining these applications is the dispersion of SWNTs at high concentrations in superacids and processing into macroscopic articles such as fibers or films. Fibers spun from SWNT/superacid dispersions indicate that the morphology of the starting SWNT material influences the final morphology of the as-spun fiber. Here, we describe a method (termed disentanglement) of dispersing SWNTs in superacids and treating them using a high-shear, rotor/stator homogenizer, followed by coagulation to recover the solid SWNT material for use in fiber spinning. Several lines of experimental evidence (rheology and optical microscopy of the SWNTs in solution, scanning electron microscopy (SEM) of the coagulated material, and SEM of fibers spun from the coagulated material) show that this disentanglement treatment radically improves the degree of alignment in the SWNTs' morphology, which in turn improves the dispersibility and processability. Raman microscopy and thermogravimetric analysis (TGA) before and after homogenization show that the treatment does not damage the SWNTs. Although this technique is particularly important as a pre-processing step for fiber spinning of neat SWNT fibers, it is also useful for neat SWNT films, SWNT/polymer composites, and surfactant- or polymer-stabilized SWNT dispersions. Macroscopic neat SWNT fibers were successfully produced and characterized. Studies on coagulated fiber morphology suggest that slow acid removal is crucial to minimizing voids. Better SWNT coalescence and alignment were obtained by using appropriate coagulant and dope concentration. SWNTs were disentangled and dissolved at high concentrations (8 - 10 wt%) in 102% sulfuric acid. Fibers were subsequently extruded by dry-jet wet spinning into ice water and polyvinyl alcohol (PVA) / ice water. Drawing the fiber continuously while spinning further aligned the SWNTs within the fiber. The use of PVA (< 1%) in the coagulant slowed acid removal allowing better SWNT coalescence without damaging the SWNT electrical properties. The resulting combination of pre-processing and fiber drawing shows a threefold improvement in fiber tensile strength.

  2. Quantum control of orbital and spin dynamics in diamond using ultrafast optical pulses

    NASA Astrophysics Data System (ADS)

    Heremans, F. Joseph

    2015-03-01

    Optically addressable spin defects in solid-state materials have shown great potential for applications ranging from metrology to quantum information processing. Many of these experiments require a detailed understanding of the full Hamiltonian dynamics in order to develop precise quantum control. Here we use picosecond resonant optical pulses to investigate the coherent orbital and spin dynamics of the nitrogen-vacancy (NV) center in diamond, over timescales spanning six orders of magnitude. We implement an ultrafast optical pump-probe technique to study the NV center's orbital-doublet, spin-triplet excited state at cryogenic temperatures (T < 20 K), where the excited state becomes stable and optically coherent with the ground state. This technique, coupled with optical polarization selection rules, allows us to probe the coherent orbital dynamics of the NV center's excited state. These experiments reveal dynamics on femtosecond to nanosecond timescales due to the interplay between the ground and excited state orbital levels. This all-optical technique also provides a method to dynamically control the spin state of the NV center by harnessing the excited state structure. Through studying the spin dynamics of the NV center with coherent pulses of light, we are able to rotate the spin state on sub-nanosecond timescales. Furthermore, by tuning the excited-state spin Hamiltonian with an external magnetic field, we demonstrate arbitrary-axis spin rotations through controlled unitary evolution of the spin state. Extending this to the full excited-state manifold, we develop a time-domain quantum tomography technique to precisely map the NV center's excited state Hamiltonian. These techniques generalize to other systems and can be a powerful tool in characterizing and controlling qubits in other optically addressable spin systems. This work is supported by the AFOSR and NSF.

  3. Preparing Pseudo-Pure States in a Quadrupolar Spin System Using Optimal Control

    NASA Astrophysics Data System (ADS)

    Tan, Yi-Peng; Nie, Xin-Fang; Li, Jun; Chen, Hong-Wei; Zhou, Xian-Yi; Peng, Xin-Hua; Du, Jiang-Feng

    2012-12-01

    Pseudo-pure state (PPS) preparation is crucial in nuclear magnetic resonance quantum computation. There have been some methods in spin-1/2 systems and a few attempts in quadrupolar spin systems. As optimal control via gradient ascent pulses engineering (GRAPE) has been widely used in quantum information science, we apply this technique to PPS preparation in quadrupolar spin systems. This approach shows an effective and fast quantum control method for both the state preparation and the realization of quantum gates in quadrupolar systems.

  4. Singularity avoidance control laws for single gimbal control moment gyros

    Microsoft Academic Search

    D. E. Cornick

    1979-01-01

    Two singularity avoidance control laws are presented in this paper. These techniques are based upon the ability to calculate the exact instantaneous location of all singular gimbal angle sets. In the first control law, called the direct method, these gimbal angles are directly avoided by adding null-motion that is in a sense opposite to the relative distance vector between the

  5. Optical spin orientation of a single manganese atom in a semiconductor quantum dot using quasi-resonant excitation

    E-print Network

    Boyer, Edmond

    Optical spin orientation of a single manganese atom in a semiconductor quantum dot using quasi-resonant localized in a semiconductor quantum dot using quasi-resonant excitation at zero magnetic field. Optically the circular polarization of the excitation reflect the dynamics of this optical orientation mechanism

  6. Azimuthal single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarised hydrogen target

    E-print Network

    Markus Diefenthaler

    2006-12-06

    Azimuthal single-spin asymmetries (SSA) in semi-inclusive electroproduction of charged pions and kaons in deep-inelastic scattering of positrons on a transversely polarised hydrogen target were observed. SSA amplitudes for both the Collins and the Sivers mechanism are presented.

  7. Observation of Spin Exchange Between the Singly Ionized Xe+ Ground State and the Metastable State of Neutral Xenon

    Microsoft Academic Search

    Tetsuo Hadeishi; Chung-Heng Liu

    1966-01-01

    We have observed spin-exchange collisions between the singly ionized 2P32 ground state of Xe and the 3P2 metastable state of neutral Xe, both formed and aligned by electronic-impact excitation under space-charge neutralization. Extension to the rf spectroscopy of the ionized ground state of other noble-gas atoms seems promising.

  8. Multiferroic M-type hexaferrites with a room-temperature conical state and magnetically controllable spin helicity.

    PubMed

    Tokunaga, Y; Kaneko, Y; Okuyama, D; Ishiwata, S; Arima, T; Wakimoto, S; Kakurai, K; Taguchi, Y; Tokura, Y

    2010-12-17

    Magnetic and magnetoelectric (ME) properties have been studied for single crystals of Sc-doped M-type barium hexaferrites. Magnetization (M) and neutron diffraction measurements revealed that by tuning Sc concentration a longitudinal conical state is stabilized up to above room temperatures. ME measurements have shown that a transverse magnetic field (H) can induce electric polarization (P) at lower temperatures and that the spin helicity is nonvolatile and endurable up to near the conical magnetic transition temperature. It was also revealed that the response (reversal or retention) of the P vector upon the reversal of M varies with temperature. In turn, this feature allows us to control the relation between the spin helicity and the M vectors with H and temperature. PMID:21231619

  9. Observation of a single rare-earth ion in a crystal by electric-field modulation spectroscopy for a readout of a nuclear-spin qubit

    NASA Astrophysics Data System (ADS)

    Ichimura, Kouichi; Goto, Hayato; Nakamura, Satoshi; Kujiraoka, Mamiko

    2015-03-01

    Nuclear spin states of rare-earth-metal ions in a crystal are known as good candidates for qubits in solids because of their long coherence time and their good controllability by lights. In the frequency-domain quantum computer (FDQC), nuclear spin states of the ions are employed as qubits defined in a frequency domain, and interaction between the qubits is mediated by a single cavity mode. In FDQC we can use adiabatic passage with dark states to perform single-qubit gates and two-qubit gates, and a single-qubit gate using adiabatic passage has been demonstrated. For two-qubit gates, quantum states of qubit ions need to be read out and operated individually. In order to observe a single ion in a crystal, we studied modulated signals due to ions in a cavity-mode spectrum of a monolithic optical cavity made of Pr3+:Y2SiO5. Owing to the cavity enhancement and the electric-field modulation spectroscopy, signals which are likely due to individual ions (statistical fine structure in an inhomogeneously broadened optical trandition) were observed.

  10. Control system techniques for improved departure/spin resistance for fighter aircraft

    NASA Technical Reports Server (NTRS)

    Nguyen, L. T.

    1979-01-01

    Some fundamental information on control system effects on controllability of highly-maneuverable aircraft at high angles of attack and techniques for enhancing fighter aircraft departure/spin resistance using control system design is summarized. The discussion includes: (a) a brief review of pertinent high angle-of-attack phenomena including aerodynamics, inertia coupling, and kinematic coupling; (b) effects of conventional stability augmentation systems at high-alpha; (c) high-alpha control system concepts designed to enhance departure/spin resistance; and (d) the outlook for applications of these concepts to future fighters, particularly those designs which incorporate relaxed static stability.

  11. Controllable Josephson current through a pseudo-spin-valve structure

    Microsoft Academic Search

    C. Bell; G. Burnell; C. W. Leung; E. J. Tarte; D.-J. Kang; M. G. Blamire

    2003-01-01

    A thin Co\\/Cu\\/Permalloy (Ni$_{80}$Fe$_{20}$) pseudo-spin-valve structure is\\u000asandwiched between superconducting Nb contacts. When the current is passed\\u000aperpendicular to the plane of the film a Josephson critical current ($I_C$) is\\u000aobserved at 4.2 K, in addition to a magnetoresistance (MR) of $\\\\sim$ 0.5 % at\\u000ahigh bias. The hysteresis loop of the spin-valve structure can be cycled to\\u000amodulate the

  12. Optimal open-loop and feedback control of spacecraft using single gimbal control moment gyroscopes

    E-print Network

    Hoelscher, Brian Ray

    1992-01-01

    OPTIMAL OPEN-LOOP AND FEEDBACK CONTROL OF SPACECRAFT USING SINGLE GIMBAL CONTROL MOMENT GYROSCOPES A Thesis by Brian Ray Hoelscher Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December 1992 Major Subject: Aerospace Engineering OPTIMAL OPEN-LOOP AND FEEDBACK CONTROL OF SPACECRAFT USING SINGLE GIMBAL CONTROL MOMENT GYROSCOPES A Thesis by Brian Ray Hoelscher Approved as to style and content by...

  13. Robust control of entanglement in a Nitrogen-vacancy centre coupled to a Carbon-13 nuclear spin in diamond

    E-print Network

    R. S. Said; J. Twamley

    2009-03-23

    We address a problem of generating a robust entangling gate between electronic and nuclear spins in the system of a single nitrogen-vacany centre coupled to a nearest Carbon-13 atom in diamond against certain types of systematic errors such as pulse-length and off-resonance errors. We analyse the robustness of various control schemes: sequential pulses, composite pulses and numerically-optimised pulses. We find that numerically-optimised pulses, produced by the gradient ascent pulse engineering algorithm (GRAPE), are more robust than the composite pulses and the sequential pulses. The optimised pulses can also be implemented in a faster time than the composite pulses.

  14. Using Single Quantum States as Spin Filters to Study Spin Polarization in Ferromagnets Mandar M. Deshmukh and D. C. Ralph

    E-print Network

    Deshmukh, Mandar M.

    a ferromagnet and individual energy levels in an aluminum quantum dot, we show how spin-resolved quantum states by other techniques in larger devices having continuous densities of electronic states. By prob- ingK. Beyond a threshold voltage deter- mined by the charging energy, electron tunneling via individual quantum

  15. Optimal control of fast and high-fidelity quantum gates with electron and nuclear spins of a nitrogen-vacancy center in diamond

    NASA Astrophysics Data System (ADS)

    Chou, Yi; Huang, Shang-Yu; Goan, Hsi-Sheng

    2015-05-01

    A negatively charged nitrogen-vacancy (NV) center in diamond has been recognized as a good solid-state qubit. A system consisting of the electronic spin of the NV center and hyperfine-coupled nitrogen and additionally nearby carbon nuclear spins can form a quantum register of several qubits for quantum information processing or as a node in a quantum repeater. Several impressive experiments on the hybrid electron and nuclear spin register have been reported, but fidelities achieved so far are not yet at or below the thresholds required for fault-tolerant quantum computation (FTQC). Using quantum optimal control theory based on the Krotov method, we show here that fast and high-fidelity single-qubit and two-qubit gates in the universal quantum gate set for FTQC, taking into account the effects of the leakage state, nearby noise qubits, and distant bath spins, can be achieved with errors less than those required by the threshold theorem of FTQC.

  16. Quantum Dissipative Dynamics of the Magnetic Resonance Force Microscope in the Single-Spin Detection Limit

    E-print Network

    Bruder, Christoph

    -Spin Detection Limit Hanno Gassmann Department of Physics and Astronomy, University of Basel, Klingelbergstrasse cantilever motions. They solved numerically the time-dependent Schr¨odinger equation for the spin-pl

  17. On the design of single electron transistors for the measurement of spins in phosphorus doped silicon

    E-print Network

    Randeria, Mallika

    2012-01-01

    Phosphorus doped silicon is a prime candidate for spin based qubits. We plan to investigate a novel hybrid technique that combines the advantages of spin selective optical excitations with that of electrical readout ...

  18. Phase control of the spin-triplet state in S/F/S Josephson junctions

    NASA Astrophysics Data System (ADS)

    Gingrich, Eric C.

    For decades, the proximity effect in superconductor/ferromagnetic (S/F) hybrid systems was thought to be very short-ranged, with coherence lengths on the order of a nanometer. That changed in 2003 when Bergeret et al. suggested systems involving s-wave superconductors and ferromagnets with non-collinear magnetizations could generate spin-triplet supercurrent. This was a significant prediction that radically changed the outlook for these systems, with the possibility of bringing the ferromagnetic coherence length up to ranges similar to the normal metal coherence length. With the experimental confirmation of the spin-triplet state in S/F/S Josephson junctions in 2010, the flood-gates opened into a range of interesting studies. We have performed measurements on the magnetic and superconducting properties of the multilayer Ni/[Co/Ni]n. This arrangement of ferromagnetic materials, when grown with thicknesses of 0.4 nm Ni and 0.2 nm Co, demonstrate a magnetization that lies perpendicular to the plane of the films. Because it will, in the virgin state, possess a non-collinear magnetization with ferromagnets which have magnetizations that lie within the plane, it is a convenient multilayer for the generation of spin-triplet supercurrent. Our measurements of S/F'/F/F'/S Josephson junctions, where F' is a hard ferromagnet and F is the Co/Ni multilayer, confirmed the presence of the spin-triplet state, and demonstrated the viability of the Co/Ni multilayer as a triplet generating ferromagnet. We have also performed studies on the characteristics of a number of soft ferromagnetic alloys. These alloys are important for their potential as a soft ferromagnetic switching layer for application in our triplet control devices. To that end, we have created sputtering targets for four different ferromagnetic alloys: Molybdenum-doped Permalloy, Niobium-doped Permalloy, Copper-doped Permalloy, and Palladium Iron. These studies have included: atomic concentration measurements using EDS, magnetic measurements using a commercial MPMS measurement system and GMR, and superconducting studies done by fabricating S/F'/F/F''/S Josephson junctions with F'' the soft ferromagnet of interest. Lastly, we have performed measurements to study the relative phase of two S/F'/F/F''/S Josephson junctions patterned into a Superconducting Quantum Interference Device (SQUID). The phase of the junctions is determined by the relative rotation of the magnetizations through the junction. By applying an external field to the junctions, and utilizing shape anisotropy to control the switching fields, the F'' layer can be switched in a single junction. The switch in the state can be observed by measuring the interference in the current driven through the SQUID, which responds to the relative phase of the two junctions in the loop. These measurements have yielded promising early results for the prospect of controlling the spin-triplet state.

  19. Coherent spin control of a nanocavity-enhanced qubit in diamond

    DOE PAGESBeta

    Li, Luozhou; Lu, Ming; Schroder, Tim; Chen, Edward H.; Walsh, Michael; Bayn, Igal; Goldstein, Jordan; Gaathon, Ophir; Trusheim, Matthew E.; Mower, Jacob; et al

    2015-01-28

    A central aim of quantum information processing is the efficient entanglement of multiple stationary quantum memories via photons. Among solid-state systems, the nitrogen-vacancy centre in diamond has emerged as an excellent optically addressable memory with second-scale electron spin coherence times. Recently, quantum entanglement and teleportation have been shown between two nitrogen-vacancy memories, but scaling to larger networks requires more efficient spin-photon interfaces such as optical resonators. Here we report such nitrogen-vacancy nanocavity systems in strong Purcell regime with optical quality factors approaching 10,000 and electron spin coherence times exceeding 200 µs using a silicon hard-mask fabrication process. This spin-photon interfacemore »is integrated with on-chip microwave striplines for coherent spin control, providing an efficient quantum memory for quantum networks.« less

  20. Coherent spin control of a nanocavity-enhanced qubit in diamond

    E-print Network

    Luozhou Li; Tim Schröder; Edward H. Chen; Michael Walsh; Igal Bayn; Jordan Goldstein; Ophir Gaathon; Matthew E. Trusheim; Ming Lu; Jacob Mower; Mircea Cotlet; Matthew L. Markham; Daniel J. Twitchen; Dirk Englund

    2014-09-10

    A central aim of quantum information processing is the efficient entanglement of multiple stationary quantum memories via photons. Among solid-state systems, the nitrogen-vacancy (NV) centre in diamond has emerged as an excellent optically addressable memory with second-scale electron spin coherence times. Recently, quantum entanglement and teleportation have been shown between two NV-memories, but scaling to larger networks requires more efficient spin-photon interfaces such as optical resonators. Here, we demonstrate such NV-nanocavity systems with optical quality factors approaching 10,000 and electron spin coherence times exceeding 200 $\\mu$s using a silicon hard-mask fabrication process. This spin-photon interface is integrated with on-chip microwave striplines for coherent spin control, providing an efficient quantum memory for quantum networks.

  1. Coherent spin control of a nanocavity-enhanced qubit in diamond

    DOE PAGESBeta

    Li, Luozhou [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Lu, Ming [Brookhaven National Lab. (BNL), Upton, NY (United States); Schroder, Tim [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Chen, Edward H. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Walsh, Michael [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Bayn, Igal [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Goldstein, Jordan [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Gaathon, Ophir [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Trusheim, Matthew E. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Mower, Jacob [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Cotlet, Mircea [Brookhaven National Lab. (BNL), Upton, NY (United States); Markham, Matthew L. [Element Six, Santa Clara, CA (United States); Twitchen, Daniel J. [Element Six, Santa Clara, CA (United States); Englund, Dirk [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States)

    2015-01-28

    A central aim of quantum information processing is the efficient entanglement of multiple stationary quantum memories via photons. Among solid-state systems, the nitrogen-vacancy centre in diamond has emerged as an excellent optically addressable memory with second-scale electron spin coherence times. Recently, quantum entanglement and teleportation have been shown between two nitrogen-vacancy memories, but scaling to larger networks requires more efficient spin-photon interfaces such as optical resonators. Here we report such nitrogen-vacancy nanocavity systems in strong Purcell regime with optical quality factors approaching 10,000 and electron spin coherence times exceeding 200 µs using a silicon hard-mask fabrication process. This spin-photon interface is integrated with on-chip microwave striplines for coherent spin control, providing an efficient quantum memory for quantum networks.

  2. Spintronic single-qubit gate based on a quantum ring with spin-orbit interaction

    Microsoft Academic Search

    Péter Földi; Balázs Molnár; Mihaly G. Benedict; F. M. Peeters

    2005-01-01

    In a quantum ring connected with two external leads the spin properties of an\\u000aincoming electron are modified by the spin-orbit interaction resulting in a\\u000atransformation of the qubit state carried by the spin. The ring acts as a one\\u000aqubit spintronic quantum gate whose properties can be varied by tuning the\\u000aRashba parameter of the spin-orbit interaction, by changing

  3. Topographic control of non-axisymmetric stratified spin-up

    Microsoft Academic Search

    Sergey A. Smirnov; Don L. Boyer

    2007-01-01

    An experimental study was conducted to elucidate the influence of a sloping bottom boundary on global stratified spin-up. The system consisted of a rotating continuously stratified fluid confined in a domain which has a shape of an inverted round cone with the upper surface being free. It is shown that under similar flow conditions (the same absolute values of the

  4. Transverse Spin Structure of the Nucleon through Target Single Spin Asymmetry in Semi-Inclusive Deep-Inelastic $(e,e^\\prime \\pi^\\pm)$ Reaction at Jefferson Lab

    SciTech Connect

    Gao, H; Chen, J -P; Qian, X; Qiang, Y; Huang, M; Afanasev, A; Anselmino, M; Avakian, H; Cates, G; Chudakov, E; Cisbani, E; de Jager, C; Garibaldi, F; Hu, B T; Jiang, X; Kumar, K S; Li, X M; Lu, H J; Meziani, Z -E; Ma, B -Q; Mao, Y J; Peng, J -C; Prokudin, A; Schlegel, M; Souder, P; Xiao, Z G; Ye, Y

    2011-01-01

    Jefferson Lab (JLab) 12 GeV energy upgrade provides a golden opportunity to perform precision studies of the transverse spin and transverse-momentum-dependent structure in the valence quark region for both the proton and the neutron. In this paper, we focus our discussion on a recently approved experiment on the neutron as an example of the precision studies planned at JLab. The new experiment will perform precision measurements of target Single Spin Asymmetries (SSA) from semi-inclusive electro-production of charged pions from a 40-cm long transversely polarized $^3$He target in Deep-Inelastic-Scattering kinematics using 11 and 8.8 GeV electron beams. This new coincidence experiment in Hall A will employ a newly proposed solenoid spectrometer (SoLID). The large acceptance spectrometer and the high polarized luminosity will provide precise 4-D ($x$, $z$, $P_T$ and $Q^2$) data on the Collins, Sivers, and pretzelocity asymmetries for the neutron through the azimuthal angular dependence. The full 2$\\pi$ azimuthal angular coverage in the lab is essential in controlling the systematic uncertainties. The results from this experiment, when combined with the proton Collins asymmetry measurement and the Collins fragmentation function determined from the e$^+$e$^-$ collision data, will allow for a quark flavor separation in order to achieve a determination of the tensor charge of the d quark to a 10% accuracy. The extracted Sivers and pretzelocity asymmetries will provide important information to understand the correlations between the quark orbital angular momentum and the nucleon spin and between the quark spin and nucleon spin.

  5. Extracting W Single Spin Asymmetry in Longitudinally Polarized pp Collisions at PHENIX forward arms

    NASA Astrophysics Data System (ADS)

    Meles, Abraham

    2014-09-01

    The parity-violating longitudinal single spin asymmetry AL in the production of W bosons in p + p collisions at ?{ s} = 510 GeV is sensitive to the polarization of light quarks and anti-quarks in the proton. However, identifying the muons from the decay of the W is challenging due to a great background of hadronic processes and other muon producing processes. In the forward and backward hemispheres of PHENIX at RHIC, the muon spectrometers have been recently upgraded in order to provide additional trigger and tracking information to suppress those backgrounds. One of those upgrades is the Forward Vertex (FVTX) detector, a silicon-strip tracker. In 2013, PHENIX collected approximately 240 pb-1 of polarized p + p collisions at ?{ s} = 510 GeV with a beam polarization of 56 %. The ability of the FVTX to improve the W signal will be reviewed, over view of the analysis techniques used to extract the signal from the data in RHIC 2013 run will be discussed. The parity-violating longitudinal single spin asymmetry AL in the production of W bosons in p + p collisions at ?{ s} = 510 GeV is sensitive to the polarization of light quarks and anti-quarks in the proton. However, identifying the muons from the decay of the W is challenging due to a great background of hadronic processes and other muon producing processes. In the forward and backward hemispheres of PHENIX at RHIC, the muon spectrometers have been recently upgraded in order to provide additional trigger and tracking information to suppress those backgrounds. One of those upgrades is the Forward Vertex (FVTX) detector, a silicon-strip tracker. In 2013, PHENIX collected approximately 240 pb-1 of polarized p + p collisions at ?{ s} = 510 GeV with a beam polarization of 56 %. The ability of the FVTX to improve the W signal will be reviewed, over view of the analysis techniques used to extract the signal from the data in RHIC 2013 run will be discussed. Support from US Department of Energy.

  6. Voltage-controlled spin selection in a magnetic resonant tunneling diode.

    PubMed

    Slobodskyy, A; Gould, C; Slobodskyy, T; Becker, C R; Schmidt, G; Molenkamp, L W

    2003-06-20

    We have fabricated all II-VI semiconductor resonant tunneling diodes based on the (Zn,Mn,Be)Se material system, containing dilute magnetic material in the quantum well, and studied their current-voltage characteristics. When subjected to an external magnetic field the resulting spin splitting of the levels in the quantum well leads to a splitting of the transmission resonance into two separate peaks. This is interpreted as evidence of tunneling transport through spin polarized levels, and could be the first step towards a voltage controlled spin filter. PMID:12857209

  7. Control of light polarization using optically spin-injected vertical external cavity surface emitting lasers

    NASA Astrophysics Data System (ADS)

    Frougier, J.; Baili, G.; Alouini, M.; Sagnes, I.; Jaffrès, H.; Garnache, A.; Deranlot, C.; Dolfi, D.; George, J.-M.

    2013-12-01

    We fabricated and characterized an optically pumped (100)-oriented InGaAs/GaAsP multiple quantum well Vertical External Cavity Surface Emitting Laser (VECSEL). The structure is designed to allow the integration of a Metal-Tunnel-Junction ferromagnetic spin-injector for future electrical injection. We report here the control at room temperature of the electromagnetic field polarization using optical spin injection in the active medium of the VECSEL. The switching between two highly circular polarization states had been demonstrated using an M-shaped extended cavity in multi-modes lasing. This result witnesses an efficient spin-injection in the active medium of the LASER.

  8. Beam normal single spin asymmetry in forward angle inelastic electron-proton scattering using the q-weak apparatus

    NASA Astrophysics Data System (ADS)

    Nuruzzaman, FNU

    The Q-weak experiment in Hall-C at the Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton through the precision measurement of the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer. There is also a parity conserving Beam Normal Single Spin Asymmetry or transverse asymmetry (Bn) on H2 with a sin(phi)-like dependence due to two-photon exchange. If the size of elastic Bn is a few ppm, then a few percent residual transverse polarization in the beam, combined with small broken azimuthal symmetries in the detector, would require a few ppb correction to the Q-weak data. As part of a program of Bn background studies, we made the first measurement of Bn in the N-to-Delta(1232) transition using the Q-weak apparatus. The final transverse asymmetry, corrected for backgrounds and beam polarization, was found to be Bn = 42.82 +- 2.45 (stat) +- 16.07 (sys) ppm at beam energy Ebeam = 1.155 GeV, scattering angle theta = 8.3 degrees, and missing mass W = 1.2 GeV. Bn from electron-nucleon scattering is a unique tool to study the gamma*DeltaDelta form factors, and this measurement will help to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process. To help correct false asymmetries from beam noise, a beam modulation system was implemented to induce small position, angle, and energy changes at the target to characterize detector response to the beam jitter. Two air-core dipoles separated by ˜10 m were pulsed at a time to produce position and angle changes at the target, for virtually any tune of the beamline. The beam energy was modulated using an SRF cavity. The hardware and associated control instrumentation will be described in this dissertation. Preliminary detector sensitivities were extracted which helped to reduce the width of the measured asymmetry. The beam modulation system has also proven valuable for tracking changes in the beamline optics, such as dispersion at the target.

  9. Beam Normal Single Spin Asymmetry in Forward Angle Inelastic Electron-Proton Scattering using the Q-Weak Apparatus

    SciTech Connect

    Nuruzzaman, nfn [Thomas Jefferson National Accelerator Facility and Hampton University

    2014-12-01

    The Q-weak experiment in Hall-C at the Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton through the precision measurement of the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer. There is also a parity conserving Beam Normal Single Spin Asymmetry or transverse asymmetry (B_n) on H_2 with a sin(phi)-like dependence due to two-photon exchange. If the size of elastic B_n is a few ppm, then a few percent residual transverse polarization in the beam, combined with small broken azimuthal symmetries in the detector, would require a few ppb correction to the Q-weak data. As part of a program of B_n background studies, we made the first measurement of B_n in the N-to-Delta(1232) transition using the Q-weak apparatus. The final transverse asymmetry, corrected for backgrounds and beam polarization, was found to be B_n = 42.82 ± 2.45 (stat) ± 16.07 (sys) ppm at beam energy E_beam = 1.155 GeV, scattering angle theta = 8.3 deg, and missing mass W = 1.2 GeV. B_n from electron-nucleon scattering is a unique tool to study the gamma^* Delta Delta form factors, and this measurement will help to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process. To help correct false asymmetries from beam noise, a beam modulation system was implemented to induce small position, angle, and energy changes at the target to characterize detector response to the beam jitter. Two air-core dipoles separated by ~10 m were pulsed at a time to produce position and angle changes at the target, for virtually any tune of the beamline. The beam energy was modulated using an SRF cavity. The hardware and associated control instrumentation will be described in this dissertation. Preliminary detector sensitivities were extracted which helped to reduce the width of the measured asymmetry. The beam modulation system has also proven valuable for tracking changes in the beamline optics, such as dispersion at the target.

  10. Electron spin resonance microscopy applied to the study of controlled drug release

    Microsoft Academic Search

    Aharon Blank; Jack H. Freed; Naraharisetti Pavan Kumar; Chi-Hwa Wang

    2006-01-01

    We describe our recent developments towards 3D micron-scale imaging capability, based on electron spin resonance (ESR), and its application to the study of controlled release. The method, termed ESR microscopy (ESRM), is an extension of the conventional “millimeter-scale” ESR imaging technique. It employs paramagnetic molecules (such as stable radicals or spin-labeled drugs) and may enable one to obtain accurate 3D

  11. Controlling spin diffusion by tailored rf-irradiation schemes

    NASA Astrophysics Data System (ADS)

    Wittmann, Johannes J.; Hendriks, Lyndsey; Meier, Beat H.; Ernst, Matthias

    2014-07-01

    Spin-diffusion type polarization transfer among heteronuclei, e.g., 13C or 15N, plays an important role in many solid-state NMR experiments for structure determination of proteins. In such experiments, chemical-shift compensation is provided by the proton bath (‘proton-driven') which can be improved by radio-frequency irradiation of the protons. Here, we address the problem that the polarization-transfer rates depend not only on the intermolecular distance but also on the chemical-shift difference of the two spins. We introduce rf-modulation schemes that allow eliminating the chemical-shift dependence to a large extent over a predefined range. At the same time, the rate constants are maximized.

  12. PHYSICAL REVIEW B 87, 235202 (2013) Electrical control of phonon-mediated spin relaxation rate in semiconductor quantum dots

    E-print Network

    Melnik, Roderick

    2013-01-01

    in semiconductor quantum dots: Rashba versus Dresselhaus spin-orbit coupling Sanjay Prabhakar,1 Roderick Melnik,1 dominates over the Rashba spin-orbit coupling in GaAs and GaSb QDs, it is important to find the exact electron spin with the application of gate controlled electric fields in confined semiconductor quantum

  13. Optical Pumping and Electron Spin Resonance of Single 87Rb Atoms on Helium Nanodroplets

    NASA Astrophysics Data System (ADS)

    Koch, Markus; Poms, Johannes; Volk, Alexander; Ernst, Wolfgang E.

    2011-06-01

    Our recent development of electron spin resonance (ESR) spectroscopy on superfluid helium nanodroplets (HeN) provides a sensitive tool to investigate interactions between a surface located alkali-metal atom and an ESR silent species inside the droplet. Highest sensitivity is expected for alkali-metal atoms with large hyperfine coupling. We present hyperfine resolved ESR spectra of single 87Rb (hyperfine constant a_HFS = 3417 MHz) atoms isolated on HeN. In accordance with our previous work on 85Rb (AHFS= 1012 MHz) we find a droplet size dependent increase of AHFS between 400 and 450 ppm, due to the electronic perturbation by the helium environment. The process of optical pumping and of optical detection on HeN is investigated in detail in order to optimize the ESR signal. A simple model for optical pumping on HeN is presented, which agrees well with the experimental results. M. Koch, G. Auböck, C. Callegari, and W.E. Ernst, Phys. Rev. Lett. 103, 035302 (2009) A. Volk, J. Poms, M. Koch, and W.E. Ernst, J. Phys. Chem. A, in press

  14. Beam Normal Single Spin Asymmetry in the N-to-Delta Transition

    NASA Astrophysics Data System (ADS)

    Nuruzzaman, Nuruzzaman; Qweak Collaboration

    2013-10-01

    The Q-weak experiment in Hall C at the Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton, QWp,through the precision measurement of the parity-violating (PV) asymmetry in elastic e-p scattering at low momentum transfer. The data are currently under analysis. There is a parity conserving Beam Normal Single Spin Asymmetry or transverse asymmetry (An) on H2 with a sin(?) -like dependence due to 2- ? exchange. The size of An is few ppm, so a few percent residual transverse polarization in the beam, in addition to potentially small broken azimuthal symmetries in the detector, might lead to few ppb corrections to the Q-weak data. As part of a program of An background studies, we made the first measurement of An in the N-to-Delta transition using the Q-weak apparatus. An from electron-nucleon scattering is also a unique tool to study the ?* ?? form factors. Status of the analysis will be presented. Supported in part by the Department of Energy and the National Science Foundation

  15. Most spin-1/2 transition-metal ions do have single ion anisotropy.

    PubMed

    Liu, Jia; Koo, Hyun-Joo; Xiang, Hongjun; Kremer, Reinhard K; Whangbo, Myung-Hwan

    2014-09-28

    The cause for the preferred spin orientation in magnetic systems containing spin-1/2 transition-metal ions was explored by studying the origin of the easy-plane anisotropy of the spin-1/2 Cu(2+) ions in CuCl2·2H2O, LiCuVO4, CuCl2, and CuBr2 on the basis of density functional theory and magnetic dipole-dipole energy calculations as well as a perturbation theory treatment of the spin-orbit coupling. We find that the spin orientation observed for these spin-1/2 ions is not caused by their anisotropic spin exchange interactions, nor by their magnetic dipole-dipole interactions, but by the spin-orbit coupling associated with their crystal-field split d-states. Our study also predicts in-plane anisotropy for the Cu(2+) ions of Bi2CuO4 and Li2CuO2. The results of our investigations dispel the mistaken belief that magnetic systems with spin-1/2 ions have no magnetic anisotropy induced by spin-orbit coupling. PMID:25273418

  16. Most spin-1/2 transition-metal ions do have single ion anisotropy

    SciTech Connect

    Liu, Jia; Whangbo, Myung-Hwan, E-mail: hxiang@fudan.edu.cn, E-mail: mike-whangbo@ncsu.edu [Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695 (United States); Koo, Hyun-Joo [Department of Chemistry and Research Institute for Basic Sciences, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Xiang, Hongjun, E-mail: hxiang@fudan.edu.cn, E-mail: mike-whangbo@ncsu.edu [Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433 (China); Kremer, Reinhard K. [Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany)

    2014-09-28

    The cause for the preferred spin orientation in magnetic systems containing spin-1/2 transition-metal ions was explored by studying the origin of the easy-plane anisotropy of the spin-1/2 Cu{sup 2+} ions in CuCl{sub 2}·2H{sub 2}O, LiCuVO{sub 4}, CuCl{sub 2}, and CuBr{sub 2} on the basis of density functional theory and magnetic dipole-dipole energy calculations as well as a perturbation theory treatment of the spin-orbit coupling. We find that the spin orientation observed for these spin-1/2 ions is not caused by their anisotropic spin exchange interactions, nor by their magnetic dipole-dipole interactions, but by the spin-orbit coupling associated with their crystal-field split d-states. Our study also predicts in-plane anisotropy for the Cu{sup 2+} ions of Bi{sub 2}CuO{sub 4} and Li{sub 2}CuO{sub 2}. The results of our investigations dispel the mistaken belief that magnetic systems with spin-1/2 ions have no magnetic anisotropy induced by spin-orbit coupling.

  17. Dual regulator controls two gases from a single reference

    NASA Technical Reports Server (NTRS)

    Jackson, K.

    1966-01-01

    Dual-pressure regulator uses single reference for parallel control of two gases. The regulator uses an external fluid pressure to modulate the flow of one gas, and the regulated flow of the first gas to modulate the flow of the second.

  18. Redundant single gimbal control moment gyroscope singularity analysis

    Microsoft Academic Search

    Nazareth S. Bedrossian; Joseph Paradiso; Edward V. Bergmann; Derek Rowell

    1990-01-01

    The robotic manipulator is proposed as the mechanical analog to single gimbal control moment gyroscope systems, and it is shown that both systems share similar difficulties with singular configurations. This analogy is used to group gimbal angles corresponding to any momentum state into different families. The singularity problem associated with these systems is examined in detail. In particular, a method

  19. Magnetophoretic circuits for digital control of single particles and cells.

    PubMed

    Lim, Byeonghwa; Reddy, Venu; Hu, XingHao; Kim, KunWoo; Jadhav, Mital; Abedini-Nassab, Roozbeh; Noh, Young-Woock; Lim, Yong Taik; Yellen, Benjamin B; Kim, CheolGi

    2014-01-01

    The ability to manipulate small fluid droplets, colloidal particles and single cells with the precision and parallelization of modern-day computer hardware has profound applications for biochemical detection, gene sequencing, chemical synthesis and highly parallel analysis of single cells. Drawing inspiration from general circuit theory and magnetic bubble technology, here we demonstrate a class of integrated circuits for executing sequential and parallel, timed operations on an ensemble of single particles and cells. The integrated circuits are constructed from lithographically defined, overlaid patterns of magnetic film and current lines. The magnetic patterns passively control particles similar to electrical conductors, diodes and capacitors. The current lines actively switch particles between different tracks similar to gated electrical transistors. When combined into arrays and driven by a rotating magnetic field clock, these integrated circuits have general multiplexing properties and enable the precise control of magnetizable objects. PMID:24828763

  20. Single-Lever Power Control for General Aviation Aircraft Promises Improved Efficiency and Simplified Pilot Controls

    NASA Technical Reports Server (NTRS)

    Musgrave, Jeffrey L.

    1997-01-01

    General aviation research is leading to major advances in internal combustion engine control systems for single-engine, single-pilot aircraft. These advances promise to increase engine performance and fuel efficiency while substantially reducing pilot workload and increasing flight safety. One such advance is a single-lever power control (SLPC) system, a welcome departure from older, less user-friendly, multilever engine control systems. The benefits of using single-lever power controls for general aviation aircraft are improved flight safety through advanced engine diagnostics, simplified powerplant operations, increased time between overhauls, and cost-effective technology (extends fuel burn and reduces overhaul costs). The single-lever concept has proven to be so effective in preliminary studies that general aviation manufacturers are making plans to retrofit current aircraft with the technology and are incorporating it in designs for future aircraft.

  1. Interfacial spin-glass-like state in Mn5Ge3 single crystalline films grown on germanium substrates

    NASA Astrophysics Data System (ADS)

    Truong, A.; Watanabe, A. O.; Mortemousque, P. A.; Ando, K.; Sato, T.; Taniyama, T.; Itoh, K. M.

    2015-06-01

    Thermal irreversibility of the magnetization in Mn5Ge3 epitaxial thin films on Ge(111) is reported. The frequency dependence of the ac susceptibility demonstrates a spin-glass-like behavior, despite the fact that the thin film is a single crystal. Such glassy behavior is attributed to the presence of a "ferromagnetically dead" layer with spin-glass-like properties at the Mn5Ge3/Ge interface, which results in frustrated interactions with the ferromagnetic Mn5Ge3 . Moreover, it is shown that the magnetic phase diagram in the H -T plane of the glassy state is very sensitive to the growth conditions. Variation in the growth temperature and film thickness changes the spin-glass-like properties and the Curie temperature. The sensitivity of the glassy state to the growth conditions is related to the variation in the properties of the interfacial layer.

  2. Single spin-torque vortex oscillator using combined bottom-up approach and e-beam lithography

    NASA Astrophysics Data System (ADS)

    Abreu Araujo, F.; Piraux, L.; Antohe, V. A.; Cros, V.; Gence, L.

    2013-06-01

    A combined bottom-up assembly of electrodeposited nanowires and electron beam lithography technique has been developed to investigate the spin transfer torque and microwave emission on specially designed nanowires containing a single Co/Cu/Co pseudo spin valve. Microwave signals have been obtained even at zero magnetic field. Interestingly, high frequency vs. magnetic field tunability was demonstrated, in the range 0.4-2 MHz/Oe, depending on the orientation of the applied magnetic field relative to the magnetic layers of the pseudo spin valve. The frequency values and the emitted signal frequency as a function of the external magnetic field are in good quantitative agreement with the analytical vortex model as well as with micromagnetic simulations.

  3. Optimal open-loop and feedback control using single gimbal control moment gyroscopes

    NASA Technical Reports Server (NTRS)

    Hoelscher, Brian R.; Vadali, Srinvas R.

    1993-01-01

    Methods for control of spacecraft maneuvers through the use of single gimbal control moment gyroscopes are developed. The development employs an integrated model of the spacecraft dynamics with the control moment gyroscope dynamics. Smooth and continuous open-loop control profiles are obtained which minimize a weighted function of maneuver time, magnitude of control effort, and proximity to singular gimbal configurations. Closed-loop state feedback control laws are derived by invoking Lyapunov stability theory. The schemes are presented for implementing the commanded state feedback: gimbal rate control and gimbal acceleration control. The appropriate handling of singular gimbal configurations is also discussed.

  4. Two methods of temperature control for single-molecule measurements.

    PubMed

    Baker, Matthew A B; Inoue, Yuichi; Takeda, Kuniaki; Ishijima, Akihiko; Berry, Richard M

    2011-05-01

    Modern single-molecule biophysical experiments require high numerical aperture oil-immersion objectives in close contact with the sample. We introduce two methods of high numerical aperture temperature control which can be implemented on any microscope: objective temperature control using a ring-shaped Peltier device, and stage temperature control using a fluid flow cooling chip in close thermal contact with the sample. We demonstrate the efficacy of each system by showing the change in speed with temperature of two molecular motors, the bacterial flagellar motor and skeletal muscle myosin. PMID:21279639

  5. Spinning Reserves from Controllable Packaged Through the Wall Air Conditioner (PTAC) Units

    SciTech Connect

    Kirby, B.J.

    2003-04-02

    This report summarizes the feasibility of providing spinning reserves from packaged through the wall air conditioning (PTAC) units. Spinning reserves, together with non-spinning reserves, compose the contingency reserves; the essential resources that the power system operator uses to restore the generation and load balance and maintain bulk power system reliability in the event of a major generation or transmission outage. Spinning reserves are the fastest responding and most expensive reserves. Many responsive load technologies could (and we hope will) be used to provide spinning reserve. It is also easier for many loads (including air conditioning loads) to provide the relatively shorter and less frequent interruptions required to respond to contingencies than it is for them to reduce consumption for an entire peak period. Oak Ridge National Laboratory (ORNL) is conducting research on obtaining spinning reserve from large pumping loads and from residential and small commercial thermostat controlled heating, ventilation and air conditioning (HVAC) units. The technology selected for this project, Digi-Log's retrofit PTAC controller, offers significant advantages. To evaluate the availability of spinning reserve capacity from responsive heating and air conditioning loads, ORNL obtained data from a number of units operating over a year at a motel in the TVA service territory. A total of 24 PTAC units in as many rooms were fitted with Digi-Log's supervisory control unit that could be controlled from the motel front desk. Twelve of the rooms formed the group in which the controller was controlled from the hotel front desk only. The remaining twelve rooms were controlled by the occupant and formed the uncontrolled group. This enables us to evaluate the spinning reserve capacity from PTACS that were operating normally and from those under active energy management. A second generation of the Digi-Log controller that will respond quickly enough to provide spinning reserve has been designed but not yet manufactured. Manufacture of these units is pending arrival of funds from NYSERDA. The new Digi-Log equipment will utilize satellite signals from Skytel to activate the controller from a remote site by the ISO and to respond to curtailment events. PTACs account for approximately 3% of the total commercial cooling load in the US, equivalent to an average energy consumption rate of 3,000 MW with peak consumption being significantly higher. Hence PTACs alone represent a sizable opportunity for providing spinning reserves from load. The residential buildings sector cooling and heating load averages about 33,000 MW, more than 10 times the commercial PTAC load. The buildings sector represents an even greater opportunity than the PTAC commercial sector for providing spinning reserves from load. Technology to implement load curtailment and monitor its effect already exists and can readily be further customized to meet ISO and utility needs. Further research is needed to prove the technical feasibility of PTAC units and other small loads providing spinning reserves. Aggregation, communication, control, and monitoring issues remain to be addressed. If the technical issues can be resolved however, it is likely that system operators, loads, and regulators will have significant incentives to resolve these other resources since spinning reserve from load has the potential to provide large benefits to each community.

  6. Spin-Photon Entangling Diode

    E-print Network

    Christian Flindt; Anders S. Sorensen; Mikhail D. Lukin; Jacob M. Taylor

    2007-03-05

    We propose a semiconductor device that can electrically generate entangled electron spin-photon states, providing a building block for entanglement of distant spins. The device consists of a p-i-n diode structure that incorporates a coupled double quantum dot. We show that electronic control of the diode bias and local gating allow for the generation of single photons that are entangled with a robust quantum memory based on the electron spins. Practical performance of this approach to controlled spin-photon entanglement is analyzed.

  7. The importance of strain on spin-spin coupling in Pr5/8Ca3/8MnO3 single crystal film

    SciTech Connect

    Fu, Xinwen [Shanghai University, Shanghai, Peoples R China; Gao, Yuze [Max-Planck-Institute for Solid State Research, Stuttgart, Germany; Wu, Zhiwei [Shanghai University, Shanghai, Peoples R China; Zhang, Jincang [Shanghai University, Shanghai, Peoples R China; Li, Qing [ORNL; Cao, Guixin [ORNL

    2012-01-01

    The influence of anisotropic strains on coupling spins is systematically investigated in pulsed laser deposited single crystal Pr5/8Ca3/8MnO3 film. The substrate was chosen to introduce tensile and compressive strain onto the film. Various experiments, i.e., zero field cooled/field cooled (ZFC/FC) magnetization measurement, hysteresis loops, and exchange bias field detection, have revealed distinct difference along two perpendicular in-plane axes which represent tensile and compressive strain orientation, respectively. We found that the observed phenomenon can be explained by the external strain effect.

  8. Spacecraft Line-of-Sight Control Using a Single Variable-Speed Control Moment Gyro

    E-print Network

    Tsiotras, Panagiotis

    exchange devices, such as reaction or momentum wheels or control moment gyros (CMGs) can be used-speed control moment gyro (VSCMG). A VSCMG is a hybrid actuator that combines a reaction/momentum wheel (RW/MW) with a single-gimbal control moment gyro [19­23]. Whereas the wheel speed of a conventional CMG is kept constant

  9. Nuclear-spin-dependent coherent population trapping of single nitrogen vacancy centers in diamond

    E-print Network

    D. Andrew Golter; Khodadad N. Dinyari; Hailin Wang

    2013-03-02

    Coherent population trapping (CPT) provides a highly sensitive means for probing the energy level structure of an atomic system. For a nitrogen vacancy center in diamond, the CPT offers an alternative to the standard optically-detected magnetic resonance method for measuring the hyperfine structure of the electronic ground states. We show that the nuclear spin dependent CPT measures directly the hyperfine splitting of these states due to the 14N nuclear spin. The CPT spectral response obtained in the presence of a strong microwave field, resonant or nearly resonant with a ground state spin transition, maps out the dynamic Stark splitting induced by the coherent spin excitation.

  10. High-quality single crystal growth and spin flop of multiferroic Co4Nb2O9

    NASA Astrophysics Data System (ADS)

    Cao, Yiming; Yang, Yali; Xiang, Maolin; Feng, Zhenjie; Kang, Baojuan; Zhang, Jincang; Ren, Wei; Cao, Shixun

    2015-06-01

    A single crystal of Co4Nb2O9 about 7 mm in diameter and 55 mm in length was successfully grown by an optical floating zone method. X-ray powder diffraction (XRD) indicates that it has a single phase corundum-type structure. Clear Laue spots and sharp XRD peaks confirm the good quality and crystallographic orientations. Below TN, magnetization of Co4Nb2O9 along a axis shows dramatically different behaviors between H=1 kOe and 20 kOe, suggesting a spin flop occurs along a axis. Ma(H) curve at 5 K shows a change of slope at a critical magnetic field of 7.5 kOe for triggering the spin flip.

  11. Electron Spin Resonance Analysis of the Nitroxide Spin Label 2,2,6,6-Tetramethylpiperidone-N-Oxyl (Tempone) in Single Crystals of the Reduced Tempone Matrix

    PubMed Central

    Snipes, Wallace; Cupp, James; Cohn, Gerald; Keith, Alec

    1974-01-01

    The nitroxide spin label Tempone (2,2,6,6-tetramethylpiperidone-N-oxyl) can be reduced with ascorbic acid to give a nonparamagnetic species. Single crystals of reduced Tempone serve as a suitable host matrix to orient trace quantities of Tempone for ESR analysis. In these crystals the majority of the Tempone molecules are well-oriented, but a smaller fraction of the molecules tumble freely to give an isotropic electron spin resonance (ESR) spectrum. ESR transitions for the oriented molecules are saturated at much lower microwave power levels than for the tumbling molecules. For the oriented molecules, an analysis of the anisotropy of the spectroscopic splitting factor (g) gives principal values of g1 = 2.0094, g2 = 2.0061, g3 = 2.0021. The hyperfine coupling tensor is nearly axially symmetric, with principal values (in gauss) of A1 = 6.5, A2 = 6.7, A3 = 33.0. Within experimental error, the principal axis systems for the g tensor and the hyperfine tensor are identical. Comparison of the average values of g and A with the isotropic values of these parameters for Tempone in solvents of different polarity suggests a method for choosing the most appropriate tensor elements to be used for spin label experiments in various solvent systems. PMID:4359744

  12. Cloning transformations in spin networks without external control

    SciTech Connect

    De Chiara, Gabriele; Fazio, Rosario; Montangero, Simone [NEST- INFM and Scuola Normale Superiore, piazza dei Cavalieri 7, I-56126 Pisa (Italy); Macchiavello, Chiara [INFM and Dipartimento di Fisica 'A. Volta', Via Bassi 6, I-27100 Pavia (Italy); Palma, G. Massimo [NEST-INFM and Dipartimento di Tecnologie dell'Informazione, Universita degli studi di Milano, via Bramante 65, I-26013 Crema, CR (Italy)

    2005-07-15

    In this paper we present an approach to quantum cloning with unmodulated spin networks. The cloner is realized by a proper design of the network and a choice of the coupling between the qubits. We show that in the case of phase covariant cloner the XY coupling gives the best results. In the 1{yields}2 cloning we find that the value for the fidelity of the optimal cloner is achieved, and values comparable to the optimal ones in the general N{yields}M case can be attained. If a suitable set of network symmetries are satisfied, the output fidelity of the clones does not depend on the specific choice of the graph. We show that spin network cloning is robust against the presence of static imperfections. Moreover, in the presence of noise, it outperforms the conventional approach. In this case the fidelity exceeds the corresponding value obtained by quantum gates even for a very small amount of noise. Furthermore, we show how to use this method to clone qutrits and qudits. By means of the Heisenberg coupling it is also possible to implement the universal cloner although in this case the fidelity is 10% off that of the optimal cloner.

  13. Performance comparison between the high-speed Yokogawa spinning disc confocal system and single-point scanning confocal systems

    Microsoft Academic Search

    E. WANG; C. M. BABBEY; K. W. DUNN

    2005-01-01

    Summary Fluorescence microscopy of the dynamics of living cells presents a special challenge to a microscope imaging system, simulta- neously requiring both high spatial resolution and high temporal resolution, but with illumination levels low enough to prevent fluorophore damage and cytotoxicity. We have compared the high-speed Yokogawa CSU10 spinning disc confocal system with several conventional single-point scanning confocal (SPSC) microscopes,

  14. Spin Quantum Tunneling in Single Molecular Magnets: Fingerprints in Transport Spectroscopy of Current and Noise

    E-print Network

    of Current and Noise C. Romeike, M. R. Wegewijs, and H. Schoeller Institut fu¨r Theoretische Physik A, RWTH. We find current and noise oscillations as a function of bias voltage due to a weak violation of spin in the nonequilibrium occupations of the magnetic states since they allow for a violation of spin-selection rules

  15. Ferroelectric control of spin injection across the ferromagnet/ferroelectric interface

    NASA Astrophysics Data System (ADS)

    Liu, Xiaohui; Burton, J. D.; Tsymbal, Evgeny

    2014-03-01

    Magnetoelectric coupling has become one of the most attractive fields in modern materials research due their promise to electrically control spintronics-based devices. Previous investigations have shown that at the ferromagnet/ferroelectric interface, magnetization could be tuned by the reversal of ferroelectric polarization. We had previously predicted that ferroelectric polarization reversal can control the nature of the resistive contact at the SrRuO3/n-BaTiO3 heterojunction interface, going from the Ohmic to Schottky regimes with reversal of ferroelectric polarization. It is known, however, that SrRuO3 displays robust ferromagnetism below the Curie temperature of about 160K. In this work, using first-principles density functional calculations, we explore the effect of ferroelectric polarization of spin-polarized transmission across the SrRuO3/n-BaTiO3 interface. Our study reveals that the interface transmission is negatively spin-polarized, and that ferroelectric polarization reversal leads to a change in spin polarization from -65% for the Ohmic contact to -98% for the Schottky contact. This sizeable change in the spin polarization could provide an interesting non-volatile mechanism to electrically control spin injection into semiconductor-based spintronics devices.

  16. Single-chain magnetic behavior in a hetero-tri-spin complex mediated by supramolecular interactions with TCNQF?? radicals.

    PubMed

    Wang, Zhao-Xi; Zhang, Xuan; Zhang, Yuan-Zhu; Li, Ming-Xing; Zhao, Hanhua; Andruh, Marius; Dunbar, Kim R

    2014-10-20

    The self-assembly of organic TCNQF?? radicals (2-fluoro-7,7,8,8-tetracyano-p-quinodimethane) and the anisotropic [Tb(valpn)Cu](3+) dinuclear cations produced a single-chain magnet (SCM) involving stacking interactions of TCNQF?? radicals (H2valpn is the Schiff base from the condensation of o-vanillin with 1,3-diaminopropane). Static and dynamic magnetic characterizations reveal that the effective energy barrier for the reversal of the magnetization in this hetero-tri-spin SCM is significantly larger than the barrier of the isolated single-molecule magnet based on the {TbCu} dinuclear core. PMID:25213266

  17. Complete All-Optical Quantum Control of Electron Spins in InAs/GaAs Quantum Dot Molecule

    E-print Network

    Guy Z. Cohen

    2015-01-08

    The spin states of electrons and holes confined in InAs quantum dot molecules have recently come to fore as a promising system for the storage or manipulation of quantum information. We describe here a feasible scheme for complete quantum optical control of two electron spin qubits in two vertically-stacked singly-charged InAs quantum dots coupled by coherent electron tunneling. With an applied magnetic field transverse to the growth direction, we construct a universal set of gates that corresponds to the possible Raman transitions between the spin states. We detail the procedure to decompose a given two-qubit unitary operation, so as to realize it with a successive application of up to 8 of these gates. We give the pulse shapes for the laser pulses used to implement this universal set of gates and demonstrate the realization of the two-qubit quantum Fourier transform with fidelity of 0.881 and duration of 414 ps. Our proposal therefore offers an accessible path to universal computation in quantum dot molecules and points to the advantages of using pulse shaping incoherent manipulation of optically active quantum dots to mitigate the negative effects of unintended dynamics and spontaneous emission.

  18. Single Electron Spin Resonance in a Si-MOS Double Quantum Dot

    NASA Astrophysics Data System (ADS)

    Hao, Xiaojie; Xiao, Ming; Jiang, Hongwen; Ruskov, Rusko; Tahan, Charles

    2013-03-01

    Pauli spin blockade is used as a means to detect the flip of spins in a silicon metal-oxide-semiconductor (MOS) based double quantum dot. Microwave driven electron spin resonance (ESR) signals, with a linewidth as narrow as 1.5 G, has been observed only in a narrow range of magnetic fields. ESR spectroscopy in the magnetic field - microwave frequency plane shows an unexpected level anti-crossing, with an energy gap of about 50 MHz. The spectral line gives an estimation of the lower bound for inhomogeneous phase decoherence time T2* of about a couple of hundred ns for individual spins in the nano-structured system with a Si/SiO2 interface. We explain the anti-crossing gap as due to spin-orbit mixing with higher states, which is also responsible for the narrow-window visibility of the ESR signal in Si based double quantum dots. Pauli spin blockade is used as a means to detect the flip of spins in a silicon metal-oxide-semiconductor (MOS) based double quantum dot. Microwave driven electron spin resonance (ESR) signals, with a linewidth as narrow as 1.5 G, has been observed only in a narrow range of magnetic fields. ESR spectroscopy in the magnetic field - microwave frequency plane shows an unexpected level anti-crossing, with an energy gap of about 50 MHz. The spectral line gives an estimation of the lower bound for inhomogeneous phase decoherence time T2* of about a couple of hundred ns for individual spins in the nano-structured system with a Si/SiO2 interface. We explain the anti-crossing gap as due to spin-orbit mixing with higher states, which is also responsible for the narrow-window visibility of the ESR signal in Si based double quantum dots. The work is supported by the U.S. Department of Defense and by ARO (w911NF-11-1-0028).

  19. A Comparison Study of Magnetic Bearing Controllers for a Fully Suspended Dynamic Spin Rig

    NASA Technical Reports Server (NTRS)

    Choi, Benjamin; Johnson, Dexter; Morrison, Carlos; Mehmed, Oral; Huff, Dennis (Technical Monitor)

    2002-01-01

    NASA Glenn Research Center (GRC) has developed a fully suspended magnetic bearing system for the Dynamic Spin Rig (DSR) that is used to perform vibration tests of turbomachinery blades and components under spinning conditions in a vacuum. Two heteropolar radial magnetic bearings and a thrust bearing and the associated control system were integrated into the DSR to provide noncontact magnetic suspension and mechanical excitation of the 35 lb vertical rotor with blades to induce turbomachinery blade vibration. A simple proportional-integral-derivative (PID) controller with a special feature for multidirectional radial excitation worked very well to both support and shake the shaft with blades. However, more advanced controllers were developed and successfully tested to determine the optimal controller in terms of sensor and processing noise reduction, smaller rotor orbits, and energy savings for the system. The test results of a variety of controllers we demonstrated up to the rig's maximum allowable speed of 10,000 rpm are shown.

  20. Spin-dependent localized Hartree-Fock density-functional calculation of singly, doubly, and triply excited and Rydberg states of He and Li-like ions

    Microsoft Academic Search

    Zhongyuan Zhou; Shih-I. Chu

    2005-01-01

    A spin-dependent density-functional approach for the calculation of highly and multiply excited state of atomic system is proposed based on the localized Hartree-Fock density-functional method and Slater's diagonal sum rule. In this approach, electron spin orbitals in an electronic configuration are obtained first by solving the Kohn-Sham equation with an exact nonvariational spin-dependent localized Hartree-Fock exchange potential. Then a single-Slater-determinant

  1. Determination of ground state properties in quantum spin systems by single qubit unitary operations and entanglement excitation energies

    E-print Network

    S. M. Giampaolo; F. Illuminati; P. Verrucchi; S. De Siena

    2007-12-21

    We introduce a method for analyzing ground state properties of quantum many body systems, based on the characterization of separability and entanglement by single subsystem unitary operations. We apply the method to the study of the ground state structure of several interacting spin-1/2 models, described by Hamiltonians with different degrees of symmetry. We show that the approach based on single qubit unitary operations allows to introduce {\\it ``entanglement excitation energies''}, a set of observables that can characterize ground state properties, including the quantification of single-site entanglement and the determination of quantum critical points. The formalism allows to identify the existence and location of factorization points, and a purely quantum {\\it ``transition of entanglement''} that occurs at the approach of factorization. This kind of quantum transition is characterized by a diverging ratio of excitation energies associated to single-qubit unitary operations.

  2. Controlling single-molecule junction conductance by molecular interactions

    PubMed Central

    Kitaguchi, Y.; Habuka, S.; Okuyama, H.; Hatta, S.; Aruga, T.; Frederiksen, T.; Paulsson, M.; Ueba, H.

    2015-01-01

    For the rational design of single-molecular electronic devices, it is essential to understand environmental effects on the electronic properties of a working molecule. Here we investigate the impact of molecular interactions on the single-molecule conductance by accurately positioning individual molecules on the electrode. To achieve reproducible and precise conductivity measurements, we utilize relatively weak ?-bonding between a phenoxy molecule and a STM-tip to form and cleave one contact to the molecule. The anchoring to the other electrode is kept stable using a chalcogen atom with strong bonding to a Cu(110) substrate. These non-destructive measurements permit us to investigate the variation in single-molecule conductance under different but controlled environmental conditions. Combined with density functional theory calculations, we clarify the role of the electrostatic field in the environmental effect that influences the molecular level alignment. PMID:26135251

  3. Electrically controllable single-photon switch based on graphene.

    PubMed

    Sun, Lu; Jiang, Chun

    2015-06-20

    We propose an electrically controllable single-photon switch that consists of a graphene nanoribbon side-coupled to a dynamically modulated graphene nanodisk. With a harmonic modulation of graphene conductivity induced by the gate voltage, interband photonic transition between two eigenstates of the nanodisk is introduced, which leads to extraordinary single-photon transport properties such as electromagnetically induced transparency-like phenomena. This effect is utilized to realize a highly efficient single-photon switch. With properly designed parameters, numerical results show that an extinction ratio of up to 20.8 dB can be achieved. The influence of the coupling strength between nanoribbon and nanodisk, the coupling strength between two eigenstates of the nanodisk, and dissipations in the nanodisk are also investigated in this paper. PMID:26193009

  4. Controlling single-molecule junction conductance by molecular interactions.

    PubMed

    Kitaguchi, Y; Habuka, S; Okuyama, H; Hatta, S; Aruga, T; Frederiksen, T; Paulsson, M; Ueba, H

    2015-01-01

    For the rational design of single-molecular electronic devices, it is essential to understand environmental effects on the electronic properties of a working molecule. Here we investigate the impact of molecular interactions on the single-molecule conductance by accurately positioning individual molecules on the electrode. To achieve reproducible and precise conductivity measurements, we utilize relatively weak ?-bonding between a phenoxy molecule and a STM-tip to form and cleave one contact to the molecule. The anchoring to the other electrode is kept stable using a chalcogen atom with strong bonding to a Cu(110) substrate. These non-destructive measurements permit us to investigate the variation in single-molecule conductance under different but controlled environmental conditions. Combined with density functional theory calculations, we clarify the role of the electrostatic field in the environmental effect that influences the molecular level alignment. PMID:26135251

  5. Entanglement between nitrogen vacancy spins in diamond controlled by a nanomechanical resonator

    E-print Network

    L. Chotorlishvili; D. Sander; A. Sukhov; V. Dugaev; V. R. Vieira; A. Komnik; J. Berakdar

    2013-01-17

    We suggest a new type of nano-electromechanical resonator, the functionality of which is based on a magnetic field induced deflection of an appropriate cantilever that oscillates between nitrogen vacancy (NV) spins in daimond. Specifically, we consider a Si(100) cantilever coated with a thin magnetic Ni film. Magnetoelastic stress and magnetic-field induced torque are utilized to induce a controlled cantilever deflection. It is shown that, depending on the value of the system parameters, the induced asymmetry of the cantilever deflection substantially modifies the characteristics of the system. In particular, the coupling strength between the NV spins and the degree of entanglement can be controlled through magnetoelastic stress and magnetic-field induced torque effects. Our theoretical proposal can be implemented experimentally with the potential of increasing several times the coupling strength between the NV spins as compared to the maximal coupling strength reported before in P. Rabl, et al. Phys. Rev. B 79, 041302(R) (2009).

  6. Design and control of electron transport properties of single molecules

    PubMed Central

    Pan, Shuan; Fu, Qiang; Huang, Tian; Zhao, Aidi; Wang, Bing; Luo, Yi; Yang, Jinlong; Hou, Jianguo

    2009-01-01

    We demonstrate in this joint experimental and theoretical study how one can alter electron transport behavior of a single melamine molecule adsorbed on a Cu (100) surface by performing a sequence of elegantly devised and well-controlled single molecular chemical processes. It is found that with a dehydrogenation reaction, the melamine molecule becomes firmly bonded onto the Cu surface and acts as a normal conductor controlled by elastic electron tunneling. A current-induced hydrogen tautomerization process results in an asymmetric melamine tautomer, which in turn leads to a significant rectifying effect. Furthermore, by switching on inelastic multielectron scattering processes, mechanical oscillations of an N-H bond between two configurations of the asymmetric tautomer can be triggered with tuneable frequency. Collectively, this designed molecule exhibits rectifying and switching functions simultaneously over a wide range of external voltage. PMID:19706435

  7. Electronic control inside a molecule : towards single molecule devices

    NASA Astrophysics Data System (ADS)

    Lastapis, Mathieu; Fukuma, Yurie; Boland, John

    2006-03-01

    The chimerical single molecule engineering has been proven to be accessible through the use of scanning tunnelling microscopy (STM) [1]. In this field, one particularly attractive area is the study of single molecules adsorbed on semiconductor surfaces. It has been recently demonstrated that a spatial fine control of the molecular dynamics is possible through the use of tunnelling current [2]. In order to improve the electronic control of a single molecule, we are currently investigating a promising system: CaF2 on Si(111). This system has been extensively studied as a model system to deposit insulator on silicon. Here we are using this system to electronically decouple the molecule from the substrate. I will present LT STM experiments on atomically thick CaF islands on Si(111). The measured electronic properties of these islands demonstrate their potential as ideal templates to study single molecules. Finally I will present some preliminary results on N-HBC [3] adsorbed on a CaF island. [1] G. Binnig and H. Rohrer, ``In touch with atoms'', Rev. Mod. Phys. 71, S324-S330 (1999) [2] M. Lastapis et al, Science, 308, 1000 (2005) [3] S.Draper et al, JACS, 126, 8694 (2004)

  8. Intrinsic Quantum Noise in Faraday Rotation Measurements of a Single Electron Spin

    E-print Network

    Yanjun Ma; Jeremy Levy

    2008-10-31

    Faraday rotation is one way to realize quantum non-demolition measurement of electron spin in quantum dots. To describe Faraday rotation, semiclassical models are typically used, based on quantized electron spin states and classical electromagnetic fields. Such treatments neglect the entanglement between electronic and photonic degrees of freedom that produce intrinsic quantum noise, limiting the ultimate sensitivity of this technique. We present a fully quantum-mechanical description of Faraday rotation, and quantify this intrinsic noise. A method for measuring the purity of a given spin state is suggested based on this analysis.

  9. Quantum Hall Charge Sensor for Single-Donor Nuclear Spin Detection in Silicon

    E-print Network

    D. Sleiter; N. Y. Kim; K. Nozawa; T. D. Ladd; M. L. W. Thewalt; Y. Yamamoto

    2010-05-12

    We propose a novel optical and electrical hybrid scheme for the measurement of nuclear spin qubits in silicon. By combining the environmental insensitivity of the integer quantum Hall effect with the optically distinguishable hyperfine states of phosphorus impurities in silicon, our system can simultaneously offer nuclear spin measurement and robustness against environmental defects. 31P donor spins in isotopically purified 28Si are often discussed as very promising quantum memory qubits due to their extremely long decoherence times, and our proposed device offers an effective implementation for such a quantum memory system.

  10. Optical pumping of the electronic and nuclear spin of single charge-tunable quantum dots.

    PubMed

    Bracker, A S; Stinaff, E A; Gammon, D; Ware, M E; Tischler, J G; Shabaev, A; Efros, Al L; Park, D; Gershoni, D; Korenev, V L; Merkulov, I A

    2005-02-01

    We present a comprehensive examination of optical pumping of spins in individual GaAs quantum dots as we change the net charge from positive to neutral to negative with a charge-tunable heterostructure. Negative photoluminescence polarization memory is enhanced by optical pumping of ground state electron spins, which we prove with the first measurements of the Hanle effect on an individual quantum dot. We use the Overhauser effect in a high longitudinal magnetic field to demonstrate efficient optical pumping of nuclear spins for all three charge states of the quantum dot. PMID:15783594

  11. PUBLISHED ONLINE: 21 OCTOBER 2012 | DOI: 10.1038/NPHYS2457 Production of spin-controlled rare isotope beams

    E-print Network

    Loss, Daniel

    -controlled rare isotope beams Yuichi Ichikawa1 * , Hideki Ueno1 , Yuji Ishii2 , Takeshi Furukawa3 , Akihiro propose a method for controlling spin in a system of rare isotopes which takes advantage of the mechanism% was achieved for the spin of a rare isotope 32 Al. The figure of merit for the present method was found

  12. Factors controlling hole injection in single conjugated polymer molecules.

    PubMed

    Fradkin, Leonid; Palacios, Rodrigo E; Bolinger, Joshua C; Lee, Kwang-Jik; Lackowski, William M; Barbara, Paul F

    2009-04-23

    New insights on the molecular level details of the recently reported light-assisted injection of positive charge into single conjugated polymer chains are reported. Extensive new fluorescence-voltage single molecule spectroscopy (FV-SMS) measurements were performed on single chains of the archetypical conjugated polymer MEH-PPV embedded in a capacitor device to complement previous studies of the influence of the bias scan rate and optical excitation intensity. The use of a vacuum microscope allowed for the precise control of the device atmosphere, demonstrating the influence of triplet states in the MEH-PPV on the FV-SMS modulation. For identical device conditions, little variation was observed in the rate and yield of charging from molecule to molecule. Through the use of thicker supporting matrices and insulating polymer "blocking layers", it was determined that good electrical contact between the hole transport layers and the single molecules was necessary for charge injection. The results demonstrate the complexity of charge transfer processes at the interface of organic semiconductors and highlight the ability of single molecule methods to advance the understanding of such processes at the nanoscale. PMID:19260669

  13. Control Laws for a Dual-Spin Stabilized Platform

    NASA Technical Reports Server (NTRS)

    Lim, K. B.; Moerder, D. D.

    2008-01-01

    This paper describes two attitude control laws suitable for atmospheric flight vehicles with a steady angular momentum bias in the vehicle yaw axis. This bias is assumed to be provided by an internal flywheel, and is introduced to enhance roll and pitch stiffness. The first control law is based on Lyapunov stability theory, and stability proofs are given. The second control law, which assumes that the angular momentum bias is large, is based on a classical PID control. It is shown that the large yaw-axis bias requires that the PI feedback component on the roll and pitch angle errors be cross-fed. Both control laws are applied to a vehicle simulation in the presence of disturbances for several values of yaw-axis angular momentum bias. It is seen that both control laws provide a significant improvement in attitude performance when the bias is sufficiently large, but the nonlinear control law is also able to provide improved performance for a small value of bias. This is important because the smaller bias corresponds to a smaller requirement for mass to be dedicated to the flywheel.

  14. Electric-field controlled spin in bilayer triangular graphene quantum dots

    Microsoft Academic Search

    A. D. Güçlü; P. Potasz; P. Hawrylak

    2011-01-01

    We present theoretical results based on mean-field and exact many-body approaches showing that in bilayer triangular graphene quantum dots with zigzag edges, the magnetism can be controlled by an external vertical electric field. We demonstrate that without electric field, the spins of the two layers of the quantum dot interact ferromagnetically. At a critical value of the electric field, the

  15. Storing quantum information in XXZ spin rings with periodically time-controlled interactions

    Microsoft Academic Search

    S. M. Giampaolo; F. Illuminati; G. Mazzarella

    2005-01-01

    We introduce a general scheme to realize massive quantum memories in simple systems of interacting qubits. Such systems are described by spin rings with XXZ intersite couplings of suitably time-periodically controlled amplitudes. We show that initially localized excitations undergo perfect periodic revivals, allowing for the simultaneous storage of arbitrary sets of different local states. This novel approach to the problem

  16. Spin-controlled coexistence of 0 and ? states in SFSFS Josephson junctions

    NASA Astrophysics Data System (ADS)

    Alidoust, Mohammad; Halterman, Klaus

    2014-05-01

    Using the Keldysh-Usadel formalism, we theoretically study the 0-? transition profiles and current-phase relations of magnetic SFSFS and SFSFFS Josephson nanojunctions in the diffusive regime. By allowing the magnetizations of the ferromagnetic layers to take arbitrary orientations, the strength and direction of the charge supercurrent flowing through the ferromagnetic regions can be controlled via the magnetization rotation in one of the ferromagnetic layers. Depending on the junction parameters, we find opposite current flow in the ferromagnetic layers, revealing that, remarkably, such configurations possess well-controlled 0 and ? states simultaneously, creating a three-terminal 0-? spin switch. We demonstrate that the spin-controlled 0-? profiles trace back to the proximity induced odd-frequency superconducting correlations generated by the ferromagnetic layers. It is also shown that the spin-switching effect can be more pronounced in SFSFFS structures. The current-phase relations reveal the important role of the middle S electrode, where the spin-controlled supercurrent depends crucially on its thickness and phase differences with the outer S terminals.

  17. MEETING SCIENCE REQUIREMENTS FOR ATTITUDE DETERMINATION AND CONTROL IN A LOW-POWER, SPINNING NANOSATELLITE

    Microsoft Academic Search

    Phill-Sun Hur; Robert G. Melton; David B. Spencer

    this paper describes the attitude determination and control system for a nanosatellite (30 kg), using geomagnetic field data and solar panels as sun sensors, applied to a spinning nanosatellite (Penn State University's LionSat). LionSat will map plasma densities in the ram and wake of the vehicle's path, using two hybrid plasma probes that rotate with the spacecraft. Attitude will be

  18. Constrained Active Space Unrestricted Mean-Field Approaches for Controlling Spin-Contamination

    NASA Astrophysics Data System (ADS)

    Tsuchimochi, Takashi; Scuseria, Gustavo E.

    2011-03-01

    We have recently shown that unrestricted Hartree-Fock (UHF) variationally reduces to high-spin restricted open-shell Hartree-Fock when constraints are imposed on the eigenvalues of the spin density matrix [T. Tsuchimochi and G. E. Scuseria, J. Chem. Phys. 133, 141102 (2010)]. We here generalize these ideas and propose to control spin-contamination in UHF by releasing the constraints in an active space while imposing them elsewhere. If the active space is properly chosen, our constrained UHF (CUHF) method greatly benefits from a controlled broken-symmetry effect while avoiding the massive spin contamination arising in the traditional UHF. We apply L o .. wdin's projection operator to CUHF and obtain multireference wave functions with moderate computational cost. We report results on singlet-triplet energy gaps to show that our constrained scheme outperforms fully unrestricted methods. This constrained approach can be readily used in Kohn-Sham (KS) density functional theory with similar favorable effects, provided that spin-contamination is given by the KS orbitals as in UHF.

  19. Forward Neutral Pion Transverse Single Spin Asymmetries in p+p Collisions at sqrt s = 200 GeV

    SciTech Connect

    STAR Coll

    2008-11-26

    We report precision measurements of the Feynman-x (x{sub F}) dependence, and first measurements of the transverse momentum (p{sub T}) dependence, of transverse single spin asymmetries for the production of {pi}{sup 0} mesons from polarized proton collisions at {radical}s = 200 GeV. The x{sub F} dependence of the results are in fair agreement with perturbative QCD (pQCD) model calculations that identify orbital motion of quarks and gluons within the proton as the origin of the spin effects. Results for the p{sub T} dependence at fixed x{sub F} are not consistent with these same pQCD-based calculations.

  20. Finite-horizon control-constrained nonlinear optimal control using single network adaptive critics.

    PubMed

    Heydari, Ali; Balakrishnan, Sivasubramanya N

    2013-01-01

    To synthesize fixed-final-time control-constrained optimal controllers for discrete-time nonlinear control-affine systems, a single neural network (NN)-based controller called the Finite-horizon Single Network Adaptive Critic is developed in this paper. Inputs to the NN are the current system states and the time-to-go, and the network outputs are the costates that are used to compute optimal feedback control. Control constraints are handled through a nonquadratic cost function. Convergence proofs of: 1) the reinforcement learning-based training method to the optimal solution; 2) the training error; and 3) the network weights are provided. The resulting controller is shown to solve the associated time-varying Hamilton-Jacobi-Bellman equation and provide the fixed-final-time optimal solution. Performance of the new synthesis technique is demonstrated through different examples including an attitude control problem wherein a rigid spacecraft performs a finite-time attitude maneuver subject to control bounds. The new formulation has great potential for implementation since it consists of only one NN with single set of weights and it provides comprehensive feedback solutions online, though it is trained offline. PMID:24808214

  1. Controlling spins and photons For fundamentally secure communication

    E-print Network

    van der Wal, Caspar H.

    (2014) [2] The quantum internet, H. J. Kimble, Nature 453, 1023 (2008). [3] Privacy and the Quantum. The internet is now used for com- municating and controlling credit card transactions, personal e cur- rently in use for cryptography (such as HTTPS internet traffic) are secure [1]. Research

  2. Attitude determination, control and navigation of a spinning satellite

    Microsoft Academic Search

    J. J. Rodden

    1983-01-01

    This study examines the concepts of autonomous spacecraft navigation, attitude determination and control. Navigation in orbit requires a minimum of two independent horizon to celestial body measurements that are correlated with time to establish a position in orbit over the earth. Sensor systems applicable for navigation are combinations of one sun sensor, star sensor, horizon sensor and clock, or star

  3. Coherent control of atomic spin currents in a double well

    E-print Network

    Chu, Shih-I; Ng, H. T.

    2012-02-27

    We propose a method for controlling the atomic currents of a two-component Bose-Einstein condensate in a double well by applying an external field to the atoms in one of the potential wells. We study the ground-state ...

  4. Constrained active space unrestricted mean-field methods for controlling spin-contamination

    NASA Astrophysics Data System (ADS)

    Tsuchimochi, Takashi; Scuseria, Gustavo E.

    2011-02-01

    We have recently proposed a novel approach for obtaining high-spin restricted open-shell Hartree-Fock wave functions by imposing constraints on the unrestricted Hartree-Fock (UHF) method [T. Tsuchimochi and G. E. Scuseria, J. Chem. Phys. 133, 141102 (2010)]. We here extend these ideas to the case where the constraints are released in an active space but imposed elsewhere. If the active space is properly chosen, our constrained UHF (CUHF) method greatly benefits from a controlled broken-symmetry effect while avoiding the massive spin contamination of traditional UHF. We also revisit and apply L{ddot{o}}wdin's projection operator to CUHF and obtain multireference wave functions with moderate computational cost. We report singlet-triplet energy splittings showing that our constrained scheme outperforms fully unrestricted methods. This constrained approach can be readily used in spin density functional theory with similar favorable effects.

  5. Isolation and Control of Spins in Silicon Carbide with Millisecond-Coherence Times

    NASA Astrophysics Data System (ADS)

    Christle, David J.; Falk, Abram L.; Andrich, Paolo; Klimov, Paul V.; Awschalom, David D.; Hassan, Jawad Ul; Son, Nguyen T.; Janzén, Erik; Ohshima, Takeshi

    2015-03-01

    The elimination of defects from silicon carbide (SiC) has facilitated its move to the forefront of the optoelectronics and power-electronics industries. Nonetheless, because the electronic states of SiC defects can have sharp optical and spin transitions, they are increasingly recognized as a valuable resource for quantum-information and nanoscale-sensing applications. We demonstrate that individual electronic spin states of the divacancy defect in highly purified monocrystalline 4H-SiC can be isolated and coherently controlled. This defect has analogous behavior to the prominent nitrogen-vacancy center in diamond, yet exists in a material amenable to modern growth and microfabrication techniques. We spectroscopically identify the different forms of divacancies, and show that divacancy spins exhibit an exceptionally long ensemble Hahn-echo coherence time that exceeds one millisecond. Funding by NSF, AFOSR MURI, and the Knut & Alice Wallenberg Foundation is gratefully acknowledged.

  6. Controlled suppression of superconductivity by the generation of polarized Cooper pairs in spin-valve structures

    NASA Astrophysics Data System (ADS)

    Flokstra, M. G.; Cunningham, T. C.; Kim, J.; Satchell, N.; Burnell, G.; Curran, P. J.; Bending, S. J.; Kinane, C. J.; Cooper, J. F. K.; Langridge, S.; Isidori, A.; Pugach, N.; Eschrig, M.; Lee, S. L.

    2015-02-01

    Transport measurements are presented on thin-film superconducting spin-valve systems, where the controlled noncollinear arrangement of two ferromagnetic Co layers can be used to influence the superconducting state of Nb. We observe a very clear oscillation of the superconducting transition temperature with the relative orientation of the two ferromagnetic layers. Our measurements allow us to distinguish between the competing influences of domain averaging, stray dipolar fields, and the formation of superconducting spin triplets. Domain averaging is shown to lead to a weak enhancement of transition temperature for the antiparallel configuration of exchange fields, while much larger changes are observed for other configurations, which can be attributed to drainage currents due to spin triplet formation.

  7. Spin control by application of electric current and voltage in FeCo-MgO junctions.

    PubMed

    Suzuki, Yoshishige; Kubota, Hitoshi; Tulapurkar, Ashwin; Nozaki, Takayuki

    2011-09-28

    Efficient control and detection of spins are the most important tasks in spintronics. The current and voltage applied to a magnetic tunnel junction may exert a torque on the magnetic thin layer in the junction and cause its reversal or continuous precession. The discovery of the giant tunnelling magnetoresistance effect in ferromagnetic tunnelling junctions using an MgO barrier enabled us to obtain a large signal output from the magnetization reversal and precession. Also, the interplay of large spin configuration-electric conduction coupling provides highly nonlinear effects like the spin-torque diode effect. The negative resistance effect and amplification using it are predicted. A new discovery about a voltage-induced magnetic anisotropy change in Fe ultrathin films is also discussed. PMID:21859728

  8. Control and measurements of spin and carrier dynamics in InAs films

    NASA Astrophysics Data System (ADS)

    Nontapot, Kanokwan; Kini, Rajeev; Khodaparast, Giti; Guido, Louis; Welser, Roger

    2007-03-01

    In light of the growing interest in spin-related phenomena and devices, there is now renewed interest in the science and engineering of narrow gap semiconductors. We report control and measurements of spin and carrier relaxations in InAs (100) and InAs (111) films with doping densities of ˜ 3x10^12 cm-2 (mobility ˜20,000 cm^2/Vs at 77 K) and 2.0x10^12 cm-2 (mobility ˜33,00 cm^2/Vs at 77 K) at room temperature and 77K, respectively. We use standard pump-probe and magneto-optical Kerr effect (MOKE) spectroscopy at different excitation wavelengths, power densities, and temperatures. Spin relaxations in these structures demonstrate dynamics which is different from the carrier relaxations under the same experimental conditions. We explain our results using the Elliot-Yafet picture which is considered to be the dominant relaxation process in narrow gap semiconductors.

  9. Fiber-optical switch controlled by a single atom

    E-print Network

    Danny O'Shea; Christian Junge; Jürgen Volz; Arno Rauschenbeutel

    2013-09-12

    We demonstrate highly efficient switching of optical signals between two optical fibers controlled by a single atom. The key element of our experiment is a whispering-gallery mode bottle microresonator, which is coupled to a single atom and interfaced by two tapered fiber couplers. Even in the presence of the coupling fibers, the atom--resonator system reaches the strong coupling regime of cavity quantum electrodynamics (CQED), leading to a vacuum Rabi splitting in the excitation spectrum. We systematically investigate the switching efficiency of our system, i.e., the probability that the CQED fiber-optical switch redirects the light into the desired output. We obtain a large redirection efficiency reaching a raw fidelity of more than 60% without post-selection.

  10. PHYSICAL REVIEW A 89, 013805 (2014) Single-photon router: Coherent control of multichannel scattering for single photons

    E-print Network

    Nori, Franco

    2014-01-01

    PHYSICAL REVIEW A 89, 013805 (2014) Single-photon router: Coherent control of multichannel 2013; published 7 January 2014) We propose a single-photon router using a single atom with an inversion quantum channels formed with 1D CRWs has been proposed as a quantum router [9], where * Corresponding

  11. Spin polarons in La{sub 1-x}Sr{sub x}CoO{sub 3} single crystals.

    SciTech Connect

    Smith, R. X.; Hoch, M. J. R.; Kuhns, P. L.; Moulton, W. G.; Reyes, A. P.; Boebinger, G. S.; Mitchell, J.; Leighton, C.; Florida State Univ.; Univ. of Minnesota

    2008-01-01

    Nanoscale inhomogeneity in La{sub 1-x}Sr{sub x}CoO{sub 3} has been investigated in single-crystal samples for 0.05 {le} x {le} 0.30 using {sup 139}La and {sup 59}Co NMR to probe local magnetization. In contrast to polycrystalline samples, single crystals exhibit ferromagnetism only above the metal-insulator critical concentration x{sub C} = 0.17. However, over the entire doping range, the single crystals exhibit an unusually broad and asymmetric distribution of hyperfine fields, evidencing (local) spin-polaron formation that persists to temperatures as high as 200 K, well above the glass transition reported previously from bulk magnetization. Above x{sub C} the asymmetry decreases rapidly with increasing doping as polarons overlap to give rise to long-range ferromagnetism. A modified phase diagram is presented. The key features of the data are reproduced by a simple model in which Sr dopants trigger spin-polaron formation, a physical picture first proposed by de Gennes [Phys. Rev. 118, 141 (1960)].

  12. Single Spin Asymmetries on a transversely polarised proton target at COMPASS

    E-print Network

    S. Levorato; for the COMPASS Collaboration

    2008-08-04

    COMPASS is a running fixed-target experiment at the CERN SPS with a rich physics program focused on nucleon spin structure and on hadron spectroscopy. One of the main goals of the spin program is the measurement of the transverse spin effects in semi-inclusive DIS off transversely polarised nucleons. In the years 2002, 2003 and 2004 data have been taken using a 160 $GeV/c$ naturally polarised $\\mu^{+}$ beam and a deuterium target ($^{6}LiD$) transversely polarised respect to the beam direction. In 2007 the run year has been devoted to collect data with a proton ($NH_{3}$) target. The preliminary results for the Collins and Sivers asymmetries, extracted from the 2007 data with transverse target polarisation, are presented here. Results are also compared with existing model predictions.

  13. Controlled synthesis of single-chirality carbon nanotubes.

    PubMed

    Sanchez-Valencia, Juan Ramon; Dienel, Thomas; Gröning, Oliver; Shorubalko, Ivan; Mueller, Andreas; Jansen, Martin; Amsharov, Konstantin; Ruffieux, Pascal; Fasel, Roman

    2014-08-01

    Over the past two decades, single-walled carbon nanotubes (SWCNTs) have received much attention because their extraordinary properties are promising for numerous applications. Many of these properties depend sensitively on SWCNT structure, which is characterized by the chiral index (n,m) that denotes the length and orientation of the circumferential vector in the hexagonal carbon lattice. Electronic properties are particularly strongly affected, with subtle structural changes switching tubes from metallic to semiconducting with various bandgaps. Monodisperse 'single-chirality' (that is, with a single (n,m) index) SWCNTs are thus needed to fully exploit their technological potential. Controlled synthesis through catalyst engineering, end-cap engineering or cloning strategies, and also tube sorting based on chromatography, density-gradient centrifugation, electrophoresis and other techniques, have delivered SWCNT samples with narrow distributions of tube diameter and a large fraction of a predetermined tube type. But an effective pathway to truly monodisperse SWCNTs remains elusive. The use of template molecules to unambiguously dictate the diameter and chirality of the resulting nanotube holds great promise in this regard, but has hitherto had only limited practical success. Here we show that this bottom-up strategy can produce targeted nanotubes: we convert molecular precursors into ultrashort singly capped (6,6) 'armchair' nanotube seeds using surface-catalysed cyclodehydrogenation on a platinum (111) surface, and then elongate these during a subsequent growth phase to produce single-chirality and essentially defect-free SWCNTs with lengths up to a few hundred nanometres. We expect that our on-surface synthesis approach will provide a route to nanotube-based materials with highly optimized properties for applications such as light detectors, photovoltaics, field-effect transistors and sensors. PMID:25100481

  14. Single transverse-spin asymmetry for D-meson production in semi-inclusive deep inelastic scattering

    SciTech Connect

    Kang Zhongbo; Qiu Jianwei [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)

    2008-08-01

    We study the single transverse-spin asymmetry for open charm production in the semi-inclusive lepton-hadron deep inelastic scattering. We calculate the asymmetry in terms of the QCD collinear factorization approach for D mesons at high enough P{sub hperpendicular} and find that the asymmetry is proportional to the twist-three trigluon correlation function in the proton. With a simple model for the trigluon correlation function, we estimate the asymmetry for both COMPASS and eRHIC kinematics and discuss the possibilities of extracting the trigluon correlation function in these experiments.

  15. Quantum Control of the Hyperfine Spin of a Cs Atom Ensemble

    SciTech Connect

    Chaudhury, Souma; Herr, Tobias; Jessen, Poul S. [College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States); Merkel, Seth; Silberfarb, Andrew; Deutsch, Ivan H. [Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2007-10-19

    We demonstrate quantum control of a large spin angular momentum associated with the F=3 hyperfine ground state of {sup 133}Cs. Time-dependent magnetic fields and a static tensor light shift are used to implement near-optimal controls and map a fiducial state to a broad range of target states, with yields in the range 0.8-0.9. Squeezed states are produced also by an adiabatic scheme that is more robust against errors. Universal control facilitates the encoding and manipulation of qubits and qudits in atomic ground states and may lead to the improvement of some precision measurements.

  16. Single-Spin Magnetometry with Multipulse Sensing Sequences G. de Lange,1

    E-print Network

    implemented, such as super- conducting quantum interference devices (SQUIDS) [1], Hall sensors [2], sensors derive and experimentally verify the optimal number of sensing cycles, for which the effects field to be detected shifts the energy levels of the spin through the Zeeman effect. When a superposi

  17. High-dynamic-range magnetometry with a single nuclear spin in diamond

    E-print Network

    Pfeifer, Holger

    and measurement techniques2,3,5 because of its optical spin polariz- ation and readout mechanism10 , long-dependent energy difference is measured by monitoring the evolution of the corresponding phase f / Bt, where BT). If this priorinformation aboutthemagnetic fieldisnotavailable, estimation of B cannot be performed. To summarize, shorter

  18. Single neuron control over a complex motor program.

    PubMed Central

    Frost, W N; Katz, P S

    1996-01-01

    While there are many instances of single neurons that can drive rhythmic stimulus-elicited motor programs, such neurons have seldom been found to be necessary for motor program function. In the isolated central nervous system of the marine mollusc Tritonia diomedea, brief stimulation (1 sec) of a peripheral nerve activates an interneuronal central pattern generator that produces the long-lasting (approximately 30-60 sec) motor program underlying the animal's rhythmic escape swim. Here, we identify a single interneuron, DRI (for dorsal ramp interneuron), that (i) conveys the sensory information from this stimulus to the swim central pattern generator, (ii) elicits the swim motor program when driven with intracellular stimulation, and (iii) blocks the depolarizing "ramp" input to the central pattern generator, and consequently the motor program itself, when hyperpolarized during the nerve stimulus. Because most of the sensory information appears to be funneled through this one neuron as it enters the pattern generator, DRI presents a striking example of single neuron control over a complex motor circuit. Images Fig. 1 PMID:8552652

  19. Attitude determination, control and navigation of a spinning satellite

    NASA Astrophysics Data System (ADS)

    Rodden, J. J.

    This study examines the concepts of autonomous spacecraft navigation, attitude determination and control. Navigation in orbit requires a minimum of two independent horizon to celestial body measurements that are correlated with time to establish a position in orbit over the earth. Sensor systems applicable for navigation are combinations of one sun sensor, star sensor, horizon sensor and clock, or star sensor, horizon sensor and clock. The clock is necessary to correlate inertial position with the earth's rotation. Star sensor measurements have distinct advantages over use of a sun sensor. A star sensor provides a higher rate of usable data than a sun sensor because there are more celestial objects for it to detect. Star and horizon sensor data combinations allow independent and concurrent navigation and attitude determination.

  20. Dynamic control of spin states in interacting magnetic elements

    DOEpatents

    Jain, Shikha; Novosad, Valentyn

    2014-10-07

    A method for the control of the magnetic states of interacting magnetic elements comprising providing a magnetic structure with a plurality of interacting magnetic elements. The magnetic structure comprises a plurality of magnetic states based on the state of each interacting magnetic element. The desired magnetic state of the magnetic structure is determined. The active resonance frequency and amplitude curve of the desired magnetic state is determined. Each magnetic element of the magnetic structure is then subjected to an alternating magnetic field or electrical current having a frequency and amplitude below the active resonance frequency and amplitude curve of said desired magnetic state and above the active resonance frequency and amplitude curve of the current state of the magnetic structure until the magnetic state of the magnetic structure is at the desired magnetic state.

  1. All-electrical coherent control of the exciton states in a single quantum dot

    NASA Astrophysics Data System (ADS)

    Boyer de La Giroday, A.; Bennett, A. J.; Pooley, M. A.; Stevenson, R. M.; Sköld, N.; Patel, R. B.; Farrer, I.; Ritchie, D. A.; Shields, A. J.

    2010-12-01

    We demonstrate high-fidelity reversible transfer of quantum information from the polarization of photons into the spin state of an electron-hole pair in a semiconductor quantum dot. Moreover, spins are electrically manipulated on a subnanosecond time scale, allowing us to coherently control their evolution. By varying the area of the electrical pulse, we demonstrate phase-shift and spin-flip gate operations with near-unity fidelities. Our system constitutes a controllable quantum interface between flying and stationary qubits, an enabling technology for quantum logic in the solid state.

  2. Controlled permeation of cell membrane by single bubble acoustic cavitation

    PubMed Central

    Zhou, Y.; Yang, K.; Cui, J.; Ye, J. Y.; Deng, C. X.

    2011-01-01

    Sonoporation is the membrane disruption generated by ultrasound and has been exploited as a non-viral strategy for drug and gene delivery. Acoustic cavitation of microbubbles has been recognized to play an important role in sonoporation. However, due to the lack of adequate techniques for precise control of cavitation activities and real-time assessment of the resulting sub-micron process of sonoporation, limited knowledge has been available regarding the detail processes and correlation of cavitation with membrane disruption at the single cell level. In the current study, we developed a combined approach including optical, acoustic, and electrophysiological techniques to enable synchronized manipulation, imaging, and measurement of cavitation of single bubbles and the resulting cell membrane disruption in real-time. Using a self-focused femtosecond laser and high frequency (7.44 MHz) pulses, a single microbubble was generated and positioned at a desired distance from the membrane of a Xenopus oocyte. Cavitation of the bubble was achieved by applying a low frequency (1.5 MHz) ultrasound pulse (duration 13.3 or 40 µs) to induce bubble collapse. Disruption of the cell membrane was assessed by the increase in the transmembrane current (TMC) of the cell under voltage clamp. Simultaneous high-speed bright field imaging of cavitation and measurements of the TMC were obtained to correlate the ultrasound-generated bubble activities with the cell membrane poration. The change in membrane permeability was directly associated with the formation of a sub-micrometer pore from a local membrane rupture generated by bubble collapse or bubble compression depending on ultrasound amplitude and duration. The impact of the bubble collapse on membrane permeation decreased rapidly with increasing distance (D) between the bubble (diameter d) and the cell membrane. The effective range of cavitation impact on membrane poration was determined to be D/d = 0.75. The maximum mean radius of the pores was estimated from the measured TMC to be 0.106 ± 0.032 µm (n = 70) for acoustic pressure of 1.5 MPa (duration 13.3 µs), and increased to 0.171 ± 0.030 µm (n = 125) for acoustic pressure of 1.7 MPa and to 0.182 ± 0.052 µm (n=112) for a pulse duration of 40 µs (1.5 MPa). These results from controlled cell membrane permeation by cavitation of single bubbles revealed insights and key factors affecting sonoporation at the single cell level. PMID:21945682

  3. Mammalian monogamy is not controlled by a single gene

    PubMed Central

    Fink, Sabine; Excoffier, Laurent; Heckel, Gerald

    2006-01-01

    Complex social behavior in Microtus voles and other mammals has been postulated to be under the direct genetic control of a single locus: the arginine vasopressin 1a receptor (avpr1a) gene. Using a phylogenetic approach, we show that a repetitive element in the promoter region of avpr1a, which reportedly causes social monogamy, is actually widespread in nonmonogamous Microtus and other rodents. There was no evidence for intraspecific polymorphism in regard to the presence or absence of the repetitive element. Among 25 rodent species studied, the element was absent in only two closely related nonmonogamous species, indicating that this absence is certainly the result of an evolutionarily recent loss. Our analyses further demonstrate that the repetitive structures upstream of the avpr1a gene in humans and primates, which have been associated with social bonding, are evolutionarily distinct from those in rodents. Our evolutionary approach reveals that monogamy in rodents is not controlled by a single polymorphism in the promoter region of the avpr1a gene. We thus resolve the contradiction between the claims for an evolutionarily conserved genetic programming of social behavior in mammals and the vast evidence for highly complex and flexible mating systems. PMID:16832060

  4. Sign Flip of Single Transverse Spin Asymmetries in Drell-Yan and DIS: The Role of Cuts and Complex Phases

    NASA Astrophysics Data System (ADS)

    Sievert, Matthew; Brodsky, Stanley; Hwang, Dae Sung; Kovchegov, Yuri; Schmidt, Ivan

    2013-04-01

    The transverse polarization of a hadron's spin can couple to its partons' transverse momentum distribution, resulting in an asymmetry known as the Sivers asymmetry. Depending on the scattering mechanism, this asymmetry of the parton distribution may persist into the final-state hadron distribution. Such single transverse spin asymmetries provide unique insights into the internal spin structure of hadrons and can couple to different scattering processes than the usual unpolarized cross-section. One hallmark prediction of transverse-momentum-dependent factorization is that the Sivers asymmetry should have equal magnitude and opposite sign between the Drell-Yan process and semi-inclusive deep inelastic scattering. We explicitly verify this prediction in greater detail than had previously been considered, using a toy model for the proton wave function. With an explicit representation of the transverse spinors, we demonstrate how C/P/T invariance couples the asymmetry to the imaginary part, or cut, of the diagrams. To establish the validity of the predicted sign flip, we demonstrate a non-trivial equivalence between the cuts present in deep inelastic scattering and the Drell-Yan process.

  5. Cotunneling spectroscopy and the properties of excited-state spin manifolds of Mn12 single molecule magnets

    NASA Astrophysics Data System (ADS)

    Rostamzadeh Renani, Fatemeh; Kirczenow, George

    2014-10-01

    We study charge transport through single molecule magnet (SMM) junctions in the cotunneling regime as a tool for investigating the properties of the excited-state manifolds of neutral Mn12 SMs. This study is motivated by a recent transport experiment [S. Kahle et al., Nano Lett. 12, 518 (2012), 10.1021/nl204141z] that probed the details of the magnetic and electronic structure of Mn12 SMMs beyond the ground-state spin manifold. A giant spin Hamiltonian and master equation approach is used to explore theoretically the cotunneling transport through Mn12-Ac SMM junctions. We identify SMM transitions that can account for both the strong and weak features of the experimental differential conductance spectra. We find the experimental results to imply that the excited spin-state manifolds of the neutral SMM have either different anisotropy constants or different g factors in comparison with its ground-state manifold. However, the latter scenario accounts best for the experimental data.

  6. Spin-stabilized satellite magnetic attitude control scheme without initial detumbling

    NASA Astrophysics Data System (ADS)

    Roldugin, D. S.; Testani, P.

    2014-01-01

    The angular motion of an axisymmetrical satellite equipped with an active magnetic attitude control system is considered. The dynamics of the satellite are analytically studied on the whole control loop. The control loop is as follows: preliminary reorientation along with nutation damping, spinning about the axis of symmetry, then precise reorientation of the axis of symmetry in inertial space. Reorientation starts right after separation from the launch vehicle. Active magnetic attitude control system time-response with respect to its parameters is analyzed. It is proven that low-inclined orbit forces low control system time-response. Comparison with the common control scheme shows the time-response gain. Numerical analysis of the disturbances effect is carried out and good pointing accuracy is proved.

  7. Electrical control of the spin polarization of a current in ``pure-carbon'' systems based on partially hydrogenated graphene nanoribbon

    NASA Astrophysics Data System (ADS)

    Guo, Yan-Dong; Yan, Xiao-Hong; Xiao, Yang

    2013-06-01

    Controlling a spin current by electrical means and eliminating the use of ferromagnetic contacts becomes a focus of research in spintronics, as compared with conventional magnetic control methods, electrical one could reduce the dimensions and energy consumption of integrated devices. Inspired by recent progress of controlling the hydrogenation on graphene [Xie et al., Appl. Phys. Lett. 98, 193113 (2011)], we investigate the electronic structure and spin-current transport of partially hydrogenated zigzag graphene nanoribbon (ZGNR) with various hydrogenation geometries, through first-principles calculations. It is found that for ZGNR in ferromagnetic edge-coupling state, near-edge hydrogenation would suppress the magnetization on the edge of ZGNR, and lower down the transmission around EF to zero except two peaks, which reside discretely on both sides of EF with opposite spins. Based on this feature, we propose and demonstrate a three-terminal device, where the spin polarization of the current can be modulated by gate voltage (Vg) to vary from (almost) 100% to -100%, which could serve as a perfect electrically-controlled "pure-carbon" dual-spin filter. Especially, the spin polarization varies gradually with Vg, so a current with any ratio of spin-up to spin-down electron numbers can be achieved. Moreover, the influences of ZGNR width and hydrogenation-region length on the system's performance are also discussed and a large range of ZGNR configurations are found to be suitable for the application of such a device.

  8. Quantum Interference Control of Ballistic Pure Spin Currents in Semiconductors Martin J. Stevens and Arthur L. Smirl*

    E-print Network

    Van Driel, Henry M.

    ], and ballistic injection from scanning tunneling microscopes [1]. Moreover, spin-polarized carrier populations] recently predicted that there should be no net spin injected and no net charge current injected. However; published 4 April 2003) We demonstrate all-optical quantum interference injection and control of a ballistic

  9. Optimal open-loop and feedback control of spacecraft using single gimbal control moment gyroscopes 

    E-print Network

    Hoelscher, Brian Ray

    1992-01-01

    the desired final orientation and angular velocity of the spacecraft at the end of the maneuver. The terminal constraint functions are the following: 'P(x(1)) = where Q and mr are the commanded final state. Note that Pp is kinematically constrained...OPTIMAL OPEN-LOOP AND FEEDBACK CONTROL OF SPACECRAFT USING SINGLE GIMBAL CONTROL MOMENT GYROSCOPES A Thesis by Brian Ray Hoelscher Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirement...

  10. Feedback control and steering laws for spacecraft using single gimbal control moment gyros 

    E-print Network

    Oh, Hwa-Suk

    1988-01-01

    to circumvent this problem is to avoid the singularity. Several avoidance techniques have been proposed and proven effective in particular cases. Horvever, application of these avoidance techniques for maneuvering spacecraft reveals several defects...FEEDBACK CONTROL AND STEERING LAWS FOR SPACECRAFT USING SINGLE GIMBAL CONTROL MOMENT GYROS A Thesis by HWA-SUK OH Submitted to the Office of Graduate Studies oi' Texas AS=M University in partial fulfillment of the requirement for the degree...

  11. Rashba Spin-Orbit Anisotropy and the Electric Field Control of Magnetism

    PubMed Central

    Barnes, Stewart E.; Ieda, Jun'ichi; Maekawa, Sadamichi

    2014-01-01

    The control of the magnetism of ultra-thin ferromagnetic layers using an electric field, rather than a current, has many potential technologically important applications. It is usually insisted that such control occurs via an electric field induced surface charge doping that modifies the magnetic anisotropy. However, it remains the case that a number of key experiments cannot be understood within such a scenario. Much studied is the spin-splitting of the conduction electrons of non-magnetic metals or semi-conductors due to the Rashba spin-orbit coupling. This reflects a large surface electric field. For a magnet, this same splitting is modified by the exchange field resulting in a large magnetic anisotropy energy via the Dzyaloshinskii-Moriya mechanism. This different, yet traditional, path to an electrically induced anisotropy energy can explain the electric field, thickness, and material dependence reported in many experiments. PMID:24531151

  12. Exploiting environmental torques for attitude control and determination of spin stabilized satellites

    NASA Technical Reports Server (NTRS)

    Gluck, R.

    1974-01-01

    Design techniques are presented which exploit environmental torques for attitude control and determination of spin stabilized satellites. The techniques are applicable to satellite missions where the dominant environmental torques are well understood and lend themselves to accurate analytical modeling. The techniques were applied to the Particles and Fields subsatellites of the Apollo 15 and 16 spacecraft and the flight results show good agreement with the attitude determination estimates obtained.

  13. Spin transport in graphene

    NASA Astrophysics Data System (ADS)

    Özyilmaz, Barbaros

    2012-02-01

    Conventional electronic transistors involve the control of electronic charge at the nanoscale to realize memory, logic and communication functions. All these electronic charges, however, also carry a spin that remains unutilized in present commercial devices. This has motivated the search for new materials that propagate spin-polarized currents over large distances. Among the most promising materials for spintronics has been graphene. Micron-scale spin relaxation lengths have been previously demonstrated in single-layer graphene. Recently, we showed that bilayer graphene is a far more interesting candidate for spintronics. By fabricating spin valves on bilayer graphene we have achieved at room temperature spin relaxation times up to 2 nanoseconds, which are an order of magnitude higher than for single layer graphene [1]. Furthermore, the spin-relaxation time scales inversely with the mobility of BLG sample. This indicates the importance of D'yakonov-Perel' spin scattering in BLG. Last not but least, the presence of an electric field tunable band gap in bilayer graphene makes it particularly appealing. Our work provides fundamental insight into the unique properties of bilayer graphene for spintronic applications. Remarkably, a similar difference between single layer and bilayer graphene is also observed in large area graphene grown by the CVD method on copper. These results demonstrate the potential of CVD graphene in realistic spintronics devices [2]. [4pt] [1] T - Y. Yang et al., Observation of Long Spin-Relaxation Times in Bilayer Graphene at Room Temperature, PRL (2011). [0pt] [2] A. Avsar et al., Towards Wafer Scale Fabrication of Graphene Based Spin Valve Devices, Nano Lett. (2011).

  14. An electron spin resonance study of chromium, manganese and iron in single crystals of lead fluoride

    Microsoft Academic Search

    K. K. Chan; L. Shields

    1969-01-01

    Cr3+, Mn2+, Fe2+ and Fe3+ have been crystallized in PbF2 from the melt. A preponderance of Cr3+ occupied substitutional sites with the excess positive charge compensated by an excess fluoride ion in the next-nearest-neighbour interstitial position, yielding the electron spin resonance characteristics g = 1·984±0·005 and fine splitting D = 0·334±0·005 cm-1. Mn2+, for which g = 2·002±0·002 and 55A

  15. A 3% Measurement of the Beam Normal Single Spin Asymmetry in Forward Angle Elastic Electron-Proton Scattering using the Qweak Setup

    SciTech Connect

    Waidyawansa, Dinayadura Buddhini [OHIO U.

    2013-08-01

    The beam normal single spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable of the imaginary part of the two-photon exchange process. Moreover, it is a potential source of false asymmetry in parity violating electron scattering experiments. The Q{sub weak} experiment uses parity violating electron scattering to make a direct measurement of the weak charge of the proton. The targeted 4% measurement of the weak charge of the proton probes for parity violating new physics beyond the Standard Model. The beam normal single spin asymmetry at Q{sub weak} kinematics is at least three orders of magnitude larger than 5 ppb precision of the parity violating asymmetry. To better understand this parity conserving background, the Q{sub weak} Collaboration has performed elastic scattering measurements with fully transversely polarized electron beam on the proton and aluminum. This dissertation presents the analysis of the 3% measurement (1.3% statistical and 2.6% systematic) of beam normal single spin asymmetry in electronproton scattering at a Q2 of 0.025 (GeV/c)2. It is the most precise existing measurement of beam normal single spin asymmetry available at the time. A measurement of this precision helps to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process.

  16. Investigation on spin-orbit torque induced perpendicular switching through voltage controlled magnetism

    NASA Astrophysics Data System (ADS)

    Bi, Chong; Xu, Meng; Rosales, Marcus; Newhouse-Illige, Ty; Almasi, Hamid; Wang, Weigang

    2015-03-01

    Spin-orbit torques are shown to induce perpendicular magnetic switching in ultrathin ferromagnets (FMs) adjacent to heavy metals (HMs). Here, we demonstrated that the critical current density (Jc) for such perpendicular switching in HM/FM/oxide structures can be dramatically modulated by gate voltage induced reversible oxidation at FM/oxide interfaces. Through controlling perpendicular anisotropy and saturation magnetization (Ms) of FM layer, respectively, we show Ms, rather than anisotropy field as suggested in macrospin model, dominates Jc. Moreover, the measured external field dependent Jc results indicate that the spin-orbit torques have either a bulk or interface origin under different magnetization states. These results not only provide a promising means toward energy-efficient switching, but also offer further insights in understanding the reversal mechanism of the ferromagnetic layer. This work was supported in part by NSF (ECCS-1310338) and by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA. This work was supported in part by NSF (ECCS-1310338) and by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA.

  17. Laterally localizing potential as a tool for controlling the electron spin relaxation time in GaAs quantum wells

    SciTech Connect

    Larionov, A. V., E-mail: larionov@issp.ac.ru [Russian Academy of Sciences, Institute of Solid State Physics (Russian Federation); Il’in, A. I. [Russian Academy of Sciences, Institute of Microelectronics Technology and High-Purity Materials (Russian Federation)

    2013-12-15

    The coherent spin dynamics of electrons localized in a plane of GaAs quantum wells is studied experimentally by the application of an electrically controlled potential. The localizing potential is produced with the use of a metal gate with submicrometer windows deposited onto the sample surface. The photoinduced spin Kerr effect is used to study the electron spin lifetime as a function of the temperature, applied bias, and magnetic field for gates with different sets of windows. It is shown that, with an electrically controlled laterally localizing potential, it is possible to gradually change the electron spin lifetime from several hundreds of picoseconds to several tens of nanoseconds. The dependence of the electron spin relaxation time on the sizes of the lateral localization region is in good qualitative agreement with theoretical prediction.

  18. Cryogenic High-Frequency Readout and Control Platform for Spin Qubits

    E-print Network

    J. I. Colless; D. J. Reilly

    2011-11-29

    We have developed a cryogenic platform for the control and readout of spin qubits that comprises a high density of dc and radio frequency sample interconnects based on a set of coupled printed circuit boards. The modular setup incorporates 24 filtered dc lines, 14 control and readout lines with bandwidth from dc to above 6 GHz, and 2 microwave connections for excitation to 40 GHz. We report the performance of this platform, including signal integrity and crosstalk measurements and discuss design criteria for constructing sample interconnect technology needed for multi-qubit devices.

  19. Redundant single gimbal control moment gyroscope singularity analysis

    NASA Technical Reports Server (NTRS)

    Bedrossian, Nazareth S.; Paradiso, Joseph; Bergmann, Edward V.; Rowell, Derek

    1990-01-01

    The robotic manipulator is proposed as the mechanical analog to single gimbal control moment gyroscope systems, and it is shown that both systems share similar difficulties with singular configurations. This analogy is used to group gimbal angles corresponding to any momentum state into different families. The singularity problem associated with these systems is examined in detail. In particular, a method is presented to test for the possibility of nontorque-producing gimbal motion at a singular configuration, as well as to determine the admissible motions in the case when this is possible. Sufficient conditions are derived for instances where the singular system can be reconfigured into a nonsingular state by these nontorque-producing motions.

  20. Probing and controlling fluorescence blinking of single semiconductor nanoparticles

    PubMed Central

    Ko, Hsien-Chen; Yuan, Chi-Tsu; Tang, Jau

    2011-01-01

    In this review we present an overview of the experimental and theoretical development on fluorescence intermittency (blinking) and the roles of electron transfer in semiconductor crystalline nanoparticles. Blinking is a very interesting phenomenon commonly observed in single molecule/particle experiments. Under continuous laser illumination, the fluorescence time trace of these single nanoparticles exhibit random light and dark periods. Since its first observation in the mid-1990s, this intriguing phenomenon has attracted wide attention among researchers from many disciplines. We will first present the historical background of the discovery and the observation of unusual inverse power-law dependence for the waiting time distributions of light and dark periods. Then, we will describe our theoretical modeling efforts to elucidate the causes for the power-law behavior, to probe the roles of electron transfer in blinking, and eventually to control blinking and to achieve complete suppression of the blinking, which is an annoying feature in many applications of quantum dots as light sources and fluorescence labels for biomedical imaging. PMID:22110871

  1. Modelling a single phase voltage controlled rectifier using Laplace transforms

    NASA Technical Reports Server (NTRS)

    Kraft, L. Alan; Kankam, M. David

    1992-01-01

    The development of a 20 kHz, AC power system by NASA for large space projects has spurred a need to develop models for the equipment which will be used on these single phase systems. To date, models for the AC source (i.e., inverters) have been developed. It is the intent of this paper to develop a method to model the single phase voltage controlled rectifiers which will be attached to the AC power grid as an interface for connected loads. A modified version of EPRI's HARMFLO program is used as the shell for these models. The results obtained from the model developed in this paper are quite adequate for the analysis of problems such as voltage resonance. The unique technique presented in this paper uses the Laplace transforms to determine the harmonic content of the load current of the rectifier rather than a curve fitting technique. Laplace transforms yield the coefficient of the differential equations which model the line current to the rectifier directly.

  2. Dynamics of a light aircraft in spin

    Microsoft Academic Search

    Zdobys?aw Goraj; Alfred Baron; Jan Kacprzyk

    2002-01-01

    This paper focuses mainly on the experimental and in-flight spin investigations for an executive light airplane, named I-23 and built in the Institute of Aviation (Warsaw, Poland). It is a single-engine, all composite, straight wing, retractable undercarriage, conventional configuration and flight control system airplane. In-flight spin tests confirmed good rudder and elevator effectiveness for spin recovery in a wide range

  3. Single-photon router: Coherent Control of multi-channel scattering for single-photons with quantum interferences

    E-print Network

    Jing Lu; Lan Zhou; Le-man Kuang; Franco Nori

    2014-01-11

    We propose a single-photon router using a single atom with an inversion center coupled to quantum multichannels made of coupled-resonator waveguides. We show that the spontaneous emission of the atom can direct single photons from one quantum channel into another. The on-demand classical field perfectly switches-off the single-photon routing due to the quantum interference in the atomic amplitudes of optical transitions. Total reflections in the incident channel are due to the photonic bound state in the continuum. Two virtual channels, named as scatter-free and controllable channels, are found, which are coherent superpositions of quantum channels. Any incident photon in the scatter-free channel is totally transmitted. The propagating states of the controllable channel are orthogonal to those of the scatter-free channel. Single photons in the controllable channel can be perfectly reflected or transmitted by the atom.

  4. Spacecraft Angular Velocity and Line-of-Sight Control Using A Single-Gimbal Variable-Speed Control

    E-print Network

    Tsiotras, Panagiotis

    single-gimbal Variable-Speed Control Moment Gyro (VSCMG) due to the conservation of the angular momentum devices, such as reaction or momentum wheels or control moment gyros (CMGs) can also be used for attitude and Astronautics #12;wheel (RW/MW) with a single-gimbal control moment gyro.30­34 Whereas the wheel speed

  5. Theory of Spin-Orbit Enhanced Electric-Field Control of Magnetism in Multiferroic BiFeO3

    NASA Astrophysics Data System (ADS)

    de Sousa, Rogério; Allen, Marc; Cazayous, Maximilien

    2013-06-01

    We present a microscopic theory that shows the importance of spin-orbit coupling in perovskite compounds with heavy ions. In BiFeO3 (BFO) the spin-orbit coupling at the bismuth ion sites results in a special kind of magnetic anisotropy that is linear in the applied E field. This interaction can convert the cycloid ground state into a homogeneous antiferromagnet, with a weak ferromagnetic moment whose orientation can be controlled by the E-field direction. Remarkably, the E-field control of magnetism occurs without poling the ferroelectric moment, providing a pathway for reduced energy dissipation in spin-based devices made of insulators.

  6. Manipulating femtosecond spin-orbit torques with laser pulse sequences to control magnetic memory states and ringing

    NASA Astrophysics Data System (ADS)

    Lingos, P. C.; Wang, J.; Perakis, I. E.

    2015-05-01

    Femtosecond (fs) coherent control of collective order parameters is important for nonequilibrium phase dynamics in correlated materials. Here, we propose such control of ferromagnetic order based on using nonadiabatic optical manipulation of electron-hole (e -h ) photoexcitations to create fs carrier-spin pulses with controllable direction and time profile. These spin pulses are generated due to the time-reversal symmetry breaking arising from nonperturbative spin-orbit and magnetic exchange couplings of coherent photocarriers. By tuning the nonthermal populations of exchange-split, spin-orbit-coupled semiconductor band states, we can excite fs spin-orbit torques that control complex magnetization pathways between multiple magnetic memory states. We calculate the laser-induced fs magnetic anisotropy in the time domain by using density matrix equations of motion rather than the quasiequilibrium free energy. By comparing to pump-probe experiments, we identify a "sudden" out-of-plane magnetization canting displaying fs magnetic hysteresis, which agrees with switchings measured by the static Hall magnetoresistivity. This fs transverse spin-canting switches direction with magnetic state and laser frequency, which distinguishes it from the longitudinal nonlinear optical and demagnetization effects. We propose that sequences of clockwise or counterclockwise fs spin-orbit torques, photoexcited by shaping two-color laser-pulse sequences analogous to multidimensional nuclear magnetic resonance (NMR) spectroscopy, can be used to timely suppress or enhance magnetic ringing and switching rotation in magnetic memories.

  7. Point and Control: The Intuitive Method to Control Multi-device with Single Remote Control

    Microsoft Academic Search

    Sung Soo Hong; Ju Il Eom

    2009-01-01

    Remote controls are mainly used to control most of the CE devices in home environment these days. As the number of electronic\\u000a devices increases in home, each device’s corresponding remote may also be added, and user frequently controls several devices\\u000a at one time. This situation makes a user feel difficulty in finding desired remote control among many of other controllers.

  8. On the trade-off between control rate and congestion in single server systems

    E-print Network

    Modiano, Eytan H.

    The goal of this paper is to characterize the tradeoff between the rate of control and network congestion for flow control policies. We consider a simple model of a single server queue with congestion-based flow control. ...

  9. Congestion control schemes for single and parallel TCP flows in high bandwidth-delay product networks 

    E-print Network

    Cho, Soohyun

    2006-08-16

    In this work, we focus on congestion control mechanisms in Transmission Control Protocol (TCP) for emerging very-high bandwidth-delay product networks and suggest several congestion control schemes for parallel and single-flow ...

  10. Improving Control of a Dual-Duct Single-Fan Variable Air Volume Systems 

    E-print Network

    Wei, G.; Martinez, J.; Minihan, T.; Brundidge, T.; Claridge, D. E.; Turner, W. D.

    2003-01-01

    This paper discusses improved control strategies for dual-duct single-fan variable air volume (VAV) systems. Common control strategy for supply air volume modulation is evaluated, and an improved air volume control strategy that maintains separate...

  11. Brillouin light scattering study of current controlled spin waves in magnetic microstrips

    NASA Astrophysics Data System (ADS)

    Liu, Jason; Haldar, Arabinda; Buchanan, Kristen; Schultheiss, Helmut; Vogt, Katrin

    2011-10-01

    Spin wave excitations in Permalloy (Py) microstrips were investigated using micro-Brillouin light scattering (micro-BLS). Micro-BLS is a technique that can be used to probe dynamic excitations in magnetic structures on sub-micrometer length scales through inelastic scattering of light with the spin waves. The spin wave dispersion relation is typically controlled via the application of an external magnetic field using an electromagnet. For nanoscale circuits, this means that the external field is spatially uniform. Since the orientation of the field with respect to the wires in the circuit is important, restrictions are placed on what geometries can be studied. This paper will present preliminary measurements on an alternate strategy for applying the magnetic field that is more flexible. A dc control magnetic field is applied locally to a long magnetic nanowire of Py by sending a current through a gold wire deposited under the Py nanowire. The orientation of the dc field is always perpendicular to the wire, thus a favorable geometry can be maintained even in curved wires.

  12. Mass property control of a spin stabilized spacecraft with restrictive mission and weight constraints

    NASA Technical Reports Server (NTRS)

    Lang, W. E.; Ardvini, C.

    1985-01-01

    In the primary experiment of the spin stabilized San Marco D/L spacecraft, the drag effects on a light spherical shell coupled to a relatively massive center body will be measured. To achieve the precise mass property control, the centroids of both the shell and the center body must coincide with each other and with the center of pressure of the shell. Precise spin balancing is needed for launch and orbital stability, and the deployable antennas need accurate alignment. Corrective measures, developed after the preliminary mass measurements showed flaws in the mass property control, are described in detail. Inertia booms and a yo-yo despin system were developed as add-on units, spin balance measurements about all three geometric axes were used to define weight minimized correction within the outer shell envelope, and boom tip mass differentials were optimized for the most favorable inertia ratio margin achievable within the mission weight constraints. The weight versus orbital lifetime trade-offs were also considered.

  13. Scaling of dynamical decoupling for a single electron spin in nanodiamonds at room temperature

    NASA Astrophysics Data System (ADS)

    Liu, Dong-Qi; Liu, Gang-Qin; Chang, Yan-Chun; Pan, Xin-Yu

    2014-01-01

    Overcoming the spin qubit decoherence is a challenge for quantum science and technology. We investigate the decoherence process in nanodiamonds by Carr-Purcell-Meiboom-Gill (CPMG) technique at room temperature. We find that the coherence time T2 scales as n?. The elongation effect of coherence time can be represented by a constant power of the number of pulses n. Considering the filter function of CPMG decoupling sequence as a ? function, the spectrum density of noise has been reconstructed directly from the coherence time measurements and a Lorentzian noise power spectrum model agrees well with the experiment. These results are helpful for the application of nanodiamonds to nanoscale magnetic imaging.

  14. Universal quantum computation with ordered spin-chain networks

    SciTech Connect

    Tserkovnyak, Yaroslav [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Loss, Daniel [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

    2011-09-15

    It is shown that anisotropic spin chains with gapped bulk excitations and magnetically ordered ground states offer a promising platform for quantum computation, which bridges the conventional single-spin-based qubit concept with recently developed topological Majorana-based proposals. We show how to realize the single-qubit Hadamard, phase, and {pi}/8 gates as well as the two-qubit controlled-not (cnot) gate, which together form a fault-tolerant universal set of quantum gates. The gates are implemented by judiciously controlling Ising exchange and magnetic fields along a network of spin chains, with each individual qubit furnished by a spin-chain segment. A subset of single-qubit operations is geometric in nature, relying on control of anisotropy of spin interactions rather than their strength. We contrast topological aspects of the anisotropic spin-chain networks to those of p-wave superconducting wires discussed in the literature.

  15. Controllable Curved Mirrors Made from Single-Layer EAP Films

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart

    2004-01-01

    A document proposes that lightweight, deployable, large-aperture, controllable curved mirrors made of reflectively coated thin electroactive-polymer (EAP) films be developed for use in spaceborne microwave and optical systems. In these mirrors, the EAP films would serve as both structures and actuators. EAPs that are potentially suitable for such use include piezoelectric, electrostrictive, ferroelectric, and dielectric polymers. These materials exhibit strains proportional to the squares of applied electric fields. Utilizing this phenomenon, a curved mirror according to the proposal could be made from a flat film, upon which a nonuniform electrostatic potential (decreasing from the center toward the edge) would be imposed to obtain a required curvature. The effect would be analogous to that of an old-fashioned metalworking practice in which a flat metal sheet is made into a bowl by hammering it repeatedly, the frequency of hammer blows decreasing with distance from the center. In operation, the nonuniform electrostatic potential could be imposed by use of an electron gun. Calculations have shown that by use of a single- layer film made of a currently available EAP, it would be possible to control the focal length of a 2-m-diameter mirror from infinity to 1.25 m.

  16. Spin 1 frustrated antiferromagnet with biquadratic exchange and single ion anisotropy

    NASA Astrophysics Data System (ADS)

    Pires, A. S. T.

    2012-10-01

    The zero temperature properties, using the bond operator technique, are determined for the frustrated S=1 Heisenberg antiferromagnetic model plus nearest-neighbor biquadratic exchange interaction and single ion anisotropy on a two dimensional square lattice.

  17. Controlling spin-dependent tunneling by bandgap tuning in epitaxial rocksalt MgZnO films

    NASA Astrophysics Data System (ADS)

    Li, D. L.; Ma, Q. L.; Wang, S. G.; Ward, R. C. C.; Hesjedal, T.; Zhang, X.-G.; Kohn, A.; Amsellem, E.; Yang, G.; Liu, J. L.; Jiang, J.; Wei, H. X.; Han, X. F.

    2014-12-01

    Widespread application of magnetic tunnel junctions (MTJs) for information storage has so far been limited by the complicated interplay between tunnel magnetoresistance (TMR) ratio and the product of resistance and junction area (RA). An intricate connection exists between TMR ratio, RA value and the bandgap and crystal structure of the barrier, a connection that must be unravelled to optimise device performance and enable further applications to be developed. Here, we demonstrate a novel method to tailor the bandgap of an ultrathin, epitaxial Zn-doped MgO tunnel barrier with rocksalt structure. This structure is attractive due to its good ?1 spin filtering effect, and we show that MTJs based on tunable MgZnO barriers allow effective balancing of TMR ratio and RA value. In this way spin-dependent transport properties can be controlled, a key challenge for the development of spintronic devices.

  18. Full electrical control of Charge and Spin conductance through Interferometry of Edge States in Topological Insulators

    E-print Network

    Fabrizio Dolcini

    2011-05-13

    We investigate electron interferometry of edge states in Topological Insulators. We show that, when inter-boundary coupling is induced at two quantum point contacts of a four terminal setup, both Fabry-P\\'erot-like and Aharonov-Bohm-like loop processes arise. These underlying interference effects lead to a full electrically controllable system, where the magnitude of charge and spin linear conductances can be tuned by gate voltages, without applying magnetic fields. In particular we find that, under appropriate conditions, inter-boundary coupling can lead to negative values of the conductance. Furthermore, the setup also allows to selectively generate pure charge or pure spin currents, by choosing the voltage bias configuration.

  19. Electron spin resonance of defects in single crystal and thin films of tungsten trioxide

    Microsoft Academic Search

    S. K. Deb

    1977-01-01

    The ESR spectra of single crystal and amorphous thin films of WOâ have been measured in the temperature range 77--300 °K. In the case of single crystal the observed resonance lines were identified as due to Mo\\/sup 5 +\\/ ions. The observed values are: g\\/sub I\\/ = 1.776, g\\/sub II\\/ = 1.796, and g\\/sub III\\/ = 1.833 and the hyperfine

  20. Highly optimized simulations on single- and multi-GPU systems of 3D Ising spin glass

    E-print Network

    Lulli, Matteo; Parisi, Giorgio

    2014-01-01

    We present a highly optimized implementation of a Monte Carlo (MC) simulator for the three-dimensional Ising spin-glass model with bimodal disorder, i.e., the 3D Edwards-Anderson model running on CUDA enabled GPUs. Multi-GPU systems exchange data by means of the Message Passing Interface (MPI). The chosen MC dynamics is the classic Metropolis one, which is purely dissipative, since the aim was the study of the critical off-equilibrium relaxation of the system. We focused on the following issues: i) the implementation of efficient access patterns for nearest neighbours in a cubic stencil and for lagged-Fibonacci-like pseudo-Random Numbers Generators (PRNGs); ii) a novel implementation of the asynchronous multispin-coding Metropolis MC step allowing to store one spin per bit and iii) a multi-GPU version based on a combination of MPI and CUDA streams. We highlight how cubic stencils and PRNGs are two subjects of very general interest because of their widespread use in many simulation codes. Our code best perform...