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1

Coherent Control of a Single 29Si Nuclear Spin Qubit  

NASA Astrophysics Data System (ADS)

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 semiconductor materials, the spin-bearing nuclei are sufficiently rare that it is possible to identify and control individual host nuclear spins. This Letter presents the first experimental detection and manipulation of a single 29Si nuclear spin. The quantum nondemolition single-shot readout of the spin is demonstrated, and a Hahn echo measurement reveals a coherence time of T2=6.3 (7 ) ms —in excellent agreement with bulk experiments. Atomistic modeling combined with extracted experimental parameters provides possible lattice sites for the 29Si atom under investigation. These results demonstrate that single 29Si nuclear spins could serve as a valuable resource in a silicon spin-based quantum computer.

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

2014-12-01

2

Nuclear magnetic resonance spectroscopy with single spin sensitivity  

NASA Astrophysics Data System (ADS)

Nuclear magnetic resonance spectroscopy and magnetic resonance imaging at the ultimate sensitivity limit of single molecules or single nuclear spins requires fundamentally new detection strategies. The strong coupling regime, when interaction between sensor and sample spins dominates all other interactions, is one such strategy. In this regime, classically forbidden detection of completely unpolarized nuclei is allowed, going beyond statistical fluctuations in magnetization. Here we realize strong coupling between an atomic (nitrogen-vacancy) sensor and sample nuclei to perform nuclear magnetic resonance on four 29Si spins. We exploit the field gradient created by the diamond atomic sensor, in concert with compressed sensing, to realize imaging protocols, enabling individual nuclei to be located with Angstrom precision. The achieved signal-to-noise ratio under ambient conditions allows single nuclear spin sensitivity to be achieved within seconds.

Müller, C.; Kong, X.; Cai, J.-M.; Melentijevi?, K.; Stacey, A.; Markham, M.; Twitchen, D.; Isoya, J.; Pezzagna, S.; Meijer, J.; Du, J. F.; Plenio, M. B.; Naydenov, B.; McGuinness, L. P.; Jelezko, F.

2014-08-01

3

Nuclear magnetic resonance spectroscopy with single spin sensitivity  

PubMed Central

Nuclear magnetic resonance spectroscopy and magnetic resonance imaging at the ultimate sensitivity limit of single molecules or single nuclear spins requires fundamentally new detection strategies. The strong coupling regime, when interaction between sensor and sample spins dominates all other interactions, is one such strategy. In this regime, classically forbidden detection of completely unpolarized nuclei is allowed, going beyond statistical fluctuations in magnetization. Here we realize strong coupling between an atomic (nitrogen–vacancy) sensor and sample nuclei to perform nuclear magnetic resonance on four 29Si spins. We exploit the field gradient created by the diamond atomic sensor, in concert with compressed sensing, to realize imaging protocols, enabling individual nuclei to be located with Angstrom precision. The achieved signal-to-noise ratio under ambient conditions allows single nuclear spin sensitivity to be achieved within seconds. PMID:25146503

Müller, C.; Kong, X.; Cai, J.-M.; Melentijevi?, K.; Stacey, A.; Markham, M.; Twitchen, D.; Isoya, J.; Pezzagna, S.; Meijer, J.; Du, J. F.; Plenio, M. B.; Naydenov, B.; McGuinness, L. P.; Jelezko, F.

2014-01-01

4

Single shot NMR on single, dark nuclear spins  

E-print Network

The electron and nuclear spins associated with the nitrogen-vacancy (NV) center in diamond are supposed to be building blocks for quantum computing devices and nanometer scale magnetometry operating under ambient conditions. For every such building block precise knowledge of the involved quantum states is crucial. Especially for solid state systems the corresponding hilbert space can be large. Here, we experimentally show that under usual operating conditions the NV color center exists in an equilibrium of two charge states (i.e. 70% in the usually used negative (NV-) and 30% in the neutral one (NV0)). Projective quantum non-demolition measurement of the nitrogen nuclear spin enables the detection even of the additional, optically inactive state. It turns out that the nuclear spin can be coherently driven also in NV0. However, its T1 ~ 90 ms and T2 ~ 6micro-s times are much shorter than in NV-, supposedly because of the dynamic Jahn-Teller effect.

Waldherr, G; Steiner, M; Neumann, P; Gali, A; Jelezko, F; Wrachtrup, J

2010-01-01

5

Coherence of single spins coupled to a nuclear spin bath of varying density  

E-print Network

The dynamics of single electron and nuclear spins in a diamond lattice with different 13C nuclear spin concentration is investigated. It is shown that coherent control of up to three individual nuclei in a dense nuclear spin cluster is feasible. The free induction decays of nuclear spin Bell states and single nuclear coherences among 13C nuclear spins are compared and analyzed. Reduction of a free induction decay time T2* and a coherence time T2 upon increase of nuclear spin concentration has been found. For diamond material with depleted concentration of nuclear spin, T2* as long as 30 microseconds and T2 of up to 1.8 ms for the electron spin has been observed. The 13C concentration dependence of T2* is explained by Fermi contact and dipolar interactions with nuclei in the lattice. It has been found that T2 decreases approximately as 1/n, where n is 13C concentration, as expected for an electron spin interacting with a nuclear spin bath.

N. Mizuochi; P. Neumann; F. Rempp; J. Beck; V. Jacques; P. Siyushev; K. Nakamura; D. Twitchen; H. Watanabe; S. Yamasaki; F. Jelezko; J. Wrachtrup

2009-05-05

6

Dynamic polarization of single nuclear spins by optical pumping of nitrogen-vacancy color centers in diamond at room temperature.  

PubMed

We report a versatile method to polarize single nuclear spins in diamond, based on optical pumping of a single nitrogen-vacancy (NV) defect and mediated by a level anticrossing in its excited state. A nuclear-spin polarization higher than 98% is achieved at room temperature for the 15N nuclear spin associated with the NV center, corresponding to microK effective nuclear-spin temperature. We then show simultaneous initialization of two nuclear spins in the vicinity of a NV defect. Such robust control of nuclear-spin states is a key ingredient for further scaling up of nuclear-spin based quantum registers in diamond. PMID:19257552

Jacques, V; Neumann, P; Beck, J; Markham, M; Twitchen, D; Meijer, J; Kaiser, F; Balasubramanian, G; Jelezko, F; Wrachtrup, J

2009-02-01

7

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

NASA Astrophysics Data System (ADS)

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.

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

8

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

E-print Network

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.

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

2004-09-12

9

Sensing and atomic-scale structure analysis of single nuclear spin clusters in diamond  

E-print Network

Single-molecule nuclear magnetic resonance (NMR) is a crown-jewel challenge in the field of magnetic resonance spectroscopy and has important applications in chemical analysis and in quantum computing. Recently, it becomes possible to tackle this grand challenge thanks to experimental advances in preserving quantum coherence of nitrogen-vacancy (NV) center spins in diamond as a sensitive probe and theoretical proposals on atomic-scale magnetometry via dynamical decoupling control. Through decoherence measurement of NV centers under dynamical decoupling control, sensing of single $^{13}\\textbf{C}$ at nanometer distance has been realized. Toward the ultimate goal of structure analysis of single molecules, it is highly desirable to directly measure the interactions within single nuclear spin clusters. Here we sensed a single $^{13}\\textbf{C}$-$^{13}\\textbf{C}$ nuclear spin dimer located about 1 nm from the NV center and characterized the interaction between the two nuclear spins, by measuring NV center spin decoherence under various dynamical decoupling control. From the measured interaction we derived the spatial configuration of the dimer with atomic-scale resolution. These results demonstrate that central spin decoherence under dynamical decoupling control is a feasible probe for NMR structure analysis of single molecules.

Fazhan Shi; Xi Kong; Pengfei Wang; Fei Kong; Nan Zhao; Ren-Bao Liu; Jiangfeng Du

2013-09-25

10

Dynamic polarization of single nuclear spins by optical pumping of NV color centers in diamond at room temperature  

E-print Network

We report a versatile method to efficiently polarize single nuclear spins in diamond, which is based on optical pumping of a single NV color center and mediated by a level-anti crossing in its excited state. A nuclear spin polarization higher than 98% is achieved at room temperature for the 15N nuclear spin associated to the NV center, corresponding to $\\mu$K effective nuclear spin temperature. We then show simultaneous deterministic initialization of two nuclear spins (13C and 15N) in close vicinity to a NV defect. Such robust control of nuclear spin states is a key ingredient for further scaling up of nuclear-spin based quantum registers in diamond.

V. Jacques; P. Neumann; J. Beck; M. Markham; D. Twitchen; J. Meijer; F. Kaiser; G. Balasubramanian; F. Jelezko; J. Wrachtrup

2009-02-10

11

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

SciTech Connect

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.

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

1988-05-13

12

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

NASA Astrophysics Data System (ADS)

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 N14 nuclear spin qubit intrinsic to a nitrogen-vacancy 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 ?s.

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

2014-07-01

13

Optical detection of anisotropic g-factor and nuclear spin polarization in a single CdTe quantum well  

NASA Astrophysics Data System (ADS)

Longitudinal and in-plane electron g-factors, and a nuclear spin polarization (NSP) have been evaluated precisely in a CdTe/Cd0.85Mg0.15Te single quantum well by using the time-resolved Kerr rotation and double lock-in detection techniques. Resident electron spin polarization (RESP) was formed via the negative trion formation and recombination, and RESP gave rise to NSP in an oblique magnetic field configuration. We observed the effective nuclear field of a few mT which was weak compared with that in III–V semiconductor nanostructures as expected, but the nuclear field can be converted to the maximal NSP of 12% in Faraday geometry.

Yan, Li-Ping; Kurosawa, Masahiro; Hsu, Wei-Ting; Chang, Wen-Hao; Adachi, Satoru

2015-03-01

14

-Supplementary Material -Electrical read-out of individual nuclear spin trajectories in a single-molecule magnet  

E-print Network

. Terbium Double-Decker 1 S3. Nuclear Spin Read-Out 2 S4. Quantum Tunnelling of Magnetization 3 S5. Quantum magnetic field sweeps in three dimensions at field sweep rates up to 0.2 T/s. S2. TERBIUM DOUBLE-DECKER We used a Terbium (III) bis-phthalocyanine single molecule magnet (SMM), which is a metal-organic com

15

High-spin nuclear spectroscopy  

SciTech Connect

High-spin spectroscopy is the study of the changes in nuclear structure, properties, and behavior with increasing angular momentum. It involves the complex interplay between collective and single-particle motion, between shape and deformation changes, particle alignments, and changes in the pairing correlations. A review of progress in theory, experimentation, and instrumentation in this field is given. (DWL)

Diamond, R.M.

1986-07-01

16

Single-atom spin qubits in silicon  

NASA Astrophysics Data System (ADS)

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 [1]. Projective readout of such qubits had proved challenging until single-shot measurement of a single donor electron spin was demonstrated [2] 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 [2], 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 [3]. 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. [4pt] [1] B.E. Kane, Nature 393, 133 (1998). [2] A. Morello et al., Nature 467, 687 (2010). [3] J.J. Pla et al., Nature 489, 541 (2012).

Dzurak, Andrew

2013-03-01

17

Nuclear spin circular dichroism  

SciTech Connect

Recent years have witnessed a growing interest in magneto-optic spectroscopy techniques that use nuclear magnetization as the source of the magnetic field. Here we present a formulation of magnetic circular dichroism (CD) due to magnetically polarized nuclei, nuclear spin-induced CD (NSCD), in molecules. The NSCD ellipticity and nuclear spin-induced optical rotation (NSOR) angle correspond to the real and imaginary parts, respectively, of (complex) quadratic response functions involving the dynamic second-order interaction of the electron system with the linearly polarized light beam, as well as the static magnetic hyperfine interaction. Using the complex polarization propagator framework, NSCD and NSOR signals are obtained at frequencies in the vicinity of optical excitations. Hartree-Fock and density-functional theory calculations on relatively small model systems, ethene, benzene, and 1,4-benzoquinone, demonstrate the feasibility of the method for obtaining relatively strong nuclear spin-induced ellipticity and optical rotation signals. Comparison of the proton and carbon-13 signals of ethanol reveals that these resonant phenomena facilitate chemical resolution between non-equivalent nuclei in magneto-optic spectra.

Vaara, Juha, E-mail: juha.vaara@iki.fi [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland)] [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland); Rizzo, Antonio [Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche (IPCF-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa (Italy)] [Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche (IPCF-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa (Italy); Kauczor, Joanna; Norman, Patrick [Department of Physics, Chemistry and Biology, Linköping University, S-58183 Linköping (Sweden)] [Department of Physics, Chemistry and Biology, Linköping University, S-58183 Linköping (Sweden); Coriani, Sonia, E-mail: coriani@units.it [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy)] [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy)

2014-04-07

18

Liquid-State Nuclear Spin Comagnetometers  

NASA Astrophysics Data System (ADS)

We discuss nuclear spin comagnetometers based on ultralow-field nuclear magnetic resonance in mixtures of miscible solvents, each rich in a different nuclear spin. In one version thereof, Larmor precession of protons and F19 nuclei in a mixture of thermally polarized pentane and hexafluorobenzene is monitored via a sensitive alkali-vapor magnetometer. We realize transverse relaxation times in excess of 20 s and suppression of magnetic field fluctuations by a factor of 3400. We estimate it should be possible to achieve single-shot sensitivity of about 5×10-9Hz, or about 5×10-11Hz in ?1 day of integration. In a second version, spin precession of protons and Xe129 nuclei in a mixture of pentane and hyperpolarized liquid xenon is monitored using superconducting quantum interference devices. Application to spin-gravity experiments, electric dipole moment experiments, and sensitive gyroscopes is discussed.

Ledbetter, M. P.; Pustelny, S.; Budker, D.; Romalis, M. V.; Blanchard, J. W.; Pines, A.

2012-06-01

19

Decoherence of coupled electron spins via nuclear spin dynamics in quantum dots  

NASA Astrophysics Data System (ADS)

In double quantum dots, the exchange interaction between two electron spins renormalizes the excitation energy of pair flips in the nuclear spin bath, which in turn modifies the non-Markovian bath dynamics. As the energy renormalization varies with the static Overhauser field mismatch between the quantum dots, the electron singlet-triplet decoherence resulting from the bath dynamics depends on sampling of nuclear spin states from an ensemble, leading to the transition from superexponential decoherence in single-sample dynamics to power-law decay under ensemble averaging. In contrast, the decoherence of a single electron spin in one dot is essentially the same for different choices of the nuclear spin configuration.

Yang, W.; Liu, R. B.

2008-02-01

20

Locking electron spins into resonance by electron-nuclear feedback  

NASA Astrophysics Data System (ADS)

All basic building blocks for spin-based quantum information processing using electron spins in GaAs quantum dots have recently been realized. Recent experiments have shown single-shot read-out of an individual spin [1], the implementation of the SWAP gate [2] and (magnetically induced) coherent single electron spin rotations [3]. However, the main drawback of using electron spins in a GaAs environment is the short spin coherence time, which is measured to be in the nanosecond range [2,4]. The source of this fast decoherence is the hyperfine interaction of the localized electron spin with the randomly fluctuating nuclear spins of the host lattice. The fluctuations of the nuclear spins have to be reduced to extend the electron spin coherence time. We therefore study the electron-nuclear spin interaction and use magnetically driven spin resonance to control the electron spin and indirectly manipulate the nuclear spins. We apply continuous microwave excitation to the electron spin and observe strong electron-nuclear feedback. One experimental signature of this feedback is the locking of the electron spin system into resonance with the microwaves. Once the electron spin is locked into resonance, this resonance condition remains fullfilled even when the external magnetic field or the microwave frequency is changed. This is due to dynamically build up nuclear polarizations (up to 500 mT) which generally counteract the external magnetic field. Locking of the electron spin system into resonance might indicate that the nuclear polarization exhibits stable configurations where fluctuations of the nuclear distribution are reduced [5]. [4pt] References [0pt] [1] J. M. Elzerman et al. , Nature 430, 431 (2004) [0pt] [2]. J. R. Petta et al., Science 309, 2180 (2005). [0pt] [3] F. H. L. Koppens et al., Nature 442, 766 (2006). [0pt] [4] F. H. L. Koppens et al., Phys. Rev. Lett. 100, 236802 (2008). [0pt] [5] J. Danon and Yu. V. Nazarov, private communication.

Nowack, Katja

2009-03-01

21

Robust control of individual nuclear spins in diamond  

E-print Network

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.

Benjamin Smeltzer; Jean McIntyre; Lilian Childress

2009-09-22

22

Nanoscale imaging magnetometry with single spins in diamond  

NASA Astrophysics Data System (ADS)

Single Nitrogen-Vacancy colour centers in diamond are gaining popularity because of its exceptional optical and spin properties. The single spin of the defect can be manipulated optically, providing a efficient way to entangle single electron spins and couple nuclear spins qubits in diamond.[1] Long spin coherence time of these single defects finds application as sensitive magnetic field probes. Using engineered diamond we can achieve ultrahigh sensitivity using which we will be able to detect a single external electron or nucelar spin.[2] Controlled creation of these color centers inside nanodiamonds offers diverse applications. By attaching these single spins to the tip of a scanning probe, we were able to perform sensitive scanning probe magnetometry at nanoscale.[3] Improving this device by using quantum grade diamond and synchronized NMR pulse sequences we would have the ability to perform nanoscale NMR/MRI of single molecules.[0pt] [1] Neumann, P. et al. Multipartite Entanglement Among Single Spins in Diamond. Science 320, 1326-1329 (2008).[0pt] [2] Maze, J. R. et al. Nanoscale magnetic sensing with an individual electronic spin in diamond. Nature 455, 644-647(2008).[0pt] [3] Balasubramanian, G. et al. Nanoscale imaging magnetometry with diamond spins under ambient conditions. Nature 455, 648-651(2008).

Balasubramanian, Gopalakrishnan; Tisler, Julia; Kolesov, Roman; Jelezko, Fedor; Wrachtrup, Joerg

2009-03-01

23

Single spin asymmetry in DVCS  

E-print Network

In the following note, we will present an estimation of the single spin asymmetry in deeply virtual Compton scattering (DVCS) which directly allows one to test predictions of the ratio of the imaginary part of the amplitude in DIS to DVCS, as well as access the skewed parton distributions at small $x$ in the DGLAP region. We find it to be large for the HERA kinematics to be accessible in forthcoming runs with polarized electrons.

A. Freund; M. Strikman

1999-06-01

24

Uncovering many-body correlations in nanoscale nuclear spin baths by central spin decoherence.  

PubMed

Central spin decoherence caused by nuclear spin baths is often a critical issue in various quantum computing schemes, and it has also been used for sensing single-nuclear spins. Recent theoretical studies suggest that central spin decoherence can act as a probe of many-body physics in spin baths; however, identification and detection of many-body correlations of nuclear spins in nanoscale systems are highly challenging. Here, taking a phosphorus donor electron spin in a (29)Si nuclear spin bath as our model system, we discover both theoretically and experimentally that many-body correlations in nanoscale nuclear spin baths produce identifiable signatures in decoherence of the central spin under multiple-pulse dynamical decoupling control. We demonstrate that under control by an odd or even number of pulses, the central spin decoherence is principally caused by second- or fourth-order nuclear spin correlations, respectively. This study marks an important step toward studying many-body physics using spin qubits. PMID:25205440

Ma, Wen-Long; Wolfowicz, Gary; Zhao, Nan; Li, Shu-Shen; Morton, John J L; Liu, Ren-Bao

2014-01-01

25

Uncovering many-body correlations in nanoscale nuclear spin baths by central spin decoherence  

PubMed Central

Central spin decoherence caused by nuclear spin baths is often a critical issue in various quantum computing schemes, and it has also been used for sensing single-nuclear spins. Recent theoretical studies suggest that central spin decoherence can act as a probe of many-body physics in spin baths; however, identification and detection of many-body correlations of nuclear spins in nanoscale systems are highly challenging. Here, taking a phosphorus donor electron spin in a 29Si nuclear spin bath as our model system, we discover both theoretically and experimentally that many-body correlations in nanoscale nuclear spin baths produce identifiable signatures in decoherence of the central spin under multiple-pulse dynamical decoupling control. We demonstrate that under control by an odd or even number of pulses, the central spin decoherence is principally caused by second- or fourth-order nuclear spin correlations, respectively. This study marks an important step toward studying many-body physics using spin qubits. PMID:25205440

Ma, Wen-Long; Wolfowicz, Gary; Zhao, Nan; Li, Shu-Shen; Morton, John J.L.; Liu, Ren-Bao

2014-01-01

26

Single-spin stochastic optical reconstruction microscopy.  

PubMed

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

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

2014-10-14

27

Single spin stochastic optical reconstruction microscopy  

E-print Network

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 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.

Matthias Pfender; Nabeel Aslam; Gerald Waldherr; Jörg Wrachtrup

2014-04-05

28

Single-spin stochastic optical reconstruction microscopy  

PubMed Central

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

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

2014-01-01

29

Suppression of nuclear spin diffusion at a GaAs/AlGaAs interface measured with a single quantum dot nano-probe  

E-print Network

Nuclear spin polarization dynamics are measured in optically pumped individual GaAs/AlGaAs interface quantum dots by detecting the time-dependence of the Overhauser shift in photoluminescence (PL) spectra. Long nuclear polarization decay times of ~ 1 minute have been found indicating inefficient nuclear spin diffusion from the GaAs dot into the surrounding AlGaAs matrix in externally applied magnetic field. A spin diffusion coefficient two orders lower than that previously found in bulk GaAs is deduced.

A. E. Nikolaenko; E. A. Chekhovich; M. N. Makhonin; I. W. Drouzas; A. B. Vankov; J. Skiba-Szymanska; M. S. Skolnick; P. Senellart; A. Lemaitre; A. I. Tartakovskii

2009-01-15

30

Single-spin measurement using spin orbital entanglement  

NASA Astrophysics Data System (ADS)

Single-spin measurement represents a major challenge for spin-based quantum computation. In this paper, we propose a new method for measuring the spin of a single electron confined in a quantum dot (QD). Our strategy is based on entangling (using unitary gates) the spin and orbital degrees of freedom. An 'orbital qubit', defined by a second, empty QD, is used as an ancilla and is prepared in a known initial state. Measuring the orbital qubit will reveal the state of the (unknown) initial spin qubit, hence reducing the problem to the easier task of single charge measurement. Since spin-charge conversion is done with unit probability, single-shot measurement of an electronic spin can be, in principle, achieved. We evaluate the robustness of our method against various sources of error and discuss possible implementations.

Ionicioiu, Radu; Popescu, A. E.

2005-05-01

31

Electron spin decoherence in nuclear spin baths and dynamical decoupling  

SciTech Connect

We introduce the quantum theory of the electron spin decoherence in a nuclear spin bath and the dynamical decoupling approach for protecting the electron spin coherence. These theories are applied to various solid-state systems, such as radical spins in molecular crystals and NV centers in diamond.

Zhao, N.; Yang, W.; Ho, S. W.; Hu, J. L.; Wan, J. T. K.; Liu, R. B. [Department of Physics, Chinese University of Hong Kong, Shatin, New Territories (Hong Kong)

2011-12-23

32

Electron Spin Dephasing and Decoherence by Interaction with Nuclear Spins in Self-Assembled Quantum Dots  

NASA Technical Reports Server (NTRS)

Electron spin dephasing and decoherence by its interaction with nuclear spins in self-assembled quantum dots are investigated in the framework of the empirical tight-binding model. Electron spin dephasing in an ensemble of dots is induced by the inhomogeneous precession frequencies of the electron among dots, while electron spin decoherence in a single dot arises from the inhomogeneous precession frequencies of nuclear spins in the dot. For In(x)Ga(1-x) As self-assembled dots containing 30000 nuclei, the dephasing and decoherence times are predicted to be on the order of 100 ps and 1 (micro)s.

Lee, Seungwon; vonAllmen, Paul; Oyafuso, Fabiano; Klimeck, Gerhard; Whale, K. Birgitta

2004-01-01

33

Control of single spin in Markovian environment  

E-print Network

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 ...

Yuan, Haidong

34

Nuclear spin pair coherence in diamond for atomic scale magnetometry  

E-print Network

The nitrogen-vacancy (NV) centre, as a promising candidate solid state system of quantum information processing, its electron spin coherence is influenced by the magnetic field fluctuations due to the local environment. In pure diamonds, the environment consists of hundreds of C-13 nuclear spins randomly spreading in several nanometers range forming a spin bath. Controlling and prolonging the electron spin coherence under the influence of spin bath are challenging tasks for the quantum information processing. On the other hand, for a given bath distribution, many of its characters are encoded in the electron spin coherence. So it is natural to ask the question: is it possible to 'decode' the electron spin coherence, and extract the information about the bath structures? Here we show that, among hundreds of C-13 bath spins, there exist strong coupling clusters, which give rise to the millisecond oscillations of the electron spin coherence. By analyzing these oscillation features, the key properties of the coherent nuclear spin clusters, such as positions, orientations, and coupling strengths, could be uniquely identified. This addressability of the few-nuclear-spin cluster extends the feasibility of using the nuclear spins in diamond as qubits in quantum computing. Furthermore, it provides a novel prototype of single-electron spin based, high-resolution and ultra-sensitive detector for the chemical and biological applications.

Nan Zhao; Jian-Liang Hu; Sai-Wah Ho; Tsz-Kai Wen; R. B. Liu

2010-03-23

35

Single-shot readout of an electron spin in silicon.  

PubMed

The size of silicon transistors used in microelectronic devices is shrinking to the level at which quantum effects become important. Although this presents a significant challenge for the further scaling of microprocessors, it provides the potential for radical innovations in the form of spin-based quantum computers and spintronic devices. An electron spin in silicon can represent a well-isolated quantum bit with long coherence times because of the weak spin-orbit coupling and the possibility of eliminating nuclear spins from the bulk crystal. However, the control of single electrons in silicon has proved challenging, and so far the observation and manipulation of a single spin has been impossible. Here we report the demonstration of single-shot, time-resolved readout of an electron spin in silicon. This has been performed in a device consisting of implanted phosphorus donors coupled to a metal-oxide-semiconductor single-electron transistor-compatible with current microelectronic technology. We observed a spin lifetime of ?6?seconds at a magnetic field of 1.5?tesla, and achieved a spin readout fidelity better than 90 per cent. High-fidelity single-shot spin readout in silicon opens the way to the development of a new generation of quantum computing and spintronic devices, built using the most important material in the semiconductor industry. PMID:20877281

Morello, Andrea; Pla, Jarryd J; Zwanenburg, Floris A; Chan, Kok W; Tan, Kuan Y; Huebl, Hans; Möttönen, Mikko; Nugroho, Christopher D; Yang, Changyi; van Donkelaar, Jessica A; Alves, Andrew D C; Jamieson, David N; Escott, Christopher C; Hollenberg, Lloyd C L; Clark, Robert G; Dzurak, Andrew S

2010-10-01

36

Nuclear quadrupole spin-lattice relaxation in Bi{sub 4}Ge{sub 3}O{sub 12} single crystals doped with atoms of d or f elements. Crystal field effects in compounds exhibiting anomalous magnetic properties  

SciTech Connect

The nuclear quadrupole spin-lattice relaxation was studied in the range 4.2-300 K for single crystals of Bi{sub 4}Ge{sub 3}O{sub 12} doped with minor amounts (the tenth fractions of mol%) of paramagnetic atoms of Cr, Nd, and Gd. Unusual spin dynamic features were recently found for these crystals at room temperature: a dramatic (up to 8-fold) increase in the effective nuclear quadrupole spin-spin relaxation time T{sub 2}* occurred upon doping the pure Bi{sub 4}Ge{sub 3}O{sub 12} sample. Unlike T{sub 2}*, the effective spin-lattice relaxation time T{sub 1}* at room temperature differs insignificantly for both doped and pure samples. But at lower temperatures, the samples exhibit considerably different behavior of the spin-lattice relaxation with temperature, which is caused by different contributions to the relaxation process of the dopant paramagnetic atoms. The distinctive maximum in the temperature dependence of the spin-lattice relaxation time for the Nd-doped crystal is shown to result from the crystal electric field effects.

Orlov, V. G., E-mail: orlov@mbslab.kiae.ru; Sergeev, G. S. [Russian Research Center 'Kurchatov Institute' (Russian Federation); Asaji, Tetsuo [Nihon University, Department of Chemistry, College of Humanities and Sciences (Japan); Kravchenko, E. A. [Russian Academy of Sciences, Institute of General and Inorganic Chemistry (Russian Federation); Kargin, Yu. F. [Russian Academy of Sciences, State Institute of Metallurgy and Material Science (Russian Federation)

2010-02-15

37

Coherent properties of single rare-earth spin qubits  

E-print Network

Rare-earth-doped crystals are excellent hardware for quantum storage of optical information. Additional functionality of these materials is added by their waveguiding properties allowing for on-chip photonic networks. However, detection and coherent properties of rare-earth single-spin qubits have not been demonstrated so far. Here, we present experimental results on high-fidelity optical initialization, effcient coherent manipulation, and optical readout of a single electron spin of Ce$^{3+}$ ion in a YAG crystal. Under dynamic decoupling, spin coherence lifetime reaches $T_2$=2 ms and is almost limited by the measured spin-lattice relaxation time $T_1$=3.8 ms. Strong hyperfine coupling to aluminium nuclear spins suggests that cerium electron spins can be exploited as an interface between photons and long-lived nuclear spin memory. Combined with high brightness of Ce$^{3+}$ emission and a possibility of creating photonic circuits out of the host material, this makes cerium spins an interesting option for integrated quantum photonics.

P. Siyushev; K. Xia; R. Reuter; M. Jamali; N. Zhao; N. Yang; C. Duan; N. Kukharchyk; A. D. Wieck; R. Kolesov; J. Wrachtrup

2014-05-20

38

Submillisecond Hyperpolarization of Nuclear Spins in Silicon  

NASA Astrophysics Data System (ADS)

In this Letter, we devise a fast and effective nuclear spin hyperpolarization scheme, which is, in principle, magnetic field independent. We use this scheme to experimentally demonstrate polarizations of up to 66% for phosphorus donor nuclear spins in bulk silicon, which are created within less than 100 ? s in a magnetic field of 0.35 T at a temperature of 5 K. The polarization scheme is based on a spin-dependent recombination process via weakly coupled spin pairs, for which the recombination time constant strongly depends on the relative orientation of the two spins. We further use this scheme to measure the nuclear spin relaxation time and find a value of ˜100 ms under illumination, in good agreement with the value calculated for nuclear spin flips induced by repeated ionization and deionization processes.

Hoehne, Felix; Dreher, Lukas; Franke, David P.; Stutzmann, Martin; Vlasenko, Leonid S.; Itoh, Kohei M.; Brandt, Martin S.

2015-03-01

39

Submillisecond hyperpolarization of nuclear spins in silicon.  

PubMed

In this Letter, we devise a fast and effective nuclear spin hyperpolarization scheme, which is, in principle, magnetic field independent. We use this scheme to experimentally demonstrate polarizations of up to 66% for phosphorus donor nuclear spins in bulk silicon, which are created within less than 100???s in a magnetic field of 0.35 T at a temperature of 5 K. The polarization scheme is based on a spin-dependent recombination process via weakly coupled spin pairs, for which the recombination time constant strongly depends on the relative orientation of the two spins. We further use this scheme to measure the nuclear spin relaxation time and find a value of ?100??ms under illumination, in good agreement with the value calculated for nuclear spin flips induced by repeated ionization and deionization processes. PMID:25839308

Hoehne, Felix; Dreher, Lukas; Franke, David P; Stutzmann, Martin; Vlasenko, Leonid S; Itoh, Kohei M; Brandt, Martin S

2015-03-20

40

Nuclear spin qubits in a trapped-ion quantum computer  

E-print Network

Physical systems must fulfill a number of conditions to qualify as useful quantum bits (qubits) for quantum information processing, including ease of manipulation, long decoherence times, and high fidelity readout operations. Since these conditions are hard to satisfy with a single system, it may be necessary to combine different degrees of freedom. Here we discuss a possible system, based on electronic and nuclear spin degrees of freedom in trapped ions. The nuclear spin yields long decoherence times, while the electronic spin, in a magnetic field gradient, provides efficient manipulation, and the optical transitions of the ions assure a selective and efficient initialization and readout.

M. Feng; Y. Y. Xu; F. Zhou; D. Suter

2009-04-26

41

Spin effects in single-electron transistors  

E-print Network

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 ...

Granger, Ghislain

2005-01-01

42

Liquid-state nuclear spin comagnetometers  

NASA Astrophysics Data System (ADS)

We discuss liquid-state nuclear spin comagnetometers based on mixtures of mutually miscible solvents, each rich in a different nuclear spin. In one version thereof, thermally polarized ^1H and ^19F nuclear spins in a mixture of pentane and hexafluorobenzene are monitored in 1 mG fields using alkali-vapor magnetometers. In a second version, ^1H and ^129Xe spins in a mixture of pentane and hyperpolarized liquid xenon are monitored with a superconducting quantum interference device. In the former case, we show that magnetic field fluctuations can be suppressed by a factor of about 3400 and that frequency resolution of about 5x10-11 Hz may be realized in roughly one day of integration. We discuss the application of liquid-state nuclear spin comagnetometers to precision measurements such as a search for spin-gravity coupling or a permanent electric dipole moment, as well as to sensitive gyroscopes.

Ledbetter, Micah; Pustelny, Szymon; Budker, Dmitry; Romalis, Michael; Blanchard, John; Pines, Alexander

2012-06-01

43

Nanomechanical readout of a single spin  

NASA Astrophysics Data System (ADS)

The spin of a single electron in a suspended carbon nanotube can be read out by using its coupling to the nanomechanical motion of the nanotube. To show this, we consider a single electron confined within a quantum dot formed by the suspended carbon nanotube. The spin-orbit interaction induces a coupling between the spin and one of the bending modes of the suspended part of the nanotube. We calculate the response of the system to pulsed external driving of the mechanical motion using a Jaynes-Cummings model. To account for resonator damping, we solve a quantum master equation, with parameters comparable to those used in recent experiments, and show how information about the spin state of the system can be acquired by measuring the mechanical motion of the nanotube. The latter can be detected by observing the current through a nearby charge sensor.

Struck, Philipp R.; Wang, Heng; Burkard, Guido

2014-01-01

44

Single spin asymmetries in electroproduction at CLAS  

SciTech Connect

We present measurements of spin asymmetries in semi-inclusive processes in hard scattering kinematics using a 5.7 GeV electron beam and the CEBAF Large Acceptance Spectrometer (CLAS) at JLab. Scattering of longitudinally polarized electrons of an unpolarized liquid-hydrogen and off a polarized NH{sub 3} targets was studied over a wide range of kinematics. Non-zero single-beam and single-target spin asymmetries have been observed in semi-inclusive pion production in hard-scattering kinematics (Q{sup 2} > 1.2 GeV{sup 2}, W{sup 4} > 4 GeV{sup 2}). Systematic studies of factorization of x and z dependences have been done for different spin-dependent and spin-independent observables. No significant x/z dependence has been observed within statistical uncertainties, which is consistent with factorization of hard scattering and fragmentation processes.

Harut Avakian; Latifa Elouadrhiri

2004-06-02

45

Polarization of nuclear spins by a cold nanoscale resonator  

SciTech Connect

A cold nanoscale resonator coupled to a system of nuclear spins can induce spin relaxation. In the low-temperature limit where spin-lattice interactions are ''frozen out,'' spontaneous emission by nuclear spins into a resonant mechanical mode can become the dominant mechanism for cooling the spins to thermal equilibrium with their environment. We provide a theoretical framework for the study of resonator-induced cooling of nuclear spins in this low-temperature regime. Relaxation equations are derived from first principles, in the limit where energy donated by the spins to the resonator is quickly dissipated into the cold bath that damps it. A physical interpretation of the processes contributing to spin polarization is given. For a system of spins that have identical couplings to the resonator, the interaction Hamiltonian conserves spin angular momentum, and the resonator cannot relax the spins to thermal equilibrium unless this symmetry is broken by the spin Hamiltonian. The mechanism by which such a spin system becomes ''trapped'' away from thermal equilibrium can be visualized using a semiclassical model, which shows how an indirect spin-spin interaction arises from the coupling of multiple spins to one resonator. The internal spin Hamiltonian can affect the polarization process in two ways: (1) By modifying the structure of the spin-spin correlations in the energy eigenstates, and (2) by splitting the degeneracy within a manifold of energy eigenstates, so that zero-frequency off-diagonal terms in the density matrix are converted to oscillating coherences. Shifting the frequencies of these coherences sufficiently far from zero suppresses the development of resonator-induced correlations within the manifold during polarization from a totally disordered state. Modification of the spin-spin correlations by means of either mechanism affects the strength of the fluctuating spin dipole that drives the resonator. In the case where product states can be chosen as energy eigenstates, spontaneous emission from eigenstate populations into the resonant mode can be interpreted as independent emission by individual spins, and the spins relax exponentially to thermal equilibrium if the development of resonator-induced correlations is suppressed. When the spin Hamiltonian includes a significant contribution from the homonuclear dipolar coupling, the energy eigenstates entail a correlation specific to the coupling network. Simulations of dipole-dipole coupled systems of up to five spins suggest that these systems contain weakly emitting eigenstates that can trap a fraction of the population for time periods >>100/R{sub 0}, where R{sub 0} is the rate constant for resonator-enhanced spontaneous emission by a single spin 1/2. Much of the polarization, however, relaxes with rates comparable to R{sub 0}. A distribution of characteristic high-field chemical shifts tends to increase the relaxation rates of weakly emitting states, enabling transitions to states that can quickly relax to thermal equilibrium. The theoretical framework presented in this paper is illustrated with discussions of spin polarization in the contexts of force-detected nuclear-magnetic-resonance spectroscopy and magnetic-resonance force microscopy.

Butler, Mark C.; Weitekamp, Daniel P. [A. A. Noyes Laboratory of Chemical Physics, California Institute of Technology, MC 127-72, Pasadena, California 91125 (United States)

2011-12-15

46

Probing the Dynamics of a Nuclear Spin Bath in Diamond through Time-Resolved Central Spin Magnetometry  

NASA Astrophysics Data System (ADS)

Using fast electron spin resonance spectroscopy of a single nitrogen-vacancy defect in diamond, we demonstrate real-time readout of the Overhauser field produced by its nuclear spin environment under ambient conditions. These measurements enable narrowing the Overhauser field distribution by postselection, corresponding to a conditional preparation of the nuclear spin bath. Correlations of the Overhauser field fluctuations are quantitatively inferred by analyzing the Allan deviation over consecutive measurements. This method allows us to extract the dynamics of weakly coupled nuclear spins of the reservoir.

Dréau, A.; Jamonneau, P.; Gazzano, O.; Kosen, S.; Roch, J.-F.; Maze, J. R.; Jacques, V.

2014-09-01

47

Single-proton spin detection by diamond magnetometry.  

PubMed

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

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

2014-10-16

48

Room temperature entanglement between distant single spins in diamond  

E-print Network

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.

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

2012-12-12

49

Nuclear spin conversion in diatomic molecules  

SciTech Connect

A mechanism of the internal interaction in dimers that mixes different nuclear spin modifications has been proposed. It has been shown that the intramolecular current associated with transitions between electronic terms of different parities can generate different magnetic fields on nuclei, leading to transitions between spin modifications and to the corresponding changes in rotational states. In the framework of the known quantum relaxation process, this interaction initiates irreversible conversion of nuclear spin modifications. The estimated conversion rate for nitrogen at atmospheric pressure is quite high (10{sup -3}-10{sup -5} s{sup -1})

Il'ichev, L. V., E-mail: leonid@iae.nsk.su; Shalagin, A. M. [Russian Academy of Sciences, Institute of Automation and Electrometry, Siberian Branch (Russian Federation)] [Russian Academy of Sciences, Institute of Automation and Electrometry, Siberian Branch (Russian Federation)

2013-07-15

50

Spin excitations in di-nuclear systems  

SciTech Connect

The spin excitations of products from two-body reactions have two sources: transfer of orbital motion into intrinsic spins via tangential friction and thermal excitations of di-nuclear spin modes. The relative importance of these two mechanisms is discussed for deep inelastic scattering, quasi-fission and spontaneous fission processes. The results of simple model calculations are compared to measured {gamma}-multiplicities in {sup 238}U induced quasi-fission reactions and it is concluded that the spin-excitation are only partially equilibrated during the interaction. 11 refs., 5 figs.

Back, B.B.

1990-01-01

51

Single-Spin Asymmetries and Transversity in QCD  

SciTech Connect

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.

Brodsky, S.J.; /SLAC

2005-12-14

52

Spin echo decay at low magnetic fields in a nuclear spin bath  

E-print Network

We investigate theoretically the spin echo signal of an electron localized in a quantum dot and interacting with a bath of nuclear spins. We consider the regime of very low magnetic fields (corresponding to fields as low as a militesla in realistic GaAs and InGaAs dots). We use both the exact numerical simulations and the analytical theory employing the effective pure dephasing Hamiltonian. The comparison shows that the latter approach describes very well the spin echo decay at magnetic fields larger than the typical Overhauser field, and that the timescale at which this theory works is larger than previously expected. The numerical simulations are also done for very low values of electron spin splitting at which the effective Hamiltonian based theory fails quantitatively. Interestingly, the qualitative difference in the spin echo decay between the cases of a homonuclear and a heteronuclear bath (i.e. bath containing nuclear isotopes having different Zeeman energies), predicted previously using the effective Hamiltonian approach, is still visible at very low fields outside the regime of applicability of the analytical theory. We have found that the spin echo signal for a homonuclear bath oscillates with a frequency corresponding to the Zeeman splitting of the single nuclear isotope present in the bath. The physics behind this feature is similar to that of the electron spin echo envelope modulation (ESEEM). While purely isotropic hyperfine interactions are present in our system, the tilting of the electron precession axis at low fields may explain this result.

L. Cywinski; V. V. Dobrovitski; S. Das Sarma

2010-07-23

53

Neutron single target spin asymmetries in SIDIS  

SciTech Connect

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.

Evaristo Cisbani

2010-04-01

54

Sensing electric fields using single diamond spins  

E-print Network

The ability to sensitively detect charges under ambient conditions would be a fascinating new tool benefitting a wide range of researchers across disciplines. However, most current techniques are limited to low-temperature methods like single-electron transistors (SET), single-electron electrostatic force microscopy and scanning tunnelling microscopy. Here we open up a new quantum metrology technique demonstrating precision electric field measurement using a single nitrogen-vacancy defect centre(NV) spin in diamond. An AC electric field sensitivity reaching ~ 140V/cm/\\surd Hz has been achieved. This corresponds to the electric field produced by a single elementary charge located at a distance of ~ 150 nm from our spin sensor with averaging for one second. By careful analysis of the electronic structure of the defect centre, we show how an applied magnetic field influences the electric field sensing properties. By this we demonstrate that diamond defect centre spins can be switched between electric and magnetic field sensing modes and identify suitable parameter ranges for both detector schemes. By combining magnetic and electric field sensitivity, nanoscale detection and ambient operation our study opens up new frontiers in imaging and sensing applications ranging from material science to bioimaging.

Florian Dolde; Helmut Fedder; Marcus W. Doherty; Tobias Nöbauer; Florian Rempp; Gopalakrishnan Balasubramanian; Thomas Wolf; Friedemann Reinhard; Lloyd C. L. Hollenberg; Fedor Jelezko; Jörg Wrachtrup

2011-03-17

55

The spin-temperature theory of dynamic nuclear polarization and nuclear spin-lattice relaxation  

NASA Technical Reports Server (NTRS)

A detailed derivation of the equations governing dynamic nuclear polarization (DNP) and nuclear spin lattice relaxation by use of the spin temperature theory has been carried to second order in a perturbation expansion of the density matrix. Nuclear spin diffusion in the rapid diffusion limit and the effects of the coupling of the electron dipole-dipole reservoir (EDDR) with the nuclear spins are incorporated. The complete expression for the dynamic nuclear polarization has been derived and then examined in detail for the limit of well resolved solid effect transitions. Exactly at the solid effect transition peaks, the conventional solid-effect DNP results are obtained, but with EDDR effects on the nuclear relaxation and DNP leakage factor included. Explicit EDDR contributions to DNP are discussed, and a new DNP effect is predicted.

Byvik, C. E.; Wollan, D. S.

1974-01-01

56

Single-crystal and powder electron-nuclear double resonance of RbCl:O-2: A comparison between the spin Hamiltonian parameters obtained from both experiments  

NASA Astrophysics Data System (ADS)

In this work a single-crystal ENDOR study of RbCl:O-2 is presented. The angular variation of two sets of 85Rb and 87Rb ENDOR transitions is investigated. The corresponding superhyperfine (SHF) and nuclear-quadrupole coupling tensors are determined. These ENDOR results can be explained only by assuming a monovacancy model, i.e., O-2 replacing a single Cl- ion. The linewidth of the EPR signals is shown to be determined by the Rb SHF interaction. The corresponding powder ENDOR study of RbCl:O-2 is also presented. The powder ENDOR spectra could be simulated using the single-crystal data. Finally, from this simulation procedure a fitting program is derived to obtain information from powder ENDOR spectra of analogous systems.

van Doorslaer, S.; Callens, F.; Maes, F.; Boesman, E.

1995-05-01

57

Dynamics of a mesoscopic nuclear spin ensemble interacting with an optically driven electron spin  

NASA Astrophysics Data System (ADS)

The ability to discriminate between simultaneously occurring noise sources in the local environment of semiconductor InGaAs quantum dots, such as electric and magnetic field fluctuations, is key to understanding their respective dynamics and their effect on quantum dot coherence properties. We present a discriminatory approach to all-optical sensing based on two-color resonance fluorescence of a quantum dot charged with a single electron. Our measurements show that local magnetic field fluctuations due to nuclear spins in the absence of an external magnetic field are described by two correlation times, both in the microsecond regime. The nuclear spin bath dynamics show a strong dependence on the strength of resonant probing, with correlation times increasing by a factor of 4 as the optical transition is saturated. We interpret the behavior as motional averaging of both the Knight field of the resident electron spin and the hyperfine-mediated nuclear spin-spin interaction due to optically induced electron spin flips.

Stanley, M. J.; Matthiesen, C.; Hansom, J.; Le Gall, C.; Schulte, C. H. H.; Clarke, E.; Atatüre, M.

2014-11-01

58

Dynamics of a mesoscopic nuclear spin ensemble interacting with an optically driven electron spin  

E-print Network

The ability to discriminate between simultaneously occurring noise sources in the local environment of semiconductor InGaAs quantum dots, such as electric and magnetic field fluctuations, is key to understanding their respective dynamics and their effect on quantum dot coherence properties. We present a discriminatory approach to all-optical sensing based on two-color resonance fluorescence of a quantum dot charged with a single electron. Our measurements show that local magnetic field fluctuations due to nuclear spins in the absence of an external magnetic field are described by two correlation times, both in the microsecond regime. The nuclear spin bath dynamics show a strong dependence on the strength of resonant probing, with correlation times increasing by a factor of four as the optical transition is saturated. We interpret the behavior as motional averaging of both the Knight field of the resident electron spin and the hyperfine-mediated nuclear spin-spin interaction due to optically-induced electron spin flips.

Megan J. Stanley; Clemens Matthiesen; Jack Hansom; Claire Le Gall; Carsten H. H. Schulte; Edmund Clarke; Mete Atatüre

2014-11-17

59

Collins Mechanism Contributions to Single Spin Asymmetry  

SciTech Connect

We present recent developments on the single transverse spin physics, in particular, the Collins mechanism contributions in various hadronic reactions, such as semi-inclusive hadron production in DIS process, azimuthal distribution of hadron in high energy jet in pp collisions. We will demonstrate that the transverse momentum dependent and collinear factorization approaches are consistent with each other in the description of the Collins effects in the semi-inclusive hadron production in DIS process.

Yuan,F.

2009-05-26

60

Collins Mechanism Contributions to Single Spin Asymmetry  

SciTech Connect

We present recent developments on the single transverse spin physics,in particular, the Collins mechanism contributions in various hadronic reactions,such as semi-inclusive hadron production in DIS process, azimuthal distributionof hadron in high energy jet in pp collisions. We will demonstrate thatthe transverse momentum dependent and collinear factorization approaches areconsistentwith each other in the description of the Collins effects in the semi-inclusivehadron production in DIS process.

Yuan, Feng

2009-09-11

61

Collins Mechanism Contributions to Single Spin Asymmetry  

SciTech Connect

We present recent developments on the single transverse spin physics, in particular, the Collins mechanism contributions in various hadronic reactions, such as semi-inclusive hadron production in DIS process, azimuthal distribution of hadron in high energy jet in pp collisions. We will demonstrate that the transverse momentum dependent and collinear factorization approaches are consistent with each other in the description of the Collins effects in the semi-inclusive hadron production in DIS process.

Yuan,F.

2009-05-25

62

Optical switching of nuclear spin-spin couplings in semiconductors.  

PubMed

Two-qubit operation is an essential part of quantum computation. However, solid-state nuclear magnetic resonance quantum computing has not been able to fully implement this functionality, because it requires a switchable inter-qubit coupling that controls the time evolutions of entanglements. Nuclear dipolar coupling is beneficial in that it is present whenever nuclear-spin qubits are close to each other, while it complicates two-qubit operation because the qubits must remain decoupled to prevent unwanted couplings. Here we introduce optically controllable internuclear coupling in semiconductors. The coupling strength can be adjusted externally through light power and even allows on/off switching. This feature provides a simple way of switching inter-qubit couplings in semiconductor-based quantum computers. In addition, its long reach compared with nuclear dipolar couplings allows a variety of options for arranging qubits, as they need not be next to each other to secure couplings. PMID:21730962

Goto, Atsushi; Ohki, Shinobu; Hashi, Kenjiro; Shimizu, Tadashi

2011-01-01

63

Optical switching of nuclear spin–spin couplings in semiconductors  

PubMed Central

Two-qubit operation is an essential part of quantum computation. However, solid-state nuclear magnetic resonance quantum computing has not been able to fully implement this functionality, because it requires a switchable inter-qubit coupling that controls the time evolutions of entanglements. Nuclear dipolar coupling is beneficial in that it is present whenever nuclear–spin qubits are close to each other, while it complicates two-qubit operation because the qubits must remain decoupled to prevent unwanted couplings. Here we introduce optically controllable internuclear coupling in semiconductors. The coupling strength can be adjusted externally through light power and even allows on/off switching. This feature provides a simple way of switching inter-qubit couplings in semiconductor-based quantum computers. In addition, its long reach compared with nuclear dipolar couplings allows a variety of options for arranging qubits, as they need not be next to each other to secure couplings. PMID:21730962

Goto, Atsushi; Ohki, Shinobu; Hashi, Kenjiro; Shimizu, Tadashi

2011-01-01

64

Quantum control and engineering of single spins in diamond  

NASA Astrophysics Data System (ADS)

The past two decades have seen intensive research efforts aimed at creating quantum technologies that leverage phenomena such as coherence and entanglement to achieve device functionalities surpassing those attainable with classical physics. While the range of applications for quantum devices is typically limited by their cryogenic operating temperatures, in recent years point defects in semiconductors have emerged as potential candidates for room temperature quantum technologies. In particular, the nitrogen vacancy (NV) center in diamond has gained prominence for the ability to measure and control its spin under ambient conditions and for its potential applications in magnetic sensing. Here we describe experiments that probe the thermal limits to the measurement and control of single NV centers to identify the origin of the system's unique temperature dependence and that define novel thermal sensing applications for single spins. We demonstrate the optical measurement and coherent control of the spin at temperatures exceeding 600 K and show that its addressability is eventually limited by thermal quenching of the optical spin readout. These measurements provide important information for the electronic structure responsible for the optical spin initialization and readout processes and, moreover, suggest that the coherence of the NV center's spin states could be harnessed for thermometry applications. To that end, we develop novel quantum control techniques that selectively probe thermally induced shifts in the spin resonance frequencies while minimizing the defect's interactions with nearby nuclear spins. We use these techniques to extend the NV center's spin coherence for thermometry by 45-fold to achieve thermal sensitivities approaching 10 mK Hz-1/2 . We show the versatility of these techniques by performing measurements in a range of magnetic environments and at temperatures as high as 500 K. Together with diamond's ideal thermal, mechanical, and chemical properties, these measurements suggest that NV center sensors could be employed in a diverse range of applications such as intracellular thermometry, microfuidic thermometry, and scanning thermal microscopy. Finally, while the development of NV center technologies is motivated by the desirable properties of isolated defects in bulk diamond, the realization of many of these technologies, such as those using the spin as a proximal sensor, require a means to control the placement of NV centers within the diamond lattice. We demonstrate a method to pattern defect formation on sub-100-nm length scales using ion implantation and electron beam lithography techniques. The ability to engineer large scale arrays of NV centers with this method holds promise for a variety of applications in quantum information science and nanoscale sensing.

Toyli, David M.

65

Nuclear spin effects in optical lattice clocks  

SciTech Connect

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

Boyd, Martin M.; Zelevinsky, Tanya; Ludlow, Andrew D.; Blatt, Sebastian; Zanon-Willette, Thomas; Foreman, Seth M.; Ye Jun [JILA, National Institute of Standards and Technology and University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309-0440 (United States)

2007-08-15

66

Nuclear spin physics in quantum dots: An optical investigation  

NASA Astrophysics Data System (ADS)

The mesoscopic spin system formed by the 104-106 nuclear spins in a semiconductor quantum dot offers a unique setting for the study of many-body spin physics in the condensed matter. The dynamics of this system and its coupling to electron spins is fundamentally different from its bulk counterpart or the case of individual atoms due to increased fluctuations that result from reduced dimensions. In recent years, the interest in studying quantum-dot nuclear spin systems and their coupling to confined electron spins has been further fueled by its importance for possible quantum information processing applications. The fascinating nonlinear (quantum) dynamics of the coupled electron-nuclear spin system is universal in quantum dot optics and transport. In this article, experimental work performed over the last decade in studying this mesoscopic, coupled electron-nuclear spin system is reviewed. Here a special focus is on how optical addressing of electron spins can be exploited to manipulate and read out the quantum-dot nuclei. Particularly exciting recent developments in applying optical techniques to efficiently establish nonzero mean nuclear spin polarizations and using them to reduce intrinsic nuclear spin fluctuations are discussed. Both results critically influence the preservation of electron-spin coherence in quantum dots. This overall recently gained understanding of the quantum-dot nuclear spin system could enable exciting new research avenues such as experimental observations of spontaneous spin ordering or nonclassical behavior of the nuclear spin bath.

Urbaszek, Bernhard; Marie, Xavier; Amand, Thierry; Krebs, Olivier; Voisin, Paul; Maletinsky, Patrick; Högele, Alexander; Imamoglu, Atac

2013-01-01

67

Electron Spin in Single Wall Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

We review aspects of electrical transport in metallic single wall carbon nanotubes (SWCNT) related to the spin of the conductance electrons. For large contact resistances, R ? h/2e2, a SWCNT exhibits Coulomb blockade, and transmission can only occur, when a gate voltage leads to an energy degeneracy for two different numbers of electrons in the SWCNT. The Coulomb blockade gate voltage change is directly proportional to the addition energy for single electron tunnelling. In certain ideal cases every second of the populated electronic states has a higher addition energy, indicating that two spindegenerate electrons are roomed at each orbital state. A low addition energy therefore corresponds to approaching an even number of electrons. The odd-even alternation can be checked in a magnetic field, since then the odd additional electron may enter in one of two Zeeman states. If the high resistance contact is a tunnel junction, the transmission reflects the density of states. This leads to a direct detection of the so-called Luttinger liquid state of the electrons. Ferromagnetic contacts to the SWCNT leads to a conductance which depends on the orientation of the magnetic domains in the contacts. The magnetoresistance effect can be much larger than expected from a simple spin-valve phenomenon. For any intermediate normal metal (Au) contact resistances, R ˜ h/2e2, the Coulomb blockade may still separate the single electron states in the SWCNT with odd and even numbers of electrons. However, at the lowest temperatures the transmission only shows Coulomb blockade for even number of electrons. In the situations with odd number of electrons a coherent tunnelling process dominates. This shortage of the blockade is rooted in the Kondo states formed in the two Au electrodes by exchange interaction due to the spin state in the SWCNT. This tunnelling process is a result of a net spin on the SWCNT and consequently a spin degeneracy. A triplet state is forced into degeneracy with the singlet state in a suitable magnetic field. The situation in a magnetic field is particularly simple in a SWCNT, in contrast to conventional quantum dots, because the tiny diameter of the SWCNT practically speaking precludes orbital effects.

Lindelof, P. E.; Borggreen, J.; Jensen, A.; Nygård, J.; Poulsen, P. R.

2003-10-01

68

Electron Spin in Single Wall Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

We review aspects of electrical transport in metallic single wall carbon nanotubes (SWCNT) related to the spin of the conductance electrons. For large contact resistances, R?h/2e2, a SWCNT exhibits Coulomb blockade, and transmission can only occur, when a gate voltage leads to an energy degeneracy for two different numbers of electrons in the SWCNT. The Coulomb blockade gate voltage change is directly proportional to the addition energy for single electron tunnelling. In certain ideal cases every second of the populated electronic states has a higher addition energy, indicating that two spindegenerate electrons are roomed at each orbital state. A low addition energy therefore corresponds to approaching an even number of electrons. The odd-even alternation can be checked in a magnetic field, since then the odd additional electron may enter in one of two Zeeman states. If the high resistance contact is a tunnel junction, the transmission reflects the density of states. This leads to a direct detection of the so-called Luttinger liquid state of the electrons. Ferromagnetic contacts to the SWCNT leads to a conductance which depends on the orientation of the magnetic domains in the contacts. The magnetoresistance effect can be much larger than expected from a simple spin-valve phenomenon. For any intermediate normal metal (Au) contact resistances, Rh/2e2, the Coulomb blockade may still separate the single electron states in the SWCNT with odd and even numbers of electrons. However, at the lowest temperatures the transmission only shows Coulomb blockade for even number of electrons. In the situations with odd number of electrons a coherent tunnelling process dominates. This shortage of the blockade is rooted in the Kondo states formed in the two Au electrodes by exchange interaction due to the spin state in the SWCNT. This tunnelling process is a result of a net spin on the SWCNT and consequently a spin degeneracy. A triplet state is forced into degeneracy with the singlet state in a suitable magnetic field. The situation in a magnetic field is particularly simple in a SWCNT, in contrast to conventional quantum dots, because the tiny diameter of the SWCNT practically speaking precludes orbital effects.

Lindelof, P. E.; Borggreen, J.; Jensen, A.; Nygård, J.; Poulsen, P. R.

69

Protein imaging. Single-protein spin resonance spectroscopy under ambient conditions.  

PubMed

Magnetic resonance is essential in revealing the structure and dynamics of biomolecules. However, measuring the magnetic resonance spectrum of single biomolecules has remained an elusive goal. We demonstrate the detection of the electron spin resonance signal from a single spin-labeled protein under ambient conditions. As a sensor, we use a single nitrogen vacancy center in bulk diamond in close proximity to the protein. We measure the orientation of the spin label at the protein and detect the impact of protein motion on the spin label dynamics. In addition, we coherently drive the spin at the protein, which is a prerequisite for studies involving polarization of nuclear spins of the protein or detailed structure analysis of the protein itself. PMID:25745170

Shi, Fazhan; Zhang, Qi; Wang, Pengfei; Sun, Hongbin; Wang, Jiarong; Rong, Xing; Chen, Ming; Ju, Chenyong; Reinhard, Friedemann; Chen, Hongwei; Wrachtrup, Jörg; Wang, Junfeng; Du, Jiangfeng

2015-03-01

70

Radio Frequency Scanning Tunneling Spectroscopy for Single-Molecule Spin Resonance  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

71

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

PubMed

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

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

2014-09-26

72

Single transverse spin asymmetry of forward neutrons  

NASA Astrophysics Data System (ADS)

We calculate the single transverse spin asymmetry AN(t), for inclusive neutron production in pp collisions at forward rapidities relative to the polarized proton in the energy range of RHIC. Absorptive corrections to the pion pole generate a relative phase between the spin-flip and nonflip amplitudes, leading to a transverse spin asymmetry which is found to be far too small to explain the magnitude of AN observed in the PHENIX experiment. A larger contribution, which does not vanish at high energies, comes from the interference of pion and a1-Reggeon exchanges. The unnatural parity of a1 guarantees a substantial phase shift, although the magnitude is strongly suppressed by the smallness of diffractive ?p?a1p cross section. We replace the Regge a1 pole by the Regge cut corresponding to the ?? exchange in the 1+S state. The production of such a state, which we treat as an effective pole a, forms a narrow peak in the 3? invariant mass distribution in diffractive ?p interactions. The cross section is large, so one can assume that this state saturates the spectral function of the axial current and we can determine its coupling to nucleons via the partially conserved axial-vector-current constraint Goldberger-Treiman relation and the second Weinberg sum rule. The numerical results of the parameter-free calculation of AN are in excellent agreement with the PHENIX data.

Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Iván; Soffer, J.

2011-12-01

73

Coherent single-spin source based on topological insulators  

NASA Astrophysics Data System (ADS)

We report on the injection of quantized pure spin current into quantum conductors. In particular, we propose an on-demand single-spin source generated by periodically varying the gate voltages of two quantum dots that are connected to a two-dimensional topological insulator via tunneling barriers. Due to the nature of the helical states of the topological insulator, one or several spin pairs can be pumped out per cycle giving rise to a pure quantized alternating spin current. Depending on the phase difference between two gate voltages, this device can serve as an on-demand single-spin emitter or single-charge emitter. Again, due to the helicity of the topological insulator, the single-spin emitter or charge emitter is dissipationless and immune to disorder. The proposed single-spin emitter can be an important building block of future spintronic devices.

Xing, Yanxia; Yang, Zhong-liu; Sun, Qing-feng; Wang, Jian

2014-08-01

74

Measuring mechanical motion with a single spin  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

75

Storing entanglement of nuclear spins via Uhrig dynamical decoupling  

SciTech Connect

Stroboscopic spin flips have already been shown to prolong the coherence times of quantum systems under noisy environments. Uhrig's dynamical decoupling scheme provides an optimal sequence for a quantum system interacting with a dephasing bath. Several experimental demonstrations have already verified the efficiency of such dynamical decoupling schemes in preserving single-qubit coherences. In this work we describe the experimental study of Uhrig's dynamical decoupling in preserving two-qubit entangled states using an ensemble of spin-1/2 nuclear pairs in solution state. We find that the performance of odd-order Uhrig sequences in preserving entanglement is superior to both even-order Uhrig sequences and periodic spin-flip sequences. We also find that there exists an optimal order of the Uhrig sequence in which a singlet state can be stored at high correlation for about 30 seconds.

Roy, Soumya Singha; Mahesh, T. S. [Indian Institute of Science Education and Research, Pune 411008 (India); Agarwal, G. S. [Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)

2011-06-15

76

Storing entanglement of nuclear spins via Uhrig Dynamical Decoupling  

E-print Network

Stroboscopic spin flips have already been shown to prolong the coherence times of quantum systems under noisy environments. Uhrig's dynamical decoupling scheme provides an optimal sequence for a quantum system interacting with a dephasing bath. Several experimental demonstrations have already verified the efficiency of such dynamical decoupling schemes in preserving single qubit coherences. In this work we describe the experimental study of Uhrig's dynamical decoupling in preserving two-qubit entangled states using an ensemble of spin-1/2 nuclear pairs in solution state. We find that the performance of odd-order Uhrig sequences in preserving entanglement is superior to both even-order Uhrig sequences and periodic spin-flip sequences. We also find that there exists an optimal length of the Uhrig sequence at which the decoherence time gets boosted from a few seconds to about 30 seconds.

Soumya Singha Roy; T. S. Mahesh; G. S. Agarwal

2011-10-07

77

NUCLEAR SPIN ISOSPIN RESPONSES FOR LOW-ENERGY NEUTRINOS  

E-print Network

NUCLEAR SPIN ISOSPIN RESPONSES FOR LOW-ENERGY NEUTRINOS Hiroyasu EJIRI Nuclear Physics Laboratory@rcnp.osaka-u.ac.jp (H. Ejiri). Physics Reports 338 (2000) 265}351 Nuclear spin isospin responses for low-energy Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka, 567 Japan. E-mail address: ejiri

Washington at Seattle, University of

78

Single-shot readout and microwave control of an electron spin in silicon  

NASA Astrophysics Data System (ADS)

The electron spin of a donor in silicon is an excellent candidate for a solid-state qubit. It is known to have very long coherence and relaxation times in bulk [1], and several architectures have been proposed to integrate donor spin qubits with classical silicon microelectronics [2]. Here we show the first experimental proof of single-shot readout of an electron spin in silicon. The device consists of implanted phosphorus donors, tunnel-coupled to a silicon Single-Electron Transistor (SET), where the SET island is used as a reservoir for spin-to-charge conversion [3]. The large charge transfer signals allow readout fidelity >90% with 3 ?s response time. By measuring the occurrence of excited spin states as a function of wait time, we find spin lifetimes (T1) up to ˜ 6 s at B = 1.5 T, and a magnetic-field dependence T1-1 B^5 consistent with that of phosphorus donors in silicon [4]. In a subsequent experiment we have integrated the single-shot spin readout device with an on-chip microwave transmission line for coherent control of the electron spin. We have detected the spin resonance of a single electron, and observed two hyperfine-split resonance lines, consistent with Stark-shifted coupling to the ^31P nuclear spin. Further experiments are underway to demonstrate coherent spin control and observe Rabi oscillations. This demonstrates the microwave control of a single spin, combined -- for the first time in the same experiment -- with electrically detected single-shot spin readout. [1] A. M. Tyryshkin et al., Phys. Rev. B 68, 193207 (2003). [2] L. C. L. Hollenberg et al., Phys. Rev. B. 74, 045311 (2006). [3] A. Morello et al., Phys. Rev. B 80, 081307(R) (2009). [4] A. Morello et al., Nature 467, 687 (2010).

Morello, Andrea

2011-03-01

79

Spin responses in correlated nuclear matter  

NASA Astrophysics Data System (ADS)

Correlated Basis Function theory is used to compute the longitudinal and transverse dynamical spin responses in nuclear matter. The effect of the tensor correlations, induced by realistic nucleon-nucleon interactions, is studied in the isoscalar and isovector channels. Their inclusion brings the values of the ratio between the longitudinal and transverse responses close to unity and to the experimental estimates in medium-heavy nuclei.

Fabrocini, Adelchi

1994-02-01

80

Nanoscale magnetic imaging of a single electron spin under ambient conditions  

E-print Network

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 measuring 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 a single electron spin under ambient conditions using a scanning nitrogen-vacancy (NV) magnetometer. Real-space, quantitative magnetic-field images are obtained by deterministically scanning our NV magnetometer 50 nanometers above a target electron spin, while measuring the local magnetic field using dynamically decoupled magnetometry protocols. This single-spin detection capability could enable single-spin magnetic resonance imaging of electron spins on the nano- and atomic scales and opens the door for unique applications such as mechanical quantum state transfer.

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

2012-09-02

81

Atomic-Scale Nuclear Spin Imaging Using Quantum-Assisted Sensors in Diamond  

NASA Astrophysics Data System (ADS)

Nuclear spin imaging at the atomic level is essential for the understanding of fundamental biological phenomena and for applications such as drug discovery. The advent of novel nanoscale sensors promises to achieve the long-standing goal of single-protein, high spatial-resolution structure determination under ambient conditions. In particular, quantum sensors based on the spin-dependent photoluminescence of nitrogen-vacancy (NV) centers in diamond have recently been used to detect nanoscale ensembles of external nuclear spins. While NV sensitivity is approaching single-spin levels, extracting relevant information from a very complex structure is a further challenge since it requires not only the ability to sense the magnetic field of an isolated nuclear spin but also to achieve atomic-scale spatial resolution. Here, we propose a method that, by exploiting the coupling of the NV center to an intrinsic quantum memory associated with the nitrogen nuclear spin, can reach a tenfold improvement in spatial resolution, down to atomic scales. The spatial resolution enhancement is achieved through coherent control of the sensor spin, which creates a dynamic frequency filter selecting only a few nuclear spins at a time. We propose and analyze a protocol that would allow not only sensing individual spins in a complex biomolecule, but also unraveling couplings among them, thus elucidating local characteristics of the molecule structure.

Ajoy, A.; Bissbort, U.; Lukin, M. D.; Walsworth, R. L.; Cappellaro, P.

2015-01-01

82

Atomic-scale nuclear spin imaging using quantum-assisted sensors in diamond  

E-print Network

Nuclear spin imaging at the atomic level is essential for the understanding of fundamental biological phenomena and for applications such as drug discovery. The advent of novel nano-scale sensors has given hope of achieving the long-standing goal of single-protein, high spatial-resolution structure determination in their natural environment and ambient conditions. In particular, quantum sensors based on the spin-dependent photoluminescence of Nitrogen Vacancy (NV) centers in diamond have recently been used to detect nanoscale ensembles of external nuclear spins. While NV sensitivity is approaching single-spin levels, extracting relevant information from a very complex structure is a further challenge, since it requires not only the ability to sense the magnetic field of an isolated nuclear spin, but also to achieve atomic-scale spatial resolution. Here we propose a method that, by exploiting the coupling of the NV center to an intrinsic quantum memory associated with the Nitrogen nuclear spin, can reach a tenfold improvement in spatial resolution, down to atomic scales. The spatial resolution enhancement is achieved through coherent control of the sensor spin, which creates a dynamic frequency filter selecting only a few nuclear spins at a time. We propose and analyze a protocol that would allow not only sensing individual spins in a complex biomolecule, but also unraveling couplings among them, thus elucidating local characteristics of the molecule structure.

Ashok Ajoy; Ulf Bissbort; Mikhail D. Lukin; Ronald L. Walsworth; Paola Cappellaro

2014-07-11

83

Dynamically generated pure spin current in single-layer graphene  

NASA Astrophysics Data System (ADS)

The conductance mismatch problem limits the spin-injection efficiency significantly, and spin injection into graphene usually requires high-quality tunnel barriers to circumvent the conductance mismatch. We introduce an approach which enables the generation of pure spin current into single-layer graphene (SLG) that is free from electrical conductance mismatch by using dynamical spin injection. An experimental demonstration of spin-pumping-induced spin current generation and spin transport in SLG at room temperature was successfully achieved, and the spin coherence length was estimated to be 1.36 ?m by using a conventional theoretical model based on the Landau-Lifshitz-Gilbert equation. The spin coherence length is proportional to the quality of SLG, which indicates that spin relaxation in SLG is governed by the Elliot-Yafet mechanism, as was reported.

Tang, Zhenyao; Shikoh, Eiji; Ago, Hiroki; Kawahara, Kenji; Ando, Yuichiro; Shinjo, Teruya; Shiraishi, Masashi

2013-04-01

84

Detection of single electron spin resonance in a double quantum dota)  

NASA Astrophysics Data System (ADS)

Spin-dependent transport measurements through a double quantum dot are a valuable tool for detecting both the coherent evolution of the spin state of a single electron, as well as the hybridization of two-electron spin states. In this article, we discuss a model that describes the transport cycle in this regime, including the effects of an oscillating magnetic field (causing electron spin resonance) and the effective nuclear fields on the spin states in the two dots. We numerically calculate the current flow due to the induced spin flips via electron spin resonance, and we study the detector efficiency for a range of parameters. The experimental data are compared with the model and we find a reasonable agreement.

Koppens, F. H. L.; Buizert, C.; Vink, I. T.; Nowack, K. C.; Meunier, T.; Kouwenhoven, L. P.; Vandersypen, L. M. K.

2007-04-01

85

Single Spin Asymmetry in Charmonium Production  

NASA Astrophysics Data System (ADS)

We present estimates of single spin asymmetry (SSA) in the electroproduction of {J/?} taking into account the transverse momentum dependent (TMD) evolution of the gluon Sivers function and using Color Evaporation Model of charmonium production. We estimate SSA for JLab, HERMES, COMPASS and eRHIC energies using recent parameters for the quark Sivers functions which are fitted using an evolution kernel in which the perturbative part is resummed up to next-to-leading logarithms accuracy. We find that these SSAs are much smaller as compared to our first estimates obtained using DGLAP evolution but are comparable to our estimates obtained using TMD evolution where we had used approximate analytical solution of the TMD evolution equation for the purpose.

Godbole, Rohini M.; Kaushik, Abhiram; Misra, Anuradha; Rawoot, Vaibhav

2015-01-01

86

Ultrafast control of nuclear spins using only microwave pulses: towards switchable solid-state quantum gates  

E-print Network

We demonstrate the control of the alpha-proton nuclear spin, I=1/2, coupled to the stable radical CH(COOH)2, S=1/2, in a gamma-irradiated malonic acid single crystal using only microwave pulses. We show that, depending on the state of the electron spin mS=+/-1/2, the nuclear spin can be locked in a desired state or oscillate between mI=+1/2 and mI=-1/2 on the nanosecond time scale. This approach provides a fast and efficient way of controlling nuclear spin qubits and also enables the design of switchable spin-based quantum gates by addressing only the electron spin.

George Mitrikas; Yiannis Sanakis; Georgios Papavassiliou

2009-10-13

87

Ultrahigh spin thermopower and pure spin current in a single-molecule magnet  

PubMed Central

Using the non-equilibrium Green's function (NEGF) formalism within the sequential regime, we studied ultrahigh spin thermopower and pure spin current in single-molecule magnet(SMM), which is attached to nonmagnetic metal wires with spin bias and angle (?) between the easy axis of SMM and the spin orientation in the electrodes. A pure spin current can be generated by tuning the gate voltage and temperature difference with finite spin bias and the arbitrary angle except of . In the linear regime, large thermopower can be obtained by modifying Vg and the angles (?). These results are useful in fabricating and advantaging SMM devices based on spin caloritronics. PMID:24549224

Luo, Bo; Liu, Juan; Lü, Jing-Tao; Gao, Jin-Hua; Yao, Kai-Lun

2014-01-01

88

Nuclear Spin Cooling Using Overhauser-Field Selective Coherent Population Trapping  

NASA Astrophysics Data System (ADS)

We show that a quantum interference effect in optical absorption from two electronic spin states of a solid-state emitter can be used to prepare the surrounding environment of nuclear spins in well-defined states, thereby suppressing electronic spin dephasing. The coupled electron-nuclei system evolves into a coherent population trapping state by optical-excitation-induced nuclear-spin diffusion for a broad range of initial optical detunings. The spectroscopic signature of this evolution where the single-electron strongly modifies its environment is a drastic broadening of the dark resonance in optical absorption experiments. The large difference in electronic and nuclear time scales allows us to verify the preparation of nuclear spins in the desired state.

Issler, M.; Kessler, E. M.; Giedke, G.; Yelin, S.; Cirac, I.; Lukin, M. D.; Imamoglu, A.

2010-12-01

89

Electron spin echo and spin relaxation of low-symmetry Mn(2+)-complexes in ammonium oxalate monohydrate single crystal.  

PubMed

Pulse EPR experiments were performed on low concentration Mn(2+) ions in ammonium oxalate monohydrate single crystals at X-band, in the temperature range 4.2-60K at crystal orientation close to the D-tensor z-axis. Hyperfine lines of the resolved spin transitions were selectively excited by short nanosecond pulses. Electron spin echo signal was not observed for the low spin transition (+5/2?+3/2) suggesting a magnetic field threshold for the echo excitation. Echo appears for higher spin transitions with amplitude, which grows with magnetic field. Opposite behavior displays amplitude of echo decay modulations, which is maximal at low field and negligible for high field spin transitions. Electron spin-lattice relaxation was measured by the pulse saturation method. After the critical analysis of possible relaxation processes it was concluded that the relaxation is governed by Raman T(7)-process. The relaxation is the same for all spin transitions except the lowest temperatures (below 20K) where the high field transitions (-3/2?-1/2) and (-5/2?-3/2) have a slower relaxation rate. Electron spin echo dephasing is produced by electron spectral diffusion mainly, with a small contribution from instantaneous diffusion for all spin transitions. For the highest field transition (-5/2?-3/2) an additional contribution from nuclear spectral diffusion appears with resonance type enhancement at low temperatures. PMID:25064270

Hoffmann, Stanis?aw K; Lijewski, Stefan; Goslar, Janina; Mielniczek-Brzóska, Ewa

2014-09-01

90

Laser and Microwave Excitations of Rabi Oscillations of a Single Nitrogen-Vacancy Electron Spin in Diamond  

E-print Network

A collapse and revival shape of Rabi oscillations of a single Nitrogen-Vacancy (NV) center electron spin has been observed in diamond at room temperature. Because of hyperfine interaction between the host 14N nuclear spin and NV center electron spin, different orientation of the 14N nuclear spin leads to a triplet splitting of the transition between the ground ms=0 and excited states ms=1. Microwave can excite the three transitions equally to induce three independent nutations and the shape of Rabi oscillations is a combination of the three nutations. This result provides an innovative view of electron spin oscillations in diamond.

Chunyang Tang; Xin Hu; Xinyu Pan

2010-09-09

91

Coherent Control of a Single Electron Spin with Electric Fields  

Microsoft Academic Search

Manipulation of single spins is essential for spin-based quantum information\\u000aprocessing. Electrical control instead of magnetic control is particularly\\u000aappealing for this purpose, since electric fields are easy to generate locally\\u000aon-chip. We experimentally realize coherent control of a single electron spin\\u000ain a quantum dot using an oscillating electric field generated by a local gate.\\u000aThe electric field induces

K. C. Nowack; F. H. L. Koppens; Yu. V. Nazarov; L. M. K. Vandersypen

2007-01-01

92

Nuclear spin-state mixing in the NH2 radical  

Microsoft Academic Search

Nuclear spin-state mixing affects magnetic resonance and relaxation, thereby providing means to obtain information about molecular and electronic structure and, through spin polarization of nuclear targets, nucleon structure. In this report a calculation of matrix elements of the intramolecular nuclear spin-state mixing Hamiltonian is formulated and carried out for the proton (deuteron) and 14N (15N) nuclei in isotopes of the

A. R. Airne; A. S. Brill

2001-01-01

93

Solid state quantum memory using the 31P nuclear spin  

E-print Network

The transfer of information between different physical forms is a central theme in communication and computation, for example between processing entities and memory. Nowhere is this more crucial than in quantum computation, where great effort must be taken to protect the integrity of a fragile quantum bit. Nuclear spins are known to benefit from long coherence times compared to electron spins, but are slow to manipulate and suffer from weak thermal polarisation. A powerful model for quantum computation is thus one in which electron spins are used for processing and readout while nuclear spins are used for storage. Here we demonstrate the coherent transfer of a superposition state in an electron spin 'processing' qubit to a nuclear spin 'memory' qubit, using a combination of microwave and radiofrequency pulses applied to 31P donors in an isotopically pure 28Si crystal. The electron spin state can be stored in the nuclear spin on a timescale that is long compared with the electron decoherence time and then coherently transferred back to the electron spin, thus demonstrating the 31P nuclear spin as a solid-state quantum memory. The overall store/readout fidelity is about 90%, attributed to systematic imperfections in radiofrequency pulses which can be improved through the use of composite pulses. We apply dynamic decoupling to protect the nuclear spin quantum memory element from sources of decoherence. The coherence lifetime of the quantum memory element is found to exceed one second at 5.5K.

John J. L. Morton; Alexei M. Tyryshkin; Richard M. Brown; Shyam Shankar; Brendon W. Lovett; Arzhang Ardavan; Thomas Schenkel; Eugene E. Haller; Joel W. Ager; S. A. Lyon

2008-06-30

94

Macroscopic rotation of photon polarization induced by a single spin  

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

95

Macroscopic rotation of photon polarization induced by a single spin.  

PubMed

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

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

2015-01-01

96

Macroscopic rotation of photon polarization induced by a single spin  

PubMed Central

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

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

2015-01-01

97

Permeability of single nuclear pores.  

PubMed Central

In this first application of optical single transporter recording (OSTR), a recently established technique for optically monitoring the activity of single transporters in membrane patches (Tschödrich-Rotter and Peters. 1998. J. Microsc. 192:114-125), the passive permeability of the nuclear pore complex (NPC) was measured for a homologous series of hydrophilic probe molecules. Nuclei were isolated from Xenopus oocytes and firmly attached to filters containing small cylindrical pores. Transport through membrane patches spanning filter pores was measured by scanning microphotolysis. Thus the permeability coefficients of single NPCs were determined for fluorescently labeled dextrans of approximately 4, 10, and 20 kDa. Dextrans of >/=40 kDa could not permeate the NPC. The data were consistent with a model in which the NPC contains a single diffusion channel. By application of established theories for the restricted diffusion through small pores, the diffusion channel was approximated as a cylinder with a radius of 4.4-6.1 nm (mean 5. 35 nm). Because the transport rate constant of the single NPC was known, the equivalent length of the channel could be also determined and was found to be 40-50 nm (mean 44.5 nm). The symmetry of the NPC implies that a singular component such as the diffusion channel is located at the center of the NPC. Therefore a common transport pathway apparently mediates both passive and signal-dependent transport. To test this hypothesis, measurements of signal-dependent transport and of the mutual effects signal-dependent and passive transport may exert on each other are in progress. PMID:10388751

Keminer, O; Peters, R

1999-01-01

98

Electronic Spin Storage in an Electrically Readable Nuclear Spin Memory with a Lifetime >100 Seconds  

NASA Astrophysics Data System (ADS)

Electron spins are strong candidates with which to implement spintronics because they are both mobile and able to be manipulated. The relatively short lifetimes of electron spins, however, present a problem for the long-term storage of spin information. We demonstrated an ensemble nuclear spin memory in phosphorous-doped silicon, which can be read out electrically and has a lifetime exceeding 100 seconds. The electronic spin information can be mapped onto and stored in the nuclear spin of the phosphorus donors, and the nuclear spins can then be repetitively read out electrically for time periods that exceed the electron spin lifetime. We discuss how this memory can be used in conjunction with other silicon spintronic devices.

McCamey, D. R.; Van Tol, J.; Morley, G. W.; Boehme, C.

2010-12-01

99

Nuclear magnetometry studies of spin dynamics in quantum Hall systems  

NASA Astrophysics Data System (ADS)

We performed a nuclear magnetometry study on quantum Hall ferromagnet with a bilayer total filling factor of ?tot=2 . We found not only a rapid nuclear relaxation but also a sudden change in the nuclear-spin polarization distribution after a one-second interaction with a canted antiferromagnetic phase. We discuss the possibility of observing cooperative phenomena coming from nuclear-spin ensemble triggered by hyperfine interaction in quantum Hall system.

Fauzi, M. H.; Watanabe, S.; Hirayama, Y.

2014-12-01

100

Excited-State Spectroscopy and Control of Single Spins in Diamond  

NASA Astrophysics Data System (ADS)

Nitrogen Vacancy (NV) defect centers in diamond are a promising system for spin-based applications in quantum information and communication at room temperature. Using a combination of optical microscopy and spin resonance, the spin of individual NV centers can be initialized, manipulated and read out. These techniques have been used to study the long room temperature spin coherence times of NV centers as well as their interactions with nearby electrical and nuclear spins. There remain significant challenges, however, both in understanding the physics of these defects as well as the development of technologies based on their quantum properties. In particular, knowledge of the detailed structure of the orbital excited-state, which continues to be an active research area, is critical to ultra-fast quantum control schemes. Here we present recent experiments using single-spin resonant spectroscopy of the excited-state of an NV center at room temperature.ootnotetextG. D. Fuchs, V. V. Dobrovitski, R. Hanson, A. Batra, C. D. Weis, T. Schenkel, and D. D. Awschalom, Phys. Rev. Lett 101, 117601 (2008). We observe these spin levels over a broad range of magnetic fields allowing for a direct measurement of the zero-field splitting, g-factor and transverse anisotropy splitting. The latter of these is nearly zero in the ground-state spin levels, but plays an important role in the excited-state. In addition, we find strong hyperfine coupling between the nitrogen nuclear spin and the NV electronic spin in the excited-state. These findings will be discussed in the context of quantum control of single and coupled spins in diamond.

Fuchs, G. D.

2009-03-01

101

Dependence of nuclear spin singlet lifetimes on RF spin-locking power Stephen J. DeVience a,  

E-print Network

Dependence of nuclear spin singlet lifetimes on RF spin-locking power Stephen J. DeVience a: Received 6 January 2012 Revised 14 March 2012 Available online 28 March 2012 Keywords: Nuclear singlet of long-lived nuclear spin singlet states as a function of the strength of the RF spin-locking field

Rosen, Matthew S

102

Nanoscale magnetometry using a single spin system in diamond  

E-print Network

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.

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

2011-03-24

103

Single-parameter spin-pumping in driven metallic rings with spin-orbit coupling  

SciTech Connect

We consider the generation of a pure spin-current at zero bias voltage with a single time-dependent potential. To such end we study a device made of a mesoscopic ring connected to electrodes and clarify the interplay between a magnetic flux, spin-orbit coupling, and non-adiabatic driving in the production of a spin and electrical current. By using Floquet theory, we show that the generated spin to charge current ratio can be controlled by tuning the spin-orbit coupling.

Ramos, J. P.; Apel, V. M. [Departamento de Física, Universidad Católica del Norte, Angamos 0610, Casilla 1280, Antofagasta (Chile); Foa Torres, L. E. F. [Instituto de Física Enrique Gaviola (CONICET) and FaMAF, Universidad Nacional de Córdoba, Ciudad Universitaria 5000, Córdoba (Argentina); Orellana, P. A. [Departamento de Física, Universidad Técnica Federico Santa María, Avenida Vicuña Mackenna 3939, San Joaquin, Santiago (Chile)

2014-03-28

104

OSP Quantum Mechanics: Single Measurments of Spin States Worksheet  

NSDL National Science Digital Library

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.

Belloni, Mario

105

Orbital instabilities and spin-symmetry breaking in coupled-cluster calculations of indirect nuclear spin–spin coupling constants  

Microsoft Academic Search

The effect of orbital instabilities is investigated for spin-symmetry breaking perturbations, namely the Fermi-contact (FC) and spin–dipole (SD) contributions to the indirect nuclear spin–spin coupling constants. For the CO and N2 molecules the FC and SD contributions have been calculated and orbital-stability analyses for various interatomic distances have been carried out. This includes calculations at the Hartree–Fock self-consistent field (HF-SCF),

Alexander A. Auer; Jürgen Gauss

2009-01-01

106

Status of Sivers and Collins Single Spin Asymmetries  

E-print Network

The Sivers and Collins asymmetries are the most interesting Single Spin Asymmetries in semi-inclusive deeply inelastic scattering with transverse target polarization. In this talk we present our understanding of these phenomena.

A. V. Efremov; K. Goeke; P. Schweitzer

2007-02-15

107

Spin Modes in Nuclei and Nuclear Forces  

SciTech Connect

Spin modes in stable and unstable exotic nuclei are studied and important roles of tensor and three-body forces on nuclear structure are discussed. New shell model Hamiltonians, which have proper tensor components, are shown to explain shell evolutions toward drip-lines and spin properties of both stable and exotic nuclei, for example, Gamow-Teller transitions in {sup 12}C and {sup 14}C and an anomalous M1 transition in {sup 17}C. The importance and the necessity of the repulsive monopole corrections in isospin T = 1 channel to the microscopic two-body interactions are pointed out. The corrections are shown to lead to the proper shell evolutions in neutron-rich isotopes. The three-body force, in particular the Fujita-Miyazawa force induced by {Delta} excitations, is pointed out to be responsible for the repulsive corrections among the valence neutrons. The important roles of the three-body force on the energies and transitions in exotic oxygen and calcium isotopes are demonstrated.

Suzuki, Toshio [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan) and Center for Nuclear Study, University of Tokyo, Hirosawa, Wako-shi, Saitama, 351-0198 (Japan); Otsuka, Takaharu [Department of Physics and Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2011-05-06

108

Nuclear spin pair coherence in diamond for atomic scale magnetometry  

E-print Network

The nitrogen-vacancy (NV) centre, as a promising candidate solid state system of quantum information processing, its electron spin coherence is influenced by the magnetic field fluctuations due to the local environment. In pure diamonds, the environment consists of hundreds of C-13 nuclear spins randomly spreading in several nanometers range forming a spin bath. Controlling and prolonging the electron spin coherence under the influence of spin bath are challenging tasks for the quantum information processing. On the other hand, for a given bath distribution, many of its characters are encoded in the electron spin coherence. So it is natural to ask the question: is it possible to 'decode' the electron spin coherence, and extract the information about the bath structures? Here we show that, among hundreds of C-13 bath spins, there exist strong coupling clusters, which give rise to the millisecond oscillations of the electron spin coherence. By analyzing these oscillation features, the key properties of the cohe...

Zhao, Nan; Ho, Sai-Wah; Wen, Tsz-Kai; Liu, R B

2010-01-01

109

Uncovering many-body correlations in nanoscale nuclear spin baths by central spin decoherence  

E-print Network

Many-body correlations can yield key insights into the nature of interacting systems; however, detecting them is often very challenging in many-particle physics, especially in nanoscale systems. Here, taking a phosphorus donor electron spin in a natural-abundance 29Si nuclear spin bath as our model system, we discover both theoretically and experimentally that many-body correlations in nanoscale nuclear spin baths produce identifiable signatures in the decoherence of the central spin under multiple-pulse dynamical decoupling control. We find that when the number of decoupling -pulses is odd, central spin decoherence is primarily driven by second-order nuclear spin correlations (pairwise flip-flop processes). In contrast, when the number of -pulses is even, fourth-order nuclear spin correlations (diagonal interaction renormalized pairwise flip-flop processes) are principally responsible for the central spin decoherence. Many-body correlations of different orders can thus be selectively detected by central spin decoherence under different dynamical decoupling controls, providing a useful approach to probing many-body processes in nanoscale nuclear spin baths.

Wen-Long Ma; Gary Wolfowicz; Nan Zhao; Shu-Shen Li; John J. L. Morton; Ren-Bao Liu

2014-04-10

110

Collins Fragmentation and the Single Transverse Spin Asymmetry  

SciTech Connect

We study the Collins mechanism for the single transverse spin asymmetry in the collinear factorization approach. The correspondent twist-three fragmentation function is identified. We show that the Collins function calculated in this approach is universal.We further examine its contribution to the single transverse spin asymmetry of semi-inclusive hadron production in deep inelastic scattering and demonstrate that the transverse momentum dependent and twist-three collinear approaches are consistent in the intermediate transverse momentum region where both apply.

Yuan, Feng; Zhou, Jian

2009-03-26

111

Geodesic motion in the singly spinning black ring spacetime  

NASA Astrophysics Data System (ADS)

We present analytical solutions of the geodesic equations of test particles and light in the five-dimensional singly spinning black ring spacetime for special cases, since it does not appear possible to separate the Hamilton-Jacobi equation for singly spinning black rings in general. Based on the study of the polynomials in the equations of motion we characterize the motion of test particles and light and discuss the associated orbits.

Grunau, Saskia; Kagramanova, Valeria; Kunz, Jutta; Lämmerzahl, Claus

2012-11-01

112

All-optical initialization, readout, and coherent preparation of single silicon-vacancy spins in diamond.  

PubMed

The silicon-vacancy (SiV-) color center in diamond has attracted attention because of its unique optical properties. It exhibits spectral stability and indistinguishability that facilitate efficient generation of photons capable of demonstrating quantum interference. Here we show optical initialization and readout of electronic spin in a single SiV- center with a spin relaxation time of T1=2.4±0.2??ms. Coherent population trapping (CPT) is used to demonstrate coherent preparation of dark superposition states with a spin coherence time of T2?=35±3??ns. This is fundamentally limited by orbital relaxation, and an understanding of this process opens the way to extend coherence by engineering interactions with phonons. Hyperfine structure is observed in CPT measurements with the 29Si isotope which allows access to nuclear spin. These results establish the SiV- center as a solid-state spin-photon interface. PMID:25615330

Rogers, Lachlan J; Jahnke, Kay D; Metsch, Mathias H; Sipahigil, Alp; Binder, Jan M; Teraji, Tokuyuki; Sumiya, Hitoshi; Isoya, Junichi; Lukin, Mikhail D; Hemmer, Philip; Jelezko, Fedor

2014-12-31

113

Fluorescence thermometry enhanced by the quantum coherence of single spins in diamond  

PubMed Central

We demonstrate fluorescence thermometry techniques with sensitivities approaching 10 mK?Hz?1/2 based on the spin-dependent photoluminescence of nitrogen vacancy (NV) centers in diamond. These techniques use dynamical decoupling protocols to convert thermally induced shifts in the NV center's spin resonance frequencies into large changes in its fluorescence. By mitigating interactions with nearby nuclear spins and facilitating selective thermal measurements, these protocols enhance the spin coherence times accessible for thermometry by 45-fold, corresponding to a 7-fold improvement in the NV center’s temperature sensitivity. Moreover, we demonstrate these techniques can be applied over a broad temperature range and in both finite and near-zero magnetic field environments. This versatility suggests that the quantum coherence of single spins could be practically leveraged for sensitive thermometry in a wide variety of biological and microscale systems. PMID:23650364

Toyli, David M.; de las Casas, Charles F.; Christle, David J.; Dobrovitski, Viatcheslav V.; Awschalom, David D.

2013-01-01

114

Decoherence of proximate nuclear spin qubits in natural silicon  

E-print Network

Hybrid qubit systems combining electronic spins with surrounding proximate nuclear spins registers offer a promising avenue towards quantum information processing, with even multi-spin error correction protocols recently demonstrated in diamond. For the important platform offered by cryogenically cooled spins of donors in natural silicon such as phosphorus Si:P, however, the coherence behaviour of proximate nuclear spins are not well understood. We propose here that there may be an important contribution from a few (of order 100 spin pairs) symmetrically sited nuclear spin impurity pairs ("equivalent pairs"), which were not previously considered, as their effect is negligible outside the frozen core around an electron. If equivalent pairs represent a measurable source of decoherence, nuclear coherence decays could provide sensitive probes of the symmetries of electronic wavefunctions. We compare this model with the effect of a very large nuclear spin bath (10^8 weakly contributing pairs) outside the frozen core. We obtain T_{2n} values of order 1 second for both models, confirming the suitability of proximate nuclei in silicon as very long-lived spin qubits, in either case.

R. Guichard; S. J. Balian; G. Wolfowicz; P. A. Mortemousque; John J. L. Morton; T. S. Monteiro

2015-03-14

115

Room temperature hyperpolarization of nuclear spins in bulk  

PubMed Central

Dynamic nuclear polarization (DNP), a means of transferring spin polarization from electrons to nuclei, can enhance the nuclear spin polarization (hence the NMR sensitivity) in bulk materials at most 660 times for 1H spins, using electron spins in thermal equilibrium as polarizing agents. By using electron spins in photo-excited triplet states instead, DNP can overcome the above limit. We demonstrate a 1H spin polarization of 34%, which gives an enhancement factor of 250,000 in 0.40 T, while maintaining a bulk sample (?0.6 mg, ?0.7 × 0.7 × 1 mm3) containing >1019 1H spins at room temperature. Room temperature hyperpolarization achieved with DNP using photo-excited triplet electrons has potentials to be applied to a wide range of fields, including NMR spectroscopy and MRI as well as fundamental physics. PMID:24821773

Tateishi, Kenichiro; Negoro, Makoto; Nishida, Shinsuke; Kagawa, Akinori; Morita, Yasushi; Kitagawa, Masahiro

2014-01-01

116

Spin-orbit coupling and spin relaxation rate in singly charged pi-conjugated polymer chains  

NASA Astrophysics Data System (ADS)

In inorganic semiconductor spintronics the spin-diffusion length is usually limited by spin-orbit coupling. Here we examine the effect of spin-orbit coupling in organic spintronics. We consider singly charged pi-conjugated polymer chains. We show that the diagonal matrix elements for spin-orbit coupling are zero. Even the off-diagonal matrix elements are zero or negligibly small unless a twisted, non-planar polymer chain is considered. We calculate these matrix elements as a function of twist-angle using tight-binding wavefunctions. We show that time reversal symmetry prevents spin-orbit induced spin-precession and propose a phonon-assisted spin-flip process.

Rybicki, James; Nguyen, Tho Duc; Sheng, Yugang; Wohlgenannt, Markus

2010-03-01

117

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

PubMed Central

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

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

118

Nuclear spin-induced Cotton-Mouton effect in molecules  

NASA Astrophysics Data System (ADS)

In nuclear magneto-optic spectroscopy, effects of nuclear magnetization are detected in light passing through a sample containing spin-polarized nuclei. An optical analogue of nuclear magnetic resonance (NMR) chemical shift has been predicted and observed in the nuclear spin optical rotation of linearly polarized light propagating parallel to the nuclear magnetization. A recently proposed magneto-optic analogue of the NMR spin-spin coupling, the nuclear spin-induced Cotton-Mouton (NSCM) effect entails an ellipticity induced to linearly polarized light when passing through a medium with the nuclear spins polarized in a direction perpendicular to the light beam. Here we present a first-principles electronic structure formulation of NSCM in terms of response theory as well as ab initio and density-functional theory calculations for small molecules. The roles of basis set (we use completeness-optimized sets), electron correlation, and relativistic effects are discussed. It is found that the explicitly temperature-dependent contribution to NSCM, arising from the partial orientation of the molecules due to the nuclear magnetization, typically dominates the effect. This part of NSCM is proportional to the tensor product of molecular polarizability and the NMR direct dipolar coupling tensor. Hence, NSCM provides a means of investigating the dipolar coupling and, thus, molecular structure in a formally isotropic medium. Overall ellipticities of the order of magnitude of 10-8…10-7 rad/(M cm) are predicted for fully polarized nuclei. These should be detectable with modern instrumentation in the Voigt setup.

Fu, Li-juan; Vaara, Juha

2013-05-01

119

Coherent detection of mechanical motion with a single spin qubit  

NASA Astrophysics Data System (ADS)

Mechanical systems can be influenced by a wide variety of extremely small forces, ranging from gravitational to optical, electrical, and magnetic. When mechanical resonators are scaled down to nanometer-scale dimensions, these forces can be harnessed to enable coupling to individual quantum systems. We present results showing that the coherent evolution of a single electronic spin associated with a Nitrogen Vacancy (NV) center in diamond can be coupled to the motion of a magnetized mechanical resonator. Specifically we use coherent manipulation of the spin to sense the driven and Brownian motion of the resonator under ambient conditions at a precision of 5 picometers. We discuss potential future applications of this technique including the detection of the zero-point fluctuations of a mechanical resonator, the realization of strong spin-phonon coupling at a single quantum level, and the implementation of quantum spin transducers.

Kolkowitz, Shimon; Unterreithmeier, Quirin; Jayich, Ania; Bennett, Steven; Rabl, Peter; Harris, Jack; Lukin, Mikhail

2012-06-01

120

Engineering Nuclear spin has now been associated with Nobel Prizes  

E-print Network

Chemical Engineering Nuclear spin has now been associated with Nobel Prizes in Physics, Chemistry-2003, Professor Reimer won the Donald Sterling Noyce Prize, the AIChE Northern California Section Award and the UC

121

Interaction induced deformation in momentum distribution of spin polarized nuclear matter  

E-print Network

Effects of spin polarization on the structure of symmetric nuclear matter and pure neutron matter are investigated. We show that the spin polarization induces a deformation of the Fermi spheres for nucleons with spin parallel and opposite to the polarization axes. This feature can be related to the structure of the one pion exchange contribution to a realistic nucleon-nucleon interaction. While the anisotropies in the momentum distribution lower the energy of the system by small amount, the associated variations of the single particle energies with the angle between the polarization axis and the particle momentum are significant.

T. Frick; H. Müther; A. Sedrakian

2002-03-19

122

Optical hyperpolarization of 13C nuclear spins in nanodiamond ensembles  

E-print Network

Here we propose and analyse in detail protocols that can achieve rapid hyperpolarization of 13C nuclear spins in randomly oriented ensembles of nanodiamonds at room temperature. Our protocols exploit a combination of optical polarization of electron spins in nitrogen-vacancy centers and the transfer of this polarization to 13C nuclei by means of microwave control to overcome the severe challenges that are posed by the random orientation of the nanodiamonds and their nitrogen-vacancy centers. Specifically, these random orientations result in exceedingly large energy variations of the electron spin levels that render the polarization and coherent control of the nitrogen-vacancy center electron spins as well as the control of their coherent interaction with the surrounding 13C nuclear spins highly inefficient. We address these challenges by a combination of an off-resonant microwave double resonance scheme in conjunction with a realization of the integrated solid effect which, together with adiabatic rotations of external magnetic fields or rotations of nanodiamonds, leads to a protocol that achieves high levels of hyperpolarization of the entire nuclear-spin bath in a randomly oriented ensemble of nanodiamonds even at room temperature. This hyperpolarization together with the long nuclear spin polarization lifetimes in nanodiamonds and the relatively high density of 13C nuclei has the potential to result in a major signal enhancement in 13C nuclear magnetic resonance imaging and suggests functionalized and hyperpolarized nanodiamonds as a unique probe for molecular imaging both in vitro and in vivo.

Q. Chen; I. Schwarz; F. Jelezko; A. Retzker; M. B. Plenio

2015-04-09

123

Nuclear Spins in a Nanoscale Device for Quantum Information Processing  

E-print Network

Coherent oscillations between any two levels from four nuclear spin states of I=3/2 have been demonstrated in a nanometre-scale NMR semiconductor device, where nuclear spins are all-electrically controlled. Using this device, we discuss quantum logic operations on two fictitious qubits of the I=3/2 system, and propose a quantum state tomography scheme based on the measurement of longitudinal magnetization, $M_z$.

S. K. Ozdemir; A. Miranowicz; T. Ota; G. Yusa; N. Imoto; Y. Hirayama

2006-12-29

124

Strong mechanical driving of a single electron spin  

E-print Network

Quantum devices for sensing and computing applications require coherent quantum systems which can be manipulated in a fast and robust way. Such quantum control is typically achieved using external electric or magnetic fields which drive the system's orbital or spin degrees of freedom. However, most of these approaches require complex and unwieldy antenna or gate structures, and with few exceptions are limited to the regime of weak driving. Here, we present a novel approach to strongly and coherently drive a single electron spin in the solid state using internal strain fields in an integrated quantum device. Specifically, we study individual Nitrogen-Vacancy (NV) spins embedded in diamond mechanical oscillators and exploit the intrinsic strain coupling between spin and oscillator to strongly drive the spins. As hallmarks of the strong driving regime, we directly observe the energy spectrum of the emerging phonon-dressed states and employ our strong, continuous driving for enhancement of the NV spin coherence time. Our results constitute a first step towards strain-driven, integrated quantum devices and open new perspectives to investigate unexplored regimes of strongly driven multi-level systems and to study exotic spin dynamics in hybrid spin-oscillator devices.

Arne Barfuss; Jean Teissier; Elke Neu; Andreas Nunnenkamp; Patrick Maletinsky

2015-03-23

125

Nanomagnetism: Spin doctors play with single electrons  

NASA Astrophysics Data System (ADS)

It is now possible to prepare a semiconductor quantum dot that contains a single magnetic atom, and then add just one extra electron or 'hole' to it, opening up the possibility of a new era in spintronics.

Erwin, Steven C.

2006-11-01

126

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

E-print Network

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.

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

127

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

NASA Astrophysics Data System (ADS)

Building upon the demonstration of coherent control and single-shot readout of the electron and nuclear spins of individual 31P 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 31P nucleus of a single P donor in isotopically purified 28Si. 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.

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

2015-04-01

128

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

PubMed

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. PMID:25783435

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

2015-04-22

129

Nuclear-spin observation of noise spectra in semiconductors  

SciTech Connect

We propose a systematic method of obtaining the spectra of noises that cause the decoherence of spins in solids. Based on this method, we experimentally show that this method can be applied to nuclear spins in semiconductors. We clarify that the spectral intensity must be derived from the long-time tail of the multiple-echo decay. To obtain higher-frequency noise, the inversion-pulse interval must be as short as possible, which required us to employ the alternating-phase Carr-Purcell sequence instead of the widely used Carr-Purcell Meiboom-Gill. For {sup 75}As nuclear spin in variously-doped GaAs, we observed a Lorentzian spectrum, instead of the commonly observed 1/f spectrum. This indicates that the nuclear spins are indeed in a coherently-controlled state.

Sasaki, Susumu; Nishimori, Masashi; Kawanago, Takashi [Department of Materials Science, Niigata University, Niigata 950-2181 (Japan); Yuge, Tatsuro [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Hirayama, Yoshiro [Department of Physics, Tohoku University, Sendai 980-8578, Japan and JST-ERATO Nuclear Spin Electronics Project, Sendai 980-8578 (Japan)

2013-12-04

130

Pulsed Nuclear Magnetic Resonance: Spin Echoes MIT Department of Physics  

E-print Network

Pulsed Nuclear Magnetic Resonance: Spin Echoes MIT Department of Physics (Dated: February 5, 2014) In this experiment, the phenomenon of Nuclear Magnetic Resonance (NMR) is used to determine the magnetic moments that a particle with angular momentum I and magnetic moment µ = I placed in a uniform mag- netic field B0

Seager, Sara

131

High spin nuclear structure studies using the spin spectrometer  

Microsoft Academic Search

The gamma-gamma correlation technique is used to generate two-dimensional histograms of gamma ray energy from gamma-gamma coincidence data. The spin spectrometer at Oak Ridge National Laboratory is used to study the continuum gamma-rays from the reaction ¹°°Mo + ³⁴S at 144 MeV beam energy. Double and triple correlation spectra for transitions in rotational bands are obtained which exhibit characteristic valleys.

1986-01-01

132

Calculation of nuclear spin-spin coupling constants using frozen density embedding  

SciTech Connect

We present a method for a subsystem-based calculation of indirect nuclear spin-spin coupling tensors within the framework of current-spin-density-functional theory. Our approach is based on the frozen-density embedding scheme within density-functional theory and extends a previously reported subsystem-based approach for the calculation of nuclear magnetic resonance shielding tensors to magnetic fields which couple not only to orbital but also spin degrees of freedom. This leads to a formulation in which the electron density, the induced paramagnetic current, and the induced spin-magnetization density are calculated separately for the individual subsystems. This is particularly useful for the inclusion of environmental effects in the calculation of nuclear spin-spin coupling constants. Neglecting the induced paramagnetic current and spin-magnetization density in the environment due to the magnetic moments of the coupled nuclei leads to a very efficient method in which the computationally expensive response calculation has to be performed only for the subsystem of interest. We show that this approach leads to very good results for the calculation of solvent-induced shifts of nuclear spin-spin coupling constants in hydrogen-bonded systems. Also for systems with stronger interactions, frozen-density embedding performs remarkably well, given the approximate nature of currently available functionals for the non-additive kinetic energy. As an example we show results for methylmercury halides which exhibit an exceptionally large shift of the one-bond coupling constants between {sup 199}Hg and {sup 13}C upon coordination of dimethylsulfoxide solvent molecules.

Götz, Andreas W., E-mail: agoetz@sdsc.edu [San Diego Supercomputer Center, University of California San Diego, 9500 Gilman Dr MC 0505, La Jolla, California 92093-0505 (United States); Autschbach, Jochen [Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000 (United States)] [Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000 (United States); Visscher, Lucas, E-mail: visscher@chem.vu.nl [Amsterdam Center for Multiscale Modeling (ACMM), VU University Amsterdam, Theoretical Chemistry, De Boelelaan 1083, 1081 HV Amsterdam (Netherlands)] [Amsterdam Center for Multiscale Modeling (ACMM), VU University Amsterdam, Theoretical Chemistry, De Boelelaan 1083, 1081 HV Amsterdam (Netherlands)

2014-03-14

133

Using nanoscale transistors to measure single donor spins in semiconductors  

SciTech Connect

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

Sarovar, M.; Young, K. C.; Whaley, K. B.; Schenkel, Thomas

2008-12-01

134

High spin nuclear structure studies using the spin spectrometer  

SciTech Connect

The gamma-gamma correlation technique is used to generate two-dimensional histograms of gamma ray energy from gamma-gamma coincidence data. The spin spectrometer at Oak Ridge National Laboratory is used to study the continuum gamma-rays from the reaction /sup 100/Mo + /sup 34/S at 144 MeV beam energy. Double and triple correlation spectra for transitions in rotational bands are obtained which exhibit characteristic valleys. These valleys are shown to depend on the moment of inertia of the rotational bands and the gamma ray spreading width. 5 refs., 4 figs., 4 tabs. (DWL)

Lee, I.Y.

1986-01-01

135

Entangled Absorption of a Single Photon with a Single Spin in Diamond  

NASA Astrophysics Data System (ADS)

Quantum entanglement, a key resource for quantum information science, is inherent in a solid. It has been recently shown that entanglement between a single optical photon and a single spin qubit in a solid is generated via spontaneous emission. However, entanglement generation by measurement is rather essential for quantum operations. We here show that the physics behind the entangled emission can be time reversed to demonstrate entangled absorption mediated by an inherent spin-orbit entanglement in a single nitrogen vacancy center in diamond. Optical arbitrary spin state preparation and complete spin state tomography reveal the fidelity of the entangled absorption to be 95%. With the entangled emission and absorption of a photon, materials can be spontaneously entangled or swap their quantum state based on the quantum teleportation scheme.

Kosaka, Hideo; Niikura, Naeko

2015-02-01

136

Control of single-spin magnetic anisotropy by exchange coupling.  

PubMed

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

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

2014-01-01

137

Computational quantum chemistry for single Heisenberg spin couplings made simple: Just one spin flip required  

NASA Astrophysics Data System (ADS)

We highlight a simple strategy for computing the magnetic coupling constants, J, for a complex containing two multiradical centers. On the assumption that the system follows Heisenberg Hamiltonian physics, J is obtained from a spin-flip electronic structure calculation where only a single electron is excited (and spin-flipped), from the single reference with maximum hat{S}_z, M, to the M - 1 manifold, regardless of the number of unpaired electrons, 2M, on the radical centers. In an active space picture involving 2M orbitals, only one ? electron is required, together with only one ? hole. While this observation is extremely simple, the reduction in the number of essential configurations from exponential in M to only linear provides dramatic computational benefits. This (M, M - 1) strategy for evaluating J is an unambiguous, spin-pure, wave function theory counterpart of the various projected broken symmetry density functional theory schemes, and likewise gives explicit energies for each possible spin-state that enable evaluation of properties. The approach is illustrated on five complexes with varying numbers of unpaired electrons, for which one spin-flip calculations are used to compute J. Some implications for further development of spin-flip methods are discussed.

Mayhall, Nicholas J.; Head-Gordon, Martin

2014-10-01

138

Computational quantum chemistry for single Heisenberg spin couplings made simple: just one spin flip required.  

PubMed

We highlight a simple strategy for computing the magnetic coupling constants, J, for a complex containing two multiradical centers. On the assumption that the system follows Heisenberg Hamiltonian physics, J is obtained from a spin-flip electronic structure calculation where only a single electron is excited (and spin-flipped), from the single reference with maximum S?z, M, to the M - 1 manifold, regardless of the number of unpaired electrons, 2M, on the radical centers. In an active space picture involving 2M orbitals, only one ? electron is required, together with only one ? hole. While this observation is extremely simple, the reduction in the number of essential configurations from exponential in M to only linear provides dramatic computational benefits. This (M, M - 1) strategy for evaluating J is an unambiguous, spin-pure, wave function theory counterpart of the various projected broken symmetry density functional theory schemes, and likewise gives explicit energies for each possible spin-state that enable evaluation of properties. The approach is illustrated on five complexes with varying numbers of unpaired electrons, for which one spin-flip calculations are used to compute J. Some implications for further development of spin-flip methods are discussed. PMID:25296788

Mayhall, Nicholas J; Head-Gordon, Martin

2014-10-01

139

High precision quantum control of single donor spins in silicon  

E-print Network

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.

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

2007-05-15

140

Switching of a Single Atomic Spin Induced by Spin Injection:. a Model Calculation  

NASA Astrophysics Data System (ADS)

Toward the manipulation of a single atomic spin, we theoretically study the switching of a localized quantum spin S = (Sx, Sy, Sz) induced by spin injection in electrode/S/electrode junctions. This S has a uniaxial anisotropy energy, - |D|Sz2, which shows the bistable potential between Sz = -S and S, with D being an anisotropy constant. Furthermore, S interacts with the atomic vibration. For the initial state of Sz = -S, we consider a situation in which up-spin electrons exhibit the spin-flip tunneling from the left electrode to the right one through an exchange interaction between the electron spin and S. Using the master equation approach, we investigate the time t dependence of the current I, the expectation value of Sz, , and that of the vibration quantum number, , of an S = 2 system, which corresponds to an Fe atom on CuN surface. The systems exhibit the switching or nonswitching depending on the transition probability due to spin-atomic vibration interaction within a period of 10 ns. In addition, the t dependence of I and is explained on the basis of and the probability distribution.

Kokado, S.; Harigaya, K.; Sakuma, A.

2009-06-01

141

Electrical Detection of Spin Pumping due to the Precessing Magnetization of a Single Ferromagnet  

E-print Network

Electrical Detection of Spin Pumping due to the Precessing Magnetization of a Single Ferromagnet M of spin pumping, using a lateral normal-metal/ferromagnet/normal- metal device, where a single ferromagnet in ferromagnetic resonance pumps spin-polarized electrons into the normal metal, resulting in spin accumulation

van der Wal, Caspar H.

142

Universal dynamical decoupling of a single solid-state spin from a spin bath  

E-print Network

Controlling the interaction of a single quantum system with its environment is a fundamental challenge in quantum science and technology. We dramatically suppress the coupling of a single spin in diamond with the surrounding spin bath by using double-axis dynamical decoupling. The coherence is preserved for arbitrary quantum states, as verified by quantum process tomography. The resulting coherence time enhancement is found to follow a general scaling with the number of decoupling pulses. No limit is observed for the decoupling action up to 136 pulses, for which the coherence time is enhanced more than 25 times compared to spin echo. These results uncover a new regime for experimental quantum science and allow to overcome a major hurdle for implementing quantum information protocols.

de Lange, G; Ristè, D; Dobrovitski, V V; Hanson, R

2010-01-01

143

Universal dynamical decoupling of a single solid-state spin from a spin bath  

E-print Network

Controlling the interaction of a single quantum system with its environment is a fundamental challenge in quantum science and technology. We dramatically suppress the coupling of a single spin in diamond with the surrounding spin bath by using double-axis dynamical decoupling. The coherence is preserved for arbitrary quantum states, as verified by quantum process tomography. The resulting coherence time enhancement is found to follow a general scaling with the number of decoupling pulses. No limit is observed for the decoupling action up to 136 pulses, for which the coherence time is enhanced more than 25 times compared to spin echo. These results uncover a new regime for experimental quantum science and allow to overcome a major hurdle for implementing quantum information protocols.

G. de Lange; Z. H. Wang; D. Ristè; V. V. Dobrovitski; R. Hanson

2010-10-21

144

Quantum and classical correlations in electron-nuclear spin echo  

SciTech Connect

The quantum properties of dynamic correlations in a system of an electron spin surrounded by nuclear spins under the conditions of free induction decay and electron spin echo have been studied. Analytical results for the time evolution of mutual information, classical part of correlations, and quantum part characterized by quantum discord have been obtained within the central-spin model in the high-temperature approximation. The same formulas describe discord in both free induction decay and spin echo although the time and magnetic field dependences are different because of difference in the parameters entering into the formulas. Changes in discord in the presence of the nuclear polarization ?{sub I} in addition to the electron polarization ?{sub S} have been calculated. It has been shown that the method of reduction of the density matrix to a two-spin electron-nuclear system provides a qualitatively correct description of pair correlations playing the main role at ?{sub S} ? ?{sub I} and small times. At large times, such correlations decay and multispin correlations ensuring nonzero mutual information and zero quantum discord become dominant.

Zobov, V. E., E-mail: rsa@iph.krasn.ru [Russian Academy of Sciences, Kirensky Institute of Physics, Siberian Branch (Russian Federation)

2014-11-15

145

Strong driving of a single spin using arbitrarily polarized fields  

NASA Astrophysics Data System (ADS)

The strong-driving regime occurs when a quantum two-level system is driven with an external field whose amplitude is greater than or equal to the energy splitting between the system's states and is typically identified with the breaking of the rotating wave approximation (RWA). We report an experimental study in which the spin of a single nitrogen-vacancy (NV) center in diamond is strongly driven with microwave fields of arbitrary polarization. We measure the NV center spin dynamics beyond the RWA and characterize the limitations of this technique for generating high-fidelity quantum gates. Using circularly polarized microwave fields, the NV spin can be harmonically driven in its rotating frame regardless of the field amplitude, thus allowing rotations around arbitrary axes. Our approach can effectively remove the RWA limit in quantum-sensing schemes and assist in increasing the number of operations in QIP protocols.

London, P.; Balasubramanian, P.; Naydenov, B.; McGuinness, L. P.; Jelezko, F.

2014-07-01

146

A Magnetic Switch for Spin-Catalyzed Interconversion of Nuclear Spin Yongjun Li,  

E-print Network

A Magnetic Switch for Spin-Catalyzed Interconversion of Nuclear Spin Isomers Yongjun Li, Xuegong guest@host complexes2­4 oH2@C60 and pH2@C60, respectively. We have developed5 the following procedure catalysts for the back conversion of *pH2@C60 to eH2@C60.5 We reasoned that if a derivative of H2@C60 could

Turro, Nicholas J.

147

Spin dynamics of a confined electron interacting with magnetic or nuclear spins: A semiclassical approach  

NASA Astrophysics Data System (ADS)

A physically transparent and mathematically simple semiclassical model is employed to examine dynamics in the central-spin problem. The results reproduce previous findings obtained by various quantum approaches and, at the same time, provide information on the electron spin dynamics and Berry's phase effects over a wider range of experimentally relevant parameters than available previously. This development is relevant to dynamics of bound magnetic polarons and spin dephasing of an electron trapped by an impurity or a quantum dot, and coupled by a contact interaction to neighboring localized magnetic impurities or nuclear spins. Furthermore, it substantiates the applicability of semiclassical models to simulate dynamic properties of spintronic nanostructures with a mesoscopic number of spins.

Dietl, Tomasz

2015-03-01

148

Dynamic nuclear polarization from current-induced electron spin polarization  

NASA Astrophysics Data System (ADS)

Current-induced electron spin polarization is shown to produce nuclear hyperpolarization through dynamic nuclear polarization. Saturated fields of several millitesla are generated upon the application of an electric field over a time scale of 100 s in InGaAs epilayers and measured using optical Larmor magnetometry. We show that, in contrast to previous demonstrations of current-induced dynamic nuclear polarization, the direction of the current relative to the crystal axis and external magnetic field may be used to control the magnitude and direction of the saturation nuclear field.

Trowbridge, C. J.; Norman, B. M.; Kato, Y. K.; Awschalom, D. D.; Sih, V.

2014-08-01

149

Quantum Information Transport in Nuclear Spin Chains  

Microsoft Academic Search

In many solid-state proposals for quantum computers, the transport of information over relatively short distances inside the quantum processor itself is an essential task, and one for which relying on photons, and therefore on a frequent exchanging of information between solid-state and light qubits, could be too costly. Quantum wires based on spins could be a viable alternative leading to

Paola Cappellaro; David Cory

2007-01-01

150

Cryogenic single-chip electron spin resonance detector.  

PubMed

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/Hz(1/2) at 100 kHz offset from the 20 GHz carrier. At 4 K, the frequency noise is about 1 Hz/Hz(1/2) at 10 kHz offset. The spin sensitivity measured with a sample of DPPH is 10(8)spins/Hz(1/2) at 300 K and down to 10(6)spins/Hz(1/2) at 4 K. PMID:25261743

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

2014-10-01

151

Spin-gating of a conventional aluminum single electron transistor  

NASA Astrophysics Data System (ADS)

We report the realization of a single electron transistor in which electron transport from an aluminum source electrode to an aluminum drain electrode via an aluminum island is controlled by spins in a capacitively coupled magnetic gate electrode. The origin of the effect is in the change of the chemical potential on the gate, formed by the ferromagnetic semiconductor GaMnAs, with changing the direction of the magnetization. In agreement with experimental observations, microscopically calculated anisotropies of the chemical potential with respect to the magnetization orientation are of the order of 10?V which is comparable to the electrical gate voltages required to control the on and off state of the single electron transistor. Our phenomenon belongs to the family of anisotropic magnetoresistance effects which can be observed in ohmic, tunneling or other device geometries. In our case, the entire phenomenon is coded in the dependence of the chemical potential on the spin orientation which allowed us to remove the spin functionality from all current contacts and channels and place it in the capacitively coupled gate electrode. Our spintronic device therefore operates without spin current.

Zarbo, Liviu P.; Ciccarelli, Chiara; Irvine, Andy; Wunderlich, Jörg; Champion, Richard; Gallagher, Brian; Jungwirth, Tomáš; Ferguson, Andrew

2012-02-01

152

Observing a Quantum Phase Transition by Measuring a Single Spin  

E-print Network

We show that the ground-state quantum correlations of an Ising model can be detected by monitoring the time evolution of a single spin alone, and that the critical point of a quantum phase transition is detected through a maximum of a suitably defined observable. A proposed implementation with trapped ions realizes an experimental probe of quantum phase transitions which is based on quantum correlations and scalable for large system sizes.

Manuel Gessner; Michael Ramm; Hartmut Haeffner; Andreas Buchleitner; Heinz-Peter Breuer

2014-08-11

153

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

E-print Network

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 ...

Yang, Jamie Chiaming

2008-01-01

154

Homonuclear single transition correlation spectroscopy of rare spins  

NASA Astrophysics Data System (ADS)

An alternative approach for rare spin homonuclear correlation spectroscopy is proposed and examined, which does not involve double quantum evolution. It relies instead on double quantum filtration resulting in a set of single transitions. This is followed by evolution and zero quantum mixing, generating a diagonal suppressed, single transition correlation spectrum that attains an efficiency matching the bound on unitary coherence transfer, but in fact benefits from reduced relaxation losses. This generally results in modest signal intensity improvement in a given measurement time, compared to the most efficient INADEQUATE variant. Results on 13C are reported and confirm the expected behavior.

Ramesh, V.; George, C.; Chandrakumar, N.

2009-06-01

155

Ultrafast Nuclear Spin Polarization by Short Laser Pulses  

SciTech Connect

We propose a novel scheme to realize ultrafast nuclear spin polarization by short laser pulses. Combined use of the hyperfine interaction and the static electric field is the key for that. The idea is specifically applied to various isotopes of alkaline-earth atoms, Mg and Ca, with nuclear spin I = 1/2, 3/2, 5/2, and 7/2. After the detailed theoretical analysis, we find that spin-polarization as high as 88%, 66%, 33%, and 25%, respectively, for I = 1/2, 3/2, 5/2, and 7/2, can be attained in the time scale of a few to tens of ns, which is at least 2-3 orders of magnitude shorter than any known optical methods. Due to this ultrafast nature, our scheme is applicable not only for stable nuclei but also unstable nuclei with a lifetime as short as a few {mu}s.

Nakajima, Takashi [Institute of Advanced Energy, Kyoto University Gokasho, Uji, Kyoto 611-0011 (Japan)

2008-02-06

156

Longitudinal spin-dependent correlations in nuclear matter  

NASA Astrophysics Data System (ADS)

A Jastrow-type wave function, with the two-body correlation factor depending on the spin-isospin state of the particles, is used for variational calculations of the energy per particle of infinite Fermi systems. Results are presented for nuclear matter and neutron matter using two semi-realistic potentials.

Fabrocini, A.; Fantoni, S.

1981-04-01

157

Enrichment of nuclear spin isomers of molecules by bichromatic field  

NASA Astrophysics Data System (ADS)

A theoretical model for the enrichment of nuclear spin isomers of molecules by two electromagnetic fields is developed. The fields are resonant with the rotational transitions in the ground electronic and vibrational state of the molecule. Numerical calculations reveal a complicated dependence of the isomer enrichment on the radiation frequencies that consists of three peaks with different shapes, widths and amplitudes.

Chapovsky, P. L.; Wilson-Gordon, A. D.

2015-03-01

158

A silicon-based nuclear spin quantum computer  

Microsoft Academic Search

Quantum computers promise to exceed the computational efficiency of ordinary classical machines because quantum algorithms allow the execution of certain tasks in fewer steps. But practical implementation of these machines poses a formidable challenge. Here I present a scheme for implementing a quantum-mechanical computer. Information is encoded onto the nuclear spins of donor atoms in doped silicon electronic devices. Logical

B. E. Kane

1998-01-01

159

Spins as qubits: Quantum information processing by nuclear magnetic resonance  

E-print Network

of the amount of energy dissipated per logical operation in successive generations of computer hardware. SomeSpins as qubits: Quantum information processing by nuclear magnetic resonance Dieter Suter1,a and T 2007; published online 5 February 2008 Storing information in quantum mechanical degrees of freedom

Suter, Dieter

160

Nuclear Spin Gyroscope Based on an Atomic Comagnetometer  

SciTech Connect

We describe a nuclear spin gyroscope based on an alkali-metal-noble-gas comagnetometer. Optically pumped alkali-metal vapor is used to polarize the noble-gas atoms and detect their gyroscopic precession. Spin precession due to magnetic fields as well as their gradients and transients can be cancelled in this arrangement. The sensitivity is enhanced by using a high-density alkali-metal vapor in a spin-exchange relaxation free regime. With a K-{sup 3}He comagnetometer we demonstrate rotation sensitivity of 5x10{sup -7} rad s{sup -1} Hz{sup -1/2}, equivalent to a magnetic field sensitivity of 2.5 fT/Hz{sup 1/2}. The rotation signal can be increased by a factor of 10 using {sup 21}Ne with a smaller magnetic moment. The comagnetometer is also a promising tool in searches for anomalous spin couplings beyond the standard model.

Kornack, T.W.; Ghosh, R.K.; Romalis, M.V. [Department of Physics, Princeton University, Princeton, New Jersey 08550 (United States)

2005-12-02

161

Engineering nuclear spin dynamics with optically pumped nitrogen-vacancy center  

E-print Network

We present a general theory for using an optically pumped diamond nitrogen-vacancy center as a tunable, non-equilibrium bath to control a variety of nuclear spin dynamics (such as dephasing, relaxation, squeezing, polarization, etc.) and the nuclear spin noise. It opens a new avenue towards engineering the dissipative and collective nuclear spin evolution and solves an open problem brought up by the $^{13}$C nuclear spin noise suppression experiment [E. Togan \\textit{et al}., Nature 478, 497 (2011)].

Ping Wang; Jiangfeng Du; Wen Yang

2015-03-01

162

Quantum read-out and fast initialization of nuclear spin qubits with electric currents  

E-print Network

Nuclear spin qubits have the longest coherence times in the solid state, but their quantum read-out and initialization is a great challenge. We present a theory for the interaction of an electric current with the nuclear spins of donor impurities in semiconductors. The theory yields a sensitivity criterion for quantum detection of nuclear spin states using electrically detected magnetic resonance, as well as an all electrical method for fast nuclear spin qubit initialization.

Noah Stemeroff; Rogerio de Sousa

2011-10-01

163

Nuclear moments of inertia at high spin  

SciTech Connect

The competition between collective motion and alignment at high spin can be evaluated by measuring two complementary dynamic moments of inertia. The first, I band, measured in ..gamma..-..gamma.. correlation experiments, relates to the collective properties of the nucleus. A new moment of inertia I/sub eff/ is defined here, which contains both collective and alignment effects. Both of these can be measured in continuum ..gamma..-ray spectra of rotational nuclei up to high frequencies. The evolution of ..gamma..-ray spectra for Er nuclei from mass 160 to 154 shows that shell effects can directly be observed in the spectra of the lighter nuclei.

Deleplanque, M.A.

1982-10-01

164

Dependence of nuclear spin singlet lifetimes on RF spin-locking power  

E-print Network

We measure the lifetime of long-lived nuclear spin singlet states as a function of the strength of the RF spin-locking field and present a simple theoretical model that agrees well with our measurements, including the low-RF-power regime. We also measure the lifetime of a long-lived coherence between singlet and triplet states that does not require a spin-locking field for preservation. Our results indicate that for many molecules, singlet states can be created using weak RF spin-locking fields: more than two orders of magnitude lower RF power than in previous studies. Our findings suggest that in many biomolecules, singlets and related states with enhanced lifetimes might be achievable in vivo with safe levels of RF power.

Stephen J. DeVience; Ronald L. Walsworth; Matthew S. Rosen

2012-01-06

165

Fluorescence and spin properties of defects in single digit nanodiamonds.  

PubMed

This article reports stable photoluminescence and high-contrast optically detected electron spin resonance (ODESR) from single nitrogen-vacancy (NV) defect centers created within ultrasmall, disperse nanodiamonds of radius less than 4 nm. Unexpectedly, the efficiency for the production of NV fluorescent defects by electron irradiation is found to be independent of the size of the nanocrystals. Fluorescence lifetime imaging shows lifetimes with a mean value of around 17 ns, only slightly longer than the bulk value of the defects. After proper surface cleaning, the dephasing times of the electron spin resonance in the nanocrystals approach values of some microseconds, which is typical for the type Ib diamond from which the nanoparticle is made. We conclude that despite the tiny size of these nanodiamonds the photoactive nitrogen-vacancy color centers retain their bulk properties to the benefit of numerous exciting potential applications in photonics, biomedical labeling, and imaging. PMID:21452865

Tisler, Julia; Balasubramanian, Gopalakrishnan; Naydenov, Boris; Kolesov, Roman; Grotz, Bernhard; Reuter, Rolf; Boudou, Jean-Paul; Curmi, Patrick A; Sennour, Mohamed; Thorel, Alain; Börsch, Michael; Aulenbacher, Kurt; Erdmann, Rainer; Hemmer, Philip R; Jelezko, Fedor; Wrachtrup, Jörg

2009-07-28

166

Transverse single spin asymmetry in hadronic ?c,b production  

NASA Astrophysics Data System (ADS)

We study the transverse single spin asymmetry in ?c,b production in polarized hadron collisions, employing the collinear twist-3 approach in combination with the color singlet model. Our main focus lies on the contribution from the twist-3 Efremov-Teryaev-Qiu-Sterman function. By extrapolating the derived spin-dependent cross section to the small transverse momentum region, consistency between the collinear twist-3 approach and the transverse-momentum-dependent factorization approach is confirmed. As a byproduct of this work, we identify a term contributing to the scale evolution of trigluon correlations in the flavor-singlet case which was originally missed, see also V. M. Braun, A. N. Manashov, and B. Pirnay [Phys. Rev. D 80, 114002 (2009); PRVDAQ1550-799886, 119902(E) (2012)].

Schäfer, Andreas; Zhou, Jian

2013-07-01

167

Giant Spin Hall Effect in Single Photon Plasmonics  

E-print Network

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.

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

2012-12-24

168

Dynamics of Overhauser Field under nuclear spin diffusion in a quantum dot  

E-print Network

The coherence of electron spin can be significantly enhanced by locking the Overhauser field from nuclear spins using the nuclear spin preparation. We propose a theoretical model to calculate the long time dynamics of the Overhauser field under intrinsic nuclear spin diffusion in a quantum dot. We obtain a simplified diffusion equation that can be numerically solved and show quantitatively how the Knight shift and the electron-mediated nuclear spin flip-flop affect the nuclear spin diffusion. The results explain several recent experimental observations, where the decay time of Overhauser field is measured under different configurations, including variation of the external magnetic field, the electron spin configuration in a double dot, and the initial nuclear spin polarization rate.

Zhe-Xuan Gong; Zhang-qi Yin; L. -M. Duan

2009-12-22

169

Investigation of the Possibility of Using Nuclear Magnetic Spin Alignment  

NASA Technical Reports Server (NTRS)

The goal of the program to investigate a "Gasdynamic fusion propulsion system for space exploration" is to develop a fusion propulsion system for a manned mission to the planet mars. A study using Deuterium and Tritium atoms are currently in progress. When these atoms under-go fusion, the resulting neutrons and alpha particles are emitted in random directions (isotropically). The probable direction of emission is equal for all directions, thus resulting in wasted energy, massive shielding and cooling requirements, and serious problems with the physics of achieving fusion. If the nuclear magnetic spin moments of the deuterium and tritium nuclei could be precisely aligned at the moment of fusion, the stream of emitted neutrons could be directed out the rear of the spacecraft for thrust and the alpha particles directed forward into an electromagnet ot produce electricity to continue operating the fusion engine. The following supporting topics are discussed: nuclear magnetic moments and spin precession in magnetic field, nuclear spin quantum mechanics, kinematics of nuclear reactions, and angular distribution of particles.

Dent, William V., Jr.

1998-01-01

170

Observation of Spin-Orbit Splitting in ? Single-Particle States  

NASA Astrophysics Data System (ADS)

The spin-orbit splitting of ? single-particle states in 13?C was measured. The 13C\\(K-,?- \\)13?C reaction was used to excite both the 1/2- and 3/2- states simultaneously, which have predominantly 12C\\(0+\\)×p? configuration. ? rays from the states to the ground state were measured in coincidence with the ?-'s, by which ls splitting was found to be 152+/-54\\(stat\\)+/-36\\(syst\\) keV. The value is 20-30 times smaller than exhibited by the ls splitting in the nuclear shell model. This value gives us new insight into the YN interaction.

Ajimura, S.; Hayakawa, H.; Kishimoto, T.; Kohri, H.; Matsuoka, K.; Minami, S.; Mori, T.; Morikubo, K.; Saji, E.; Sakaguchi, A.; Shimizu, Y.; Sumihama, M.; Chrien, R. E.; May, M.; Pile, P.; Rusek, A.; Sutter, R.; Eugenio, P.; Franklin, G.; Khaustov, P.; Paschke, K.; Quinn, B. P.; Schumacher, R. A.; Franz, J.; Fukuda, T.; Noumi, H.; Outa, H.; Gan, L.; Tang, L.; Yuan, L.; Tamura, H.; Nakano, J.; Tamagawa, T.; Tanida, K.; Sawafta, R.

2001-05-01

171

Single Spin Asymmetry in High Pt Charged Hadron Production off Nuclei at 40 GeV  

E-print Network

The single transverse spin asymmetry data for the charged hadron production in pC and pCu interactions are presented. The measurements have been performed at FODS-2 experimental setup using 40 GeV/c IHEP polarized proton beam. The hadron transverse momentum range is from 0.5 GeV/c up to 4 GeV/c. The data obtained off the nuclear targets are compared with the proton target data measured earlier with the same experimental setup and with the data of other experiments.

V. V. Abramov; P. I. Goncharov; A. Yu. Kalinin; A. V. Khmelnikov; A. V. Korablev; Yu . P. Korneev; A. V. Kostritsky; A. N. Krinitsyn; V. I. Kryshkin; A. A. Markov; V. V. Talov; L. K. Turchanovich; A. A. Volkov

2004-12-29

172

Room-temperature high-speed nuclear-spin quantum memory in diamond  

E-print Network

Quantum memories provide intermediate storage of quantum information until it is needed for the next step of a quantum algorithm or a quantum communication process. Relevant figures of merit are therefore the fidelity with which the information can be written and retrieved, the storage time, and also the speed of the read-write process. Here, we present experimental data on a quantum memory consisting of a single $^{13}$C nuclear spin that is strongly coupled to the electron spin of a nitrogen-vacancy (NV) center in diamond. The strong hyperfine interaction of the nearest-neighbor carbon results in transfer times of 300 ns between the register qubit and the memory qubit, with an overall fidelity of 88 % for the write - storage - read cycle. The observed storage times of 3.3 ms appear to be limited by the T$_1$ relaxation of the electron spin. We discuss a possible scheme that may extend the storage time beyond this limit.

J. H. Shim; I. Niemeyer; J. Zhang; D. Suter

2013-01-03

173

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)

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.

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

2015-01-01

174

RF instrumentation and system design for coherent control of anisotropic hyperfine-coupled electron/nuclear spin qubits  

E-print Network

Coherent control is a fundamental challenge in quantum information processing (QIP). Our system of interest employs a local, isolated electron spin to coherently control nuclear spins. Coupled electron/nuclear spins are a ...

Abutaleb, Mohamed Osama

2010-01-01

175

Single cell elemental analysis using nuclear microscopy  

NASA Astrophysics Data System (ADS)

The use of Particle Induced X-ray Emission (PIXE), Rutherford Backscattering Spectrometry (RBS) and Scanning Transmission Ion Microscopy (STIM) to provide quantitative elemental analysis of single cells is an area which has high potential, particularly when the trace elements such as Ca, Fe, Zn and Cu can be monitored. We describe the methodology of sample preparation for two cell types, the procedures of cell imaging using STIM, and the quantitative elemental analysis of single cells using RBS and PIXE. Recent work on single cells at the Nuclear Microscopy Research Centre,National University of Singapore has centred around two research areas: (a) Apoptosis (programmed cell death), which has been recently implicated in a wide range of pathological conditions such as cancer, Parkinson's disease etc, and (b) Malaria (infection of red blood cells by the malaria parasite). Firstly we present results on the elemental analysis of human Chang liver cells (ATTCC CCL 13) where vanadium ions were used to trigger apoptosis, and demonstrate that nuclear microscopy has the capability of monitoring vanadium loading within individual cells. Secondly we present the results of elemental changes taking place in individual mouse red blood cells which have been infected with the malaria parasite and treated with the anti-malaria drug Qinghaosu (QHS).

Ren, M. Q.; Thong, P. S. P.; Kara, U.; Watt, F.

1999-04-01

176

Giant optical Faraday rotation induced by a single electron spin in a quantum dot: Applications to entangling remote spins via a single photon  

E-print Network

We propose a quantum non-demolition method - giant Faraday rotation - to detect a single electron spin in a quantum dot inside a microcavity where negatively-charged exciton strongly couples to the cavity mode. Left- and right-circularly polarized light reflected from the cavity feels different phase shifts due to cavity quantum electrodynamics and the optical spin selection rule. This yields giant and tunable Faraday rotation which can be easily detected experimentally. Based on this spin-detection technique, a scalable scheme to create an arbitrary amount of entanglement between two or more remote spins via a single photon is proposed.

C. Y. Hu; A. Young; J. L. O'Brien; J. G. Rarity

2008-03-08

177

Observation of spin-charge conversion in chemical-vapor-deposition-grown single-layer graphene  

NASA Astrophysics Data System (ADS)

Conversion of pure spin current to charge current in single-layer graphene (SLG) is investigated by using spin pumping. Large-area SLG grown by chemical vapor deposition is used for the conversion. Efficient spin accumulation in SLG by spin pumping enables observing an electromotive force produced by the inverse spin Hall effect (ISHE) of SLG. The spin Hall angle of SLG is estimated to be 6.1 × 10-7. The observed ISHE in SLG is ascribed to its non-negligible spin-orbit interaction in SLG.

Ohshima, Ryo; Sakai, Atsushi; Ando, Yuichiro; Shinjo, Teruya; Kawahara, Kenji; Ago, Hiroki; Shiraishi, Masashi

2014-10-01

178

Coherent manipulation of an NV center and one carbon nuclear spin  

NASA Astrophysics Data System (ADS)

We study a three-qubit system formed by the NV center's electronic and nuclear spin plus an adjacent spin 1/2 carbon 13C . Specifically, we propose a manipulation scheme utilizing the hyperfine coupling of the effective S=1 degree of freedom of the vacancy electrons to the two adjacent nuclear spins to achieve accurate coherent control of all three qubits.

Scharfenberger, Burkhard; Munro, William J.; Nemoto, Kae

2014-12-01

179

Manipulation of the nuclear spin ensemble in a quantum dot with chirped magnetic resonance pulses  

NASA Astrophysics Data System (ADS)

The nuclear spins in nanostructured semiconductors play a central role in quantum applications. The nuclear spins represent a useful resource for generating local magnetic fields but nuclear spin noise represents a major source of dephasing for spin qubits. Controlling the nuclear spins enhances the resource while suppressing the noise. NMR techniques are challenging: the group III and V isotopes have large spins with widely different gyromagnetic ratios; in strained material there are large atom-dependent quadrupole shifts; and nanoscale NMR is hard to detect. We report NMR on 100,000 nuclear spins of a quantum dot using chirped radiofrequency pulses. Following polarization, we demonstrate a reversal of the nuclear spin. We can flip the nuclear spin back and forth a hundred times. We demonstrate that chirped NMR is a powerful way of determining the chemical composition, the initial nuclear spin temperatures and quadrupole frequency distributions for all the main isotopes. The key observation is a plateau in the NMR signal as a function of sweep rate: we achieve inversion at the first quantum transition for all isotopes simultaneously. These experiments represent a generic technique for manipulating nanoscale inhomogeneous nuclear spin ensembles and open the way to probe the coherence of such mesoscopic systems.

Munsch, Mathieu; Wüst, Gunter; Kuhlmann, Andreas V.; Xue, Fei; Ludwig, Arne; Reuter, Dirk; Wieck, Andreas D.; Poggio, Martino; Warburton, Richard J.

2014-09-01

180

Nuclear states and shapes at high spin. [Good review  

SciTech Connect

As angular momentum is added to a nucleus, the balance of forces acting upon it to determine its shape, moment of inertia, mode of rotation, and type of level structure may undergo a series of changes. At relatively low spins a deformed nucleus will rotate collectively, and one may see the effect of Coriolis antipairing in gradually increasing the moment of inertia. Around spin 12 to 16 h-bar there may be an abrupt change (backbending) when a pair of high-j nucleons unpairs and the nucleons align with the axis of rotation; this process allows the nucleus to slow its collective rotation. This process, the start of a sharing of angular momentum between single-particle motion and the collective rotation, gives a lower total energy and corresponds to a change toward triaxiality in the shape of the nucleus. At much higher spins discrete ..gamma..-ray transitions can no longer be observed. This is the regime of continuum spectra; all the information on these high-spin states (to 65 h-bar) is contained in these continuum cascades. Knowledge is accumulating on how to study these spectra, experimentally and theoretically, and new techniques offer promise of revealing a great deal of information about the shapes and properties of very high spin states. 71 references, 34 figures.

Diamond, R.M.

1980-08-01

181

Evidence Of An Incommensurate Spin-Density Wave Instability In Single Crystal Bafe2as Detected By 75as NMR  

SciTech Connect

We report a {sup 75}As NMR study of BaFe{sub 2}As{sub 2} in both single crystal and polycrystal forms. The temperature dependence of the {sup 75}As NMR spectra shows magnetic broadening associated with a spin-density-wave instability at 85 K for the single crystal and at 138 K for the polycrystal material. The nuclear spin-lattice relaxation rate T{sub 1}{sup -1} exhibits a sharp maximum at the transition and is independent of field orientation in the single crystal. Our study suggests that there is no significant difference in the physics of single crystal and polycrystal BaFe{sub 2}As{sub 2} even though some properties differ qualitatively.

Baek, Seung H [Los Alamos National Laboratory; Klimczuk, Tomasz W [Los Alamos National Laboratory; Ronning, Filip [Los Alamos National Laboratory; Bauer, Eric D [Los Alamos National Laboratory; Thompson, Joe D [Los Alamos National Laboratory; Curro, Nicholas J [UC-DAVIS

2008-01-01

182

Spin-dependent thermoelectronic transport of a single molecule magnet Mn(dmit){sub 2}  

SciTech Connect

We investigate spin-dependent thermoelectronic transport properties of a single molecule magnet Mn(dmit){sub 2} sandwiched between two Au electrodes using first-principles density functional theory combined with nonequilibrium Green's function method. By applying a temperature difference between the two Au electrodes, spin-up and spin-down currents flowing in opposite directions can be induced due to asymmetric distribution of the spin-up and spin-down transmission spectra around the Fermi level. A pure spin current and 100% spin polarization are achieved by tuning back-gate voltage to the system. The spin caloritronics of the molecule with a perpendicular conformation is also explored, where the spin-down current is blocked strongly. These results suggest that Mn(dmit){sub 2} is a promising material for spin caloritronic applications.

Su, Zhongbo; Wei, Xinyuan; Yang, Zhongqin, E-mail: zyang@fudan.edu.cn [State Key Laboratory of Surface Physics and Key Laboratory for Computational Physical Sciences (MOE) and Department of Physics, Fudan University, Shanghai 200433 (China); An, Yipeng [College of Physics and Electronic Engineering and Institute of Computational Materials Design, Henan Normal University, Xinxiang 453007 (China)

2014-05-28

183

Solid effect in magic angle spinning dynamic nuclear polarization  

NASA Astrophysics Data System (ADS)

For over five decades, the solid effect (SE) has been heavily utilized as a mechanism for performing dynamic nuclear polarization (DNP). Nevertheless, it has not found widespread application in contemporary, high magnetic field DNP experiments because SE enhancements display an ? _0 ^{ - 2} field dependence. In particular, for nominally forbidden zero and double quantum SE transitions to be partially allowed, it is necessary for mixing of adjacent nuclear spin states to occur, and this leads to the observed field dependence. However, recently we have improved our instrumentation and report here an enhancement of ? = 91 obtained with the organic radical trityl (OX063) in magic angle spinning experiments performed at 5 T and 80 K. This is a factor of 6-7 higher than previous values in the literature under similar conditions. Because the solid effect depends strongly on the microwave field strength, we attribute this large enhancement to larger microwave field strengths inside the sample volume, achieved with more efficient coupling of the gyrotron to the sample chamber. In addition, we develop a theoretical model to explain the dependence of the buildup rate of enhanced nuclear polarization and the steady-state enhancement on the microwave power. Buildup times and enhancements were measured as a function of 1H concentration for both trityl and Gd-DOTA. Comparison of the results indicates that for trityl the initial polarization step is the slower, rate-determining step. However, for Gd-DOTA the spread of nuclear polarization via homonuclear 1H spin diffusion is rate-limiting. Finally, we discuss the applicability of the solid effect at fields > 5 T and the requirements to address the unfavorable field dependence of the solid effect.

Corzilius, Björn; Smith, Albert A.; Griffin, Robert G.

2012-08-01

184

Solid effect in magic angle spinning dynamic nuclear polarization.  

PubMed

For over five decades, the solid effect (SE) has been heavily utilized as a mechanism for performing dynamic nuclear polarization (DNP). Nevertheless, it has not found widespread application in contemporary, high magnetic field DNP experiments because SE enhancements display an ?(0)(-2) field dependence. In particular, for nominally forbidden zero and double quantum SE transitions to be partially allowed, it is necessary for mixing of adjacent nuclear spin states to occur, and this leads to the observed field dependence. However, recently we have improved our instrumentation and report here an enhancement of ? = 91 obtained with the organic radical trityl (OX063) in magic angle spinning experiments performed at 5 T and 80 K. This is a factor of 6-7 higher than previous values in the literature under similar conditions. Because the solid effect depends strongly on the microwave field strength, we attribute this large enhancement to larger microwave field strengths inside the sample volume, achieved with more efficient coupling of the gyrotron to the sample chamber. In addition, we develop a theoretical model to explain the dependence of the buildup rate of enhanced nuclear polarization and the steady-state enhancement on the microwave power. Buildup times and enhancements were measured as a function of (1)H concentration for both trityl and Gd-DOTA. Comparison of the results indicates that for trityl the initial polarization step is the slower, rate-determining step. However, for Gd-DOTA the spread of nuclear polarization via homonuclear (1)H spin diffusion is rate-limiting. Finally, we discuss the applicability of the solid effect at fields > 5 T and the requirements to address the unfavorable field dependence of the solid effect. PMID:22894339

Corzilius, Björn; Smith, Albert A; Griffin, Robert G

2012-08-01

185

Single-spin precessing gravitational waveform in closed form  

NASA Astrophysics Data System (ADS)

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.

Lundgren, Andrew; O'Shaughnessy, R.

2014-02-01

186

Investigation of a new model of dipolar-coupled nuclear spin relaxation and applications of dynamic nuclear polarization  

NASA Astrophysics Data System (ADS)

This work presents the results of various investigations using various techniques of hyperpolarizing the nuclei of atoms. Hyperpolarization implies magnetic order in excess of the thermal order obtained naturally as described by Curie's law. The main portion of this work presents the results of a detailed experimental exploration of predictions arising from a new model of transverse nuclear spin relaxation in quantum systems, based on possible manifestations of microscopic chaos in quantum systems. Experiments have been carried out on a number of hyperpolarized xenon samples, each differing in its relative percentage of xenon isotopes in order to vary the homonuclear and heteronuclear dipole couplings in the spin system. The experiments were performed under a variety of conditions in an attempt to observe the behaviors predicted by the model. Additionally, much more extensive measurements were made on a number of samples of solid CaF2 in both single crystal and powder forms. These samples, although thermally polarized, were observed with superior signal to noise ratios than even the hyperpolarized xenon solids, allowing for more precise measurements for comparison to the theory. This work thus contains the first experimental evidence for the majority of the model's predictions. Additionally, this work contains the first precise measurements of the frequency-shift enhancement parameters for 129Xe and krypton in the presence of spin-polarized Rb. The determination of these important numbers will be useful to many groups who utilize spin-exchange optical pumping in their labs. This work built on the prior knowledge of a precise number for the frequency-shift enhancement parameter of 3He in Rb vapor. Finally, I detail work using NMR to detect nuclear-spin polarization enhancement in silicon phosphorus by a novel, photo-induced hyperpolarization technique developed by the Boehme research group at the University of Utah. Significant nuclear polarization enhancements were observed by the Boehme group due to electron-photon interactions in semiconductor soilds; these enhancements were observed by their effects on the ambient electrons and measured with electron spin resonance techniques. The work described here details experiments to observe the enhanced nuclear polarization by directly measuring the intensity increase in an NMR measurement. I will conclude this dissertation with a brief appendix giving a summary of one additional project involving the use of high pressure fluorinated gas NMR to measure the internal topology and characteristics of energy-rich oil shales.

Sorte, Eric G.

187

High spin single particle states in 152,153Er  

NASA Astrophysics Data System (ADS)

A spectroscopic investigation of yrast and near-yrast states in 152Er and 153Er is presented. We report measurements of prompt and delayed excitation functions, ?-? coincidences, isomeric lifetimes, and ?-ray angular distribution, obtained chiefly from the reactions 144Sm(12C,xn)152,153Er using carbon beams of laboratory energy 65-95 MeV. The levels observed extend to a spin of J>=432 and include two long-lived isomers in 153Er. The nuclear structure is discussed in terms of the shell model and compared with the systematic behavior of levels in N=84 and N=85 isotones. NUCLEAR REACTIONS 144Sm(12C,xn) E=65-95 MeV; 144Sm(11B,xn) E=40-70 MeV; 124Te(32S,xn) E=125-155 MeV. Measured I?(E,t), I?(?), ?-?(t). Deduced level sequences, T12, J?. Continuous and pulsed beams, enriched targets, Ge(Li) detectors, NaI(Tl) multiplicity filter.

Horn, D.; Young, G. R.; Lister, C. J.; Baktash, C.

1981-03-01

188

Single-spin azimuthal asymmetry in exclusive electroproduction of ?+ mesons  

NASA Astrophysics Data System (ADS)

A single-spin asymmetry in the distribution of exclusively produced ?+ mesons azimuthally around the virtual photon direction relative to the lepton scattering plane has been measured for the first time in deep-inelastic scattering of positrons off longitudinally polarized protons. Integrated over the experimental acceptance, the /sin? moment of the polarization asymmetry of the cross section is measured to be /-0.18+/-0.05(stat.)+/-0.02(syst.). The asymmetry is also studied as a function of the relevant kinematic variables, and its magnitude is found to grow with decreasing /x and increasing /-t and vanish at t-->tmin (where /x is the Bjorken scaling variable and /t is the squared four-momentum transferred to the nucleon).

HERMES Collaboration; Airapetian, A.; Akopov, N.; Akopov, Z.; Amarian, M.; Aschenauer, E. C.; Avakian, H.; Avakian, R.; Avetissian, A.; Avetissian, E.; Bailey, P.; Baturin, V.; Baumgarten, C.; Beckmann, M.; Belostotski, S.; Bernreuther, S.; Bianchi, N.; Böttcher, H.; Borissov, A.; Bouhali, O.; Bouwhuis, M.; Brack, J.; Brauksiepe, S.; Brüll, A.; Brunn, I.; Bulten, H. J.; Capitani, G. P.; Chumney, P.; Cisbani, E.; Ciullo, G.; Court, G. R.; Dalpiaz, P. F.; De Leo, R.; De Nardo, L.; De Sanctis, E.; De Schepper, D.; Devitsin, E.; de Witt Huberts, P. K. A.; Di Nezza, P.; Düren, M.; Ehrenfried, M.; Elbakian, G.; Ellinghaus, F.; Ely, J.; Fabbri, R.; Fantoni, A.; Fechtchenko, A.; Felawka, L.; Filippone, B. W.; Fischer, H.; Fox, B.; Franz, J.; Frullani, S.; Gärber, Y.; Garibaldi, F.; Garutti, E.; Gavrilov, G.; Gharibyan, V.; Graw, G.; Grebeniouk, O.; Green, P. W.; Greeniaus, L. G.; Gute, A.; Haeberli, W.; Hafidi, K.; Hartig, M.; Hasch, D.; Heesbeen, D.; Heinsius, F. H.; Henoch, M.; Hertenberger, R.; Hesselink, W. H. A.; Hofman, G.; Holler, Y.; Holt, R. J.; Hommez, B.; Iarygin, G.; Izotov, A.; Jackson, H. E.; Jgoun, A.; Jung, P.; Kaiser, R.; Kisselev, A.; Kitching, P.; Königsmann, K.; Kolster, H.; Korotkov, V.; Kotik, E.; Kozlov, V.; Krauss, B.; Krivokhijine, V. G.; Kyle, G.; Lagamba, L.; Laziev, A.; Lenisa, P.; Liebing, P.; Lindemann, T.; Lorenzon, W.; Maas, A.; Makins, N. C. R.; Marukyan, H.; Masoli, F.; McIlhany, K.; Meissner, F.; Menden, F.; Mexner, V.; Meyners, N.; Mikloukho, O.; Milner, R.; Muccifora, V.; Nagaitsev, A.; Nappi, E.; Naryshkin, Y.; Nass, A.; Negodaeva, K.; Nowak, W.-D.; Oganessyan, K.; O'Neill, T. G.; Owen, B. R.; Pate, S. F.; Podiatchev, S.; Potashov, S.; Potterveld, D. H.; Raithel, M.; Rakness, G.; Rappoport, V.; Redwine, R.; Reggiani, D.; Reimer, P.; Reolon, A. R.; Rith, K.; Robinson, D.; Rostomyan, A.; Ryckbosch, D.; Sakemi, Y.; Sanjiev, I.; Sato, F.; Savin, I.; Scarlett, C.; Schäfer, A.; Schill, C.; Schmidt, F.; Schnell, G.; Schüler, K. P.; Schwind, A.; Seibert, J.; Seitz, B.; Shibata, T.-A.; Shutov, V.; Simani, M. C.; Simon, A.; Sinram, K.; Steffens, E.; Steijger, J. J. M.; Stewart, J.; Stösslein, U.; Suetsugu, K.; Taroian, S.; Terkulov, A.; Tessarin, S.; Thomas, E.; Tipton, B.; Tytgat, M.; Urciuoli, G. M.; van den Brand, J. F. J.; van der Steenhoven, G.; van de Vyver, R.; Vetterli, M. C.; Vikhrov, V.; Vincter, M. G.; Visser, J.; Volmer, J.; Weiskopf, C.; Wendland, J.; Wilbert, J.; Wise, T.; Yen, S.; Yoneyama, S.; Zohrabian, H.

2002-05-01

189

Calculation of TMD Evolution for Transverse Single Spin Asymmetry Measurements  

SciTech Connect

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.

Mert Aybat, Ted Rogers, Alexey Prokudin

2012-06-01

190

Global fitting of single spin asymmetry: An attempt  

NASA Astrophysics Data System (ADS)

We present an attempt of global analysis of semi-inclusive deep inelastic scattering ?p???'?X data on single spin asymmetries and data on left-right asymmetry AN in p?p??X in order to simultaneously extract information on the Sivers function and the twist-three quark-gluon Efremov-Teryaev-Qiu-Sterman function. We explore different possibilities such as the node of the Sivers function in x or k? in order to explain “sign mismatch” between these functions. We show that ?± semi-inclusive deep inelastic scattering data and ?0 STAR data can be well described in a combined fit based on both the transverse momentum dependent and collinear twist-three factorization formalisms; however, ?± BRAHMS data are not described in a satisfactory way. This leaves the question open of a solution to the “sign mismatch.” Possible explanations are then discussed.

Kang, Zhong-Bo; Prokudin, Alexei

2012-04-01

191

Nuclear Spin Maser at Highly Stabilized Low Magnetic Field and Search for Atomic EDM  

SciTech Connect

A nuclear spin maser is operated at a low static field through an active feedback scheme based on an optical nuclear spin detection and succeeding spin control by a transverse field application. The frequency stability of this optical-coupling spin maser is improved by installation of a low-noise current source for a solenoid magnet producing a static magnetic field in the maser operation. Experimental devices for application of the maser to EDM experiment are being developed.

Yoshimi, A. [RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Asahi, K.; Inoue, T.; Uchida, M.; Hatakeyama, N.; Tsuchiya, M.; Kagami, S. [Department of Physics, Tokyo Institute of Technology, Oh-okayama 2-12-1, Meguro, Tokyo 152-8551 (Japan)

2009-08-04

192

Hyperfine Interactions 127 (2000) 395398 395 Manifestation of nuclear spin-dependent P-odd  

E-print Network

Hyperfine Interactions 127 (2000) 395­398 395 Manifestation of nuclear spin-dependent P-odd Nuclear Physics Institute, 188350 Gatchina, Leningrad district, Russia E-mail: porsev@thd.pnpi.spb.ru P-odd effects caused by the nuclear spin-dependent electron­nucleon interaction are con- sidered. P-odd

Kozlov, Mikhail G

193

Nuclear Hydrogen for Peak Electricity Production and Spinning Reserve  

SciTech Connect

Nuclear energy can be used to produce hydrogen. The key strategic question is this: ''What are the early markets for nuclear hydrogen?'' The answer determines (1) whether there are incentives to implement nuclear hydrogen technology today or whether the development of such a technology could be delayed by decades until a hydrogen economy has evolved, (2) the industrial partners required to develop such a technology, and (3) the technological requirements for the hydrogen production system (rate of production, steady-state or variable production, hydrogen purity, etc.). Understanding ''early'' markets for any new product is difficult because the customer may not even recognize that the product could exist. This study is an initial examination of how nuclear hydrogen could be used in two interconnected early markets: the production of electricity for peak and intermediate electrical loads and spinning reserve for the electrical grid. The study is intended to provide an initial description that can then be used to consult with potential customers (utilities, the Electric Power Research Institute, etc.) to better determine the potential real-world viability of this early market for nuclear hydrogen and provide the starting point for a more definitive assessment of the concept. If this set of applications is economically viable, it offers several unique advantages: (1) the market is approximately equivalent in size to the existing nuclear electric enterprise in the United States, (2) the entire market is within the utility industry and does not require development of an external market for hydrogen or a significant hydrogen infrastructure beyond the utility site, (3) the technology and scale match those of nuclear hydrogen production, (4) the market exists today, and (5) the market is sufficient in size to justify development of nuclear hydrogen production techniques independent of the development of any other market for hydrogen. These characteristics make it an ideal early market for nuclear hydrogen.

Forsberg, C.W.

2005-01-20

194

DFT studies of spin-electric effects in single-molecule magnets without inversion symmetry  

Microsoft Academic Search

Recently [1] it has been proposed that in single-molecule magnets (SMMs) lacking inversion symmetry, a mechanism based on the interplay among quantum exchange, spin orbit interaction and chirality of the underlying spin texture, allows for an effective coupling between the spin states and an external electric field. This effect could represent a very efficient and fast way of manipulating the

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

2010-01-01

195

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

E-print Network

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...

Shin, Chang-Seok

2009-05-15

196

Coherent spin transport and suppression of spin relaxation in InSb nanowires with single subband occupancy at room temperature.  

PubMed

A longstanding goal of spintronics is to inject, then coherently transport, and finally detect electron spins in a semiconductor nanowire in which a single quantized subband is occupied by the electrons at room temperature. Here, the achieving of this goal in electrochemically self-assembled 50-nm diameter InSb nanowires is reported and substantiated by demonstrating both the spin-valve effect and the Hanle effect. Observing both effects in the same sample allows one to estimate the electron mobility and the spin relaxation time in the nanowires. It is found that despite four orders of magnitude degradation in the mobility compared to bulk or quantum wells and a resulting four orders of magnitude increase in the Elliott-Yafet spin relaxation rate, the spin relaxation time in the nanowires is still about an order of magnitude longer than what has been reported in bulk and quantum wells. This is caused by the elimination or suppression of the D'yakonov-Perel' spin relaxation through single subband occupancy. These experiments shed light on the nature of spin transport in a true quantum wire and raise hopes for the realization of a room-temperature Datta-Das spin transistor, where single subband occupancy is critical for optimum performance. PMID:25048330

Bandyopadhyay, Saumil; Hossain, Md Iftekhar; Ahmad, Hasnain; Atulasimha, Jayasimha; Bandyopadhyay, Supriyo

2014-11-12

197

Suppression of nuclear spin bath fluctuations in self-assembled quantum dots induced by inhomogeneous strain  

NASA Astrophysics Data System (ADS)

Interaction with nuclear spins leads to decoherence and information loss in solid-state electron-spin qubits. One particular, ineradicable source of electron decoherence arises from decoherence of the nuclear spin bath, driven by nuclear–nuclear dipolar interactions. Owing to its many-body nature nuclear decoherence is difficult to predict, especially for an important class of strained nanostructures where nuclear quadrupolar effects have a significant but largely unknown impact. Here, we report direct measurement of nuclear spin bath coherence in individual self-assembled InGaAs/GaAs quantum dots: spin-echo coherence times in the range 1.2–4.5?ms are found. Based on these values, we demonstrate that strain-induced quadrupolar interactions make nuclear spin fluctuations much slower compared with lattice-matched GaAs/AlGaAs structures. Our findings demonstrate that quadrupolar effects can potentially be used to engineer optically active III-V semiconductor spin-qubits with a nearly noise-free nuclear spin bath, previously achievable only in nuclear spin-0 semiconductors, where qubit network interconnection and scaling are challenging.

Chekhovich, E. A.; Hopkinson, M.; Skolnick, M. S.; Tartakovskii, A. I.

2015-02-01

198

Suppression of nuclear spin bath fluctuations in self-assembled quantum dots induced by inhomogeneous strain  

PubMed Central

Interaction with nuclear spins leads to decoherence and information loss in solid-state electron-spin qubits. One particular, ineradicable source of electron decoherence arises from decoherence of the nuclear spin bath, driven by nuclear–nuclear dipolar interactions. Owing to its many-body nature nuclear decoherence is difficult to predict, especially for an important class of strained nanostructures where nuclear quadrupolar effects have a significant but largely unknown impact. Here, we report direct measurement of nuclear spin bath coherence in individual self-assembled InGaAs/GaAs quantum dots: spin-echo coherence times in the range 1.2–4.5?ms are found. Based on these values, we demonstrate that strain-induced quadrupolar interactions make nuclear spin fluctuations much slower compared with lattice-matched GaAs/AlGaAs structures. Our findings demonstrate that quadrupolar effects can potentially be used to engineer optically active III-V semiconductor spin-qubits with a nearly noise-free nuclear spin bath, previously achievable only in nuclear spin-0 semiconductors, where qubit network interconnection and scaling are challenging. PMID:25704639

Chekhovich, E.A.; Hopkinson, M.; Skolnick, M.S.; Tartakovskii, A.I.

2015-01-01

199

Stable Three-Axis Nuclear Spin Gyroscope in Diamond  

E-print Network

We propose a sensitive and stable three-axis gyroscope in diamond. We achieve high sensitivity by exploiting the long coherence time of the N14 nuclear spin associated with the Nitrogen-Vacancy center in diamond, and the efficient polarization and measurement of its electronic spin. While the gyroscope is based on a simple Ramsey interferometry scheme, we use coherent control of the quantum sensor to improve its coherence time as well as its robustness against long-time drifts, thus achieving a very robust device with a resolution of 0.5mdeg/s/(Hz mm^3)^(1/2). In addition, we exploit the four axes of delocalization of the Nitrogen-Vacancy center to measure not only the rate of rotation, but also its direction, thus obtaining a compact three-axis gyroscope.

Ajoy, Ashok

2012-01-01

200

Stable Three-Axis Nuclear Spin Gyroscope in Diamond  

E-print Network

We propose a sensitive and stable three-axis gyroscope in diamond. We achieve high sensitivity by exploiting the long coherence time of the N14 nuclear spin associated with the Nitrogen-Vacancy center in diamond, and the efficient polarization and measurement of its electronic spin. While the gyroscope is based on a simple Ramsey interferometry scheme, we use coherent control of the quantum sensor to improve its coherence time as well as its robustness against long-time drifts, thus achieving a very robust device with a resolution of 0.5mdeg/s/(Hz mm^3)^(1/2). In addition, we exploit the four axes of delocalization of the Nitrogen-Vacancy center to measure not only the rate of rotation, but also its direction, thus obtaining a compact three-axis gyroscope.

Ashok Ajoy; Paola Cappellaro

2012-05-07

201

Nuclear Magnetic Resonance (NMR) This technique observes signals from nuclear spins  

E-print Network

magnetic moment () The Bohr model of H atom electron Nucleus I I = n I An intrinsic property of the nucleus Why & how to observe nuclear spins? Can be though of as a strange tiny magnet () #12;Timeline I 1946) 1960s: Solid state NMR ­ Waugh NMR imaging was demonstrated 1975: Fourier Imaging ­ R. Ernst Timeline

Chen, Yang-Yuan

202

Nuclear spin conversion of water inside fullerene cages detected by low-temperature nuclear magnetic resonance  

SciTech Connect

The water-endofullerene H{sub 2}O@C{sub 60} provides a unique chemical system in which freely rotating water molecules are confined inside homogeneous and symmetrical carbon cages. The spin conversion between the ortho and para species of the endohedral H{sub 2}O was studied in the solid phase by low-temperature nuclear magnetic resonance. The experimental data are consistent with a second-order kinetics, indicating a bimolecular spin conversion process. Numerical simulations suggest the simultaneous presence of a spin diffusion process allowing neighbouring ortho and para molecules to exchange their angular momenta. Cross-polarization experiments found no evidence that the spin conversion of the endohedral H{sub 2}O molecules is catalysed by {sup 13}C nuclei present in the cages.

Mamone, Salvatore, E-mail: s.mamone@soton.ac.uk; Concistrè, Maria; Carignani, Elisa; Meier, Benno; Krachmalnicoff, Andrea; Johannessen, Ole G.; Denning, Mark; Carravetta, Marina; Whitby, Richard J.; Levitt, Malcolm H., E-mail: mhl@soton.ac.uk [School of Chemistry, University of Southampton, Southampton SO17 1BJ (United Kingdom); Lei, Xuegong; Li, Yongjun [Department of Chemistry, Columbia University, New York, New York 10027 (United States)] [Department of Chemistry, Columbia University, New York, New York 10027 (United States); Goh, Kelvin; Horsewill, Anthony J. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)] [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

2014-05-21

203

Role of electron-electron scattering on spin transport in single layer graphene  

SciTech Connect

In this work, the effect of electron-electron scattering on spin transport in single layer graphene is studied using semi-classical Monte Carlo simulation. The D’yakonov-P’erel mechanism is considered for spin relaxation. It is found that electron-electron scattering causes spin relaxation length to decrease by 35% at 300 K. The reason for this decrease in spin relaxation length is that the ensemble spin is modified upon an e-e collision and also e-e scattering rate is greater than phonon scattering rate at room temperature, which causes change in spin relaxation profile due to electron-electron scattering.

Ghosh, Bahniman, E-mail: bghosh@utexas.edu [Microelectronics Research Center, 10100, Burnet Road, Bldg. 160, University of Texas at Austin, Austin, TX, 78758 (United States)] [Microelectronics Research Center, 10100, Burnet Road, Bldg. 160, University of Texas at Austin, Austin, TX, 78758 (United States); Katiyar, Saurabh; Salimath, Akshaykumar, E-mail: salimath@iitk.ac.in [Department of Electrical Engineering, Indian Institute of Technology, Kanpur 208016 (India)] [Department of Electrical Engineering, Indian Institute of Technology, Kanpur 208016 (India)

2014-01-15

204

Quadrupolar spectra of nuclear spins in strained InGaAs quantum dots  

E-print Network

Self-assembled quantum dots (QDs) are born out of lattice mismatched ingredients where strain plays an indispensable role. Through the electric quadrupolar coupling, strain affects the magnetic environment as seen by the nuclear spins. To guide prospective single-QD nuclear magnetic resonance (NMR) as well as dynamic nuclear spin polarization experiments, an atomistic insight to the strain and quadrupolar field distributions is presented. A number of implications of the structural and compositional profile of the QD have been identified. A high aspect ratio of the QD geometry enhances the quadrupolar interaction. The inclined interfaces introduce biaxiality and the tilting of the major quadrupolar principal axis away from the growth axis; the alloy mixing of gallium into the QD enhances both of these features while reducing the quadrupolar energy. Regarding the NMR spectra, both Faraday and Voigt geometries are investigated, unraveling in the first place the extend of inhomogeneous broadening and the appearance of the normally-forbidden transitions. Moreover, it is shown that from the main extend of the NMR spectra the alloy mole fraction of a single QD can be inferred. By means of the element-resolved NMR intensities it is found that In nuclei has a factor of five dominance over those of As. In the presence of an external magnetic field, the borderlines between the quadrupolar and Zeeman regimes are extracted as 1.5 T for In and 1.1 T for As nuclei. At these values the nuclear spin depolarization rates of the respective nuclei get maximized due to the noncollinear secular hyperfine interaction with a resident electron in the QD.

Ceyhun Bulutay

2012-05-01

205

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

E-print Network

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.

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

2013-01-01

206

Estimation of optical chemical shift in nuclear spin optical rotation  

NASA Astrophysics Data System (ADS)

A recently proposed optical chemical shift in nuclear spin optical rotation (NSOR) is studied by theoretical comparison of NSOR magnitude between chemically non-equivalent or different element nuclei in the same molecule. Theoretical expressions of the ratio R between their NSOR magnitudes are derived by using a known semi-empirical formula of NSOR. Taking methanol, tri-ethyl-phosphite and 2-methyl-benzothiazole as examples, the ratios R are calculated and the results approximately agree with the experiments. Based on those, the important influence factors on R and chemical distinction by NSOR are discussed.

Chen, Fang; Yao, Guo-hua; He, Tian-jing; Chen, Dong-ming; Liu, Fan-chen

2014-05-01

207

Efficient room-temperature nuclear spin hyperpolarization of a defect atom in a semiconductor.  

PubMed

Nuclear spin hyperpolarization is essential to future solid-state quantum computation using nuclear spin qubits and in highly sensitive magnetic resonance imaging. Though efficient dynamic nuclear polarization in semiconductors has been demonstrated at low temperatures for decades, its realization at room temperature is largely lacking. Here we demonstrate that a combined effect of efficient spin-dependent recombination and hyperfine coupling can facilitate strong dynamic nuclear polarization of a defect atom in a semiconductor at room temperature. We provide direct evidence that a sizeable nuclear field (~150 Gauss) and nuclear spin polarization (~15%) sensed by conduction electrons in GaNAs originates from dynamic nuclear polarization of a Ga interstitial defect. We further show that the dynamic nuclear polarization process is remarkably fast and is completed in <5 ?s at room temperature. The proposed new concept could pave a way to overcome a major obstacle in achieving strong dynamic nuclear polarization at room temperature, desirable for practical device applications. PMID:23612292

Puttisong, Y; Wang, X J; Buyanova, I A; Geelhaar, L; Riechert, H; Ptak, A J; Tu, C W; Chen, W M

2013-01-01

208

NMR response of nuclear-spin helix in quantum wires with hyperfine and spin-orbit interaction  

NASA Astrophysics Data System (ADS)

We calculate the nuclear magnetic resonance (NMR) response of a quantum wire where at low temperature a self-sustained electron-nuclear spin order is created. Our model includes the electron mediated Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange, electron spin-orbit interactions, nuclear dipolar interactions, and the static and oscillating NMR fields, all of which play an essential role. The paramagnet to helimagnet transition in the nuclear system is reflected in an unusual response: it absorbs at a frequency given by the internal RKKY exchange field, rather than the external static field, whereas the latter leads to a splitting of the resonance peak.

Stano, Peter; Loss, Daniel

2014-11-01

209

Dynamics of entanglement of two electron spins interacting with nuclear spin baths in quantum dots  

E-print Network

We study the dynamics of entanglement of two electron spins in two quantum dots, in which each electron is interacting with its nuclear spin environment. Focusing on the case of uncoupled dots, and starting from either Bell or Werner states of two qubits, we calculate the decay of entanglement due to hyperfine interaction with the nuclei. We mostly focus on the regime of magnetic fields in which the bath-induced electron spin flips play a role, for example their presence leads to appearance of entanglement sudden death at finite time for two qubits initialized in a Bell state. For these fields the intra-bath dipolar interactions and inhomogeneity of hyperfine couplings are irrelevant on timescales of coherence (and entanglement) decay, and most of the presented calculations are performed using the uniform-coupling approximation to the exact hyperfine Hamiltonian. We provide a comprehensive overview of entanglement decay in this regime, considering both free evolution of the qubits, and an echo protocol with simultaneous application of $\\pi$ pulses to the two spins. All the currently experimentally relevant bath states are considered: the thermal state, narrowed states (characterized by diminished uncertainty of one of the components of the Overhauser field) for two uncorrelated baths, and a correlated narrowed state with well-defined value of the $z$ component of the Overhauser field interdot gradient. While we mostly use concurrence to quantify the amount of entanglement in a mixed state of the two electron spins, we also discuss the predicted behavior of currently experimentally relevant entanglement witnesses, and in particular we give results for quantum teleportation fidelity using a partially disentangled state as a resource.

Igor Bragar; ?ukasz Cywi?ski

2014-11-23

210

Efficient route to high-bandwidth nanoscale magnetometry using single spins in diamond.  

PubMed

Nitrogen-vacancy (NV) center in diamond is a promising quantum metrology tool finding applications across disciplines. The spin sensor measures magnetic fields, electric fields and temperature with nano-scale precision and is fully operable under ambient conditions. Moreover, it achieves precision scaling inversely with total measurement time ?B ? 1/T (Heisenberg scaling) rather than as the inverse of the square root of T, with ?B = ?T the Shot-Noise limit. This scaling can be achieved by means of phase estimation algorithms (PEAs), in combination with single-shot read-out. Despite their accuracy, the range of applicability of PEAs is limited to sensing single frequencies with negligible temporal fluctuations. Nuclear Magnetic Resonance (NMR) signals from molecules often contain multifrequency components and sensing them using PEA is ruled out. Here we propose an alternative method for precision magnetometry in frequency multiplexed signals via compressive sensing (CS) techniques focusing on nanoscale NMR. We show that CS can provide for precision scaling approximately as ?B ? 1/T, as well as for a 5-fold increase in sensitivity over dynamic-range gain, in addition to reducing the total number of resources required. We illustrate our method by taking model solid-state spectra of Glycine acquired under Magic Angle Spinning conditions. PMID:24728454

Puentes, Graciana; Waldherr, Gerald; Neumann, Philipp; Balasubramanian, Gopalakrishnan; Wrachtrup, Jörg

2014-01-01

211

Efficient route to high-bandwidth nanoscale magnetometry using single spins in diamond  

PubMed Central

Nitrogen-vacancy (NV) center in diamond is a promising quantum metrology tool finding applications across disciplines. The spin sensor measures magnetic fields, electric fields and temperature with nano-scale precision and is fully operable under ambient conditions. Moreover, it achieves precision scaling inversely with total measurement time ?B ? 1/T (Heisenberg scaling) rather than as the inverse of the square root of T, with the Shot-Noise limit. This scaling can be achieved by means of phase estimation algorithms (PEAs), in combination with single-shot read-out. Despite their accuracy, the range of applicability of PEAs is limited to sensing single frequencies with negligible temporal fluctuations. Nuclear Magnetic Resonance (NMR) signals from molecules often contain multifrequency components and sensing them using PEA is ruled out. Here we propose an alternative method for precision magnetometry in frequency multiplexed signals via compressive sensing (CS) techniques focusing on nanoscale NMR. We show that CS can provide for precision scaling approximately as ?B ? 1/T, as well as for a 5-fold increase in sensitivity over dynamic-range gain, in addition to reducing the total number of resources required. We illustrate our method by taking model solid-state spectra of Glycine acquired under Magic Angle Spinning conditions. PMID:24728454

Puentes, Graciana; Waldherr, Gerald; Neumann, Philipp; Balasubramanian, Gopalakrishnan; Wrachtrup, Jörg

2014-01-01

212

Nuclear Spin Orientation Dependence of Magnetoconductance: A New Method for Measuring the Spin of Charged Excitations in the QHE  

SciTech Connect

A new method for measuring the spin of the electrically charged ground state excitations m the Q$j~j quantum Hall effect ia proposed and demonstmted for the tirst time in GaAs/AIGaAs nndtiquantum wells. The method is &sed on the nuclear spin orientation dependence of" the 2D dc conductivity y in the quantum Hall regime due to the nuclear hyperfine interaction. As a demonstration of this method the spin of the electrically charged excitations of the ground state is determined at filling factor v = 1.

Bowers, C.R.; Reno, J.L.; Simmons, J.A.; Vitkalov, S.A.

1998-12-01

213

Free-induction decay and envelope modulations in a narrowed nuclear spin bath  

E-print Network

We evaluate free-induction decay for the transverse components of a localized electron spin coupled to a bath of nuclear spins via the Fermi contact hyperfine interaction. Our perturbative treatment is valid for special (narrowed) bath initial conditions and when the Zeeman energy of the electron $b$ exceeds the total hyperfine coupling constant $A$: $b>A$. Using one unified and systematic method, we recover previous results reported at short and long times using different techniques. We find a new and unexpected modulation of the free-induction-decay envelope, which is present even for a purely isotropic hyperfine interaction without spin echoes and for a single nuclear species. We give sub-leading corrections to the decoherence rate, and show that, in general, the decoherence rate has a non-monotonic dependence on electron Zeeman splitting, leading to a pronounced maximum. These results illustrate the limitations of methods that make use of leading-order effective Hamiltonians and re-exponentiation of short-time expansions for a strongly-interacting system with non-Markovian (history-dependent) dynamics.

W. A. Coish; Jan Fischer; Daniel Loss

2009-11-21

214

Two-Dimensional Nanoscale Imaging of Gadolinium Spins via Scanning Probe Relaxometry with a Single Spin in Diamond  

NASA Astrophysics Data System (ADS)

Spin labeling of molecules with paramagnetic ions is an important approach for determining molecular structure; however, current ensemble techniques lack the sensitivity to detect few isolated spins. In this paper, we demonstrate two-dimensional nanoscale imaging of paramagnetic gadolinium compounds using scanning relaxometry of a single nitrogen-vacancy (NV) center in diamond. Gadopentetate dimeglumine attached to an atomic-force microscope tip is controllably interacted with and detected by the NV center by virtue of the fact that the NV exhibits fast relaxation in the fluctuating magnetic field generated by electron spin flips in the gadolinium. Using this technique, we demonstrate a reduction in the T1 relaxation time of the NV center by over 2 orders of magnitude, probed with a spatial resolution of 20 nm. Our result exhibits the viability of the technique for imaging individual spins attached to complex nanostructures or biomolecules, along with studying the magnetic dynamics of isolated spins.

Pelliccione, M.; Myers, B. A.; Pascal, L. M. A.; Das, A.; Bleszynski Jayich, A. C.

2014-11-01

215

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

PubMed

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. PMID:25437256

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

216

Coherent control of single spins in silicon carbide at room temperature  

NASA Astrophysics Data System (ADS)

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.

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

217

Experimental demonstration of stimulated polarization wave in a chain of nuclear spins  

E-print Network

A stimulated wave of polarization, which implements a simple mechanism of quantum amplification, is experimentally demonstrated in a chain of four J-coupled nuclear spins, irradiated by a weak radio-frequency transverse field. The "quantum domino" dynamics, a wave of flipped spins triggered by a flip of the first spin, has been observed in fully $^{13}$C-labeled sodium butyrate.

Jae-Seung Lee; Travis Adams; A. K. Khitrin

2007-01-10

218

Nuclear Polarization and Impurity-State Spin Relaxation Processes in Silicon  

Microsoft Academic Search

Two proposals are made for producing nuclear polarization by a transient analog of the Overhauser effect in the impurity-state electron spin resonance in silicon. The success of the proposal polarization schemes requires that the electron spin relaxation process in which the impurity nucleus and the electron simultaneously flip their spins be faster than those relaxation processes in which an electron

David Pines; John Bardeen; Charles P. Slichter

1957-01-01

219

Two-qubit gate of combined single-spin rotation and interdot spin exchange in a double quantum dot.  

PubMed

A crucial requirement for quantum-information processing is the realization of multiple-qubit quantum gates. Here, we demonstrate an electron spin-based all-electrical two-qubit gate consisting of single-spin rotations and interdot spin exchange in a double quantum dot. A partially entangled output state is obtained by the application of the two-qubit gate to an initial, uncorrelated state. We find that the degree of entanglement is controllable by the exchange operation time. The approach represents a key step towards the realization of universal multiple-qubit gates. PMID:22107226

Brunner, R; Shin, Y-S; Obata, T; Pioro-Ladrière, M; Kubo, T; Yoshida, K; Taniyama, T; Tokura, Y; Tarucha, S

2011-09-30

220

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

221

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

PubMed Central

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

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

2014-01-01

222

Spin-path entanglement in single-neutron interferometer experiments  

SciTech Connect

There are two powerful arguments against the possibility of extending quantum mechanics (QM) into a more fundamental theory yielding a deterministic description of nature. One is the experimental violation of Bell inequalities, which discards local hidden-variable theories as a possible extension to QM. The other is the Kochen-Specker (KS) theorem, which stresses the incompatibility of QM with a larger class of hidden-variable theories, known as noncontextual hidden-variable theories. We performed experiments with neutron interferometer, which exploits spin-path entanglements in single neutrons. A Bell-like state is generated to demonstrate a violation of the Bell-like inequality and phenomena in accordance with KS theorem: both experiments study quantum contextuality and show clear evidence of the incompatibility of noncontextual hidden variable theories with QM. The value S = 2.202{+-}0.007 Neither-Less-Than-Nor-Equal-To 2 is obtained in the new measurement of the Bell-like inequality, which shows a larger violation than the previous measurement. For the study of KS theorem, the obtained violation 2.291{+-}0.008 Neither-Less-Than-Nor-Equal-To 1 clearly shows that quantum mechanical predictions cannot be reproduced by noncontextual hidden variable theories.

Hasegawa, Yuji; Erdoesi, Daniel [Atominstitut, Vienna University of Technology, Stadionallee 2, A-1020 Wien (Austria)

2011-09-23

223

Nuclear spin structure in dark matter search: The finite momentum transfer limit  

E-print Network

Spin-dependent elastic scattering of weakly interacting massive dark matter particles (WIMP) off nuclei is reviewed. All available, within different nuclear models, structure functions S(q) for finite momentum transfer (q>0) are presented. These functions describe the recoil energy dependence of the differential event rate due to the spin-dependent WIMP-nucleon interactions. This paper, together with the previous paper ``Nuclear spin structure in dark matter search: The zero momentum transfer limit'', completes our review of the nuclear spin structure calculations involved in the problem of direct dark matter search.

V. A. Bednyakov; F. Simkovic

2006-08-09

224

Nuclear spin structure in dark matter search: The finite momentum transfer limit  

NASA Astrophysics Data System (ADS)

Spin-dependent elastic scattering of weakly interacting massive dark matter particles (WIMP) off nuclei is reviewed. All available, within different nuclear models, structure functions S(q) for finite momentum transfer (q > 0) are presented. These functions describe the recoil energy dependence of the differential event rate due to the spin-dependent WIMP-nucleon interactions. This paper, together with the previous paper “Nuclear Spin Structure in Dark Matter Search: The Zero Momentum Transfer Limit,” completes our review of the nuclear spin structure calculations involved in the problem of direct dark matter search.

Bednyakov, V. A.; Šimkovic, F.

2006-12-01

225

Observation of spin-orbit splitting in lambda single-particle states.  

PubMed

The spin-orbit splitting of Lambda single-particle states in (13)(Lambda)C was measured. The 13C(K-,pi(-))(13)(Lambda)C reaction was used to excite both the 1/2(-) and 3/2(-) states simultaneously, which have predominantly 12C(0(+)) x p(Lambda) configuration. gamma rays from the states to the ground state were measured in coincidence with the pi(-)'s, by which ls splitting was found to be 152+/-54(stat)+/-36(syst) keV. The value is 20-30 times smaller than exhibited by the ls splitting in the nuclear shell model. This value gives us new insight into the YN interaction. PMID:11328148

Ajimura, S; Hayakawa, H; Kishimoto, T; Kohri, H; Matsuoka, K; Minami, S; Mori, T; Morikubo, K; Saji, E; Sakaguchi, A; Shimizu, Y; Sumihama, M; Chrien, R E; May, M; Pile, P; Rusek, A; Sutter, R; Eugenio, P; Franklin, G; Khaustov, P; Paschke, K; Quinn, B P; Schumacher, R A; Franz, J; Fukuda, T; Noumi, H; Outa, H; Gan, L; Tang, L; Yuan, L; Tamura, H; Nakano, J; Tamagawa, T; Tanida, K; Sawafta, R

2001-05-01

226

Nuclear spin selection rules in chemical reactions by angular momentum algebra  

E-print Network

Nuclear spin selection rules in chemical reactions by angular momentum algebra Takeshi Oka by Quack using molecular symmetry group are derived by using angu- lar momentum algebra. Instead: Selection rules; Nuclear spin modifications; Angular momentum algebra; Ion-neutral reactions; Molecular ions

Oka, Takeshi

227

Nuclear spin-lattice relaxation in the sodium anion, Na -  

NASA Astrophysics Data System (ADS)

We report direct measurements of nuclear spin-lattice relaxation times (T1n) for the sodium anion, Na-, in solutions containing both sodium and a heavier alkali metal in 1,4,7,10-tetraoxacyclododecane (12-crown-4, 12C4). Nuclear spin-lattice relaxation in Na- is found to be essentially independent of the alkali counterion and to depend only weakly upon the concentration of sodide ion in solution. The temperature dependence of T1n for Na- was used to determine an activation energy for the processes responsible for spin relaxation. The results are consistent with a dominant, but very inefficient, quadrupolar relaxation mechanism which involves the modulation of the electric field gradient at Na- via the reorientation and/or translational motion of surrounding 12C4 molecules in the liquid. Furthermore, we find that solvation of Na- in 12C4 as well described by a model in which there is neither preferential orientation of 12C4 molecules nor a clearly identifiable first solvation shell around the sodide ion. Consistent with this description, the activation energies for the processes responsible for spin-lattice relaxation in Na- are close to those observed for the processes causing 1H and 13C relaxation in the neat liquid crown. We outline two methods, which take into account electron-electron correlation effects, for determining the Sternheimer antishielding factor ?2 for the sodium anion. The most realistic estimate for ?2 (-14.98) is used to calculate the NMR linewidth for Na- when it is associated with an uncomplexed (unsolvated) sodium cation and also in the contact and solvent-separated Na+-Na- ion pairs. A rms value of 0.03 MHz for the quadrupole coupling constant (e2qQ/?) of Na- in 12C4 solutions is deduced. We conclude that Na- in these solutions suffers only minor perturbations on its gas-phase electronic structure; neither does it exist as part of a contact or solvent-separated ion pair. It appears that the sodide ion represents the closest realization of a gas-like ionic moiety in solution.

Holton, Dolores M.; Ellaboudy, Ahmed; Pyper, Nicholas C.; Edwards, Peter P.

1986-02-01

228

Nuclear spin optical rotation and Faraday effect in gaseous and liquid water.  

PubMed

Nuclear spin optical rotation (NSOR) of linearly polarized light, due to the nuclear spins through the Faraday effect, provides a novel probe of molecular structure and could pave the way to optical detection of nuclear magnetization. We determine computationally the effects of the liquid medium on NSOR and the Verdet constant of Faraday rotation (arising from an external magnetic field) in water, using the recently developed theory applied on a first-principles molecular dynamics trajectory. The gas-to-liquid shifts of the relevant antisymmetric polarizability and, hence, NSOR magnitude are found to be -14% and -29% for (1)H and (17)O nuclei, respectively. On the other hand, medium effects both enhance the local electric field in water and, via bulk magnetization, the local magnetic field. Together these two effects partially cancel the solvation influence on the single-molecular property. We find a good agreement for the hydrogen NSOR with a recent pioneering experiment on H(2)O(l). PMID:22583295

Pennanen, Teemu S; Ikäläinen, Suvi; Lantto, Perttu; Vaara, Juha

2012-05-14

229

High-fidelity gate operations with the coupled nuclear and electron spins of a nitrogen-vacancy center in diamond  

NASA Astrophysics Data System (ADS)

In this article we investigate the dynamics of a single negatively charged nitrogen-vacancy center (NV-) coupled to the spin of the nucleus of a 15-nitrogen atom and show that high-speed, high-fidelity gate operations are possible without the need for complicated composite pulse sequences. These operations include both the electron and nuclear spin rotations, as well as an entangling gate between them. These are the primitive gates one will need within a quantum node of a distributed communication network.

Everitt, Mark S.; Devitt, Simon; Munro, W. J.; Nemoto, Kae

2014-05-01

230

Electron-nuclear spin control in charged semiconductor quantum dots by electrical currents through micro-coils  

NASA Astrophysics Data System (ADS)

We have fabricated micrometer-sized single-turn coils on top of charged CdSe/ZnSe quantum dot heterostructures by lithographical techniques. Current injection creates magnetic fields in the some 10 mT range, strong enough to modulate the hyperfine interaction. The very low coil inductance allows for generation of fast field transients. We demonstrate local control of the resident electron spin as well as read-out of the nuclear spin state on the 10 ns time scale by electrical current pulses.

Kim, Jungtaek; Puls, J.; Chen, Y. S.; Bacher, G.; Henneberger, F.

2010-04-01

231

A 3D-Printed High Power Nuclear Spin Polarizer  

PubMed Central

Three-dimensional printing with high-temperature plastic is used to enable spin exchange optical pumping (SEOP) and hyperpolarization of xenon-129 gas. The use of 3D printed structures increases the simplicity of integration of the following key components with a variable temperature SEOP probe: (i) in situ NMR circuit operating at 84 kHz (Larmor frequencies of 129Xe and 1H nuclear spins), (ii) <0.3 nm narrowed 200 W laser source, (iii) in situ high-resolution near-IR spectroscopy, (iv) thermoelectric temperature control, (v) retroreflection optics, and (vi) optomechanical alignment system. The rapid prototyping endowed by 3D printing dramatically reduces production time and expenses while allowing reproducibility and integration of “off-the-shelf” components and enables the concept of printing on demand. The utility of this SEOP setup is demonstrated here to obtain near-unity 129Xe polarization values in a 0.5 L optical pumping cell, including ~74 ± 7% at 1000 Torr xenon partial pressure, a record value at such high Xe density. Values for the 129Xe polarization exponential build-up rate [(3.63 ± 0.15) × 10?2 min?1] and in-cell 129Xe spin?lattice relaxation time (T1 = 2.19 ± 0.06 h) for 1000 Torr Xe were in excellent agreement with the ratio of the gas-phase polarizations for 129Xe and Rb (PRb ~ 96%). Hyperpolarization-enhanced 129Xe gas imaging was demonstrated with a spherical phantom following automated gas transfer from the polarizer. Taken together, these results support the development of a wide range of chemical, biochemical, material science, and biomedical applications. PMID:24400919

Nikolaou, Panayiotis; Coffey, Aaron M.; Walkup, Laura L.; Gust, Brogan M.; LaPierre, Cristen D.; Koehnemann, Edward; Barlow, Michael J.; Rosen, Matthew S.; Goodson, Boyd M.; Chekmenev, Eduard Y.

2015-01-01

232

A coherent triggered search for single spin compact binary coalescences in gravitational wave data  

E-print Network

In this paper we present a method for conducting a coherent search for single spin compact binary coalescences in gravitational wave data and compare this search to the existing coincidence method for single spin searches. We propose a method to characterize the regions of the parameter space where the single spin search, both coincident and coherent, will increase detection efficiency over the existing non-precessing search. We also show example results of the coherent search on a stretch of data from LIGO's fourth science run but note that a set of signal based vetoes will be needed before this search can be run to try to make detections.

Ian Harry; Stephen Fairhurst

2011-01-07

233

Frequency selective detection of nuclear quadrupole resonance (NQR) spin echoes  

NASA Astrophysics Data System (ADS)

Nuclear Quadrupole Resonance (NQR) is a radio frequency (RF) technique that can be used to detect the presence of quadrupolar nuclei, such as the 14N nucleus prevalent in many explosives and narcotics. The technique has been hampered by low signal-to-noise ratios and is further aggravated by the presence of RF interference (RFI). To ensure accurate detection, proposed detectors should exploit the rich form of the NQR signal. Furthermore, the detectors should also be robust to any remaining residual interference, left after suitable RFI mitigation has been employed. In this paper, we propose a new NQR data model, particularly for the realistic case where multiple pulse sequences are used to generate trains of spin echoes. Furthermore, we refine two recently proposed approximative maximum likelihood (AML) detectors, enabling the algorithm to optimally exploit the data model of the entire echo train and also incorporate knowledge of the temperature dependent spin-echo decay time. The AML-based detectors ensure accurate detection and robustness against residual RFI, even when the temperature of the sample is not precisely known, by exploiting the dependencies of the NQR resonant lines on temperature. Further robustness against residual interference is gained as the proposed detector is frequency selective; exploiting only those regions of the spectrum where the NQR signal is expected. Extensive numerical evaluations based on both simulated and measured NQR data indicate that the proposed Frequency selective Echo Train AML (FETAML) detector offers a significant improvement as compared to other existing detectors.

Somasundaram, Samuel D.; Jakobsson, Andreas; Smith, John A. S.; Althoefer, Kaspar A.

2006-05-01

234

Spin-related thermoelectric conversion in lateral spin-valve devices with single-crystalline Co2FeSi electrodes  

NASA Astrophysics Data System (ADS)

We demonstrate the conversion between a heat current and a spin current in Cu-based lateral spin valves (LSVs) with single-crystalline Co2FeSi (CFS) electrodes. We can observe the thermally induced spin injection from CFS into Cu resulting from the spin-dependent Seebeck effect, and the heat current generated by the spin-dependent Peltier effect can be detected even in the LSV structures. This study is an important step toward understanding heat-spin conversion in single-crystalline materials with various electronic band structures.

Yamasaki, Kento; Oki, Soichiro; Yamada, Shinya; Kanashima, Takeshi; Hamaya, Kohei

2015-04-01

235

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

NASA Astrophysics Data System (ADS)

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.

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

2000-08-01

236

Spin dynamics in the optical cycle of single nitrogen-vacancy centres in diamond  

E-print Network

We investigate spin-dependent decay and intersystem crossing in the optical cycle of single negatively-charged nitrogen-vacancy (NV) centres in diamond. We use spin control and pulsed optical excitation to extract both the spin-resolved lifetimes of the excited states and the degree of optically-induced spin polarization. By optically exciting the centre with a series of picosecond pulses, we determine the spin-flip probabilities per optical cycle, as well as the spin-dependent probability for intersystem crossing. This information, together with the indepedently measured decay rate of singlet population provides a full description of spin dynamics in the optical cycle of NV centres. The temperature dependence of the singlet population decay rate provides information on the number of singlet states involved in the optical cycle.

Lucio Robledo; Hannes Bernien; Toeno van der Sar; Ronald Hanson

2010-10-06

237

Spin dynamics in the optical cycle of single nitrogen-vacancy centres in diamond  

E-print Network

We investigate spin-dependent decay and intersystem crossing in the optical cycle of single negatively-charged nitrogen-vacancy (NV) centres in diamond. We use spin control and pulsed optical excitation to extract both the spin-resolved lifetimes of the excited states and the degree of optically-induced spin polarization. By optically exciting the centre with a series of picosecond pulses, we determine the spin-flip probabilities per optical cycle, as well as the spin-dependent probability for intersystem crossing. This information, together with the indepedently measured decay rate of singlet population provides a full description of spin dynamics in the optical cycle of NV centres. The temperature dependence of the singlet population decay rate provides information on the number of singlet states involved in the optical cycle.

Robledo, Lucio; van der Sar, Toeno; Hanson, Ronald

2010-01-01

238

All optical control of a single electron spin in diamond  

E-print Network

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.

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

2014-09-22

239

Separating subspectra from cross-polarization magic-angle spinning nuclear magnetic resonance spectra by proton spin relaxation editing  

Microsoft Academic Search

Differences in proton spin relaxation time constants can be exploited to edit cross-polarization magic-angle spinning nuclear magnetic resonance (CP-MAS NMR) spectra of heterogeneous mixtures of different types of organic matter. This paper describes an extension of the editing procedure from two-component to three-component mixtures. Clean separation of 13C NMR subspectra was achieved for three synthetic polymers mixed as powders. Applying

Roger H. Newman; Leo M. Condron

1995-01-01

240

Spin interference in the spin density matrix of a compound nucleus in reactions of nuclear fission by cold polarized neutrons  

Microsoft Academic Search

Spin density matrices of neutron resonance states of a compound nucleus formed in the reaction of capture of a polarized neutron\\u000a by a non-oriented target nucleus for different directions of neutron polarization vector are constructed within the quantum\\u000a fission theory. The obtained spin matrices are used to calculate T-odd asymmetries in differential cross sections of ternary\\u000a nuclear fission with the

S. G. Kadmensky; L. V. Titova; V. E. Bunakov

2011-01-01

241

Phase-Sensitive Probes of Nuclear Polarization in Spin-Blockaded Quantum Dots  

NASA Astrophysics Data System (ADS)

Semiconducting quantum dots provide a platform for investigating the quantum many-body dynamics of coupled electron and nuclear spins. The phenomenon of spin blockade, wherein the Pauli exclusion principle requires electrons to flip their spins in order to pass through the system [1], is an invaluable tool in this pursuit. We describe a new regime of coupled electron and nuclear spin dynamics in spin-blockaded quantum dots where the hyperfine coupling to nuclear spins competes with a purely electronic spin-flip mechanism, such as the spin-orbit interaction or coupling to an inhomogeneous Zeeman field [M. S. Rudner et al., arXiv:0909.0060]. We show that the long-lived coherence of the nuclear spin bath plays a crucial role and leads to a range of new surprising phenomena. In particular, a purely electrical detection of coherent nuclear precession can be realized. Recent results of Foletti et al. [arXiv:0801.3613] suggest that this interesting new regime is now within experimental reach. [1] K. Ono et al. Science 297, 1313 (2002).

Rudner, Mark; Neder, Izhar; Levitov, Leonid; Halperin, Bertrand

2010-03-01

242

Spin-orbit decomposition of ab initio nuclear wave functions  

NASA Astrophysics Data System (ADS)

Although the modern shell-model picture of atomic nuclei is built from single-particle orbits with good total angular momentum j , leading to j -j coupling, decades ago phenomenological models suggested that a simpler picture for 0 p -shell nuclides can be realized via coupling of the total spin S and total orbital angular momentum L . I revisit this idea with large-basis, no-core shell-model calculations using modern ab initio two-body interactions and dissect the resulting wave functions into their component L - and S -components. Remarkably, there is broad agreement with calculations using the phenomenological Cohen-Kurath forces, despite a gap of nearly 50 years and six orders of magnitude in basis dimensions. I suggest that L -S decomposition may be a useful tool for analyzing ab initio wave functions of light nuclei, for example, in the case of rotational bands.

Johnson, Calvin W.

2015-03-01

243

Spin-resolved measurements of single molecular magnets on graphene  

NASA Astrophysics Data System (ADS)

The use of magnetic molecules opens a gateway to a flexible design of novel spintronic devices to store, manipulate, and read spin information at the nanoscale. Crucial is the precise knowledge of molecular properties at the interface towards an electrode. Progress in this field relies on resolving and understanding the physics at the relevant interfaces. In particular the role of individual molecular constituents and the impact of the atomic environment on molecular properties determine device relevant parameters, such as conductance and spin polarization. Recently, the incorporation of a graphene sheet to electronically decouple molecules from a ferromagnetic surface has been addressed by surface averaging high-resolution electron energy loss spectroscopy. Here, we applied spin-polarized scanning tunneling microscopy to resolve the physics of the molecule-graphene-ferromagnet interface. The analysis focuses on different phthalocyanine molecules adsorbed on cobalt-intercalated graphene on Ir(111). The phthalocyanine constitutes of an organic macrocyclic ligand and can be functionalized with various metal ions in order to modify, e.g. the molecular spin state. We will discuss the spin-dependent transport from magnetic surfaces through such molecules. In particular, the spin polarization of molecular frontier orbitals is resolved with sub-molecular spatial resolution and the variations in the lifetimes of different orbitals are discussed.

Brede, Jens; Decker, Regis; Schwoebel, Joerg; Bazarnik, Maciej; Wiesendanger, Roland

2013-03-01

244

Spin valleytronics in silicene: Quantum spin Hall-quantum anomalous Hall insulators and single-valley semimetals  

NASA Astrophysics Data System (ADS)

Valley-based electronics, known as valleytronics, is one of the keys to breaking through to a new stage of electronics. The valley degree of freedom is ubiquitous in the honeycomb lattice system. The honeycomb lattice structure of silicon, called silicene, is a fascinating playground of valleytronics. We investigate topological phases of silicene by introducing different exchange fields on the A and B sites. There emerges a rich variety of topologically protected states, each of which has a characteristic spin-valley structure. The single Dirac-cone semimetal is such a state where one gap is closed while the other three gaps are open, evading the Nielsen-Ninomiya fermion-doubling problem. We have newly discovered a hybrid topological insulator named the quantum spin-quantum anomalous Hall insulator, where the quantum anomalous Hall effect occurs at one valley and the quantum spin Hall effect occurs at the other valley. Along its phase boundary, single-valley semimetals emerge, where only one of the two valleys is gapless with degenerated spins. These semimetals are also topologically protected because they appear in the interface of different topological insulators. Such a spin-valley-dependent physics will be observed by optical absorption or edge modes.

Ezawa, Motohiko

2013-04-01

245

Transverse Single Spin and Azimuthal Asymmetries in Hadronic Collisions at STAR  

NASA Astrophysics Data System (ADS)

Hadronic collisions with transversely polarized protons are an important part of the quest to understand the transverse spin structure of the proton. Experiments at RHIC collected large datasets at center of mass energies of 200 GeV and 500 GeV, accessing a kinematic regime where factorization is expected to hold. The STAR detector at RHIC, due to its azimuthal symmetry, particle identification capabilities and large acceptance compared with other experiments with polarized protons, is in a unique position to study transverse spin phenomena in p + p?. This contribution will highlight measurements of transversity using di-hadron correlations, transverse single spin asymmetries in jets, measurements sensitive to the origins of the large single spin asymmetries measured in the forward direction, transverse spin asymmetries in W production, which are sensitive to modified universality effects of Sivers function as well as short and long-term upgrades at STAR.

Vossen, Anselm

2015-01-01

246

Rényi information flow in the Ising model with single-spin dynamics  

NASA Astrophysics Data System (ADS)

The n -index Rényi mutual information and transfer entropies for the two-dimensional kinetic Ising model with arbitrary single-spin dynamics in the thermodynamic limit are derived as functions of ensemble averages of observables and spin-flip probabilities. Cluster Monte Carlo algorithms with different dynamics from the single-spin dynamics are thus applicable to estimate the transfer entropies. By means of Monte Carlo simulations with the Wolff algorithm, we calculate the information flows in the Ising model with the Metropolis dynamics and the Glauber dynamics, respectively. We find that not only the global Rényi transfer entropy, but also the pairwise Rényi transfer entropy, peaks in the disorder phase.

Deng, Zehui; Wu, Jinshan; Guo, Wenan

2014-12-01

247

Boundary between the thermal and statistical polarization regimes in a nuclear spin ensemble  

SciTech Connect

As the number of spins in an ensemble is reduced, the statistical fluctuations in its polarization eventually exceed the mean thermal polarization. This transition has now been surpassed in a number of recent nuclear magnetic resonance experiments, which achieve nanometer-scale detection volumes. Here, we measure nanometer-scale ensembles of nuclear spins in a KPF{sub 6} sample using magnetic resonance force microscopy. In particular, we investigate the transition between regimes dominated by thermal and statistical nuclear polarization. The ratio between the two types of polarization provides a measure of the number of spins in the detected ensemble.

Herzog, B. E.; Cadeddu, D.; Xue, F.; Peddibhotla, P.; Poggio, M., E-mail: martino.poggio@unibas.ch [Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland)

2014-07-28

248

Single-level resonance parameters fit nuclear cross-sections  

NASA Technical Reports Server (NTRS)

Least squares analyses of experimental differential cross-section data for the U-235 nucleus have yielded single level Breit-Wigner resonance parameters that fit, simultaneously, three nuclear cross sections of capture, fission, and total.

Drawbaugh, D. W.; Gibson, G.; Miller, M.; Page, S. L.

1970-01-01

249

Sensing thermal motion of a mechanical resonator using a single spin qubit in diamond  

NASA Astrophysics Data System (ADS)

We present experimental results demonstrating the detection of the motion of a magnetized mechanical cantilever using a single spin qubit associated with a nitrogen-vacancy (NV) defect center in diamond. This setup is predicted to enable strong, coherent coupling between the NV electronic spin and the motion of the cantilever, allowing for the mechanical analog of cavity quantum electrodynamics [1]. To this end, we use the NV spin to detect both driven and thermal motion of a magnetic force microscope cantilever at room temperature, reading out the spin state optically using the spin-selective fluorescence of the NV. This method utilizes the high sensitivity of the NV spin precession to Zeeman shifts caused by the a.c. magnetic field induced by the motion of the cantilever. Finally, we discuss potential applications of our approach to the realization of quantum spin transducers using arrays of coupled spin-cantilever pairs [2]. 1. Rabl, P. et al. Strong magnetic coupling between an electronic spin qubit and a mechanical resonator. Physical Review B 79, 41302 (2009). 2. Rabl, P. et al. A quantum spin transducer based on nanoelectromechanical resonator arrays. Nature Physics 6, 602--608 (2010).

Kolkowitz, Shimon; Bleszynski Jayich, Ania; Rabl, Peter; Bennet, Steven; Unterreithmeier, Quirin; Harris, Jack; Lukin, Mikhail

2011-06-01

250

Single antidot as a passive way to create caustic spin-wave beams in yttrium iron garnet films  

E-print Network

Single antidot as a passive way to create caustic spin-wave beams in yttrium iron garnet films R://apl.aip.org/about/rights_and_permissions #12;Single antidot as a passive way to create caustic spin-wave beams in yttrium iron garnet films R in yttrium iron garnet film. Diffraction of surface magnetostatic spin waves from such antidot

Demokritov, S.O.

251

Conditional control of donor nuclear spins in silicon using Stark shifts  

E-print Network

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.

Gary Wolfowicz; Matias Urdampilleta; Mike L. W. Thewalt; Helge Riemann; Nikolai V. Abrosimov; Peter Becker; Hans-Joachim Pohl; John J. L. Morton

2014-05-28

252

Accessing long-lived nuclear singlet states between chemically equivalent spins without breaking symmetry  

PubMed Central

Long-lived nuclear spin states could greatly enhance the applicability of hyperpolarized nuclear magnetic resonance. Using singlet states between inequivalent spin pairs has been shown to extend the signal lifetime by more than an order of magnitude compared to the spin lattice relaxation time (T1), but they have to be prevented from evolving into other states. In the most interesting case the singlet is between chemically equivalent spins, as it can then be inherently an eigenstate. However this presents major challenges in the conversion from bulk magnetization to singlet. In the only case demonstrated so far, a reversible chemical reaction to break symmetry was required. Here we present a pulse sequence technique that interconverts between singlet spin order and bulk magnetization without breaking the symmetry of the spin system. This technique is independent of field strength and is applicable to a broad range of molecules. PMID:23505397

Feng, Yesu; Davis, Ryan M.; Warren, Warren S.

2013-01-01

253

Initial-state interactions and single-spin asymmetries in Drell-Yan processes  

NASA Astrophysics Data System (ADS)

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 H1H2??? +? -X. The QCD initial-state interactions produce a T-odd spin-correlation S?H 2· P?H 1× 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 Q2 at fixed xF. The single-spin asymmetry which arises from the initial-state interactions is not related to the target or projectile transversity distribution ?qH( x, Q). The origin of the single-spin asymmetry in ?p??? +? -X is a phase difference between two amplitudes coupling the proton target with J zp=± {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: ?Lz=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 ?p??? +? -X is similar to the single-spin asymmetries in deep inelastic semi-inclusive leptoproduction ? p???' ?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 highlight the importance of initial- and final-state interactions for QCD observables.

Brodsky, Stanley J.; Hwang, Dae Sung; Schmidt, Ivan

2002-10-01

254

Sensitivity of nuclear-quadrupole double-resonance detection of half-integer spin nuclei.  

PubMed

The sensitivity of the Slusher and Hahn's nuclear quadrupole double resonance technique is calculated in general for an arbitrary nuclear spin S of the quadrupole nuclei and for an arbitrary asymmetry parameter eta of the electric field gradient tensor. The nuclear spin S=5/2 ((17)O, (25)Mg, ...) is treated in details. The influence of the cross-relaxation rate between the quadrupole nuclei and the abundant spin system on the sensitivity of double resonance is discussed. The results of the theoretical analysis are applied in the analysis of the (1)H-(17)O nuclear quadrupole double resonance spectra in p-toluenesulfonamide and 2-nitrobenzoic acid. The 17O nuclear quadrupole resonance frequencies from a sulfonamide group are determined for the first time. The proton-oxygen cross-relaxation rates and the proton local frequency in zero external magnetic field are experimentally determined from the nuclear quadrupole double resonance spectra. PMID:18644741

Seliger, J; Zagar, V

2008-10-01

255

Spin-pseudospin intertwined excitation at the ? = 1 bilayer quantum Hall state investigated by nuclear-spin relaxation  

SciTech Connect

We investigate the electron spin degree of freedom at the imbalanced density bilayer ? = 1 quantum Hall states using the resistively detected nuclear-spin-lattice relaxation rate 1/T{sub 1}. Our measurements reveal a continuous change in 1/T{sub 1} for ? = 1 to 0, suggesting that the balanced density ? = 1 state also exhibits electron-spin fluctuations. Moreover, the value of 1/T{sub 1} in the back layer (the layer from which electrons are transferred to the front layer) increases at intermediate density imbalance states. This indicates that the low-energy electron-spin mode, similar to a mode observed in Skyrmion crystals, might extend across the two layers.

Tsuda, S.; Nguyen, M. H. [Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Terasawa, D.; Fukuda, A. [Department of Physics, Hyogo College of Medicine, Nishinomiya 663-8501 (Japan); Zheng, Y. D.; Arai, T.; Sawada, A. [Research Center for Low Temperatures and Materials Sciences, Kyoto University, Kyoto 606-8501 (Japan); Ezawa, Z. F. [Advanced Meson Science Laboratory, Riken, Wako 980-8578 (Japan)

2013-12-04

256

A high-performance Fortran code to calculate spin- and parity-dependent nuclear level densities  

NASA Astrophysics Data System (ADS)

A high-performance Fortran code is developed to calculate the spin- and parity-dependent shell model nuclear level densities. The algorithm is based on the extension of methods of statistical spectroscopy and implies exact calculation of the first and second Hamiltonian moments for different configurations at fixed spin and parity. The proton-neutron formalism is used. We have applied the method for calculating the level densities for a set of nuclei in the sd-, pf-, and pf+g- model spaces. Examples of the calculations for 28Si (in the sd-model space) and 64Ge (in the pf+g-model space) are presented. To illustrate the power of the method we estimate the ground state energy of 64Ge in the larger model space pf+g, which is not accessible to direct shell model diagonalization due to the prohibitively large dimension, by comparing with the nuclear level densities at low excitation energy calculated in the smaller model space pf. Program summaryProgram title: MM Catalogue identifier: AENM_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENM_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 193181 No. of bytes in distributed program, including test data, etc.: 1298585 Distribution format: tar.gz Programming language: Fortran 90, MPI. Computer: Any architecture with a Fortran 90 compiler and MPI. Operating system: Linux. RAM: Proportional to the system size, in our examples, up to 75Mb Classification: 17.15. External routines: MPICH2 (http://www.mcs.anl.gov/research/projects/mpich2/) Nature of problem: Calculating of the spin- and parity-dependent nuclear level density. Solution method: The algorithm implies exact calculation of the first and second Hamiltonian moments for different configurations at fixed spin and parity. The code is parallelized using the Message Passing Interface and a master-slaves dynamical load-balancing approach. Restrictions: The program uses two-body interaction in a restricted single-level basis. For example, GXPF1A in the pf-valence space. Running time: Depends on the system size and the number of processors used (from 1 min to several hours).

Sen'kov, R. A.; Horoi, M.; Zelevinsky, V. G.

2013-01-01

257

Nuclear-Spin Gyroscope Based on an Atomic Co-Magnetometer  

NASA Technical Reports Server (NTRS)

An experimental nuclear-spin gyroscope is based on an alkali-metal/noblegas co-magnetometer, which automatically cancels the effects of magnetic fields. Whereas the performances of prior nuclear-spin gyroscopes are limited by sensitivity to magnetic fields, this gyroscope is insensitive to magnetic fields and to other external perturbations. In addition, relative to prior nuclear-spin gyroscopes, this one exhibits greater sensitivity to rotation. There is commercial interest in development of small, highly sensitive gyroscopes. The present experimental device could be a prototype for development of nuclear spin gyroscopes suitable for navigation. In comparison with fiber-optic gyroscopes, these gyroscopes would draw less power and would be smaller, lighter, more sensitive, and less costly.

Romalis, Michael; Komack, Tom; Ghost, Rajat

2008-01-01

258

Cryogenic sample exchange NMR probe for magic angle spinning dynamic nuclear polarization  

E-print Network

We describe a cryogenic sample exchange system that dramatically improves the efficiency of magic angle spinning (MAS) dynamic nuclear polarization (DNP) experiments by reducing the time required to change samples and by ...

Barnes, Alexander B.

259

Atomic-Scale Nuclear Spin Imaging Using Quantum-Assisted Sensors in Diamond  

E-print Network

Nuclear spin imaging at the atomic level is essential for the understanding of fundamental biological phenomena and for applications such as drug discovery. The advent of novel nanoscale sensors promises to achieve the ...

Bissbort, U.

260

Nuclear spin relaxation in a vinylidene fluoride and trifluoroethylene copolymer 70/30  

E-print Network

563 Nuclear spin relaxation in a vinylidene fluoride and trifluoroethylene copolymer 70/30 I phase paraélectrique (au-dessus du point de Curie). Abstract. 2014 The spin dynamics of hydrogen fluoride (PVF2) is known to possess a polar crystalline 3 phase were the chains are in the all

Boyer, Edmond

261

The determination of the in situ structure by nuclear spin contrast variation  

SciTech Connect

Polarized neutron scattering from polarized nuclear spins in hydrogenous substances opens a new way of contrast variation. The enhanced contrast due to proton spin polarization was used for the in situ structure determination of tRNA of the functional complex of the E.coli ribosome.

Stuhrmann, H.B. [GKSS Forschungszentrum, Geesthacht (Germany); Nierhaus, K.H. [Max-Planch-Institut fuer Molekulare Genetik, Berlin (Germany)

1994-12-31

262

Lattice dynamics in spin-crossover nanoparticles through nuclear inelastic scattering  

NASA Astrophysics Data System (ADS)

We used nuclear inelastic scattering (NIS) to investigate the lattice dynamics in [Fe(pyrazine)(Ni(CN)4)] spin crossover nanoparticles. The vibrational density of states of iron was extracted from the NIS data, which allowed to determine characteristic thermodynamical and lattice dynamical parameters as well as their spin-state dependence. The optical part of the NIS spectra compares well with the Raman scattering data reflecting the expansion/contraction of the coordination octahedron during the spin transition. From the acoustic part, we extracted the sound velocity in the low-spin (vLS=2073 ±31 m s-1) and high-spin (vHS=1942 ±23 m s-1) states of the particles. The spin-state dependence of this parameter is of primary interest to rationalize the spin-transition behavior in solids as well as its dynamics and finite size effects.

Félix, Gautier; Mikolasek, Mirko; Peng, Haonan; Nicolazzi, William; Molnár, Gábor; Chumakov, Aleksandr I.; Salmon, Lionel; Bousseksou, Azzedine

2015-01-01

263

A light-induced spin crossover actuated single-chain magnet  

NASA Astrophysics Data System (ADS)

Both spin-crossover complexes and molecular nanomagnets display bistable magnetic states, potentially behaving as elementary binary units for information storage. It is a challenge to introduce spin-crossover units into molecular nanomagnets to switch the bistable state of the nanomagnets through external stimuli-tuned spin crossover. Here we report an iron(II) spin-crossover unit and paramagnetic iron(III) ions that are incorporated into a well-isolated double-zigzag chain. The chain exhibits thermally induced reversible spin-crossover and light-induced excited spin-state trapping at the iron(II) sites. Single-chain magnet behaviour is actuated accompanying the synergy between light-induced excited spin-state trapping at the iron(II) sites and ferromagnetic interactions between the photoinduced high-spin iron(II) and low-spin iron(III) ions in the chain. The result provides a strategy to switch the bistable state of molecular nanomagnets using external stimuli such as light and heat, with the potential to erase and write information at a molecular level.

Liu, Tao; Zheng, Hui; Kang, Soonchul; Shiota, Yoshihito; Hayami, Shinya; Mito, Masaki; Sato, Osamu; Yoshizawa, Kazunari; Kanegawa, Shinji; Duan, Chunying

2013-11-01

264

Measurement of single transverse spin asymmetry AN in forward neutron production ?s=200GeV  

NASA Astrophysics Data System (ADS)

Relativistic Heavy Ion Collider (RHIC) completed its third run in May 2003. The run included a 5 week period in which it collided polarized proton at ?s=200GeV for the first time. Single transverse spin left-right asymmetries in neutron production were observed in the large rapidity region by the PHENIX collaboration using the Zero Degree Calorimeters (ZDC) and (embedded) segmented Shower Max Detectors (SMD). The results confirm the discovery of the left-right analyzing power in the p^arrowp arrow Nx process at RHIC [1] made last year. This year the asymmetries were used, first, for commissioning of the PHENIX spin rotators and then, during the physics run (measurement of double spin asymmetries A_LL) to monitor the proton spin direction. Longitudinal double spin asymmetry (A_LL) resulting from these data are expected to give the first glimpse of the role played by the gluons in determining the nucleon's spin. This talk will cover the status of the asymmetry analysis and comments on its origin, the use of these asymmetries in the commissioning of the spin rotators, and monitoring the spin direction of the proton during the physics data taking period. [1] Y. FUkao et al., Proceedings of SPIN 2002, to be published.

Deshpande, Abhay

2003-10-01

265

Teleportation of Electronic Many-Qubit States Encoded in the Electron Spin of Quantum Dots via Single Photons  

Microsoft Academic Search

We propose a teleportation scheme that relies only on single-photon measurements and Faraday rotation, for teleportation of many-qubit entangled states stored in the electron spins of a quantum dot system. The interaction between a photon and the two electron spins, via Faraday rotation in micro- cavities, establishes Greenberger-Horne-Zeilinger entanglement in the spin-photon-spin system. The appropriate single-qubit measurements, and the communication

Michael N. Leuenberger; Michael E. Flatte; D. D. Awschalom

2005-01-01

266

Teleportation of Electronic Many-Qubit States Encoded in the Electron Spin of Quantum Dots via Single Photons  

Microsoft Academic Search

We propose a teleportation scheme that relies only on single-photon measurements and Faraday rotation, for teleportation of many-qubit entangled states stored in the electron spins of a quantum dot system. The interaction between a photon and the two electron spins, via Faraday rotation in microcavities, establishes Greenberger-Horne-Zeilinger entanglement in the spin-photon-spin system. The appropriate single-qubit measurements, and the communication of

Michael N. Leuenberger; Michael E. Flatté; D. D. Awschalom

2005-01-01

267

Multipulse operation and optical detection of nuclear spin coherence in a GaAs/AlGaAs quantum well.  

PubMed

We demonstrate manipulation of nuclear spin coherence in a GaAs/AlGaAs quantum well by optically detected nuclear magnetic resonance (NMR). A phase shift of the Larmor precession of photoexcited electron spins is detected to read out the hyperfine-coupled nuclear spin polarization. Multipulse NMR sequences are generated to control the population and examine the phase coherence in quadrupolar-split spin-3/2 75As nuclei. The phase coherence among the multilevel nuclear spin states is addressed by application of pulse sequences that are used in quantum gate operations. PMID:19113379

Kondo, Y; Ono, M; Matsuzaka, S; Morita, K; Sanada, H; Ohno, Y; Ohno, H

2008-11-14

268

Nuclear Spin Gyroscope Based on an Atomic Comagnetometer T. W. Kornack, R. K. Ghosh, and M. V. Romalis  

E-print Network

Nuclear Spin Gyroscope Based on an Atomic Comagnetometer T. W. Kornack, R. K. Ghosh, and M. V; published 29 November 2005) We describe a nuclear spin gyroscope based on an alkali their gyroscopic precession. Spin precession due to magnetic fields as well as their gradients and transients can

Romalis, Mike

269

Spin splitting anisotropy in single diluted magnetic nanowire heterostructures.  

PubMed

We study the impact of the nanowire shape anisotropy on the spin splitting of excitonic photoluminescence. The experiments are performed on individual ZnMnTe/ZnMgTe core/shell nanowires as well as on ZnTe/ZnMgTe core/shell nanowires containing optically active magnetic CdMnTe insertions. When the magnetic field is oriented parallel to the nanowire axis, the spin splitting is several times larger than for the perpendicular field. We interpret this pronounced anisotropy as an effect of mixing of valence band states arising from the strain present in the core/shell geometry. This interpretation is further supported by theoretical calculations which allow to reproduce experimental results. PMID:25710186

Szymura, Ma?gorzata; Wojnar, Piotr; K?opotowski, ?ukasz; Suffczy?ski, Jan; Goryca, Mateusz; Smole?ski, Tomasz; Kossacki, Piotr; Zaleszczyk, Wojciech; Wojciechowski, Tomasz; Karczewski, Grzegorz; Wojtowicz, Tomasz; Kossut, Jacek

2015-03-11

270

Single spin asymmetries for identified hadrons at COMPASS  

NASA Astrophysics Data System (ADS)

COMPASS is a fixed target experiment at CERN SPS, dedicated to the study of the nucleon spin structure and hadron spectroscopy. The transverse spin structure of the nucleon is investigated by measuring semi-inclusive deep inelastic scattering (SIDIS) of a 160 GeV/c longitudinally polarized muon beam off transversely polarised targets. Particle Identification (PID) is performed with a Ring Imaging CHerenkov detector (RICH) that has been upgraded in 2005. COMPASS took data using transversely polarised 6LiD target from 2002 to 2004 and with a transversely polarised NH3 target in 2007. In this talk the Collins and Sivers asymmetries on polarised proton for charged pions and kaons will be shown for the first time and compared with the same results on polarised deuteron for COMPASS.

Pesaro, Giulia; Compass Collaboration

2011-05-01

271

Imaging single spin probes embedded in a conductive diamagnetic layer.  

SciTech Connect

The detection of spin noise by means of scanning tunneling microscopy (STM) has recently been substantially improved by the work presented by Komeda and Manassen (Komeda, T.; Manassen, Y. Appl. Phys. Lett. 2008, 92, 212506). The application of this technique to molecular paramagnets requires the positioning and anchoring of paramagnetic molecules at surfaces. It also requires the possibility of tunneling high current densities into the STM-molecule-substrate tunneling junction. In this letter, we exploit the self-assembly of 1,10-phenantroline on the Au(111) surface to form a diamagnetic matrix that hosts individual molecules and dimers of diphenyl-2-picryl-hydrazyl (DPPH). STM measurements are used to characterize the molecular layer. Electron spin resonance (ESR) measurements elucidate the role of thermal annealing in the preservation of the paramagnetic nature of the DPPH molecules.

Messina, P.; Fradin, F. (Materials Science Division)

2009-01-01

272

Universal dynamics of quantum spin decoherence in a nuclear spin bath Yi-Ya Tian, Pochung Chen, and Daw-Wei Wang  

E-print Network

Universal dynamics of quantum spin decoherence in a nuclear spin bath Yi-Ya Tian, Pochung Chen, and Daw-Wei Wang Physics Department, National Tsing-Hua University, Hsinchu, Taiwan 30013, Republic systematically investigate the universal spin decoherence dynamics of a localized electron in an arbitrary

Wang, Daw-Wei

273

Excited-state spectroscopy using single-spin manipulation in diamond  

E-print Network

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.

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

2008-06-11

274

Coherent sensing of a mechanical resonator with a single-spin qubit.  

PubMed

Mechanical systems can be influenced by a wide variety of small forces, ranging from gravitational to optical, electrical, and magnetic. When mechanical resonators are scaled down to nanometer-scale dimensions, these forces can be harnessed to enable coupling to individual quantum systems. We demonstrate that the coherent evolution of a single electronic spin associated with a nitrogen vacancy center in diamond can be coupled to the motion of a magnetized mechanical resonator. Coherent manipulation of the spin is used to sense driven and Brownian motion of the resonator under ambient conditions with a precision below 6 picometers. With future improvements, this technique could be used to detect mechanical zero-point fluctuations, realize strong spin-phonon coupling at a single quantum level, and implement quantum spin transducers. PMID:22362881

Kolkowitz, Shimon; Jayich, Ania C Bleszynski; Unterreithmeier, Quirin P; Bennett, Steven D; Rabl, Peter; Harris, J G E; Lukin, Mikhail D

2012-03-30

275

Coherent Sensing of a Mechanical Resonator with a Single-Spin Qubit  

NASA Astrophysics Data System (ADS)

Mechanical systems can be influenced by a wide variety of small forces, ranging from gravitational to optical, electrical, and magnetic. When mechanical resonators are scaled down to nanometer-scale dimensions, these forces can be harnessed to enable coupling to individual quantum systems. We demonstrate that the coherent evolution of a single electronic spin associated with a nitrogen vacancy center in diamond can be coupled to the motion of a magnetized mechanical resonator. Coherent manipulation of the spin is used to sense driven and Brownian motion of the resonator under ambient conditions with a precision below 6 picometers. With future improvements, this technique could be used to detect mechanical zero-point fluctuations, realize strong spin-phonon coupling at a single quantum level, and implement quantum spin transducers.

Kolkowitz, Shimon; Bleszynski Jayich, Ania C.; Unterreithmeier, Quirin P.; Bennett, Steven D.; Rabl, Peter; Harris, J. G. E.; Lukin, Mikhail D.

2012-03-01

276

Probing the motion of a mechanical resonator via coherent coupling to a single spin qubit  

NASA Astrophysics Data System (ADS)

Mechanical systems can be influenced by a wide variety of extremely small forces, ranging from gravitational to optical, electrical, and magnetic. When mechanical resonators are scaled down to nanometer-scale dimensions, these forces can be harnessed to enable coupling to individual quantum systems. In this talk we will present results showing that the coherent evolution of a single electronic spin associated with a Nitrogen Vacancy (NV) center in diamond can be coupled to the motion of a magnetized mechanical resonator. Specifically we use coherent manipulation of the spin to sense the driven and Brownian motion of the resonator under ambient conditions at a picometer length scale. We will discuss potential applications of this technique including the decetion of the zero-point fluctuations of a mechanical resonator, the realization of strong spin-phonon coupling at a single quantum level, and the implementation of quantum spin transducers.

Kolkowitz, Shimon; Unterreithmeier, Quirin; Bleszynski Jayich, Ania; Bennett, Steven; Rabl, Peter; Harris, J. G. E.; Lukin, Mikhail

2012-02-01

277

Single-spin asymmetries in inclusive DIS and in hadronic collisions  

NASA Astrophysics Data System (ADS)

Transverse single-spin asymmetries in inclusive deep inelastic lepton-nucleon scattering can be generated through multi-photon exchange between the leptonic and the hadronic part of the process. Here we consider two-photon exchange and mainly focus on the transverse target spin asymmetry. In particular, we investigate the case where two photons couple to different quarks. Such a contribution involves a quark-photon-quark correlator in the nucleon, which has a (modeldependent) relation to the Efremov-Teryaev-Qiu-Sterman quark-gluon-quark correlator TF. Using different parameterizations for TF we compute the transverse target spin asymmetries for both a proton and a neutron target and compare the results to recent experimental data. In addition, potential implications for our general understanding of single-spin asymmetries in hard scattering processes are discussed.

Metz, Andreas; Pitonyak, Daniel; Schäfer, Andreas; Schlegel, Marc; Vogelsang, Werner; Zhou, Jian

2013-04-01

278

Single Spin Asymmetries in Inclusive Dis and Multi-Parton Correlations in the Nucleon  

NASA Astrophysics Data System (ADS)

Transverse single spin asymmetries in inclusive deep-inelastic lepton-nucleon scattering can be generated through multi-photon exchange between the leptonic and the hadronic part of the process. Here we consider two-photon exchange, and mainly focus on the transverse target spin asymmetry. In particular, we investigate the case where two photons couple to different quarks. Such a contribution involves a quark-photon-quark correlator in the nucleon, which has a (model-dependent) relation to the Efremov-Teryaev-Qiu-Sterman quark-gluon-quark correlator TF. Using different parameterizations for TF we compute the transverse target spin asymmetry for both a proton and a neutron target, and compare the results to recent experimental data. Potential implications on our general understanding of single spin asymmetries in hard scattering processes are discussed as well.

Metz, Andreas; Pitonyak, Daniel; Schäfer, Andreas; Schlegel, Marc; Vogelsang, Werner; Zhou, Jian

279

Single-spin asymmetries in inclusive deep inelastic scattering and multiparton correlations in the nucleon  

NASA Astrophysics Data System (ADS)

Transverse single-spin asymmetries in inclusive deep inelastic lepton-nucleon scattering can be generated through multiphoton exchange between the leptonic and the hadronic part of the process. Here we consider the two-photon exchange and mainly focus on the transverse target spin asymmetry. In particular, we investigate the case where two photons couple to different quarks. Such a contribution involves a quark-photon-quark correlator in the nucleon, which has a (model-dependent) relation to the Efremov-Teryaev-Qiu-Sterman quark-gluon-quark correlator TF. Using different parametrizations for TF we compute the transverse target spin asymmetries for both a proton and a neutron target and compare the results to recent experimental data. In addition, potential implications for our general understanding of single-spin asymmetries in hard scattering processes are discussed.

Metz, A.; Pitonyak, D.; Schäfer, A.; Schlegel, M.; Vogelsang, W.; Zhou, J.

2012-11-01

280

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

281

Determination of spin Hamiltonians from projected single reference configuration interaction calculations. I. Spin 1/2 systems.  

PubMed

The most reliable wave-function based treatments of magnetic systems usually start from a complete active space self-consistent field calculation of the magnetic electrons in the magnetic orbitals, followed by extensive and expensive configuration interaction (CI) calculations. This second step, which introduces crucial spin polarization and dynamic correlation effects, is necessary to reach reliable values of the magnetic coupling constants. The computational cost of these approaches increases exponentially with the number of unpaired electrons. The single-determinantal unrestricted density functional Kohn-Sham calculations are computationally much simpler, and may provide reasonable estimates of these quantities, but their results are strongly dependent on the chosen exchange-correlation potential. The present work, which may be seen as an ab initio transcription of the unrestricted density functional theory technique, returns to the perturbative definition of the Heisenberg Hamiltonian as an effective Hamiltonian, and proposes a direct estimate of its diagonal energies through single reference CI calculations. The differences between these diagonal terms actually determine the entire Heisenberg Hamiltonian. The reference determinants must be vectors of the model space and the components on the other vectors of the model space are cancelled along the iterative process. The method is successfully tested on a series of bicentric and multicentric spin 12 systems. The projected single reference difference dedicated CI treatment is both accurate and of moderate cost. It opens the way to parameter-free calculations of large spin assemblies. PMID:20687632

Monari, A; Maynau, D; Malrieu, J-P

2010-07-28

282

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

NASA Astrophysics Data System (ADS)

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

Simmons, Christie

2012-02-01

283

From special unitary groups SU/(2I+1) to nuclear spin statistical weights  

NASA Astrophysics Data System (ADS)

Following a suggestion of S.R. Polo, Galbraith [J. Chem. Phys. 68 (1978) 1677] was the first to obtain nuclear spin statistical weights for molecules of the type XY4 (T d) , XY5 (D 3h) , and XY6 (O h) starting from special unitary groups. In the present contribution, an analogous but simpler method is presented allowing the calculation of nuclear spin statistical weights of rigid molecules belonging to all important molecular point groups. The molecules under consideration may contain more than one set of identical nuclei with spins up to 3. The method proposed can easily be extended to nonrigid molecules.

Ruoff, A.

2003-06-01

284

Magnetic field induced discontinuous spin reorientation in ErFeO{sub 3} single crystal  

SciTech Connect

The spin reorientation of ErFeO{sub 3} that spontaneously occurs at low temperature has been previously determined to be a process involving the continuous rotation of Fe{sup 3+} spins. In this work, the dynamic process of spin reorientation in ErFeO{sub 3} single crystal has been investigated by AC susceptibility measurements at various frequencies and static magnetic fields. Interestingly, two completely discontinuous steps are induced by a relatively large static magnetic field due to the variation in the magnetic anisotropy during this process. It provides deeper insights into the intriguing magnetic exchange interactions which dominate the sophisticated magnetic phase transitions in the orthoferrite systems.

Shen, Hui [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China) [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2500 (Australia); Cheng, Zhenxiang, E-mail: cheng@uow.edu.au; Hong, Fang; Wang, Xiaolin [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2500 (Australia)] [Institute for Superconducting and Electronic Materials, University of Wollongong, NSW 2500 (Australia); Xu, Jiayue [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China)] [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Yuan, Shujuan; Cao, Shixun [Department of Physics, Shanghai University, Shanghai 200444 (China)] [Department of Physics, Shanghai University, Shanghai 200444 (China)

2013-11-04

285

Spin-polarized transport through single-molecule magnet Mn6 complexes  

NASA Astrophysics Data System (ADS)

The coherent transport properties of a device, constructed by sandwiching a Mn6 single-molecule magnet between two gold surfaces, are studied theoretically by using the non-equilibrium Green's function approach combined with density functional theory. Two spin states of such Mn6 complexes are explored, namely the ferromagnetically coupled configuration of the six MnIII cations, leading to the S = 12 ground state, and the low S = 4 spin state. For voltages up to 1 volt the S = 12 ground state shows a current one order of magnitude larger than that of the S = 4 state. Furthermore this is almost completely spin-polarized, since the Mn6 frontier molecular orbitals for S = 12 belong to the same spin manifold. As such the high-anisotropy Mn6 molecule appears as a promising candidate for implementing, at the single molecular level, both spin-switches and low-temperature spin-valves.The coherent transport properties of a device, constructed by sandwiching a Mn6 single-molecule magnet between two gold surfaces, are studied theoretically by using the non-equilibrium Green's function approach combined with density functional theory. Two spin states of such Mn6 complexes are explored, namely the ferromagnetically coupled configuration of the six MnIII cations, leading to the S = 12 ground state, and the low S = 4 spin state. For voltages up to 1 volt the S = 12 ground state shows a current one order of magnitude larger than that of the S = 4 state. Furthermore this is almost completely spin-polarized, since the Mn6 frontier molecular orbitals for S = 12 belong to the same spin manifold. As such the high-anisotropy Mn6 molecule appears as a promising candidate for implementing, at the single molecular level, both spin-switches and low-temperature spin-valves. Electronic supplementary information (ESI) available: Calculated total and projected density of states of an isolated [Mn6O2(Et-sao)6{O2CPh(Me)2}2(EtOH)6] original SMM complex (Fig. S1). Calculated total and projected density of states of an isolated [Mn6O2(Me-sao)6{O2CPh(SH)}2(MeOH)6] model complex (Fig. S2). Transmission spectra calculated at different voltages corresponding to the S = 12 and S = 4 ground states for the Mn6-Au(111) layer system (Fig. S3). Cell parameters and Cartesian coordinates of the Mn6-Au(111) layer system. See DOI: 10.1039/c3nr00054k

Cremades, Eduard; Pemmaraju, C. D.; Sanvito, Stefano; Ruiz, Eliseo

2013-05-01

286

The importance of nuclear spin diffusion as an angularly independent relaxation mechanism controlling the matrix ENDOR response of radicals in molecular crystals  

NASA Astrophysics Data System (ADS)

In the generalized matrix ENDOR line shape model [P.A. Narayana et al., J. Chem. Phys., 67, 1990 (1977)] the ENDOR intensity is controlled by the nuclear spin lattice relaxation rate formulated as an angularly dependent electron-nuclear dipolar contribution and an angularly independent intrinsic bulk nuclear relaxation contribution. Comparison of this model with single crystal data [L. Kevan et al., J. Chem. Phys., 70, 5006 (1979)] showed that the angularly independent relaxation rate must be more rapid than the intrinsic bulk nuclear relaxation rate. Here we identify the angularly independent relaxation rate with nuclear spin diffusion and apply this interpretation quantitatively to data on methyl radicals in lithium acetate dihydrate crystals and to the radiation generated CH3CH(NH3)?OOH- radical in alanine at 77 K.

Schlick, Shulamith; Kevan, Larry; Toriyama, K.; Iwasaki, M.

1981-01-01

287

Ultralong spin memory of optically excited single magnetic quantum dots  

NASA Astrophysics Data System (ADS)

We study the magnetization dynamics in CdMnTe quantum dots using subwavelength optical microscopy imaging at B =0 T. For continuous laser illumination each dot exhibits strong and unique circular polarization despite completely unpolarized ensemble emission. This implies that after an exciton recombines, the spontaneous ferromagnetic alignment of magnetic impurities persists for over 100 ?s, which is a million times longer than in CdMnTe quantum wells. The spin memory effect points toward a qualitatively different picture of magnetization dynamics in the zero-dimensional limit.

Gurung, Tak; Mackowski, Sebastian; Karczewski, Grzegorz; Jackson, Howard E.; Smith, Leigh M.

2008-10-01

288

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

E-print Network

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 center 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 center. 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 center 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.

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

2014-06-10

289

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

PubMed Central

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

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

2014-01-01

290

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

PubMed

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

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

2014-01-01

291

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

292

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

PubMed Central

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

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

293

Coherent population trapping of hyperfine-coupled single spins in diamond  

NASA Astrophysics Data System (ADS)

Coherent population trapping (CPT) provides a highly sensitive means for probing the energy level structure of an atomic system. For diamond nitrogen vacancy (NV) centers, this technique offers an alternative to the standard optically-detected magnetic resonance (ODMR) for measuring the hyperfine structure of the electronic ground states. Here, we report an experimental study using CPT to probe the hyperfine splitting of these states as well as the Autler-Townes effect induced by a strong resonant microwave field. This nuclear spin dependent CPT was also employed along with other coherent spin operations for the initialization and manipulation of hyperfine-coupled nuclear spins. In addition, the use of CPT process to incorporate NV centers into a cavity QED system will be discussed.

Golter, Andrew; Dinyari, Nima; Wang, Hailin

2013-03-01

294

Spin-asymmetry energy of nuclear matter Physik-Department T39, Technische Universitt Mnchen, D-85747 Garching, Germany  

E-print Network

Spin-asymmetry energy of nuclear matter N. Kaiser Physik-Department T39, Technische Universität the density-dependent spin-asymmetry energy S kf of isospin-symmetric nuclear matter in the three of freedom in the description of the nuclear many- body dynamics. The contributions to the energy per

Weise, Wolfram

295

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

E-print Network

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.

Martin Lohmann

2014-11-04

296

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

PubMed

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

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

2015-01-01

297

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

298

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

PubMed Central

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

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

2015-01-01

299

75 FR 65558 - Final Supplemental Environmental Impact Statement, Single Nuclear Unit at the Bellefonte Plant...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Single Nuclear Unit at the Bellefonte Plant Site, Jackson County, AL AGENCY: Tennessee...Single Nuclear Unit at the Bellefonte Plant Site (final SEIS) on September 9, 2010...location of the proposed nuclear plant site was stated incorrectly in the...

2010-10-25

300

Nuclear Spin Dynamics in Double Quantum Dots: Multi-Stability, Dynamical Polarization, Criticality and Entanglement  

E-print Network

We theoretically study the nuclear spin dynamics driven by electron transport and hyperfine interaction in an electrically-defined double quantum dot (DQD) in the Pauli-blockade regime. We derive a master-equation-based framework and show that the coupled electron-nuclear system displays an instability towards the buildup of large nuclear spin polarization gradients in the two quantum dots. In the presence of such inhomogeneous magnetic fields, a quantum interference effect in the collective hyperfine coupling results in sizable nuclear spin entanglement between the two quantum dots in the steady state of the evolution. We investigate this effect using analytical and numerical techniques, and demonstrate its robustness under various types of imperfections.

Martin J. A. Schuetz; Eric M. Kessler; Lieven M. K. Vandersypen; J. Ignacio Cirac; Geza Giedke

2014-05-30

301

Fluctuations of the tunneling bias created by nuclear spins in molecular nanomagnet Fe-8.  

NASA Astrophysics Data System (ADS)

By now, it has been shown both theoretically and experimentally, that the fluctuations of the tunneling bias due to nuclear spins play a prominent role in the tunneling of magnetization in molecular nanoclusters Fe-8. In the present work, we develop the theoretical description of these fluctuations. Our result is that the fluctuation spectrum of the ``nuclear'' bias has two components: fast and slow. The fast component is due to the misalignment between the direction of the local magnetic field and the nuclear spin projection that contributes to the bias, while the slow component is due to the diffusion of the Zeeman energy of nuclear spins across the crystal. We have computed the time-dependent correlation functions associated with the both components of the fluctuation spectrum.

Fine, Boris; Tupitsyn, Igor; Stamp, Philip

2002-03-01

302

hal-00133055,version1-29Mar2007 Nuclear spin interferences in bulk water at room temperature.  

E-print Network

hal-00133055,version1-29Mar2007 Nuclear spin interferences in bulk water at room temperature. J in NMR pacs 03.67.-a: Quantum information pacs 67.57.Lm: Spin dynamics Abstract Nuclear spin interference in a static mag- netic field B0 4.7 T. For a homogeneity of B0 of the order of B0/B0 = 2 · 10-8 , the nuclear

Boyer, Edmond

303

Spin-labeled heparins as polarizing agents for dynamic nuclear polarization.  

PubMed

A potentially biocompatible class of spin-labeled macromolecules, spin-labeled (SL) heparins, and their use as nuclear magnetic resonance (NMR) signal enhancers are introduced. The signal enhancement is achieved through Overhauser-type dynamic nuclear polarization (DNP). All presented SL-heparins show high (1)H DNP enhancement factors up to E=-110, which validates that effectively more than one hyperfine line can be saturated even for spin-labeled polarizing agents. The parameters for the Overhauser-type DNP are determined and discussed. A striking result is that for spin-labeled heparins, the off-resonant electron paramagnetic resonance (EPR) hyperfine lines contribute a non-negligible part to the total saturation, even in the absence of Heisenberg spin exchange (HSE) and electron spin-nuclear spin relaxation (T(1ne)). As a result, we conclude that one can optimize the use of, for example, biomacromolecules for DNP, for which only small sample amounts are available, by using heterogeneously distributed radicals attached to the molecule. PMID:20960494

Dollmann, Björn C; Kleschyov, Andrei L; Sen, Vasily; Golubev, Valery; Schreiber, Laura M; Spiess, Hans W; Münnemann, Kerstin; Hinderberger, Dariush

2010-12-01

304

Transport through artificial single-molecule magnets: Spin-pair state sequential tunneling and Kondo effects  

NASA Astrophysics Data System (ADS)

The transport properties of an artificial single-molecule magnet based on a CdTe quantum dot doped with a single Mn+2 ion (S=5/2) are investigated by the non-equilibrium Green function method. We consider a minimal model where the Mn—hole exchange coupling is strongly anisotropic so that spin-flip is suppressed and the impurity spin S and a hole spin s entering the quantum dot are coupled into spin pair states with (2S+1) sublevels. In the sequential tunneling regime, the differential conductance exhibits (2S+1) possible peaks, corresponding to resonance tunneling via (2S+1) sublevels. At low temperature, Kondo physics dominates transport and (2S+1) Kondo peaks occur in the local density of states and conductance. These peaks originate from the spin-singlet state formed by the holes in the leads and on the dot via higher-order processes and are related to the parallel and antiparallel spin pair states.

Niu, Peng-Bin; Wang, Qiang; Nie, Yi-Hang

2013-02-01

305

Nuclear spin lattice relaxation and electric field gradient in liquid indium†  

Microsoft Academic Search

We have measured the nuclear spin lattice relaxation time in liquid indium from 130°C to 300°C to be: 1\\/T1=(1.98 × 0.0082T) × 103 sec-1. The relaxation rate consists of two significant parts: (1\\/T1)K from the nuclear magnetic hyperfine interaction, and (1\\/T1)Q from the nuclear quadrupole interaction. We calculate (1\\/T1)K from the the modified Korringa relation using a correction factor of

F. A. Rossini; E. Geissler; E. M. Dickson; W. D. Knight

1967-01-01

306

Nuclear spin lattice relaxation and electric field gradient in liquid indium  

Microsoft Academic Search

We have measured the nuclear spin lattice relaxation time in liquid indium from 130°C to 300°C to be: 1\\/T1=(1.98 × 0.0082T) × 10 sec. The relaxation rate consists of two significant parts: (1\\/T1)K from the nuclear magnetic hyperfine interaction, and (1\\/T1)Q from the nuclear quadrupole interaction. We calculate (1\\/T1)K from the the modified Korringa relation using a correction factor of

F. A. Rossini; E. Geissler; E. M. Dickson; W. D. Knight

1967-01-01

307

TAUTOMERISM AND SITE OF PROTONATION OF 1-METHYLCYTOSINE: PROOF BY NUCLEAR MAGNETIC RESONANCE SPIN-SPIN COUPLING.  

PubMed

New nuclear magnetic resonance data lead to a completely unambiguous proof that the predominant tautomeric form of 1-methylcytosine is the amino form and that in acid solution the molecule protonates at 3-N. The close similarity of the nuclear magnetic resonance spectra of this compound to the spectra of the cytosine nucleosides indicates that these structures also exist in the nucleosides. These conclusions are reached on the basis of the spectra of analogs labeled with N15 and of the proton spin decoupling measurements made at low temperature. PMID:14075685

MILES, H T; BRADLEY, R B; BECKER, E D

1963-12-20

308

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

SciTech Connect

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.

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

309

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

PubMed

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 [Formula: see text]. 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

Toth, S; Lake, B

2015-04-29

310

Robust control of entanglement in a Nitrogen-vacancy centre coupled to a Carbon-13 nuclear spin in diamond  

E-print Network

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.

R. S. Said; J. Twamley

2009-03-23

311

Mesoscopic effects in a single-mode Datta-Das spin field-effect transistor  

NASA Astrophysics Data System (ADS)

We study a single-mode Datta-Das spin field-effect transistor (SFET) in the presence (absence) of impurity scattering and external magnetic fields, and find interesting mesoscopic effects such as peak splitting, phase locking, and period halving. Experimental observation of these effects appears to be feasible in a single-mode SFET made of materials such as InGaAs/InAlAs .

Lee, Hyun-Woo; Çal??kan, S.; Park, Hyowon

2005-10-01

312

Shot Noise as a Probe of Spin-Polarized Transport through Single Atoms  

NASA Astrophysics Data System (ADS)

Single atoms on Au(111) surfaces have been contacted with the Au tip of a low temperature scanning tunneling microscope. The shot noise of the current through these contacts has been measured up to frequencies of 120 kHz and Fano factors have been determined to characterize the transport channels. The noise at Fe and Co atoms, the latter displaying a Kondo effect, indicates spin-polarized transport through a single channel. Transport calculations reproduce this observation.

Burtzlaff, Andreas; Weismann, Alexander; Brandbyge, Mads; Berndt, Richard

2015-01-01

313

Separation and conversion dynamics of nuclear-spin isomers of gaseous methanol.  

PubMed

All symmetrical molecules with non-zero nuclear spin exist in nature as nuclear-spin isomers (NSIs). However, owing to the lack of experimental information, knowledge is rare about interconversions of NSIs of gaseous molecules with torsional symmetry. Here we report our separation and conversion observations on NSI-torsion-specific transition systems of gaseous methanol from a light-induced drift experiment involving partially spatial separation of the ortho and para isomers. We find that vibrationally excited molecules of the methanol spin isomer have a smaller collision cross-section than their ground-state counterparts. Interconversion of the enriched ortho isomer with the para isomer, which is generally considered improbable, has been quantitatively studied by sensitive detections of the spectral intensities. Rather counterintuitively, this reveals that the interconversion is inhibited with increasing pressure. Our results suggest that the spin conversion mechanism in methanol is via a quantum relaxation process with the quantum Zeno effect induced by molecular collisions. PMID:25880882

Sun, Zhen-Dong; Ge, Meihua; Zheng, Yujun

2015-01-01

314

Single and Multi-Nucleon Transfer Reactions for Nuclear Moment Studies Toward Radioactive-Ion Beams  

SciTech Connect

This study is a part of an experimental program to measure nuclear moments in transfer reactions. It aims to probe for a first time the nuclear -spin orientation in multi-nucleon transfer. Fist experiments were performed to measure the quadrupole moment of an isomeric state in {sup 66}Cu (I{sup p}i 6{sup -}, E{sub x} = 1154 keV, T{sub 1/2} = 595(20) ns) in single nucleon transfer and the population of mus isomers in {sup 66}Cu and {sup 63}Ni in multi-nucleon transfer. The experimentally tested methodology allows broad applications toward more exotic species and feasibility of these reactions to produce species away from stability.

Lozeva, R. L.; Georgiev, G. P.; Audi, G.; Cabaret, S.; Fiori, E.; Gaulard, C.; Hauschilda, K.; Lopez-Martens, A.; Risegari, L. [CSNSM, Universite Paris-Sud 11, CNRS/IN2P3, F-91405 Orsay-Campus (France); Balabanski, D. L. [INRNE, Bulgarian Academy of Sciences, BG-1784 Sofia (Bulgaria); Blazhev, A.; Jolie, J.; Moschner, K.; Zell, K.-O. [IKP, Universitaet zu Koeln, DE-50937 Cologne (Germany); Daugas, J.-M.; Faul, T.; Morel, P.; Roig, O. [CEA, DAM, DIF, F-91297 Arpajon Cedex (France); Ferraton, M.; Ibrahim, F. [IPN, CNRS/IN2P3, F-91406 Orsay-Campus (France)

2010-04-30

315

The magnetic properties of the spin-1 Heisenberg antiferromagnetic chain with single-ion anisotropy  

NASA Astrophysics Data System (ADS)

The magnetic properties of the spin-1 Heisenberg antiferromagnetic chain with exchange anisotropy and single-ion anisotropy are studied by the double-time Green's function method. The determinative equations for the critical temperature, the magnetization, and the zero-field susceptibility are derived analytically. The effects of the anisotropies on the magnetic properties are presented.

Hu, Gangsan; Zhu, Rengui

2015-02-01

316

Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves  

SciTech Connect

We report solid state {sup 13}C and {sup 1}H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, {sup 1}H and cross-polarized {sup 13}C NMR signals from {sup 15}N,{sup 13}C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T{sub 1e} is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations.

Thurber, Kent R., E-mail: thurberk@niddk.nih.gov; Tycko, Robert [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520 (United States)] [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520 (United States)

2014-05-14

317

Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves.  

PubMed

We report solid state (13)C and (1)H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, (1)H and cross-polarized (13)C NMR signals from (15)N,(13)C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T1e is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations. PMID:24832263

Thurber, Kent R; Tycko, Robert

2014-05-14

318

Universal Long-time Behavior of Nuclear Spin Decays in a Solid  

E-print Network

Magnetic resonance studies of nuclear spins in solids are exceptionally well suited to probe the limits of statistical physics. We report experimental results indicating that isolated macroscopic systems of interacting nuclear spins possess the following fundamental property: spin decays that start from different initial configurations quickly evolve towards the same long-time behavior. This long-time behavior is characterized by the shortest ballistic microscopic timescale of the system and therefore falls outside of the validity range for conventional approximations of statistical physics. We find that the nuclear free induction decay and different solid echoes in hyperpolarized solid xenon all exhibit sinusoidally modulated exponential long-time behavior characterized by identical time constants. This universality was previously predicted on the basis of analogy with resonances in classical chaotic systems.

Steven W. Morgan; Boris V. Fine; Brian Saam

2008-05-13

319

Sideband cooling while preserving coherences in the nuclear spin state in group-II-like atoms.  

PubMed

We propose a method for laser cooling group-II-like atoms without changing the quantum state of their nuclear spins, thus preserving coherences that are usually destroyed by optical pumping in the cooling process. As group-II-like atoms have a (1)S(0) closed-shell ground state, nuclear spin and electronic angular momentum are decoupled, allowing for their independent manipulation. The hyperfine interaction that couples these degrees of freedom in excited states can be suppressed through the application of external magnetic fields. Our protocol employs resolved-sideband cooling on the forbidden clock transition, (1)S(0) --> (3)P(0), with quenching via coupling to the rapidly decaying (1)P(1) state, deep in the Paschen-Back regime. This makes it possible to laser cool neutral atomic qubits without destroying the quantum information stored in their nuclear spins, as shown in two examples, (171)Yb and (87)Sr. PMID:17930500

Reichenbach, Iris; Deutsch, Ivan H

2007-09-21

320

Theory for cross effect dynamic nuclear polarization under magic-angle spinning in solid state nuclear magnetic resonance: The importance of level crossings  

NASA Astrophysics Data System (ADS)

We present theoretical calculations of dynamic nuclear polarization (DNP) due to the cross effect in nuclear magnetic resonance under magic-angle spinning (MAS). Using a three-spin model (two electrons and one nucleus), cross effect DNP with MAS for electron spins with a large g-anisotropy can be seen as a series of spin transitions at avoided crossings of the energy levels, with varying degrees of adiabaticity. If the electron spin-lattice relaxation time T1e is large relative to the MAS rotation period, the cross effect can happen as two separate events: (i) partial saturation of one electron spin by the applied microwaves as one electron spin resonance (ESR) frequency crosses the microwave frequency and (ii) flip of all three spins, when the difference of the two ESR frequencies crosses the nuclear frequency, which transfers polarization to the nuclear spin if the two electron spins have different polarizations. In addition, adiabatic level crossings at which the two ESR frequencies become equal serve to maintain non-uniform saturation across the ESR line. We present analytical results based on the Landau-Zener theory of adiabatic transitions, as well as numerical quantum mechanical calculations for the evolution of the time-dependent three-spin system. These calculations provide insight into the dependence of cross effect DNP on various experimental parameters, including MAS frequency, microwave field strength, spin relaxation rates, hyperfine and electron-electron dipole coupling strengths, and the nature of the biradical dopants.

Thurber, Kent R.; Tycko, Robert

2012-08-01

321

Spin and temperature dependence of nuclear deformation using alpha-gamma angular correlations  

Microsoft Academic Search

Alpha-particle angular distributions with respect to the spin direction of residual nuclei have been measured in heavy-ion fusion reactions. The spin direction was determined by measuring the ..gamma..-ray angular distributions, for each event, using the spin spectrometer. ..cap alpha..-particle anisotropies have been extracted for the compound nuclear systems: ¹¹°Sn*(94 MeV), ¹¹⁴Sn*(80 MeV), ¹³⁸Nd*(82 MeV), ¹⁶⁴Yb*(67 MeV) and ¹⁷°Yb*(135 MeV) as

N. G. Nicolis; D. G. Sarantites; L. A. Adler; F. A. Dilmanian; K. Honkanen; Z. Majka; L. G. Sobotka; Z. Li; T. M. Semkow; J. R. Beene

1987-01-01

322

Effect of electron spin dynamics on solid-state dynamic nuclear polarization performance.  

PubMed

For the broadest dissemination of solid-state dynamic nuclear polarization (ssDNP) enhanced NMR as a material characterization tool, the ability to employ generic mono-nitroxide radicals as spin probes is critical. A better understanding of the factors contributing to ssDNP efficiency is needed to rationally optimize the experimental condition for the practically accessible spin probes at hand. This study seeks to advance the mechanistic understanding of ssDNP by examining the effect of electron spin dynamics on ssDNP performance at liquid helium temperatures (4-40 K). The key observation is that bi-radicals and mono-radicals can generate comparable nuclear spin polarization at 4 K and 7 T, which is in contrast to the observation for ssDNP at liquid nitrogen temperatures (80-150 K) that finds bi-radicals to clearly outperform mono-radicals. To rationalize this observation, we analyze the change in the DNP-induced nuclear spin polarization (Pn) and the characteristic ssDNP signal buildup time as a function of electron spin relaxation rates that are modulated by the mono- and bi-radical spin concentration. Changes in Pn are consistent with a systematic variation in the product of the electron spin-lattice relaxation time and the electron spin flip-flop rate that constitutes an integral saturation factor of an inhomogeneously broadened EPR spectrum. We show that the comparable Pn achieved with both radical species can be reconciled with a comparable integral EPR saturation factor. Surprisingly, the largest Pn is observed at an intermediate spin concentration for both mono- and bi-radicals. At the highest radical concentration, the stronger inter-electron spin dipolar coupling favors ssDNP, while oversaturation diminishes Pn, as experimentally verified by the observation of a maximum Pn at an intermediate, not the maximum, microwave (?w) power. At the maximum ?w power, oversaturation reduces the electron spin population differential that must be upheld between electron spins that span a frequency difference matching the (1)H NMR frequency-characteristic of the cross effect DNP. This new mechanistic insight allows us to rationalize experimental conditions where generic mono-nitroxide probes can offer competitive ssDNP performance to that of custom designed bi-radicals, and thus helps to vastly expand the application scope of ssDNP for the study of functional materials and solids. PMID:24968276

Siaw, Ting Ann; Fehr, Matthias; Lund, Alicia; Latimer, Allegra; Walker, Shamon A; Edwards, Devin T; Han, Song-I

2014-09-21

323

Coupling a single spin in diamond to the quantum motion of a mechanical cantilever  

NASA Astrophysics Data System (ADS)

We present theoretical considerations for a magnetized mechanical cantilever coupled to a single electronic spin associated with a nitrogen-vacancy (NV) defect center in diamond. This coupled system has recently been implemented in an experiment where the NV spin was used to detect the thermal motion of a magnetic force microscope cantilever at room temperature, reading out the spin state optically using the spin-selective fluorescence of the NV. The possibility to extend this system to the quantum regime opens the door to applications such as readout and transfer of quantum information, as well as interesting theoretical questions. For example, it should be possible to reach the regime of strong coupling between the spin and the motion of the cantilever, in analogy to cavity quantum electrodynamics. We discuss the prospects for reaching the strong coupling regime and the conditions for measuring the onset of quantum effects, such as measuring the zero point motion of the cantilever using the spin as a detector.

Bennett, Steven; Kolkowitz, Shimon; Unterreithmeier, Quirin; Rabl, Peter; Bleszynski-Jayich, Ania; Harris, Jack; Lukin, Mikhail

2012-02-01

324

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

SciTech Connect

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.

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

325

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

NASA Astrophysics Data System (ADS)

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.

Wagner, Andreas; Bruder, Christoph; Demler, Eugene

2011-12-01

326

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

E-print Network

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.

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

2010-03-29

327

Spin gap in the single spin-1/2 chain cuprate Sr1.9Ca0.1CuO3  

NASA Astrophysics Data System (ADS)

We report Cu63 nuclear magnetic resonance and muon spin rotation measurements on the S =1/2 antiferromagnetic Heisenberg spin chain compound Sr1.9Ca0.1CuO3. An exponentially decreasing spin-lattice relaxation rate T1-1 indicates the opening of a spin gap. This behavior is very similar to what has been observed for the cognate zigzag spin chain compound Sr0.9Ca0.1CuO2, and it confirms that the occurrence of a spin gap upon Ca doping is independent of the interchain exchange coupling J'. Our results therefore suggest that the appearance of a spin gap in an antiferromagnetic Heisenberg spin chain is induced by a local bond disorder of the intrachain exchange coupling J. A low-temperature upturn of T1-1 evidences growing magnetic correlations. However, zero-field muon spin rotation measurements down to 1.5 K confirm the absence of magnetic order in this compound, which is most likely suppressed by the opening of the spin gap.

Hammerath, F.; Brüning, E. M.; Sanna, S.; Utz, Y.; Beesetty, N. S.; Saint-Martin, R.; Revcolevschi, A.; Hess, C.; Büchner, B.; Grafe, H.-J.

2014-05-01

328

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

E-print Network

We generalize the method of our recent paper on 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.

Emmanuel Floratos; Georgios Linardopoulos

2014-09-12

329

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

Microsoft Academic Search

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

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

2007-01-01

330

Twist-three Fragmentation Function Contribution to the Single Spin Asymmetry in pp Collisions  

SciTech Connect

We study the twist-three fragmentation function contribution to the single transverse spin asymmetries in inclusive hadron production in pp collisions, pp->h+X. In particular, we evaluate the so-called derivative contribution which dominates the spin asymmetry in the forward direction of the polarized proton. With certain parametrizations for the twist-three fragmentation function, we estimate its contribution to the asymmetry of pi0 production at RHIC energy. We find that the contribution is sizable and might be responsible for the big difference between the asymmetries in eta and pi0 productions observed by the STAR collaboration at RHIC.

Kang, Zhong-Bo; Yuan, Feng; Zhou, Jian

2010-01-29

331

Single nuclear pores visualized by confocal microscopy and image processing.  

PubMed Central

How nuclear pore complexes, mediating the transport of nucleic acids, proteins, and metabolites between cell nucleus and cytoplasm, are arranged in the nuclear envelope is essentially unknown. Here we describe a method combining high-resolution confocal imaging with image processing and pattern recognition to visualize single nuclear pore complexes (120 nm diameter), determine their relative positions with nanometer accuracy, and analyze their distribution in situ. The method was tested by means of a model system in which the very same sample areas could be imaged by confocal and electron microscopy. It was thus found that single fluorescent beads of 105 nm nominal diameter could be localized with a lateral accuracy of <20 nm and an axial accuracy of approximately 20 nm. The method was applied to digitonin-permeabilized 3T3 cells, whose nuclear pore complexes were fluorescently labeled with the anti-nucleoporin antibody mAb414. Stacks of optical sections were generated by confocal imaging at high resolution. Herein the nuclear pore complexes appeared as bright diffraction-limited spots whose centers were localized by fitting them by three-dimensional gaussians. The nearest-neighbor distribution function and the pair correlation function were calculated and found to agree well with those of randomly distributed hard cylinders of 138 +/- 17 nm diameter, but not with those of randomly distributed points or nonrandomly distributed cylinders. This was supported by a cluster analysis. Implications for the direct observation of the transport of single particles and molecules through individual nuclear pore complexes are discussed. Images FIGURE 1 FIGURE 2 FIGURE 4 PMID:9172731

Kubitscheck, U; Wedekind, P; Zeidler, O; Grote, M; Peters, R

1996-01-01

332

Studies of nuclear rotational bands with the spin spectrometer  

Microsoft Academic Search

In the last few years increasingly sophisticated gamma-ray spectrometer arrays have been built at a number of laboratories around the world. These instruments, coupled with versatile heavy-ion accelerators, are capable of probing the detailed behaviour of atomic nuclei under extreme conditions of angular momentum and temperature. Characteristics of one such detector array, the Spin Spectrometer at Oak Ridge National Laboratory,

L. L. Riedinger; M. P. Carpenter; L. H. Courtney; V. P. Janzen

1987-01-01

333

Optically detected coherent spin dynamics of a single electron in a quantum dot  

E-print Network

the sample, analogous to the Faraday effect for transmitted light. For a probe laser energy E, the KR angle dynamics provide a sensitive probe of the local nuclear spin environment. The magneto-optical Kerr effect.5 ns Ti:sapphire II Pump 0 4 8 12 Ti:sapphire I EOM Sample Probe Pump Pol. BS x z y PL(a.u.) XX X­ ­20

Loss, Daniel

334

Fast Nuclear Spin Hyperpolarization of Phosphorus in Silicon D. R. McCamey,1,* J. van Tol,2  

E-print Network

is important for a number of its applications. Utilizing the nuclear spin of phosphorus donors as quantum bitsFast Nuclear Spin Hyperpolarization of Phosphorus in Silicon D. R. McCamey,1,* J. van Tol,2 G. W of phosphorus donors in silicon. This polarization is reached with a time constant of $150 sec

McCamey, Dane

335

Microwave Field Distribution in a Magic Angle Spinning Dynamic Nuclear Polarization NMR Probe  

PubMed Central

We present a calculation of the microwave field distribution in a magic angle spinning (MAS) probe utilized in dynamic nuclear polarization (DNP) experiments. The microwave magnetic field (B1S) profile was obtained from simulations performed with the High Frequency Structure Simulator (HFSS) software suite, using a model that includes the launching antenna, the outer Kel-F stator housing coated with Ag, the RF coil, and the 4 mm diameter sapphire rotor containing the sample. The predicted average B1S field is 13µT/W1/2, where S denotes the electron spin. For a routinely achievable input power of 5 W the corresponding value is ? SB1S = 0.84 MHz. The calculations provide insights into the coupling of the microwave power to the sample, including reflections from the RF coil and diffraction of the power transmitted through the coil. The variation of enhancement with rotor wall thickness was also successfully simulated. A second, simplified calculation was performed using a single pass model based on Gaussian beam propagation and Fresnel diffraction. This model provided additional physical insight and was in good agreement with the full HFSS simulation. These calculations indicate approaches to increasing the coupling of the microwave power to the sample, including the use of a converging lens and fine adjustment of the spacing of the windings of the RF coil. The present results should prove useful in optimizing the coupling of microwave power to the sample in future DNP experiments. Finally, the results of the simulation were used to predict the cross effect DNP enhancement (?) vs. ?1S/(2?) for a sample of 13C-urea dissolved in a 60:40 glycerol/water mixture containing the polarizing agent TOTAPOL; very good agreement was obtained between theory and experiment. PMID:21382733

Nanni, Emilio A.; Barnes, Alexander B.; Matsuki, Yoh; Woskov, Paul P.; Corzilius, Björn; Griffin, Robert G.; Temkin, Richard J.

2011-01-01

336

Dynamical Monte Carlo investigation of spin reversals and nonequilibrium magnetization of single-molecule magnets  

E-print Network

In this paper, we combine thermal effects with Landau-Zener (LZ) quantum tunneling effects in a dynamical Monte Carlo (DMC) framework to produce satisfactory magnetization curves of single-molecule magnet (SMM) systems. We use the giant spin approximation for SMM spins and consider regular lattices of SMMs with magnetic dipolar interactions (MDI). We calculate spin reversal probabilities from thermal-activated barrier hurdling, direct LZ tunneling, and thermal-assisted LZ tunnelings in the presence of sweeping magnetic fields. We do systematical DMC simulations for Mn12 -ac systems with various temperatures and sweeping field rates. Our simulations produce clear step structures in low-temperature magnetization curves, and our results show that the thermally activated barrier hurdling becomes dominating at high temperature near 3K and the thermal-assisted tunnelings play important roles at intermediate temperature. Our magnetization curves are satisfactory compared to experimental results, considering possible...

Liu, Gui-Bin

2010-01-01

337

Measurement of z-direction component of electron spins field-emitted from a single-crystal magnetite whisker.  

PubMed

A 90° sector type spin rotator was developed for measurement of the z-direction component of a spin polarization, which is parallel to the emitter axis. The rotator enables us to measure all components of electron spins field-emitted from a single crystalline magnetite. In-plane component of spin polarization dominated of field-emitted electrons from single crystalline magnetite whisker, thus it is suggested that the magnetization of the magnetite whisker results from the anisotropy of crystalline structure rather than its shape. PMID:21664540

Nagai, S; Sakakibara, H; Hata, K; Okada, M; Mimura, H

2011-05-01

338

Coupled nuclear spin relaxation and internal rotations in magnesium fluosilicate hexahydrate.  

NASA Technical Reports Server (NTRS)

Both proton and fluorine nuclear spin-lattice relaxations have been studied by the 180- to 90-deg pulse method in magnesium fluosilicate hexahydrate at 25 and 13 MHz over the temperature range from 170 to 350 K. Observed nonexponential behavior of the nuclear magnetic relaxation is explained by internal rotations of the doubly charged negative fluosilicate ions and doubly charged positive magnesium hexahydrate ions.

Utton, D. B.; Tsang, T.

1972-01-01

339

Scalable spin amplification with a gain over a hundred.  

PubMed

We propose a scalable and practical implementation of spin amplification which does not require individual addressing nor a specially tailored spin network. We have demonstrated a gain of 140 in a solid-state nuclear spin system of which the spin polarization has been increased to 0.12 using dynamic nuclear polarization with photoexcited triplet electron spins. Spin amplification scalable to a higher gain opens the door to the single spin measurement for a readout of quantum computers as well as practical applications of nuclear magnetic resonance spectroscopy to infinitesimal samples which have been concealed by thermal noise. PMID:21867053

Negoro, Makoto; Tateishi, Kenichiro; Kagawa, Akinori; Kitagawa, Masahiro

2011-07-29

340

Nuclear-Powered Millisecond Pulsars and the Maximum Spin Frequency of Neutron Stars  

E-print Network

Millisecond pulsars are neutron stars (NSs) that are thought to have been spun-up by mass accretion from a stellar companion. It is unknown whether there is a natural brake for this process, or if it continues until the centrifugal breakup limit is reached at submillisecond periods. Many NSs that are accreting from a companion exhibit thermonuclear X-ray bursts that last tens of seconds, caused by unstable nuclear burning on their surfaces. Millisecond brightness oscillations during bursts from ten NSs (as distinct from other rapid X-ray variability that is also observed) are thought to measure the stellar spin, but direct proof of a rotational origin has been lacking. Here, we report the detection of burst oscillations at the known spin frequency of an accreting millisecond pulsar, and we show that these oscillations always have the same rotational phase. This firmly establishes burst oscillations as nuclear-powered pulsations tracing the spin of accreting NSs, corroborating earlier evidence. The distribution of spin frequencies of the 11 nuclear-powered pulsars cuts off well below the breakup frequency for most NS models, supporting theoretical predictions that gravitational radiation losses can limit accretion torques in spinning up millisecond pulsars.

Deepto Chakrabarty; Edward H. Morgan; Michael P. Muno; Duncan K. Galloway; Rudy Wijnands; Michiel van der Klis; Craig B. Markwardt

2003-07-01

341

Coherent storage of microwave excitations in rare-earth nuclear spins  

E-print Network

Interfacing between various elements of a computer - from memory to processors to long range communication - will be as critical for quantum computers as it is for classical computers today. Paramagnetic rare earth doped crystals, such as Nd$^{3+}$:Y$_2$SiO$_5$ (YSO), are excellent candidates for such a quantum interface: they are known to exhibit long optical coherence lifetimes (for communication via optical photons), possess a nuclear spin (memory) and have in addition an electron spin that can offer hybrid coupling with superconducting qubits (processing). Here we study two of these three elements, demonstrating coherent storage and retrieval between electron and $^{145}$Nd nuclear spin states in Nd$^{3+}$:YSO. We find nuclear spin coherence times can reach 9 ms at $\\approx 5$ K, about two orders of magnitude longer than the electron spin coherence, while quantum state and process tomography of the storage/retrieval operation reveal an average state fidelity of 0.86. The times and fidelities are expected to further improve at lower temperatures and with more homogeneous radio-frequency excitation.

Gary Wolfowicz; Hannes Maier-Flaig; Robert Marino; Alban Ferrier; Hervé Vezin; John J. L. Morton; Philippe Goldner

2014-12-23

342

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

SciTech Connect

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.

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

2010-07-02

343

Anomalous nuclear spin relaxation of adsorbed helium-3  

Microsoft Academic Search

Within the framework of a general theory of two-dimensional NMR we are able to elucidate certain anomalous features of spin relaxation in adsorbed and porous systems. We explain the linear dependence of relaxation time on applied magnetic field, and this is demonstrated to be related to the relative insensitivity ofT1to temperature. We also show thatT1remains field dependent on the “fast”

Brian P. Cowan

1983-01-01

344

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

NASA Astrophysics Data System (ADS)

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.

Nossa, Javier; Canali, Carlo

2013-03-01

345

Spin-wave excitations in superlattices self-assembled in multiferroic single crystals.  

PubMed

Spin-wave excitations revealed in the dynamically equilibrated one-dimensional superlattices formed due to phase separation and charge carrier self-organization in doped single crystals of Eu(0.8)Ce(0.2)Mn(2)O(5) and Tb(0.95)Bi(0.05)MnO(3) multiferroics are discussed. Similar excitations, but having lower intensities, were also observed in undoped RMn(2)O(5) (R=Eu, Er, Tb, Bi). This suggests that a charge transfer between manganese ions with different valences, which give rise to the superlattice formation, occurs in undoped multiferroics as well. The spin excitations observed in the native superlattices represent a set of homogeneous spin-wave resonances excited in individual superlattice layers. The positions of these resonances depend on the relation between the numbers of Mn(3+) and Mn(4+) ions, charge carrier concentrations, and barrier depths in the superlattice layers. It has been found that the spin-wave excitations observed in the frequency interval studied (30-50 GHz) form two spin-wave minibands with a gap between them. PMID:22872124

Sanina, V A; Golovenchits, E I; Zalesskii, V G

2012-08-29

346

Terahertz probes of magnetic field induced spin reorientation in YFeO3 single crystal  

NASA Astrophysics Data System (ADS)

Using the terahertz time-domain spectroscopy, we demonstrate the spin reorientation of a canted antiferromagnetic YFeO3 single crystal, by evaluating the temperature and magnetic field dependence of resonant frequency and amplitude for the quasi-ferromagnetic (FM) and quasi-antiferromagnetic modes (AFM), a deeper insight into the dynamics of spin reorientation in rare-earth orthoferrites is established. Due to the absence of 4f-electrons in Y ion, the spin reorientation of Fe sublattices can only be induced by the applied magnetic field, rather than temperature. In agreement with the theoretical predication, the frequency of FM mode decreases with magnetic field. In addition, an obvious step of spin reorientation phase transition occurs with a relatively large applied magnetic field of 4 T. By comparison with the family members of RFeO3 (R = Y3+ or rare-earth ions), our results suggest that the chosen of R would tailor the dynamical rotation properties of Fe ions, leading to the designable spin switching in the orthoferrite antiferromagnetic systems.

Lin, Xian; Jiang, Junjie; Jin, Zuanming; Wang, Dongyang; Tian, Zhen; Han, Jiaguang; Cheng, Zhenxiang; Ma, Guohong

2015-03-01

347

Solid effect in magic angle spinning dynamic nuclear polarization  

E-print Network

For over five decades, the solid effect (SE) has been heavily utilized as a mechanism for performing dynamic nuclear polarization (DNP). Nevertheless, it has not found widespread application in contemporary, high magnetic ...

Smith, Albert A.

348

Nuclear spin dependence of the reaction of H3+ with H2. I. Kinetics and modeling  

NASA Astrophysics Data System (ADS)

The chemical reaction H_3^+ + H2 ? H2 + H_3^+ is the simplest bimolecular reaction involving a polyatomic, yet is complex enough that exact quantum mechanical calculations to adequately model its dynamics are still unfeasible. In particular, the branching fractions for the "identity," "proton hop," and "hydrogen exchange" reaction pathways are unknown, and to date, experimental measurements of this process have been limited. In this work, the nuclear-spin-dependent steady-state kinetics of the H_3^+ + H2 reaction is examined in detail, and employed to generate models of the ortho:para ratio of H_3^+ formed in plasmas of varying ortho:para H2 ratios. One model is based entirely on nuclear spin statistics, and is appropriate for temperatures high enough to populate a large number of H_3^+ rotational states. Efforts are made to include the influence of three-body collisions in this model by deriving nuclear spin product branching fractions for the H_5^+ + H2 reaction. Another model, based on rate coefficients calculated using a microcanonical statistical approach, is appropriate for lower-temperature plasmas in which energetic considerations begin to compete with the nuclear spin branching fractions. These models serve as a theoretical framework for interpreting the results of laboratory studies on the reaction of H_3^+ with H2.

Crabtree, Kyle N.; Tom, Brian A.; McCall, Benjamin J.

2011-05-01

349

Angular dependence of nuclear spin echo decay in thin-film yttrium iron garnet  

Microsoft Academic Search

The angular dependence of the nuclear spin echo decay of 57Fe in monocrystalline thin-film Y3Fe5O12 was measured. The experimental results for the octahedral Fe3+ a-ions were explained by the orientation fluctuations of the electron magnetization about the local symmetry axis.

G. N. Abelyashev; S. N. Polulyah; V. N. Berzhanskij; N. A. Sergeev

1995-01-01

350

Radiation-induced oxidation and reduction of guanine: Electron spin resonance--electron nuclear double resonance studies of irradiated guanosine cyclic monophosphate  

SciTech Connect

Two free radicals are identified by electron spin resonance--electron nuclear double resonance (ESR-ENDOR) spectroscopy in single crystals of guanosine 3',5'-cyclic monophosphate x irradiated at 4.2 K. The two absorptions are attributed to the anion and cation formed on the guanine moiety. The characteristics of the cation absorption are consistent with those postulated previously for guanine cation presumed to form in irradiated DNA.

Kim, H.; Budzinski, E.E.; Box, H.C.

1989-02-01

351

Nuclear Spin Relaxation and Molecular Interactions of a Novel Triazolium-Based Ionic Liquid  

SciTech Connect

Nuclear spin relaxation, small-angle X-ray scattering (SAXS), and electrospray ionization mass spectrometry (ESI-MS) techniques are used to determine supramolecular arrangement of 3-methyl-1-octyl-4-phenyl-1H-triazol-1,2,3-ium bis(trifluoromethanesulfonyl)imide [OMPhTz][Tf{sub 2}N], an example of a triazolium-based ionic liquid. The results obtained showed first-order thermodynamic dependence for nuclear spin relaxation of the anion. First-order relaxation dependence is interpreted as through-bond dipolar relaxation. Greater than first-order dependence was found in the aliphatic protons, aromatic carbons (including nearest neighbors), and carbons at the end of the aliphatic tail. Greater than first order thermodynamic dependence of spin relaxation rates is interpreted as relaxation resulting from at least one mechanism additional to through-bond dipolar relaxation. In rigid portions of the cation, an additional spin relaxation mechanism is attributed to anisotropic effects, while greater than first order thermodynamic dependence of the octyl side chain’s spin relaxation rates is attributed to cation–cation interactions. Little interaction between the anion and the cation was observed by spin relaxation studies or by ESI-MS. No extended supramolecular structure was observed in this study, which was further supported by MS and SAXS. nuclear Overhauser enhancement (NOE) factors are used in conjunction with spin–lattice relaxation time (T{sub 1}) measurements to calculate rotational correlation times for C–H bonds (the time it takes for the vector represented by the bond between the two atoms to rotate by one radian). The rotational correlation times are used to represent segmental reorientation dynamics of the cation. A combination of techniques is used to determine the segmental interactions and dynamics of this example of a triazolium-based ionic liquid.

Allen, Jesse J.; Schneider, Yanika; Kail, Brian W.; Luebke, David R.; Nulwala, Hunaid; Damodaran, Krishnan

2013-04-11

352

The role of level anti-crossings in nuclear spin hyperpolarization.  

PubMed

Nuclear spin hyperpolarization is an important resource for increasing the sensitivity of NMR spectroscopy and MRI. Signal enhancements can be as large as 3-4 orders of magnitude. In hyperpolarization experiments, it is often desirable to transfer the initial polarization to other nuclei of choice, either protons or insensitive nuclei such as (13)C and (15)N. This situation arises primarily in Chemically Induced Dynamic Nuclear Polarization (CIDNP), Para-Hydrogen Induced Polarization (PHIP), and the related Signal Amplification By Reversible Exchange (SABRE). Here we review the recent literature on polarization transfer mechanisms, in particular focusing on the role of Level Anti-Crossings (LACs) therein. So-called "spontaneous" polarization transfer may occur both at low and high magnetic fields. In addition, transfer of spin polarization can be accomplished by using especially designed pulse sequences. It is now clear that at low field spontaneous polarization transfer is primarily due to coherent spin-state mixing under strong coupling conditions. However, thus far the important role of LACs in this process has not received much attention. At high magnetic field, polarization may be transferred by cross-relaxation effects. Another promising high-field technique is to generate the strong coupling condition by spin locking using strong radio-frequency fields. Here, an analysis of polarization transfer in terms of LACs in the rotating frame is very useful to predict which spin orders are transferred depending on the strength and frequency of the B1 field. Finally, we will examine the role of strong coupling and LACs in magnetic-field dependent nuclear spin relaxation and the related topic of long-lived spin-states. PMID:25142733

Ivanov, Konstantin L; Pravdivtsev, Andrey N; Yurkovskaya, Alexandra V; Vieth, Hans-Martin; Kaptein, Robert

2014-08-01

353

Coherent transfer of nuclear spin polarization in field-cycling NMR experiments  

SciTech Connect

Coherent polarization transfer effects in a coupled spin network have been studied over a wide field range. The transfer mechanism is based on exciting zero-quantum coherences between the nuclear spin states by means of non-adiabatic field jump from high to low magnetic field. Subsequent evolution of these coherences enables conversion of spin order in the system, which is monitored after field jump back to high field. Such processes are most efficient when the spin system passes through an avoided level crossing during the field variation. The polarization transfer effects have been demonstrated for N-acetyl histidine, which has five scalar coupled protons; the initial spin order has been prepared by applying RF-pulses at high magnetic field. The observed oscillatory transfer kinetics is taken as a clear indication of a coherent mechanism; level crossing effects have also been demonstrated. The experimental data are in very good agreement with the theoretical model of coherent polarization transfer. The method suggested is also valid for other types of initial polarization in the spin system, most notably, for spin hyperpolarization.

Pravdivtsev, Andrey N.; Yurkovskaya, Alexandra V.; Ivanov, Konstantin L., E-mail: ivanov@tomo.nsc.ru [International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova 2, Novosibirsk 630090 (Russian Federation); Vieth, Hans-Martin [Institut für Experimental Physik, Freie Universität Berlin, Arnimallee 14, Berlin 14195 (Germany)] [Institut für Experimental Physik, Freie Universität Berlin, Arnimallee 14, Berlin 14195 (Germany)

2013-12-28

354

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

E-print Network

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.

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

2014-10-02

355

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

356

Single-Spin Transverse Asymmetry in Neutral Pion Production at PHENIX  

NASA Astrophysics Data System (ADS)

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) began operation as the first polarized proton collider in 2001. From data collected in the 2001-2002 run, the PHENIX experiment has measured the single-spin transverse asymmetry (A_N) for neutral pion production at x_F ˜0 over a transverse momentum range of 1.0 to 5.0 GeV/c from polarized proton-proton interactions at a center of mass energy (?s) of 200 GeV. Interest in these measurements arises from the observation of large ( ˜10-30%) single-spin transverse asymmetries in pp_arrowarrow? X at forward angles by the E704 collaboration at Fermilab (?s = 19.4GeV) and the STAR collaboration at RHIC (?(s) = 200GeV), as well as single-spin, azimuthal asymmetries in semi-inclusive deep-inelastic scattering by the HERMES collaboration at DESY. Such large asymmetries were initially surprising because, at leading-order, pQCD predicts only small effects. Recently it has been argued that these large asymmetries may be produced by initial-state effects (e.g. the Sivers effect), final-state effects (e.g. transversity with the Collins effect), higher-twist contributions, or a combination of the three. In this talk, we will report on the results ofthis measurement.

Aidala, Christine

2004-05-01

357

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

NASA Astrophysics Data System (ADS)

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-) 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- major axis in a straightforward manner.

Le Floch, J.-M.; Bradac, C.; Nand, N.; Castelletto, S.; Tobar, M. E.; Volz, T.

2014-09-01

358

Process Dependent Sivers Function and Implication for Single Spin Asymmetry in Inclusive Hadron Production  

SciTech Connect

We study the single transverse spin asymmetries in the single inclusive particle production within the framework of the generalized parton model (GPM). By carefully analyzing the initial- and final-state interactions, we include the process-dependence of the Sivers functions into the GPM formalism. The modified GPM formalism has a close connection with the collinear twist-3 approach. Within the new formalism, we make predictions for inclusive {pi}{sup 0} and direct photon productions at RHIC energies. We find the predictions are opposite to those in the conventional GPM approach.

Leonard Gamberg, Zhong-Bo Kang

2011-01-01

359

Nuclear magnetic relaxation induced by exchange-mediated orientational randomization: Longitudinal relaxation dispersion for a dipole-coupled spin-1/2 pair  

NASA Astrophysics Data System (ADS)

In complex biological or colloidal samples, magnetic relaxation dispersion (MRD) experiments using the field-cycling technique can characterize molecular motions on time scales ranging from nanoseconds to microseconds, provided that a rigorous theory of nuclear spin relaxation is available. In gels, cross-linked proteins, and biological tissues, where an immobilized macromolecular component coexists with a mobile solvent phase, nuclear spins residing in solvent (or cosolvent) species relax predominantly via exchange-mediated orientational randomization (EMOR) of anisotropic nuclear (electric quadrupole or magnetic dipole) couplings. The physical or chemical exchange processes that dominate the MRD typically occur on a time scale of microseconds or longer, where the conventional perturbation theory of spin relaxation breaks down. There is thus a need for a more general relaxation theory. Such a theory, based on the stochastic Liouville equation (SLE) for the EMOR mechanism, is available for a single quadrupolar spin I = 1. Here, we present the corresponding theory for a dipole-coupled spin-1/2 pair. To our knowledge, this is the first treatment of dipolar MRD outside the motional-narrowing regime. Based on an analytical solution of the spatial part of the SLE, we show how the integral longitudinal relaxation rate can be computed efficiently. Both like and unlike spins, with selective or non-selective excitation, are treated. For the experimentally important dilute regime, where only a small fraction of the spin pairs are immobilized, we obtain simple analytical expressions for the auto-relaxation and cross-relaxation rates which generalize the well-known Solomon equations. These generalized results will be useful in biophysical studies, e.g., of intermittent protein dynamics. In addition, they represent a first step towards a rigorous theory of water 1H relaxation in biological tissues, which is a prerequisite for unravelling the molecular basis of soft-tissue contrast in clinical magnetic resonance imaging.

Chang, Zhiwei; Halle, Bertil

2013-10-01

360

Theoretical study of homonuclear J coupling between quadrupolar spins: Single-crystal, DOR, and J-resolved NMR  

NASA Astrophysics Data System (ADS)

The theory describing homonuclear indirect nuclear spin-spin coupling (J) interactions between pairs of quadrupolar nuclei is outlined and supported by numerical calculations. The expected first-order multiplets for pairs of magnetically equivalent (A2), chemically equivalent (AA?), and non-equivalent (AX) quadrupolar nuclei are given. The various spectral changeovers from one first-order multiplet to another are investigated with numerical simulations using the SIMPSON program and the various thresholds defining each situation are given. The effects of chemical equivalence, as well as quadrupolar coupling, chemical shift differences, and dipolar coupling on double-rotation (DOR) and J-resolved NMR experiments for measuring homonuclear J coupling constants are investigated. The simulated J coupling multiplets under DOR conditions largely resemble the ideal multiplets predicted for single crystals, and a characteristic multiplet is expected for each of the A2, AA?, and AX cases. The simulations demonstrate that it should be straightforward to distinguish between magnetic inequivalence and equivalence using J-resolved NMR, as was speculated previously. Additionally, it is shown that the second-order quadrupolar-dipolar cross-term does not affect the splittings in J-resolved experiments. Overall, the homonuclear J-resolved experiment for half-integer quadrupolar nuclei is demonstrated to be robust with respect to the effects of first- and second-order quadrupolar coupling, dipolar coupling, and chemical shift differences.

Perras, Frédéric A.; Bryce, David L.

2014-05-01

361

Dynamic nuclear polarization and Hanle effect in (In,Ga)As/GaAs quantum dots. Role of nuclear spin fluctuations  

SciTech Connect

The degree of circular polarization of photoluminescence of (In,Ga)As quantum dots as a function of magnetic field applied perpendicular to the optical axis (Hanle effect) is experimentally studied. The measurements have been performed at various regimes of the optical excitation modulation. The analysis of experimental data has been performed in the framework of a vector model of regular nuclear spin polarization and its fluctuations. The analysis allowed us to evaluate the magnitude of nuclear polarization and its dynamics at the experimental conditions used.

Gerlovin, I. Ya. [Spin Optics Laboratory, Saint Petersburg State University, Petrodvorets, 198504 St. Petersburg (Russian Federation); Cherbunin, R. V.; Ignatiev, I. V.; Kuznetsova, M. S.; Verbin, S. Yu. [Spin Optics Laboratory, Saint Petersburg State University, Petrodvorets, 198504 St. Petersburg, Russia and Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund (Germany); Flisinski, K.; Bayer, M. [Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund (Germany); Reuter, D.; Wieck, A. D. [Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Yakovlev, D. R. [Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund, Germany and A. F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation)

2013-12-04

362

Advances and applications of dynamic-angle spinning nuclear magnetic resonance  

SciTech Connect

This dissertation describes nuclear magnetic resonance experiments and theory which have been developed to study quadrupolar nuclei (those nuclei with spin greater than one-half) in the solid state. Primarily, the technique of dynamic-angle spinning (DAS) is extensively reviewed and expanded upon in this thesis. Specifically, the improvement in both the resolution (two-dimensional pure-absorptive phase methods and DAS angle choice) and sensitivity (pulse-sequence development), along with effective spinning speed enhancement (again through choice of DAS conditions or alternative multiple pulse schemes) of dynamic-angle spinning experiment was realized with both theory and experimental examples. The application of DAS to new types of nuclei (specifically the {sup 87}Rb and {sup 85}Rb nuclear spins) and materials (specifically amorphous solids) has also greatly expanded the possibilities of the use of DAS to study a larger range of materials. This dissertation is meant to demonstrate both recent advances and applications of the DAS technique, and by no means represents a comprehensive study of any particular chemical problem.

Baltisberger, J.H.

1993-06-01

363

Spin Dynamics of a Single Mn Ion in a CdTe/(Cd, Mg, Zn)Te Quantum Dot  

SciTech Connect

The spin dynamics of a single Mn ion confined in a CdTe/(Cd, Mg, Zn)Te quantum dot is determined by measurements of photon correlation of photoluminescence. The characteristic time of spin flip is a few nanoseconds and strongly depends on the excitation power.

Goryca, Mateusz; Kossacki, Piotr; Golnik, Andrzej; Kazimierczuk, Tomasz; Nawrocki, Michal [Institute of Experimental Physics, University of Warsaw, Hoza 69, 00-681 Warszawa (Poland); Wojnar, Piotr [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warszawa (Poland)

2010-01-04

364

All-optical NMR in semiconductors provided by resonant cooling of nuclear spins interacting with electrons in the resonant spin amplification regime  

NASA Astrophysics Data System (ADS)

Resonant cooling of different nuclear isotopes manifested in optically induced nuclear magnetic resonances (NMR) is observed in n-doped CdTe/(Cd,Mg)Te and ZnSe/(Zn,Mg)Se quantum wells and for donor-bound electrons in ZnSe:F and GaAs epilayers. By time-resolved Kerr rotation used in the regime of resonant spin amplification, we can expand the range of magnetic fields where the effect can be observed up to nuclear Larmor frequencies of 170 kHz. The mechanism of the resonant cooling of the nuclear spin system is analyzed theoretically. The developed approach allows us to model the resonant spin amplification signals with NMR features.

Zhukov, E. A.; Greilich, A.; Yakovlev, D. R.; Kavokin, K. V.; Yugova, I. A.; Yugov, O. A.; Suter, D.; Karczewski, G.; Wojtowicz, T.; Kossut, J.; Petrov, V. V.; Dolgikh, Yu. K.; Pawlis, A.; Bayer, M.

2014-08-01

365

Shell structure at high spin and the influence on nuclear shapes  

SciTech Connect

Nuclear structure at high spin is influenced by a combination of liquid-drop and shell-structure effects. For N < 86 both contribute towards the occurrence along the yrast line of high-spin oblate aligned-particle configurations. Shell effects are mainly responsible for the prolate deformation of nuclei with N > 90. The competition between oblate and prolate driving effects leads to a prolate-to-oblate shape transition in /sup 154/Dy/sub 88/. The role of rotation-aligned configurations in the shape change is discussed.

Khoo, T.L.; Chowdhury, P.; Ahmad, I.

1982-01-01

366

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

367

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

PubMed Central

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

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

2011-01-01

368

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

SciTech Connect

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.

Choudhary, Shashank, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Tejesh, Chiruvolu Mohan, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Regalla, Srinivasa Prakash, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in; Suresh, Kurra, E-mail: shashankbit08@gmail.com, E-mail: mohantejesh93@gmail.com, E-mail: regalla@hyderabad.bits-pilani.ac.in, E-mail: ksuresh@hyderabad.bits-pilani.ac.in [Department of Mechanical Engineering, BITS-Pilani, Hyderabad Campus, Shamirpet, Hyderabad, 500078, Andhra Pradesh (India)

2013-12-16

369

Nuclear Configurations in the Spin-Orbit Coupling Model. I. Empirical Evidence  

Microsoft Academic Search

An extreme one particle model of the nucleus is proposed. The model is based on the succession of energy levels of a single particle in a potential between that of a three-dimensional harmonic oscillator and a square well. (1) Strong spin orbit coupling leading to inverted doublets is assumed. (2) An even number of identical nucleons are assumed to couple

Maria Goeppert Mayer

1950-01-01

370

Spin  

Microsoft Academic Search

According to quantum mechanics, spin—the intrinsic angular momentum of an electron, nucleus, or elementary particle at rest—is\\u000a a decidedly nonclassical concept. The ? spin statistics theorem of ? quantum statistics distinguishes bosons and fermions\\u000a obeying ? Bose-Einstein statistics or ? Fermi-Dirac statistics, respectively, depending on whether the particle's spin is\\u000a an even or odd multiple of h\\/2, with h =

Klaus Hentschel

371

Spin-polarized density-matrix functional theory of the single-impurity Anderson model  

NASA Astrophysics Data System (ADS)

Lattice density functional theory (LDFT) is used to investigate spin excitations in the single-impurity Anderson model. In this method, the single-particle density matrix ?ij? with respect to the lattice sites replaces the wave function as the basic variable of the many-body problem. A recently developed two-level approximation (TLA) to the interaction-energy functional W[?] is extended to systems having spin-polarized density distributions and bond orders. This allows us to investigate the effect of external magnetic fields and, in particular, the important singlet-triplet gap ?E, which determines the Kondo temperature. Applications to finite Anderson rings and square lattices show that the gap ?E as well as other ground-state and excited-state properties are very accurately reproduced. One concludes that the spin-polarized TLA is reliable in all interaction regimes, from weak to strong correlations, for different hybridization strengths and for all considered impurity valence states. In this way the efficiency of LDFT to account for challenging electron-correlation effects is demonstrated.

Töws, W.; Pastor, G. M.

2012-12-01

372

Preparation of Non-equilibrium Nuclear Spin States in Double Quantum Dots  

E-print Network

We theoretically study the dynamic polarization of lattice nuclear spins in GaAs double quantum dots containing two electrons. In our prior work [Phys. Rev. Lett. 104, 226807 (2010)] we identified three regimes of long-term dynamics, including the build up of a large difference in the Overhauser fields across the dots, the saturation of the nuclear polarization process associated with formation of so-called "dark states," and the elimination of the difference field. In particular, when the dots are different sizes we found that the Overhauser field becomes larger in the smaller dot. Here we present a detailed theoretical analysis of these problems including a model of the polarization dynamics and the development of a new numerical method to efficiently simulate semiclassical central-spin problems. When nuclear spin noise is included, the results agree with our prior work indicating that large difference fields and dark states are stable configurations, while the elimination of the difference field is unstable; however, in the absence of noise we find all three steady states are achieved depending on parameters. These results are in good agreement with dynamic nuclear polarization experiments in double quantum dots.

M. Gullans; J. J. Krich; J. M. Taylor; B. I. Halperin; M. D. Lukin

2014-07-25

373

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Spin Relaxation of Electrons in Single InAs Quantum Dots  

NASA Astrophysics Data System (ADS)

By using polarization-resolved photoluminescence spectra, we study the electron spin relaxation in single InAs quantum dots (QDs) with the configuration of positively charged excitons X+ (one electron, two holes). The spin relaxation rate of the hot electrons increases with the increasing energy of exciting photons. For electrons localized in QDs the spin relaxation is induced by hyperfine interaction with the nuclei. A rapid decrease of polarization degree with increasing temperature suggests that the spin relaxation mechanisms are mainly changed from the hyperfine interaction with nuclei into an electron-hole exchange interaction.

Ma, Shan-Shan; Dou, Xiu-Ming; Chang, Xiu-Ying; Sun, Bao-Quan; Xiong, Yong-Hua; Niu, Zhi-Chuan; Ni, Hai-Qiao

2009-11-01

374

Utilization of site-directed spin labeling and high-resolution heteronuclear nuclear magnetic resonance for global fold determination of large proteins with limited nuclear overhauser effect data.  

PubMed

To test whether distances derived from paramagnetic broadening of (15)N heteronuclear single quantum coherence (HSQC) resonances could be used to determine the global fold of a large, perdeuterated protein, we used site-directed spin-labeling of 5 amino acids on the surface of (15)N-labeled eukaryotic translation initiation factor 4E (eIF4E). eIF4E is a 25 kDa translation initiation protein, whose solution structure was previously solved in a 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate hydrate (CHAPS) micelle of total molecular mass approximately 45-50 kDa. Distance-dependent line broadening consistent with the three-dimensional structure of eIF4E was observed for all spin-label substitutions. The paramagnetic broadening effects (PBEs) were converted into distances for modeling by a simple method comparing peak heights in (15)N-HSQC spectra before and after reduction of the nitroxide spin label with ascorbic acid. The PBEs, in combination with HN-HN nuclear Overhauser effects (NOEs) and chemical shift index (CSI) angle restraints, correctly determined the global fold of eIF4E with a backbone precision of 2.3 A (1.7 A for secondary structure elements). The global fold was not correctly determined with the HN-HN NOEs and CSI angles alone. The combination of PBEs with simulated restraints from another nuclear magnetic resonance (NMR) method for global fold determination of large proteins (methyl-protonated, highly deuterated samples) improved the quality of calculated structures. In addition, the combination of the two methods simulated from a crystal structure of an all alpha-helical protein (40 kDa farnesyl diphoshphate synthase) correctly determined the global fold where neither method individually was successful. These results show the potential feasibility of obtaining medium-resolution structures for proteins in the 40-100 kDa range via NMR. PMID:10820006

Battiste, J L; Wagner, G

2000-05-01

375

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

E-print Network

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.

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

2010-08-18

376

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

NASA Astrophysics Data System (ADS)

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.

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

377

Spin-Lattice Relaxation Times of Single Donors and Donor Clusters in Silicon  

NASA Astrophysics Data System (ADS)

An atomistic method of calculating the spin-lattice relaxation times (T1 ) is presented for donors in silicon nanostructures comprising of millions of atoms. The method takes into account the full band structure of silicon including the spin-orbit interaction. The electron-phonon Hamiltonian, and hence, the deformation potential, is directly evaluated from the strain-dependent tight-binding Hamiltonian. The technique is applied to single donors and donor clusters in silicon, and explains the variation of T1 with the number of donors and electrons, as well as donor locations. Without any adjustable parameters, the relaxation rates in a magnetic field for both systems are found to vary as B5 , in excellent quantitative agreement with experimental measurements. The results also show that by engineering electronic wave functions in nanostructures, T1 times can be varied by orders of magnitude.

Hsueh, Yu-Ling; Büch, Holger; Tan, Yaohua; Wang, Yu; Hollenberg, Lloyd C. L.; Klimeck, Gerhard; Simmons, Michelle Y.; Rahman, Rajib

2014-12-01

378

Spin-lattice relaxation times of single donors and donor clusters in silicon.  

PubMed

An atomistic method of calculating the spin-lattice relaxation times (T?) is presented for donors in silicon nanostructures comprising of millions of atoms. The method takes into account the full band structure of silicon including the spin-orbit interaction. The electron-phonon Hamiltonian, and hence, the deformation potential, is directly evaluated from the strain-dependent tight-binding Hamiltonian. The technique is applied to single donors and donor clusters in silicon, and explains the variation of T? with the number of donors and electrons, as well as donor locations. Without any adjustable parameters, the relaxation rates in a magnetic field for both systems are found to vary as B?, in excellent quantitative agreement with experimental measurements. The results also show that by engineering electronic wave functions in nanostructures, T? times can be varied by orders of magnitude. PMID:25541787

Hsueh, Yu-Ling; Büch, Holger; Tan, Yaohua; Wang, Yu; Hollenberg, Lloyd C L; Klimeck, Gerhard; Simmons, Michelle Y; Rahman, Rajib

2014-12-12

379

Room temperature high-fidelity holonomic single-qubit gate on a solid-state spin  

NASA Astrophysics Data System (ADS)

At its most fundamental level, circuit-based quantum computation relies on the application of controlled phase shift operations on quantum registers. While these operations are generally compromised by noise and imperfections, quantum gates based on geometric phase shifts can provide intrinsically fault-tolerant quantum computing. Here we demonstrate the high-fidelity realization of a recently proposed fast (non-adiabatic) and universal (non-Abelian) holonomic single-qubit gate, using an individual solid-state spin qubit under ambient conditions. This fault-tolerant quantum gate provides an elegant means for achieving the fidelity threshold indispensable for implementing quantum error correction protocols. Since we employ a spin qubit associated with a nitrogen-vacancy colour centre in diamond, this system is based on integrable and scalable hardware exhibiting strong analogy to current silicon technology. This quantum gate realization is a promising step towards viable, fault-tolerant quantum computing under ambient conditions.

Arroyo-Camejo, Silvia; Lazariev, Andrii; Hell, Stefan W.; Balasubramanian, Gopalakrishnan

2014-09-01

380

Room temperature high-fidelity holonomic single-qubit gate on a solid-state spin.  

PubMed

At its most fundamental level, circuit-based quantum computation relies on the application of controlled phase shift operations on quantum registers. While these operations are generally compromised by noise and imperfections, quantum gates based on geometric phase shifts can provide intrinsically fault-tolerant quantum computing. Here we demonstrate the high-fidelity realization of a recently proposed fast (non-adiabatic) and universal (non-Abelian) holonomic single-qubit gate, using an individual solid-state spin qubit under ambient conditions. This fault-tolerant quantum gate provides an elegant means for achieving the fidelity threshold indispensable for implementing quantum error correction protocols. Since we employ a spin qubit associated with a nitrogen-vacancy colour centre in diamond, this system is based on integrable and scalable hardware exhibiting strong analogy to current silicon technology. This quantum gate realization is a promising step towards viable, fault-tolerant quantum computing under ambient conditions. PMID:25216026

Arroyo-Camejo, Silvia; Lazariev, Andrii; Hell, Stefan W; Balasubramanian, Gopalakrishnan

2014-01-01

381

Room temperature high-fidelity holonomic single-qubit gate on a solid-state spin  

PubMed Central

At its most fundamental level, circuit-based quantum computation relies on the application of controlled phase shift operations on quantum registers. While these operations are generally compromised by noise and imperfections, quantum gates based on geometric phase shifts can provide intrinsically fault-tolerant quantum computing. Here we demonstrate the high-fidelity realization of a recently proposed fast (non-adiabatic) and universal (non-Abelian) holonomic single-qubit gate, using an individual solid-state spin qubit under ambient conditions. This fault-tolerant quantum gate provides an elegant means for achieving the fidelity threshold indispensable for implementing quantum error correction protocols. Since we employ a spin qubit associated with a nitrogen-vacancy colour centre in diamond, this system is based on integrable and scalable hardware exhibiting strong analogy to current silicon technology. This quantum gate realization is a promising step towards viable, fault-tolerant quantum computing under ambient conditions. PMID:25216026

Arroyo-Camejo, Silvia; Lazariev, Andrii; Hell, Stefan W.; Balasubramanian, Gopalakrishnan

2014-01-01

382

Transverse single spin and azimuthal asymmetries in hadronic collisions at PHENIX  

NASA Astrophysics Data System (ADS)

Inclusive transverse single spin asymmetries from high energetic polarized proton proton collisions provide insight into the spin-momentum correlations in QCD. Originally expected to be small in collinear perturbative QCD, results from PHENIX and other experiments show significant asymmetries in the forward momentum direction of the polarized proton over a wide range of center-of-mass energies. Several mechanisms have been proposed that attempt to explain these asymmetries, which include initial and final state effects. In order to disentangle these effects, a variety of probes is needed in different kinematic regions. In the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC), we study polarized p+p collisions at center-of-mass energies up to 500 GeV. We will show transverse asymmetries at forward (3.1< |?| <3.8) and central rapidities (|?| <0.35) and discuss their possible implications for intitial and final state effects.

Kleinjan, David

2015-01-01

383

Electron spin resonance of nitrogen-vacancy defects embedded in single nanodiamonds in an ABEL trap.  

PubMed

Room temperature optically detected magnetic resonance of a single quantum object with nanoscale position control is an outstanding challenge in many areas, particularly in the life sciences. We introduce a novel approach to control the nitrogen-vacancy (NV) centers hosted in a single fluorescent nanodiamond (FND) for which an anti-Brownian electrokinetic trap (ABEL) performs the position control and an integrated radiofrequency (RF) circuit provides enhanced magnetic flux density for ensemble spin-state control simultaneously. We demonstrate static magnetic field sensing in platforms compatible with ABEL trap. With the advances in the synthesis and functionalization of stable arbitrarily small FNDs, we foresee the use of our device for the trapping and manipulation of single molecular-sized FNDs in aqueous solution. PMID:25111386

Kayci, Metin; Chang, Huan-Cheng; Radenovic, Aleksandra

2014-09-10

384

All-Optical Sensing of a Single-Molecule Electron Spin  

NASA Astrophysics Data System (ADS)

We demonstrate an all-optical method for magnetic sensing of individual molecules in ambient conditions at room temperature. Our approach is based on shallow nitrogen-vacancy (NV) centers near the surface of a diamond crystal, which we use to detect single paramagnetic molecules covalently attached to the diamond surface. The manipulation and readout of the NV centers is all-optical and provides a sensitive probe of the magnetic field fluctuations stemming from the dynamics of the electronic spins of the attached molecules. As a specific example, we demonstrate detection of a single paramagnetic molecule containing a gadolinium (Gd$^{3+}$) ion. We confirm single-molecule resolution using optical fluorescence and atomic force microscopy to co-localize one NV center and one Gd$^{3+}$-containing molecule. Possible applications include nanoscale and in vivo magnetic spectroscopy and imaging of individual molecules.

Sushkov, A. O.; Chisholm, N.; Lovchinsky, I.; Kubo, M.; Lo, P. K.; Bennett, S. D.; Hunger, D.; Akimov, A.; Walsworth, R. L.; Park, H.; Lukin, M. D.

2014-11-01

385

High-pressure magic angle spinning nuclear magnetic resonance  

NASA Astrophysics Data System (ADS)

A high-pressure magic angle spinning (MAS) NMR capability, consisting of a reusable high-pressure MAS rotor, a high-pressure rotor loading/reaction chamber for in situ sealing and re-opening of the high-pressure MAS rotor, and a MAS probe with a localized RF coil for background signal suppression, is reported. The unusual technical challenges associated with development of a reusable high-pressure MAS rotor are addressed in part by modifying standard ceramics for the rotor sleeve by abrading the internal surface at both ends of the cylinder. In this way, not only is the advantage of ceramic cylinders for withstanding very high-pressure utilized, but also plastic bushings can be glued tightly in place so that other removable plastic sealing mechanisms/components and O-rings can be mounted to create the desired high-pressure seal. Using this strategy, sealed internal pressures exceeding 150 bars have been achieved and sustained under ambient external pressure with minimal loss of pressure for 72 h. As an application example, in situ13C MAS NMR studies of mineral carbonation reaction intermediates and final products of forsterite (Mg 2SiO 4) reacted with supercritical CO 2 and H 2O at 150 bar and 50 °C are reported, with relevance to geological sequestration of carbon dioxide.

Hoyt, David W.; Turcu, Romulus V. F.; Sears, Jesse A.; Rosso, Kevin M.; Burton, Sarah D.; Felmy, Andrew R.; Hu, Jian Zhi

2011-10-01

386

? nuclear magnetic resonance and electron spin resonance of amorphous hydrogenated carbon  

NASA Astrophysics Data System (ADS)

The temperature dependences of the 0953-8984/10/30/019/img9 and 0953-8984/10/30/019/img10 magnetization recovery and spin-lattice relaxation times as well as the 0953-8984/10/30/019/img9 NMR spectra have been studied between 300 K and 4 K. The observed short and nearly temperature independent proton and 0953-8984/10/30/019/img9 spin-lattice relaxation times demonstrate that the dominant spin-lattice relaxation mechanism is spin diffusion to paramagnetic impurities. The fact that the magnetization recovery curves clearly deviate from the single-exponential form expected for the case of spin diffusion and randomly distributed paramagnetic centres demonstrates that the paramagnetic centres aggregate in clusters. Superparamagnetic freezing effects expected for such an inhomogeneous distribution are indeed seen below 50 K in the temperature dependence of the electron spin-resonance (ESR) intensity, the 0953-8984/10/30/019/img9 NMR spectra and the SQUID magnetization measurements which show a distinct magnetic hysteresis loop.

Blinc, R.; Arcon, D.; Cevc, P.; Pocsik, I.; Koos, M.; Trontelj, Z.; Jaglicic, Z.

1998-08-01

387

Spin-dipole strength functions of 4He with realistic nuclear forces  

NASA Astrophysics Data System (ADS)

Both isoscalar and isovector spin-dipole excitations of 4He are studied using realistic nuclear forces in the complex scaling method. The ground state of 4He and discretized continuum states with J?=0-,1-,2- for A=4 nuclei are described in explicitly correlated Gaussians reinforced with global vectors for angular motion. Two- and three-body decay channels are specifically treated to take into account final state interactions. The observed resonance energies and widths of the negative-parity levels are all in fair agreement with those calculated from both the spin-dipole and electric-dipole strength functions as well as the energy eigenvalues of the complex scaled Hamiltonian. Spin-dipole sum rules, both non-energy-weighted and energy-weighted, are discussed in relation to tensor correlations in the ground state of 4He.

Horiuchi, W.; Suzuki, Y.

2013-03-01

388

Optical and Nuclear Spin Spectroscopy in PRASEODYMIUM(3+):LANTHANUM Fluoride by Optical Pumping  

NASA Astrophysics Data System (ADS)

A Stark Modulated Optical Pumping (SMOP) technique was used as a sensitive probe of optical hole-burning to study the effects of nuclear spin interactions in Pr ^{3+}:LaF_3. The results of two experiments are reported. In the first experiment, the SMOP technique is applied for optical detection of the NQR spectrum of the Pr^{3+} optical ground state. Frequency and linewidth variations of the Pr ^{3+} ground state hyperfine levels for different positions within the main ^3 H_4(Gamma1) -^1D_2(Gamma 1) inhomogeneous optical line and satellite transitions of Pr^{3+}:LaF _3 are observed. A linear increase in the broadening of the Pr^{3+} hyperfine transitions, without a shift of central frequency, is measured as the laser is tuned toward the wings of the inhomogeneous optical transition. The linear variation is attributed to electric quadrupole broadening caused by changes in local density of point defects across the Stark broadened optical transition. The optically detected NQR spectra of the satellite transitions associated with Pr ion pairs are shifted in frequency, and for most satellites are narrower in width than the NQR spectra found in the wings of the main inhomogeneous optical line. In the second experiment, direct evidence for the presence of a spin diffusion barrier or "frozen core" in Pr^{3+}:LaF _3 is observed by examining the cross relaxation between the Pr and F nuclei in a magnetic field chosen so that a pair of the optical ground state Pr^ {3+} hyperfine energy levels matches the F splitting or a multiple of the F splitting. This level crossing condition allows resonant flip-flop interactions with the nearest neighbor frozen core fluorine spins to re-populate Pr^{3+} hyperfine levels emptied by laser hole-burning, and is detected as enhanced absorption of the laser beam. The coupling of core fluorine spins to bulk fluorine spins during Pr-F cross-relaxation is measured by NMR of the bulk fluorine spin magnetization. The rate of cross relaxation between the Pr spins and the bulk F spins measured in this way is at least three to four orders of magnitude slower than that expected in the absence of a spin diffusion barrier. This reduction of coupling indicates nearly complete de-tuning of the frozen core F spins immediately surrounding the Pr^{3+} ion, cutting off resonant coupling with the bulk F spins.

Wald, Lawrence Leroy

389

Single-spin microscope with sub-nanoscale resolution based on optically detected magnetic resonance  

SciTech Connect

Invention of scanning tunneling microscope (STM) and atomic force microscope (AFM) initiated a new era of material science and technology characterized by 2-D imaging with atomic resolution and manipulation of individual atoms. However, for further progress in material science, and in particular in structural biology, 3-D imaging with sub-nanometer resolution is very desirable. Currently the most promising technique for 3-D imaging is magnetic resonance force microscopy (MRFM), which senses individual electron spins [1,2] with nanoscale resolution and can detect collective magnetization of about 100 nuclear spins [3]. The highest sensitivity demonstrated by MRFM is based on a time modulation technique called the oscillating cantilever-driven adiabatic reversals (OSCAAR) which requires a long phase relaxation time T 2 of measured spins, which usually corresponds to rather low temperature. For example, a temperature of 300 mK was used in the case of 3D imaging of the tobacco mosaic virus [3]. This limitation is incompatible with the room-temperature operation needed for the study of biological systems under physiological conditions.

Berman, Gennady P [Los Alamos National Laboratory; Chernobrod, Boris [Los Alamos National Laboratory

2009-01-01

390

1H nuclear spin relaxation of liquid water from molecular dynamics simulations.  

PubMed

We have investigated the nuclear spin relaxation properties of (1)H in liquid water with the help of molecular dynamics simulations. We have computed the (1)H nuclear spin relaxation times T1 and T2 and determined the contribution of the different interactions to the relaxation at different temperatures and for different classical water models (SPC/E, TIP3P, TIP4P, and TIP4P/2005). Among the water models considered, the TIP4P/2005 model exhibits the best agreement with the experiment. The same analysis was performed with Car-Parrinello ab initio molecular dynamics simulations of bulk water at T = 330 K, which provided results close to the experimental values at room temperature. To complete the study, we have successfully accounted for the temperature-dependence of T1 and T2 in terms of a simplified model, which considers the reorientation in finite angle jumps and the diffusive translation of water molecules. PMID:25584483

Calero, C; Martí, J; Guàrdia, E

2015-02-01

391

Nuclear Spins as Quantum Testbeds: Singlet States, Quantum Correlations, and Delayed-choice Experiments  

E-print Network

Nuclear Magnetic Resonance (NMR) forms a natural test-bed to perform quantum information processing (QIP) and has so far proven to be one of the most successful quantum information processors. The nuclear spins in a molecule treated as quantum bits or qubits which are the basic building blocks of a quantum computer. The development of NMR over half a century puts it in a platform where we can utilize its excellent control techniques over an ensemble of spin systems and perform quantum computation in a highly controlled way. Apart from a successful quantum information processor, NMR is also a highly powerful quantum platform where many of the potentially challenging quantum mechanical experiments can be performed.

Soumya Singha Roy

2012-10-28

392

The Low-Temperature Nuclear Spin Equilibrium of H_3^+ in Collisions with H_2  

NASA Astrophysics Data System (ADS)

Observations of H_3^+ in diffuse molecular clouds have revealed that the ratio of its ortho and para nuclear spin modifications are not in thermodynamic equilibrium with the environment. This discrepancy could be explained if the reaction H_3^+ + H_2 to H_2 + H_3^+, which interconverts the nuclear spin modifications of H_3^+, has a nonthermal outcome at low temperatures, possibly arising from nuclear spin selection rules on systems of identical fermions. While the nuclear spin dependence of this reaction has previously been investigated experimentally, the prior measurements were limited to temperatures above ˜130 K, well above the 50-70 K typical of diffuse molecular clouds. To investigate whether the outcome of the H_3^+ + H_2 reaction is nonthermal, H_3^+ ions were allowed to interact with H_2 in the temperature-controlled environment of a 22-pole radiofrequency ion trap, and the relative abundances of ortho- and para-H_3^+ at steady state were measured using action spectroscopy. By carefully controlling the ortho:para ratio of the H_2 samples in conjunction with the ion trap temperature, the outcome of the reaction was observed to be close to thermodynamic equilibrium over the temperature range of 45-100 K. Thus, the nonequilibrium ortho:para ratio of H_3^+ observed in diffuse molecular clouds does not arise from a nonthermal outcome of the H_3^+ + H_2 reaction at low temperature. This implies that the origin of the discrepancy lies in the respective formation and destruction mechanisms of H_3^+.

Grussie, Florian; Berg, Max H.; Wolf, Andreas; Kreckel, Holger; Crabtree, Kyle N.; McCall, Benjamin J.; Gartner, Sabrina; Schlemmer, Stephan

2013-06-01

393

Nuclear Ground State Spins of the Francium Isotopes 208-213, 220-222Fr  

Microsoft Academic Search

The nuclear ground state spins of some francium isotopes have been measured using on-line atomic-beam magnetic resonance techniques. The following results have been obtained: 208Fr I = 7, 209Fr I = 9\\/2, 210Fr I = 6, 211Fr I = 9\\/2, 212Fr I = 5, 213Fr I = 9\\/2, 220Fr I = 1, 221Fr I = 5\\/2 and 222Fr I =

C. Ekström; S. Ingelman; G. Wannberg; M. Skarestad

1978-01-01

394

Discrimination of nuclear spin isomers exploiting the excited state dynamics of a quinodimethane derivative  

SciTech Connect

Despite the concept of nuclear spin isomers (NSIs) exists since the early days of quantum mechanics, only few approaches have been suggested to separate different NSIs. Here, a method is proposed to discriminate different NSIs of a quinodimethane derivative using its electronic excited state dynamics. After electronic excitation by a laser field with femtosecond time duration, a difference in the behavior of several quantum mechanical operators can be observed. A pump-probe experimental approach for separating these different NSIs is then proposed.

Obaid, Rana [Institut für Theoretische Chemie, Universität Wien, Währinger Str. 17, 1090 Wien (Austria); Faculty of Pharmacy, Al-Quds University, Abu Dis, Palestine (Country Unknown); Kinzel, Daniel; Oppel, Markus, E-mail: markus.oppel@univie.ac.at; González, Leticia [Institut für Theoretische Chemie, Universität Wien, Währinger Str. 17, 1090 Wien (Austria)

2014-10-28

395

Relativistic theory of nuclear spin-rotation tensor with kinetically balanced rotational London orbitals  

SciTech Connect

Both kinetically balanced (KB) and kinetically unbalanced (KU) rotational London orbitals (RLO) are proposed to resolve the slow basis set convergence in relativistic calculations of nuclear spin-rotation (NSR) coupling tensors of molecules containing heavy elements [Y. Xiao and W. Liu, J. Chem. Phys. 138, 134104 (2013)]. While they perform rather similarly, the KB-RLO Ansatz is clearly preferred as it ensures the correct nonrelativistic limit even with a finite basis. Moreover, it gives rise to the same “direct relativistic mapping” between nuclear magnetic resonance shielding and NSR coupling tensors as that without using the London orbitals [Y. Xiao, Y. Zhang, and W. Liu, J. Chem. Theory Comput. 10, 600 (2014)].

Xiao, Yunlong; Zhang, Yong; Liu, Wenjian, E-mail: liuwjbdf@gmail.com [Beijing National Laboratory for Molecular Sciences, Institute of Theoretical and Computational Chemistry, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, and Center for Computational Science and Engineering, Peking University, Beijing 100871 (China)

2014-10-28

396

Relativistic theory of nuclear spin-rotation tensor with kinetically balanced rotational London orbitals  

NASA Astrophysics Data System (ADS)

Both kinetically balanced (KB) and kinetically unbalanced (KU) rotational London orbitals (RLO) are proposed to resolve the slow basis set convergence in relativistic calculations of nuclear spin-rotation (NSR) coupling tensors of molecules containing heavy elements [Y. Xiao and W. Liu, J. Chem. Phys. 138, 134104 (2013)]. While they perform rather similarly, the KB-RLO Ansatz is clearly preferred as it ensures the correct nonrelativistic limit even with a finite basis. Moreover, it gives rise to the same "direct relativistic mapping" between nuclear magnetic resonance shielding and NSR coupling tensors as that without using the London orbitals [Y. Xiao, Y. Zhang, and W. Liu, J. Chem. Theory Comput. 10, 600 (2014)].

Xiao, Yunlong; Zhang, Yong; Liu, Wenjian

2014-10-01

397

Nuclear tetrahedral states and high-spin states studied using quantum number projection method  

E-print Network

We have recently developed an efficient method of performing the full quantum number projection from the most general mean-field (HFB type) wave functions including the angular momentum, parity as well as the proton and neutron particle numbers. With this method, we have been investigating several nuclear structure mechanisms. In this report, we discuss the obtained quantum rotational spectra of the tetrahedral nuclear states formulating certain experimentally verifiable criteria, of the high-spin states, focussing on the wobbling- and chiral-bands, and of the drip-line nuclei as illustrative examples.

S. Tagami; M. Shimada; Y. Fujioka; Y. R. Shimizu; J. Dudek

2014-04-21

398

Ultrafast single electron spin manipulation in 2D semiconductor quantum dots with optimally controlled time-dependent electric fields through spin-orbit coupling  

NASA Astrophysics Data System (ADS)

We have studied theoretically the possibility of ultra-fast manipulation of a single electron spin in 2D semiconductor quantum dots, by means of high-frequency time-dependent electric fields. The electron spin degree of freedom is excited through spin-orbit coupling, and the procedure may be enhanced by the presence of a static magnetic field. We use quantum optimal control theory to tailor the temporal profile of the electric field in order to achieve the most effective manipulation. The scheme predicts significant control over spin operations in times of the order of picoseconds - an ultrafast time scale that permits to avoid the effects of decoherence if this scheme is to be used as a tool for quantum information processing.

Budagosky Marcilla, Jorge A.; Castro, Alberto

2015-01-01

399

Deep Inelastic Scattering of Polarized Electrons off Polarized $^3$HE: Nuclear Effects and the Neutron Spin Structure Function  

E-print Network

Nuclear effects in Deep Inelastic Scattering of polarized electrons off polarized $^3$He are analyzed in terms of a spin dependent spectral function taking into account $S'$ and $D$ waves in $^3$He, as well as Fermi motion and binding effects. A simple and reliable equation relating the neutron and $^3$He spin structure functions is proposed.

C. Ciofi degli Atti; E. Pace; G. Salme`; S. Scopetta

1993-10-22

400

Nuclear structure aspects of spin-independent WIMP scattering off xenon  

E-print Network

We study the structure factors for spin-independent WIMP scattering off xenon based on state-of-the-art large-scale shell-model calculations, which are shown to yield a good spectroscopic description of all experimentally relevant isotopes. Our results are based on the leading scalar one-body currents only. At this level and for the momentum transfers relevant to direct dark matter detection, the structure factors are in very good agreement with the phenomenological Helm form factors used to give experimental limits for WIMP-nucleon cross sections. In contrast to spin-dependent WIMP scattering, the spin-independent channel, at the one-body level, is less sensitive to nuclear structure details. In addition, we explicitly show that the structure factors for inelastic scattering are suppressed by ~ 10^{-4} compared to the coherent elastic scattering response. This implies that the detection of inelastic scattering will be able to discriminate clearly between spin-independent and spin-dependent scattering. Finall...

Vietze, L; Menéndez, J; Haxton, W C; Schwenk, A

2014-01-01

401

Nuclear structure aspects of spin-independent WIMP scattering off xenon  

E-print Network

We study the structure factors for spin-independent WIMP scattering off xenon based on state-of-the-art large-scale shell-model calculations, which are shown to yield a good spectroscopic description of all experimentally relevant isotopes. Our results are based on the leading scalar one-body currents only. At this level and for the momentum transfers relevant to direct dark matter detection, the structure factors are in very good agreement with the phenomenological Helm form factors used to give experimental limits for WIMP-nucleon cross sections. In contrast to spin-dependent WIMP scattering, the spin-independent channel, at the one-body level, is less sensitive to nuclear structure details. In addition, we explicitly show that the structure factors for inelastic scattering are suppressed by ~ 10^{-4} compared to the coherent elastic scattering response. This implies that the detection of inelastic scattering will be able to discriminate clearly between spin-independent and spin-dependent scattering. Finally, we provide fits for all calculated structure factors.

L. Vietze; P. Klos; J. Menéndez; W. C. Haxton; A. Schwenk

2015-02-19

402

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

PubMed

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

Zhang, Xing; Herbert, John M

2014-08-14

403

PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP ENTITLED ''SINGLE SPIN ASYMMETRIES'' (VOLUME 75)  

SciTech Connect

Single-transverse spin asymmetries (SSA) in strong interactions have a long history, starting from the 1970s and 1980s when surprisingly large single-transverse spin asymmetries were observed in p+p {yields} {pi}X and pp {yields} {Lambda} + X, where really none were expected. They have again attracted much interest in recent years from both experimental and theoretical sides. In particular, first measurements by the STAR, PHENIX, and BRAHMS collaborations at RHIC have now become available which again reveal large single transverse spin asymmetries for hadron production in polarized proton proton scattering. This extends the SSA observations from the fixed target energy range to the collider regime. Meanwhile, experimental studies in Deep Inelastic Scattering by the HERMES collaboration at DESY, SMC at CERN, and CLAS at JLab also show a remarkably large SSA in semi-inclusive hadron production, {gamma}*p {yields} {pi}X, when the proton is transversely polarized. On the theoretical side, there are several approaches to understanding SSA within Quantum Chromodynamics (QCD). For example, to explain the large SSAs for hadron production in hadron collisions, a mechanism that takes into account the contribution from quark-gluon-quark correlations (twist-3) in the nucleon was proposed. On the other hand, possible origins of SSA in DIS and hadronic scattering were also found in leading-twist transverse momentum dependent parton distributions. Current theoretical efforts aim at a better conceptual understanding of these two types of mechanisms, and of their connections. We were very happy at this timely date to bring together the theorists and experimentalists of this field to review and discuss the current theoretical status and the latest experimental results. The whole workshop contained 25 formal talks, both experiment (15) and theory (10), and a few informal talks and many fruitful discussions. The topics covered all the relevant SSA observables, including in Deep Inelastic Scattering, the Drell-Yan process, and in inclusive hadron production and dijet correlations at hadron colliders. There were not only discussions on possible interpretations of the existing SSA data, but also on the future observables for the ongoing experiments as well as for planned experiments (such as RHIC II and eRHIC). On the theory side, the talks ranged from overviews and descriptions of the fundamental aspects of SSAs, to presentations of detailed phenomenological studies. All of the talks attracted much interest and initiated active discussions. Directions for future measurements were pointed out, in particular for studies at RHIC. Also, significant theoretical advances were made that may tie together some of the currently proposed mechanisms for single-spin asymmetries. This was a very successful workshop. It stimulated many discussions and new collaborations.

YUAN, F.; VOGELSANG, W.

2005-06-01

404

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

NASA Astrophysics Data System (ADS)

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.

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

405

Do we understand the single-spin asymmetry for ? 0 inclusive production in pp collisions?  

NASA Astrophysics Data System (ADS)

The cross section data for ?^0 inclusive production in pp collisions is considered in a rather broad kinematic region in energy sqrt{s}, Feynman variable x F and transverse momentum p T. The analysis of these data is done in the perturbative QCD framework at the next-to-leading order. We find that they cannot be correctly described in the entire kinematic domain and this leads us to conclude that the single-spin asymmetry, A N for this process, observed several years ago at FNAL by the experiment E704 and the recent result obtained at BNL-RHIC by STAR, are two different phenomena.

Bourrely, C.; Soffer, J.

2004-08-01

406

Spin projection of single-determinant wavefunctions. [application to hydrocarbon radicals and ions  

NASA Technical Reports Server (NTRS)

The components of the one- and two-particle density matrices resulting from spin projection of a single-determinant wave function are rederived by the method of expansion in terms of the natural orbitals of charge density, and the results are found to diverge from those given by Harriman and Sando for the two-particle case. The theory is generalized to include molecules with unequal numbers of electrons and basis orbitals and is applied to a number of organic molecules and ions. The correctness and internal consistency of the results argue in favor of the modification described.

Phillips, D. H.; Schug, J. C.

1974-01-01

407

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

NASA Astrophysics Data System (ADS)

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 color center in diamond. We incorporate multipulse 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.

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

2013-12-01

408

Evolution of twist-3 multi-parton correlation functions relevant to single transverse-spin asymmetry  

E-print Network

We constructed two sets of twist-3 correlation functions that are responsible for generating the novel single transverse-spin asymmetry in the QCD collinear factorization approach. We derive evolution equations for these universal three-parton correlation functions. We calculate evolution kernels relevant to the gluonic pole contributions to the asymmetry at the order of $\\alpha_s$. We find that all evolution kernels are infrared safe as they should be and have a lot in common to the DGLAP evolution kernels of unpolarized parton distributions. By solving the evolution equations, we explicitly demonstrate the factorization scale dependence of these twist-3 correlation functions.

Zhong-Bo Kang; Jian-Wei Qiu

2008-12-03

409

Period Halving in a Single-Mode Datta-Das Spin Field Effect Transistor  

NASA Astrophysics Data System (ADS)

We study a nonballistic single-mode Datta-Das spin field effect transistor (SFET) subject to an external magnetic field parallel to the effective Rashba field. We map the SFET to an effective Aharonov-Bohm interferometer (ABI) and use this mapping to demonstrate that when the magnetic field is sufficiently strong, the Rashba-interaction-induced oscillation period of its conductance at sufficiently high temperature becomes a half of its zero temperature value while the temperature-induced period halving does not occur when the magnetic field is sufficiently weak.

Lee, Hyun-Woo; ?ali?kan, S.; Park, Hyowon

2006-09-01

410

Single-spin asymmetries in electroproduction of pions on the longitudinally polarized nucleon targets  

NASA Astrophysics Data System (ADS)

We study the single-spin asymmetries of pions produced in semi-inclusive deep-inelastic scattering on the longitudinally polarized nucleon targets. We particularly consider the effects of the twist-3 transverse-momentum dependent distribution functions fL? and hL to the asymmetry. We calculate the asymmetric moment AULsin?h for ?+, ?-, and ?0 produced off the proton target at HERMES and compare the results with the HERMES data. We also present the prediction of the same asymmetries for different pions at the kinematics of CLAS 5.5 GeV on a proton target, as well as at COMPASS on a deuteron target.

Lu, Zhun

2014-07-01

411

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

E-print Network

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.

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

2014-07-02

412

Exactly solvable spin dynamics of an electron coupled to a large number of nuclei; the electron-nuclear spin echo in a quantum dot  

SciTech Connect

The model used to describe the spin dynamics in quantum dots after optical excitation is considered. Problems of the electron-spin polarization decay and the dependence of the steady-state polarization on magnetic field are solved on the basis of exact diagonalization of the model Hamiltonian. An important role of the nuclear state is shown and methods of its calculation for different regimes of optical excitation are proposed. The effect of spin echo generation after application of a {pi} pulse of a magnetic field is predicted for the system under consideration.

Kozlov, G. G. [St. Petersburg State University, Institute of Physics (Russian Federation)], E-mail: gkozlov@photonics.phys.spbu.ru

2007-10-15

413

CdSe/ZnSe quantum dot with a single Mn2+ ion—A new system for a single spin manipulation  

NASA Astrophysics Data System (ADS)

We present a magneto-optical study of individual self-assembled CdSe/ZnSe quantum dots doped with single Mn2+ ions. Properties of the studied dots are analyzed analogously to more explored system of Mn-doped CdTe/ZnTe dots. Characteristic sixfold splitting of the neutral exciton emission line as well as its evolution in the magnetic field are described using a spin Hamiltonian model. Dynamics of both exciton recombination and Mn2+ spin relaxation are extracted from a series of time-resolved experiments. Presence of a single dopant is shown not to affect the average excitonic lifetime measured for a number of nonmagnetic and Mn-doped dots. On the other hand, non-resonant pumping is demonstrated to depolarize the Mn2+ spin in a quantum dot placed in external magnetic field. This effect is utilized to determine the ion spin relaxation time in the dark.

Smole?ski, T.

2015-03-01

414

Single-photon-level optical storage in a solid-state spin-wave memory  

NASA Astrophysics Data System (ADS)

A long-lived quantum memory is a firm requirement for implementing a quantum repeater scheme. Recent progress in solid-state rare-earth-ion-doped systems justifies their status as very strong candidates for such systems. Nonetheless an optical memory based on spin-wave storage at the single-photon level has not been shown in such a system to date, which is crucial for achieving the long storage times required for quantum repeaters. In this paper we show that it is possible to execute a complete atomic frequency comb (AFC) scheme, including spin-wave storage, with weak coherent pulses of n¯=2.5±0.6 photons per pulse. We discuss in detail the experimental steps required to obtain this result and demonstrate the coherence of a stored time-bin pulse. We show a noise level of (7.1±2.3)×10-3 photons per mode during storage, and this relatively low noise level paves the way for future quantum optics experiments using spin waves in rare-earth-doped crystals.

Timoney, N.; Usmani, I.; Jobez, P.; Afzelius, M.; Gisin, N.

2013-08-01

415

Teleportation of Electronic Many-Qubit States Encoded in the Electron Spin of Quantum Dots via Single Photons  

E-print Network

Single Photons Michael N. Leuenberger and Michael E. Flatte´ Department of Physics and Astronomy and OSTC propose a teleportation scheme that relies only on single-photon measurements and Faraday rotation. The interaction between a photon and the two electron spins, via Faraday rotation in micro- cavities, establishes

Flatte, Michael E.

416

Nuclear spin dependence of hydrogenic plasmas in the laboratory and the diffuse interstellar medium  

NASA Astrophysics Data System (ADS)

Observations of diffuse molecular clouds have shown that the excitation temperature T(H_3^+) derived from the (J,K) = (1,0) (ortho) and (1,1) (para) rotational levels of H_3^+ does not necessarily agree with the kinetic temperature (T01) inferred from UV measurements of H_2. In four of the five diffuse molecular cloud sight lines for which both H_3^+ and H_2 observations are available, T(H_3^+) is lower than T01 by 30 K. The reaction H_3^+ + H_2 ? H_2 + H_3^+ is expected to thermalize the H_3^+ nuclear spin distribution, but the interplay of nuclear spin selection rules and energetic restrictions at the low temperatures of the diffuse interstellar medium may prevent full thermalization at steady state. Alternatively, the nonthermal distribution could arise if H_3^+ does not experience a sufficient number of thermalizing collisions with H_2 during its lifetime. We have studied the nuclear spin dependence of the reaction of H_3^+ with H_2 in the laboratory by measuring the ortho:para ratio of H_3^+ formed in plasmas of varying ortho:para H_2 ratios. This study was performed in a hollow cathode cell which enabled the first measurements of this reaction at low temperature (130 K). From these measurements, we derived the ratio of the ``proton hop'' and ``hydrogen exchange'' rate coefficients as a function of temperature. The ratio, ?, was found to decrease with temperature, already reaching the statistical limit of 0.5 at a temperature of 130 K. Knowledge of ? enables modeling of the ortho:para ratio of H_3^+ in diffuse molecular clouds. We have modeled the nuclear spin dependence of the formation, thermalization, and destruction processes of H_3^+, and found that the nonthermal distribution is not caused by nuclear spin selection rules or energetic restrictions in the H_3^+ + H_2 reaction. Rather, it is likely caused by incomplete thermalization prior to H_3^+ destruction via electron dissociative recombination.

Crabtree, K. N.; Indriolo, N.; Kreckel, H.; Kauffman, C. A.; Tom, B. A.; Becka, E.; McGuire, B. A.; McCall, B. J.

2011-05-01

417

Nuclear Spin Dependence of Hydrogenic Plasmas in the Laboratory and the Diffuse Interstellar Medium  

NASA Astrophysics Data System (ADS)

Observations of diffuse molecular clouds have shown that the excitation temperature T(H3+) derived from the (J,K) = (1,0) (ortho) and (1,1) (para) rotational levels of H3+ does not necessarily agree with the kinetic temperature (T01) inferred from UV measurements of H2. In four of the five diffuse molecular cloud sight lines for which both H3+ and H2 observations are available, T(H3+) is lower than T01 by 30 K. The reaction H3+ + H2 ? H2 + H3+ is expected to thermalize the H3+ nuclear spin distribution, but the interplay of nuclear spin selection rules and energetic restrictions at the low temperatures of the diffuse interstellar medium may prevent full thermalization at steady state. Alternatively, the nonthermal distribution could arise if H3+ does not experience a sufficient number of thermalizing collisions with H2 during its lifetime. We have studied the nuclear spin dependence of the reaction of H3+ with H2 in the laboratory by measuring the ortho:para ratio of H3+ formed in plasmas of varying ortho:para H2 ratios. This study was performed in a hollow cathode cell which enabled the first measurements of this reaction at low temperature (130 K). From these measurements, we derived the ratio of the "proton hop" and "hydrogen exchange" rate coefficients as a function of temperature. The ratio, ?, was found to decrease with temperature, already reaching the statistical limit of 0.5 at a temperature of 130 K. Knowledge of ? enables modeling of the ortho:para ratio of H3+ in diffuse molecular clouds. We have modeled the nuclear spin dependence of the formation, thermalization, and destruction processes of H3+, and found that the nonthermal distribution is not caused by nuclear spin selection rules or energetic restrictions in the H3+ + H2 reaction. Rather, it is likely caused by incomplete thermalization prior to H3+ destruction via electron dissociative recombination.

Crabtree, Kyle N.; Indriolo, Nick; Kreckel, Holger; Kauffman, Carrie A.; Tom, Brian A.; Beçka, Eftalda; McGuire, Brett A.; McCall, Benjamin J.

2011-10-01

418

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

NASA Astrophysics Data System (ADS)

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.

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

419

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

PubMed

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. PMID:24515020

Wei, Hai-Rui; Deng, Fu-Guo

2014-01-13

420

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

421

Temperature induced Spin Switching in SmFeO3 Single Crystal  

PubMed Central

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

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

2014-01-01

422

Increasing Quantum Dot Electron Spin Coherence with Persistent Spin Narrowing  

Microsoft Academic Search

We demonstrate reproducible initialization of the Overhauser field in a single InAs self-assembled quantum dot using the hole assisted nuclear feedback mechanism. This fixes the mean the Overhauser field to a value determined by two pump lasers and dramatically reduces the statistical broadening of the electron spin resonance arising from averaging over the nuclear spin ensemble, (1\\/T2*). By initializing for

Bo Sun; Colin Chow; Allan Bracker; Daniel Gammon; Lu Sham; Duncan Steel

2011-01-01

423

Nuclear Magnetic Spin-Noise and Unusual Relaxation of Oxygen-17 in Water  

NASA Astrophysics Data System (ADS)

Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) have evolved into widely used techniques, providing diagnostic power in medicine and material sciences due to their high precision and non-invasive nature. Due to the small population differences between spin energy states, a significant sensitivity problem for NMR arises. The low sensitivity of NMR is probably its greatest limitation for applications to biological systems. An alternative probe tuning strategy based on the spin-noise response for application in standard one-dimensional and common high-resolution multidimensional standard biomolecular NMR experiments has shown an increase of up to 50% signal-to-noise (SNR) in one-dimensional NMR experiments and an increase of up to 22% in multi-dimensional ones. The method requires the adjustment of the optimal tuning condition, which may be offset by several hundreds kHz from the conventional tuning settings using the noise response of the water protons as an indicator. This work is described in the first part of the thesis (chapters 2--3). The second part (Chapter 4) of the thesis deals with anomalous oxygen-17 NMR relaxation behavior in water. Oxygen-17 (17O), which has spin of 5/2 and a natural abundance of 0.0373% possesses an electric quadrupole moment. Spin-lattice and spin-spin relaxation occur by the quadrupole interaction, while the J-coupling to 1H spins and exchange are deciding factors. T1 and T2 of 17O in water have been previously measured over a large range of temperatures. The spin-spin relaxation times of 17O as a function of temperature show an anomalous behaviour, expressed by a local maximum at the temperature of maximum density (TMD) of water. It is shown that the same anomalous behaviour shifts to the respective temperatures of maximum density for H2O/D2O solutions with different compositions and salt concentrations. This phenomenon can be correlated to the pH dependency of T2 of 17O in water, and water proton exchange rates at low temperatures that are close to TMD. The investigation of these effects forms the second topic in my thesis. In Chapter 1, some concepts of NMR are introduced as a background to the research work presented. In addition, quadrupolar dynamics of spin-5/2 nuclei is presented to provide the theoretical basis to understand the underlying concepts in Chapter 4. Chapters 2,3 are dedicated to the spin-noise phenomenon and its applications in enhancing SNR, which are based on recent articles, which I authored and co-authored [1, 2]. Chapter 4 is dedicated to research work that centers on the unusual spin-spin relaxation of 17O in water around the TMD. [1] E. Bendet-Taicher, N. Muller, A. Jerschow, Dependence of NMR noise line shapes on tuning, matching, and transmission line properties, Concepts Magn. Reson., 44 (2014) 1--11. [2] M. Nausner, M. Goger, E. Bendet-Taicher, J. Schlagnitweit, A. Jerschow, N. Muller, Signal enhancement in protein NMR using the spin-noise tuning optimum, J Biomol Nmr, 48 (2010) 157--167.

Bendet-Taicher, Eli

424

Rotor design for high pressure magic angle spinning nuclear magnetic resonance  

NASA Astrophysics Data System (ADS)

High pressure magic angle spinning (MAS) nuclear magnetic resonance (NMR) with a sample spinning rate exceeding 2.1 kHz and pressure greater than 165 bar has never been realized. In this work, a new sample cell design is reported, suitable for constructing cells of different sizes. Using a 7.5 mm high pressure MAS rotor as an example, internal pressure as high as 200 bar at a sample spinning rate of 6 kHz is achieved. The new high pressure MAS rotor is re-usable and compatible with most commercial NMR set-ups, exhibiting low 1H and 13C NMR background and offering maximal NMR sensitivity. As an example of its many possible applications, this new capability is applied to determine reaction products associated with the carbonation reaction of a natural mineral, antigorite ((Mg,Fe2+)3Si2O5(OH)4), in contact with liquid water in water-saturated supercritical CO2 (scCO2) at 150 bar and 50 °C. This mineral is relevant to the deep geologic disposal of CO2, but its iron content results in too many sample spinning sidebands at low spinning rate. Hence, this chemical system is a good case study to demonstrate the utility of the higher sample spinning rates that can be achieved by our new rotor design. We expect this new capability will be useful for exploring solid-state, including interfacial, chemistry at new levels of high-pressure in a wide variety of fields.

Turcu, Romulus V. F.; Hoyt, David W.; Rosso, Kevin M.; Sears, Jesse A.; Loring, John S.; Felmy, Andrew R.; Hu, Jian Zhi

2013-01-01

425

Research program in nuclear and solid state physics. [including pion absorption spectra and muon spin precession  

NASA Technical Reports Server (NTRS)

The survey of negative pion absorption reactions on light and medium nuclei was continued. Muon spin precession was studied using an iron target. An impulse approximation model of the pion absorption process implied that the ion will absorb almost exclusively on nucleon pairs, single nucleon absorption being suppressed by energy and momentum conservation requirements. For measurements on both paramagnetic and ferromagnetic iron, the external magnetic field was supplied by a large C-type electromagnet carrying a current of about 100 amperes.

1974-01-01

426

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

NASA Astrophysics Data System (ADS)

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.

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

427

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

NASA Astrophysics Data System (ADS)

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.

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,