A spin-valve-like magnetoresistance of an antiferromagnet-based tunnel junction.
Park, B G; Wunderlich, J; Martí, X; Holý, V; Kurosaki, Y; Yamada, M; Yamamoto, H; Nishide, A; Hayakawa, J; Takahashi, H; Shick, A B; Jungwirth, T
2011-05-01
A spin valve is a microelectronic device in which high- and low-resistance states are realized by using both the charge and spin of carriers. Spin-valve structures used in modern hard-drive read heads and magnetic random access memoriescomprise two ferromagnetic electrodes whose relative magnetization orientations can be switched between parallel and antiparallel configurations, yielding the desired giant or tunnelling magnetoresistance effect. Here we demonstrate more than 100% spin-valve-like signal in a NiFe/IrMn/MgO/Pt stack with an antiferromagnet on one side and a non-magnetic metal on the other side of the tunnel barrier. Ferromagneticmoments in NiFe are reversed by external fields of approximately 50 mT or less, and the exchange-spring effect of NiFe on IrMn induces rotation of antiferromagnetic moments in IrMn, which is detected by the measured tunnelling anisotropic magnetoresistance. Our work demonstrates a spintronic element whose transport characteristics are governed by an antiferromagnet. It demonstrates that sensitivity to low magnetic fields can be combined with large, spin-orbit-coupling-induced magnetotransport anisotropy using a single magnetic electrode. The antiferromagnetic tunnelling anisotropic magnetoresistance provides a means to study magnetic characteristics of antiferromagnetic films by an electronic-transport measurement. PMID:21399629
Dynamic nuclear spin polarization
Energy Technology Data Exchange (ETDEWEB)
Stuhrmann, H.B. [GKSS-Forschungszentrum Geesthacht GmbH (Germany)
1996-11-01
Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.
Nuclear spin effect in metallic spin valve
Danon, J.; Nazarov, Yu.V.
2006-01-01
We study electronic transport through a ferromagnet normal-metal ferromagnet system and we investigate the effect of hyperfine interaction between electrons and nuclei in the normal-metal part. A switching of the magnetization directions of the ferromagnets causes nuclear spins to precess. We show that the effect of this precession on the current through the system is large enough to be observed in experiment.
Müller, Norbert; Jerschow, Alexej
2006-01-01
NMR images were obtained from the proton spin noise signals of a water-containing phantom, which was placed in the highly tuned, low-noise resonant circuit of a cryogenically cooled NMR probe in the presence of systematically varied magnetic field gradients. The spatially resolved proton spin density was obtained from the raw signal by a modified projection–reconstruction protocol. Although spin noise imaging is inherently less sensitive than conventional magnetic resonance imaging, it afford...
Measurements of nuclear spin dynamics by spin-noise spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Ryzhov, I. I.; Poltavtsev, S. V.; Kozlov, G. G.; Zapasskii, V. S. [Spin Optics Laboratory, St. Petersburg State University, 1 Ul' anovskaya, Peterhof, St. Petersburg 198504 (Russian Federation); Kavokin, K. V.; Glazov, M. M. [Spin Optics Laboratory, St. Petersburg State University, 1 Ul' anovskaya, Peterhof, St. Petersburg 198504 (Russian Federation); Ioffe Institute, Russian Academy of Sciences, 26 Polytechnicheskaya, St.-Petersburg 194021 (Russian Federation); Vladimirova, M.; Scalbert, D.; Cronenberger, S. [Laboratoire Charles Coulomb UMR 5221 CNRS/Université de Montpellier, Place Eugene Bataillon, 34095 Montpellier Cedex 05 (France); Kavokin, A. V. [Spin Optics Laboratory, St. Petersburg State University, 1 Ul' anovskaya, Peterhof, St. Petersburg 198504 (Russian Federation); School of Physics and Astronomy, University of Southampton, SO17 1NJ Southampton (United Kingdom); Lemaître, A.; Bloch, J. [Laboratoire de Photonique et de Nanostructures, UPR CNRS, Route de Nozay, 91460 Marcoussis (France)
2015-06-15
We exploit the potential of the spin noise spectroscopy (SNS) for studies of nuclear spin dynamics in n-GaAs. The SNS experiments were performed on bulk n-type GaAs layers embedded into a high-finesse microcavity at negative detuning. In our experiments, nuclear spin polarisation initially prepared by optical pumping is monitored in real time via a shift of the peak position in the electron spin noise spectrum. We demonstrate that this shift is a direct measure of the Overhauser field acting on the electron spin. The dynamics of nuclear spin is shown to be strongly dependent on the electron concentration.
Electron spin decoherence in nuclear spin baths and dynamical decoupling
International Nuclear Information System (INIS)
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.
High-spin nuclear spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Diamond, R.M.
1986-07-01
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)
International Nuclear Information System (INIS)
Imaging techniques of computerised axial tomography, positron emission tomography and imaging by nuclear magnetic resonance, and their application in medicine for diagnostic purposes are described. These techniques are compared, and their relative merits and limitations are mentioned. (M.G.B.)
Nuclear Spin Noise and STM Noise Spectroscopy
Balatsky, A. V.; Fransson, J.; Mozyrsky, D.; Manassen, Yishay
2006-01-01
We consider fluctuations of the electronic spin due to coupling to nuclear spin. Noise spectroscopy of an electronic spin can be revealed in the Scanning Tunnelling Microscope (STM). We argue that the noise spectroscopy of electronic spin can reveal the nuclear spin dynamics due to hyperfine coupling. Tunnelling current develops satellites of the main lines at Larmor frequency and at zero frequency due to hyperfine coupling. We also address the role of the rf field that is at or near the reso...
Decoupling a hole spin qubit from the nuclear spins
Prechtel, Jonathan H.; Kuhlmann, Andreas V.; Houel, Julien; Ludwig, Arne; Valentin, Sascha R.; Wieck, Andreas D.; Warburton, Richard J.
2016-09-01
A huge effort is underway to develop semiconductor nanostructures as low-noise hosts for qubits. The main source of dephasing of an electron spin qubit in a GaAs-based system is the nuclear spin bath. A hole spin may circumvent the nuclear spin noise. In principle, the nuclear spins can be switched off for a pure heavy-hole spin. In practice, it is unknown to what extent this ideal limit can be achieved. A major hindrance is that p-type devices are often far too noisy. We investigate here a single hole spin in an InGaAs quantum dot embedded in a new generation of low-noise p-type device. We measure the hole Zeeman energy in a transverse magnetic field with 10 neV resolution by dark-state spectroscopy as we create a large transverse nuclear spin polarization. The hole hyperfine interaction is highly anisotropic: the transverse coupling is energies; equivalently dephasing times up to a microsecond. The combination of large and strong optical dipole makes the single hole spin in a GaAs-based device an attractive quantum platform.
Nuclear Spin Dynamics in Parabolic Quantum Wells
Tifrea, I.; Flatte, Michael E.
2003-01-01
We present a detailed analytical and numerical analysis of the nuclear spin dynamics in parabolic quantum wells. The shallow potential of parabolic quantum wells permits substantial modification of the electronic wave function in small electric fields. The nuclear spin relaxation via the hyperfine interaction depends on the electronic local density of states, therefore the local nuclear relaxation time depends sensitively on the electric field. For an inhomogeneous nuclear magnetization, such...
Nuclear spin noise in NMR revisited
Energy Technology Data Exchange (ETDEWEB)
Ferrand, Guillaume; Luong, Michel [Laboratoire d’Ingénierie des Systèmes Accélérateurs et des Hyperfréquences, SACM, CEA, Université Paris-Saclay, CEA/Saclay, F-91191 Gif-sur-Yvette (France); Huber, Gaspard; Desvaux, Hervé, E-mail: herve.desvaux@cea.fr [Laboratoire Structure et Dynamique par Résonance Magnétique, NIMBE, CEA, CNRS, Université Paris-Saclay, CEA/Saclay, F-91191 Gif-sur-Yvette (France)
2015-09-07
The theoretical shapes of nuclear spin-noise spectra in NMR are derived by considering a receiver circuit with finite preamplifier input impedance and a transmission line between the preamplifier and the probe. Using this model, it becomes possible to reproduce all observed experimental features: variation of the NMR resonance linewidth as a function of the transmission line phase, nuclear spin-noise signals appearing as a “bump” or as a “dip” superimposed on the average electronic noise level even for a spin system and probe at the same temperature, pure in-phase Lorentzian spin-noise signals exhibiting non-vanishing frequency shifts. Extensive comparisons to experimental measurements validate the model predictions, and define the conditions for obtaining pure in-phase Lorentzian-shape nuclear spin noise with a vanishing frequency shift, in other words, the conditions for simultaneously obtaining the spin-noise and frequency-shift tuning optima.
Nuclear spin noise in NMR revisited
International Nuclear Information System (INIS)
The theoretical shapes of nuclear spin-noise spectra in NMR are derived by considering a receiver circuit with finite preamplifier input impedance and a transmission line between the preamplifier and the probe. Using this model, it becomes possible to reproduce all observed experimental features: variation of the NMR resonance linewidth as a function of the transmission line phase, nuclear spin-noise signals appearing as a “bump” or as a “dip” superimposed on the average electronic noise level even for a spin system and probe at the same temperature, pure in-phase Lorentzian spin-noise signals exhibiting non-vanishing frequency shifts. Extensive comparisons to experimental measurements validate the model predictions, and define the conditions for obtaining pure in-phase Lorentzian-shape nuclear spin noise with a vanishing frequency shift, in other words, the conditions for simultaneously obtaining the spin-noise and frequency-shift tuning optima
Nuclear spin noise in NMR revisited
Ferrand, Guillaume; Huber, Gaspard; Luong, Michel; Desvaux, Hervé
2015-09-01
The theoretical shapes of nuclear spin-noise spectra in NMR are derived by considering a receiver circuit with finite preamplifier input impedance and a transmission line between the preamplifier and the probe. Using this model, it becomes possible to reproduce all observed experimental features: variation of the NMR resonance linewidth as a function of the transmission line phase, nuclear spin-noise signals appearing as a "bump" or as a "dip" superimposed on the average electronic noise level even for a spin system and probe at the same temperature, pure in-phase Lorentzian spin-noise signals exhibiting non-vanishing frequency shifts. Extensive comparisons to experimental measurements validate the model predictions, and define the conditions for obtaining pure in-phase Lorentzian-shape nuclear spin noise with a vanishing frequency shift, in other words, the conditions for simultaneously obtaining the spin-noise and frequency-shift tuning optima.
Nuclear spin noise in NMR revisited
Ferrand, Guillaume; Luong, Michel; Desvaux, Hervé
2015-01-01
The theoretical shapes of nuclear spin-noise spectra in NMR are derived by considering a receiver circuit with finite, preamplifier input impedance and a transmission line between the preamplifier and the probe. Using this model, it becomes possible to reproduce all observed experimental features: variation of the NMR resonance linewidth as a function of the transmission line phase, nuclear spin-noise signals appearing as a "bump" or as a "dip" superimposed on the average electronic noise level even for a spin system and probe at the same temperature, pure in-phase Lorentzian spin-noise signals exhibiting non-vanishing frequency shifts. Extensive comparison to experimental measurements validate the model predictions, and define the conditions for obtaining pure in-phase Lorentzian-shape nuclear spin noise with a vanishing frequency shift, in other words, the conditions for simultaneously obtaining the Spin-Noise and Frequency-Shift Tuning Optima.
Detecting and polarizing nuclear spins in diamond
International Nuclear Information System (INIS)
Control and measurement of nuclear spins is essential for medicine, chemistry and physics, but the sensitivity of conventional measurement schemes is limited due to low thermal polarization of nuclei under ambient conditions. We use an electron-nuclear double resonance technique, known as Hartmann-Hahn double resonance, to demonstrate experimentally polarization of single and multiple nuclear spins in a room temperature solid. By transferring polarization from an optically cooled electron spin associated with the nitrogen-vacancy (NV) defect, to carbon nuclei we are able to control spin bath dynamics. This work opens new possibilities for different fields of science, from control over decoherence and use of mesoscopic ensemble of nuclear spins as qubits to enhancement of contrast in magnetic resonance imaging.
Optical nuclear spin polarization in quantum dots
Li, Ai-Xian; Duan, Su-Qing; Zhang, Wei
2016-10-01
Hyperfine interaction between electron spin and randomly oriented nuclear spins is a key issue of electron coherence for quantum information/computation. We propose an efficient way to establish high polarization of nuclear spins and reduce the intrinsic nuclear spin fluctuations. Here, we polarize the nuclear spins in semiconductor quantum dot (QD) by the coherent population trapping (CPT) and the electric dipole spin resonance (EDSR) induced by optical fields and ac electric fields. By tuning the optical fields, we can obtain a powerful cooling background based on CPT for nuclear spin polarization. The EDSR can enhance the spin flip-flop rate which may increase the cooling efficiency. With the help of CPT and EDSR, an enhancement of 1300 times of the electron coherence time can be obtained after a 10-ns preparation time. Project partially supported by the National Natural Science Foundations of China (Grant Nos. 11374039 and 11174042) and the National Basic Research Program of China (Grant Nos. 2011CB922204 and 2013CB632805).
Spin excitations in di-nuclear systems
International Nuclear Information System (INIS)
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 γ-multiplicities in 238U induced quasi-fission reactions and it is concluded that the spin-excitation are only partially equilibrated during the interaction. 11 refs., 5 figs
Nuclear Spin Effect in a Metallic Spin Valve
Danon, J.; Nazarov, Y.V.
2006-01-01
We study electronic transport through a ferromagnet normal-metal ferromagnet system and we investigate the effect of hyperfine interaction between electrons and nuclei in the normal-metal part. A switching of the magnetization directions of the ferromagnets causes nuclear spins to precess. We show t
Spin-Polarized States of Nuclear Matter
Institute of Scientific and Technical Information of China (English)
ZUO Wei; U. Lombardo; SHEN Cai-Wan
2003-01-01
The equations of state of spin-polarized nuclear matter and pure neutron matter are studied in theframework of the Brueckner-Hartree-Fock theory including a three-body force. The energy per nucleon E A (δ) calculatedin the full range of spin polarization δ = (ρ↑ - ρ↓)/ρ for symmetric nuclear matter and pure neutron matter fulfills aparabolic law. In both the cases the spin-symmetry energy is calculated as a function of the baryonic density alongwith the related quantities such as the magnetic susceptibility and the Landau parameter Go. The main effect of thethree-body force is to strongly reduce the degenerate Fermi gas magnetic susceptibility even more than the value withonly two-body force. The equation of state is monotonically increasing with the density for all spin-aligned configurationsstudied here so that no any signature is found for a spontaneous transition to a ferromagnetic state.
Nonergodic dynamics of nuclear spin 1/2 with equal constants of spin-spin interaction
Rudavets, M G
2002-01-01
The exact solution of the nuclear spins polarization evolution in the system with the similar q-constant spin-spin interaction (SSI) between all spin pairs is obtained in the case when only one (the first) spin was polarized at the initial time moment. It is shown that polarization of the first spin P sub 1 (t) has the form of periodical pulsations in the time with the 4 pi/g period. The P sub 1 (t) function changes in each period from the initial value P(0) = 1 up to 1/3 value during the time period of the t approx = 4 pi/Ng order, when the spins number is N >= 1 and remains in the P sub 1 (t) 1/3 state practically during the whole period. The simple classical model within the frames of the average field theory explains the physical cause of the nonergodic dynamics of the considered system
Isobaric-spin relationships between nuclear spectra
French, J.B.
1961-01-01
The simple fact that a one-body energy describes the interaction of a nucleon with a closed neutron subshell is used to establish sets of equations connecting the spectra of nuclei which are related by isobaric-spin when described by means of the nuclear shell model. Certain formal questions about i
Nuclear spin quantum computing with trapped ions
Wang, Kunling; Feng, Mang; Mintert, Florian; Wunderlich, Christof
2011-01-01
Quantum computing with qubits encoded in nuclear spins of trapped ions is studied with particular attention to the Yb$^+$ ion. For this purpose we consider the Paschen-Back regime (strong magnetic field) and employ a high-field approximation in this treatment. An efficient scheme is proposed to carry out gate operations on an array of trapped ions, and the feasibility of generating the required high magnetic field is discussed.
Hydrodynamic approach to coherent nuclear spin transport
Greenbaum, D.; Kindermann, M.; Ramanathan, C.; Cory, D. G.
2004-01-01
We develop a linear response formalism for nuclear spin diffusion in a dipolar coupled solid. The theory applies to the high-temperature, long-wavelength regime studied in the recent experiments of Boutis et al. [Phys. Rev. Lett. 92, 137201 (2004)], which provided direct measurement of interspin energy diffusion in such a system. A systematic expansion of Kubo's formula in the flip-flop term of the Hamiltonian is used to calculate the diffusion coefficients. We show that this approach is equi...
Pumping of nuclear spins by optical excitation of spin-forbidden transitions in a quantum dot.
Chekhovich, E A; Makhonin, M N; Kavokin, K V; Krysa, A B; Skolnick, M S; Tartakovskii, A I
2010-02-12
We demonstrate that efficient optical pumping of nuclear spins in semiconductor quantum dots (QDs) can be achieved by resonant pumping of optically forbidden transitions. This process corresponds to one-to-one conversion of a photon absorbed by the dot into a polarized nuclear spin, and also has potential for initialization of hole spin in QDs. We find that by employing this spin-forbidden process, nuclear polarization of 65% can be achieved, markedly higher than from pumping the allowed transition, which saturates due to the low probability of electron-nuclear spin flip-flop.
Evolution of nuclear shapes at high spins
International Nuclear Information System (INIS)
The dynamic electric quadrupole (E2) moments are a direct reflection of the collective aspects of the nuclear wave functions. For this, Doppler-shift lifetime measurements have been done utilizing primarily the recoil-distance technique. The nuclei with neutron number N approx. 90 possess many interesting properties. These nuclei have very shallow minima in their potential energy surfaces, and thus, are very susceptible to deformation driving influences. It is the evolution of nuclear shapes as a function of spin or rotational frequency for these nuclei that has commanded much interest in the lifetime measurements discussed here. There is growing evidence that many deformed nuclei which have prolate shapes in their ground states conform to triaxial or oblate shapes at higher spins. Since the E2 matrix elements along the yrast line are sensitive indicators of deformation changes, measurements of lifetimes of these states to provide the matrix elements has become the major avenue for tracing the evolving shape of a nucleus at high spin. Of the several nuclei we have studied with N approx. 90, those to be discussed here are /sup 160,161/Yb and 158Er. In addition, the preliminary, but interesting and surprising results from our recent investigation of the N = 98 nucleus, 172W are briefly discussed. 14 refs., 5 figs
Detection and manipulation of nuclear spin states in fermionic strontium
Energy Technology Data Exchange (ETDEWEB)
Stellmer, Simon; Grimm, Rudolf [Institut fuer Quantenoptik und Quanteninformation (IQOQI), Oesterreichische Akademie der Wissenschaften, A-6020 Innsbruck (Austria); Institut fuer Experimentalphysik und Zentrum fuer Quantenphysik, Universitaet Innsbruck, A-6020 Innsbruck (Austria); Schreck, Florian [Institut fuer Quantenoptik und Quanteninformation (IQOQI), Oesterreichische Akademie der Wissenschaften, A-6020 Innsbruck (Austria)
2011-10-15
Fermionic {sup 87}Sr has a nuclear spin of I=9/2, higher than any other element with a similar electronic structure. This large nuclear spin has many applications in quantum simulation and computation, for which preparation and detection of the spin state are requirements. For an ultracold {sup 87}Sr cloud, we show two complementary methods to characterize the spin-state mixture: optical Stern-Gerlach state separation and state-selective absorption imaging. We use these methods to optimize the preparation of a variety of spin-state mixtures by optical pumping and to measure an upper bound of the {sup 87}Sr spin-relaxation rate.
Nuclear spin pair coherence in diamond for atomic scale magnetometry
Zhao, Nan; Hu, Jian-Liang; Ho, Sai-Wah; Wen, Tsz-Kai; Liu, R. B.
2010-01-01
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 inform...
Atomic-scale magnetometry of distant nuclear spin clusters via nitrogen-vacancy spin in diamond.
Zhao, Nan; Hu, Jian-Liang; Ho, Sai-Wah; Wan, Jones T K; Liu, R B
2011-04-01
The detection of single nuclear spins is an important goal in magnetic resonance spectroscopy. Optically detected magnetic resonance can detect single nuclear spins that are strongly coupled to an electron spin, but the detection of distant nuclear spins that are only weakly coupled to the electron spin has not been considered feasible. Here, using the nitrogen-vacancy centre in diamond as a model system, we numerically demonstrate that it is possible to detect two or more distant nuclear spins that are weakly coupled to a centre electron spin if these nuclear spins are strongly bonded to each other in a cluster. This cluster will stand out from other nuclear spins by virtue of characteristic oscillations imprinted onto the electron spin decoherence profile, which become pronounced under dynamical decoupling control. Under many-pulse dynamical decoupling, the centre electron spin coherence can be used to measure nuclear magnetic resonances of single molecules. This atomic-scale magnetometry should improve the performance of magnetic resonance spectroscopy for applications in chemical, biological, medical and materials research, and could also have applications in solid-state quantum computing. PMID:21358646
Nuclear spin polarized H and D by means of spin-exchange optical pumping
Stenger, Jörn; Grosshauser, Carsten; Kilian, Wolfgang; Nagengast, Wolfgang; Ranzenberger, Bernd; Rith, Klaus; Schmidt, Frank
1998-01-01
Optically pumped spin-exchange sources for polarized hydrogen and deuterium atoms have been demonstrated to yield high atomic flow and high electron spin polarization. For maximum nuclear polarization the source has to be operated in spin temperature equilibrium, which has already been demonstrated for hydrogen. In spin temperature equilibrium the nuclear spin polarization PI equals the electron spin polarization PS for hydrogen and is even larger than PS for deuterium. We discuss the general properties of spin temperature equilibrium for a sample of deuterium atoms. One result are the equations PI=4PS/(3+PS2) and Pzz=PSṡPI, where Pzz is the nuclear tensor polarization. Furthermore we demonstrate that the deuterium atoms from our source are in spin temperature equilibrium within the experimental accuracy.
Park, Kisam; Light, John C
2007-12-14
The spin-modification probability (SMP) method, which provides fundamental and detailed quantitative information on the nuclear spin selection rules, is discussed more systematically and generalized for reactive collision systems involving more than one configuration of reactant and product molecules, explicitly taking account of the conservation of the overall nuclear spin symmetry as well as the conservation of the total nuclear spin angular momentum, under the assumption of no nuclear hyperfine interaction. The values of SMP once calculated can be used for any system of identical nuclei of any spin as long as the system has the corresponding nuclear spin symmetry. The values of SMP calculated for simple systems can also be used for more complex systems containing several kinds of identical nuclei or various isotopomers. The generalized formulation of statistical scattering theory which can easily represent various rearrangement mechanisms is also presented.
Nuclear magnetometry studies of spin dynamics in quantum Hall systems
Fauzi, M. H.; Watanabe, S.; Hirayama, Y.
2014-12-01
We performed a nuclear magnetometry study on quantum Hall ferromagnet with a bilayer total filling factor of νtot=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.
Thermodynamics of Rh nuclear spins calculated by exact diagonalization
DEFF Research Database (Denmark)
Lefmann, K.; Ipsen, J.; Rasmussen, F.B.
2000-01-01
We have employed the method of exact diagonalization to obtain the full-energy spectrum of a cluster of 16 Rh nuclear spins, having dipolar and RK interactions between first and second nearest neighbours only. We have used this to calculate the nuclear spin entropy, and our results at both positi...
Spin squeezing of atomic ensembles via nuclear-electronic spin entanglement
DEFF Research Database (Denmark)
Fernholz, Thomas; Krauter, Hanna; Jensen, Kasper;
2008-01-01
We demonstrate spin squeezing in a room temperature ensemble of 1012 Cesium atoms using their internal structure, where the necessary entanglement is created between nuclear and electronic spins of each individual atom. This state provides improvement in measurement sensitivity beyond the standard...... quantum limit for quantum memory experiments and applications in quantum metrology and is thus a complementary alternative to spin squeezing obtained via inter-atom entanglement. Squeezing of the collective spin is verified by quantum state tomography....
Optically induced dynamic nuclear spin polarisation in diamond
Scheuer, Jochen; Schwartz, Ilai; Chen, Qiong; Schulze-Sünninghausen, David; Carl, Patrick; Höfer, Peter; Retzker, Alexander; Sumiya, Hitoshi; Isoya, Junichi; Luy, Burkhard; Plenio, Martin B.; Naydenov, Boris; Jelezko, Fedor
2016-01-01
The sensitivity of magnetic resonance imaging (MRI) depends strongly on nuclear spin polarisation and, motivated by this observation, dynamical nuclear spin polarisation has recently been applied to enhance MRI protocols (Kurhanewicz et al 2011 Neoplasia 13 81). Nuclear spins associated with the 13C carbon isotope (nuclear spin I = 1/2) in diamond possess uniquely long spin lattice relaxation times (Reynhardt and High 2011 Prog. Nucl. Magn. Reson. Spectrosc. 38 37). If they are present in diamond nanocrystals, especially when strongly polarised, they form a promising contrast agent for MRI. Current schemes for achieving nuclear polarisation, however, require cryogenic temperatures. Here we demonstrate an efficient scheme that realises optically induced 13C nuclear spin hyperpolarisation in diamond at room temperature and low ambient magnetic field. Optical pumping of a nitrogen-vacancy centre creates a continuously renewable electron spin polarisation which can be transferred to surrounding 13C nuclear spins. Importantly for future applications we also realise polarisation protocols that are robust against an unknown misalignment between magnetic field and crystal axis.
Dynamical nuclear spin polarization in a double quantum dot
Ramon, Guy; Deng, Changxue; Hu, Xuedong
2006-03-01
The hyperfine interaction between an electron spin confined in a semiconductor quantum dot and the nuclear spins in the surrounding lattice has been identified as one of the main sources for decoherence in low temperature GaAs quantum dots. Recent experiments in gated double dot systems [1] have attempted to utilize the degeneracy point between the two-electron singlet and polarized triplet states to polarize the nuclear spins, thereby reducing their decoherence effects on the electron spins. Here we analyze the dynamics of the system of two electrons and a nuclear spin bath subject to the hyperfine interaction. We consider the effective spin Hamiltonian for the two-electron system, and represent the nuclear spins in the basis of their collective states. The nuclear polarization rates are evaluated for various initial conditions of the nuclear spin system, and optimal conditions for efficient polarization are discussed. [1] J. R. Petta, A. C. Johnson, J. M. Taylor, E. A. Laird, A. Yacoby, M. D. Lukin, C. M. Marcus, M. P. Hanson, A. C. Gossard, Science 309, 2180 (2005).
Preparation of Nuclear Spin Singlet States using Spin-Lock Induced Crossing
DeVience, Stephen J; Rosen, Matthew S
2013-01-01
We introduce a broadly applicable technique to create nuclear spin singlet states in organic molecules and other many-atom systems. We employ a novel pulse sequence to produce a spin-lock induced crossing (SLIC) of the spin singlet and triplet energy levels, which enables triplet/singlet polarization transfer and singlet state preparation. We demonstrate the utility of the SLIC method by producing a long-lived nuclear spin singlet state on two strongly-coupled proton pairs in the tripeptide molecule phenylalanine-glycine-glycine dissolved in D2O, and by using SLIC to measure the J-couplings, chemical shift differences, and singlet lifetimes of the proton pairs. We show that SLIC is more efficient at creating nearly-equivalent nuclear spin singlet states than previous pulse sequence techniques, especially when triplet/singlet polarization transfer occurs on the same timescale as spin-lattice relaxation.
Sensitive Magnetic Control of Ensemble Nuclear Spin Hyperpolarisation in Diamond
Wang, Hai-Jing; Avalos, Claudia E; Seltzer, Scott J; Budker, Dmitry; Pines, Alexander; Bajaj, Vikram S
2012-01-01
Dynamic nuclear polarisation, which transfers the spin polarisation of electrons to nuclei, is routinely applied to enhance the sensitivity of nuclear magnetic resonance; it is also critical in spintronics, particularly when spin hyperpolarisation can be produced and controlled optically or electrically. Here we show the complete polarisation of nuclei located near the optically-polarised nitrogen-vacancy (NV) centre in diamond. When approaching the ground-state level anti-crossing condition of the NV electron spins, 13C nuclei in the first-shell are polarised in a pattern that depends sensitively and sharply upon the magnetic field. Based on the anisotropy of the hyperfine coupling and of the optical polarisation mechanism, we predict and observe a complete reversal of the nuclear spin polarisation with a few-mT change in the magnetic field. The demonstrated sensitive magnetic control of nuclear polarisation at room temperature will be useful for sensitivity-enhanced NMR, nuclear-based spintronics, and quant...
Decoupling a hole spin qubit from the nuclear spins.
Prechtel, Jonathan H; Kuhlmann, Andreas V; Houel, Julien; Ludwig, Arne; Valentin, Sascha R; Wieck, Andreas D; Warburton, Richard J
2016-09-01
A huge effort is underway to develop semiconductor nanostructures as low-noise hosts for qubits. The main source of dephasing of an electron spin qubit in a GaAs-based system is the nuclear spin bath. A hole spin may circumvent the nuclear spin noise. In principle, the nuclear spins can be switched off for a pure heavy-hole spin. In practice, it is unknown to what extent this ideal limit can be achieved. A major hindrance is that p-type devices are often far too noisy. We investigate here a single hole spin in an InGaAs quantum dot embedded in a new generation of low-noise p-type device. We measure the hole Zeeman energy in a transverse magnetic field with 10 neV resolution by dark-state spectroscopy as we create a large transverse nuclear spin polarization. The hole hyperfine interaction is highly anisotropic: the transverse coupling is energies; equivalently dephasing times up to a microsecond. The combination of large and strong optical dipole makes the single hole spin in a GaAs-based device an attractive quantum platform. PMID:27454044
Quantum dot spin coherence governed by a strained nuclear environment.
Stockill, R; Le Gall, C; Matthiesen, C; Huthmacher, L; Clarke, E; Hugues, M; Atatüre, M
2016-01-01
The interaction between a confined electron and the nuclei of an optically active quantum dot provides a uniquely rich manifestation of the central spin problem. Coherent qubit control combines with an ultrafast spin-photon interface to make these confined spins attractive candidates for quantum optical networks. Reaching the full potential of spin coherence has been hindered by the lack of knowledge of the key irreversible environment dynamics. Through all-optical Hahn echo decoupling we now recover the intrinsic coherence time set by the interaction with the inhomogeneously strained nuclear bath. The high-frequency nuclear dynamics are directly imprinted on the electron spin coherence, resulting in a dramatic jump of coherence times from few tens of nanoseconds to the microsecond regime between 2 and 3 T magnetic field and an exponential decay of coherence at high fields. These results reveal spin coherence can be improved by applying large magnetic fields and reducing strain inhomogeneity. PMID:27615704
Effect of nuclear spins on the electron spin dynamics in negatively charged InP quantum dots
Ignatiev, I. V.; Verbin, S. Yu.; Gerlovin, I. Ya.; Maruyama, W.; Pal, B.; Masumoto, Y.
2005-01-01
Kinetics of polarized photoluminescence of the negatively charged InP quantum dots in weak magnetic field is studied experimentally. Effect of both the nuclear spin fluctuations and the dynamical nuclear polarization on the electron spin orientation is observed.
Single-shot readout of a single nuclear spin.
Neumann, Philipp; Beck, Johannes; Steiner, Matthias; Rempp, Florian; Fedder, Helmut; Hemmer, Philip R; Wrachtrup, Jörg; Jelezko, Fedor
2010-07-30
Projective measurement of single electron and nuclear spins has evolved from a gedanken experiment to a problem relevant for applications in atomic-scale technologies like quantum computing. Although several approaches allow for detection of a spin of single atoms and molecules, multiple repetitions of the experiment that are usually required for achieving a detectable signal obscure the intrinsic quantum nature of the spin's behavior. We demonstrated single-shot, projective measurement of a single nuclear spin in diamond using a quantum nondemolition measurement scheme, which allows real-time observation of an individual nuclear spin's state in a room-temperature solid. Such an ideal measurement is crucial for realization of, for example, quantum error correction protocols in a quantum register. PMID:20595582
Nuclear Spin Conversion in CH4: A Multichannel Relaxation Mechanism.
Cacciani, Patrice; Cosléou, Jean; Khelkhal, Mohamed; Čermák, Peter; Puzzarini, Cristina
2016-01-21
Experiments on nuclear spin interconversion of ortho, para, and meta nuclear spin isomers of the methane molecule have been undertaken in gas phase and cryomatrices. Only the latter environment has led to the observation of the nuclear spin conversion. In this study, a quantitative explanation is given for the first time by considering the coupling of three relaxation paths: meta ⇔ para, meta ⇔ ortho, and ortho ⇔ para. The global evolution of the three populations of spin isomers is thus described by two characteristic times, which have been calculated using the best values of the energy levels for the vibrational ground state, of the intramolecular magnetic interactions, and of the collisional relaxation rates, and for different pressure and temperature conditions. Such calculations also provide an indication for the proper choice of reliable scenarios for experimental separation of the spin isomers of methane. PMID:26681482
Spin-Orbit Interaction of Nuclear Shell Structure
Wang, Xiaobin; Wang, Zhengda; Wang, Xiaochun; Zhang, Xiaodong
2012-01-01
Single particle spin-orbit interaction energy problem in nuclear shell structure is solved through negative harmonic oscillator in the self-similar-structure shell model (SSM) [4] and considering quarks' contributions on single particle spin and orbit momentum. The paper demonstrates that single particle motion in normal nuclei is described better by SSM negative harmonic oscillator than conventional shell model positive harmonic oscillator[1][2][3]. The proposed theoretical formula for spin ...
Calculations of the indirect nuclear spin-spin coupling constants of PbH_{4}
DEFF Research Database (Denmark)
Kirpekar, Sheela; Sauer, Stephan P. A.
1999-01-01
We report ab initio calculations of the indirect nuclear spin-spin coupling constants of PbH4 using a basis set which was specially optimized for correlated calculations of spin-spin coupling constants. All nonrelativistic contributions and the most important part of the spin-orbit correction wer...
Quantum computation with nuclear spins in quantum dots
Energy Technology Data Exchange (ETDEWEB)
Christ, H.
2008-01-24
The role of nuclear spins for quantum information processing in quantum dots is theoretically investigated in this thesis. Building on the established fact that the most strongly coupled environment for the potential electron spin quantum bit are the surrounding lattice nuclear spins interacting via the hyperfine interaction, we turn this vice into a virtue by designing schemes for harnessing this strong coupling. In this perspective, the ensemble of nuclear spins can be considered an asset, suitable for an active role in quantum information processing due to its intrinsic long coherence times. We present experimentally feasible protocols for the polarization, i.e. initialization, of the nuclear spins and a quantitative solution to our derived master equation. The polarization limiting destructive interference effects, caused by the collective nature of the nuclear coupling to the electron spin, are studied in detail. Efficient ways of mitigating these constraints are presented, demonstrating that highly polarized nuclear ensembles in quantum dots are feasible. At high, but not perfect, polarization of the nuclei the evolution of an electron spin in contact with the spin bath can be efficiently studied by means of a truncation of the Hilbert space. It is shown that the electron spin can function as a mediator of universal quantum gates for collective nuclear spin qubits, yielding a promising architecture for quantum information processing. Furthermore, we show that at high polarization the hyperfine interaction of electron and nuclear spins resembles the celebrated Jaynes-Cummings model of quantum optics. This result opens the door for transfer of knowledge from the mature field of quantum computation with atoms and photons. Additionally, tailored specifically for the quantum dot environment, we propose a novel scheme for the generation of highly squeezed collective nuclear states. Finally we demonstrate that even an unprepared completely mixed nuclear spin
Quantum computation with nuclear spins in quantum dots
International Nuclear Information System (INIS)
The role of nuclear spins for quantum information processing in quantum dots is theoretically investigated in this thesis. Building on the established fact that the most strongly coupled environment for the potential electron spin quantum bit are the surrounding lattice nuclear spins interacting via the hyperfine interaction, we turn this vice into a virtue by designing schemes for harnessing this strong coupling. In this perspective, the ensemble of nuclear spins can be considered an asset, suitable for an active role in quantum information processing due to its intrinsic long coherence times. We present experimentally feasible protocols for the polarization, i.e. initialization, of the nuclear spins and a quantitative solution to our derived master equation. The polarization limiting destructive interference effects, caused by the collective nature of the nuclear coupling to the electron spin, are studied in detail. Efficient ways of mitigating these constraints are presented, demonstrating that highly polarized nuclear ensembles in quantum dots are feasible. At high, but not perfect, polarization of the nuclei the evolution of an electron spin in contact with the spin bath can be efficiently studied by means of a truncation of the Hilbert space. It is shown that the electron spin can function as a mediator of universal quantum gates for collective nuclear spin qubits, yielding a promising architecture for quantum information processing. Furthermore, we show that at high polarization the hyperfine interaction of electron and nuclear spins resembles the celebrated Jaynes-Cummings model of quantum optics. This result opens the door for transfer of knowledge from the mature field of quantum computation with atoms and photons. Additionally, tailored specifically for the quantum dot environment, we propose a novel scheme for the generation of highly squeezed collective nuclear states. Finally we demonstrate that even an unprepared completely mixed nuclear spin
Analysis of the transient response of nuclear spins in GaAs with/without nuclear magnetic resonance
Rasly, Mahmoud; Lin, Zhichao; Yamamoto, Masafumi; Uemura, Tetsuya
2016-05-01
As an alternative to studying the steady-state responses of nuclear spins in solid state systems, working within a transient-state framework can reveal interesting phenomena. The response of nuclear spins in GaAs to a changing magnetic field was analyzed based on the time evolution of nuclear spin temperature. Simulation results well reproduced our experimental results for the transient oblique Hanle signals observed in an all-electrical spin injection device. The analysis showed that the so called dynamic nuclear polarization can be treated as a cooling tool for the nuclear spins: It works as a provider to exchange spin angular momentum between polarized electron spins and nuclear spins through the hyperfine interaction, leading to an increase in the nuclear polarization. In addition, a time-delay of the nuclear spin temperature with a fast sweep of the external magnetic field produces a possible transient state for the nuclear spin polarization. On the other hand, the nuclear magnetic resonance acts as a heating tool for a nuclear spin system. This causes the nuclear spin temperature to jump to infinity: i.e., the average nuclear spins along with the nuclear field vanish at resonant fields of 75As, 69Ga and 71Ga, showing an interesting step-dip structure in the oblique Hanle signals. These analyses provide a quantitative understanding of nuclear spin dynamics in semiconductors for application in future computation processing.
Analysis of the transient response of nuclear spins in GaAs with/without nuclear magnetic resonance
Directory of Open Access Journals (Sweden)
Mahmoud Rasly
2016-05-01
Full Text Available As an alternative to studying the steady-state responses of nuclear spins in solid state systems, working within a transient-state framework can reveal interesting phenomena. The response of nuclear spins in GaAs to a changing magnetic field was analyzed based on the time evolution of nuclear spin temperature. Simulation results well reproduced our experimental results for the transient oblique Hanle signals observed in an all-electrical spin injection device. The analysis showed that the so called dynamic nuclear polarization can be treated as a cooling tool for the nuclear spins: It works as a provider to exchange spin angular momentum between polarized electron spins and nuclear spins through the hyperfine interaction, leading to an increase in the nuclear polarization. In addition, a time-delay of the nuclear spin temperature with a fast sweep of the external magnetic field produces a possible transient state for the nuclear spin polarization. On the other hand, the nuclear magnetic resonance acts as a heating tool for a nuclear spin system. This causes the nuclear spin temperature to jump to infinity: i.e., the average nuclear spins along with the nuclear field vanish at resonant fields of 75As, 69Ga and 71Ga, showing an interesting step-dip structure in the oblique Hanle signals. These analyses provide a quantitative understanding of nuclear spin dynamics in semiconductors for application in future computation processing.
Quantum dot spin coherence governed by a strained nuclear environment
Stockill, R.; Le Gall, C.; Matthiesen, C.; Huthmacher, L.; Clarke, E.; Hugues, M.; Atatüre, M.
2016-01-01
The interaction between a confined electron and the nuclei of an optically active quantum dot provides a uniquely rich manifestation of the central spin problem. Coherent qubit control combines with an ultrafast spin–photon interface to make these confined spins attractive candidates for quantum optical networks. Reaching the full potential of spin coherence has been hindered by the lack of knowledge of the key irreversible environment dynamics. Through all-optical Hahn echo decoupling we now recover the intrinsic coherence time set by the interaction with the inhomogeneously strained nuclear bath. The high-frequency nuclear dynamics are directly imprinted on the electron spin coherence, resulting in a dramatic jump of coherence times from few tens of nanoseconds to the microsecond regime between 2 and 3 T magnetic field and an exponential decay of coherence at high fields. These results reveal spin coherence can be improved by applying large magnetic fields and reducing strain inhomogeneity. PMID:27615704
Bowers, C. Russell; Weitekamp, Daniel P.
1986-01-01
A method of obtaining very large nuclear-spin polarizations is proposed and illustrated by density-operator calculations. The prediction is that chemical reaction and rf irradiation can convert the scalar parahydrogen state into polarization of order unity on the nuclear spins of the products of molecular-hydrogen addition reactions. A means of extending the resultant sensitivity enhancement to other spins is proposed in which the transfer of order occurs through population differences not as...
Spin density matrices for nuclear density functionals with parity violations
Barrett, B R
2010-01-01
The spin density matrix (SDM) used in atomic and molecular physics is revisited for nuclear physics, in the context of the radial density functional theory. The vector part of the SDM defines a "hedgehog" situation, which exists only if nuclear states contain some amount of parity violation.
Nuclear Level Density at High Spin and Excitation Energy
Institute of Scientific and Technical Information of China (English)
A.N. Behkami; Z. Kargar
2001-01-01
The intensive studies of equilibrium processes in heavy-ion reaction have produced a need for information on nuclear level densities at high energies and spins. The Fermi gas level density is often used in investigation of heavy-ion reaction studies. Some papers have claimed that nuclear level densities might deviate substantially from the Fermi gas predications at excitations related to heavy-ion reactions. The formulae of calculation of the nuclear level density based on the theory of superconductivity are presented, special attention is paid to the dependence of the level density on the angular momentum. The spin-dependent nuclear level density is evaluated using the pairing interaction. The resulting level density for an average spin of 52h is evaluated for 155Er and compared with experimental data. Excellent agreement between experiment and theory is obtained.``
Statistical nuclear properties (level densities, spin distributions)
International Nuclear Information System (INIS)
A general overview is given on the phenomenological methods used to describe the level densities in nuclei. Two well-known two-parameter formulas of level densities, the Back-Shifted Fermi Gas (BSFG) model and the Constant Temperature (CT) model, were used. A common ingredient of both is the spin distribution function, which contains in Ericsons's parametrization the spin-cutoff parameter σ. A realistic description of the parameters of both spin distribution function and the two level density models has been obtained by fitting the experimental data of 310 nuclei between 18F and 251Cf, consisting of the complete level schemes at low excitation energies and the s-wave neutron resonance spacings at the neutron binding energy. We determine a simple formula for the spin-cutoff parameter as a function of mass number and excitation energy. Also, an even-odd spin staggering in the spin distribution of the even-even nuclei was observed, and described with a simple formula. Using this newly defined spin distribution function, an empirical set of parameters of the BSFG and CT models was determined by fitting both the low-energy levels and the neutron resonance spacings. For these parameters, simple formulas were proposed that involve only quantities available from the mass tables, and allow reasonable estimations of the level density parameters for nuclei far from stability. Both the BSFG and CT models describe equally well the level densities at energies up to at least the neutron binding energy. Finally, we discuss recent experimental evidence that the CT model is the more correct description of the nuclei in the low-excitation energy (pairing) regime.
Single shot NMR on single, dark nuclear spins
Waldherr, G; Steiner, M; Neumann, P; Gali, A; Jelezko, F; Wrachtrup, J
2010-01-01
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.
Tilted Foils Nuclear Spin Polarization at REX-ISOLDE
Törnqvist, Hans Toshihide
2013-08-08
This thesis will explain and summarize my work and involvement in experiments aimed at producing nuclear spin polarization of post-accelerated beams of ions with the tilted-foils technique at the REX-ISOLDE linear accelerator at CERN. Polarizing the nuclear spin of radioactive beams in particular may provide access to observables which may be difficult to obtain otherwise. Currently, the techniques commonly employed for nuclear spin polarization are restricted to specific nuclides and experimental measurement techniques. Tilted foils polarization may provide a new tool to extend the range of nuclides that can be polarized and the types of experiments that can be performed. The experiments rely not only on the production but also on the method to measure the degree of attained polarization. Two methods will be treated, based on particle scattering in Coulomb excitation that may be utilized for stable beams, and the $\\beta$-NMR that requires $\\beta$-decaying nuclei. The experimental setups and measurements will...
Theoretical aspects of Magic Angle Spinning - Dynamic Nuclear Polarization.
Mentink-Vigier, Frederic; Akbey, Ümit; Oschkinat, Hartmut; Vega, Shimon; Feintuch, Akiva
2015-09-01
Magic Angle Spinning (MAS) combined with Dynamic Nuclear Polarization (DNP) has been proven in recent years to be a very powerful method for increasing solid-state NMR signals. Since the advent of biradicals such as TOTAPOL to increase the nuclear polarization new classes of radicals, with larger molecular weight and/or different spin properties have been developed. These have led to unprecedented signal gain, with varying results for different experimental parameters, in particular the microwave irradiation strength, the static field, and the spinning frequency. Recently it has been demonstrated that sample spinning imposes DNP enhancement processes that differ from the active DNP mechanism in static samples as upon sample spinning the DNP enhancements are the results of energy level anticrossings occurring periodically during each rotor cycle. In this work we present experimental results with regards to the MAS frequency dependence of the DNP enhancement profiles of four nitroxide-based radicals at two different sets of temperature, 110 and 160K. In fact, different magnitudes of reduction in enhancement are observed with increasing spinning frequency. Our simulation code for calculating MAS-DNP powder enhancements of small model spin systems has been improved to extend our studies of the influence of the interaction and relaxation parameters on powder enhancements. To achieve a better understanding we simulated the spin dynamics of a single three-spin system {ea-eb-n} during its steady state rotor periods and used the Landau-Zener formula to characterize the influence of the different anti-crossings on the polarizations of the system and their necessary action for reaching steady state conditions together with spin relaxation processes. Based on these model calculations we demonstrate that the maximum steady state nuclear polarization cannot become larger than the maximum polarization difference between the two electrons during the steady state rotor cycle. This
Nuclear Tuning and Detuning of the Electron Spin Resonance in a Quantum Dot
Danon, Jeroen; Nazarov, Yuli V.
2007-01-01
We study nuclear spin dynamics in a quantum dot close to the conditions of electron spin resonance. We show that at small frequency mismatch the nuclear field detunes the resonance. Remarkably, at larger frequency mismatch its effect is opposite: The nuclear system is bistable, and in one of the stable states the field accurately tunes the electron spin splitting to resonance. In this state the nuclear field fluctuations are strongly suppressed and nuclear spin relaxation is accelerated.
Coherent manipulation of nuclear spins in the breakdown regime of integer quantum Hall states
Kawamura, Minoru; Takahashi, Hiroyuki; Hashimoto, Yoshiaki; Katsumoto, Shingo; Machida, Tomoki
2008-01-01
We demonstrate a new method for electrical manipulation of nuclear spins utilizing dynamic nuclear polarization induced by quantum Hall effect breakdown. Nuclear spins are polarized and detected through the hyperfine interaction between a nuclear spin system and a two-dimensional electron system located at an interface of GaAs/AlGaAs single heterostructure. Coherent oscillations between the nuclear-spin quantum states are observed by measuring the longitudinal voltage of the conductor.
Danon, J.; Nazarov, Y. V.
2008-01-01
We study nuclear spin dynamics in a quantum dot close to the conditions of electron spin resonance. We show that at a small frequency mismatch, the nuclear field detunes the resonance. Remarkably, at larger frequency mismatch, its effect is opposite: The nuclear system is bistable, and in one of the stable states, the field accurately tunes the electron spin splitting to resonance. In this state, the nuclear field fluctuations are strongly suppressed, and nuclear spin relaxation is accelerated.
DEFF Research Database (Denmark)
Kirpekar, Sheela; Jensen, Hans Jørgen Aagaard; Oddershede, Jens
1997-01-01
Using the quadratic response function at the ab initio SCF level of approximation we have calculated the relativistic corrections from the spin-orbit Hamiltonian, HSO, to the indirect nuclear spin-spin coupling constants of XH4 (X = C, Si, Ge, and Sn). We find that the spin-orbit contributions to...
Generating highly polarized nuclear spins in solution using dynamic nuclear polarization
DEFF Research Database (Denmark)
Wolber, J.; Ellner, F.; Fridlund, B.;
2004-01-01
and other low-γ nuclei. Subsequent to the DNP process, the solid sample is dissolved rapidly with a warm solvent to create a solution of molecules with highly polarized nuclear spins. Two main applications are proposed: high-resolution liquid state NMR with enhanced sensitivity, and the use......A method to generate strongly polarized nuclear spins in solution has been developed, using Dynamic Nuclear Polarization (DNP) at a temperature of 1.2K, and at a field of 3.354T, corresponding to an electron spin resonance frequency of 94GHz. Trityl radicals are used to directly polarize 13C...
Experiments with Exotic Spin-Oriented Nuclear Beams and Examples of Nuclear Moment Measurements
Balabanski, D. L.; Neyens, G.; Borremans, D.; Coulier, N.; Daugas, J. M.; Teughels, S.; Georgiev, G.; Lewitowicz, M.; de Oliveira Santos, F.; Penionzhkevich, Yu. E.
2002-04-01
An overview of a series of recent experiments aimed at the determination of the moments of exotic nuclei is presented. The spin-orientation: spin-alignment and spin-polarization of the nuclear ensemble, which is produced in fragmentation reactions, is of utmost importance for these studies. The discussion emphasizes on the open problems related to the production and the preservation of the orientation during the experiments. Pros and contras for experiments at both, intermediate and high energies are considered. Examples from nuclear moment measurements, which were performed using the LISE-III spectrometer at GANIL, are provided. The spin-alignment and the spin-polarization of the nuclear ensemble were studied by the β-LMR, β-NMR and TDPAD experimental techniques. The experimental results are discussed in the framework of the kinematical model of the fragmentation reaction.
Quantum computation with nuclear spins in quantum dots
Christ, Henning
2008-01-01
In this thesis we present protocols for the polarization of nuclear spins in a quantum dot via the hyperfine interaction with a conduction band electron and give a quantitative solution to the master equation we derive. The collective interference effects limiting the polarization are studied in detail, and ways of mitigating them are proposed. At high polarization levels the electron-nuclear interaction is approximated with simple and practical (quantum optical) models, suggesting the possib...
Hu, H; Hu, Huping; Wu, Maoxin
2002-01-01
We postulate that consciousness is connected to quantum mechanical spin since said spin is embedded in the microscopic structure of spacetime and may be more fundamental than spacetime itself. Thus, we theorize that consciousness is connected with the fabric of spacetime through spin. That is, spin is the "pixel" and "antenna" of mind. The unity of mind is achieved by non-local means within the pre-spacetime domain interfaced with spacetime. Human mind is possible because of the particular structures and dynamics of our brain postulated working as follows: The unpaired electronic spins of highly lipid-soluble and rapidly diffusing oxygen molecules extract information from the dynamical neural membranes and communicate said information through strong spin-spin couplings to the nuclear spin ensemble in the membranes for consciousness-related quantum statistical processing which survives decoherence. In turn, the dynamics of the nuclear spin ensemble has effects through spin chemistry on the classical neural act...
Dzhioev, R. I.; Korenev, V. L.
2007-01-01
Nuclear quadrupole interaction extends the limits imposed by hyperfine interaction on the spin coherence of the electron and nuclei in a quantum dot. The strain-induced nuclear quadrupole interaction suppresses the nuclear spin flip and makes possible the zero-field dynamic nuclear polarization in self-organized InP/InGaP quantum dots. The direction of the effective nuclear magnetic field is fixed in space, thus quenching the magnetic depolarization of the electron spin in the quantum dot. Th...
Chekhovich, E. A.; Hopkinson, M.; Skolnick, M. S.; Tartakovskii, A. I.
2015-01-01
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 rep...
Squeezing and entangling nuclear spins in helium 3
DEFF Research Database (Denmark)
Reinaudi, Gael; Sinatra, Alice; Dantan, Aurelien Romain;
2007-01-01
We present a realistic model for transferring the squeezing or the entanglement of optical field modes to the collective ground state nuclear spin of 3He using metastability exchange collisions. We discuss in detail the requirements for obtaining good quantum state transfer efficiency and study t...
Hanle effect in (In,Ga)As quantum dots: Role of nuclear spin fluctuations
Kuznetsova, M. S.; Flisinski, K.; Gerlovin, I. Ya.; Ignatiev, I. V.; Kavokin, K. V.; Verbin, S. Yu.; Yakovlev, D. R.; Reuter, D; Wieck, A. D.; Bayer, M.
2013-01-01
The role of nuclear spin fluctuations in the dynamic polarization of nuclear spins by electrons is investigated in (In,Ga)As quantum dots. The photoluminescence polarization under circularly polarized optical pumping in transverse magnetic fields (Hanle effect) is studied. A weak additional magnetic field parallel to the optical axis is used to control the efficiency of nuclear spin cooling and the sign of nuclear spin temperature. The shape of the Hanle curve is drastically modified with cha...
Long-term Dynamics of the Electron-nuclear Spin System of a Semiconductor Quantum Dot
Merkulov, I. A.; Alvarez, G; Yakovlev, D. R.; Schulthess, T. C.
2009-01-01
A quasi-classical theoretical description of polarization and relaxation of nuclear spins in a quantum dot with one resident electron is developed for arbitrary mechanisms of electron spin polarization. The dependence of the electron-nuclear spin dynamics on the correlation time $\\tau_c$ of electron spin precession, with frequency $\\Omega$, in the nuclear hyperfine field is analyzed. It is demonstrated that the highest nuclear polarization is achieved for a correlation time close to the perio...
Chekhovich, E. A.; Hopkinson, M.; Skolnick, M. S.; Tartakovskii, A. I.
2015-01-01
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 rep...
Chow, Colin M.; Ross, Aaron M.; Kim, Danny; Gammon, Daniel; Bracker, Allan S.; Sham, L. J.; Steel, Duncan G.
2016-08-01
We demonstrate the extension of coherence between all four two-electron spin ground states of an InAs quantum dot molecule (QDM) via nonlocal suppression of nuclear spin fluctuations in two vertically stacked quantum dots (QDs), while optically addressing only the top QD transitions. Long coherence times are revealed through dark-state spectroscopy as resulting from nuclear spin locking mediated by the exchange interaction between the QDs. Line shape analysis provides the first measurement of the quieting of the Overhauser field distribution correlating with reduced nuclear spin fluctuations.
Chow, Colin M; Ross, Aaron M; Kim, Danny; Gammon, Daniel; Bracker, Allan S; Sham, L J; Steel, Duncan G
2016-08-12
We demonstrate the extension of coherence between all four two-electron spin ground states of an InAs quantum dot molecule (QDM) via nonlocal suppression of nuclear spin fluctuations in two vertically stacked quantum dots (QDs), while optically addressing only the top QD transitions. Long coherence times are revealed through dark-state spectroscopy as resulting from nuclear spin locking mediated by the exchange interaction between the QDs. Line shape analysis provides the first measurement of the quieting of the Overhauser field distribution correlating with reduced nuclear spin fluctuations. PMID:27563998
Tilted Foils Nuclear Spin Polarization and Measurement with Coulomb Excitation
Törnqvist, Hans; Kowalska, M; Wenander, F
2012-01-01
Developing new experimental tools is essential to expand the possibilities of probing the structure of atomic nuclei. The better the currently known properties of nuclei can be manipulated, the more information can be extracted from data collected in nuclear reaction experiments. One property that has been controlled for many years is the nuclear spin, but this has only been viable for a certain set of isotopes with restrictions on for example specific atomic excitation schemes or half-lives. This thesis will provide details on an evaluation project using thin tilted foils after the REX-ISOLDE linac at the CERN-ISOLDE experimental facility, to polarize the spin of nuclei in-flight. The nuclear polarization is then measured with a technique based on Coulomb excitation, which is a flexible and readily available experimental method at ISOLDE with the MINIBALL spectrometer. The tilted foils technique may be beneficial to polarize the nuclear spin of short-lived radioactive beams that can be difficult by other mea...
Nuclear spin relaxation due to random motion of vortex bundles
International Nuclear Information System (INIS)
The dependence of nuclear-spin-relaxation rate T1 on NMR resonant frequency for a layered superconducting sample has been analyzed theoretically. In the considered arrangement the Zeeman field has been applied in the plane of superconducting layers while the relaxation was due to interactions between the spin systems and moving flux bundles, created by the transport current flowing along superconducting layers. It has been found that the functional form of a dependence of spin-relaxation rate on the Zeeman field has two components, a Lorentzian and an oscillatory one. The characteristic rolloff frequency of the Lorentzian component depends on the pinning properties of the sample. The period of oscillations of the oscillatory component is of the order of the inverse of interaction time of flowing flux bundles with a probe nucleus. copyright 1996 The American Physical Society
Nuclear structure of 216Ra at high spin
Indian Academy of Sciences (India)
S Muralithar; G Rodrigues; R P Singh; R K Bhowmik; P Mukherjee; B Sethi; I Mukherjee
2012-09-01
High-spin states of 216Ra ( = 88, = 128) have been investigated through 209Bi(10B, 3n) reaction at an incident beam energy of 55 MeV and 209Bi(11B, 4n) reaction at incident beam energies ranging from 65 to 78 MeV. Based on coincidence data, the level scheme for 216Ra has been considerably extended up to $∼ 33\\hbar$ spin and 7.2 MeV excitation energy in the present experiment with placement of 28 new -transitions over what has been reported earlier. Tentative spin-parity assignments are done for the newly proposed levels on the basis of the DCO ratios corresponding to strong gates. Empirical shell model calculations were carried out to provide an understanding of the underlying nuclear structure.
Nuclear spin response studies in inelastic polarized proton scattering
International Nuclear Information System (INIS)
Spin-flip probabilities S/sub nn/ have been measured for inelastic proton scattering at incident proton energies around 300 MeV from a number of nuclei. At low excitation energies S/sub nn/ is below the free value. For excitation energies above about 30 MeV for momentum transfers between about 0.35 fm/sup /minus/1/ and 0.65 fm/sup / minus/1/ S/sub nn/ exceeds free values significantly. These results suggest that the relative ΔS = 1(ΔS = 0 + ΔS = 1) nuclear spin response approaches about 90% in the region of the enhancement. Comparison of the data with slab response calculations are presented. Decomposition of the measured cross sections into σ(ΔS = 0) and σ(ΔS = 1) permit extraction of nonspin-flip and spin-flip dipole and quadrupole strengths. 29 refs., 11 figs
Electrical polarization of nuclear spins in a breakdown regime of quantum Hall effect
Kawamura, M.; Takahashi, H; Sugihara, K; Masubuchi, S.; Hamaya, K.; Machida, T.
2006-01-01
We have developed a method for electrical polarization of nuclear spins in quantum Hall systems. In a breakdown regime of odd-integer quantum Hall effect (QHE), excitation of electrons to the upper Landau subband with opposite spin polarity dynamically polarizes nuclear spins through the hyperfine interaction. The polarized nuclear spins in turn accelerate the QHE breakdown, leading to hysteretic voltage-current characteristics of the quantum Hall conductor.
Nuclear spin relaxation in liquids theory, experiments, and applications
Kowalewski, Jozef
2006-01-01
Nuclear magnetic resonance (NMR) is widely used across many fields because of the rich data it produces, and some of the most valuable data come from the study of nuclear spin relaxation in solution. While described to varying degrees in all major NMR books, spin relaxation is often perceived as a difficult, if not obscure, topic, and an accessible, cohesive treatment has been nearly impossible to find.Collecting relaxation theory, experimental techniques, and illustrative applications into a single volume, this book clarifies the nature of the phenomenon, shows how to study it, and explains why such studies are worthwhile. Coverage ranges from basic to rigorous theory and from simple to sophisticated experimental methods, and the level of detail is somewhat greater than most other NMR texts. Topics include cross-relaxation, multispin phenomena, relaxation studies of molecular dynamics and structure, and special topics such as relaxation in systems with quadrupolar nuclei and paramagnetic systems.Avoiding ove...
Resistive detection of nuclear spins in a single quantum dot under Kondo effect regime
Kawamura, Minoru; Gottwald, Daniel; Ono, Keiji; Machida, Tomoki; Kono, Kimitoshi
2013-01-01
We study dynamic polarization and resistive detection of nuclear spins in a semiconductor quantum dot (QD) under the Kondo effect regime. We find that the differential conductance spectra of the QD exhibit hysteresis under the Kondo effect regime in magnetic fields. Relevance of nuclear spins to the hysteresis is confirmed by the detection of nuclear magnetic resonance signals by monitoring the differential conductance. We attribute the origin of the hysteresis to the dynamic nuclear spin pol...
Solid effect in magic angle spinning dynamic nuclear polarization
Corzilius, Björn; Smith, Albert A.; Griffin, Robert G.
2012-08-01
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 ω _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 ɛ = 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.
129Xe EDM Search Experiment Using Active Nuclear Spin Maser
Sato, Tomoya; Ichikawa, Yuichi; Ohtomo, Yuichi; Sakamoto, Yu; Kojima, Shuichiro; Suzuki, Takahiro; Shirai, Hazuki; Chikamori, Masatoshi; Hikota, Eri; Miyatake, Hirokazu; Nanao, Tsubasa; Suzuki, Kunifumi; Tsuchiya, Masato; Inoue, Takeshi; Furukawa, Takeshi; Yoshimi, Akihiro; Bidinosti, Christopher P.; Ino, Takashi; Ueno, Hideki; Matsuo, Yukari; Fukuyama, Takeshi; Asahi, Koichiro
An active nuclear spin maser, which enables a precision measurement of spin precession frequency, is employed in the experimental search for permanent electric dipole moment (EDM) in the diamagnetic atom 129Xe. In order to eliminate systematic errors which limit the sensitivity of the experiment to an EDM, the following tactics are adopted: (i) 3He comagnetometry for the cancellation of long-term drifts in the external magnetic fields and (ii) double-cell geometry for the mitigation of frequency shifts due to interaction of 129Xe spin with polarized Rb atoms. In the present work, the design for the double-cell has been changed and a magnetic shield-coil system to provide a highly homogeneous magnetic field has been newly introduced. Thanks to increased polarization and longer 3He spin relaxation time, the dual-species maser of 129Xe and 3He in a double-cell geometry operated successfully. Our experiment is now at the stage of assembling these separate technical elements in order to start the measurement of 129Xe EDM in the 10-28 ecm region.
Voltage induced conversion of helical to uniform nuclear spin polarization in a quantum wire
Kornich, Viktoriia; Stano, Peter; Zyuzin, Alexander A.; Loss, Daniel
2015-01-01
We study the effect of bias voltage on the nuclear spin polarization of a ballistic wire, which contains electrons and nuclei interacting via hyperfine interaction. In equilibrium, the localized nuclear spins are helically polarized due to the electron-mediated Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. Focusing here on non-equilibrium, we find that an applied bias voltage induces a uniform polarization, from both helically polarized and unpolarized spins available for spin flips. Once...
Nuclear Spin Maser at Highly Stabilized Low Magnetic Field and Search for Atomic EDM
International Nuclear Information System (INIS)
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.
Nuclear Hydrogen for Peak Electricity Production and Spinning Reserve
Energy Technology Data Exchange (ETDEWEB)
Forsberg, C.W.
2005-01-20
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
Danon, J.; Nazarov, Y.V.
2008-01-01
We study nuclear spin dynamics in a quantum dot close to the conditions of electron spin resonance. We show that at a small frequency mismatch, the nuclear field detunes the resonance. Remarkably, at larger frequency mismatch, its effect is opposite: The nuclear system is bistable, and in one of the
Persistent optical nuclear spin narrowing in a singly charged InAs quantum dot
W. Yao; Sun, B.; Xu, X.; Bracker, AS; Gammon, D.; Sham, LJ; Steel, D.
2012-01-01
We review the investigation of the hole-assisted dynamical nuclear spin polarization mechanism in a singly charged InAs quantum dot. Using coherent dark state spectroscopy, we measure the locking of the Overhauser field to a value determined only by the laser frequencies. Importantly, we review data that the locking effect can suppress nuclear spin fluctuations. We determine the onset time of the nuclear spin narrowing effect and its persistence absent laser interactions by directly measuring...
Radioactive nuclear beams and the North American IsoSpin Laboratory (ISL) initiative
International Nuclear Information System (INIS)
Radioactive nuclear beams (RNBs) offer exciting new research opportunities in fields as diverse as nuclear structure, nuclear reactions, astrophysics atomic, materials, and applied science. Their realization in new accelerator complexes also offers important technical challenges. Some of the nuclear physics possibilities afforded by RNBs, with emphasis on low spin nuclear structure, are discussed, accompanied by an outline of the ISL initiative and its status
A 3D-printed high power nuclear spin polarizer.
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
2014-01-29
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 (129)Xe and (1)H nuclear spins), (ii) 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 (129)Xe 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 (129)Xe polarization exponential build-up rate [(3.63 ± 0.15) × 10(-2) min(-1)] and in-cell (129)Xe 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 (129)Xe and Rb (PRb ∼ 96%). Hyperpolarization-enhanced (129)Xe 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.
Quantum information processing with electronic and nuclear spins in semiconductors
Klimov, Paul Victor
Traditional electronic and communication devices operate by processing binary information encoded as bits. Such digital devices have led to the most advanced technologies that we encounter in our everyday lives and they influence virtually every aspect of our society. Nonetheless, there exists a much richer way to encode and process information. By encoding information in quantum mechanical states as qubits, phenomena such as coherence and entanglement can be harnessed to execute tasks that are intractable to digital devices. Under this paradigm, it should be possible to realize quantum computers, quantum communication networks and quantum sensors that outperform their classical counterparts. The electronic spin states of color-center defects in the semiconductor silicon carbide have recently emerged as promising qubit candidates. They have long-lived quantum coherence up to room temperature, they can be controlled with mature magnetic resonance techniques, and they have a built-in optical interface operating near the telecommunication bands. In this thesis I will present two of our contributions to this field. The first is the electric-field control of electron spin qubits. This development lays foundation for quantum electronics that operate via electrical gating, much like traditional electronics. The second is the universal control and entanglement of electron and nuclear spin qubits in an ensemble under ambient conditions. This development lays foundation for quantum devices that have a built-in redundancy and can operate in real-world conditions. Both developments represent important steps towards practical quantum devices in an electronic grade material.
Rao, K. Rama Koteswara; Suter, Dieter
2016-08-01
The nitrogen-vacancy (NV) center in diamond has attractive properties for a number of quantum technologies that rely on the spin angular momentum of the electron and the nuclei adjacent to the center. The nucleus with the strongest interaction is the 13C nuclear spin of the first shell. Using this degree of freedom effectively hinges on precise data on the hyperfine interaction between the electronic and the nuclear spin. Here, we present detailed experimental data on this interaction, together with an analysis that yields all parameters of the hyperfine tensor, as well as its orientation with respect to the atomic structure of the center.
Institute of Scientific and Technical Information of China (English)
Hu Xin; Liu Dong-Qi; Pan Xin-Yu
2011-01-01
A collapse and revival shape of Rabi oscillations in an electron spin of a single nitrogen-vacancy centre has been observed in diamond at room temperature.Because of hyperfine interaction between the host 14N nuclear spin and the nitrogen-vacancy centre electron spin,different orientations of the 14N nuclear spins lead to a triplet splitting of the transition between ground state (ms =0) and excited state (ms =1).The manipulation of the single electron spin of nitrogen-vacancy centre is achieved by using a combination of selective microwave excitation and optical pumping at 532 nm.Microwaves can excite three transitions equally to induce three independent nutations and the shape of Rabi oscillations is a combination of the three nutations.
Toward higher nuclearity: tetranuclear cobalt(II) metallogrid exhibiting spin crossover.
Wu, Shu-Qi; Wang, Yi-Tong; Cui, Ai-Li; Kou, Hui-Zhong
2014-03-01
Supramolecular strategy was employed to achieve the highest nuclearity Co(II) cluster exhibiting spin-crossover (SCO) behavior. Magnetic susceptibility characterization of the Co4(II) complex shows that two different spin-transition processes occur. The SCO behavior is directed by the partially deprotonated polydentate ligand, which favors the structural distortion required by the spin transition. PMID:24555696
Large-scale cluster state generation with nuclear spins in diamonds
International Nuclear Information System (INIS)
The cluster state is an indispensable resource for one-way quantum computing (1WQC). We propose a practical scheme for constructing cluster states among nuclear spins in nitrogen-vacancy defect centres (NV centres) in different diamonds. The entanglement of nuclear spins within an NV centre is made by hyperfine coupling via electron spin, and the entanglement between remote NV centres is accomplished using the parity projection of emitted photons. We discus the possibility to build large-scale nuclear-spin cluster states with diamonds. (general)
Robust Quantum-Network Memory Using Decoherence-Protected Subspaces of Nuclear Spins
Reiserer, Andreas; Kalb, Norbert; Blok, Machiel S.; van Bemmelen, Koen J. M.; Taminiau, Tim H.; Hanson, Ronald; Twitchen, Daniel J.; Markham, Matthew
2016-04-01
The realization of a network of quantum registers is an outstanding challenge in quantum science and technology. We experimentally investigate a network node that consists of a single nitrogen-vacancy center electronic spin hyperfine coupled to nearby nuclear spins. We demonstrate individual control and readout of five nuclear spin qubits within one node. We then characterize the storage of quantum superpositions in individual nuclear spins under repeated application of a probabilistic optical internode entangling protocol. We find that the storage fidelity is limited by dephasing during the electronic spin reset after failed attempts. By encoding quantum states into a decoherence-protected subspace of two nuclear spins, we show that quantum coherence can be maintained for over 1000 repetitions of the remote entangling protocol. These results and insights pave the way towards remote entanglement purification and the realization of a quantum repeater using nitrogen-vacancy center quantum-network nodes.
Three-body Effect on Equation of State of Spin-polarized Nuclear Matter
Institute of Scientific and Technical Information of China (English)
ZuoWei
2003-01-01
The equation of state (EOS) of spin-polarized nuclear matter has been investigated within the spin-dependent; Brueckner-Hartree-Fock framework by adopting the realistic nucleon-nucleon interaction supplemented with a microscopic three-body force. The three-body force effects have been studied and stressed with a special attention. The calculated results are given in Fig.1. It is seen that; in the Brueckner-Hartree-Fock framework the predicted energy per particle of spin-polarized nuclear matter versus the neutron and proton spin-polarization parameters fulfills a quadratic law in the whole range of spin-polarization. The related physical quantities such as spin the Landau parameters Go in spin channel and G′0 in spin-isospin channel, have been also calculated.
Coherent manipulation of an NV center and one carbon nuclear spin
Energy Technology Data Exchange (ETDEWEB)
Scharfenberger, Burkhard; Nemoto, Kae [National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430 (Japan); Munro, William J. [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan)
2014-12-04
We study a three-qubit system formed by the NV center’s electronic and nuclear spin plus an adjacent spin 1/2 carbon {sup 13}C. 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.
High-fidelity readout and control of a nuclear spin qubit in silicon.
Pla, Jarryd J; Tan, Kuan Y; Dehollain, Juan P; Lim, Wee H; Morton, John J L; Zwanenburg, Floris A; Jamieson, David N; Dzurak, Andrew S; Morello, Andrea
2013-04-18
Detection of nuclear spin precession is critical for a wide range of scientific techniques that have applications in diverse fields including analytical chemistry, materials science, medicine and biology. Fundamentally, it is possible because of the extreme isolation of nuclear spins from their environment. This isolation also makes single nuclear spins desirable for quantum-information processing, as shown by pioneering studies on nitrogen-vacancy centres in diamond. The nuclear spin of a (31)P donor in silicon is very promising as a quantum bit: bulk measurements indicate that it has excellent coherence times and silicon is the dominant material in the microelectronics industry. Here we demonstrate electrical detection and coherent manipulation of a single (31)P nuclear spin qubit with sufficiently high fidelities for fault-tolerant quantum computing. By integrating single-shot readout of the electron spin with on-chip electron spin resonance, we demonstrate quantum non-demolition and electrical single-shot readout of the nuclear spin with a readout fidelity higher than 99.8 percent-the highest so far reported for any solid-state qubit. The single nuclear spin is then operated as a qubit by applying coherent radio-frequency pulses. For an ionized (31)P donor, we find a nuclear spin coherence time of 60 milliseconds and a one-qubit gate control fidelity exceeding 98 percent. These results demonstrate that the dominant technology of modern electronics can be adapted to host a complete electrical measurement and control platform for nuclear-spin-based quantum-information processing. PMID:23598342
Antiferromagnetic nuclear spin helix and topological superconductivity in 13C nanotubes
Hsu, Chen-Hsuan; Stano, Peter; Klinovaja, Jelena; Loss, Daniel
2015-12-01
We investigate the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction arising from the hyperfine coupling between localized nuclear spins and conduction electrons in interacting 13C carbon nanotubes. Using the Luttinger liquid formalism, we show that the RKKY interaction is sublattice dependent, consistent with the spin susceptibility calculation in noninteracting carbon nanotubes, and it leads to an antiferromagnetic nuclear spin helix in finite-size systems. The transition temperature reaches up to tens of mK, due to a strong boost by a positive feedback through the Overhauser field from ordered nuclear spins. Similar to GaAs nanowires, the formation of the helical nuclear spin order gaps out half of the conduction electrons, and is therefore observable as a reduction of conductance by a factor of 2 in a transport experiment. The nuclear spin helix leads to a density wave combining spin and charge degrees of freedom in the electron subsystem, resulting in synthetic spin-orbit interaction, which induces nontrivial topological phases. As a result, topological superconductivity with Majorana fermion bound states can be realized in the system in the presence of proximity-induced superconductivity without the need of fine tuning the chemical potential. We present the phase diagram as a function of system parameters, including the pairing gaps, the gap due to the nuclear spin helix, and the Zeeman field perpendicular to the helical plane.
Stable three-axis nuclear-spin gyroscope in diamond
Ajoy, Ashok; Cappellaro, Paola
2012-12-01
Gyroscopes find wide applications in everyday life from navigation and inertial sensing to rotation sensors in hand-held devices and automobiles. Current devices, based on either atomic or solid-state systems, impose a choice between long-time stability and high sensitivity in a miniaturized system. Here, we introduce a quantum sensor that overcomes these limitations by providing a sensitive and stable three-axis gyroscope in the solid state. We achieve high sensitivity by exploiting the long coherence time of the 14N nuclear spin associated with the nitrogen-vacancy center in diamond, combined with the efficient polarization and measurement of its electronic spin. Although the gyroscope is based on a simple Ramsey interferometry scheme, we use coherent control of the quantum sensor to improve its coherence time and robustness against long-time drifts. Such a sensor can achieve a sensitivity of η˜0.5(mdegs-1)/Hzmm3 while offering enhanced stability in a small footprint. 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.
Nuclear spin scissors – new type of collective motion
International Nuclear Information System (INIS)
The coupled dynamics of the orbital and spin scissors modes is studied with the help of the Wigner Function Moments method on the basis of Time Dependent Hartree-Fock equations in the harmonic oscillator model including spin orbit potential plus quadrupole- quadrupole and spin-spin residual interactions. The relation between our results and the recent experimental data is discussed.
Pumping dynamics of nuclear spins in GaAs quantum wells
Mocek, Raphael W; Cascio, Giovanni; Suter, Dieter
2016-01-01
Irradiating a semiconductor with circularly polarized light creates spin-polarized charge carriers. If the material contains atoms with non-zero nuclear spin, they interact with the electron spins via the hyperfine coupling. Here, we consider GaAs/AlGaAs quantum wells, where the conduction-band electron spins interact with three different types of nuclear spins. The hyperfine interaction drives a transfer of spin polarization to the nuclear spins, which therefore acquire a polarization that is comparable to that of the electron spins. In this paper, we analyze the dynamics of the optical pumping process in the presence of an external magnetic field while irradiating a single quantum well with a circularly polarized laser. We measure the time dependence of the photoluminescence polarization to monitor the buildup of the nuclear spin polarization and thus the average hyperfine interaction acting on the electron spins. We present a simple model that adequately describes the dynamics of this process and is in goo...
Schuetz, M. J. A.; Kessler, E. M.; Vandersypen, L. M. K.; Cirac, J. I.; Giedke, G.
2014-01-01
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 ...
Influence of spin polarizability on liquid gas phase transition in the nuclear matter
Rezaei, Z; Bordbar, G H
2015-01-01
In this paper, we investigate the liquid gas phase transition for the spin polarized nuclear matter. Applying the lowest order constrained variational (LOCV) method, and using two microscopic potentials, $AV_{18}$ and $UV_{14}$+TNI, we calculate the free energy, equation of state, order parameter, entropy, heat capacity and compressibility to derive the critical properties of spin polarized nuclear matter. Our results indicate that for the spin polarized nuclear matter, the second order phase transition takes place at lower temperatures with respect to the unpolarized one. It is also shown that the critical temperature of our spin polarized nuclear matter with a specific value of spin polarization parameter is in good agreement with the experimental result.
Quantum state transfer between an optomechanical cavity and a diamond nuclear spin ensemble
Feng, Zhi-Bo; Wang, Hong-Ling; Yan, Run-Ying
2016-08-01
We explore an efficient scheme for transferring quantum state between an optomechanical cavity and nuclear spins of nitrogen-vacancy centers in diamond, where quantum information can be efficiently stored (retrieved) into (from) the nuclear spin ensemble assisted by a mechanical resonator in a dispersive regime. Our scheme works for a broad range of cavity frequencies and might have potential applications in employing the nuclear spin ensemble as a memory in quantum information processing. The feasibility of our protocol is analyzed using currently available parameters.
Photoinduced nuclear spin conversion of methyl groups of single molecules
International Nuclear Information System (INIS)
A methyl group is an outstanding quantum system due to its special symmetry properties. The threefold rotation around one of its bond is isomorphic to the group of even permutations of the remaining protons, a property which imposes severe quantum restrictions on the system, for instance a strict correlation of rotational states with nuclear spin states. The resulting long lifetimes of the rotational tunneling states of the methyl group can be exploited for applying certain high resolution optical techniques, like hole burning or single molecule spectroscopy to optically switch the methyl group from one tunneling state to another therebye changing the nuclear spin of the protons. One goal of the thesis was to perform this switching in single methyl groups. To this end the methyl group was attached to a chromophoric system, in the present case terrylene, which is well suited for single molecule spectroscopy as well as for hole burning. Experiments were performed with the bare terrylene molecule in a hexadecane lattice which served as a reference system, with alphamethyl terrylene and betamethyl terrylene, both embedded in hexadecane, too. A single molecular probe is a highly sensitive detector for dynamic lattice instabilities. Already the bare terrylene probe showed a wealth of interesting local dynamic effects of the hexadecane lattice which could be well acounted for by the assumption of two nearly degenerate sites with rather different optical and thermal properties, all of which could be determined in a quantitative fashion. As to the methylated terrylene systems, the experiments verified that for betamethyl terrylene it is indeed possible to measure rotational tunneling events in single methyl groups. However, the spectral patterns obtained was much more complicated than expected pointing to the presence of three spectroscopically different methyl groups. In order to achieve a definite assignement, molecular mechanics simulations of the terrylene probes in the
Qubit Control Limited by Spin-Lattice Relaxation in a Nuclear Spin-Free Iron(III) Complex.
Zadrozny, Joseph M; Freedman, Danna E
2015-12-21
High-spin transition metal complexes are of interest as candidates for quantum information processing owing to the tunability of the pairs of MS levels for use as quantum bits (qubits). Thus, the design of high-spin systems that afford qubits with stable superposition states is of primary importance. Nuclear spins are a potent instigator of superposition instability; thus, we probed the Ph4P(+) salt of the nuclear spin-free complex [Fe(C5O5)3](3-) (1) to see if long-lived superpositions were possible in such a system. Continuous-wave and pulsed electron paramagnetic resonance (EPR) spectroscopic measurements reveal a strong EPR transition at X-band that can be utilized as a qubit. However, at 5 K the coherent lifetime, T2, for this resonance is 721(3) ns and decreases rapidly with increasing temperature. Simultaneously, the spin-lattice relaxation time is extremely short, 11.33(1) μs, at 5 K, and also rapidly decreases with increasing temperature. The coincidence of these two temperature-dependent data sets suggests that T2 in 1 is strongly limited by the short T1. Importantly, these results highlight the need for new design parameters in pursuit of high-spin species with appreciable coherence times. PMID:26650962
Jiang, Li; Zhang, Guo-Feng
2016-08-01
The effects of nuclear field and spin-orbit interaction on dense coding and swap operation are studied in detail for both the antiferromagnetic (AFM) and ferromagnetic (FM) coupling cases. The conditions for a valid dense coding and under which swap operation is feasible are given.
Noise-resilient Quantum Computing with a Nitrogen-Vacancy Center and Nuclear Spins
Casanova, J.; Wang, Z. -Y.; Plenio, M. B.
2016-01-01
Selective control of qubits in a quantum register for the purposes of quantum information processing represents a critical challenge for dense spin ensembles in solid state systems. Here we present a protocol that achieves a complete set of selective single and two-qubit gates on nuclear spins in such an ensemble in diamond facilitated by a nearby NV center. The protocol suppresses internuclear interactions as well as unwanted coupling between the NV center and other spins of the ensemble to ...
Nuclear magnetic moments and the spin-orbit current in the relativistic mean field theory
International Nuclear Information System (INIS)
The Dirac magnetic moments in the relativistic mean field theory are affected not only by the effective mass, but also by the spin-orbit current related to the spin-orbit force through the continuity equation. Previous arguments on the cancellation of the effective-mass effect in nuclear matter are not simply applied to finite nuclei to obtain the Schmidt values. Effects of the spin-orbit current on (e, e') response functions are also mentioned. (orig.)
Interaction of the nuclear spin with the degenerate vibration of a molecule
International Nuclear Information System (INIS)
The contributions of the nuclear motion and the spin-orbit coupling to the total interaction of the proton spin in H+3 and the deuteron spin in D+3 with the circularly polarized degenerate bending vibration are calculated. Their values are found to be Cnucl = -33.645 kHz, Cso = -19.251 kHz for the proton in the H+3 and Cnucl = -2.550 kHz, Cso = -0.794 kHz for the deuteron in the D+3. Within the framework of the model of the rigid nonvibrating molecule, the estimates of similar contributions to the total interaction of the nuclear spin with the rotation of a molecule are Cnucl = 64.610 kHz, Cso = -0.006 kHz for the H+3 and Cnucl = 4.961 kHz, Cso = -0.0001 kHz for D+3. The physical reasons for the opposite signs of the constants Cnucl for the nuclear spin-vibration interaction and spin-rotation interaction, as well as the cause of the abrupt increase of the spin-orbit contribution Cso to interaction of the nuclear spin with the circularly polarized bending vibration in comparison to the similar contribution to the nuclear spin-rotation interaction, are discussed. The results obtained in this paper may be used as a starting point for experimentally studying the interaction of the nuclear spin with the circularly polarized bending vibration of a molecule. 16 refs., 2 figs., 1 tab
Energy Technology Data Exchange (ETDEWEB)
Cho, Herman M.; Washton, Nancy M.; Mueller, Karl T.; Sears, Jr., Jesse A.; Townsend, Mark R.; Ewing, James R.
2016-06-14
A magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) probe is described that includes double containment enclosures configured to seal and contain hazardous samples for analysis. The probe is of a modular design that ensures containment of hazardous samples during sample analysis while preserving spin speeds for superior NMR performance and convenience of operation.
The determination of the in situ structure by nuclear spin contrast variation
Energy Technology Data Exchange (ETDEWEB)
Stuhrmann, H.B. [GKSS Forschungszentrum, Geesthacht (Germany); Nierhaus, K.H. [Max-Planch-Institut fuer Molekulare Genetik, Berlin (Germany)
1994-12-31
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.
Nuclear-Spin Gyroscope Based on an Atomic Co-Magnetometer
Romalis, Michael; Komack, Tom; Ghost, Rajat
2008-01-01
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.
Toward understanding of H3+ isotopic and nuclear spin fractionations in cold space
Hugo, E.; Asvany, O.; Harju, J.; Schlemmer, S.
2007-12-01
Two levels of statistical theories describing the H3+ plus H2 system and its isotopic variants at temperatures of astronomical interest (~ 10 K) are presented. The canonical approach accounting for the nuclear spins describes the system in a simple and convenient way. The microcanonical approach based on total energy, total angular momentum and total nuclear spin conservations yields state-to-state details. Non-thermal effects and astronomical implications are discussed.
Ding, Shangwu; McDowell, Charles A.; Ye, Chaohui; Zhan, Mingsheng; Zhu, Xiwen; Gao, Kelin; Sun, Xianping; Mao, Xi-An; Liu, Maili
2001-01-01
Magic-angle spinning (MAS) solid state nuclear magnetic resonance (NMR) spectroscopy is shown to be a promising technique for implementing quantum computing. The theory underlying the principles of quantum computing with nuclear spin systems undergoing MAS is formulated in the framework of formalized quantum Floquet theory. The procedures for realizing state labeling, state transformation and coherence selection in Floquet space are given. It suggests that by this method, the largest number o...
Nuclear structure effects in high-energy bremsstrahlung from spin-0 and spin-1/2 nuclei
Energy Technology Data Exchange (ETDEWEB)
Jakubassa-Amundsen, Doris [University of Munich (Germany)
2014-07-01
Bremsstrahlung from relativistic spin-polarized electrons colliding with inert nuclei is calculated by taking into account the nuclear form factors and the kinematical recoil. For the spin-1/2 nuclei additional contributions from the anomalous magnetic moment and the dynamical recoil are considered. Electron bremsstrahlung is described with the help of semirelativistic wavefunctions while nuclear bremsstrahlung, when present, is treated within the Born approximation. The triply differential bremsstrahlung cross section is integrated over the electron scattering angle to study the polarization correlations between the beam electron and the emitted photon. Results are shown for 20-120 MeV electrons colliding with protons, 19F, 64Zn and 89Y. It is also attempted to explain the background in electron spectra from nuclear excitation in terms of bremsstrahlung. As an example the 180 degree spectrum from exciting the giant M2 resonance in 90Zr by 42.7 MeV electrons is analyzed.
Luenser, Arne; Kussmann, Jörg; Ochsenfeld, Christian
2016-09-01
We present a (sub)linear-scaling algorithm to determine indirect nuclear spin-spin coupling constants at the Hartree-Fock and Kohn-Sham density functional levels of theory. Employing efficient integral algorithms and sparse algebra routines, an overall (sub)linear scaling behavior can be obtained for systems with a non-vanishing HOMO-LUMO gap. Calculations on systems with over 1000 atoms and 20 000 basis functions illustrate the performance and accuracy of our reference implementation. Specifically, we demonstrate that linear algebra dominates the runtime of conventional algorithms for 10 000 basis functions and above. Attainable speedups of our method exceed 6 × in total runtime and 10 × in the linear algebra steps for the tested systems. Furthermore, a convergence study of spin-spin couplings of an aminopyrazole peptide upon inclusion of the water environment is presented: using the new method it is shown that large solvent spheres are necessary to converge spin-spin coupling values.
Search for electric dipole moment in 129Xe atom using active nuclear spin maser
Ichikawa, Y.; Chikamori, M.; Ohtomo, Y.; Hikota, E.; Sakamoto, Y.; Suzuki, T.; Bidinosti, C. P.; Inoue, T.; Furukawa, T.; Yoshimi, A.; Suzuki, K.; Nanao, T.; Miyatake, H.; Tsuchiya, M.; Yoshida, N.; Shirai, H.; Ino, T.; Ueno, H.; Matsuo, Y.; Fukuyama, T.; Asahi, K.
2014-03-01
An experimental search for an electric dipole moment in the diamagnetic atom 129Xe is in progress through the precision measurement of spin precession frequency using an active nuclear spin maser. A 3He comagnetometer has been incorporated into the active spin maser system in order to cancel out the long-term drifts in the external magnetic field. Also, a double-cell geometry has been adopted in order to suppress the frequency shifts due to interaction with polarized Rb atoms. The first EDM measurement with the 129Xe active spin maser and the 3He comagnetometer has been conducted.
Search for electric dipole moment in 129Xe atom using active nuclear spin maser
Directory of Open Access Journals (Sweden)
Ichikawa Y.
2014-03-01
Full Text Available An experimental search for an electric dipole moment in the diamagnetic atom 129Xe is in progress through the precision measurement of spin precession frequency using an active nuclear spin maser. A 3He comagnetometer has been incorporated into the active spin maser system in order to cancel out the long-term drifts in the external magnetic field. Also, a double-cell geometry has been adopted in order to suppress the frequency shifts due to interaction with polarized Rb atoms. The first EDM measurement with the 129Xe active spin maser and the 3He comagnetometer has been conducted.
Energy Technology Data Exchange (ETDEWEB)
Adelnia, Fatemeh; Lascialfari, Alessandro [Dipartimento di Fisica, Università degli Studi di Milano and INSTM, Milano (Italy); Dipartimento di Fisica, Università degli Studi di Pavia and INSTM, Pavia (Italy); Mariani, Manuel [Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna (Italy); Ammannato, Luca; Caneschi, Andrea; Rovai, Donella [Dipartimento di Chimica, Università degli Studi di Firenze and INSTM, Firenze (Italy); Winpenny, Richard; Timco, Grigore [School of Chemistry, The University of Manchester, Manchester (United Kingdom); Corti, Maurizio, E-mail: maurizio.corti@unipv.it; Borsa, Ferdinando [Dipartimento di Fisica, Università degli Studi di Pavia and INSTM, Pavia (Italy)
2015-05-07
We present the room temperature proton nuclear magnetic resonance (NMR) nuclear spin-lattice relaxation rate (NSLR) results in two 1D spin chains: the Heisenberg antiferromagnetic (AFM) Eu(hfac){sub 3}NITEt and the magnetically frustrated Gd(hfac){sub 3}NITEt. The NSLR as a function of external magnetic field can be interpreted very well in terms of high temperature spin dynamics dominated by a long time persistence of the decay of the two-spin correlation function due to the conservation of the total spin value for isotropic Heisenberg chains. The high temperature spin dynamics are also investigated in Heisenberg AFM molecular rings. In both Cr{sub 8} closed ring and in Cr{sub 7}Cd and Cr{sub 8}Zn open rings, i.e., model systems for a finite spin segment, an enhancement of the low frequency spectral density is found consistent with spin diffusion but the high cut-off frequency due to intermolecular anisotropic interactions prevents a detailed analysis of the spin diffusion regime.
Noise-Resilient Quantum Computing with a Nitrogen-Vacancy Center and Nuclear Spins
Casanova, J.; Wang, Z.-Y.; Plenio, M. B.
2016-09-01
Selective control of qubits in a quantum register for the purposes of quantum information processing represents a critical challenge for dense spin ensembles in solid-state systems. Here we present a protocol that achieves a complete set of selective electron-nuclear gates and single nuclear rotations in such an ensemble in diamond facilitated by a nearby nitrogen-vacancy (NV) center. The protocol suppresses internuclear interactions as well as unwanted coupling between the NV center and other spins of the ensemble to achieve quantum gate fidelities well exceeding 99%. Notably, our method can be applied to weakly coupled, distant spins representing a scalable procedure that exploits the exceptional properties of nuclear spins in diamond as robust quantum memories.
Mitrikas, George; Papavassiliou, Georgios
2009-01-01
Since the idea of quantum information processing (QIP) fascinated the scientific community, electron and nuclear spins have been regarded as promising candidates for quantum bits (qubits). A fundamental challenge in the realization of a solid-state quantum computer is the construction of fast and reliable two-qubit quantum gates. Of particular interest in this direction are hybrid systems of electron and nuclear spins, where the two qubits are coupled through the hyperfine interaction. However, the significantly different gyromagnetic ratios of electron and nuclear spins do not allow for their coherent manipulation at the same time scale. Here 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 or -1/2), the nuclear spin can be locked in a desired state or oscillate between mI=+1/2 and mI=-1/2 on the na...
Multitudes of Stable States in a Periodically Driven Electron-Nuclear Spin System in a Quantum Dot
Korenev, V. L.
2010-01-01
The periodical modulation of circularly polarized light with a frequency close to the electron spin resonance frequency induces a sharp change of the single electron spin orientation. Hyperfine interaction provides a feedback, thus fixing the precession frequency of the electron spin in the external and the Overhauser field near the modulation frequency. The nuclear polarization is bidirectional and the electron-nuclear spin system (ENSS) possesses a few stable states. A similar frequency-loc...
Quadrupolar effects on nuclear spins of neutral arsenic donors in silicon
Franke, David P.; Pflüger, Moritz P. D.; Mortemousque, Pierre-André; Itoh, Kohei M.; Brandt, Martin S.
2016-04-01
We present electrically detected electron nuclear double resonance measurements of the nuclear spins of ionized and neutral arsenic donors in strained silicon. In addition to a reduction of the hyperfine coupling, we find significant quadrupole interactions of the nuclear spin of the neutral donors of the order of 10 kHz. By comparing these to the quadrupole shifts due to crystal fields measured for the ionized donors, we identify the effect of the additional electron on the electric field gradient at the nucleus. This extra component is expected to be caused by the coupling to electric field gradients created due to changes in the electron wave function under strain.
Nuclear and hadronic reaction mechanisms producing spin asymmetry
Indian Academy of Sciences (India)
Ken-Ichi Kubo
2001-08-01
We brieﬂy review concept of the quark recombination (QRC) model and a general success of the model. To solve the existing problem, so called anomalous spin observables, in the high energy hyperon spin phenomena, we propose a mechanism; the primarily produced quarks, which are predominantly and quarks, act as the leading partons to form the hyperons. Extension of the quark recombination concept with this mechanism is successful in providing a good account of the anomalous spin observables. Another kind of anomaly, the non-zero analysing power and spin depolarization in the hyperon productions, are also discussed and well understood by the presently proposed mechanism. Recently, a further difﬁculty was observed in an exclusive K+ production and we will indicate a possible diagram for resolving it.
Nuclear spin dynamics in solid 3He at ultralow temperatures
International Nuclear Information System (INIS)
In this thesis the experimental study of the spin dynamics of solid 3He is described. By means of magnetization measurements above 3 mK a Curie-Weiss behaviour was found with θW∼2.1 mK and by this an order parameter of J=θWkB/∼-0.5 KkB was observed, while in the range of 1 to 3 mK a pure Curie behaviour was found. By means of NMR measurements the values of τ1(6 mK)=240 ms±12 ms and τ1(1 mK)∼ 40 ms were determined, while spin-echo measurements yielded the spin-spin relaxation time τ2(6 mK)=4540 μs±140 μs. Furthermore neutron scattering studies were performed. (HSI)
Spin-orbit interaction in relativistic nuclear structure models
Ebran, J.-P.; Mutschler, A.; Khan, E.; Vretenar, D.
2016-08-01
Relativistic self-consistent mean-field (SCMF) models naturally account for the coupling of the nucleon spin to its orbital motion, whereas nonrelativistic SCMF methods necessitate a phenomenological ansatz for the effective spin-orbit potential. Recent experimental studies aim to explore the isospin properties of the effective spin-orbit interaction in nuclei. SCMF models are very useful in the interpretation of the corresponding data; however, standard relativistic mean-field and nonrelativistic Hartree-Fock models use effective spin-orbit potentials with different isovector properties, mainly because exchange contributions are not treated explicitly in the former. The impact of exchange terms on the effective spin-orbit potential in relativistic mean-field models is analyzed, and it is shown that it leads to an isovector structure similar to the one used in standard nonrelativistic Hartree-Fock models. Data on the isospin dependence of spin-orbit splittings in spherical nuclei could be used to constrain the isovector-scalar channel of relativistic mean-field models. The reproduction of the empirical kink in the isotope shifts of even Pb nuclei by relativistic effective interactions points to the occurrence of pseudospin symmetry in the single-neutron spectra in these nuclei.
Spin-orbit interaction in relativistic nuclear structure models
Ebran, J -P; Khan, E; Vretenar, D
2016-01-01
Relativistic self-consistent mean-field (SCMF) models naturally account for the coupling of the nucleon spin to its orbital motion, whereas non-relativistic SCMF methods necessitate a phenomenological ansatz for the effective spin-orbit potential. Recent experimental studies aim to explore the isospin properties of the effective spin-orbit interaction in nuclei. SCMF models are very useful in the interpretation of the corresponding data, however standard relativistic mean-field and non-relativistic Hartree-Fock models use effective spin-orbit potentials with different isovector properties, mainly because exchange contributions are not treated explicitly in the former. The impact of exchange terms on the effective spin-orbit potential in relativistic mean-field models is analysed, and it is shown that it leads to an isovector structure similar to the one used in standard non-relativistic Hartree-Fock. Data on the isospin dependence of spin-orbit splittings in spherical nuclei could be used to constrain the iso...
Dynamical nuclear spin polarization and the Zamboni effect in gated double quantum dots
Ramon, Guy; Hu, Xuedong
2006-01-01
A dynamical nuclear polarization scheme is studied in gated double dots. We demonstrate that a small polarization ($\\sim 0.5%$) is sufficient to enhance the singlet decay time by two orders of magnitude. This enhancement is attributed to an equilibration process between the nuclear reservoirs in the two dots accompanied by reduced fluctuations in the Overhauser fields, that are mediated by the electron-nuclear spin hyperfine interaction.
Coherent manipulation of an ensemble of nuclear spins in diamond for high precision rotation sensing
Jaskula, Jean-Christophe; Saha, Kasturi; Ajoy, Ashok; Cappellaro, Paola
2016-05-01
Gyroscopes find wide applications in everyday life from navigation and inertial sensing to rotation sensors in hand-held devices and automobiles. Current devices, based on either atomic or solid-state systems, impose a choice between long-time stability and high sensitivity in a miniaturized system. We are building a solid-state spin gyroscope associated with the Nitrogen-Vacancy (NV) centers in diamond take advantage of the efficient optical initialization and measurement offered by the NV electronic spin and the stability and long coherence time of the nuclear spin, which is preserved even at high defect density. In addition, we also investigate electro-magnetic noise monitoring and feedback schemes based on the coupling between the NV electronic and nuclear spin to achieve higher stability.
International Nuclear Information System (INIS)
We develop a theoretical description of Dynamic Nuclear Polarization (DNP) in solids under Magic Angle Spinning (MAS) to describe the magnetic field dependence of the DNP effect. The treatment is based on an efficient scheme for numerical solution of the Liouville-von Neumann equation, which explicitly takes into account the variation of magnetic interactions during the sample spinning. The dependence of the cross-effect MAS-DNP on various parameters, such as the hyperfine interaction, electron-electron dipolar interaction, microwave field strength, and electron spin relaxation rates, is analyzed. Electron spin relaxation rates are determined by electron paramagnetic resonance measurements, and calculations are compared to experimental data. Our results suggest that the observed nuclear magnetic resonance signal enhancements provided by MAS-DNP can be explained by discriminating between “bulk” and “core” nuclei and by taking into account the slow DNP build-up rate for the bulk nuclei
Probing the Nuclear Spin-Lattice Relaxation Time at the Nanoscale
Wagenaar, J. J. T.; Haan, A. M. J. den; Voogd, J.M.; Bossoni, L.; de Jong, T. A.; De Wit, M.; Bastiaans, K. M.; Thoen, D. J.; Endo, A; Klapwijk, T. M.; Zaanen, J.; Oosterkamp, T. H.
2016-01-01
Nuclear spin-lattice relaxation times are measured on copper using magnetic resonance force microscopy performed at temperatures down to 42 mK. The low temperature is verified by comparison with the Korringa relation. Measuring spin-lattice relaxation times locally at very low temperatures opens up the possibility to measure the magnetic properties of inhomogeneous electron systems realized in oxide interfaces, topological insulators and other strongly correlated electron systems such as high...
Probing the Nuclear Spin-Lattice Relaxation Time at the Nanoscale
Wagenaar, J. J. T.; den Haan, A. M. J.; de Voogd, J. M.; Bossoni, L.; de Jong, T. A.; de Wit, M.; Bastiaans, K. M.; Thoen, D. J.; Endo, A.; Klapwijk, T. M.; Zaanen, J.; Oosterkamp, T. H.
2016-07-01
Nuclear spin-lattice relaxation times are measured on copper using magnetic-resonance force microscopy performed at temperatures down to 42 mK. The low temperature is verified by comparison with the Korringa relation. Measuring spin-lattice relaxation times locally at very low temperatures opens up the possibility to measure the magnetic properties of inhomogeneous electron systems realized in oxide interfaces, topological insulators, and other strongly correlated electron systems such as high-Tc superconductors.
Studies on Entanglement in Nuclear and Electron Spin Systems for Quantum Computing
Rahimi, Robabeh
2006-01-01
In this work, we have been working on the concept of quantum entanglement. At first, we studied the theory of entanglement in its characterization and measurement, introducing a new scheme for detection of entanglement. The new approach links molecular-spin entities involving nuclear spins to quantum computing as more appropriate physical systems of interest. Then, we continued with the realization of entanglement in experiments. NMR has been the first choice due to its well approved advantag...
The MONSTER solves nuclear structure problems at low and high spins
International Nuclear Information System (INIS)
A microscopic, particle-number and spin conserving nuclear structure model is discussed. Within a unique theory the model can describe excitation energies, moments, transitions and spectroscopic factors at low and high spins of odd-mass and doubly-even nuclei in all mass regions. With a realistic two-body Hamiltonian extracted via a G-matric description from nucleon-nucleon scattering data. The model is here applied to nuclei in the A=130 region
Thurber, Kent R.; Tycko, Robert
2014-05-01
We report solid state 13C and 1H 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, 1H and cross-polarized 13C NMR signals from 15N,13C-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.
Energy Technology Data Exchange (ETDEWEB)
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)
2014-05-14
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.
International Nuclear Information System (INIS)
We report solid state 13C and 1H 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, 1H and cross-polarized 13C NMR signals from 15N,13C-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
Search for electric dipole moment in 129Xe atom using active nuclear spin maser
Ichikawa Y.; Chikamori M.; Ohtomo Y.; Hikota E.; Sakamoto Y.; Suzuki T; Bidinosti C.P.; Inoue T; Furukawa T; Yoshimi A.; Suzuki K.; Nanao T.; Miyatake H.; Tsuchiya M.; Yoshida N
2014-01-01
An experimental search for an electric dipole moment in the diamagnetic atom 129Xe is in progress through the precision measurement of spin precession frequency using an active nuclear spin maser. A 3He comagnetometer has been incorporated into the active spin maser system in order to cancel out the long-term drifts in the external magnetic field. Also, a double-cell geometry has been adopted in order to suppress the frequency shifts due to interaction with polarized Rb atoms. The first EDM m...
High-fidelity transfer and storage of photon states in a single nuclear spin
Yang, Sen; Wang, Ya; Rao, D. D. Bhaktavatsala; Hien Tran, Thai; Momenzadeh, Ali S.; Markham, M.; Twitchen, D. J.; Wang, Ping; Yang, Wen; Stöhr, Rainer; Neumann, Philipp; Kosaka, Hideo; Wrachtrup, Jörg
2016-08-01
Long-distance quantum communication requires photons and quantum nodes that comprise qubits for interaction with light and good memory capabilities, as well as processing qubits for the storage and manipulation of photons. Owing to the unavoidable photon losses, robust quantum communication over lossy transmission channels requires quantum repeater networks. A necessary and highly demanding prerequisite for these networks is the existence of quantum memories with long coherence times to reliably store the incident photon states. Here we demonstrate the high-fidelity (˜98%) coherent transfer of a photon polarization state to a single solid-state nuclear spin that has a coherence time of over 10 s. The storage process is achieved by coherently transferring the polarization state of a photon to an entangled electron-nuclear spin state of a nitrogen-vacancy centre in diamond. The nuclear spin-based optical quantum memory demonstrated here paves the way towards an absorption-based quantum repeater network.
High-fidelity transfer and storage of photon states in a single nuclear spin
Yang, Sen; Wang, Ya; Rao, D. D. Bhaktavatsala; Hien Tran, Thai; Momenzadeh, Ali S.; Markham, M.; Twitchen, D. J.; Wang, Ping; Yang, Wen; Stöhr, Rainer; Neumann, Philipp; Kosaka, Hideo; Wrachtrup, Jörg
2016-08-01
Long-distance quantum communication requires photons and quantum nodes that comprise qubits for interaction with light and good memory capabilities, as well as processing qubits for the storage and manipulation of photons. Owing to the unavoidable photon losses, robust quantum communication over lossy transmission channels requires quantum repeater networks. A necessary and highly demanding prerequisite for these networks is the existence of quantum memories with long coherence times to reliably store the incident photon states. Here we demonstrate the high-fidelity (∼98%) coherent transfer of a photon polarization state to a single solid-state nuclear spin that has a coherence time of over 10 s. The storage process is achieved by coherently transferring the polarization state of a photon to an entangled electron–nuclear spin state of a nitrogen–vacancy centre in diamond. The nuclear spin-based optical quantum memory demonstrated here paves the way towards an absorption-based quantum repeater network.
Probing the C₆₀ triplet state coupling to nuclear spins inside and out.
Filidou, Vasileia; Mamone, Salvatore; Simmons, Stephanie; Karlen, Steven D; Anderson, Harry L; Kay, Christopher W M; Bagno, Alessandro; Rastrelli, Federico; Murata, Yasujiro; Komatsu, Koichi; Lei, Xuegong; Li, Yongjun; Turro, Nicholas J; Levitt, Malcolm H; Morton, John J L
2013-09-13
The photoexcitation of functionalized fullerenes to their paramagnetic triplet electronic state can be studied by pulsed electron paramagnetic resonance (EPR) spectroscopy, whereas the interactions of this state with the surrounding nuclear spins can be observed by a related technique: electron nuclear double resonance (ENDOR). In this study, we present EPR and ENDOR studies on a functionalized exohedral fullerene system, dimethyl[9-hydro (C60-Ih)[5,6]fulleren-1(9H)-yl]phosphonate (DMHFP), where the triplet electron spin has been used to hyperpolarize, couple and measure two nuclear spins. We go on to discuss the extension of these methods to study a new class of endohedral fullerenes filled with small molecules, such as H₂@C₆₀, and we relate the results to density functional calculations. PMID:23918718
Thurber, Kent R.; Tycko, Robert
2012-08-01
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
2012-08-28
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 T(1e) 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
2012-01-01
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 rot...
Direct comparison of nuclear-spin-gyroscope schemes
Dong, Haifeng; Gao, Yang
2016-01-01
We demonstrate that NMR gyroscope and comagnetometer SERF gyroscope can be described with a common model, which explains the compensation and enhancement effects in the same way. The error models and the advantage/disadvantage of two kinds of atomic spin gyroscope are also discussed.
Hu, Huping; Wu, Maoxin
2004-01-01
A novel theory of consciousness is proposed in this paper. We postulate that consciousness is intrinsically connected to quantum spin since the latter is the origin of quantum effects in both Bohm and Hestenes quantum formulism and a fundamental quantum process associated with the structure of space-time. That is, spin is the “mind-pixel.” The unity of mind is achieved by entanglement of the mind-pixels. Applying these ideas to the particular structures and dynamics of the brain, we theorize ...
Effect of nuclear spin symmetry in cold and ultracold reactions: D + para/ortho-H$_2$
Simbotin, I.; Côté, R
2015-01-01
We report results for reaction and vibrational quenching of the collision D with para-H$_2$($v,j=0$) and ortho-H$_2$($v,j=1$) at cold and ultracold temperatures. We investigate the effect of nuclear spin symmetry for barrier dominated processes ($0\\le v\\le 4$) and for one barrierless case ($v=5$). We find resonant structures for energies in the range corresponding to 0.01--10 K, which depend on the nuclear spin of H$_2$, arising from contributions of specific partial waves. We discuss the imp...
Effect of nuclear spin symmetry in cold and ultracold reactions: D + para/ortho-H$_2$
Simbotin, I
2015-01-01
We report results for reaction and vibrational quenching of the collision D with para-H$_2$($v,j=0$) and ortho-H$_2$($v,j=1$) at cold and ultracold temperatures. We investigate the effect of nuclear spin symmetry for barrier dominated processes ($0\\le v\\le 4$) and for one barrierless case ($v=5$). We find resonant structures for energies in the range corresponding to 0.01--10 K, which depend on the nuclear spin of H$_2$, arising from contributions of specific partial waves. We discuss the implications on the results in this benchmark system for ultracold chemistry.
Clevenson, Hannah; Chen, Edward H.; Dolde, Florian; Teale, Carson; Englund, Dirk; Braje, Danielle
2016-08-01
We report on detailed studies of electronic and nuclear spin states in the diamond-nitrogen-vacancy (NV) center under weak transverse magnetic fields. We numerically predict and experimentally verify a previously unobserved NV hyperfine level anticrossing (LAC) occurring at bias fields of tens of gauss—two orders of magnitude lower than previously reported LACs at ˜500 and ˜1000 G axial magnetic fields. We then discuss how the NV ground-state Hamiltonian can be manipulated in this regime to tailor the NV's sensitivity to environmental factors and to map into the nuclear spin state.
DEFF Research Database (Denmark)
Enevoldsen, Thomas; Oddershede, Jens; Sauer, Stephan P. A.
1998-01-01
We present correlated calculations of the indirect nuclear spin-spin coupling constants of HD, HF, H2O, CH4, C2H2, BH, AlH, CO and N2 at the level of the second-order polarization propagator approximation (SOPPA) and the second-order polarization propagator approximation with coupled-cluster sing...
Canadian experience with spin-offs from nuclear technology
International Nuclear Information System (INIS)
The innovation process introduced into AECL's research laboratories is described, with its achievements in increased commercial and spin-off businesses. In particular, the role of the champion or entrepreneur is emphasized in the manner in which he/she interacts within a dedicated team to pursue each opportunity. Examples are provided of several commercial and business development opportunities resulting from the background research programs
Relativistic Force Field: Parametrization of (13)C-(1)H Nuclear Spin-Spin Coupling Constants.
Kutateladze, Andrei G; Mukhina, Olga A
2015-11-01
Previously, we reported a reliable DU8 method for natural bond orbital (NBO)-aided parametric scaling of Fermi contacts to achieve fast and accurate prediction of proton-proton spin-spin coupling constants (SSCC) in (1)H NMR. As sophisticated NMR experiments for precise measurements of carbon-proton SSCCs are becoming more user-friendly and broadly utilized by the organic chemistry community to guide and inform the process of structure determination of complex organic compounds, we have now developed a fast and accurate method for computing (13)C-(1)H SSCCs. Fermi contacts computed with the DU8 basis set are scaled using selected NBO parameters in conjunction with empirical scaling coefficients. The method is optimized for inexpensive B3LYP/6-31G(d) geometries. The parametric scaling is based on a carefully selected training set of 274 ((3)J), 193 ((2)J), and 143 ((1)J) experimental (13)C-(1)H spin-spin coupling constants reported in the literature. The DU8 basis set, optimized for computing Fermi contacts, which by design had evolved from optimization of a collection of inexpensive 3-21G*, 4-21G, and 6-31G(d) bases, offers very short computational (wall) times even for relatively large organic molecules containing 15-20 carbon atoms. The most informative SSCCs for structure determination, i.e., (3)J, were computed with an accuracy of 0.41 Hz (rmsd). The new unified approach for computing (1)H-(1)H and (13)C-(1)H SSCCs is termed "DU8c".
Relativistic Force Field: Parametrization of (13)C-(1)H Nuclear Spin-Spin Coupling Constants.
Kutateladze, Andrei G; Mukhina, Olga A
2015-11-01
Previously, we reported a reliable DU8 method for natural bond orbital (NBO)-aided parametric scaling of Fermi contacts to achieve fast and accurate prediction of proton-proton spin-spin coupling constants (SSCC) in (1)H NMR. As sophisticated NMR experiments for precise measurements of carbon-proton SSCCs are becoming more user-friendly and broadly utilized by the organic chemistry community to guide and inform the process of structure determination of complex organic compounds, we have now developed a fast and accurate method for computing (13)C-(1)H SSCCs. Fermi contacts computed with the DU8 basis set are scaled using selected NBO parameters in conjunction with empirical scaling coefficients. The method is optimized for inexpensive B3LYP/6-31G(d) geometries. The parametric scaling is based on a carefully selected training set of 274 ((3)J), 193 ((2)J), and 143 ((1)J) experimental (13)C-(1)H spin-spin coupling constants reported in the literature. The DU8 basis set, optimized for computing Fermi contacts, which by design had evolved from optimization of a collection of inexpensive 3-21G*, 4-21G, and 6-31G(d) bases, offers very short computational (wall) times even for relatively large organic molecules containing 15-20 carbon atoms. The most informative SSCCs for structure determination, i.e., (3)J, were computed with an accuracy of 0.41 Hz (rmsd). The new unified approach for computing (1)H-(1)H and (13)C-(1)H SSCCs is termed "DU8c". PMID:26414291
The improvement of spin-offs from national nuclear R and D activities in Korea
International Nuclear Information System (INIS)
The objectives of this study were to identify the influencing factors and suggest guidelines for improving the technological effectiveness of spin-offs concerning the national nuclear R and D programmes in Korea. In order to find the influencing factors on the technological effectiveness of the spin-off process, this study described the conceptual model which was composed of the technological effectiveness and three-group influencing factors such as donor, recipient and common factors. To validate the conceptual model, data were collected from twelve cases through in-depth interviews and well-prepared questionnaires, and the Spearman's correlation coefficient was employed. Finally, the influencing factors at each stage of the spin-off process were integrated to draw up a schematic framework and evaluate the implications for the improvement of technological effectiveness of spin-offs. (author)
Thermal mixing in multiple-pulse nuclear quadrupole resonance spin-locking
International Nuclear Information System (INIS)
We report on an experimental and theoretical nuclear quadrupole resonance (NQR) multiple-pulse spin-locking study of the thermal mixing process in solids containing nuclei of two different sorts, I>1/2 and S = 1/2, coupled by dipole-dipole interactions and influenced by an external magnetic field. Two coupled equations for the inverse spin temperatures of both the spin systems describing the mutual spin-lattice relaxation and the thermal mixing were obtained using the method of the nonequilibrium state operator. It is shown that the relaxation process is realized with non-exponential time dependence described by a sum of two exponents. The calculated relaxation time versus the multiple-pulse field parameters agrees well with the obtained experimental data in 1,4-dichloro-2-nitrobenzene. The calculated magnetization relaxation time versus the strength of the applied magnetic field agrees well with the obtained experimental data
DEFF Research Database (Denmark)
Jacobsen, H.J.; Skibsted, J.; Kristensen, Martin;
2001-01-01
Magic-angle spinning nuclear magnetic resonance spectra of 31P and 29Si have been achieved for a thin silica film doped with only 1.8% 31P and deposited by plasma enhanced chemical vapor deposition on a pure silicon wafer. The observation of a symmetric 31P chemical shift tensor is consistent...
Extended s± scenario for the nuclear spin-lattice relaxation rate in superconducting pnictides
Parker, D.; Dolgov, O.V.; Korshunov, M.M.; Golubov, A.A.; Mazin, I.I.
2008-01-01
Recently, several measurements of the nuclear spin-lattice relaxation rate T_{1}^{-1} in the superconducting Fe pnictides have been reported. These measurements generally show no coherence peak below Tc and indicate a low-temperature power-law behavior, the characteristics commonly t
The role of level anti-crossings in nuclear spin hyperpolarization
Ivanov, Konstantin L.; Pravdivtsev, Andrey N.; Yurkovskaya, Alexandra V.; Vieth, Hans Martin; Kaptein, R
2014-01-01
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,
Coherent transfer of nuclear spin polarization in field-cycling NMR experiments.
Pravdivtsev, Andrey N; Yurkovskaya, Alexandra V; Vieth, Hans-Martin; Ivanov, Konstantin L
2013-12-28
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. PMID:24387362
Coherent transfer of nuclear spin polarization in field-cycling NMR experiments
Energy Technology Data Exchange (ETDEWEB)
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)
2013-12-28
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.
Reanalysis of nuclear spin matrix elements for dark matter spin-dependent scattering
Cannoni, M.
2013-04-01
We show how to include in the existing calculations for nuclei other than Xe129 and Xe131 the corrections to the isovector coupling arising in chiral effective field theory recently found in Menendez et al. [Phys. Rev. D 86, 103511 (2012)PRVDAQ1550-7998]. The dominant, momentum-independent, two-body current effect can be taken into account by formally redefining the static spin matrix elements ⟨Sp,n⟩. By further using the normalized form factor at q≠0 built with the one-body level structure functions, we show that the weakly interacting massive particles (WIMP)-nucleus cross section and the upper limits on the WIMP-nucleon cross sections coincide with the ones derived by using the exact functions at the two-body level. We explicitly show it in the case of XENON100 limits on the WIMP-neutron cross section, and we recalculate the limits on the WIMP-proton spin-dependent cross section set by COUPP. We also give practical formulas to obtain ⟨Sp,n⟩ given the structure functions in the various formalisms and notations existing in the literature. We argue that the standard treatment of the spin-dependent cross section in terms of three independent isospin functions, S00(q), S11(q), and S01(q), is redundant in the sense that the interference function S01(q) is the double product |S01(q)|=2S00(q)S11(q) even when including the new effective field theory corrections.
Spatial gradient of dynamic nuclear spin polarization induced by breakdown of quantum Hall effect
Kawamura, Minoru; Kono, Kimitoshi; Hashimoto, Yoshiaki; Katsumoto, Shingo; Machida, Tomoki
2010-01-01
We studied spatial distribution of dynamic nuclear polarization (DNP) in a Hall-bar device in a breakdown regime of the quantum Hall effect (QHE). We detected nuclear magnetic resonance (NMR) signals from the polarized nuclear spins by measuring the Hall voltage $V_{xy}$ using three pairs of voltage probes attached to the conducting channel of the Hall bar. We find that the amplitude of the NMR signal depends on the position of the Hall voltage probes and that the largest NMR signal is obtain...
Energy Technology Data Exchange (ETDEWEB)
Schmid, K.W.; Gruemmer, F.; Faessler, A.
1984-01-01
In the first part of the present series of two papers we discussed several nuclear structure models all working in configuration spaces consisting of spin- and number-projected quasiparticle determinants. In the present paper a particular version of the numerically simplest of these models is presented. This model approximates the nuclear wave functions by linear combinations of the angular momentum- and particle number-projected Hartree-Fock-Bogoliubov vacuum and the equally spin- and number-projected two quasiparticle excitations with respect to it. The model allows the use of realistic two body interactions and rather large model spaces. It can hence be applied to a large number of nuclear structure problems in various mass regions. First applications have been performed for the nuclei /sup 20/Ne, /sup 22/Ne, /sup 46/Ti, and /sup 164/Er. In all these cases the results are very encouraging.
Resonance-inclined optical nuclear spin polarization of liquids in diamond structures
Chen, Qiong; Jelezko, Fedor; Retzker, Alex; Plenio, Martin B
2015-01-01
Dynamic nuclear polarization (DNP) of molecules in a solution at room temperature has potential to revolutionize nuclear magnetic resonance spectroscopy and imaging. The prevalent methods for achieving DNP in solutions are typically most effective in the regime of small interaction correlation times between the electron and nuclear spins, limiting the size of accessible molecules. To solve this limitation, we design a mechanism for DNP in the liquid phase that is applicable for large interaction correlation times. Importantly, while this mechanism makes use of a resonance condition similar to solid-state DNP, the polarization transfer is robust to a relatively large detuning from the resonance due to molecular motion. We combine this scheme with optically polarized nitrogen vacancy (NV) center spins in nanodiamonds to design a setup that employs optical pumping and is therefore not limited by room temperature electron thermal polarisation. We illustrate numerically the effectiveness of the model in a flow cel...
Advances and applications of dynamic-angle spinning nuclear magnetic resonance
International Nuclear Information System (INIS)
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 87Rb and 85Rb 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
Advances and applications of dynamic-angle spinning nuclear magnetic resonance
Energy Technology Data Exchange (ETDEWEB)
Baltisberger, J.H.
1993-06-01
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.
Energy Technology Data Exchange (ETDEWEB)
Jonischkeit, T.
2004-07-01
Hydrogenation reactions conducted with molecular hydrogen enriched in its nuclear singlet state (i.e., enriched in parahydrogen) can lead to strongly enhanced absorption and emission signals in the NMR (nuclear magnetic resonance) spectra of reaction intermediates or products if they are recorded during or shortly after the reaction. This hyperpolarization phenomenon has been termed PHIP (parahydrogen induced polarization) and is recurrently used to study reaction mechanisms and kinetics of catalytic hydrogenations. A similar effect has been observed with hydrogen enriched in its nuclear triplet state (enriched in orthohydrogen). In this thesis, it is shown both theoretically and experimentally that not only enriched hydrogen samples (ortho- or parahydrogen) but also hydrogen without isomer enrichment (thermal hydrogen) is able to induce NMR hyperpolarization. This new twist to the PHIP phenomenon is utilized for of a sensitive method to measure spin-isomer ratios in hydrogen gas samples. Both line shape of PHIP signals and relaxation of hyperpolarized spin systems depend on the external magnetic field. Because some of the recent PHIP research is aimed at contrast enhancement in MRI (magnetic resonance imaging), line shape and relaxation studies were conducted, which are particularly useful for the advancement of MRI diagnostics. Like hydrogen, other molecules with C2 symmetry are also composed of ortho- and para-isomers. Consequently, the concept of nuclear-spin hyperpolarization was extended to reactions with {sup 2}H{sub 2} molecules (i.e., deuterations) and {sup 17}O{sub 2} molecules (peroxidations). Experimental studies conducted with samples enriched in orthodeuterium show signal patterns similar to PHIP. These patterns and their signal enhancements were investigated depending on particular experimental conditions such as conducting the reaction in a high magnetic field (PASADENA) or in a low magnetic field (ALTADENA) before recording the NMR spectrum. The
Nuclear Spin Relaxation and Molecular Interactions of a Novel Triazolium-Based Ionic Liquid
Energy Technology Data Exchange (ETDEWEB)
Allen, Jesse J; Schneider, Yanika; Kail, Brian W; Luebke, David R; Nulwala, Hunaid; Damodaran, Krishnan
2013-04-11
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.
Ma, Wen-Long; Liu, Ren-Bao
2016-08-01
Single-molecule sensitivity of nuclear magnetic resonance (NMR) and angstrom resolution of magnetic resonance imaging (MRI) are the highest challenges in magnetic microscopy. Recent development in dynamical-decoupling- (DD) enhanced diamond quantum sensing has enabled single-nucleus NMR and nanoscale NMR. Similar to conventional NMR and MRI, current DD-based quantum sensing utilizes the "frequency fingerprints" of target nuclear spins. The frequency fingerprints by their nature cannot resolve different nuclear spins that have the same noise frequency or differentiate different types of correlations in nuclear-spin clusters, which limit the resolution of single-molecule MRI. Here we show that this limitation can be overcome by using "wave-function fingerprints" of target nuclear spins, which is much more sensitive than the frequency fingerprints to the weak hyperfine interaction between the targets and a sensor under resonant DD control. We demonstrate a scheme of angstrom-resolution MRI that is capable of counting and individually localizing single nuclear spins of the same frequency and characterizing the correlations in nuclear-spin clusters. A nitrogen-vacancy-center spin sensor near a diamond surface, provided that the coherence time is improved by surface engineering in the near future, may be employed to determine with angstrom resolution the positions and conformation of single molecules that are isotope labeled. The scheme in this work offers an approach to breaking the resolution limit set by the "frequency gradients" in conventional MRI and to reaching the angstrom-scale resolution.
Employing Forbidden Transitions as Qubits in a Nuclear Spin-Free Chromium Complex.
Fataftah, Majed S; Zadrozny, Joseph M; Coste, Scott C; Graham, Michael J; Rogers, Dylan M; Freedman, Danna E
2016-02-01
The implementation of quantum computation (QC) would revolutionize scientific fields ranging from encryption to quantum simulation. One intuitive candidate for the smallest unit of a quantum computer, a qubit, is electronic spin. A prominent proposal for QC relies on high-spin magnetic molecules, where multiple transitions between the many MS levels are employed as qubits. Yet, over a decade after the original notion, the exploitation of multiple transitions within a single manifold for QC remains unrealized in these high-spin species due to the challenge of accessing forbidden transitions. To create a proof-of-concept system, we synthesized the novel nuclear spin-free complex [Cr(C3S5)3](3-) with precisely tuned zero-field splitting parameters that create two spectroscopically addressable transitions, with one being a forbidden transition. Pulsed electron paramagnetic resonance (EPR) measurements enabled the investigation of the coherent lifetimes (T2) and quantum control (Rabi oscillations) for two transitions, one allowed and one forbidden, within the S = (3)/2 spin manifold. This investigation represents a step forward in the development of high-spin species as a pathway to scalable QC systems within magnetic molecules.
Microscopic control of $^{29}$Si nuclear spins near phosphorus donors in silicon
Järvinen, J; Ahokas, J; Sheludyakov, S; Vainio, O; Lehtonen, L; Vasiliev, S; Fujii, Y; Mitsudo, S; Mizusaki, T; Gwak, M; Lee, SangGap; Lee, Soonchil; Vlasenko, L
2014-01-01
Dynamic nuclear polarization of $^{29}$Si nuclei in resolved lattice sites near the phosphorus donors in natural silicon of has been created using the Overhauser and solid effects. Polarization has been observed as a pattern of well separated holes and peaks in the electron spin resonance line of the donor. The Overhauser effect in ESR hole burning experiments was used to manipulate the polarization of $^{29}$Si spins at ultra low (100-500 mK) temperatures and in high magnetic field of 4.6 T. Extremely narrow holes of 15 mG width were created after several seconds of pumping.
International Nuclear Information System (INIS)
Interaction of incident nuclear particle beam with J = 1/2 (neutrons) spin and (J = 1/2) protons with the target substance is considered. It is shown that neutron polarization at the target exit and neutron transparency (G) of the target depend significantly on incident wave amplitude level and physical parameter values which characterize the target, such as target temperature, resonator mirror reflection factor, number of spins interacting with the field, etc. Under interaction of neutrons with a target resonator which features a high mirror reflection factor and low losses for absorption which is not related to magnetic dipole absorption, a bistable response of neutron polarization and G manifests itself. 1 ref
Energy Technology Data Exchange (ETDEWEB)
Wylie, Benjamin J. [Columbia University, Department of Chemistry (United States); Dzikovski, Boris G. [Cornell University, National Biomedical Center for Advanced ESR Technology, Department of Chemistry and Chemical Biology (United States); Pawsey, Shane; Caporini, Marc; Rosay, Melanie [Bruker BioSpin Corporation (United States); Freed, Jack H. [Cornell University, National Biomedical Center for Advanced ESR Technology, Department of Chemistry and Chemical Biology (United States); McDermott, Ann E., E-mail: aem5@columbia.edu [Columbia University, Department of Chemistry (United States)
2015-04-15
We demonstrate that dynamic nuclear polarization of membrane proteins in lipid bilayers may be achieved using a novel polarizing agent: pairs of spin labels covalently bound to a protein of interest interacting at an intermolecular interaction surface. For gramicidin A, nitroxide tags attached to the N-terminal intermolecular interface region become proximal only when bimolecular channels forms in the membrane. We obtained signal enhancements of sixfold for the dimeric protein. The enhancement effect was comparable to that of a doubly tagged sample of gramicidin C, with intramolecular spin pairs. This approach could be a powerful and selective means for signal enhancement in membrane proteins, and for recognizing intermolecular interfaces.
Isovector spin observables in nuclear charge reactions at LAMPF
International Nuclear Information System (INIS)
LAMPF has undertaken a major development program to upgrade facilities for nuclear charge-exchange studies at intermediate energies. The major components of this upgrade are a medium-resolution spectrometer and neutron time-of-flight system for good resolution (δ E < 1 MeV) charge-exchange perograms in (n,p) and (p,n) respectively. Major emphasis is placed on polarization phenomena using polarized beams and analyzing the polarization of the outgoing particle
Waeber, A. M.; Hopkinson, M.; Farrer, I.; Ritchie, D. A.; Nilsson, J.; Stevenson, R. M.; Bennett, A. J.; Shields, A. J.; Burkard, G.; Tartakovskii, A. I.; Skolnick, M. S.; Chekhovich, E. A.
2016-07-01
One of the key challenges in spectroscopy is the inhomogeneous broadening that masks the homogeneous spectral lineshape and the underlying coherent dynamics. Techniques such as four-wave mixing and spectral hole-burning are used in optical spectroscopy, and spin-echo in nuclear magnetic resonance (NMR). However, the high-power pulses used in spin-echo and other sequences often create spurious dynamics obscuring the subtle spin correlations important for quantum technologies. Here we develop NMR techniques to probe the correlation times of the fluctuations in a nuclear spin bath of individual quantum dots, using frequency-comb excitation, allowing for the homogeneous NMR lineshapes to be measured without high-power pulses. We find nuclear spin correlation times exceeding one second in self-assembled InGaAs quantum dots--four orders of magnitude longer than in strain-free III-V semiconductors. This observed freezing of the nuclear spin fluctuations suggests ways of designing quantum dot spin qubits with a well-understood, highly stable nuclear spin bath.
Spin-dipole strength functions of $^4$He with realistic nuclear forces
Horiuchi, W
2013-01-01
Both isoscalar and isovector spin-dipole excitations of $^4$He are studied using realistic nuclear forces in the complex scaling method. The ground state of $^4$He and discretized continuum states with $J^{\\pi}=0^-, 1^-, 2^-$ 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 $^4$He.
Spin assignments of nuclear levels above the neutron binding energy in $^{88}$Sr
Neutron resonances reveal nuclear levels in the highly excited region of the nucleus around the neutron binding energy. Nuclear level density models are therefore usually calibrated to the number of observed levels in neutron-induced reactions. The gamma-ray cascade from the decay of the highly excited compound nucleus state to the ground state show dierences dependent on the initial spin. This results in a dierence in the multiplicity distribution which can be exploited. We propose to use the 4${\\pi}$ total absorption calorimeter (TAC) at the n TOF facility to determine the spins of resonances formed by neutrons incident on a metallic $^{87}$Sr sample by measuring the gamma multiplicity distributions for the resolved resonances. In addition we would like to use the available enriched $^{87}$Sr target for cross section measurements with the C$\\scriptscriptstyle{6}$D$\\scriptscriptstyle{6}$ detector setup.
Ding, S; Ye, C; Zhan, M S; Zhu, X; Gao, K; Sun, X; Mao, X A; Liu, M; Ding, Shangwu; Dowell, Charles A. Mc; Ye, Chaohui; Zhan, Mingsheng; Zhu, Xiwen; Gao, Kelin; Sun, Xianping; Mao, Xi-An; Liu, Maili
2001-01-01
Magic-angle spinning (MAS) solid state nuclear magnetic resonance (NMR) spectroscopy is shown to be a promising technique for implementing quantum computing. The theory underlying the principles of quantum computing with nuclear spin systems undergoing MAS is formulated in the framework of formalized quantum Floquet theory. The procedures for realizing state labeling, state transformation and coherence selection in Floquet space are given. It suggests that by this method, the largest number of qubits can easily surpass that achievable with other techniques. Unlike other modalities proposed for quantum computing, this method enables one to adjust the dimension of the working state space, meaning the number of qubits can be readily varied. The universality of quantum computing in Floquet space with solid state NMR is discussed and a demonstrative experimental implementation of Grover's search is given.
Research on high spin structures of N=79 isotones in A=135 nuclear region
International Nuclear Information System (INIS)
The progress of research on the high spin states at N=79 isotopes 135Ba, 137Ce and 139Nd in A=135 neutron-deficient region by the research group of Tsinghua University has been reviewed. The experiments were carried out by using in-beam γ-ray spectroscopy technology and heavy ion nuclear reactions 130Te(9Be, 4n), 124Sn(18O, 5n) and 128Te(16O, 5n) at China Institute of Atomic Energy (CIAE). The high spin level schemes of these nuclei have been expanded. The results indicate that the lower spin states of these nuclei originated from νh11/2-1 hole state coupling with the neighboring even-even nucleus cores. All the deformation parameters γ values of these three isotones are larger than 30 degree, which indicates that they have triaxial deformation with oblate side. The prolate-oblate transition in Ba, Ce and Nd isotopic chains indeed happens between N=77 and N=79. Through systematical comparison with the neighboring isotones, the configurations for some middle spin state levels have been assigned. At the high spin states, one oblate band in 137Ce and three ones in 139Nd with γ≅-60 degree were discovered. The origination and structural character of these oblate bands have been discussed. (authors)
Nuclear structure aspects of spin-independent WIMP scattering off xenon
Vietze, L; Menéndez, J; Haxton, W C; Schwenk, A
2014-01-01
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...
High fidelity transfer and storage of photon states in a single nuclear spin
Yang, Sen; Wang, Ya; Rao, D. D. Bhaktavatsala; Tran, Thai Hien; Momenzadeh, S. Ali; Nagy, Roland; Markham, M.; Twitchen, D. J.; Ping WANG; Yang, Wen; Stoehr, Rainer; Neumann, Philipp; Kosaka, Hideo; Wrachtrup, Joerg
2015-01-01
Building a quantum repeater network for long distance quantum communication requires photons and quantum registers that comprise qubits for interaction with light, good memory capabilities and processing qubits for storage and manipulation of photons. Here we demonstrate a key step, the coherent transfer of a photon in a single solid-state nuclear spin qubit with an average fidelity of 98% and storage over 10 seconds. The storage process is achieved by coherently transferring a photon to an e...
Sensing and atomic-scale structure analysis of single nuclear spin clusters in diamond
Shi, Fazhan; Kong, Xi; Wang, Pengfei; Kong, Fei; Zhao, Nan; Liu, Ren-Bao; Du, Jiangfeng
2013-01-01
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 dec...
Contrast generation in the nuclear-spin tomography by pulsed ultrasound
International Nuclear Information System (INIS)
In the framework of this thesis a combined method of ultrasound and nuclear-spin tomography is presented. Via ultrasound pulses by the sound-radiation force in liquids and tissue phantoms motions are generated, which depend on ther viscoelastic properties. This motions are made visible by a motion-sensitive tomograph sequence in the phase image of the tomograph in form of a phase change. The first measurements on simple phantoms and liquids are presented.
Controlling nuclear spin exchange via optical Feshbach resonances in ${}^{171}$Yb
Reichenbach, Iris; Julienne, Paul S.; Deutsch, Ivan H.
2009-01-01
Nuclear spin exchange occurs in ultracold collisions of fermionic alkaline-earth-like atoms due to a difference between s- and p-wave phase shifts. We study the use of an optical Feshbach resonance, excited on the ${}^1S_0 \\to {}^3P_1$ intercombination line of ${}^{171}$Yb, to affect a large modification of the s-wave scattering phase shift, and thereby optically mediate nuclear exchange forces. We perform a full multichannel calculation of the photoassociation resonances and wave functions a...
Hoffman, Brian M.
2003-01-01
This perspective discusses the ways that advanced paramagnetic resonance techniques, namely electron-nuclear double resonance (ENDOR) and electron spin-echo envelope modulation (ESEEM) spectroscopies, can help us understand how metal ions function in biological systems.
Pion-nucleus inelastic scattering: Reaction contributions and nuclear spin determinations
International Nuclear Information System (INIS)
Formulas for pion-nucleus inelastic scattering are presented in a form that may suggest experiments to isolate various contributions to the reaction, including S-wave, P-wave spin and nonspin flip, and effects of nucleon Fermi motion. Adopting a form of the distorted wave impulse appoximation, we obtain an expression for inelastic cross sections that clearly separate the pion laboratory energy (E), three-momentum transfer (q), and scattering angle (theta) dependences. The result is similar to the separation of longitudinal and transverse form factors in inelastic electron scattering. By varying the energy of the incident pion, but working at fixed q, one can determine whether a given nuclear excitation has natural or unnatural parity. By working at fixed theta, and varying E and thus q, one can isolate different reaction contributions: spin, scalar, and ''convection current.'' We also discuss the potential usefulness of studying the energy dependence of angle-integrated differential cross sections at fixed energy loss. The predictions of our formulas are in good agreement with recent data on natural and unnatural parity excitations in 12C(π,π')12C*. Thus, this approach may be useful in analyzing future data in which the final nuclear spin is uncertain. Future experiments with selective q, E, and theta variations to separate nuclear structure from reaction-mechanism uncertainties are suggested
Quantum cognition: The possibility of processing with nuclear spins in the brain
Fisher, Matthew P. A.
2015-11-01
The possibility that quantum processing with nuclear spins might be operative in the brain is explored. Phosphorus is identified as the unique biological element with a nuclear spin that can serve as a qubit for such putative quantum processing-a neural qubit-while the phosphate ion is the only possible qubit-transporter. We identify the "Posner molecule", Ca9(PO4)6, as the unique molecule that can protect the neural qubits on very long times and thereby serve as a (working) quantum-memory. A central requirement for quantum-processing is quantum entanglement. It is argued that the enzyme catalyzed chemical reaction which breaks a pyrophosphate ion into two phosphate ions can quantum entangle pairs of qubits. Posner molecules, formed by binding such phosphate pairs with extracellular calcium ions, will inherit the nuclear spin entanglement. A mechanism for transporting Posner molecules into presynaptic neurons during vesicle endocytosis is proposed. Quantum measurements can occur when a pair of Posner molecules chemically bind and subsequently melt, releasing a shower of intra-cellular calcium ions that can trigger further neurotransmitter release and enhance the probability of post-synaptic neuron firing. Multiple entangled Posner molecules, triggering non-local quantum correlations of neuron firing rates, would provide the key mechanism for neural quantum processing. Implications, both in vitro and in vivo, are briefly mentioned.
Diffusion-mediated nuclear spin phase decoherence in cylindrically porous materials
Knight, Michael J.; Kauppinen, Risto A.
2016-08-01
In NMR or MRI of complex materials, including biological tissues and porous materials, magnetic susceptibility differences within the material result in local magnetic field inhomogeneities, even if the applied magnetic field is homogeneous. Mobile nuclear spins move though the inhomogeneous field, by translational diffusion and other mechanisms, resulting in decoherence of nuclear spin phase more rapidly than transverse relaxation alone. The objective of this paper is to simulate this diffusion-mediated decoherence and demonstrate that it may substantially reduce coherence lifetimes of nuclear spin phase, in an anisotropic fashion. We do so using a model of cylindrical pores within an otherwise homogeneous material, and calculate the resulting magnetic field inhomogeneities. Our simulations show that diffusion-mediated decoherence in a system of parallel cylindrical pores is anisotropic, with coherence lifetime minimised when the array of cylindrical pores is perpendicular to B0. We also show that this anisotropy of coherence lifetime is reduced if the orientations of cylindrical pores are disordered within the system. In addition we characterise the dependence on B0, the magnetic susceptibility of the cylindrical pores relative to the surroundings, the diffusion coefficient and cylinder wall thickness. Our findings may aid in the interpretation of NMR and MRI relaxation data.
Institute of Scientific and Technical Information of China (English)
Luo Jun; Sun Xian-Ping; Zeng Xi-Zhi; Zhan Ming-Sheng
2007-01-01
Nuclear-spin states of gaseous-state Cs atoms in the ground state are optically manipulated using a Ti:sapphire laser in a magnetic field of 1.516 T, in which optical coupling of the nuclear-spin states is achieved through hyperfine interactions between electrons and nuclei. The steady-state population distribution in the hyperfine Zeeman sublevels of the ground state is detected by using a tunable diode laser. Furthermore, the state population transfer among the of Cs in the ground state due to stochastic collisions between Cs atoms and buffer-gas molecules, is studied at different of the hyperfine interaction can strongly cause the state population transfer and spin-state interchange among the hyperfine Zeeman sublevels. The calculated results maybe explain the steady-state population in hyperfine Zeeman sublevels in terms of rates of optical-pumping, electron-spin flip, nuclear spin flip, and electron-nuclear spin flip-flop transitions among the hyperfine Zeeman sublevels of the ground state of Cs atoms. This method may be applied to the nuclear-spin-based solid-state quantum computation.
Thurber, Kent R.; Tycko, Robert
2014-01-01
We report solid state 13C and 1H 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, 1H and cross-polarized 13C NMR signals from 15N,13C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitr...
A NEW METHOD FOR EXTRACTING SPIN-DEPENDENT NEUTRON STRUCTURE FUNCTIONS FROM NUCLEAR DATA
Energy Technology Data Exchange (ETDEWEB)
Kahn, Y.F.; Melnitchouk, W.
2009-01-01
High-energy electrons are currently the best probes of the internal structure of nucleons (protons and neutrons). By collecting data on electrons scattering off light nuclei, such as deuterium and helium, one can extract structure functions (SFs), which encode information about the quarks that make up the nucleon. Spin-dependent SFs, which depend on the relative polarization of the electron beam and the target nucleus, encode quark spins. Proton SFs can be measured directly from electron-proton scattering, but those of the neutron must be extracted from proton data and deuterium or helium-3 data because free neutron targets do not exist. At present, there is no reliable method for accurately determining spin-dependent neutron SFs in the low-momentum-transfer regime, where nucleon resonances are prominent and the functions are not smooth. The focus of this study was to develop a new method for extracting spin-dependent neutron SFs from nuclear data. An approximate convolution formula for nuclear SFs reduces the problem to an integral equation, for which a recursive solution method was designed. The method was then applied to recent data from proton and deuterium scattering experiments to perform a preliminary extraction of spin-dependent neutron SFs in the resonance region. The extraction method was found to reliably converge for arbitrary test functions, and the validity of the extraction from data was verifi ed using a Bjorken integral, which relates integrals of SFs to a known quantity. This new information on neutron structure could be used to assess quark-hadron duality for the neutron, which requires detailed knowledge of SFs in all kinematic regimes.
Rotor Design for High Pressure Magic Angle Spinning Nuclear Magnetic Resonance
International Nuclear Information System (INIS)
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 deg 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.
Single particle potentials of asymmetric nuclear matter in different spin-isospin channels
Institute of Scientific and Technical Information of China (English)
ZUO Wei; GAN Sheng-Xin; U.Lombardo
2012-01-01
We investigate the neutron and proton single particle (s.p.) potentials of asymmetric nuclear matter and their isospin dependence in various spin-isospin ST channels within the framework of the BruecknerHartree-Fock approach.It is shown that in symmetric nuclear matter,the s.p.potentials in both the isospinsinglet T =0 channel and isospin-triplet T =1 channel are essentially attractive,and the magnitudes in the two different channels are roughly the same.In neutron-rich nuclear matter,the isospin-splitting of the proton and neutron s.p.potentials turns out to be mainly determined by the isospin-singlet T =0 channel contribution which becomes more attractive for the proton and more repulsive for the neutron at higher asymmetries.
Nuclear spin--lattice relaxation measurements in small superconducting aluminum partilces
Energy Technology Data Exchange (ETDEWEB)
Tse, P.K.; MacLaughlin, D.E.
1980-05-01
The /sup 27/Al nuclear spin-lattice relaxation times T/sub 1/ have been measured in the normal and superconducting states of small aluminum particles with average particle diameters ranging from 170 to 750 A. Experiments were performed in magnetic fields between 0 and 1200 Oe and at temperatures between 0.5 and 4.2 K. The nuclear spin-lattice relaxation rate 1/T/sub 1/ at zero and low magnetic fields is characterized by a sum of a Korringa rate (due to conduction-electron spin-flip scattering) and an additonal rate, which is attributed to a crossfield (1200 Oe), where the Zeeman energy either dominates in larger particles or play an important role in smaller particles, measured rates for all three samples are in good agrreement with the microscopic theory of Sone. At low fields (H< or =150 Oe) our T/sub 1/ results, which show a strong field dependence and less effect of superconducting fluctuations near T/sub c/, are in disagreement with Sone. We suggest that the theory has overestimated the effects of fluctuations on quasiparticle excitations at these low fields.
Spin and temperature dependence of nuclear deformation using alpha-gamma angular correlations
International Nuclear Information System (INIS)
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 γ-ray angular distributions, for each event, using the spin spectrometer. α-particle anisotropies have been extracted for the compound nuclear systems: 110Sn*(94 MeV), 114Sn*(80 MeV), 138Nd*(82 MeV), 164Yb*(67 MeV) and 170Yb*(135 MeV) as a function of the α-particle energy and γ-ray multiplicity. The results are compared with statistical model calculations using transmission coefficients from a spherically symmetric optical model potential. The trend of the anisotropy coefficients below the evaporation Coulomb barrier is consistent with spherical emitting shapes in the case of the Sn* isotopes. Small deformation effects are suggested by the 138Nd* and 164Yb* data. The 170Yb* data indicate a large deformation which increases considerably with increasing spin. These results are in agreement with findings for similar systems in which the decay of the giant resonances built on excited states have been studied. 16 refs., 5 figs
Progress of the 129Xe EDM search using active feedback nuclear spin maser
Sato, Tomoya; Ichikawa, Yuichi; Ohtomo, Yuichi; Sakamoto, Yu; Kojima, Shuichiro; Funayama, Chikako; Suzuki, Takahiro; Chikamori, Masatoshi; Hikota, Eri; Tsuchiya, Masato; Furukawa, Takeshi; Yoshimi, Akihiro; Bidinosti, Christopher; Ino, Takashi; Ueno, Hideki; Matsuo, Yukari; Fukuyama, Takeshi; Asahi, Koichiro
2014-09-01
A permanent electric dipole moment (EDM) of a particle is an extremely sensitive probe for physics beyond the Standard Model. The objective of the present study is to search for the 129Xe EDM at a level of 10-28 ecm, beyond the current upper limit. In this experiment, an active-feedback nuclear spin maser is employed to achieve a precision measurement. Systematic instability sets a limit on the precision in our study. Co-magnetometry using 3He spin maser was incorporated into the maser system to eliminate the frequency drift caused by magnetic field fluctuations. Moreover, a double-cell geometry with linearly polarized laser was introduced to reduce frequency drifts arising from contact interactions with polarized Rb atoms. Having integrated these improvements, the 3He/129Xe dual spin maser was successfully operated. In the presentation, recent progress will be reported, including an analysis of spin maser frequencies, a study of electrode designs, and an estimation of possible systematic uncertainties.
Sensing of single nuclear spins in random thermal motion with proximate nitrogen-vacancy centers
Bruderer, M.; Fernández-Acebal, P.; Aurich, R.; Plenio, M. B.
2016-03-01
Nitrogen-vacancy (NV) centers in diamond have emerged as valuable tools for sensing and polarizing spins. Motivated by potential applications in chemistry, biology, and medicine, we show that NV-based sensors are capable of detecting single spin targets even if they undergo diffusive motion in an ambient thermal environment. Focusing on experimentally relevant diffusion regimes, we derive an effective model for the NV-target interaction, where parameters entering the model are obtained from numerical simulations of the target motion. The practicality of our approach is demonstrated by analyzing two realistic experimental scenarios: (i) time-resolved sensing of a fluorine nuclear spin bound to an N-heterocyclic carbene-ruthenium (NHC-Ru) catalyst that is immobilized on the diamond surface and (ii) detection of an electron spin label by an NV center in a nanodiamond, both attached to a vibrating chemokine receptor in thermal motion. We find in particular that the detachment of a fluorine target from the NHC-Ru carrier molecule can be monitored with a time resolution of a few seconds.
Theoretical approaches to control spin dynamics in solid-state nuclear magnetic resonance
Indian Academy of Sciences (India)
Eugene Stephane Mananga
2015-12-01
This article reviews theoretical approaches for controlling spin dynamics in solid-state nuclear magnetic resonance. We present fundamental theories in the history of NMR, namely, the average Hamiltonian and Floquet theories. We also discuss emerging theories such as the Fer and Floquet-Magnus expansions. These theories allow one to solve the time-dependent Schrodinger equation, which is still the central problem in spin dynamics of solid-state NMR. Examples from the literature that highlight several applications of these theories are presented, and particular attention is paid to numerical integrators and propagator operators. The problem of time propagation calculated with Chebychev expansion and the future development of numerical directions with the Cayley transformation are considered. The bibliography includes 190 references.
Impact of hadronic and nuclear corrections on global analysis of spin-dependent parton distributions
Energy Technology Data Exchange (ETDEWEB)
Jimenez-Delgado, Pedro [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Accardi, Alberto [Hampton University, Hampton, VA (United States); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Melnitchouk, Wally [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
2014-02-01
We present the first results of a new global next-to-leading order analysis of spin-dependent parton distribution functions from the most recent world data on inclusive polarized deep-inelastic scattering, focusing in particular on the large-x and low-Q^2 regions. By directly fitting polarization asymmetries we eliminate biases introduced by using polarized structure function data extracted under nonuniform assumptions for the unpolarized structure functions. For analysis of the large-x data we implement nuclear smearing corrections for deuterium and 3He nuclei, and systematically include target mass and higher twist corrections to the g_1 and g_2 structure functions at low Q^2. We also explore the effects of Q^2 and W^2 cuts in the data sets, and the potential impact of future data on the behavior of the spin-dependent parton distributions at large x.
EDM measurement in 129Xe atom using dual active feedback nuclear spin maser
Sato, T.; Ichikawa, Y.; Ohtomo, Y.; Sakamoto, Y.; Kojima, S.; Funayama, C.; Suzuki, T.; Chikamori, M.; Hikota, E.; Tsuchiya, M.; Furukawa, T.; Yoshimi, A.; Bidinosti, C. P.; Ino, T.; Ueno, H.; Matsuo, Y.; Fukuyama, T.; Asahi, K.
2015-04-01
The technique of an active nuclear spin maser is adopted in the search for electric dipole moment in a diamagnetic atom 129Xe. In order to reduce systematic uncertainties arising from long-term drifts of the external magnetic field and from the contact interaction between longitudinal polarized Rb atoms and 129Xe spin, a 3He comagnetometer with a double-cell geometry was employed. The remaining shift, which turned out to show some correlation with the cell temperature, was mitigated by stabilizing the cell temperature. As a result, the frequency drift of the 129Xe maser was reduced from 12 mHz to 700 μHz, and the determination precision of frequency of 8.7 nHz was obtained for a 2×104 s measurement time using the double-cell geometry cell.
EDM measurement in 129Xe atom using dual active feedback nuclear spin maser
International Nuclear Information System (INIS)
The technique of an active nuclear spin maser is adopted in the search for electric dipole moment in a diamagnetic atom 129Xe. In order to reduce systematic uncertainties arising from long-term drifts of the external magnetic field and from the contact interaction between longitudinal polarized Rb atoms and 129Xe spin, a 3He comagnetometer with a double-cell geometry was employed. The remaining shift, which turned out to show some correlation with the cell temperature, was mitigated by stabilizing the cell temperature. As a result, the frequency drift of the 129Xe maser was reduced from 12 mHz to 700 μHz, and the determination precision of frequency of 8.7 nHz was obtained for a 2×104 s measurement time using the double-cell geometry cell
EDM measurement in {sup 129}Xe atom using dual active feedback nuclear spin maser
Energy Technology Data Exchange (ETDEWEB)
Sato, T., E-mail: sato@yap.nucl.ap.titech.ac.jp [Tokyo Institute of Technology, Department of Physics (Japan); Ichikawa, Y. [RIKEN Nishina Center (Japan); Ohtomo, Y.; Sakamoto, Y.; Kojima, S.; Funayama, C.; Suzuki, T.; Chikamori, M.; Hikota, E.; Tsuchiya, M. [Tokyo Institute of Technology, Department of Physics (Japan); Furukawa, T. [Tokyo Metropolitan University, Department of Physics (Japan); Yoshimi, A. [Okayama University, Research Core for Extreme Quantum World (Japan); Bidinosti, C. P. [University of Winnipeg, Department Physics (Canada); Ino, T. [Institute of Material Structure Science, KEK (Japan); Ueno, H. [RIKEN Nishina Center (Japan); Matsuo, Y. [Hosei University, Department of Advanced Sciences (Japan); Fukuyama, T. [Osaka University, RCNP (Japan); Asahi, K. [Tokyo Institute of Technology, Department of Physics (Japan)
2015-04-15
The technique of an active nuclear spin maser is adopted in the search for electric dipole moment in a diamagnetic atom {sup 129}Xe. In order to reduce systematic uncertainties arising from long-term drifts of the external magnetic field and from the contact interaction between longitudinal polarized Rb atoms and {sup 129}Xe spin, a {sup 3}He comagnetometer with a double-cell geometry was employed. The remaining shift, which turned out to show some correlation with the cell temperature, was mitigated by stabilizing the cell temperature. As a result, the frequency drift of the {sup 129}Xe maser was reduced from 12 mHz to 700 μHz, and the determination precision of frequency of 8.7 nHz was obtained for a 2×10{sup 4} s measurement time using the double-cell geometry cell.
Electron-Mediated Nuclear-Spin Interactions Between Distant NV Centers
Bermudez, A; Plenio, M B; Retzker, A
2011-01-01
We propose a scheme enabling controlled quantum coherent interactions between separated nitrogen-vacancy centers in diamond in the presence of strong magnetic fluctuations. The proposed scheme couples nuclear qubits employing the magnetic dipole-dipole interaction between the electron spins and, crucially, benefits from the suppression of the effect of environmental magnetic field fluctuations thanks to a strong microwave driving. This scheme provides a basic building block for a full-scale quantum information processor or quantum simulator based on solid-state technology.
Spin dipole nuclear matrix elements for double beta decay nuclei by charge-exchange reactions
Ejiri, H
2016-01-01
Spin dipole (SD) strengths for double beta-decay (DBD) nuclei were studied experimentally for the first time by using measured cross sections of (3He,t) charge exchange reactions (CERs). Then SD nuclear matrix elements (NMEs) for low-lying 2- states were derived from the experimental SD strengths by referring to the experimental GT (Gamow-Teller) and F (Fermi) strengths. They are consistent with the empirical SD NMEs based on the quasi-particle model with the empirical effective SD coupling constant. The CERs are used to evaluate the SD NME, which is associated with one of the major components of the neutrino-less DBD NME.
Robin, Caroline
2016-01-01
A new theoretical approach to spin-isospin excitations in open-shell nuclei is presented. The developed method is based on the relativistic meson-exchange nuclear Lagrangian of Quantum Hadrodynamics and extends the response theory for superfluid nuclear systems beyond relativistic quasiparticle random phase approximation in the proton-neutron channel (pn-RQRPA). The coupling between quasiparticle degrees of freedom and collective vibrations (phonons) introduces a time-dependent effective interaction, in addition to the exchange of pion and $\\rho$-meson taken into account without retardation. The time-dependent contributions are treated in the resonant time-blocking approximation, in analogy to previously developed relativistic quasiparticle time blocking approximation (RQTBA) in the neutral (non-isospin-flip) channel. The new method is called proton-neutron RQTBA (pn-RQTBA) and applied to Gamow-Teller resonance in a chain of neutron-rich Nickel isotopes $^{68-78}$Ni. A strong fragmentation of the resonance al...
Dissipatively driven entanglement of two nuclear spin ensembles in a double quantum dot
Energy Technology Data Exchange (ETDEWEB)
Schuetz, Martin J.A.; Kessler, Eric M.; Cirac, Juan Ignacio; Giedke, Geza [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching (Germany)
2013-07-01
Typically, quantum information schemes have been discussed in the context of isolated many-body systems subject to unitary dynamics. Here, dissipation has been identified as a mechanism that corrupts the useful quantum properties of the system under study. Recently, however, with the advent of novel ideas such as dissipative engineering, a paradigm shift could be observed in quantum physics. More and more approaches actively utilize dissipation as a driving force behind the emergence of coherent quantum phenomena. In this spirit, we propose a transport scheme for an electrically defined double quantum dot in which the two nuclear ensembles in the host environment are actively pumped into an entangled target state. Based on a self-consistent Holstein-Primakoff approximation, we derive an effective quantum master equation for the nuclear spins which features an unique entangled steady state; accordingly, long lasting entanglement is created deterministically. Prospects for the experimental realization of this proposal are briefly discussed.
Energy Technology Data Exchange (ETDEWEB)
Schmid, K.W.; Gruemmer, F.; Faessler, A.
1984-01-01
In the present paper a general survey of the mathematical formalism for microscopic nuclear structure calculations in configuration spaces consisting of arbitrary spin- and number-projected Hartree-Fock-Bogoliubov--type quasiparticle determinants is given. On the basis of this formalism, various levels of approximation are then discussed. These lead to a number of microscopic nuclear structure models in between the standard Hartree-Fock-Bogoliubov theory and the complete diagonalization of a given effective many nucleon Hamiltonian. For all these models variational equations are derived and possibilities for their numerical application are estimated. The second part of the present series of two papers will then present initial results of the applications of the simplest of these models to several nuclei in various mass regions.
Fast all-optical nuclear spin echo technique based on EIT
Walther, Andreas; Nilsson, Adam N.; Li, Qian; Rippe, Lars; Kröll, Stefan
2016-08-01
We demonstrate an all-optical Raman spin echo technique, using electromagnetically induced transparency (EIT) to create the pulses required for a spin echo sequence: initialization, pi-rotation, and readout. The first pulse of the sequence induces coherence directly from a mixed state, and the technique is used to measure the nuclear spin coherence of an inhomogeneously broadened ensemble of rare-earth ions (Pr3 +) in a crystal. The rephasing pi-rotation is shown to offer an advantage of combining the rephasing action with the operation of a phase gate, particularly useful in e.g. dynamic decoupling sequences. In contrast to many previous experiments the sequence does not require any preparatory hole burning, which greatly shortens the total duration of the sequence. The effect of the different pulses is characterized by quantum state tomography and compared with simulations. We demonstrate two applications of the technique: compensating the magnetic field across our sample by monitoring T 2 reductions from stray magnetic fields, and measuring coherence times at temperatures up to 11 K, where standard preparation techniques are difficult to implement. We explore the potential of the technique, in particular for systems with much shorter T 2, and other possible applications.
Cardona-Serra, Salvador; Escalera-Moreno, Luis; Baldoví, José J; Gaita-Ariño, Alejandro; Clemente-Juan, Juan M; Coronado, Eugenio
2016-05-15
SIMPRE is a fortran77 code which uses an effective electrostatic model of point charges to predict the magnetic behavior of rare-earth-based mononuclear complexes. In this article, we present SIMPRE1.2, which now takes into account two further phenomena. First, SIMPRE now considers the hyperfine and quadrupolar interactions within the rare-earth ion, resulting in a more complete and realistic set of energy levels and wave functions. Second, and to widen SIMPRE's predictive capabilities regarding potential molecular spin qubits, it now includes a routine that calculates an upper-bound estimate of the decoherence time considering only the dipolar coupling between the electron spin and the surrounding nuclear spin bath. Additionally, SIMPRE now allows the user to introduce the crystal field parameters manually. Thus, we are able to demonstrate the new features using as examples (i) a Gd-based mononuclear complex known for its properties both as a single ion magnet and as a coherent qubit and (ii) an Er-based mononuclear complex. © 2016 Wiley Periodicals, Inc. PMID:26833799
WURST-QCPMG sequence and "spin-lock" in 14N nuclear quadrupole resonance
Gregorovič, Alan; Apih, Tomaž
2013-08-01
14N nuclear quadrupole resonance (NQR) is a promising method for the analysis of pharmaceuticals or for the detection of nitrogen based illicit compounds, but so far, the technique is still not widely used, mostly due to the very low sensitivity. This problem is already acute in the preliminary NQR stage, when a compound is being examined for the first time and the NQR frequencies are being searched for, by scanning a wide frequency range step-by-step. In the present work, we experimentally show how to increase the efficiency of this initial stage by using a combination of a wideband excitation achieved with frequency swept pulses (WURST) and a "spin-lock" state obtained with a quadrupolar-CPMG (QCPMG) sequence. In the first part we show that WURST pulses provide a much larger excitation bandwidth compared to common rectangular pulses. This increased bandwidth allows to increase the frequency step and reduces the total number of steps in a scanning stage. In the second part we show that the "spin-lock" decay time T2eff obtained with the WURST-QCPMG combination is practically identical with the T2eff obtained with the most common "spin-lock" sequence, the SLSE, despite a very different nature and length of excitation pulses. This allows for a substantial S/N increase through echo averaging in every individual step and really allows to exploit all the advantages of the wider excitation in the NQR frequency scanning stage. Our experimental results were obtained on a sample of trinitrotoluene, but identical behavior is expected for all compounds where a "spin-lock" state can be created.
Thurber, Kent R.; Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert
2013-01-01
We describe an apparatus for solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS) at 20-25 K and 9.4 Tesla. The MAS NMR probe uses helium to cool the sample space and nitrogen gas for MAS drive and bearings, as described earlier [1], but also includes a corrugated waveguide for transmission of microwaves from below the probe to the sample. With a 30 mW circularly polarized microwave source at 264 GHz, MAS at 6.8 kHz, and 21 K sample temperature, greater than 25-fold enhancements of cross-polarized 13C NMR signals are observed in spectra of frozen glycerol/water solutions containing the triradical dopant DOTOPA-TEMPO when microwaves are applied. As demonstrations, we present DNP-enhanced one-dimensional and two-dimensional 13C MAS NMR spectra of frozen solutions of uniformly 13C-labeled L-alanine and melittin, a 26-residue helical peptide that we have synthesized with four uniformly 13C-labeled amino acids.
Hyperpolarization of 29Si by Resonant Nuclear Spin Transfer from Optically Hyperpolarized 31P Donors
Dluhy, Phillip; Salvail, Jeff; Saeedi, Kamyar; Thewalt, Mike; Simons, Stephanie
2014-03-01
Recent developments in nanomedicine have allowed nanoparticles of silicon containing hyperpolarized 29Si to be imaged in vivo using magnetic resonance imaging. The extremely long relaxation times and isotropy of the Si lattice make polarized 29Si isotopes ideal for these sorts of imaging methods. However, one of the major difficulties standing in the path of widespread adoption of these techniques is the slow rate at which the 29Si is hyperpolarized and the limited maximum hyperpolarization achievable. In this talk, I will describe an effective method for hyperpolarization of the 29Si isotopes using resonant optical pumping of the donor bound exciton transitions to polarize the 31P donor nuclei, and a choice of static magnetic field that conserves energy during spin flip flops between donor nuclear and 29Si spins to facilitate diffusion of this polarization. Using this method, we are able to polarize greater than 10% of the 29Si centers in 64 hours without seeing saturation of the 29Si polarization.
Quantum non demolition measurement of a single nuclear spin in a room temperature solid
International Nuclear Information System (INIS)
The measurement process and its interpretation are in the focus of quantum mechanics since its early days. Today's ability to isolate single quantum objects allows experimental demonstration of former ''gedankenexperiments'' like measurement induced quantum state collaps. Rapidly growing quantum technologies explore fundamental aspects of measurements in quantum computing, however for solid state systems such experiments require operation at very low temperatures. Here we show that projective quantum measurement can be performed on a single nuclear spin in diamond under ambient conditions. Using quantum non demolition (QND) readout we are able to detect quantum jumps and the quantum Zeno effect emphasising the addressability of fundamental questions of quantum mechanics in solids. Single shot measurements with fidelities exceeding 0.9 enable efficient state initialization, quantum error correction and entanglement pumping that is crucial for quantum information processing including measurement based schemes and distributed quantum networks.
Second-Scale Nuclear Spin Coherence Time of Trapped Ultracold $^{23}$Na$^{40}$K Molecules
Park, Jee Woo; Loh, Huanqian; Will, Sebastian A; Zwierlein, Martin W
2016-01-01
Coherence, the stability of the relative phase between quantum states, lies at the heart of quantum mechanics. Applications such as precision measurement, interferometry, and quantum computation are enabled by physical systems that have quantum states with robust coherence. With the creation of molecular ensembles at sub-$\\mu$K temperatures, diatomic molecules have become a novel system under full quantum control. Here, we report on the observation of stable coherence between a pair of nuclear spin states of ultracold fermionic NaK molecules in the singlet rovibrational ground state. Employing microwave fields, we perform Ramsey spectroscopy and observe coherence times on the scale of one second. This work opens the door for the exploration of single molecules as a versatile quantum memory. Switchable long-range interactions between dipolar molecules can further enable two-qubit gates, allowing quantum storage and processing in the same physical system. Within the observed coherence time, $10^4$ one- and two-...
International Nuclear Information System (INIS)
Multistep direct reactions 40Ca(p, p'x) at 392 MeV and 40Ca(p, nx) at 346 MeV are analyzed including up to three-step process. The double differential inclusive cross sections and the complete set of spin transfer coefficients Dij are calculated by the semiclassical distorted wave model and compared with experimental data. We use single particle wave functions in a Woods-Saxon potential incorporating the Wigner transform of a one-body density matrix and also introduce a phenomenological effective mass m* of a nucleon in the target. Analysis of Dij in terms of an effective interaction in nuclear medium is also done. (author)
International Nuclear Information System (INIS)
The process of licensing nuclear power plants for operation consists of mandatory steps featuring detailed examination of the instrumentation and control system. Significant changes were introduced by the operator in the process of designing and producing 1400 MWe pressurized water reactor safety systems and, in particular, in the case of the Digital Integrated Protection System, (French abbreviation SPIN). The methodology applied by the Institute of Protection and Nuclear Safety (IPSN) to examine the software of this system is described. It consists of the methods used by the manufacturer to develop SPIN software for the 1400 MWe PWRs, and the approach adopted by the IPSN to evaluate SPIN safety softwares of the protection system for the N4 series of reactors. (R.P.). 2 refs
Nisson, D. M.; Curro, N. J.
2016-07-01
In recent years there has been increasing interest in materials with strong spin-orbit coupling (SOC). Nuclear magnetic resonance is a valuable microscopic probe of such systems because of the hyperfine interactions between the nuclear spins and the electron degrees of freedom. In materials with weak SOC the NMR Knight shift contains two contributions: one from the electron orbital susceptibility and the other from the electron spin susceptibility. These contributions can be separated by plotting the Knight shift versus the bulk susceptibility and extracting the slope and intercept. Here we examine the case where the SOC is non-negligible, in which case the slope and intercept are no longer simply related to these two contributions. These results have important implications for NMR studies of heavy fermions, as well as 4d and 5d systems.
Orlinkskii, S.B.; Borovykh, I.V.; Zielke, V.; Steinhoff, H.J.
2007-01-01
The applicability of spin labels to study membrane proteins by high-frequency electron nuclear double resonance spectroscopy is demonstrated. With the use of bacteriorhodopsin embedded in a lipid membrane as an example, the spectra of protons of neighboring amino acids are recorded, electric field g
Nuclear spin imaging with hyperpolarized nuclei created by brute force method
Tanaka, Masayoshi; Kunimatsu, Takayuki; Fujiwara, Mamoru; Kohri, Hideki; Ohta, Takeshi; Utsuro, Masahiko; Yosoi, Masaru; Ono, Satoshi; Fukuda, Kohji; Takamatsu, Kunihiko; Ueda, Kunihiro; Didelez, Jean-P.; Prossati, Giorgio; de Waard, Arlette
2011-05-01
We have been developing a polarized HD target for particle physics at the SPring-8 under the leadership of the RCNP, Osaka University for the past 5 years. Nuclear polarizaton is created by means of the brute force method which uses a high magnetic field (~17 T) and a low temperature (~ 10 mK). As one of the promising applications of the brute force method to life sciences we started a new project, "NSI" (Nuclear Spin Imaging), where hyperpolarized nuclei are used for the MRI (Magnetic Resonance Imaging). The candidate nuclei with spin ½hslash are 3He, 13C, 15N, 19F, 29Si, and 31P, which are important elements for the composition of the biomolecules. Since the NMR signals from these isotopes are enhanced by orders of magnitudes, the spacial resolution in the imaging would be much more improved compared to the practical MRI used so far. Another advantage of hyperpolarized MRI is that the MRI is basically free from the radiation, while the problems of radiation exposure caused by the X-ray CT or PET (Positron Emission Tomography) cannot be neglected. In fact, the risk of cancer for Japanese due to the radiation exposure through these diagnoses is exceptionally high among the advanced countries. As the first step of the NSI project, we are developing a system to produce hyperpolarized 3He gas for the diagnosis of serious lung diseases, for example, COPD (Chronic Obstructive Pulmonary Disease). The system employs the same 3He/4He dilution refrigerator and superconducting solenoidal coil as those used for the polarized HD target with some modification allowing the 3He Pomeranchuk cooling and the following rapid melting of the polarized solid 3He to avoid the depolarization. In this report, the present and future steps of our project will be outlined with some latest experimental results.
International Nuclear Information System (INIS)
Nuclear spin-off has at least two dimensions. It may provide benefits to the society such as enlarge knowledge base, strengthen infrastructure and benefit technology development. Besides this, to emphasize that some useful technologies elapsed from nuclear activities can affect favorably the public opinion about nuclear energy. In this paper is described a technology developed initially by the Rockwell Int. company in the USA more than thirty years ago to solve some problems of nuclear fuel cycle wastes. For different reasons the technology was not employed. In the last years the interest in the technology was renewed and IPEN has developed his version of the method applicable mainly to the safe degradation of hazardous wastes. This study was motivated by the world interest in the development of advanced processes of waste decomposition, due to the need of safer decomposition processes, particularly for the POPs - persistent organic pollutants and particularly for the organ chlorides. A tendency observed at several countries is the adoption of progressively more demanding legislation for the atmospheric emissions, resultants of the waste decomposition processes. The suitable final disposal of hazardous organic wastes such as PCBs (polychlorinated biphenyls), pesticides, herbicides and hospital residues constitutes a serious problem. In some point of their life cycles, these wastes should be destroyed, in reason of the risk that they represent for the human being, animals and plants. The process involves using a chemical reactor containing molten salts, sodium carbonate or some alkaline carbonates mixtures to decompose the organic waste. The decomposition is performed by submerged oxidation and the residue is injected below the surface of a turbulent salt bath along with the oxidizing agent. Decomposition of halogenated compounds, among which some pesticides, is particularly effective in molten salts. The process presents properties such as intrinsically safe
Fractionated Mercury Isotopes in Fish: The Effects of Nuclear Mass, Spin, and Volume
Das, R.; Odom, A. L.
2007-12-01
.3, and thus more than one mass-independent isotope effect is inferred. MIF of mercury can be caused by the nuclear volume effect. Schauble, 2007 has calculated nuclear volume fractionation scaling factors for a number of common mercury chemical species in equilibrium with Hg° vapor. From his calculations the nuclear field shift effect is larger in Δ199Hg than in Δ201Hg by approximately a factor of two. The predominant mercury chemical species in fish is methylmercury cysteine. From the experimental studies of Buchachenko and others (2004) on the reaction of methylmercury chloride with creatine kinase it seems reasonable to predicted that the thiol functional groups of cysteine gets enriched in 199Hg and 201Hg. Here the magnetic isotope effect (MIE) produces a kinetic partial separation of isotopes with non-zero nuclear spin quantum numbers from the even-N isotopes. The ratio of enrichment of Δ201Hg /Δ199Hg is predicted from theory to be 1.11, which is the ratio of the magnetic moments of 199Hg and 201Hg. Because mercury possesses two odd-N isotopes, it is possible to detect and evaluate the effects of two distinct, mass-independent isotope fractionating processes. From the data obtained on fish samples, we can deconvolute the contributions of the isotope effects of nuclear mass, spin and volume. For these samples the role of spin or the magnetic isotope effect is the most dominant.
The Decoherence of the Electron Spin and Meta-Stability of 13C Nuclear Spins in Diamond
Peter Crompton
2011-01-01
Following the recent successful experimental manipulation of entangled 13C atoms on the surface of Diamond, we calculate the decoherence of the electron spin in Nitrogen Vacancy NV centers of Diamond via a nonperturbative treatment of the time-dependent Greens function of a Central-Spin model in order to identify the Replica Symmetry Breaking mechanism associated with intersystem mixing between the ms = 0 sublevel of the 3A2 and 1A1 states of the NV− centers, which we identify as mediated via...
Schmiedt, Hanno; Jensen, Per; Schlemmer, Stephan
2016-08-01
In modern physics and chemistry concerned with many-body systems, one of the mainstays is identical-particle-permutation symmetry. In particular, both the intra-molecular dynamics of a single molecule and the inter-molecular dynamics associated, for example, with reactive molecular collisions are strongly affected by selection rules originating in nuclear-permutation symmetry operations being applied to the total internal wavefunctions, including nuclear spin, of the molecules involved. We propose here a general tool to determine coherently the permutation symmetry and the rotational symmetry (associated with the group of arbitrary rotations of the entire molecule in space) of molecular wavefunctions, in particular the nuclear-spin functions. Thus far, these two symmetries were believed to be mutually independent and it has even been argued that under certain circumstances, it is impossible to establish a one-to-one correspondence between them. However, using the Schur-Weyl duality theorem we show that the two types of symmetry are inherently coupled. In addition, we use the ingenious representation-theory technique of Young tableaus to represent the molecular nuclear-spin degrees of freedom in terms of well-defined mathematical objects. This simplifies the symmetry classification of the nuclear wavefunction even for large molecules. Also, the application to reactive collisions is very straightforward and provides a much simplified approach to obtaining selection rules.
Schmiedt, Hanno; Jensen, Per; Schlemmer, Stephan
2016-08-21
In modern physics and chemistry concerned with many-body systems, one of the mainstays is identical-particle-permutation symmetry. In particular, both the intra-molecular dynamics of a single molecule and the inter-molecular dynamics associated, for example, with reactive molecular collisions are strongly affected by selection rules originating in nuclear-permutation symmetry operations being applied to the total internal wavefunctions, including nuclear spin, of the molecules involved. We propose here a general tool to determine coherently the permutation symmetry and the rotational symmetry (associated with the group of arbitrary rotations of the entire molecule in space) of molecular wavefunctions, in particular the nuclear-spin functions. Thus far, these two symmetries were believed to be mutually independent and it has even been argued that under certain circumstances, it is impossible to establish a one-to-one correspondence between them. However, using the Schur-Weyl duality theorem we show that the two types of symmetry are inherently coupled. In addition, we use the ingenious representation-theory technique of Young tableaus to represent the molecular nuclear-spin degrees of freedom in terms of well-defined mathematical objects. This simplifies the symmetry classification of the nuclear wavefunction even for large molecules. Also, the application to reactive collisions is very straightforward and provides a much simplified approach to obtaining selection rules. PMID:27544099
Schmiedt, Hanno; Jensen, Per; Schlemmer, Stephan
2016-08-21
In modern physics and chemistry concerned with many-body systems, one of the mainstays is identical-particle-permutation symmetry. In particular, both the intra-molecular dynamics of a single molecule and the inter-molecular dynamics associated, for example, with reactive molecular collisions are strongly affected by selection rules originating in nuclear-permutation symmetry operations being applied to the total internal wavefunctions, including nuclear spin, of the molecules involved. We propose here a general tool to determine coherently the permutation symmetry and the rotational symmetry (associated with the group of arbitrary rotations of the entire molecule in space) of molecular wavefunctions, in particular the nuclear-spin functions. Thus far, these two symmetries were believed to be mutually independent and it has even been argued that under certain circumstances, it is impossible to establish a one-to-one correspondence between them. However, using the Schur-Weyl duality theorem we show that the two types of symmetry are inherently coupled. In addition, we use the ingenious representation-theory technique of Young tableaus to represent the molecular nuclear-spin degrees of freedom in terms of well-defined mathematical objects. This simplifies the symmetry classification of the nuclear wavefunction even for large molecules. Also, the application to reactive collisions is very straightforward and provides a much simplified approach to obtaining selection rules.
Robin, Caroline; Litvinova, Elena
2016-07-01
A new theoretical approach to spin-isospin excitations in open-shell nuclei is presented. The developed method is based on the relativistic meson-exchange nuclear Lagrangian of Quantum Hadrodynamics and extends the response theory for superfluid nuclear systems beyond relativistic quasiparticle random phase approximation in the proton-neutron channel (pn-RQRPA). The coupling between quasiparticle degrees of freedom and collective vibrations (phonons) introduces a time-dependent effective interaction, in addition to the exchange of pion and ρ -meson taken into account without retardation. The time-dependent contributions are treated in the resonant time-blocking approximation, in analogy to the previously developed relativistic quasiparticle time-blocking approximation (RQTBA) in the neutral (non-isospin-flip) channel. The new method is called proton-neutron RQTBA (pn-RQTBA) and is applied to the Gamow-Teller resonance in a chain of neutron-rich nickel isotopes 68-78Ni . A strong fragmentation of the resonance along with quenching of the strength, as compared to pn-RQRPA, is obtained. Based on the calculated strength distribution, beta-decay half-lives of the considered isotopes are computed and compared to pn-RQRPA half-lives and to experimental data. It is shown that a considerable improvement of the half-life description is obtained in pn-RQTBA because of the spreading effects, which bring the lifetimes to a very good quantitative agreement with data.
Energy Technology Data Exchange (ETDEWEB)
Grohmann, Thomas
2012-05-31
In this thesis the wave packet dynamics of nuclear spin isomers of polyatomic molecules after interaction with static and time-dependent magnetic fields and moderate intense nonresonant laser pulses is investigated. In particular, the process of inducing (internal) molecular rotation as well as alignment of molecules by manipulating their rotational or rotational-torsional degrees of freedom is studied. In the first part of the thesis all theoretical concepts for identifying nuclear spin isomers and for describing their quantum dynamics will be discussed. Especially the symmetrization postulate and themolecular symmetry group will be introduced and illustrated for some examples of molecules. These concepts will be extended to the case of identifying nuclear spin isomers in the presence of an external field. In the second part it is shown for nitromethane that magnetic fields are able to induce unidirectional rotations in opposite directions for different nuclear spin isomers of molecules containing methyl groups if the dipolar interaction is included. Additionally, it is demonstrated that different nuclear spin isomers of a chemical compound may show different alignment after the interaction with a moderate intense laser pulse. As shown for the rigid symmetric top propadien and the rigid asymmetric tops ethene and analogues, distinct pairs of nuclear spin isomers show at certain points in time a complementary behavior: while one isomer is showing alignment the partner isomer is showing anti-alignment. Moreover, it is illustrated that not every nuclear spin isomer can be aligned equally efficient. The alignment of non-rigid molecules is considered as well. As an example for a molecule with feasible torsion in the electronic ground state, the alignment of diboron tetrafluoride is investigated. It becomes apparent that not only rotational but also the torsional dynamics of the molecules is nuclear spin selective; different nuclear spin isomers have at distinct points
Energy Technology Data Exchange (ETDEWEB)
Soubies, B.; Henry, J.Y.; Le Meur, M. [and others
1995-04-01
1300 MWe pressurised water reactors (PWRs), like the 1400 MWe reactors, operate with microprocessor-based safety systems. This is particularly the case for the Digital Integrated Protection System (SPIN), which trips the reactor in an emergency and sets in action the safeguard functions. The softwares used in these systems must therefore be highly dependable in the execution of their functions. In the case of SPIN, three players are working at different levels to achieve this goal: the protection system manufacturer, Merlin Gerin; the designer of the nuclear steam supply system, Framatome; the operator of the nuclear power plants, Electricite de France (EDF), which is also responsible for the safety of its installations. Regulatory licenses are issued by the French safety authority, the Nuclear Installations Safety Directorate (French abbreviation DSIN), subsequent to a successful examination of the technical provisions adopted by the operator. This examination is carried out by the IPSN and the standing group on nuclear reactors. This communication sets out: the methods used by the manufacturer to develop SPIN software for the 1400 MWe PWRs (N4 series); the approach adopted by the IPSN to evaluate the safety software of the protection system for the N4 series of reactors.
Clevenson, Hannah; Chen, Edward; Dolde, Florian; Teale, Carson; Englund, Dirk; Braje, Danielle
2016-05-01
We report on detailed studies of electronic and nuclear spin states in the diamond nitrogen vacancy (NV) center under moderate transverse magnetic fields. We numerically predict and experimentally verify a previously unobserved NV ground state hyperfine anti-crossing occurring at magnetic bias fields as low as tens of Gauss - two orders of magnitude lower than previously reported hyperfine anti-crossings at ~ 510 G and ~ 1000 G axial magnetic fields. We then discuss how this regime can be optimized for magnetometry and other sensing applications and propose a method for how the nitrogen-vacancy ground state Hamiltonian can be manipulated by small transverse magnetic fields to polarize the nuclear spin state. Acknowlegement: The Lincoln Laboratory portion of this work is sponsored by the Assistant Secretary of Defense for Research & Engineering under Air Force Contract #FA8721-05-C-0002. Opinions, interpretations, conclusions and recommendations are those of the authors and are not necessarily endorsed by the United States Government.
Experimental Investigation of Nuclear Spin Conversion in Interstellar Pre-Cometary Ices
Broadhurst, C. L.; Mumma, M. J.
1992-07-01
High resolution infrared spectroscopy of the H2O upsilon(sub)3 band in Comets P/Halley and Wilson has permitted measurement of individual rotational line intensities (Larson et al. 1989). Mumma et al. (1988) suggested that cosmogonic information is preserved in the relative abundances of the nuclear spin species. The H2O molecule is organized into ortho and para species. In order that the total wave function remain symmetric with respect to H atom exchange, o-species have only asymmetric rotational levels, while p-species have only symmetric levels. The lowest ortho level lies 24 cm^-1 (34 degrees K) above the lowest para level, so the ortho/para ratio will be temperature dependent. Above 60 degrees K, o/p achieves the constant statistical equilibrium value of 3/1. Spin species conversion is prohibited by collisional and radiative processes, and requires a strong nonuniform magnetic field. It is hypothesized that cometary water began as a thin layer of ice condensed on grains in cold interstellar molecular clouds. This ice was subject to UV radiation Wilson, might be expected to show a statistically equilibrated o/p, whereas a short-period comet, such as P/Halley, might show o/p characteristic of its formation. It also appears that D/H in cometary ice was established in interstellar cloud cores, and did not later equilibrate with nebular gas. D/H for Comet P/Halley lies in the range 6-48 x 10^-5 (Eberhardt et al. 1987), much higher than the diffuse ISM, protosolar, Jupiter, and Saturn values (0.5-3.6 x 10^-5). The cometary range is comparable to D/H for Earth (16 x 10^-5) as well as Uranus, Neptune, and Titan, indicating that these bodies acquired their hydrogen in the form of ices as opposed to nebular H2. Similarly, the D/H range for carbonaceous and ordinary chondrites is high (8-105 x 10^-5), and is thought to reflect incorporation of insterstellar material into meteorites (Zinner, 1988). We have developed a novel experimental apparatus to study nuclear spin
High dynamic range magnetometry with a single nuclear spin in diamond
Energy Technology Data Exchange (ETDEWEB)
Waldherr, Gerald; Beck, Johannes; Neumann, Philipp; Nitsche, Matthias; Wrachtrup, Joerg [3. Physikalisches Institut, Universitaet Stuttgart, 70569 Stuttgart (Germany); Said, Ressa S. [Institut fuer Quanten-Informationsverarbeitung, Universitaet Ulm, 89081 Ulm (Germany); Twamley, Jason [Centre for Engineered Quantum Systems, Faculty of Science, Macquarie University, Sydney (Australia); Jelezko, Fedor [Institut fuer Quantenoptik, Universitaet Ulm, 89073 Ulm (Germany)
2012-07-01
Sensors based on the nitrogen-vacancy (NV) defect in diamond are being developed to measure weak magnetic and electric fields at nanoscale. However, such sensors rely on measurements of a shift in the Lamor frequency of the defect, so an accumulation of quantum phase causes the measurement signal to exhibit a periodic modulation. This means that the measurement time is either restricted to half of one oscillation period, which limits accuracy, or that the magnetic field range must be known in advance. Moreover, the precision increases only slowly, as T{sup -0.5}, with the measurement time T. We implement a quantum phase estimation algorithm on a single nuclear spin in diamond to combine both high sensitivity and high dynamic range. By achieving a scaling of the precision with time to T{sup -0.85}, we improve the sensitivity by a factor of 7.4, for an accessible field range of 16 mT, or alternatively, we improve the dynamic range by a factor of 130 for a sensitivity of 2.5 {mu}T/Hz{sup 0.5}. These methods are applicable to a variety of field detection schemes, and do not require entanglement.
Spurious finite-size instabilities in nuclear energy density functionals: Spin channel
Pastore, A.; Tarpanov, D.; Davesne, D.; Navarro, J.
2015-08-01
Background: It has been recently shown that some Skyrme functionals can lead to nonconverging results in the calculation of some properties of atomic nuclei. A previous study has pointed out a possible link between these convergence problems and the appearance of finite-size instabilities in symmetric nuclear matter (SNM) around saturation density. Purpose: We show that the finite-size instabilities not only affect the ground-state properties of atomic nuclei, but they can also influence the calculations of vibrational excited states in finite nuclei. Method: We perform systematic fully-self consistent random phase approximation (RPA) calculations in spherical doubly magic nuclei. We employ several Skyrme functionals and vary the isoscalar and isovector coupling constants of the time-odd term s .Δ s . We determine critical values of these coupling constants beyond which the RPA calculations do not converge because the RPA stability matrix becomes nonpositive. Results: By comparing the RPA calculations of atomic nuclei with those performed for SNM we establish a correspondence between the critical densities in the infinite system and the critical coupling constants for which the RPA calculations do not converge. Conclusions: We find a quantitative stability criterion to detect finite-size instabilities related to the spin s .Δ s term of a functional. This criterion could be easily implemented in the standard fitting protocols to fix the coupling constants of the Skyrme functional.
Infrared spectroscopic investigation of nuclear spin conversion in solid CH{sub 4}
Energy Technology Data Exchange (ETDEWEB)
Sugimoto, Takeru; Yamakawa, Koichiro, E-mail: koichiro.yamakawa@gakushuin.ac.jp; Arakawa, Ichiro [Department of Physics, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588 (Japan)
2015-12-14
Infrared spectra of solid CH{sub 4} were studied in the ν{sub 3} and ν{sub 4} vibrational regions. The phase I crystal around 30 K showed broad absorption bands, whereas the phase II crystal at 6.9–10.3 K exhibited splitting of these bands after annealing above 20 K. The split peaks were assigned to the librating and almost freely rotating molecules in phase II on the basis of the peak spacings and time evolution of the peak intensities. From the quantitative analysis of the temporal changes of the R(0) and R(1) peak intensities, the relaxation rates of the numbers of molecules with J = 0 (I = 2) and J = 1 (I = 1) were determined in the temperature range of 6.9–10.3 K. We fitted the function resulting from a combination of direct and indirect relaxation processes mediated by phonons to the temperature dependence of these rates and obtained the activation energies of the indirect process: C ≃ 36 K. Since this value is higher than the energies of perturbed J = 2 states relative to the J = 1 state, we argue that the nuclear spin conversion through the J = 3 state also takes place.
Epand, Richard M.; Bain, Alex D; Sayer, Brian G; Bach, Diana; Wachtel, Ellen
2002-01-01
The behavior of cholesterol is different in mixtures with phosphatidylcholine as compared with phosphatidylserine. In (13)C cross polarization/magic angle spinning nuclear magnetic resonance spectra, resonance peaks of the vinylic carbons of cholesterol are a doublet in samples containing 0.3 or 0.5 mol fraction cholesterol with 1-palmitoyl-2-oleoyl phosphatidylserine (POPS) or in cholesterol monohydrate crystals, but a singlet with mixtures of cholesterol and 1-palmitoyl-2-oleoyl phosphatidy...
The Decoherence of the Electron Spin and Meta-Stability of 13C Nuclear Spins in Diamond
Directory of Open Access Journals (Sweden)
Peter Crompton
2011-05-01
Full Text Available Following the recent successful experimental manipulation of entangled 13C atoms on the surface of Diamond, we calculate the decoherence of the electron spin in Nitrogen Vacancy NV centers of Diamond via a nonperturbative treatment of the time-dependent Greens function of a Central-Spin model in order to identify the Replica Symmetry Breaking mechanism associated with intersystem mixing between the ms = 0 sublevel of the 3A2 and 1A1 states of the NV− centers, which we identify as mediated via the meta-stability of 13C nuclei bath processes in our calculations. Rather than the standard exciton-based calculation scheme used for quantum dots, we argue that a new scheme is needed to formally treat the Replica Symmetry Breaking of the 3A2 → 3E excitations of the NV− centers, which we define by extending the existing Generalized Master Equation formalism via the use of fractional time derivatives. Our calculations allow us to accurately quantify the dangerously irrelevant scaling associated with the Replica Symmetry Breaking and provide an explanation for the experimentally observed room temperature stability of Diamond for Quantum Computing applications.
Nuclear Spin-Lattice Relaxation Times from Continuous Wave NMR Spectroscopy.
Wooten, Jan B.; And Others
1979-01-01
The experiment described, suitable for undergraduate physical chemistry laboratories, illustrates the general principles of relaxation and introduces the nmr concepts of saturation and spin-inversion. (BB)
McCarney, Evan R; Armstrong, Brandon D; Kausik, Ravinath; Han, Songi
2008-09-16
We present a unique analysis tool for the selective detection of local water inside soft molecular assemblies (hydrophobic cores, vesicular bilayers, and micellar structures) suspended in bulk water. Through the use of dynamic nuclear polarization (DNP), the (1)H NMR signal of water is amplified, as it interacts with stable radicals that possess approximately 658 times higher spin polarization. We utilized stable nitroxide radicals covalently attached along the hydrophobic tail of stearic acid molecules that incorporate themselves into surfactant-based micelle or vesicle structures. Here, we present a study of local water content and fluid viscosity inside oleate micelles and vesicles and Triton X-100 micelles to serve as model systems for soft molecular assemblies. This approach is unique because the amplification of the NMR signal is performed in bulk solution and under ambient conditions with site-specific spin labels that only detect the water that is directly interacting with the localized spin labels. Continuous wave (cw) electron spin resonance (ESR) analysis provides rotational dynamics of the spin-labeled molecular chain segments and local polarity parameters that can be related to hydration properties, whereas we show that DNP-enhanced (1)H NMR analysis of fluid samples directly provides translational water dynamics and permeability of the local environment probed by the spin label. Our technique therefore has the potential to become a powerful analysis tool, complementary to cw ESR, to study hydration characteristics of surfactant assemblies, lipid bilayers, or protein aggregates, where water dynamics is a key parameter of their structure and function. In this study, we find that there is significant penetration of water inside the oleate micelles with a higher average local water viscosity (approximately 1.8 cP) than in bulk water, and Triton X-100 micelles and oleate vesicle bilayers mostly exclude water while allowing for considerable surfactant chain
Nuclear spin of odd-odd α emitters based on the behavior of α -particle preformation probability
Ismail, M.; Adel, A.; Botros, M. M.
2016-05-01
The preformation probabilities of an α cluster inside radioactive parent nuclei for both odd-even and odd-odd nuclei are investigated. The calculations cover the isotopic chains from Ir to Ac in the mass regions 166 ≤A ≤215 and 77 ≤Z ≤89 . The calculations are employed in the framework of the density-dependent cluster model. A realistic density-dependent nucleon-nucleon (N N ) interaction with a finite-range exchange part is used to calculate the microscopic α -nucleus potential in the well-established double-folding model. The main effect of antisymmetrization under exchange of nucleons between the α and daughter nuclei has been included in the folding model through the finite-range exchange part of the N N interaction. The calculated potential is then implemented to find both the assault frequency and the penetration probability of the α particle by means of the Wentzel-Kramers-Brillouin approximation in combination with the Bohr-Sommerfeld quantization condition. The correlation of the α -particle preformation probability and the neutron and proton level sequences of the parent nucleus as obtained in our previous work is extended to odd-even and odd-odd nuclei to determine the nuclear spin and parities. Two spin coupling rules are used, namely, strong and weak rules to determine the nuclear spin for odd-odd isotopes. This work can be a useful reference for theoretical calculation of undetermined nuclear spin of odd-odd nuclei in the future.
Theory of long-lived nuclear spin states in methyl groups and quantum-rotor induced polarisation
Energy Technology Data Exchange (ETDEWEB)
Dumez, Jean-Nicolas [School of Chemistry, University of Southampton, Southampton SO17 1BJ (United Kingdom); Institut de Chimie des Substances Naturelles, CNRS UPR2301, Avenue de la Terrasse, 91190 Gif-sur-Yvette (France); Håkansson, Pär; Mamone, Salvatore; Meier, Benno; Stevanato, Gabriele; Hill-Cousins, Joseph T.; Roy, Soumya Singha; Brown, Richard C. D.; Pileio, Giuseppe; Levitt, Malcolm H., E-mail: mhl@soton.ac.uk [School of Chemistry, University of Southampton, Southampton SO17 1BJ (United Kingdom)
2015-01-28
Long-lived nuclear spin states have a relaxation time much longer than the longitudinal relaxation time T{sub 1}. Long-lived states extend significantly the time scales that may be probed with magnetic resonance, with possible applications to transport and binding studies, and to hyperpolarised imaging. Rapidly rotating methyl groups in solution may support a long-lived state, consisting of a population imbalance between states of different spin exchange symmetries. Here, we expand the formalism for describing the behaviour of long-lived nuclear spin states in methyl groups, with special attention to the hyperpolarisation effects observed in {sup 13}CH{sub 3} groups upon rapidly converting a material with low-barrier methyl rotation from the cryogenic solid state to a room-temperature solution [M. Icker and S. Berger, J. Magn. Reson. 219, 1 (2012)]. We analyse the relaxation properties of methyl long-lived states using semi-classical relaxation theory. Numerical simulations are supplemented with a spherical-tensor analysis, which captures the essential properties of methyl long-lived states.
Nuclear magnetic relaxation by the dipolar EMOR mechanism: Three-spin systems
Chang, Zhiwei; Halle, Bertil
2016-07-01
In aqueous systems with immobilized macromolecules, including biological tissue, the longitudinal spin relaxation of water protons is primarily induced by exchange-mediated orientational randomization (EMOR) of intra- and intermolecular magnetic dipole-dipole couplings. Starting from the stochastic Liouville equation, we have developed a non-perturbative theory that can describe relaxation by the dipolar EMOR mechanism over the full range of exchange rates, dipole couplings, and Larmor frequencies. Here, we implement the general dipolar EMOR theory for a macromolecule-bound three-spin system, where one, two, or all three spins exchange with the bulk solution phase. In contrast to the previously studied two-spin system with a single dipole coupling, there are now three dipole couplings, so relaxation is affected by distinct correlations as well as by self-correlations. Moreover, relaxation can now couple the magnetizations with three-spin modes and, in the presence of a static dipole coupling, with two-spin modes. As a result of this complexity, three secondary dispersion steps with different physical origins can appear in the longitudinal relaxation dispersion profile, in addition to the primary dispersion step at the Larmor frequency matching the exchange rate. Furthermore, and in contrast to the two-spin system, longitudinal relaxation can be significantly affected by chemical shifts and by the odd-valued ("imaginary") part of the spectral density function. We anticipate that the detailed studies of two-spin and three-spin systems that have now been completed will provide the foundation for developing an approximate multi-spin dipolar EMOR theory sufficiently accurate and computationally efficient to allow quantitative molecular-level interpretation of frequency-dependent water-proton longitudinal relaxation data from biophysical model systems and soft biological tissue.
Nuclear magnetic relaxation by the dipolar EMOR mechanism: Three-spin systems.
Chang, Zhiwei; Halle, Bertil
2016-07-21
In aqueous systems with immobilized macromolecules, including biological tissue, the longitudinal spin relaxation of water protons is primarily induced by exchange-mediated orientational randomization (EMOR) of intra- and intermolecular magnetic dipole-dipole couplings. Starting from the stochastic Liouville equation, we have developed a non-perturbative theory that can describe relaxation by the dipolar EMOR mechanism over the full range of exchange rates, dipole couplings, and Larmor frequencies. Here, we implement the general dipolar EMOR theory for a macromolecule-bound three-spin system, where one, two, or all three spins exchange with the bulk solution phase. In contrast to the previously studied two-spin system with a single dipole coupling, there are now three dipole couplings, so relaxation is affected by distinct correlations as well as by self-correlations. Moreover, relaxation can now couple the magnetizations with three-spin modes and, in the presence of a static dipole coupling, with two-spin modes. As a result of this complexity, three secondary dispersion steps with different physical origins can appear in the longitudinal relaxation dispersion profile, in addition to the primary dispersion step at the Larmor frequency matching the exchange rate. Furthermore, and in contrast to the two-spin system, longitudinal relaxation can be significantly affected by chemical shifts and by the odd-valued ("imaginary") part of the spectral density function. We anticipate that the detailed studies of two-spin and three-spin systems that have now been completed will provide the foundation for developing an approximate multi-spin dipolar EMOR theory sufficiently accurate and computationally efficient to allow quantitative molecular-level interpretation of frequency-dependent water-proton longitudinal relaxation data from biophysical model systems and soft biological tissue. PMID:27448879
Implementation of Liouville space search algorithm on strongly dipolar coupled nuclear spins
Gopinath, T
2009-01-01
Liouville space search algorithm [Bruschweiler, Phys. Rev. Lett. {\\bf 85}, 4815(2000).] utilizes mixed initial states of the ensemble, and has been successfully implemented earlier in weakly coupled spins, in which a spin can be identified as a qubit. It has recently been demonstrated that n-strongly coupled spins can be collectively treated as an n-qubit system. Application of algorithms in such systems, requires new approaches using transition selective pulses rather than qubit selective pulses. This work develops a modified version of Liouville space search algorithm, which is applicable for strongly as well as weakly coupled spins. All the steps of the algorithm, can be implemented by using transition selective pulses. Experimental implementation is carried out on a strongly dipolar coupled four qubit system.
Analytic approach to nuclear rotational states: The role of spin (I) A minimal model
Bentz, W; Richter, A; Wambach, J
2013-01-01
We use a simple field theory model to investigate the role of the nucleon spin for the magnetic sum rules associated with the low-lying collective scissors mode in deformed nuclei. Various constraints from rotational symmetry are elucidated and discussed. We put special emphasis on the coupling of the spin part of the M1 operator to the low lying collective modes, and investigate how this coupling changes the sum rules.
Energy Technology Data Exchange (ETDEWEB)
Saiz-Jimenez, C.; Hawkins, B.L.; Maciel, G.E.
1986-01-01
Cross polarization, magic-angle spinning /sup 13/C nuclear magnetic resonance spectroscopy was used to characterize humic fractions isolated from different soils. The humic acid fractions are more aromatic than the humin fractions, probably due to the higher polysaccharide content of humins. However, fulvic acid fractions are more aromatic than the corresponding humic acid and humin fractions. These results can be interpreted in terms of the isolation procedure, because the high affinity of Polyclar AT for phenols results in higher aromaticities as compared with other isolation methods (e.g. charcoal).
Efficient calculation of nuclear spin-rotation constants from auxiliary density functional theory
Energy Technology Data Exchange (ETDEWEB)
Zuniga-Gutierrez, Bernardo, E-mail: bzuniga.51@gmail.com [Departamento de Ciencias Computacionales, Universidad de Guadalajara, Blvd. Marcelino García Barragán 1421, C.P. 44430 Guadalajara, Jalisco (Mexico); Camacho-Gonzalez, Monica [Universidad Tecnológica de Tecámac, División A2, Procesos Industriales, Carretera Federal México Pachuca Km 37.5, Col. Sierra Hermosa, C.P. 55740 Tecámac, Estado de México (Mexico); Bendana-Castillo, Alfonso [Universidad Tecnológica de Tecámac, División A3, Tecnologías de la Información y Comunicaciones, Carretera Federal México Pachuca Km 37.5, Col. Sierra Hermosa, C.P. 55740 Tecámac, Estado de México (Mexico); Simon-Bastida, Patricia [Universidad Tecnlógica de Tulancingo, División Electromecánica, Camino a Ahuehuetitla No. 301, Col. Las Presas, C.P. 43642 Tulancingo, Hidalgo (Mexico); Calaminici, Patrizia; Köster, Andreas M. [Departamento de Química, CINVESTAV, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740, México D.F. 07000 (Mexico)
2015-09-14
The computation of the spin-rotation tensor within the framework of auxiliary density functional theory (ADFT) in combination with the gauge including atomic orbital (GIAO) scheme, to treat the gauge origin problem, is presented. For the spin-rotation tensor, the calculation of the magnetic shielding tensor represents the most demanding computational task. Employing the ADFT-GIAO methodology, the central processing unit time for the magnetic shielding tensor calculation can be dramatically reduced. In this work, the quality of spin-rotation constants obtained with the ADFT-GIAO methodology is compared with available experimental data as well as with other theoretical results at the Hartree-Fock and coupled-cluster level of theory. It is found that the agreement between the ADFT-GIAO results and the experiment is good and very similar to the ones obtained by the coupled-cluster single-doubles-perturbative triples-GIAO methodology. With the improved computational performance achieved, the computation of the spin-rotation tensors of large systems or along Born-Oppenheimer molecular dynamics trajectories becomes feasible in reasonable times. Three models of carbon fullerenes containing hundreds of atoms and thousands of basis functions are used for benchmarking the performance. Furthermore, a theoretical study of temperature effects on the structure and spin-rotation tensor of the H{sup 12}C–{sup 12}CH–DF complex is presented. Here, the temperature dependency of the spin-rotation tensor of the fluorine nucleus can be used to identify experimentally the so far unknown bent isomer of this complex. To the best of our knowledge this is the first time that temperature effects on the spin-rotation tensor are investigated.
Hayashida, H.; Oku, T.; Kira, H.; Sakai, K.; Hiroi, K.; Ino, T.; Shinohara, T.; Imagawa, T.; Ohkawara, M.; Ohoyama, K.; Kakurai, K.; Takeda, M.; Yamazaki, D.; Oikawa, K.; Harada, M.; Miyata, N.; Akutsu, K.; Mizusawa, M.; Parker, J. D.; Matsumoto, Y.; Zhang, S.; Suzuki, J.; Soyama, K.; Aizawa, K.; Arai, M.
2016-04-01
We have been developing a 3He neutron spin filter (NSF) using the spin exchange optical pumping (SEOP) technique. The 3He NSF provides a high-energy polarized neutron beam with large beam size. Moreover the 3He NSF can work as a π-flipper for a polarized neutron beam by flipping the 3He nuclear spin using a nuclear magnetic resonance (NMR) technique. For NMR with the in-situ SEOP technique, the polarization of the laser must be reversed simultaneously because a non-reversed laser reduces the polarization of the spin-flipped 3He. To change the polarity of the laser, a half-wavelength plate was installed. The rotation angle of the half-wavelength plate was optimized, and a polarization of 97% was obtained for the circularly polarized laser. The 3He polarization reached 70% and was stable over one week. A demonstration of the 3He nuclear spin flip system was performed at the polarized neutron reflectometer SHARAKU (BL17) and NOBORU (BL10) at J-PARC. Off-specular measurement from a magnetic Fe/Cr thin film and magnetic imaging of a magnetic steel sheet were performed at BL17 and BL10, respectively.
Thurber, Kent; Tycko, Robert
2016-03-01
We describe novel instrumentation for low-temperature solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS), focusing on aspects of this instrumentation that have not been described in detail in previous publications. We characterize the performance of an extended interaction oscillator (EIO) microwave source, operating near 264 GHz with 1.5 W output power, which we use in conjunction with a quasi-optical microwave polarizing system and a MAS NMR probe that employs liquid helium for sample cooling and nitrogen gas for sample spinning. Enhancement factors for cross-polarized (13)C NMR signals in the 100-200 range are demonstrated with DNP at 25K. The dependences of signal amplitudes on sample temperature, as well as microwave power, polarization, and frequency, are presented. We show that sample temperatures below 30K can be achieved with helium consumption rates below 1.3 l/h. To illustrate potential applications of this instrumentation in structural studies of biochemical systems, we compare results from low-temperature DNP experiments on a calmodulin-binding peptide in its free and bound states.
Thurber, Kent; Tycko, Robert
2016-03-01
We describe novel instrumentation for low-temperature solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS), focusing on aspects of this instrumentation that have not been described in detail in previous publications. We characterize the performance of an extended interaction oscillator (EIO) microwave source, operating near 264 GHz with 1.5 W output power, which we use in conjunction with a quasi-optical microwave polarizing system and a MAS NMR probe that employs liquid helium for sample cooling and nitrogen gas for sample spinning. Enhancement factors for cross-polarized 13C NMR signals in the 100-200 range are demonstrated with DNP at 25 K. The dependences of signal amplitudes on sample temperature, as well as microwave power, polarization, and frequency, are presented. We show that sample temperatures below 30 K can be achieved with helium consumption rates below 1.3 l/h. To illustrate potential applications of this instrumentation in structural studies of biochemical systems, we compare results from low-temperature DNP experiments on a calmodulin-binding peptide in its free and bound states.
Marumoto, K.; Kato, M.; Kondo, H.; Kuroda, S.; Greenham, N. C.; Friend, R. H.; Shimoi, Y.; Abe, S.
2009-06-01
Electron spin resonance (ESR) and electron-nuclear double resonance (ENDOR) of photogenerated polarons in poly(9,9-dioctylfluorene) (PFO) and its composite with fullerene (C60) using variable photoexcitation energy up to 4.1 eV are reported. For PFO, a light-induced ESR (LESR) signal (g=2.003) is observed below 60 K, and its transient response and excitation spectrum indicate that the observed spins are photogenerated polarons on PFO. For the PFO-C60 composite, two LESR signals of photogenerated positive polarons on PFO (g1=2.003) and radical anions on C60 (g2=1.999) , respectively, are observed below 120 K, which are caused by photoinduced electron transfer from PFO to C60 . A remarkable enhancement of the LESR signals in the excitation spectrum at ˜2.8eV is observed compared with the case of pure PFO. The bimolecular-recombination kinetics of photogenerated charge carriers in the composite are confirmed by the dependence of the LESR on excitation-light intensity and by the decay dynamics. Light-induced ENDOR (LENDOR) signals are clearly observed for excitation around 2.8 eV owing to the highly efficient photoinduced electron transfer in the composite. Broad LENDOR shifts directly reflect the spin-density distribution of the polarons in PFO. We have determined its maximum shift using LENDOR-induced ESR, and have evaluated the maximum spin density on the carbon site coupled to the proton as 0.032. This value is consistent with the theoretical result obtained by Pariser-Parr-Pople (PPP) model, where the spatial extent of the polarons is calculated as ˜3 monomer units of PFO. The calculated LESR spectra of PFO based on the PPP model are consistent with the experimental spectra, which confirm the above spatial extension of the polaron in PFO.
Nuclear spins of the isomers /sup 191m-185m/Hg determined by on-line quantum-beat spectroscopy
Kremmling, H; Fischer, H G; Kluge, H J; Kühl, T; Schüssler, H A
1979-01-01
The nuclear spins of the very neutron-deficient /sup 191m-185m/Hg isomers were measured on line at the mass separator ISOLIDE at CERN using pulsed-laser excitation and observation of the time-resolved quantum beats from selected hyperfine-structure states. The spins of these isomers are with I=13/2 equal to those of the long-lived isomers /sup 199m-193m/Hg already known. The persistence of this spin value for eight isomers is explained by the model of rotation-aligned coupling. (12 refs).
International Nuclear Information System (INIS)
The experimental and theoretical studies of Giant Resonances, or more generally of the nuclear collective vibrations, are a well-established domain in which sophisticated techniques have been introduced and firm conclusions reached after an effort of several decades. From it, information on the nuclear equation of state can be extracted, albeit not far from usual nuclear densities. In this contribution, which complements other contributions appearing in this topical issue, we survey some of the constraints that have been extracted recently concerning the parameters of the nuclear symmetry energy. Isovector modes, in which neutrons and protons are in opposite phase, are a natural source of information and we illustrate the values of symmetry energy around saturation deduced from isovector dipole and isovector quadrupole states. The isotopic dependence of the isoscalar monopole energy has also been suggested to provide a connection to the symmetry energy: relevant theoretical arguments and experimental results are thoroughly discussed. Finally, we consider the case of the charge-exchange spin-dipole excitations in which the sum rule associated with the total strength gives in principle access to the neutron skin and thus, indirectly, to the symmetry energy. (orig.)
Devices and process for high-pressure magic angle spinning nuclear magnetic resonance
Hoyt, David W; Sears, Jr., Jesse A; Turcu, Romulus V.F.; Rosso, Kevin M; Hu, Jian Zhi
2014-04-08
A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.
Dynamic nuclear polarization at 40 kHz magic angle spinning.
Chaudhari, Sachin R; Berruyer, Pierrick; Gajan, David; Reiter, Christian; Engelke, Frank; Silverio, Daniel L; Copéret, Christophe; Lelli, Moreno; Lesage, Anne; Emsley, Lyndon
2016-04-21
DNP-enhanced solid-state NMR spectroscopy under magic angle spinning (MAS) is rapidly developing into a powerful analytical tool to investigate the structure of a wide range of solid materials, because it provides unsurpassed sensitivity gains. Most developments and applications of DNP MAS NMR were so far reported at moderate spinning frequencies (up to 14 kHz using 3.2 mm rotors). Here, using a 1.3 mm MAS DNP probe operating at 18.8 T and ∼100 K, we show that signal amplification factors can be increased by up to a factor two when using smaller volume rotors as compared to 3.2 mm rotors, and report enhancements of around 60 over a range of sample spinning rates from 10 to 40 kHz. Spinning at 40 kHz is also shown to increase (29)Si coherence lifetimes by a factor three as compared to 10 kHz, substantially increasing sensitivity in CPMG type experiments. The contribution of quenching effects to the overall sensitivity gain at very fast MAS is evaluated, and applications are reported on a functionalised mesostructured organic-inorganic material.
Lupulescu, Adonis; Frydman, Lucio
2011-10-01
Recent years have witnessed efforts geared at increasing the sensitivity of NMR experiments, by relying on the suitable tailoring and exploitation of relaxation phenomena. These efforts have included the use of paramagnetic agents, enhanced (1)H-(1)H incoherent and coherent transfers processes in 2D liquid state spectroscopy, and homonuclear (13)C-(13)C spin diffusion effects in labeled solids. The present study examines some of the opportunities that could open when exploiting spontaneous (1)H-(1)H spin-diffusion processes, to enhance relaxation and to improve the sensitivity of dilute nuclei in solid state NMR measurements. It is shown that polarization transfer experiments executed under sufficiently fast magic-angle-spinning conditions, enable a selective polarization of the dilute low-γ spins by their immediate neighboring protons. Repolarization of the latter can then occur during the time involved in monitoring the signal emitted by the low-γ nuclei. The basic features involved in the resulting approach, and its potential to improve the effective sensitivity of solid state NMR measurements on dilute nuclei, are analyzed. Experimental tests witness the advantages that could reside from utilizing this kind of approach over conventional cross-polarization processes. These measurements also highlight a number of limitations that will have to be overcome for transforming selective polarization transfers of this kind into analytical methods of choice.
Dynamic nuclear polarization at 40 kHz magic angle spinning.
Chaudhari, Sachin R; Berruyer, Pierrick; Gajan, David; Reiter, Christian; Engelke, Frank; Silverio, Daniel L; Copéret, Christophe; Lelli, Moreno; Lesage, Anne; Emsley, Lyndon
2016-04-21
DNP-enhanced solid-state NMR spectroscopy under magic angle spinning (MAS) is rapidly developing into a powerful analytical tool to investigate the structure of a wide range of solid materials, because it provides unsurpassed sensitivity gains. Most developments and applications of DNP MAS NMR were so far reported at moderate spinning frequencies (up to 14 kHz using 3.2 mm rotors). Here, using a 1.3 mm MAS DNP probe operating at 18.8 T and ∼100 K, we show that signal amplification factors can be increased by up to a factor two when using smaller volume rotors as compared to 3.2 mm rotors, and report enhancements of around 60 over a range of sample spinning rates from 10 to 40 kHz. Spinning at 40 kHz is also shown to increase (29)Si coherence lifetimes by a factor three as compared to 10 kHz, substantially increasing sensitivity in CPMG type experiments. The contribution of quenching effects to the overall sensitivity gain at very fast MAS is evaluated, and applications are reported on a functionalised mesostructured organic-inorganic material. PMID:27035630
Anisotropic collective motion contributes to nuclear spin relaxation in crystalline proteins.
Lewandowski, Józef R; Sein, Julien; Blackledge, Martin; Emsley, Lyndon
2010-02-01
A model for calculating the influence of anisotropic collective motions on NMR relaxation rates in crystalline proteins is presented. We show that small-amplitude (<10 degrees ) fluctuations may lead to substantial contributions to the (15)N spin-lattice relaxation rates and propose that the effect of domain motions should be included in solid-state NMR analyses of protein dynamics. PMID:19916496
On shape of NMR absorption spectra and cross-relaxation in hetero nuclear spin system
Zobov, V E; Rodionova, O E
2001-01-01
The dynamic theory of the heteronuclear spin systems in solid bodies at high temperatures is developed. The system of the nonlinear integral equations is obtained for the time spin correlation functions in the approximation of the self-consistent fluctuating local field. The corrections, originating due to the fluctuating local fields correlations, existing in the real lattices, are accounted for thereby. The theory is applied to describing available experimental data for the LiF crystal (with two nuclei kinds). The free precession signals for the Li and F nuclei, as well as, the harmonic cross-relaxation spectra, the sup 6 Li isotope cross-polarization and the sup 8 Li isotope depolarization are calculated by the magnetic field orientations along the basic crystallographic axes. Good agreement between theory and experiment is achieved
Mazurek, K.; Dudek, J.; Maj, A.; Rouvel, D.
2015-03-01
We present a theoretical analysis of the competition between the so-called nuclear Jacobi and Poincaré shape transitions as a function of spin at high temperatures. The latter condition implies the method of choice, a realistic version of the nuclear liquid drop model, here the Lublin-Strasbourg drop model. We address specifically the fact that the Jacobi and Poincaré shape transitions are accompanied by the flattening of the total nuclear energy landscape as a function of the relevant deformation parameters, which enforces large-amplitude oscillation modes that need to be taken into account. For that purpose we introduce an approximate form of the collective Schrödinger equation whose solutions are used to calculate the most probable deformations associated with the nuclear Jacobi and Poincaré transitions. We discuss selected aspects of the new description focusing on the critical-spin values for both types of these transitions.
1974-01-01
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.
Spin noise in mixed Spin Systems
Bauch, Erik; Junghyun, Paul; Singh, Swati; Devakul, Trithep; Feguin, Adrian; Hart, Connor; Walsworth, Ronald
2016-05-01
The spin noise due to interaction of multiple spin species in mixed spin systems provides a fundamental limit to ultra-sensitive ensemble sensing and quantum information applications. In our work, we investigate the interaction of dense nuclear 13C spins with electronic nitrogen spins using Nitrogen-Vacancy centers in diamond. Our work shows experimentally and theoretically, that under certain conditions, spin noise is greatly suppressed and the coherence time of NV centers improved by order of magnitudes, providing a pathway to engineering high density ensemble samples with long coherence times at room temperature.
Guskov, K I
1999-01-01
The symmetrized contribution of $E$-type spin-rotation interaction to conversion between spin modifications of $E$- and $A_1$-types in molecules with ${\\rm C}_{3{\\rm v}}$-symmetry is considered. Using the high-$J$ descending of collisional broadening for accidental rotational resonances between these spin modifications, it was possible to co-ordinate the theoretical description of the conversion with (updated) experimental data for two carbon-substituted isotopes of fluoromethane. As a result, both $E$% -type spin-rotation constants are obtained. They are roughly one and a half times more than the corresponding constants for (deutero)methane.
Inoue, T.; Tsuchiya, M.; Furukawa, T.; Hayashi, H.; Nanao, T.; Yoshimi, A.; Uchida, M.; Matsuo, Y.; Asahi, K.
2011-01-01
Frequency characteristics of a 129Xe nuclear spin maser was studied, which is under development at Tokyo Institute of Technology for the search for a permanent electric dipole moment in diamagnetic 129Xe atom. Drifts in the solenoid current and cell temperature were found to be the most influential factors on the maser frequency. From correlation coefficient analysis, there seem to exist other origins of frequency fluctuation, such as phase drifts in the maser oscillation. In order to improve the stability of the maser frequency, the intensity of the pumping laser required to fully polarize 129Xe nuclei was evaluated. Construction of a polarization assessment system for 129Xe gas cells and development of a new scheme of current stabilization are also remarked.
Energy Technology Data Exchange (ETDEWEB)
Fujita, T., E-mail: tomomi.fujita@riken.jp [Osaka University, Department of Physics (Japan); Furukawa, T. [Tokyo Metropolitan University, Department of Physics (Japan); Imamura, K.; Yang, X. F. [RIKEN Nishina Center (Japan); Hatakeyama, A. [Tokyo University of Agriculture and Technology, Department of Applied Physics (Japan); Kobayashi, T. [RIKEN Center for Advanced Photonics (Japan); Ueno, H. [RIKEN Nishina Center (Japan); Asahi, K. [Tokyo Institute of Technology, Department of Physics (Japan); Shimoda, T. [Osaka University, Department of Physics (Japan); Matsuo, Y. [Hosei University, Department of Advanced Sciences (Japan); Collaboration: OROCHI Collaboration
2015-11-15
A new laser spectroscopic method named “OROCHI (Optical RI-atom Observation in Condensed Helium as Ion catcher)” has been developed for deriving the nuclear spins and electromagnetic moments of low-yield exotic nuclei. In this method, we observe atomic Zeeman and hyperfine structures using laser-radio-frequency/microwave double-resonance spectroscopy. In our previous works, double-resonance spectroscopy was performed successfully with laser-sputtered stable atoms including non-alkali Au atoms as well as alkali Rb and Cs atoms. Following these works, measurements with {sup 84−87}Rb energetic ion beams were carried out in the RIKEN projectile fragment separator (RIPS). In this paper, we report the present status of OROCHI and discuss its feasibility, especially for low-yield nuclei such as unstable Au isotopes.
Energy Technology Data Exchange (ETDEWEB)
Oehms, Ole Benjamin
2009-07-10
In the framework of this thesis a combined method of ultrasound and nuclear-spin tomography is presented. Via ultrasound pulses by the sound-radiation force in liquids and tissue phantoms motions are generated, which depend on ther viscoelastic properties. This motions are made visible by a motion-sensitive tomograph sequence in the phase image of the tomograph in form of a phase change. The first measurements on simple phantoms and liquids are presented. [German] Im Rahmen dieser Arbeit wird eine kombinierte Methode aus Ultraschall und Kernspintomographie vorgestellt. Ueber Ultraschallpulse werden durch die Schallstrahlungskraft in Fluessigkeiten und Gewebephantomen Bewegungen erzeugt, die von den viskoelastischen Eigenschaften abhaengen. Diese Bewegungen werden mit einer bewegungssensitiven Tomographensequenz im Phasenbild des Tomographen in Form einer Phasenaenderung sichtbar gemacht. Die ersten Messungen an einfachen Phantomen und Fluessigkeiten werden praesentiert. (orig.)
Saito, A; Akagi, Y; Hashizume, N; Ohta, K
2000-01-01
We found that the actual computational time-cost of the QFT is O(n 2^n) for large n in a quantum computer using nuclear spins. The computational cost of a quantum algorithm has usually been estimated as the sum of the universal gates required in such ideal mathematical models as the Quantum Turing Machine(QTM) and the quantum circuit. This cost is proportional to an actual time-cost in the physical implementation where all quantum operations can be achieved in the same time. However, if the implementation takes a different time for each quantum gate, there is a possibility that the actual time-cost will have a different behavior from the ideal cost. So we estimated the actual time-cost of the QFT in these implementations by considering the gating time. The actual time-cost is drastically different from O(n^2) estimated by complexity analysis.
Nuclear structure at high spin using multidetector gamma array and ancillary detectors
Indian Academy of Sciences (India)
S Muralithar
2014-04-01
A multidetector gamma array (GDA), for studying nuclear structure was built with ancillary devices namely gamma multiplicity filter and charged particle detector array. This facility was designed for in-beam gamma spectroscopy measurements in fusion evaporation reactions at Inter-University Accelerator Centre, New Delhi. Description of the facility and in-beam performance with two experimental studies done are presented. This array was used in a number of nuclear spectroscopic and reaction investigations.
Chang, Zhiwei; Halle, Bertil
2013-10-01
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
Kalev, LA; Niesen, L
2003-01-01
A thin magnetite film grown by molecular-beam epitaxy on MgO(100) was studied by nuclear resonant scattering (NRS) at grazing incidence geometry. We show that the NRS data yield more information about the shape of the directional spin distribution than Mossbauer spectroscopy, in which only the avera
DEFF Research Database (Denmark)
Jankowska, Marzena; Kupka, Teobald; Stobiński, Leszek;
2016-01-01
corrections were calculated with the scalar and spin-orbit zeroth-order regular approximation Hamiltonian in combination with the large Slater-type basis set QZ4P as well as with the 4-component Dirac-Coulomb Hamiltonian using Dyall’s acv4z basis sets. The relativistic corrections to the nuclear magnetic...
Hu, Jian Zhi; Sears, Jr., Jesse A.; Hoyt, David W.; Mehta, Hardeep S.; Peden, Charles H. F.
2015-11-24
A continuous-flow (CF) magic angle sample spinning (CF-MAS) NMR rotor and probe are described for investigating reaction dynamics, stable intermediates/transition states, and mechanisms of catalytic reactions in situ. The rotor includes a sample chamber of a flow-through design with a large sample volume that delivers a flow of reactants through a catalyst bed contained within the sample cell allowing in-situ investigations of reactants and products. Flow through the sample chamber improves diffusion of reactants and products through the catalyst. The large volume of the sample chamber enhances sensitivity permitting in situ .sup.13C CF-MAS studies at natural abundance.
Mazurek, K; Maj, A; Rouvel, D
2013-01-01
We present a theoretical analysis of the competition between so-called nuclear Jacobi and Poincar\\'e shape transitions in function of spin - at high temperatures. The latter condition implies the method of choice - a realistic version of the nuclear Liquid Drop Model (LDM), here: the Lublin-Strasbourg Drop (LSD) model. We address specifically the fact that the Jacobi and Poincar\\'e shape transitions are accompanied by the flattening of total nuclear energy landscape as function of the relevant deformation parameters what enforces large amplitude oscillation modes that need to be taken into account. For that purpose we introduce an approximate form of the collective Schr\\"odinger equation whose solutions are used to calculate the most probable deformations associated with both types of transitions and discuss the physical consequences in terms of the associated critical-spin values and transitions themselves.
Impact of pairing anti-viscosity on the orientation of the nuclear spin
Zhao, P W; Meng, J
2015-01-01
For the first time, the tilted axis cranking covariant density functional theory with pairing correlations has been formulated and implemented in a fully self-consistent and microscopic way to investigate the evolution of the spin axis and the pairing effects in rotating triaxial nuclei. The measured energy spectrum and transition probabilities for the Nd-135 yrast band are reproduced well without any ad hoc renormalization factors when pairing effects are taken into account. A transition from collective to chiral rotation has been demonstrated. It is found that pairing correlations introduce additional admixtures in the single-particle orbitals, and, thus, result in "pairing anti- viscosity", which influences the structure of tilted axis rotating nuclei by reducing the magnitude of the proton and neutron angular momenta while merging their direction.
Effect of nuclear spin on chemical reactions and internal molecular rotation
International Nuclear Information System (INIS)
Part I of this dissertation is a study of the magnetic isotope effect, and results are presented for the separation of 13C and 12C isotopes. Two models are included in the theoretical treatment of the effect. In the first model the spin states evolve quantum mechanically, and geminate recombination is calculated by numerically integrating the collision probability times the probability the radical pair is in a singlet state. In the second model the intersystem crossing is treated via first-order rate constants which are average values of the hyperfine couplings. Using these rate constants and hydrodynamic diffusion equations, an analytical solution, which accounts for all collisions, is obtained for the geminate recombination. The two reactions studied are photolysis of benzophenone and toluene and the photolytic decomposition of dibenzylketone (1,3-diphenyl-2-propanone). No magnetic isotope effect was observed in the benzophenone reaction. 13C enrichment was observed for the dibenzylketone reaction, and this enrichment was substantially enhanced at intermediate viscosities and low temperatures. Part II of this dissertation is a presentation of theory and results for the use of Zeeman spin-lattice relaxation as a probe of methyl group rotation in the solid state. Experimental results are presented for the time and angular dependences of rotational polarization, the methyl group magnetic moment, and methyl-methyl steric interactions. The compounds studied are 2,6-dimethylphenol, methyl iodide, 1,4,5,8-tetramethylanthracene, 1,4,5,8-tetramethylnaphthalene, 1,2,4,5-tetramethylbenzene, and 2,3-dimethylmaleicanhydride
Rat, Sylvain; Mikolasek, Mirko; Costá, José Sánchez; Chumakov, Aleksandr I.; Nicolazzi, William; Molnár, Gábor; Salmon, Lionel; Bousseksou, Azzedine
2016-06-01
We report on a combined nuclear inelastic scattering and metal isotope substitution based Raman spectroscopic investigation of lattice dynamics changes associated with the spin transition in the ferrous complex [Fe(H2B(pz)2)2(phen)] (pz = pyrazolyl, phen = 1,10-phenantroline). These techniques allowed us to identify Raman active metal - ligand stretching vibrations in the high spin (vHS = 232 cm-1) and low spin (vLS = 390 cm-1) states as well as to calculate associated changes of the Debye temperature (ΘDHS = 140 K, ΘDLS = 146 K), Debye sound velocity (vHS = 1282 m/s, vLS = 1300 m/s) and Young's modulus (EHS = 4.7 GPa, ELS = 5.2 GPa).
Villanueva, G.; Mumma, M.; Bonev, B.; DiSanti, M.; Paganini, L.; Magee-Sauer, K.; Gibb, E.
2014-07-01
Comets are true remnants of our primordial Solar System, and provide unique clues to its formation and evolution, including the delivery of organics and water to our planet. A key indicator stored in the molecular structure of the nuclear ices is the spin temperature (T_{spin}), derived from spin-isomeric ratios (R_{spin}, e.g., ortho/para). At the time when cometary ices formed, the prevailing temperature defined the relative abundance of the different spin-isomeric species, and herewith R_{spin} and T_{spin} are normally treated as ''remnant thermometers'' probing the formation environments of cometary molecules. Radiative and collisional transitions between the ortho and para states are strongly forbidden and herewith this indicator is preserved over time. Most of our knowledge of this indicator comes from the measurements of the ortho-para ratios in water and NH_2 (a proxy for ammonia), suggesting a common T_{spin} near 30 K. This information is based on a restricted sample of comets, and the measurements are particularly sensitive to the molecular modeling technique and adopted spectral database. Here, we present new methodologies for extracting spin temperatures from ethane (C_2H_6), methane (CH_4), and methanol (CH_3OH), and advanced new models for ortho/para water (H_2O) and ammonia (NH_3). Our H_2O analysis is based on the most complete fluorescence radiative-transfer model to date, which incorporates 1,200 million transitions including those originating from high-energy levels that are activated in comets via a non-resonant cascade. In a similar fashion, we developed non-resonant fluorescence models for NH_3 and HCN, and quantum-band models for the ν_7 band of C_2H_6 and ν_3 band of CH_3OH. All models respect spin-symmetry non-conversion radiative rules, and make use of a realistic solar spectrum for the computation of fluorescence pumps. We applied these new methods to derive spin-isomeric ratios for H_2O, CH_4, C_2H_6, CH_3OH, and NH_3 from three high
Directory of Open Access Journals (Sweden)
Quade, U.
2005-12-01
Full Text Available In the 1980ies, Siempelkamp foundry in Krefeld, Germany, developed a process to melt medium and slightly radioactive metals from decommissioning and maintenance works in nuclear power plants. Since 1989, in the CARLA melting plant which is licensed according to the German radiation protection ordinance (StrlSchV, metals are being molten which, for the largest part, can be reused. Since 1998, in a second plant, the GERTA melting plant, metals with a content of mercury up to 1 weight %, natural radioactivity up to 500 Bq/g and other chemical contaminations are being molten and completely decontaminated, so that these metals can be reused in the steel cycle. The following text is describing the melting process, acceptance criteria for contaminated scrap and recycling paths for the produced ingots and slags.
La fundición Siempelkamp en Krefeld, Alemania, desarrolló, en los años 80, un proceso para fundir metales mediana y levemente radioactivos, procedentes de reparaciones o desmantelamiento de plantas nucleares. En la planta de fundición CARLA, que cumple los requisitos del decreto de protección contra radiaciones de la República Federal de Alemania, se funden metales desde 1989, de los cuales la mayor parte puede ser utilizada nuevamente. Desde 1998, en una segunda planta, fundición GERTA, se funden y descontaminan totalmente, metales de hasta un 1 % de peso de mercurio, con una radioactividad natural de hasta 500 Bq/g y con otros contaminantes químicos. De este modo los metales pueden ser nuevamente utilizados en el ciclo metálico. El texto adjunto describe el método para el fundido, los criterios para aceptar chatarra contaminada y las vías de utilización para los bloques de metal y escorias generadas en el proceso.
Chatterji, T; Jalarvo, N; Kumar, C M N; Xiao, Y; Brückel, Th
2013-07-17
We have investigated low energy nuclear spin excitations in the strongly correlated electron compound HoCrO3. We observe clear inelastic peaks at E = 22.18 ± 0.04 μeV in both energy loss and gain sides. The energy of the inelastic peaks remains constant in the temperature range 1.5-40 K at which they are observed. The intensity of the inelastic peak increases at first with increasing temperature and then decreases at higher temperatures. The temperature dependence of the energy and intensity of the inelastic peaks is very unusual compared to that observed in other Nd, Co, V and also simple Ho compounds. Huge quasielastic scattering appears at higher temperatures presumably due to the fluctuating electronic moments of the Ho ions that get increasingly disordered at higher temperatures. The strong quasielastic scattering may also originate in the first Ho crystal-field excitations at about 1.5 meV.
Spurious finite-size instabilities in nuclear energy density functionals: spin channel
Pastore, A; Davesne, D; Navarro, J
2015-01-01
It has been recently shown, that some Skyrme functionals can lead to non-converging results in the calculation of some properties of atomic nuclei. A previous study has pointed out a possible link between these convergence problems and the appearance of finite-size instabilities in symmetric nuclear matter (SNM) around saturation density. We show that the finite-size instabilities not only affect the ground state properties of atomic nuclei, but they can also influence the calculations of vibrational excited states in finite nuclei. We perform systematic fully-self consistent Random Phase Approximation (RPA) calculations in spherical doubly-magic nuclei. We employ several Skyrme functionals and vary the isoscalar and isovector coupling constants of the time-odd term $\\mathbf{s}\\cdot \\Delta \\mathbf{s}$ . We determine critical values of these coupling constants beyond which the RPA calculations do not converge because RPA the stability matrix becomes non-positive.By comparing the RPA calculations of atomic nucl...
Bacskay, George B.
1995-08-01
A theoretical study of the Fermi contact contribution to the HH and HD spin-spin coupling constant is reported, with special emphasis on its calculation using quantum chemical techniques over a wide range of internuclear distances, that has necessitated an extension of the existing methodology so the effects of near-degeneracy are properly treated. A detailed configuration interaction calculation on H 2 shows that as the molecule is stretched the coupling constant displays a sharp increase before decaying to zero as the molecule dissociates. Such distance dependence is reflected in the calculated vibrational averages of the coupling constant for HD that show a rapid increase with vibrational excitation.
International Nuclear Information System (INIS)
The spin-orbit interaction depends on the spin orientation of the nucleons with respect to their angular momenta as well as on the derivative of the nuclear density. Even though this density dependence is used in all mean field model, it has never been tested yet due to the lack of data. We propose an original method to test this density dependence by comparing a bubble nucleus (34Si) to a normal nucleus (36S). The 34Si exhibits a central density which is depleted by a factor of two which induces a non-zero central density derivative and should change the strength of the spin orbit interaction for the inner orbits such as the p orbits (L=1). By performing (d,p) transfer reactions with 36S and 34Si beams, the p(3/2) and p(1/2) spin orbit splitting can be inferred for these nuclei. Depending on the models, the spin-orbit splitting varies from 7% (VlowK interaction) up to 70% (Relativistic mean field approach). Beams of 36S and 34Si, produced at the LISE spectrometer at 20 A.MeV, were impinged onto a CD2 target. Tracking the beam particles was achieved using 2 xy beam tracking gas detectors. Protons emitted were detected by 4 multi-segmented Si detectors (MUST2) placed at backwards angles. Gammas issued from the excited states decay were detected in the 4 EXOGAM segmented Germanium detectors. Transfer like nuclei were identified with an ionization chamber and a plastic detector. The excitation energy spectra of the 37S and 35Si are determined up to about 7 MeV. Spectroscopic factors and energies of p and f states are derived for the first time in 35Si. The two nuclei show strong similarity for the f spin-orbit partners, whereas the p(3/2) - p(1/2) energy gap is reduced by 55%. (author)
What can the nuclear high-spin properties tell us about the decrease of the pair-correlation energy
International Nuclear Information System (INIS)
Pair-correlation energies at high spins are studied in cranking-HFB calculations under several model assumptions. The results are compared with experimental high-spin data: a) yrastlines of even-even nuclei b) systematics of rotational bands of odd-N nuclei and c) routhians of odd-N nuclei relative to corresponding routhians of neighbouring even-N isotopes. (author)
A study on the improvement of spin-off effectiveness of national nuclear R and D activities
International Nuclear Information System (INIS)
This study consists of two parts. One is to identify factors affecting technological effectiveness of the spin-off process that is defined as the technology transfer process from government sponsored research institutes (GRI's) to the civilian sector. The other is to analyze the environment of the spin-off process and to suggest guidelines for addition, this study also examines spin-off effectiveness with technology transfer types. To validate the conceptual model and hypotheses of the spin-off process, data are collected from 12 cases through in-depth interviews and questionnaires. Spearman correlation analysis is employed in order to test the hypotheses on the spin-off process. (author). 50 refs., 17 tabs., 12 figs
2002-01-01
We aim at establishing an unambiguous spin determination of the ground and isomeric states in the neutron rich Cu-isotopes from A=72 up to A=78 and to measure the magnetic and quadrupole moments between the N=28 and N=50 shell closures. This study will provide information on the double-magicity of $^{56}$Ni and $^{78}$Ni, both at the extremes of nuclear stability. It will provide evidence on the suggested inversion of ground state spin around A$\\approx$74, due to the monopole migration of the $\\pi f_{5/2}$ level. The collinear laser spectroscopy technique will be used, which furthermore provides information on the changes in mean square charge radii between both neutron shell closures, probing a possible onset of deformation in this region.
Energy Technology Data Exchange (ETDEWEB)
Kath, Matthias
2009-11-06
In this thesis the experimental study of the spin dynamics of solid {sup 3}He is described. By means of magnetization measurements above 3 mK a Curie-Weiss behaviour was found with {theta}{sub W}{approx}2.1 mK and by this an order parameter of J={theta}{sub W}k{sub B}/{approx}-0.5 Kk{sub B} was observed, while in the range of 1 to 3 mK a pure Curie behaviour was found. By means of NMR measurements the values of {tau}{sub 1}(6 mK)=240 ms{+-}12 ms and {tau}{sub 1}(1 mK){approx} 40 ms were determined, while spin-echo measurements yielded the spin-spin relaxation time {tau}{sub 2}(6 mK)=4540 {mu}s{+-}140 {mu}s. Furthermore neutron scattering studies were performed. (HSI)
Chang, Zhiwei; Halle, Bertil
2016-02-28
In aqueous systems with immobilized macromolecules, including biological tissue, the longitudinal spin relaxation of water protons is primarily induced by exchange-mediated orientational randomization (EMOR) of intra- and intermolecular magnetic dipole-dipole couplings. We have embarked on a systematic program to develop, from the stochastic Liouville equation, a general and rigorous theory that can describe relaxation by the dipolar EMOR mechanism over the full range of exchange rates, dipole coupling strengths, and Larmor frequencies. Here, we present a general theoretical framework applicable to spin systems of arbitrary size with symmetric or asymmetric exchange. So far, the dipolar EMOR theory is only available for a two-spin system with symmetric exchange. Asymmetric exchange, when the spin system is fragmented by the exchange, introduces new and unexpected phenomena. Notably, the anisotropic dipole couplings of non-exchanging spins break the axial symmetry in spin Liouville space, thereby opening up new relaxation channels in the locally anisotropic sites, including longitudinal-transverse cross relaxation. Such cross-mode relaxation operates only at low fields; at higher fields it becomes nonsecular, leading to an unusual inverted relaxation dispersion that splits the extreme-narrowing regime into two sub-regimes. The general dipolar EMOR theory is illustrated here by a detailed analysis of the asymmetric two-spin case, for which we present relaxation dispersion profiles over a wide range of conditions as well as analytical results for integral relaxation rates and time-dependent spin modes in the zero-field and motional-narrowing regimes. The general theoretical framework presented here will enable a quantitative analysis of frequency-dependent water-proton longitudinal relaxation in model systems with immobilized macromolecules and, ultimately, will provide a rigorous link between relaxation-based magnetic resonance image contrast and molecular parameters
Sariciftci, Serdar; Werner, Andreas; Grupp, Arthur; Mehring, Michael; Götz, Günther; Bäuerle, Peter; Effenberger, Franz
1992-01-01
Studies on the spin distribution in the radical state of anthracene-σ bridge viologen supermolecules with different bridge units are reported. Electronnuclear double resonance experiments (ENDOR) were performed on electrochemically reduced molecules. Proton hyperfine coupling constants at different molecular sites were obtained and are discussed in detail. The experimentally determined values are compared with quantum chemical calculations of the INDO type. The observed spin distribution...
Directory of Open Access Journals (Sweden)
Venus Singh Mithu
Full Text Available Two-dimensional (13C-(13C correlation experiments are widely employed in structure determination of protein assemblies using solid-state nuclear magnetic resonance. Here, we investigate the process of (13C-(13C magnetisation transfer at a moderate magic-angle-spinning frequency of 30 kHz using some of the prominent second-order dipolar recoupling schemes. The effect of isotropic chemical-shift difference and spatial distance between two carbons and amplitude of radio frequency on (1H channel on the magnetisation transfer efficiency of these schemes is discussed in detail.
Bouchard, M.; Davis, J H; Auger, M.
1995-01-01
One- and two-dimensional solid-state 1H nuclear magnetic resonance spectra of gramicidin A incorporated in a dimyristoylphosphatidylcholine membrane have been obtained with use of high-speed magic angle spinning. By rotating the sample at 13 kHz, it is possible to observe signals in the 1H spectra between 6.0 and 9.0 ppm attributable to the aromatic protons of the tryptophan residues and the formyl group proton of gramicidin A. Two-dimensional solid-state COSY spectra provided information for...
Guzey, V.
2000-01-01
We consider the effect of nuclear shadowing in polarized deep inelastic scattering (DIS) on ^6LiD at small Bjorken x and its relevance to the extraction of the deuteron spin structure function g_{1}^{d}(x,Q^2). Using models, which describe nuclear shadowing in unpolarized DIS, we demonstrate that the nuclear shadowing correction to g_{1}^{d}(x,Q^2) is significant.
Single spin magnetic resonance
Wrachtrup, Jörg; Finkler, Amit
2016-08-01
Different approaches have improved the sensitivity of either electron or nuclear magnetic resonance to the single spin level. For optical detection it has essentially become routine to observe a single electron spin or nuclear spin. Typically, the systems in use are carefully designed to allow for single spin detection and manipulation, and of those systems, diamond spin defects rank very high, being so robust that they can be addressed, read out and coherently controlled even under ambient conditions and in a versatile set of nanostructures. This renders them as a new type of sensor, which has been shown to detect single electron and nuclear spins among other quantities like force, pressure and temperature. Adapting pulse sequences from classic NMR and EPR, and combined with high resolution optical microscopy, proximity to the target sample and nanoscale size, the diamond sensors have the potential to constitute a new class of magnetic resonance detectors with single spin sensitivity. As diamond sensors can be operated under ambient conditions, they offer potential application across a multitude of disciplines. Here we review the different existing techniques for magnetic resonance, with a focus on diamond defect spin sensors, showing their potential as versatile sensors for ultra-sensitive magnetic resonance with nanoscale spatial resolution.
International Nuclear Information System (INIS)
We report a novel method of measuring the spin polarization of alkali-metal atoms by detecting the NMR frequency shifts of noble gases. We calculated the profile of 87Rb D1 line absorption cross sections. We then measured the absorption profile of the sample cell, from which we calculated the 87Rb number densities at different temperatures. Then we measured the frequency shifts resulted from the spin polarization of the 87Rb atoms and calculated its polarization degrees at different temperatures. The behavior of frequency shifts versus temperature in experiment was consistent with theoretical calculation, which may be used as compensative signal for the NMRG closed-loop control system
Hnybida, Jeff
2016-10-01
We formulate the spin foam representation of discrete SU(2) gauge theory as a product of vertex amplitudes each of which is the spin network generating function of the boundary graph dual to the vertex. In doing so the sums over spins have been carried out. The boundary data of each n-valent node is explicitly reduced with respect to the local gauge invariance and has a manifest geometrical interpretation as a framed polyhedron of fixed total area. Ultimately, sums over spins are traded for contour integrals over simple poles and recoupling theory is avoided using generating functions.
International Nuclear Information System (INIS)
In a first part, autocorrelation functions are calculated taking into account the symmetry of molecular motions by group theoretical techniques. This very general calculation method is then used to evaluate the NMR spin-lattice relaxation times T1 and T1p as a function of the relative orientations of the magnetic field, the crystal and the rotation axis, in particular for cyclic, dihedral and cubic groups. Models of molecular reorientations such as jumps between a finite number of allowed orientations, rotational diffusion and superimposed reorientations are all investigated with the same formalism. In part two, the effect of the coherent excitation of spins, by multipulse sequences of the WHH-4 type, on the evolution of the heat capacity and spin temperature of the dipolar reservoir is analysed. It is shown both theoretically and experimentally that adiabatic (reversible) reduction of the dipolar Hamiltonian and its spin temperature is obtained when the amplitude of pulses (rotation angle) is slowly raised. The sudden switching on and off of the HW-8 sequence is then shown to lead to the same reversible reduction in a shorter time. It is also shown that, by this way, sensibility and selectivity of double resonance measurements of weak gyromagnetic ratio nuclei are strongly increased. This is experimentally illustrated in some cases. (author)
Directory of Open Access Journals (Sweden)
X. H. Liu
2015-10-01
Full Text Available We report a novel method of measuring the spin polarization of alkali-metal atoms by detecting the NMR frequency shifts of noble gases. We calculated the profile of 87Rb D1 line absorption cross sections. We then measured the absorption profile of the sample cell, from which we calculated the 87Rb number densities at different temperatures. Then we measured the frequency shifts resulted from the spin polarization of the 87Rb atoms and calculated its polarization degrees at different temperatures. The behavior of frequency shifts versus temperature in experiment was consistent with theoretical calculation, which may be used as compensative signal for the NMRG closed-loop control system.
Energy Technology Data Exchange (ETDEWEB)
Liu, X. H.; Luo, H.; Qu, T. L., E-mail: qutianliang@nudt.edu.cn; Yang, K. Y.; Ding, Z. C. [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)
2015-10-15
We report a novel method of measuring the spin polarization of alkali-metal atoms by detecting the NMR frequency shifts of noble gases. We calculated the profile of {sup 87}Rb D1 line absorption cross sections. We then measured the absorption profile of the sample cell, from which we calculated the {sup 87}Rb number densities at different temperatures. Then we measured the frequency shifts resulted from the spin polarization of the {sup 87}Rb atoms and calculated its polarization degrees at different temperatures. The behavior of frequency shifts versus temperature in experiment was consistent with theoretical calculation, which may be used as compensative signal for the NMRG closed-loop control system.
Nuclear spin-lattice relaxation at field-induced level crossings in a Cr8F8 pivalate single crystal
Yamamoto, Shoji
2016-01-01
We construct a microscopic theory for the proton spin-lattice relaxation-rate 1 / T1 measurements around field-induced level crossings in a single crystal of the trivalent chromium ion wheel complex [Cr8F8(OOCtBu)16] at sufficiently low temperatures [E. Micotti et al., Phys. Rev. B 72 (2005) 020405(R)]. Exactly diagonalizing a well-equipped spin Hamiltonian for the individual clusters and giving further consideration to their possible interactions, we reveal the mechanism of 1 / T1 being single-peaked normally at the first level crossing but double-peaked intriguingly around the second level crossing. We wipe out the doubt about poor crystallization and find out a solution-intramolecular alternating Dzyaloshinsky-Moriya interaction combined with intermolecular coupling of antiferromagnetic character, each of which is so weak as several tens of mK in magnitude.
Lomzov, Alexander A; Sviridov, Eugeniy A; Shernuykov, Andrey V; Shevelev, Georgiy Yu; Pyshnyi, Dmitrii V; Bagryanskaya, Elena G
2016-06-16
Pulse dipole-dipole electron paramagnetic resonance (EPR) spectroscopy (double electron-electron resonance [DEER] or pulse electron-electron double resonance [PELDOR] and double quantum coherence [DQC]) allows for measurement of distances in biomolecules and can be used at low temperatures in a frozen solution. Recently, the possibility of distance measurement in a nucleic acid at a physiological temperature using pulse EPR was demonstrated. In these experiments, triarylmethyl (TAM) radicals with long memory time of the electron spin served as a spin label. In addition, the duplex was immobilized on modified silica gel particles (Nucleosil DMA); this approach enables measurement of interspin distances close to 4.5 nm. Nevertheless, the possible influence of TAM on the structure of a biopolymer under study and validity of the data obtained by DQC are debated. In this paper, a combination of molecular dynamics (MD) and nuclear magnetic resonance (NMR) methods was used for verification of interspin distances measured by the X-band DQC method. NMR is widely used for structural analysis of biomolecules under natural conditions (room temperature and an aqueous solution). The ultraviolet (UV) melting method and thermal series (1)H NMR in the range 5-95 °C revealed the presence of only the DNA duplex in solution at oligonucleotide concentrations 1 μM to 1.1 mM at temperatures below 40 °C. The duplex structures and conformation flexibility of native and TAM-labeled DNA complexes obtained by MD simulation were the same as the structure obtained by NMR refinement. Thus, we showed that distance measurements at physiological temperatures by the X-band DQC method allow researchers to obtain valid structural information on an unperturbed DNA duplex using terminal TAM spin labels.
Furuya, K; Hincelin, U; Hassel, G E; Bergin, E A; Vasyunin, A I; Herbst, Eric
2015-01-01
We investigate the water deuteration ratio and ortho-to-para nuclear spin ratio of H2 (OPR(H2)) during the formation and early evolution of a molecular cloud, following the scenario that accretion flows sweep and accumulate HI gas to form molecular clouds. We follow the physical evolution of post-shock materials using a one-dimensional shock model, with post-processing gas-ice chemistry simulations. This approach allows us to study the evolution of the OPR(H2) and water deuteration ratio without an arbitrary assumption concerning the initial molecular abundances, including the initial OPR(H2). When the conversion of hydrogen into H2 is almost complete, the OPR(H2) is already much smaller than the statistical value of three due to the spin conversion in the gas phase. As the gas accumulates, the OPR(H2) decreases in a non-equilibrium manner. We find that water ice can be deuterium-poor at the end of its main formation stage in the cloud, compared to water vapor observed in the vicinity of low-mass protostars w...
Directory of Open Access Journals (Sweden)
Piotto Martial
2012-01-01
Full Text Available Abstract Introduction Providing information on cancerous tissue samples during a surgical operation can help surgeons delineate the limits of a tumoral invasion more reliably. Here, we describe the use of metabolic profiling of a colon biopsy specimen by high resolution magic angle spinning nuclear magnetic resonance spectroscopy to evaluate tumoral invasion during a simulated surgical operation. Case presentation Biopsy specimens (n = 9 originating from the excised right colon of a 66-year-old Caucasian women with an adenocarcinoma were automatically analyzed using a previously built statistical model. Conclusions Metabolic profiling results were in full agreement with those of a histopathological analysis. The time-response of the technique is sufficiently fast for it to be used effectively during a real operation (17 min/sample. Metabolic profiling has the potential to become a method to rapidly characterize cancerous biopsies in the operation theater.
International Nuclear Information System (INIS)
The licensing procedures process of nuclear plants features compulsory steps which bring about a thorough exam of the commands control system. This analysis accounts for the aspects linked to technologies (integrated circuits, software packages) which have been chosen by the manufacturer for the programmed systems in charge of safety functions. Important innovations have been introduced in terms of design and manufacturing processes of safety systems of 1400 MWe pressurized water reactors, more precisely for the integrated numerical protection system (SPIN). The methodology used by the IPSN for the exam of the software of this system is presented in the communication. This methodology leads the IPSN to carry out studies and developments of tools keeping in sight as their main goal to bring substantial help to analysis. (authors). 2 refs
Lopez, G V
2012-01-01
We study the simulation of a single qubit rotation and Controlled-Not gate in a solid state one-dimensional chain of nuclear spins system interacting weakly through an Ising type of interaction with a modular component of the magnetic field in the z-direction, characterized by $B_z(z,t)=Bo(z)\\cos\\delta t$. These qubits are subjected to electromagnetic pulses which determine the transition in the one or two qubits system. We use the fidelity parameter to determine the performance of the Not (N) gate and Controlled-Not (CNOT) gate as a function of the frequency parameter $\\delta$. We found that for $|\\delta|\\le 10^{-3} MHz$, these gates still have good fidelity.
Righi, Valeria; Parenti, Francesca; Tugnoli, Vitaliano; Schenetti, Luisa; Mucci, Adele
2015-09-30
Intact Crocus sativus petals were studied for the first time by high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy, revealing the presence of kinsenoside (2) and goodyeroside A (3), together with 3-hydroxy-γ-butyrolactone (4). These findings were confirmed by HR-NMR analysis of the ethanol extract of fresh petals and showed that, even though carried out rapidly, partial hydrolysis of glucopyranosyloxybutanolides occurs during extraction. On the other hand, kaempferol 3-O-sophoroside (1), which is "NMR-silent" in intact petals, is present in extracts. These results suggest to evaluate the utilization of saffron petals for phytopharmaceutical and nutraceutical purposes to exploit a waste product of massive production of commercial saffron and point to the application of HR-MAS NMR for monitoring bioactive compounds directly on intact petals, avoiding the extraction procedure and the consequent hydrolysis reaction.
Isoscalar spin transition in nuclei
Energy Technology Data Exchange (ETDEWEB)
Tomasi-Gustafsson, E. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France); Morlet, M.; Willis, A.; Marty, N. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Baker, F.T. [Georgia Univ., Athens, GA (United States); Beatty, D.; Edwards, G.W.R.; Glashausser, C. [Rutgers--the State Univ., Piscataway, NJ (United States); Djalali, C. [South Carolina Univ., Columbia, SC (United States). Dept. of Physics and Astronomy; Duchazeaubeneix, J.C. [Laboratoire National Saturne - Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)
1992-12-31
The study of the nuclear spin response gives a very deep insight in the magnetic properties of a nucleus. The spin-flip probability measured in inelastic scattering is a robust variable rich of information on the spin response. A study of the inelastic deuteron scattering is presented, where the isoscalar spin component of the nuclear response has been isolated for the first time. This has been possible with the 400 MeV polarized deuteron beam of Saturne and the measurement of the polarization of the outgoing deuteron with the polarimeter POMME. (author) 6 refs.; 7 figs.
Energy Technology Data Exchange (ETDEWEB)
Hu, Jian Zhi; Hu, Mary Y.; Townsend, Mark R.; Lercher, Johannes A.; Peden, Charles H. F.
2015-10-06
Re-usable ceramic magic angle spinning (MAS) NMR rotors constructed of high-mechanic strength ceramics are detailed that include a sample compartment that maintains high pressures up to at least about 200 atmospheres (atm) and high temperatures up to about least about 300.degree. C. during operation. The rotor designs minimize pressure losses stemming from penetration over an extended period of time. The present invention makes possible a variety of in-situ high pressure, high temperature MAS NMR experiments not previously achieved in the prior art.
Spin Echo of a Single Electron Spin in a Quantum Dot
Koppens, F.H.L.; Nowack, K.C.; Vandersypen, L.M.K.
2008-01-01
We report a measurement of the spin-echo decay of a single electron spin confined in a semiconductor quantum dot. When we tip the spin in the transverse plane via a magnetic field burst, it dephases in 37 ns due to the Larmor precession around a random effective field from the nuclear spins in the h
Sahoo, B K; Das, B P; Sakemi, Y
2015-01-01
Employing the relativistic coupled-cluster method, comparative studies of the parity non-conserving electric dipole amplitudes for the $7s \\ ^2S_{1/2} \\rightarrow 6d \\ ^2D_{5/2}$ transitions in $^{210}$Fr and $^{211}$Fr isotopes have been carried out. It is found that these transition amplitudes, sensitive only to the nuclear spin dependent effects, are enhanced by more than 3 orders compared to the low-lying $S-D_{5/2}$ transitions in Ba$^+$ and Ra$^+$ owing to the very large contributions from the electron core-polarization effects in Fr. This translates to a relatively large and, in principle, measurable induced light shift, which would be a signature of nuclear spin dependent parity nonconservation that is dominated by the nuclear anapole moment in a heavy atom like Fr. A plausible scheme to measure this quantity using the Cyclotron and Radioisotope Center (CYRIC) facility at Tohoku University has been outlined.
International Nuclear Information System (INIS)
Crystalline products of sodium germanate glasses system with composition from 10 mol% to 50 mol% Na2O have been investigated using 23Na magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and x-ray diffraction (XRD). Fitting of the 23Na NMR spectra of the crystalline phases concerning different crystallographically sodium atom in sodium germanate system are reasonably reproducible as observed by the spectra obtained. The line shape simulations of the 23Na NMR spectra yielded NMR quadrupolar parameters such as nuclear quadrupole coupling constants (CQ), asymmetry parameters (η), and isotropic chemical shifts (δi). 23Na NMR isotropic chemical shift may also provide further information on the structural environment of the sodium atom. A simple correlation between structure and NMR parameters to be tested can be used to probe the structure of sodium germanate glasses. The experimental 23Na chemical shifts correlate well with an empirical shift parameter based on the total oxygen-cation bond valence and Na-O distances of all oxygen atoms in the first coordination sphere of the sodium cation. In this study the different phases in the sodium germanate system were identified. These results show that 23Na NMR can provide examples of the types of structural information for sodium germanate system. (Author)
The phase diagram and the magnetic structure of nuclear spins in elemental copper below 60 nK
DEFF Research Database (Denmark)
Siemensmeyer, K.; Steiner, M.; Weinfurther, H.;
1992-01-01
The phase diagram for nuclear magnetic order is elemental copper and the corresponding ordering vectors were investigated by neutron diffraction at nanokelvin temperatures. The intermediate phase is characterized by an ordering vector (O 2/3 2/3). This is the first time that this type of order is...... is observed in an fcc antiferromagnet....
Voinov, A. V.; Grimes, S. M.; Brune, C. R.; Bürger, A.; Görgen, A.; Guttormsen, M.; Larsen, A. C.; Massey, T. N.; Siem, S.
2013-11-01
Proton double-differential cross sections from 59Co(α,p)62Ni, 57Fe(α,p)60Co, 56Fe(7Li,p)62Ni, and 55Mn(6Li,p)60Co reactions have been measured with 21-MeV α and 15-MeV lithium beams. Cross sections have been compared against calculations with the empire reaction code. Different input level density models have been tested. It was found that the Gilbert and Cameron [A. Gilbert and A. G. W. Cameron, Can. J. Phys.0008-420410.1139/p65-139 43, 1446 (1965)] level density model is best to reproduce experimental data. Level densities and spin cutoff parameters for 62Ni and 60Co above the excitation energy range of discrete levels (in continuum) have been obtained with a Monte Carlo technique. Excitation energy dependencies were found to be inconsistent with the Fermi-gas model.
Valenzuela, Sergio O; Saitoh, Eiji; Kimura, Takashi
2012-01-01
In a new branch of physics and technology called spin-electronics or spintronics, the flow of electrical charge (usual current) as well as the flow of electron spin, the so-called 'spin current', are manipulated and controlled together. This book provides an introduction and guide to the new physics and application of spin current.
Cho, Herman
2016-09-01
Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3 / 2 , 5 / 2 , 7 / 2, and 9 / 2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed.
Newman, Ezra T.; Silva-Ortigoza, Gilberto
2005-01-01
We show how to define and go from the spin-s spherical harmonics to the tensorial spin-s harmonics. These quantities, which are functions on the sphere taking values as Euclidean tensors, turn out to be extremely useful for many calculations in General Relativity. In the calculations, products of these functions, with their needed decompositions which are given here, often arise naturally.
International Nuclear Information System (INIS)
This paper introduces the experiment, where the function of spin-isospin symmetry inside atomic nuclei was observed through Gamow-Teller (GT) transition. In the experiment, the authors used 56Ni (p,n) reaction as inverse kinematics using the intermediate energy unstable nucleus beams, and missing mass method to obtain the GT transition intensity distribution of unstable nucleus 56Ni. In the missing mass method, by measuring the four momentum vector (kinetic energy and emission direction) of the recoil neutrons from the probe particles produced in the (p,n) reaction, excitation energy and scattering angle are determined. When the experimental results were compared with the full-fp shell model calculation called as GXPFiL interaction, two peaks characteristic of the experimental data were well reproduced. In the GT transition strength distribution of 56Ni, half of the intensities concentrated in the peaks of the low-energy side, and explanation was impossible based on the effect of particle vacancy interaction. However, in N=Z nuclei, particle-particle interactions was emphasized, which suggests the situation for some intensities to make the peaks at the low excitation energy side. (A.O.)
Energy Technology Data Exchange (ETDEWEB)
Sigl, A.
2007-12-28
A methyl group is an outstanding quantum system due to its special symmetry properties. The threefold rotation around one of its bond is isomorphic to the group of even permutations of the remaining protons, a property which imposes severe quantum restrictions on the system, for instance a strict correlation of rotational states with nuclear spin states. The resulting long lifetimes of the rotational tunneling states of the methyl group can be exploited for applying certain high resolution optical techniques, like hole burning or single molecule spectroscopy to optically switch the methyl group from one tunneling state to another therebye changing the nuclear spin of the protons. One goal of the thesis was to perform this switching in single methyl groups. To this end the methyl group was attached to a chromophoric system, in the present case terrylene, which is well suited for single molecule spectroscopy as well as for hole burning. Experiments were performed with the bare terrylene molecule in a hexadecane lattice which served as a reference system, with alphamethyl terrylene and betamethyl terrylene, both embedded in hexadecane, too. A single molecular probe is a highly sensitive detector for dynamic lattice instabilities. Already the bare terrylene probe showed a wealth of interesting local dynamic effects of the hexadecane lattice which could be well acounted for by the assumption of two nearly degenerate sites with rather different optical and thermal properties, all of which could be determined in a quantitative fashion. As to the methylated terrylene systems, the experiments verified that for betamethyl terrylene it is indeed possible to measure rotational tunneling events in single methyl groups. However, the spectral patterns obtained was much more complicated than expected pointing to the presence of three spectroscopically different methyl groups. In order to achieve a definite assignement, molecular mechanics simulations of the terrylene probes in the
Energy Technology Data Exchange (ETDEWEB)
Cho, Herman
2016-09-01
Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2, 5/2, 7/2, and 9/2. These results may be used to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences, Heavy Element Chemistry program.
International Nuclear Information System (INIS)
This document proposes a presentation and discussion of the main notions, issues, principles, or characteristics related to nuclear energy: radioactivity (presence in the environment, explanation, measurement, periods and activities, low doses, applications), fuel cycle (front end, mining and ore concentration, refining and conversion, fuel fabrication, in the reactor, back end with reprocessing and recycling, transport), the future of the thorium-based fuel cycle (motivations, benefits and drawbacks), nuclear reactors (principles of fission reactors, reactor types, PWR reactors, BWR, heavy-water reactor, high temperature reactor of HTR, future reactors), nuclear wastes (classification, packaging and storage, legal aspects, vitrification, choice of a deep storage option, quantities and costs, foreign practices), radioactive releases of nuclear installations (main released radio-elements, radioactive releases by nuclear reactors and by La Hague plant, gaseous and liquid effluents, impact of releases, regulation), the OSPAR Convention, management and safety of nuclear activities (from control to quality insurance, to quality management and to sustainable development), national safety bodies (mission, means, organisation and activities of ASN, IRSN, HCTISN), international bodies, nuclear and medicine (applications of radioactivity, medical imagery, radiotherapy, doses in nuclear medicine, implementation, the accident in Epinal), nuclear and R and D (past R and D programmes and expenses, main actors in France and present funding, main R and D axis, international cooperation)
Mazzei, Pierluigi; Vinale, Francesco; Woo, Sheridan Lois; Pascale, Alberto; Lorito, Matteo; Piccolo, Alessandro
2016-05-11
Trichoderma fungi release 6-pentyl-2H-pyran-2-one (1) and harzianic acid (2) secondary metabolites to improve plant growth and health protection. We isolated metabolites 1 and 2 from Trichoderma strains, whose different concentrations were used to treat seeds of Solanum lycopersicum. The metabolic profile in the resulting 15 day old tomato leaves was studied by high-resolution magic-angle-spinning nuclear magnetic resonance (HRMAS NMR) spectroscopy directly on the whole samples without any preliminary extraction. Principal component analysis (PCA) of HRMAS NMR showed significantly enhanced acetylcholine and γ-aminobutyric acid (GABA) content accompanied by variable amount of amino acids in samples treated with both Trichoderma secondary metabolites. Seed germination rates, seedling fresh weight, and the metabolome of tomato leaves were also dependent upon doses of metabolites 1 and 2 treatments. HRMAS NMR spectroscopy was proven to represent a rapid and reliable technique for evaluating specific changes in the metabolome of plant leaves and calibrating the best concentration of bioactive compounds required to stimulate plant growth.
Shingledecker, Christopher N; Gal, Romane Le; Oberg, Karin I; Hincelin, Ugo; Herbst, Eric
2016-01-01
The chemistry of dense interstellar regions was analyzed using a time-dependent gas-grain astrochemical simulation and a new chemical network that incorporates deuterated chemistry taking into account nuclear spin-states for the hydrogen chemistry and its deuterated isotopologues. With this new network, the utility of the [HCO$^+$]/[DCO$^+$] abundance ratio as a probe of the cosmic ray ionization rate has been reexamined, with special attention paid to the effect of the initial value of the molecular hydrogen ortho-to-para ratio (OPR). After discussing the use of the probe for cold cores, we then compare our results with previous theoretical and observational results for a molecular cloud close to the supernova remnant W51C, which is thought to have an enhanced cosmic ray ionization rate $\\zeta$ caused by the nearby $\\gamma$-ray source. In addition, we attempt to use our approach to estimate the cosmic ray ionization rate for L1174, a dense core with an embedded star. Beyond the previously known sensitivity o...
Maria, Roberta M; Altei, Wanessa F; Andricopulo, Adriano D; Becceneri, Amanda B; Cominetti, Márcia R; Venâncio, Tiago; Colnago, Luiz A
2015-11-01
(1)H high-resolution magic angle spinning nuclear magnetic resonance ((1)H HR-MAS NMR) spectroscopy was used to analyze the metabolic profile of an intact non-tumor breast cell line (MCF-10A) and intact breast tumor cell lines (MCF-7 and MDA-MB-231). In the spectra of MCF-10A cells, six metabolites were assigned, with glucose and ethanol in higher concentrations. Fifteen metabolites were assigned in MCF-7 and MDA-MB-231 (1)H HR-MAS NMR spectra. They did not show glucose and ethanol, and the major component in both tumor cells was phosphocholine (higher in MDA-MB-231 than in MCF-7), which can be considered as a tumor biomarker of breast cancer malignant transformation. These tumor cells also show acetone signal that was higher in MDA-MB-231 cells than in MCF-7 cells. The high acetone level may be an indication of high demand for energy in MDA-MB-231 to maintain cell proliferation. The higher acetone and phosphocholine levels in MDA-MB-231 cells indicate the higher malignance of the cell line. Therefore, HR-MAS is a rapid reproducible method to study the metabolic profile of intact breast cells, with minimal sample preparation and contamination, which are critical in the analyses of slow-growth cells.
Damping of a nanocantilever by paramagnetic spins
Chudnovsky, E. M.; Garanin, D.A.
2014-01-01
We compute damping of mechanical oscillations of a cantilever that contains flipping paramagnetic spins. This kind of damping is mandated by the dynamics of the total angular momentum, spin + mechanical. Rigorous expression for the damping rate is derived in terms of measurable parameters. The effect of spins on the quality factor of the cantilever can be significant in cantilevers of small length that have large concentration of paramagnetic spins of atomic and/or nuclear origin.
Spectroscopy of composite solid-state spin environments for improved metrology with spin ensembles
Bar-Gill, Nir; Pham, Linh; Belthangady, Chinmay; Lesage, David; Cappellaro, Paola; Maze, Jeronimo; Lukin, Mikhail; Yacoby, Amir; Walsworth, Ronald
2012-02-01
For precision coherent measurements with ensembles of quantum spins the relevant Figure-of-Merit (FOM) is the product of spin density and coherence lifetime, which is generally limited by the dynamics of spin coupling to the environment. Significant effort has been invested in understanding the causes of decoherence in a diverse range of spin systems in order to increase the FOM and improve measurement sensitivity. Here, we apply a coherent spectroscopic technique to characterize the dynamics of a composite solid-state spin environment consisting of Nitrogen-Vacancy (NV) color centers in room temperature diamond coupled to baths of electronic spin (N) and nuclear spin (13C) impurities. For diamond samples with a wide range of NV densities and impurity spin concentrations we employ a dynamical decoupling technique to minimize coupling to the environment, and find similar values for the FOM, which is three orders of magnitude larger than previously achieved in any room-temperature solid-state spin system, and thus should enable greatly improved precision spin metrology. We also identify a suppression of electronic spin bath dynamics in the presence of a nuclear spin bath of sufficient nuclear spin concentration. This suppression could inform efforts to engineer samples with even larger FOM for solid-state spin ensemble metrology and collective quantum information processing.
Multifrequency spin resonance in diamond
Childress, Lilian
2010-01-01
Magnetic resonance techniques provide a powerful tool for controlling spin systems, with applications ranging from quantum information processing to medical imaging. Nevertheless, the behavior of a spin system under strong excitation remains a rich dynamical problem. In this paper, we examine spin resonance of the nitrogen-vacancy center in diamond under conditions outside the regime where the usual rotating wave approximation applies, focusing on effects of multifrequency excitation and excitation with orientation parallel to the spin quantization axis. Strong-field phenomena such as multiphoton transitions and coherent destruction of tunneling are observed in the spectra and analyzed via numerical and analytic theory. In addition to illustrating the response of a spin system to strong multifrequency excitation, these observations may inform techniques for manipulating electron-nuclear spin quantum registers.
Berry, John P; Roy, Upasana; Jaja-Chimedza, Asha; Sanchez, Kristel; Matysik, Joerg; Alia, A
2016-10-01
Techniques based on nuclear magnetic resonance (NMR) for imaging and chemical analyses of in vivo, or otherwise intact, biological systems are rapidly emerging and finding diverse applications within a wide range of fields. Very recently, several NMR-based techniques have been developed for the zebrafish as a model animal system. In the current study, the novel application of high-resolution magic angle spinning (HR-MAS) NMR is presented as a means of metabolic profiling of intact zebrafish embryos. Toward investigating the utility of HR-MAS NMR as a toxicological tool, these studies specifically examined metabolic changes of embryos exposed to polymethoxy-1-alkenes (PMAs)-a recently identified family of teratogenic compounds from freshwater algae-as emerging environmental contaminants. One-dimensional and two-dimensional HR-MAS NMR analyses were able to effectively identify and quantify diverse metabolites in early-stage (≤36 h postfertilization) embryos. Subsequent comparison of the metabolic profiles between PMA-exposed and control embryos identified several statistically significant metabolic changes associated with subacute exposure to the teratogen, including (1) elevated inositol as a recognized component of signaling pathways involved in embryo development; (2) increases in several metabolites, including inositol, phosphoryl choline, fatty acids, and cholesterol, which are associated with lipid composition of cell membranes; (3) concomitant increase in glucose and decrease in lactate; and (4) decreases in several biochemically related metabolites associated with central nervous system development and function, including γ-aminobutyric acid, glycine, glutamate, and glutamine. A potentially unifying model/hypothesis of PMA teratogenicity based on the data is presented. These findings, taken together, demonstrate that HR-MAS NMR is a promising tool for metabolic profiling in the zebrafish embryo, including toxicological applications.
Lorenz, Klaus; Preston, Caroline M
2002-01-01
Condensed tannins can be found in various parts of many plants. Unlike lignin there has been little study of their fate as they enter the soil organic matter pool and their influence on nutrient cycling, especially through their protein-binding properties. We extracted and characterized tannin-rich fractions from humus collected in 1998 from a black spruce [Picea mariana (Mill.) Britton et al.] forest in Canada where a previous study (1995) showed high levels (3.8% by weight) of condensed tannins. A reference tannin purified from black spruce needles was characterized by solution 13C nuclear magnetic resonance (NMR) as a pure procyanidin with mainly cis stereochemistry and an average chain length of four to five units. The colorimetric proanthocyanidin (PA) assay, standardized against the black spruce tannin, showed that both extracted humus fractions had higher tannin contents than the original humus (2.84% and 11.17% vs. 0.08%), and accounted for 32% of humus tannin content. Consistent with the results from the chemical assay, the aqueous fraction showed higher tannin signals in the 13C cross-polarization and magic-angle spinning (CPMAS) NMR spectrum than the emulsified one. As both tannin-rich humus fractions were depleted in N and high in structures derived from lignin and cutin, they did not have properties consistent with recaldtrant tannin-protein complexes proposed as a mechanism for N sequestration in humus. Further studies are needed to establish if tannin-protein structures in humus can be detected or isolated, or if tannins contribute to forest management problems observed in these ecosystems by binding to and slowing down the activity of soil enzymes.
Energy Technology Data Exchange (ETDEWEB)
Benjamin Michael Meyer
2003-05-31
As time progresses, the world is using up more of the planet's natural resources. Without technological advances, the day will eventually arrive when these natural resources will no longer be sufficient to supply all of the energy needs. As a result, society is seeing a push for the development of alternative fuel sources such as wind power, solar power, fuel cells, and etc. These pursuits are even occurring in the state of Iowa with increasing social pressure to incorporate larger percentages of ethanol in gasoline. Consumers are increasingly demanding that energy sources be more powerful, more durable, and, ultimately, more cost efficient. Fast Ionic Conducting (FIC) glasses are a material that offers great potential for the development of new batteries and/or fuel cells to help inspire the energy density of battery power supplies. This dissertation probes the mechanisms by which ions conduct in these glasses. A variety of different experimental techniques give a better understanding of the interesting materials science taking place within these systems. This dissertation discusses Nuclear Magnetic Resonance (NMR) techniques performed on FIC glasses over the past few years. These NMR results have been complimented with other measurement techniques, primarily impedance spectroscopy, to develop models that describe the mechanisms by which ionic conduction takes place and the dependence of the ion dynamics on the local structure of the glass. The aim of these measurements was to probe the cause of a non-Arrhenius behavior of the conductivity which has been seen at high temperatures in the silver thio-borosilicate glasses. One aspect that will be addressed is if this behavior is unique to silver containing fast ion conducting glasses. more specifically, this study will determine if a non-Arrhenius correlation time, {tau}, can be observed in the Nuclear Spin Lattice Relaxation (NSLR) measurements. If so, then can this behavior be modeled with a new single
Veselý, P.; Hiyama, E.; Hrtánková, J.; Mareš, J.
2016-10-01
We introduce a mean field model based on realistic 2-body baryon interactions and calculate spectra of a set of p-shell and sd-shell Λ hypernuclei - 13ΛC, 17ΛO, 21ΛNe, 29ΛSi and 41ΛCa. The hypernuclear spectra are compared with the results of a relativistic mean field (RMF) model and available experimental data. The sensitivity of Λ single-particle energies to the nuclear core structure is explored. Special attention is paid to the effect of spin-orbit ΛN interaction on the energy splitting of the Λ single particle levels 0p3/2 and 0p1/2. In particular, we analyze the contribution of the symmetric (SLS) and the anti-symmetric (ALS) spin-orbit terms to the energy splitting. We give qualitative predictions for the calculated hypernuclei.
Veselý, P; Hrtánková, J; Mareš, J
2016-01-01
We introduce a mean field model based on realistic 2-body baryon interactions and calculate spectra of a set of p-shell and sd-shell {\\Lambda} hypernuclei - 13{\\Lambda}C, 17{\\Lambda}O, 21{\\Lambda}Ne, 29{\\Lambda}Si and 41{\\Lambda}Ca. The hypernuclear spectra are compared with the results of a relativistic mean field (RMF) model and available experimental data. The sensitivity of {\\Lambda} single-particle energies to the nuclear core structure is explored. Special attention is paid to the effect of spin-orbit {\\Lambda}N interaction on the energy splitting of the {\\Lambda} single particle levels 0p3/2 and 0p1/2. In particular, we analyze the contribution of the symmetric (SLS) and the anti-symmetric (ALS) spin-orbit terms to the energy splitting. We give qualitative predictions for the calculated hypernuclei.
Directory of Open Access Journals (Sweden)
Angel Esteban
2003-02-01
Full Text Available Abstract: The known solvent dependence of 1J(Cc,Hf and 2J(C1,Hf couplings in acetaldehyde is studied from a theoretical viewpoint based on the density functional theory approach where the dielectric solvent effect is taken into account with the polarizable continuum model. The four terms of scalar couplings, Fermi contact, paramagnetic spin orbital, diamagnetic spin orbital and spin dipolar, are calculated but the solvent effect analysis is restricted to the first term since for both couplings it is by far the dominant contribution. Experimental trends of ÃŽÂ”1J(Cc,Hf and ÃŽÂ”2J(C1,Hf Vs ÃŽÂµ (the solvent dielectric constant are correctly reproduced although they are somewhat underestimated. Specific interactions between solute and solvent molecules are studied for dimethylsulfoxide, DMSO, solutions considering two different one-to-one molecular complexes between acetaldehyde and DMSO. They are determined by interactions of type C=O---H---C and S=O---H---C, and the effects of such interactions on 1J(Cc,Hf and 2J(C1,Hf couplings are analyzed. Even though only in a semiquantitative way, it is shown that the effect of such interactions on the solvent effects, of ÃŽÂ”1J(Cc,Hf and ÃŽÂ”2J(C1,Hf, tend to improve the agreement between calculated and experimental values. These results seem to indicate that a continuum dielectric model has not enough flexibility for describing quantitatively solvent effects on spin-spin couplings. Apparently, even for relatively weak hydrogen bonding, the contribution from Ã¢Â€ÂœdirectÃ¢Â€Â interactions is of the same order of magnitude as the Ã¢Â€ÂœdielectricÃ¢Â€Â effect.
Bovier, Anton
2007-01-01
Spin glass theory is going through a stunning period of progress while finding exciting new applications in areas beyond theoretical physics, in particular in combinatorics and computer science. This collection of state-of-the-art review papers written by leading experts in the field covers the topic from a wide variety of angles. The topics covered are mean field spin glasses, including a pedagogical account of Talagrand's proof of the Parisi solution, short range spin glasses, emphasizing the open problem of the relevance of the mean-field theory for lattice models, and the dynamics of spin glasses, in particular the problem of ageing in mean field models. The book will serve as a concise introduction to the state of the art of spin glass theory, usefull to both graduate students and young researchers, as well as to anyone curious to know what is going on in this exciting area of mathematical physics.
Lefort, Ronan; Bordat, Patrice; Cesaro, Attilio; Descamps, Marc
2007-01-01
This paper uses chemical shift surfaces to simulate experimental C13 cross polarization magic angle spinning spectra for amorphous solid state disaccharides, paying particular attention to the glycosidic linkage atoms in trehalose, sucrose, and lactose. The combination of molecular mechanics with density functional theory/gauge invariant atomic orbital ab initio methods provides reliable structural information on the conformational distribution in the glass. The results are interpreted in terms of an enhanced flexibility that trehalose possesses in the amorphous solid state, at least on the time scale of C13 nuclear magnetic resonance measurements. Implications of these findings for the fragility of trehalose glass and bioprotectant action are discussed.
Spin polarization transfer by the radical pair mechanism
Energy Technology Data Exchange (ETDEWEB)
Zarea, Mehdi, E-mail: m-zarea@northwestern.edu; Ratner, Mark A.; Wasielewski, Michael R. [Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113 (United States)
2015-08-07
In a three-site representation, we study a spin polarization transfer from radical pair spins to a nearby electron or nuclear spin. The quantum dynamics of the radical pair spins is governed by a constant exchange interaction between the radical pair spins which have different Zeeman frequencies. Radical pair spins can recombine to the singlet ground state or to lower energy triplet states. It is then shown that the coherent dynamics of the radical pair induces spin polarization on the nearby third spin in the presence of a magnetic field. The spin polarization transfer depends on the difference between Zeeman frequencies, the singlet and triplet recombination rates, and on the exchange and dipole-dipole interactions between the different spins. In particular, the sign of the polarization depends on the exchange coupling between radical pair spins and also on the difference between singlet and triplet recombination rate constants.
Kawamura, M.; Takahashi, H; Masubuchi, S.; Hashimoto, Y.; Katsumoto, S.; Hamaya, K.; Machida, T.
2007-01-01
Nuclear spins are polarized electrically in a breakdown regime of an odd-integer quantum Hall effect (QHE). Electron excitation to the upper Landau subband with the opposite spin polarity flips nuclear spins through the hyperfine interaction. The polarized nuclear spins reduce the spin-splitting energy and accelerate the QHE breakdown. The Knight shift of the nuclear spins is also measured by tuning electron density during the irradiation of radio-frequency magnetic fields.
Buhrman, Robert; Daughton, James; Molnár, Stephan; Roukes, Michael
2004-01-01
This report is a comparative review of spin electronics ("spintronics") research and development activities in the United States, Japan, and Western Europe conducted by a panel of leading U.S. experts in the field. It covers materials, fabrication and characterization of magnetic nanostructures, magnetism and spin control in magnetic nanostructures, magneto-optical properties of semiconductors, and magnetoelectronics and devices. The panel's conclusions are based on a literature review and a series of site visits to leading spin electronics research centers in Japan and Western Europe. The panel found that Japan is clearly the world leader in new material synthesis and characterization; it is also a leader in magneto-optical properties of semiconductor devices. Europe is strong in theory pertaining to spin electronics, including injection device structures such as tunneling devices, and band structure predictions of materials properties, and in development of magnetic semiconductors and semiconductor heterost...
Purification of an unpolarized spin ensemble into entangled singlet pairs
Greiner, Johannes N; Wrachtrup, Jörg
2016-01-01
Dynamical polarization of nuclear spin ensembles is of central importance for magnetic resonance studies, precision sensing and for applications in quantum information theory. Here we propose a scheme to generate long-lived singlet pairs in an unpolarized nuclear spin ensemble which is dipolar coupled to the electron spins of a Nitrogen Vacancy center in diamond. The quantum mechanical back-action induced by frequent spin-selective readout of the NV centers allows the nuclear spins to pair up into maximally entangled singlet pairs. Counterintuitively, the robustness of the pair formation to dephasing noise improves with increasing size of the spin ensemble. We also show how the paired nuclear spin state allows for enhanced sensing capabilities of NV centers in diamond.
Aucar, I Agustín; Gómez, Sergio S; Melo, Juan I; Giribet, Claudia C; Ruiz de Azúa, Martín C
2013-04-01
In the present work, numerical results of the nuclear spin-rotation (SR) tensor in the series of compounds HX (X = H,F,Cl,Br,I) within relativistic 4-component expressions obtained by Aucar et al. [J. Chem. Phys. 136, 204119 (2012)] are presented. The SR tensors of both the H and X nuclei are discussed. Calculations were carried out within the relativistic Linear Response formalism at the Random Phase Approximation with the DIRAC program. For the halogen nucleus X, correlation effects on the non-relativistic values are shown to be of similar magnitude and opposite sign to relativistic effects. For the light H nucleus, by means of the linear response within the elimination of the small component approach it is shown that the whole relativistic effect is given by the spin-orbit operator combined with the Fermi contact operator. Comparison of "best estimate" calculated values with experimental results yield differences smaller than 2%-3% in all cases. The validity of "Flygare's relation" linking the SR tensor and the NMR nuclear magnetic shielding tensor in the present series of compounds is analyzed. PMID:23574208
International Nuclear Information System (INIS)
Field firing of nuclear artillery shells has indicated that failures could be caused not only by the violent setback force of the explosive launch but also by the centrifugal force of the spin imparted by the gun barrel's rifling. To reduce the cost and time for obtaining test data from field launches, the spin portion of the flight environment was simulated in a test facility capable of spinning a 350-kg test specimen up to 40,000 rpm
Gordon Conference on Nuclear Research
Energy Technology Data Exchange (ETDEWEB)
Austin, S.M.
1983-09-01
Session topics were: quarks and nuclear physics; anomalons and anti-protons; the independent particle structure of nuclei; relativistic descriptions of nuclear structure and scattering; nuclear structure at high excitation; advances in nuclear astrophysics; properties of nuclear material; the earliest moments of the universe; and pions and spin excitations in nuclei.
Gordon Conference on Nuclear Research
International Nuclear Information System (INIS)
Session topics were: quarks and nuclear physics; anomalons and anti-protons; the independent particle structure of nuclei; relativistic descriptions of nuclear structure and scattering; nuclear structure at high excitation; advances in nuclear astrophysics; properties of nuclear material; the earliest moments of the universe; and pions and spin excitations in nuclei
High spin isomer beam line at RIKEN
Energy Technology Data Exchange (ETDEWEB)
Kishida, T.; Ideguchi, E.; Wu, H.Y. [Institute of Physical and Chemical Research, Saitama (Japan)] [and others
1996-12-31
Nuclear high spin states have been the subject of extensive experimental and theoretical studies. For the production of high spin states, fusion reactions are usually used. The orbital angular momentum brought in the reaction is changed into the nuclear spin of the compound nucleus. However, the maximum induced angular momentum is limited in this mechanism by the maximum impact parameter of the fusion reaction and by the competition with fission reactions. It is, therefore, difficult to populate very high spin states, and as a result, large {gamma}-detector arrays have been developed in order to detect subtle signals from such very high spin states. The use of high spin isomers in the fusion reactions can break this limitation because the high spin isomers have their intrinsic angular momentum, which can bring the additional angular momentum without increasing the excitation energy. There are two methods to use the high spin isomers for secondary reactions: the use of the high spin isomers as a target and that as a beam. A high spin isomer target has already been developed and used for several experiments. But this method has an inevitable shortcoming that only {open_quotes}long-lived{close_quotes} isomers can be used for a target: {sup 178}Hf{sup m2} (16{sup +}) with a half-life of 31 years in the present case. By developing a high spin isomer beam, the authors can utilize various short-lived isomers with a short half-life around 1 {mu}s. The high spin isomer beam line of RIKEN Accelerator Facility is a unique apparatus in the world which provides a high spin isomer as a secondary beam. The combination of fusion-evaporation reaction and inverse kinematics are used to produce high spin isomer beams; in particular, the adoption of `inverse kinematics` is essential to use short-lived isomers as a beam.
Spin-Orbit induced semiconductor spin guides
Valin-Rodriguez, Manuel; Puente, Antonio; Serra, Llorens
2002-01-01
The tunability of the Rashba spin-orbit coupling allows to build semiconductor heterostructures with space modulated coupling intensities. We show that a wire-shaped spin-orbit modulation in a quantum well can support propagating electronic states inside the wire only for a certain spin orientation and, therefore, it acts as an effective spin transmission guide for this particular spin orientation.
Adiabatic quantum computing with spin qubits hosted by molecules.
Yamamoto, Satoru; Nakazawa, Shigeaki; Sugisaki, Kenji; Sato, Kazunobu; Toyota, Kazuo; Shiomi, Daisuke; Takui, Takeji
2015-01-28
A molecular spin quantum computer (MSQC) requires electron spin qubits, which pulse-based electron spin/magnetic resonance (ESR/MR) techniques can afford to manipulate for implementing quantum gate operations in open shell molecular entities. Importantly, nuclear spins, which are topologically connected, particularly in organic molecular spin systems, are client qubits, while electron spins play a role of bus qubits. Here, we introduce the implementation for an adiabatic quantum algorithm, suggesting the possible utilization of molecular spins with optimized spin structures for MSQCs. We exemplify the utilization of an adiabatic factorization problem of 21, compared with the corresponding nuclear magnetic resonance (NMR) case. Two molecular spins are selected: one is a molecular spin composed of three exchange-coupled electrons as electron-only qubits and the other an electron-bus qubit with two client nuclear spin qubits. Their electronic spin structures are well characterized in terms of the quantum mechanical behaviour in the spin Hamiltonian. The implementation of adiabatic quantum computing/computation (AQC) has, for the first time, been achieved by establishing ESR/MR pulse sequences for effective spin Hamiltonians in a fully controlled manner of spin manipulation. The conquered pulse sequences have been compared with the NMR experiments and shown much faster CPU times corresponding to the interaction strength between the spins. Significant differences are shown in rotational operations and pulse intervals for ESR/MR operations. As a result, we suggest the advantages and possible utilization of the time-evolution based AQC approach for molecular spin quantum computers and molecular spin quantum simulators underlain by sophisticated ESR/MR pulsed spin technology.
Spin-current probe for phase transition in an insulator
Qiu, Zhiyong; Li, Jia; Hou, Dazhi; Arenholz, Elke; N'diaye, Alpha T.; Tan, Ali; Uchida, Ken-Ichi; Sato, Koji; Okamoto, Satoshi; Tserkovnyak, Yaroslav; Qiu, Z. Q.; Saitoh, Eiji
2016-08-01
Spin fluctuation and transition have always been one of the central topics of magnetism and condensed matter science. Experimentally, the spin fluctuation is found transcribed onto scattering intensity in the neutron-scattering process, which is represented by dynamical magnetic susceptibility and maximized at phase transitions. Importantly, a neutron carries spin without electric charge, and therefore it can bring spin into a sample without being disturbed by electric energy. However, large facilities such as a nuclear reactor are necessary. Here we show that spin pumping, frequently used in nanoscale spintronic devices, provides a desktop microprobe for spin transition; spin current is a flux of spin without an electric charge and its transport reflects spin excitation. We demonstrate detection of antiferromagnetic transition in ultra-thin CoO films via frequency-dependent spin-current transmission measurements, which provides a versatile probe for phase transition in an electric manner in minute devices.
Spin-current probe for phase transition in an insulator.
Qiu, Zhiyong; Li, Jia; Hou, Dazhi; Arenholz, Elke; N'Diaye, Alpha T; Tan, Ali; Uchida, Ken-Ichi; Sato, Koji; Okamoto, Satoshi; Tserkovnyak, Yaroslav; Qiu, Z Q; Saitoh, Eiji
2016-01-01
Spin fluctuation and transition have always been one of the central topics of magnetism and condensed matter science. Experimentally, the spin fluctuation is found transcribed onto scattering intensity in the neutron-scattering process, which is represented by dynamical magnetic susceptibility and maximized at phase transitions. Importantly, a neutron carries spin without electric charge, and therefore it can bring spin into a sample without being disturbed by electric energy. However, large facilities such as a nuclear reactor are necessary. Here we show that spin pumping, frequently used in nanoscale spintronic devices, provides a desktop microprobe for spin transition; spin current is a flux of spin without an electric charge and its transport reflects spin excitation. We demonstrate detection of antiferromagnetic transition in ultra-thin CoO films via frequency-dependent spin-current transmission measurements, which provides a versatile probe for phase transition in an electric manner in minute devices. PMID:27573443
Universal control and error correction in multi-qubit spin registers in diamond
Taminiau, T. H.; Cramer, J.; van der Sar, T.; Dobrovitski, V. V.; Hanson, R.
2013-01-01
Quantum registers of nuclear spins coupled to electron spins of individual solid-state defects are a promising platform for quantum information processing. Pioneering experiments selected defects with favourably located nuclear spins having particularly strong hyperfine couplings. For progress towards large-scale applications, larger and deterministically available nuclear registers are highly desirable. Here we realize universal control over multi-qubit spin registers by harnessing abundant ...
21st International Symposium on Spin Physics
Ma, Bo-Qiang; SPIN 2014; SPIN2014
2016-01-01
This special volume collected important papers written by leading experts, highlighting the latest research findings in various topics of spin phenomena in particle and nuclear physics. The contents are originated from the plenary talks at the latest symposium of the Spin Physics series (SPIN2014) which was held in Beijing, China, October 20-24, 2014.The volume also comprises a special collection of contributions in memory of the late Professor Michel Borghini, an outstanding physicist well remembered for his great contributions to the progress of high energy spin physics.
Electric probe for spin transition and fluctuation
Qiu, Zhiyong; Li, Jia; Hou, Dazhi; Arenholz, Elke; N'diaye, Alpha T.; Tan, Ali; Uchida, Ken-Ichi; Sato, Koji; Tserkovnyak, Yaroslov; Qiu, Z. Q.; Saitoh, Eiji
Spin fluctuation and transition have always been one of central topics of magnetism and condense matter science. To probe them, neutron scatterings have been used as powerful tools. A part of neutrons injected into a sample is scattered by spin fluctuation inside the sample. This process transcribes the spin fluctuation onto scattering intensity, which is commonly represented by dynamical magnetic susceptibility of the sample and is maximized at magnetic phase transitions. Importantly, a neutron carries spin without electric charge, and it thus can bring spin into a sample without being disturbed by electric energy: an advantage of neutrons, although large facilities such as a nuclear reactor is necessary. Here we show that spin pumping, frequently used in nanoscale spintronic devices, provides a desktop micro probe for spin fluctuation and transition; not only a neutron beam, spin current is also a flux of spin without an electric charge and its transport reflects spin fluctuation in a sample. We demonstrate detection of anti-ferromagnetic transition in ultra-thin CoO films via frequency dependent spin-current transmission measurements.
Strong Hyperfine-Induced Modulation of an Optically-Driven Hole Spin in an InAs Quantum Dot
Carter, Samuel G.; Economou, Sophia E.; Greilich, Alex; Barnes, Edwin; Sweeney, Timothy M.; Bracker, Allan S.; Gammon, Daniel
2013-01-01
Compared to electrons, holes in InAs quantum dots have a significantly weaker hyperfine interaction that leads to less dephasing from nuclear spins. Thus many recent studies have suggested that nuclear spins are unimportant for hole spin dynamics compared to electric field fluctuations. We show that the hole hyperfine interaction can have a strong effect on hole spin coherence measurements through a nuclear feedback effect. The nuclear polarization is generated through a unique process that i...
Brahms, N
2010-01-01
The dynamics of a large quantum spin coupled parametrically to an optical resonator is treated in analogy with the motion of a cantilever in cavity optomechanics. New spin optodynamic phenonmena are predicted, such as cavity-spin bistability, optodynamic spin-precession frequency shifts, coherent amplification and damping of spin, and the spin optodynamic squeezing of light.
Mundus, C; Müller-Warmuth, W
1995-10-01
27Al magic-angle spinning nuclear magnetic resonance satellite transition spectroscopy at 78 MHz has been applied to determine (true) chemical shift and quadrupole coupling parameters of glasses in the system K2O-Al2O3-SiO2 with 60-80 mol% SiO2 and K2O concentrations between 0 and 24 mol%. The powdered crystalline aluminosilicates andalusite and sillimanite have also been examined. In the glasses, all Al appears to be tetrahedrally bound in the aluminosilicate network unless x = mol% K2O:mol% Al2O3 becomes extremely small. Upon decreasing x the distortion of the tetrahedral Al(OSi)4 units increases in steps, and possible explanations are discussed. Six-coordinated aluminum observed for x < 0.2 is connected with the occurrence of interstitial Al3+ ions which charge-compensate the AlO4 units in addition to K+. PMID:8748646
Energy Technology Data Exchange (ETDEWEB)
Kamal, Anwar
2014-09-01
Explains the concepts in detail and in depth. Provides step-by-step derivations. Contains numerous tables and diagrams. Supports learning and teaching with numerous worked examples, questions and problems with answers. Sketches also the historical development of the subject. This textbook explains the experimental basics, effects and theory of nuclear physics. It supports learning and teaching with numerous worked examples, questions and problems with answers. Numerous tables and diagrams help to better understand the explanations. A better feeling to the subject of the book is given with sketches about the historical development of nuclear physics. The main topics of this book include the phenomena associated with passage of charged particles and radiation through matter which are related to nuclear resonance fluorescence and the Moessbauer effect., Gamov's theory of alpha decay, Fermi theory of beta decay, electron capture and gamma decay. The discussion of general properties of nuclei covers nuclear sizes and nuclear force, nuclear spin, magnetic dipole moment and electric quadrupole moment. Nuclear instability against various modes of decay and Yukawa theory are explained. Nuclear models such as Fermi Gas Model, Shell Model, Liquid Drop Model, Collective Model and Optical Model are outlined to explain various experimental facts related to nuclear structure. Heavy ion reactions, including nuclear fusion, are explained. Nuclear fission and fusion power production is treated elaborately.
International Nuclear Information System (INIS)
Explains the concepts in detail and in depth. Provides step-by-step derivations. Contains numerous tables and diagrams. Supports learning and teaching with numerous worked examples, questions and problems with answers. Sketches also the historical development of the subject. This textbook explains the experimental basics, effects and theory of nuclear physics. It supports learning and teaching with numerous worked examples, questions and problems with answers. Numerous tables and diagrams help to better understand the explanations. A better feeling to the subject of the book is given with sketches about the historical development of nuclear physics. The main topics of this book include the phenomena associated with passage of charged particles and radiation through matter which are related to nuclear resonance fluorescence and the Moessbauer effect., Gamov's theory of alpha decay, Fermi theory of beta decay, electron capture and gamma decay. The discussion of general properties of nuclei covers nuclear sizes and nuclear force, nuclear spin, magnetic dipole moment and electric quadrupole moment. Nuclear instability against various modes of decay and Yukawa theory are explained. Nuclear models such as Fermi Gas Model, Shell Model, Liquid Drop Model, Collective Model and Optical Model are outlined to explain various experimental facts related to nuclear structure. Heavy ion reactions, including nuclear fusion, are explained. Nuclear fission and fusion power production is treated elaborately.
Electrical control over single hole spins in nanowire quantum dots
Pribiag, V. S.; Nadj-Perge, S.; S.M. Frolov; van den Berg, J. W. G.; van Weperen, I.; Plissard, S.R. (Sebastien) (Postdoc); Bakkers, E.P.A.M. (Erik) (Professor); Kouwenhoven, L.P.
2013-01-01
The development of viable quantum computation devices will require the ability to preserve the coherence of quantum bits (qubits). Single electron spins in semiconductor quantum dots are a versatile platform for quantum information processing, but controlling decoherence remains a considerable challenge. Hole spins in III–V semiconductors have unique properties, such as a strong spin–orbit interaction and weak coupling to nuclear spins, and therefore, have the potential for enhanced spin cont...
Double-spin-flip resonance of rhodium nuclei at positive and negative spin temperatures
DEFF Research Database (Denmark)
Tuoriniemi, J.T.; Knuuttila, T.A.; Lefmann, K.;
2000-01-01
Sensitive SQUID-NMR measurements were used to study the mutual interactions in the highly polarized nuclear-spin system of rhodium metal. The dipolar coupling gives rise to a weak double-spin-flip resonance. The observed frequency shifts allow deducing separately the dipolarlike contribution...
One-Step Implementation of Single Spin Measurement in Spin Star Network
Institute of Scientific and Technical Information of China (English)
DENG Hong-Liang; FANG Xi-Ming
2008-01-01
We present an efficient one-step scheme for a single spin measurement based on nuclear magnetic resonance (NMR)techniques.This scheme considerably reduces the time of operation using a spin star network where a target spin and an ancillary spin are coupled to a ring of N spins.As opposed to the proposal in [Phys.Rev.Lett.97(2006)100501]using a cubic lattice crystal to achieve a cubic speedup,the distinct advantage of this scheme is that under ideal conditions it requires the application of only one step to create a system of N correlated spins.In the process of single spin measurement,the total macroscopic magnetization,the individual magnetization and the transfer fideity are calculated analytically as simple cosine functions of time and the amplitude of irradiation.
16th Workshop on High Energy Spin Physics
2016-01-01
The Workshop will cover a wide range of spin phenomena at high and intermediate energies such as: recent experimental data on spin physics the nucleon spin structure and GPD's spin physics and QCD spin physics in the Standard Model and beyond T-odd spin effects polarization and heavy ion physics spin in gravity and astrophysics the future spin physics facilities spin physics at NICA polarimeters for high energy polarized beams acceleration and storage of polarized beams the new polarization technology related subjects The Workshop will be held in the Bogoliubov Laboratory of Theoretical Physics of the Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia. The program of the workshop will include plenary and parallel (if necessary) sessions. Plenary sessions will be held in the Conference Hall. Parallel sections will take place in the same building. There will be invited talks (up to 40 min) and original reports (20 min). The invited speakers will present new experimental and theoretical re...
Spin noise spectroscopy of ZnO
Energy Technology Data Exchange (ETDEWEB)
Horn, Hauke; Huebner, Jens; Oestreich, Michael [Institute for Solid State Physics, Gottfried Wilhelm Leibniz University Hannover (Germany); Marie, Xavier; Balocchi, Andrea [INSA-CNRS-UPS, LPCNO, Universite de Toulouse (France)
2010-07-01
ZnO is a promising material for optical spintronics showing long electron spin lifetimes due to the large band gap and low amount of nuclear spin isotopes. Here, we use spin noise spectroscopy to access the electron spin dynamics of this material in thermal equilibrium while avoiding carrier heating and excitation of electron hole pairs. A linear polarized laser beam (E{sub UV-Laser}=3.32 eV) close to the direct band gap of ZnO (E{sub D}{sup 0}{sub X}=3.36 eV) is used to detect the spin dynamics of neutral donors in ZnO with off-resonant, non-demolition Faraday rotation. The stochastic oriented electron spins induce polarization fluctuations of the transmitted laser beam. The fluctuation strength of N non-interacting, paramagnetic spins follow the Poisson statistics and generate measurable noise {proportional_to}{radical}(N) spins. These fluctuations are measured via a polarization bridge in the radio frequency regime and Fourier transformed in real-time. A magnetic field B is applied in Voigt-geometry and modulates the noise signal with the Larmor frequency of the electron spins {omega}{sub L}=g{mu}{sub B}B/{Dirac_h}. From the recorded noise spectra we can extract the electron g-factor, spin lifetimes, and densities.
Collective nuclear dynamics. Proceedings
International Nuclear Information System (INIS)
The Fourth International school on nuclear physics was help on 29 Aug - 7 Sep, 1994 in Ukraine. The specialists discussed following subjects:liquid drop and the shell correction method; nuclear deformation energy and fission; nuclear structure at high spins, superdeformed states, structure of excited and exotic nuclei; nuclear fluid dynamics and large scale collective motion; order and chaos as they relate to the collective motion; quantum and interference phenomena in nuclear collisions; quasi-fission and multinucleon fragmentation effects; shell effects in non-nuclear systems; new nuclear facilities
Theory of quantum control of spin-photon dynamics and spin decoherence in semiconductors
Yao, Wang
Single electron spin in a semiconductor quantum dot (QD) and single photon wavepacket propagating in an optical waveguide are investigated as carriers of quantum bit (qubit) for information processing. Cavity quantum electrodynamics of the coupled system composed of charged QD, microcavity and waveguide provides a quantum interface for the interplay of stationary spin qubits and flying photon qubits via cavity assisted optical control. This interface forms the basis for a wide range of essential functions of a quantum network, including transferring, swapping, and entangling qubits at distributed quantum nodes as well as a deterministic source and an efficient detector of a single photon wavepacket with arbitrarily specified shape. The cavity assisted optical process also made possible ultrafast initialization and QND readout of the spin qubit in QD. In addition, the strong optical nonlinearity of dot-cavity-waveguide coupled system enables phase gate and entanglement operation for flying single photon qubits in waveguides. The coherence of the electron spin is the wellspring of these quantum applications being investigated. At low temperature and strong magnetic field, the dominant cause of electron spin decoherence is the coupling with the interacting lattice nuclear spins. We present a quantum solution to the coupled dynamics of the electron with the nuclear spin bath. The decoherence is treated in terms of quantum entanglement of the electron with the nuclear pair-flip excitations driven by the various nuclear interactions. A novel nuclear interaction, mediated by virtue spin-flips of the single electron, plays an important role in single spin free-induction decay (FID). The spin echo not only refocuses the dephasing by inhomogeneous broadening in ensemble dynamics but also eliminates the decoherence by electron-mediated nuclear interaction. Thus, the decoherence times for single spin FID and ensemble spin echo are significantly different. The quantum theory of
Directory of Open Access Journals (Sweden)
Astier Alain
2013-12-01
Full Text Available Two fusion-fission experiments have been performed and studied with the Euroball Ge array: 12C+ 238U at 90 MeV bombarding energy, and 18O + 208Pb at 85 MeV. Among the lot of new information extracted during the last decade, the latest results discussed here are the discovery of the high-spin states of 119–126Sn. The maximum value of angular momentum available in the νh11/2 shell, i.e. for mid-occupation and the breaking of the three neutron pairs (seniority v = 6, has been identified in several tin isotopes. It is the first time that such high-seniority states are established in spherical nuclei.
International Nuclear Information System (INIS)
Two fusion-fission experiments have been performed and studied with the Euroball Ge array: 12C+ 238U at 90 MeV bombarding energy, and 18O + 208Pb at 85 MeV. Among the lot of new information extracted during the last decade, the latest results discussed here are the discovery of the high-spin states of 119-126Sn. The maximum value of angular momentum available in the Vh11/2 shell, i.e. for mid-occupation and the breaking of the three neutron pairs (seniority v = 6), has been identified in several tin isotopes. It is the first time that such high-seniority states are established in spherical nuclei. (authors)
Spin injection into semiconductors
Oestreich, M.; Hübner, J.; Hägele, D.; Klar, P. J.; Heimbrodt, W.; Rühle, W. W.; Ashenford, D. E.; Lunn, B.
1999-03-01
The injection of spin-polarized electrons is presently one of the major challenges in semiconductor spin electronics. We propose and demonstrate a most efficient spin injection using diluted magnetic semiconductors as spin aligners. Time-resolved photoluminescence with a Cd0.98Mn0.02Te/CdTe structure proves the feasibility of the spin-alignment mechanism.
Hyperpolarization in coupled multi-spin systems
Energy Technology Data Exchange (ETDEWEB)
Korchak, Sergey Evgen' evich
2010-06-21
Nuclear magnetic resonance experiments on multi-spin systems using variation of the external magnetic field were performed with high spectral resolution. The main focus was investigating the behaviour of hyperpolarized nuclear spin states in the coupled spin systems in its dependence on the strength of the magnetic field in order to discriminate field dependent effects from others and to optimize the hyperpolarization (HP) yield. All experiments were done on liquid state solutions, thus, the main interaction between the spins was scalar spin-spin coupling, which is not averaged in low viscosity liquids in contrast to dipolar spin-spin interaction. It was possible to separate the paramagnetic effect from the strong coupling effect. Several methods of hyperpolarization were explored: Chemically Induced Dynamic Nuclear Polarization (CIDNP), Parahydrogen Induced Polarization (PHIP), and Dynamic Nuclear Polarization (DNP). Experiments were performed with the aim to manipulate hyperpolarization by control of spin coherences and to exploit the encoded information for analytical purposes. Criteria for the polarization manipulation at variable field were derived and experimentally checked. The DNP experiments were conducted with driving the electronic spins off equilibrium by applying a train of radio-frequency pulses in comparison with cw irradiation. Strong hyperpolarization was obtained in the hydrogenation reaction of styrene with the singlet spin isomer of hydrogen gas (parahydrogen) and studied at variable field. While for the protons originating from parahydrogen the high polarization was observed at all field amplitudes, in low field also polarization of the phenyl ring protons of the product was detected as a result of polarization transfer among strongly coupled spins. CIDNP techniques were applied to amino acids, nucleotides and cycloketones. The most extensive investigation was performed on radical intermediates of the essential amino acid methionine and of
Quadrupolar and anisotropy effects on dephasing in two-electron spin qubits in GaAs
Botzem, Tim; McNeil, Robert P. G.; Mol, Jan-Michael; Schuh, Dieter; Bougeard, Dominique; Bluhm, Hendrik
2016-04-01
Understanding the decoherence of electron spins in semiconductors due to their interaction with nuclear spins is of fundamental interest as they realize the central spin model and of practical importance for using them as qubits. Interesting effects arise from the quadrupolar interaction of nuclear spins with electric field gradients, which have been shown to suppress diffusive nuclear spin dynamics and might thus enhance electron spin coherence. Here we show experimentally that for gate-defined GaAs quantum dots, quadrupolar broadening of the nuclear Larmor precession reduces electron spin coherence by causing faster decorrelation of transverse nuclear fields. However, this effect disappears for appropriate field directions. Furthermore, we observe an additional modulation of coherence attributed to an anisotropic electronic g-tensor. These results complete our understanding of dephasing in gated quantum dots and point to mitigation strategies. They may also help to unravel unexplained behaviour in self-assembled quantum dots and III-V nanowires.
Institute of Scientific and Technical Information of China (English)
ZHANG Peng-Fei; RUAN Tu-Nan
2001-01-01
A systematic theory on the appropriate spin operators for the relativistic states is developed. For a massive relativistic particle with arbitrary nonzero spin, the spin operator should be replaced with the relativistic one, which is called in this paper as moving spin. Further the concept of moving spin is discussed in the quantum field theory. A new is constructed. It is shown that, in virtue of the two operators, problems in quantum field concerned spin can be neatly settled.
Simulations of Information Transport in Spin Chains
Cappellaro, Paola; Ramanathan, Chandrasekhar; Cory, David G.
2007-01-01
Transport of quantum information in linear spin chains has been the subject of much theoretical work. Experimental studies by nuclear spin systems in solid-state by NMR (a natural implementation of such models) is complicated since the dipolar Hamiltonian is not solely comprised of nearest-neighbor XY-Heisenberg couplings. We present here a similarity transformation between the XY-Heisenberg Hamiltonian and the grade raising Hamiltonian, an interaction which is achievable with the collective ...
Single spin stochastic optical reconstruction microscopy
Pfender, Matthias; Waldherr, Gerald; Wrachtrup, Jörg
2014-01-01
We experimentally demonstrate precision addressing of single quantum emitters by combined optical microscopy and spin resonance techniques. To this end we utilize nitrogen-vacancy (NV) color centers in diamond confined within a few ten nanometers as individually resolvable quantum systems. By developing a stochastic optical reconstruction microscopy (STORM) technique for NV centers we are able to simultaneously perform sub diffraction-limit imaging and optically detected spin resonance (ODMR) measurements on NV spins. This allows the assignment of spin resonance spectra to individual NV center locations with nanometer scale resolution and thus further improves spatial discrimination. For example, we resolved formerly indistinguishable emitters by their spectra. Furthermore, ODMR spectra contain metrology information allowing for sub diffraction-limit sensing of, for instance, magnetic or electric fields with inherently parallel data acquisition. As an example, we have detected nuclear spins with nanometer sca...
Spin noise spectroscopy on donors in GaAs
Energy Technology Data Exchange (ETDEWEB)
Bernien, Hannes; Mueller, Georg; Roemer, Michael; Huebner, Jens; Oestreich, Michael [Institute for Solid State Physics, Gottfried Wilhelm Leibniz University Hannover (Germany)
2009-07-01
In recent experiments spin noise spectroscopy (SNS) has proven to be a very sensitive technique to study electron spin dynamics in semiconductors at thermal equilibrium. Here we present SNS-measurements on donor bound electrons in very low doped bulk GaAs. In this environment the donors do not interact with each other and form artificial atoms. We discuss the detection of single donor bound electron spins, which should have extremely long spin relaxation times compared to ensemble spin relaxation times. In further experiments the electron bound to the donor will be used to probe and study the local nuclear magnetic field at the donor site.
Wu, Na; Ding, Wenkui; Shi, Anqi; Zhang, Wenxian
2016-08-01
We investigate the dynamic nuclear polarization in a quantum dot. Due to the suppression of direct dipolar and indirect electron-mediated nuclear spin interactions by frequently injected electron spins, our analytical results under independent spin approximation agree well with quantum numerical simulations for a small number of nuclear spins. We find that the acquired nuclear polarization is highly inhomogeneous, proportional to the square of the local electron-nuclear hyperfine interaction constant. Starting from the inhomogeneously polarized nuclear spins, we further show that the electron polarization decay time can be extended 100 times even at a relatively low nuclear polarization.
Spin diffusion in an inhomogeneous internal field (non equidistant energy spectrum)
Furman, Gregory B.; Goren, Shaul D.
2004-01-01
The theory of spin diffusion is extended to the case of spin lattice relaxation and spin diffusion in an inhomogeneous field in spin systems with non-equidistant energy spectrum. Two coupled equations describing the mutual relaxation and the spin diffusion of the nuclear magnetization and dipolar energy were obtained by using the method of nonequilibrium state operator. The equations were solved for short and long times approximation corresponding to the direct and diffusion relaxation regimes.
Yoshitake, Junki; Nasu, Joji; Motome, Yukitoshi
2016-10-01
Experimental identification of quantum spin liquids remains a challenge, as the pristine nature is to be seen in asymptotically low temperatures. We here theoretically show that the precursor of quantum spin liquids appears in the spin dynamics in the paramagnetic state over a wide temperature range. Using the cluster dynamical mean-field theory and the continuous-time quantum Monte Carlo method, which are newly developed in the Majorana fermion representation, we calculate the dynamical spin structure factor, relaxation rate in nuclear magnetic resonance, and magnetic susceptibility for the honeycomb Kitaev model whose ground state is a canonical example of the quantum spin liquid. We find that dynamical spin correlations show peculiar temperature and frequency dependence even below the temperature where static correlations saturate. The results provide the experimentally accessible symptoms of the fluctuating fractionalized spins evincing the quantum spin liquids.
Constraints on anomalous spin-spin interactions from spin-exchange collisions
Kimball, D F Jackson; Budker, D
2010-01-01
Measured and calculated cross sections for spin-exchange between alkali atoms and noble gases (specifically sodium and helium) are used to constrain anomalous spin-dependent forces between nuclei at the atomic scale ($\\sim 10^{-8}~{\\rm cm}$). Combined with existing stringent limits on anomalous short-range, spin-dependent couplings of the proton, the dimensionless coupling constant for a heretofore undiscovered axial vector interaction of the neutron arising from exchange of a boson of mass $\\lesssim 100~{\\rm eV}$ is constrained to be $g_A^n/\\sqrt{4 \\pi \\hbar c} < 2 \\times 10^{-3}$. Constraints are established for a velocity- and spin-dependent interaction $\\propto \\prn{\\mathbf{I} \\cdot \\mathbf{v}} \\prn{\\mathbf{K} \\cdot \\mathbf{v}}$, where $\\mathbf{I}$ and $\\mathbf{K}$ are the nuclear spins of He and Na, respectively, and $\\mathbf{v}$ is the relative velocity of the atoms. Constraints on torsion gravity are also considered.
International Nuclear Information System (INIS)
A number of cow tooth samples are collected from the adjacent village of Khetolai, located 5 km from the actual Indian Nuclear Test Site in Rajasthan. The samples were processed and utilized for ESR measurements in this study by an X-band spectrometer from JEOL, Japan. The excess dose, determined by subtraction of the natural background dose from the dose absorbed by the enamel was found to the extent of 142 mGy. The intensity of ESR measurement of cow teeth, however, is lower than the human teeth in general. The detailed results obtained on dose estimation in the present study and its correlation with dose exposure for human beings as a result of nuclear test will be presented. The results of this study amply suggest that there is no direct evidence attributing to the development tumors in the cattle population of the locality. There are definitely other factors which were responsible for occurrence of such tumors and other congenital defects in the animal population in the area
Numerical modeling of the central spin problem using the spin coherent states P-representation
Dobrovitski, V. V.; Al-Hassanieh, K. A.; Dagotto, E.; Harmon, B. N.
2006-03-01
We analyze decoherence of a central spin coupled to a spin bath (the central spin problem). Theoretical understanding of this process is important for many experiments, such as the recent study of decoherence of the electron spin by the nuclear spins in a quantum dot. To investigate the important non-perturbative decoherence regimes, we developed an efficient mean-field-based method for modeling the spin-bath decoherence. The method is based on the P-representation for the central spin density matrix, which is very useful in quantum optics, but has not been widely applied to quantum many-spin systems. In contrast with the standard time-dependent mean field theory, our method gives excellent agreement with the exact solution. We demonstrate performance of the method for longitudinal and transversal relaxation at different external fields. In particular, by modeling the quantum systems with up to 16000 bath spins, we make controlled predictions for the slow long-time decoherence of the central spin. We thank L. Glazman, M. Lukin, A. Polkovnikov, and J. Taylor for helpful discussions. This work was supported by NSA, ARDA, ARO, and NSF.
Energy Technology Data Exchange (ETDEWEB)
Kobayashi, Takeshi [Ames Laboratory; Gupta, Shalabh [Ames Laboratory; Caporini, Marc A [Bruker BioSpin Corporation; Pecharsky, Vitalij K [Ames Laboratory; Pruski, Marek [Ames Laboratory
2014-08-28
The solid-state thermolysis of ammonia borane (NH3BH3, AB) was explored using state-of-the-art 15N solid-state NMR spectroscopy, including 2D indirectly detected 1H{15N} heteronuclear correlation and dynamic nuclear polarization (DNP)-enhanced 15N{1H} cross-polarization experiments as well as 11B NMR. The complementary use of 15N and 11B NMR experiments, supported by density functional theory calculations of the chemical shift tensors, provided insights into the dehydrogenation mechanism of AB—insights that have not been available by 11B NMR alone. Specifically, highly branched polyaminoborane derivatives were shown to form from AB via oligomerization in the “head-to-tail” manner, which then transform directly into hexagonal boron nitride analog through the dehydrocyclization reaction, bypassing the formation of polyiminoborane.
Magnetic Nanostructures Spin Dynamics and Spin Transport
Farle, Michael
2013-01-01
Nanomagnetism and spintronics is a rapidly expanding and increasingly important field of research with many applications already on the market and many more to be expected in the near future. This field started in the mid-1980s with the discovery of the GMR effect, recently awarded with the Nobel prize to Albert Fert and Peter Grünberg. The present volume covers the most important and most timely aspects of magnetic heterostructures, including spin torque effects, spin injection, spin transport, spin fluctuations, proximity effects, and electrical control of spin valves. The chapters are written by internationally recognized experts in their respective fields and provide an overview of the latest status.
Wolny, Juliusz A; Rackwitz, Sergej; Achterhold, Klaus; Garcia, Yann; Muffler, Kai; Naik, Anil D; Schünemann, Volker
2010-11-28
The vibrational properties of the trimeric iron complex [Fe(3)(4-(2'-hydroxy-ethyl)-1,2,4-triazole)(6)(H(2)O)(6)](CF(3)SO(3))(6) which serves as a model of the 1D iron coordination polymers based on 1,2,4-triazoles have been investigated by nuclear inelastic scattering of synchrotron radiation (NIS), as well as by Raman and infrared (IR) spectroscopy. The system reveals a soft spin crossover involving only the central iron atom with its FeN(6) core, while the terminal FeN(3)O(3) units show no spin transition. The NIS spectra of the central low-spin isomer exhibit a number of marker bands in the 350-450 cm(-1) region which have not been detected in the Raman spectra. The density functional theory (DFT) calculations allowed the assignment of these bands to Fe-N bending and stretching modes. A characteristic high-spin marker mode has been identified and discriminated from the iron-ligand modes of the terminal iron atoms. This characteristic central Fe-N mode has been observed experimentally at 245 cm(-1) and theoretically at 255 cm(-1). Contrary to mononuclear centrosymmetric Fe complexes, some of the symmetric vibrations of the trimeric complex involving iron movements are observed by NIS. Furthermore the DFT calculations displayed the importance of the coulombic repulsion between metal ions for the geometry and stability of a given spin isomer. PMID:20931141
Nuclear Magnetic Resonance Coupling Constants and Electronic Structure in Molecules.
Venanzi, Thomas J.
1982-01-01
Theory of nuclear magnetic resonance spin-spin coupling constants and nature of the three types of coupling mechanisms contributing to the overall spin-spin coupling constant are reviewed, including carbon-carbon coupling (neither containing a lone pair of electrons) and carbon-nitrogen coupling (one containing a lone pair of electrons).…
Pulsed nuclear-electronic magnetic resonance
Morley, Gavin W; Mohammady, M Hamed; Aeppli, Gabriel; Kay, Christopher W M; Jeschke, Gunnar; Monteiro, Tania S
2011-01-01
Pulsed magnetic resonance is a wide-reaching technology allowing the quantum state of electronic and nuclear spins to be controlled on the timescale of nanoseconds and microseconds respectively. The time required to flip either dilute electronic or nuclear spins is orders of magnitude shorter than their decoherence times, leading to several schemes for quantum information processing with spin qubits. We investigate instead the novel regime where the eigenstates approximate 50:50 superpositions of the electronic and nuclear spin states forming "nuclear-electronic" qubits. Here we demonstrate quantum control of these states, using bismuth-doped silicon, in just 32 ns: orders of magnitude shorter than previous experiments where pure nuclear states were used. The coherence times of our states are over four orders of magnitude longer, being 1 ms or more at 8 K, and are limited by the naturally-occurring 29Si nuclear spin impurities. There is quantitative agreement between our experiments and no-free-parameter anal...
Energy Technology Data Exchange (ETDEWEB)
BAI,M.; ROSER, T.
2007-06-25
This paper proposes a new design of spin flipper for RHIC to obtain full spin flip with the spin tune staying at half integer. The traditional technique of using an rf dipole or solenoid as spin flipper to achieve full spin flip in the presence of full Siberian snake requires one to change the snake configuration to move the spin tune away from half integer. This is not practical for an operational high energy polarized proton collider like RHIC where beam lifetime is sensitive to small betatron tune change. The design of the new spin flipper as well as numerical simulations are presented.
Decoherence dynamics of a single spin versus spin ensemble
Dobrovitski, V.V.; Feiguin, A.E.; Awschalom, D.D.; Hanson, R.
2008-01-01
We study decoherence of central spins by a spin bath, focusing on the difference between measurement of a single central spin and measurement of a large number of central spins (as found in typical spin-resonance experiments). For a dilute spin bath, the single spin demonstrates Gaussian free-induct
Yin, Gen; Liu, Yizhou; Barlas, Yafis; Zang, Jiadong; Lake, Roger K.
2015-01-01
The intrinsic spin Hall effect (SHE) originates from the topology of the Bloch bands in momentum space. The duality between real space and momentum space calls for a spin Hall effect induced from a real space topology in analogy to the topological Hall effect (THE) of skyrmions. We theoretically demonstrate the topological spin Hall effect (TSHE) in which a pure transverse spin current is generated from a skyrmion spin texture.
Murakami, Shuichi
2005-01-01
A brief review is given on the spin Hall effect, where an external electric field induces a transverse spin current. It has been recognized over 30 years that such effect occurs due to impurities in the presence of spin-orbit coupling. Meanwhile, it was proposed recently that there is also an intrinsic contribution for this effect. We explain the mechanism for this intrinsic spin Hall effect. We also discuss recent experimental observations of the spin Hall effect.
Cahaya, Adam B.; Tretiakov, Oleg A.; Bauer, G. E. W.
2015-01-01
Spin caloritronics is the science and technology to control spin, charge, and heat currents in magnetic nanostructures. The spin degree of freedom provides new strategies for thermolelectric power generation that have not yet been fully explored. After an elementary introduction into conventional thermoelectrics and spintronics, we give a brief review of the physics of spin caloritronics. We discuss spin-dependent thermoelectrics based on the the two-current model in metallic magnets as well ...
Spin projection chromatography
Danieli, Ernesto P.; Pastawski, Horacio M.; Levstein, Patricia R.
2003-01-01
We formulate the many-body spin dynamics at high temperature within the non-equilibrium Keldysh formalism. For the simplest XY interaction, analytical expressions in terms of the one particle solutions are obtained for linear and ring configurations. For small rings of even spin number, the group velocities of excitations depend on the parity of the total spin projection. This should enable a dynamical filtering of spin projections with a given parity i.e. a Spin projection chromatography.
Spin projection chromatography
Danieli, E. P.; Pastawski, H. M.; Levstein, P. R.
2004-01-01
We formulate the many-body spin dynamics at high temperature within the non-equilibrium Keldysh formalism. For the simplest XY interaction, analytical expressions in terms of the one particle solutions are obtained for linear and ring configurations. For small rings of even spin number, the group velocities of excitations depend on the parity of the total spin projection. This should enable a dynamical filtering of spin projections with a given parity i.e., a spin projection chromatography.
Spin microscope based on optically detected magnetic resonance
Berman, Gennady P.; Chernobrod, Boris M.
2007-12-11
The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.
Direct detection of spin waves in gaseous 3He↑
Tastevin, G.; Nacher, P.J.; Leduc, M.; Laloë, F.
1985-01-01
In gaseous spin-polarized 3He at low temperature, spin-diffusion becomes oscillatory and gives rise to spin waves; these waves have a quality factor μM, where M is the (relative) nuclear magnetization and μ a dimensionless coefficient characteristic of the importance of exchange effects in binary collisions. We describe here an NMR technique where these oscillatory modes are directly excited and detected, with the use of two sets of radiofrequency coils (for induction and detection), each con...
Hybrid Spin Noise Spectroscopy and the Spin Hall Effect
Slipko, V. A.; Sinitsyn, N. A.; Pershin, Y. V.
2013-01-01
Here we suggest a novel hybrid spin noise spectroscopy technique, which is sensitive to the spin Hall effect. It is shown that, while the standard spin-spin correlation function is not sensitive to the spin Hall effect, spin-transverse voltage and transverse voltage-voltage correlation functions provide the missing sensitivity being linear and quadratic in the spin Hall coefficient, respectively. The correlation between transverse voltage and spin fluctuations appears as a result of spin-char...
Magnons, Spin Current and Spin Seebeck Effect
Maekawa, Sadamichi
2012-02-01
When metals and semiconductors are placed in a temperature gradient, the electric voltage is generated. This mechanism to convert heat into electricity, the so-called Seebeck effect, has attracted much attention recently as the mechanism for utilizing wasted heat energy. [1]. Ferromagnetic insulators are good conductors of spin current, i.e., the flow of electron spins [2]. When they are placed in a temperature gradient, generated are magnons, spin current and the spin voltage [3], i.e., spin accumulation. Once the spin voltage is converted into the electric voltage by inverse spin Hall effect in attached metal films such as Pt, the electric voltage is obtained from heat energy [4-5]. This is called the spin Seebeck effect. Here, we present the linear-response theory of spin Seebeck effect based on the fluctuation-dissipation theorem [6-8] and discuss a variety of the devices. [4pt] [1] S. Maekawa et al, Physics of Transition Metal Oxides (Springer, 2004). [0pt] [2] S. Maekawa: Nature Materials 8, 777 (2009). [0pt] [3] Concept in Spin Electronics, eds. S. Maekawa (Oxford University Press, 2006). [0pt] [4] K. Uchida et al., Nature 455, 778 (2008). [0pt] [5] K. Uchida et al., Nature Materials 9, 894 (2010) [0pt] [6] H. Adachi et al., APL 97, 252506 (2010) and Phys. Rev. B 83, 094410 (2011). [0pt] [7] J. Ohe et al., Phys. Rev. B (2011) [0pt] [8] K. Uchida et al., Appl. Phys. Lett. 97, 104419 (2010).
Spin-polarized spin excitation spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Loth, Sebastian; Lutz, Christopher P; Heinrich, Andreas J, E-mail: lothseb@us.ibm.com, E-mail: heinrich@almaden.ibm.com [IBM Research Division, Almaden Research Center, San Jose, CA 95120 (United States)
2010-12-15
We report on the spin dependence of elastic and inelastic electron tunneling through transition metal atoms. Mn, Fe and Cu atoms were deposited onto a monolayer of Cu{sub 2}N on Cu(100) and individually addressed with the probe tip of a scanning tunneling microscope. Electrons tunneling between the tip and the substrate exchange energy and spin angular momentum with the surface-bound magnetic atoms. The conservation of energy during the tunneling process results in a distinct onset threshold voltage above which the tunneling electrons create spin excitations in the Mn and Fe atoms. Here we show that the additional conservation of spin angular momentum leads to different cross-sections for spin excitations depending on the relative alignment of the surface spin and the spin of the tunneling electron. For this purpose, we developed a technique for measuring the same local spin with a spin-polarized and a non-spin-polarized tip by exchanging the last apex atom of the probe tip between different transition metal atoms. We derive a quantitative model describing the observed excitation cross-sections on the basis of an exchange scattering process.
Entangled spins and ghost-spins
Jatkar, Dileep P
2016-01-01
We study patterns of quantum entanglement in systems of spins and ghost-spins regarding them as simple quantum mechanical toy models for theories containing negative norm states. We define a single ghost-spin as in arXiv:1602.06505 [hep-th] as a 2-state spin variable with an indefinite inner product in the state space. We find that whenever the spin sector is disentangled from the ghost-spin sector (both of which could be entangled within themselves), the reduced density matrix obtained by tracing over all the ghost-spins gives rise to positive entanglement entropy for positive norm states, while negative norm states have an entanglement entropy with a negative real part and a constant imaginary part. However when the spins are entangled with the ghost-spins, there are new entanglement patterns in general. For systems where the number of ghost-spins is even, it is possible to find subsectors of the Hilbert space where positive norm states always lead to positive entanglement entropy after tracing over the gho...
Polarization and readout of coupled single spins in diamond
Hanson, R; Epstein, R J; Awschalom, D D
2006-01-01
We study the coupling of a single nitrogen-vacancy center in diamond to a nearby single nitrogen defect at room temperature. The magnetic dipolar coupling leads to a splitting in the electron spin resonance frequency of the N-V center, allowing readout of the state of a single nitrogen electron spin. At magnetic fields where the spin splitting of the two centers is the same we observe a strong polarization of the nitrogen electron spin. The amount of polarization can be controlled by the optical excitation power. We combine the polarization and the readout in time-resolved pump-probe measurements to determine the spin relaxation time of a single nitrogen electron spin. Finally, we discuss indications for hyperfine-induced polarization of the nitrogen nuclear spin.
Algorithmic Cooling of Spins: A Practicable Method for Increasing Polarization
Fernández, J M; Mor, T; Roychowdhury, V P; Fernandez, Jose M.; Lloyd, Seth; Mor, Tal; Roychowdhury, Vwani
2004-01-01
An efficient technique to generate ensembles of spins that are highly polarized by external magnetic fields is the Holy Grail in Nuclear Magnetic Resonance (NMR) spectroscopy. Since spin-half nuclei have steady-state polarization biases that increase inversely with temperature, spins exhibiting high polarization biases are considered cool, even when their environment is warm. Existing spin-cooling techniques are highly limited in their efficiency and usefulness. Algorithmic cooling is a promising new spin-cooling approach that employs data compression methods in open systems. It reduces the entropy of spins on long molecules to a point far beyond Shannon's bound on reversible entropy manipulations (an information-theoretic version of the 2nd Law of Thermodynamics), thus increasing their polarization. Here we present an efficient and experimentally feasible algorithmic cooling technique that cools spins to very low temperatures even on short molecules. This practicable algorithmic cooling could lead to breakth...
SD-CAS: Spin Dynamics by Computer Algebra System.
Filip, Xenia; Filip, Claudiu
2010-11-01
A computer algebra tool for describing the Liouville-space quantum evolution of nuclear 1/2-spins is introduced and implemented within a computational framework named Spin Dynamics by Computer Algebra System (SD-CAS). A distinctive feature compared with numerical and previous computer algebra approaches to solving spin dynamics problems results from the fact that no matrix representation for spin operators is used in SD-CAS, which determines a full symbolic character to the performed computations. Spin correlations are stored in SD-CAS as four-entry nested lists of which size increases linearly with the number of spins into the system and are easily mapped into analytical expressions in terms of spin operator products. For the so defined SD-CAS spin correlations a set of specialized functions and procedures is introduced that are essential for implementing basic spin algebra operations, such as the spin operator products, commutators, and scalar products. They provide results in an abstract algebraic form: specific procedures to quantitatively evaluate such symbolic expressions with respect to the involved spin interaction parameters and experimental conditions are also discussed. Although the main focus in the present work is on laying the foundation for spin dynamics symbolic computation in NMR based on a non-matrix formalism, practical aspects are also considered throughout the theoretical development process. In particular, specific SD-CAS routines have been implemented using the YACAS computer algebra package (http://yacas.sourceforge.net), and their functionality was demonstrated on a few illustrative examples.
Morawetz, K.
2015-12-01
The coupled kinetic equation for density and spin Wigner functions is derived including spin-orbit coupling, electric and magnetic fields, and self-consistent Hartree mean fields suited for SU(2) transport. The interactions are assumed to be with scalar and magnetic impurities as well as scalar and spin-flip potentials among the particles. The spin-orbit interaction is used in a form suitable for solid state physics with Rashba or Dresselhaus coupling, graphene, extrinsic spin-orbit coupling, and effective nuclear matter coupling. The deficiencies of the two-fluid model are worked out consisting of the appearance of an effective in-medium spin precession. The stationary solution of all these systems shows a band splitting controlled by an effective medium-dependent Zeeman field. The self-consistent precession direction is discussed and a cancellation of linear spin-orbit coupling at zero temperature is reported. The precession of spin around this effective direction caused by spin-orbit coupling leads to anomalous charge and spin currents in an electric field. Anomalous Hall conductivity is shown to consist of the known results obtained from the Kubo formula or Berry phases and a symmetric part interpreted as an inverse Hall effect. Analogously the spin-Hall and inverse spin-Hall effects of spin currents are discussed which are present even without magnetic fields showing a spin accumulation triggered by currents. The analytical dynamical expressions for zero temperature are derived and discussed in dependence on the magnetic field and effective magnetizations. The anomalous Hall and spin-Hall effect changes sign at higher than a critical frequency dependent on the relaxation time.
Gomes, M; da Silva, A J
2010-01-01
Using the Berezin-Marinov pseudoclassical formulation of spin particle we propose a classical model of spin noncommutativity. In the nonrelativistic case, the Poisson brackets between the coordinates are proportional to the spin angular momentum. The quantization of the model leads to the noncommutativity with mixed spacial and spin degrees of freedom. A modified Pauli equation, describing a spin half particle in an external e.m. field is obtained. We show that nonlocality caused by the spin noncommutativity depends on the spin of the particle; for spin zero, nonlocality does not appear, for spin half, $\\Delta x\\Delta y\\geq\\theta^{2}/2$, etc. In the relativistic case the noncommutative Dirac equation was derived. For that we introduce a new star product. The advantage of our model is that in spite of the presence of noncommutativity and nonlocality, it is Lorentz invariant. Also, in the quasiclassical approximation it gives noncommutativity with a nilpotent parameter.
Gomes, M.; Kupriyanov, V. G.; da Silva, A. J.
2010-04-01
Using the Berezin-Marinov pseudoclassical formulation of the spin particle we propose a classical model of spin noncommutativity. In the nonrelativistic case, the Poisson brackets between the coordinates are proportional to the spin angular momentum. The quantization of the model leads to the noncommutativity with mixed spatial and spin degrees of freedom. A modified Pauli equation, describing a spin half particle in an external electromagnetic field is obtained. We show that nonlocality caused by the spin noncommutativity depends on the spin of the particle; for spin zero, nonlocality does not appear, for spin half, ΔxΔy≥θ2/2, etc. In the relativistic case the noncommutative Dirac equation was derived. For that we introduce a new star product. The advantage of our model is that in spite of the presence of noncommutativity and nonlocality, it is Lorentz invariant. Also, in the quasiclassical approximation it gives noncommutativity with a nilpotent parameter.
International Nuclear Information System (INIS)
Using the Berezin-Marinov pseudoclassical formulation of the spin particle we propose a classical model of spin noncommutativity. In the nonrelativistic case, the Poisson brackets between the coordinates are proportional to the spin angular momentum. The quantization of the model leads to the noncommutativity with mixed spatial and spin degrees of freedom. A modified Pauli equation, describing a spin half particle in an external electromagnetic field is obtained. We show that nonlocality caused by the spin noncommutativity depends on the spin of the particle; for spin zero, nonlocality does not appear, for spin half, ΔxΔy≥θ2/2, etc. In the relativistic case the noncommutative Dirac equation was derived. For that we introduce a new star product. The advantage of our model is that in spite of the presence of noncommutativity and nonlocality, it is Lorentz invariant. Also, in the quasiclassical approximation it gives noncommutativity with a nilpotent parameter.
Spin Rotation of Formalism for Spin Tracking
Energy Technology Data Exchange (ETDEWEB)
Luccio,A.
2008-02-01
The problem of which coefficients are adequate to correctly represent the spin rotation in vector spin tracking for polarized proton and deuteron beams in synchrotrons is here re-examined in the light of recent discussions. The main aim of this note is to show where some previous erroneous results originated and how to code spin rotation in a tracking code. Some analysis of a recent experiment is presented that confirm the correctness of the assumptions.
Selected topics in nuclear structure
International Nuclear Information System (INIS)
19. winter school in Zakopane was devoted to selected topics in nuclear structure such as: production of spin resonances, heavy ions reactions and their applications to the investigation of high spin states, octupole deformations, excited states and production of new elements etc. The experimental data are ofen compared with theoretical predictions. Report contains 28 papers. (M.F.W.)
JONGMAN, [No Value; BACELAR, JCS; BALANDA, A; NOORMAN, RF; STEENBERGEN, T; DEVOIGT, MJA; NYBERG, J; SLETTEN, G; DIONISIO, J; VIEU, C; LAGRANGE, JM; PAUTRAT, M; Urban, W
1995-01-01
High-spin states in the odd-odd nucleus Eu-148, populated by a carbon-13 induced reaction on a lanthanum target, were investigated with several different tools of in-beam nuclear spectroscopy. The low-energy levels show collective excitations, interpreted as 3- octupole-phonon couplings to multi-par
Technologic spin-off from CNEA's activities
International Nuclear Information System (INIS)
An analysis is made of the spin-off of technology from the nuclear activities in Argentina. Several examples are mentioned in fields such as material sciences, non-destructive testing, forensic research, space activities, instrumentation as well as in environmental studies
Spin Transport by Collective Spin Excitations
Hammel, P. Chris
We report studies of angular momentum transport in insulating materials. Our measurements reveal efficient spin pumping from high wavevector k spin waves in thin film Y3Fe5O12 (YIG): spin pumping is independent of wavevector up to k ~ 20 μm-1. Optical detection of YIG FMR by NV centers in diamond reveals a role for spin waves in this insulator-to-insulator spin transfer process. Spin transport is typically suppressed by insulating barriers, but we find that fluctuating antiferromagnetic correlations enable efficient spin transport at nm-scale thicknesses in insulating antiferromagnets, even in the absence of long-range order, and that the spin decay length increases with the strength of the antiferromagnetic correlations. This research is supported by the U.S. DOE through Grants DE-FG02-03ER46054 and DE-SC0001304, by the NSF MRSEC program through Grant No. 1420451 and by the Army Research Office through Grant W911NF0910147.
Arbitrary Spin Galilean Oscillator
Hagen, C R
2014-01-01
The so-called Dirac oscillator was proposed as a modification of the free Dirac equation which reproduces many of the properties of the simple harmonic oscillator but accompanied by a strong spin-orbit coupling term. It has yet to be extended successfully to the arbitrary spin S case primarily because of the unwieldiness of general spin Lorentz invariant wave equations. It is shown here using the formalism of totally symmetric multispinors that the Dirac oscillator can, however, be made to accommodate spin by incorporating it into the framework of Galilean relativity. This is done explicitly for spin zero and spin one as special cases of the arbitrary spin result. For the general case it is shown that the coefficient of the spin-orbit term has a 1/S behavior by techniques which are virtually identical to those employed in the derivation of the g-factor carried out over four decades ago.
Schliemann, John
2006-01-01
It is proposed that when a charge current circulates in a paramagnetic metal a transverse spin imbalance will be generated, giving rise to a 'spin Hall voltage'. Similarly, that when a spin current circulates a transverse charge imbalance will be generated, hence a Hall voltage, in the absence of charge current and magnetic field. Based on these principles we propose an experiment to generate and detect a spin current in a paramagnetic metal.
International Nuclear Information System (INIS)
Spin is a beautiful concept that plays an ever important role in modern physics. In this talk, I start with a discussion of the origin of spin, and then turn to three themes in which spin has been crucial in subatomic physics: a lab to explore physics beyond the standard model, a tool to measure physical observables that are hard to obtain otherwise, a probe to unravel nonperturbative QCD. I conclude with some remarks on a world without spin
Nuclear effects in atomic transitions
Pálffy, Adriana
2011-01-01
Atomic electrons are sensitive to the properties of the nucleus they are bound to, such as nuclear mass, charge distribution, spin, magnetization distribution, or even excited level scheme. These nuclear parameters are reflected in the atomic transition energies. A very precise determination of atomic spectra may thus reveal information about the nucleus, otherwise hardly accessible via nuclear physics experiments. This work reviews theoretical and experimental aspects of the nuclear effects ...
DEFF Research Database (Denmark)
Annila, A.J.; Clausen, K.N.; Lindgård, P-A.;
1990-01-01
A new ordering vector k=(2π/a)(0, 2/3, 2/3) for fcc antiferromagnets has been found by neutron-diffraction experiments at nanokelvin temperatures in the nuclear-spin system of a 65Cu single crystal. The corresponding reflection together with the previously observed (100) Bragg peak show the prese......A new ordering vector k=(2π/a)(0, 2/3, 2/3) for fcc antiferromagnets has been found by neutron-diffraction experiments at nanokelvin temperatures in the nuclear-spin system of a 65Cu single crystal. The corresponding reflection together with the previously observed (100) Bragg peak show...
DEFF Research Database (Denmark)
Annila, A.J.; Clausen, K.N.; Lindgård, P.-A.;
1990-01-01
The new antiferromagnetic reflection (02/32/3) has been found by neutron diffraction experiments at nanokelvin temperatures in the nuclear spin system of a 65CU single crystal. The corresponding three-sublattice structure has not been observed previously in any fcc antiferromagnet.......The new antiferromagnetic reflection (02/32/3) has been found by neutron diffraction experiments at nanokelvin temperatures in the nuclear spin system of a 65CU single crystal. The corresponding three-sublattice structure has not been observed previously in any fcc antiferromagnet....
Energy Technology Data Exchange (ETDEWEB)
Kiryutin, Alexey S.; Yurkovskaya, Alexandra V.; Lukzen, Nikita N.; Ivanov, Konstantin L., E-mail: ivanov@tomo.nsc.ru [International Tomography Center SB RAS, Institutskaya 3a, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova 2, Novosibirsk 630090 (Russian Federation); Vieth, Hans-Martin [International Tomography Center SB RAS, Institutskaya 3a, Novosibirsk 630090 (Russian Federation); Freie Universität Berlin, Arnimallee 14, Berlin 14195 (Germany)
2015-12-21
A method for precise manipulation of non-thermal nuclear spin polarization by switching a RF-field is presented. The method harnesses adiabatic correlation of spin states in the rotating frame. A detailed theory behind the technique is outlined; examples of two-spin and three-spin systems prepared in a non-equilibrium state by Para-Hydrogen Induced Polarization (PHIP) are considered. We demonstrate that the method is suitable for converting the initial multiplet polarization of spins into net polarization: compensation of positive and negative lines in nuclear magnetic resonance spectra, which is detrimental when the spectral resolution is low, is avoided. Such a conversion is performed for real two-spin and three-spin systems polarized by means of PHIP. Potential applications of the presented technique are discussed for manipulating PHIP and its recent modification termed signal amplification by reversible exchange as well as for preparing and observing long-lived spin states.
Cross, Rod
2013-01-01
Measurements are presented on the rise of a spinning egg. It was found that the spin, the angular momentum and the kinetic energy all decrease as the egg rises, unlike the case of a ballerina who can increase her spin and kinetic energy by reducing her moment of inertia. The observed effects can be explained, in part, in terms of rolling friction…
Meißner, Ulf-G.
2010-01-01
I review recent developments in theoretical spin physics. Topics include pion production in nucleon-nucleon collisions, the implications of heavy quark spin symmetry for heavy hadron molecules, the nucleon electric dipole form factors and ab initio calculations of the width of hadron resonances. A few spin physics high-lights from experiments at the COSY accelerator are also discussed.
Bauer, G.E.W.; Brataas, A.; Tserkovnyak, Y.; Van Wees, B.J.
2003-01-01
A magnetoelectronic thin-film transistor is proposed that can display negative differential resistance and gain. The working principle is the modulation of the soure–drain current in a spin valve by the magnetization of a third electrode, which is rotated by the spin-torque created by a control spin
Towards a spin radar with Nitrogen Vacancy centers in diamond
Ajoy, Ashok; Liu, Yixiang; Cappellaro, Paola
2016-05-01
Nitrogen Vacancy (NV) centers in diamond are a promising platform for nanoscale magnetic resonance imaging. The NV spin can be used to sense the presence of external nuclear spins, and through them biomolecule structure, by exploiting anisotropic hyperfine interactions. The NV center thus effectively acts as a dipole ``antenna'', detecting and identifying spins at different spatial locations. The antenna dipole is typically set by the diamond and target sample geometry, and nuclear spins are often found in the NV's dipole blind spot. In this work, we demonstrate an experimental technique by which one can controllably turn and manipulate the direction of this effective NV antenna over a wide range of approximately +-40 degrees. In combination with filtered back projection techniques, this method allows reconstructing with high resolution the real space position of spins in the NV center environment.
Hole Spin Relaxation in Ge/Si Core-Shell Nanowire Qubits
DEFF Research Database (Denmark)
Hu, Yongjie; Kuemmeth, Ferdinand; Lieber, Charles;
2011-01-01
qubits in a nuclear-spin-free system, intensive studies based on group-IV semiconductor are being pursued. In this case, the challenge is primarily control of materials and interfaces, and device nanofabrication. We report important steps toward implementing spin qubits in a predominantly nuclear...
A new spin-oriented nuclei facility: POLAREX
International Nuclear Information System (INIS)
Using the On-Line Nuclear Orientation method, POLAREX (Polarization of Exotic nuclei) is a new facility allowing to study the anisotropic decay of spin-oriented nuclei. Based on the combination of on-line implantation of radioactive nuclei with Low Temperature Nuclear Orientation technique and Nuclear Magnetic Resonance, POLAREX allows the measurement of nuclear electromagnetic moments and ground-state spins, in the aim to get information about the wave function composition of the nuclear state. Polarized nuclei can also be used to study fundamental interactions involving nuclear β-decay asymmetries. The POLAREX infrastructure will be installed at the linear accelerator in Orsay in order to study neutron-rich nuclei, some of which have not been studied yet. Will be presented here, all the possibilities of this new facility and a non exhaustive scientific program. The first experiment will be the nuclear magnetic moment measurement of 125Sb as final commissioning
Universal Synchronous Spin Rotators for Electron-Ion Colliders
Chevtsov, Pavel; Krafft, Geoff; Zhang, Yuhong
2016-01-01
The paper provides mathematics and physics considerations concerning a special class of electron spin manipulating structures for future Electron-Ion Collider (EIC) projects. These structures, which we call Universal Synchronous Spin Rotators (USSR), consist of a sequence of standard basic spin manipulating elements or cells built with two solenoids and one bending magnet between them. When integrated into the ring arcs, USSR structures do not affect the central particle orbit, and their spin transformation functions can be described by a linear mathematical model. In spite of being relatively simple, the model allows one to design spin rotators, which are able to perform spin direction changes from vertical to longitudinal and vice versa in significant continuous intervals of the electron energy. This makes USSR especially valuable tools for EIC nuclear physics experiments.
Probing mixed-spin pairing in heavy nuclei
Bulthuis, Brendan
2016-01-01
The nature of the nuclear pairing condensate is an active topic of investigation, especially as regards its neutron-proton versus identical-particle character, which manifests as the difference between spin-singlet and spin-triplet pairing. In this work, we probe the recently proposed mixed-spin pairing condensates, using a phenomenological Hamiltonian and Hartree-Fock-Bogoliubov theory along with the gradient method. In addition to improving the solution of the many-body problem, we have calculated a series of physical quantities and examined the robustness of the mixed-spin pairing state as the input Hamiltonian is modified. Overall, we find that even though the mixed-spin correlation energy is suppressed in comparison to earlier work, the new pairing behavior persists. We also discuss the possibility of directly probing the mixed-spin pairing phase.
Inverse spin Hall effect by spin injection
Liu, S. Y.; Horing, Norman J. M.; Lei, X. L.
2007-09-01
Motivated by a recent experiment [S. O. Valenzuela and M. Tinkham, Nature (London) 442, 176 (2006)], the authors present a quantitative microscopic theory to investigate the inverse spin-Hall effect with spin injection into aluminum considering both intrinsic and extrinsic spin-orbit couplings using the orthogonalized-plane-wave method. Their theoretical results are in good agreement with the experimental data. It is also clear that the magnitude of the anomalous Hall resistivity is mainly due to contributions from extrinsic skew scattering.
Spin supplementary conditions for spinning compact binaries
Mikóczi, Balázs
2016-01-01
We consider the different spin supplementary conditions (SSC) for a spinning compact binary with the leading-order spin-orbit (SO) interaction. The Lagrangian of the binary system can be constructed but it is acceleration-dependent in two cases of SSC. We rewrite the generalized Hamiltonian formalism proposed by Ostrogradsky and compute the conservative quantities and the dissipative part of relative motion during the gravitational radiation of each SSCs. We give the orbital elements and observed quantities of the SO dynamics, for instance the energy and the orbital angular momentum losses and waveforms and discuss their SSC dependence.
Optical pumping of a single hole spin in a quantum dot
Gerardot, Brian D.; Brunner, Daniel; Dalgarno, Paul A.; Öhberg, Patrik; Seidl, Stefan; Kroner, Martin; Karrai, Khaled; Stoltz, Nick G.; Petroff, Pierre M.; Warburton, Richard J.
2008-01-01
The spin of an electron is a natural two-level system for realizing a quantum bit in the solid state. For an electron trapped in a semiconductor quantum dot, strong quantum confinement highly suppresses the detrimental effect of phonon-related spin relaxation. However, this advantage is offset by the hyperfine interaction between the electron spin and the 104 to 106 spins of the host nuclei in the quantum dot. Random fluctuations in the nuclear spin ensemble lead to fast spin decoherence in about ten nanoseconds. Spin-echo techniques have been used to mitigate the hyperfine interaction, but completely cancelling the effect is more attractive. In principle, polarizing all the nuclear spins can achieve this but is very difficult to realize in practice. Exploring materials with zero-spin nuclei is another option, and carbon nanotubes, graphene quantum dots and silicon have been proposed. An alternative is to use a semiconductor hole. Unlike an electron, a valence hole in a quantum dot has an atomic p orbital which conveniently goes to zero at the location of all the nuclei, massively suppressing the interaction with the nuclear spins. Furthermore, in a quantum dot with strong strain and strong quantization, the heavy hole with spin-3/2 behaves as a spin-1/2 system and spin decoherence mechanisms are weak. We demonstrate here high fidelity (about 99 per cent) initialization of a single hole spin confined to a self-assembled quantum dot by optical pumping. Our scheme works even at zero magnetic field, demonstrating a negligible hole spin hyperfine interaction. We determine a hole spin relaxation time at low field of about one millisecond. These results suggest a route to the realization of solid-state quantum networks that can intra-convert the spin state with the polarization of a photon.
Lisovaya E. V.; Victorova E. P.; Agafonov O. S.; Kornen N. N.; Shahray T. A.
2015-01-01
The article presents a comparative assessment and peculiarities of nuclear magnetic relaxation characteristics of rapeseed and sunflower lecithin. It was established, that lecithin’s nuclear magnetic relaxation characteristics, namely, protons’ spin-spin relaxation time and amplitudes of nuclear magnetic relaxation signals of lecithin components, depend on content of oil’s fat acids and phospholipids, contained in the lecithin. Comparative assessment of protons’ spin-spin relaxation time of r...
Mellado, Paula
Spin ice in magnetic pyrochlore oxides is a peculiar magnetic state. Like ordinary water ice, these materials are in apparent violation with the third law of thermodynamics, which dictates that the entropy of a system in thermal equilibrium vanishes as its temperature approaches absolute zero. In ice, a "zero-point" entropy is retained down to low temperatures thanks to a high number of low-energy positions of hydrogen ions associated with the Bernal-Fowler ice-rules. Spins in pyrochlore oxides Ho2Ti 2O7 and Dy2Ti2O7 exhibit a similar degeneracy of ground states and thus also have a sizable zero-point entropy. A recent discovery of excitations carrying magnetic charges in pyrochlore spin ice adds another interesting dimension to these magnets. This thesis is devoted to a theoretical study of a two-dimensional version of spin ice whose spins reside on kagome, a lattice of corner-sharing triangles. It covers two aspects of this frustrated classical spin system: the dynamics of artificial spin ice in a network of magnetic nanowires and the thermodynamics of crystalline spin ice. Magnetization dynamics in artificial spin ice is mediated by the emission, propagation and absorption of domain walls in magnetic nanowires. The dynamics shows signs of self-organized behavior such as avalanches. The theoretical model compares favorably to recent experiments. The thermodynamics of the microscopic version of spin ice on kagome is examined through analytical calculations and numerical simulations. The results show that, in addition to the high-temperature paramagnetic phase and the low-temperature phase with magnetic order, spin ice on kagome may have an intermediate phase with fluctuating spins and ordered magnetic charges. This work is concluded with a calculation of the entropy of kagome spin ice at zero temperature when one of the sublattices is pinned by an applied magnetic field and the system breaks up into independent spin chains, a case of dimensional reduction.
International Nuclear Information System (INIS)
Individual nuclear spins in diamond can be optically detected through hyperfine couplings with the electron spin of a single nitrogen-vacancy (NV) center; such nuclear spins have outstandingly long coherence times. Among the hyperfine couplings in the NV center, the nearest neighbor 13C nuclear spins have the largest coupling strength. Nearest neighbor 13C nuclear spins have the potential to perform fastest gate operations, providing highest fidelity in quantum computing. Herein, we report on the control of coherences in the NV center where all three nearest neighbor carbons are of the 13C isotope. Coherence among the three and four qubits are generated and analyzed at room temperature
Energy Technology Data Exchange (ETDEWEB)
Shimo-Oka, T.; Miwa, S.; Suzuki, Y.; Mizuochi, N., E-mail: mizuochi@mp.es.osaka-u.ac.jp [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Kato, H.; Yamasaki, S. [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan); Jelezko, F. [Institut für Quantenoptik, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm (Germany)
2015-04-13
Individual nuclear spins in diamond can be optically detected through hyperfine couplings with the electron spin of a single nitrogen-vacancy (NV) center; such nuclear spins have outstandingly long coherence times. Among the hyperfine couplings in the NV center, the nearest neighbor {sup 13}C nuclear spins have the largest coupling strength. Nearest neighbor {sup 13}C nuclear spins have the potential to perform fastest gate operations, providing highest fidelity in quantum computing. Herein, we report on the control of coherences in the NV center where all three nearest neighbor carbons are of the {sup 13}C isotope. Coherence among the three and four qubits are generated and analyzed at room temperature.
NMR with generalized dynamics of spin and spatial coordinates
Energy Technology Data Exchange (ETDEWEB)
Lee, Chang Jae
1987-11-01
This work is concerned with theoretical and experimental aspects of the generalized dynamics of nuclear spin and spatial coordinates under magnetic-field pulses and mechanical motions. The main text begins with an introduction to the concept of ''fictitious'' interactions. A systematic method for constructing fictitious spin-1/2 operators is given. The interaction of spins with a quantized-field is described. The concept of the fictitious interactions under the irradiation of multiple pulses is utilized to design sequences for selectively averaging linear and bilinear operators. Relations between the low-field sequences and high-field iterative schemes are clarified. These relations and the transformation properties of the spin operators are exploited to develop schemes for heteronuclear decoupling of multi-level systems. The resulting schemes are evaluated for heteronuclear decoupling of a dilute spin-1/2 from a spin-1 in liquid crystal samples and from a homonuclear spin-1/2 pair in liquids. A relation between the spin and the spatial variables is discussed. The transformation properties of the spin operators are applied to spatial coordinates and utilized to develop methods for removing the orientational dependence responsible for line broadening in a powder sample. Elimination of the second order quadrupole effects, as well as the first order anisotropies is discussed. It is shown that various sources of line broadening can effectively be eliminated by spinning and/or hopping the sample about judiciously chosen axes along with appropriate radio-frequency pulse sequences.
NMR with generalized dynamics of spin and spatial coordinates
International Nuclear Information System (INIS)
This work is concerned with theoretical and experimental aspects of the generalized dynamics of nuclear spin and spatial coordinates under magnetic-field pulses and mechanical motions. The main text begins with an introduction to the concept of ''fictitious'' interactions. A systematic method for constructing fictitious spin-1/2 operators is given. The interaction of spins with a quantized-field is described. The concept of the fictitious interactions under the irradiation of multiple pulses is utilized to design sequences for selectively averaging linear and bilinear operators. Relations between the low-field sequences and high-field iterative schemes are clarified. These relations and the transformation properties of the spin operators are exploited to develop schemes for heteronuclear decoupling of multi-level systems. The resulting schemes are evaluated for heteronuclear decoupling of a dilute spin-1/2 from a spin-1 in liquid crystal samples and from a homonuclear spin-1/2 pair in liquids. A relation between the spin and the spatial variables is discussed. The transformation properties of the spin operators are applied to spatial coordinates and utilized to develop methods for removing the orientational dependence responsible for line broadening in a powder sample. Elimination of the second order quadrupole effects, as well as the first order anisotropies is discussed. It is shown that various sources of line broadening can effectively be eliminated by spinning and/or hopping the sample about judiciously chosen axes along with appropriate radio-frequency pulse sequences
Muon spin relaxation in random spin systems
International Nuclear Information System (INIS)
The longitudinal relaxation function Gsub(z)(t) of the positive muon can reflect dynamical characters of local field in a unique way even when the correlation time is longer than the Larmor period of local field. This method has been applied to studies of spin dynamics in spin glass systems, revealing sharp but continuous temperature dependence of the correlation time. Its principle and applications are reviewed. (author)
Proceedings of the conference on nuclear structure at the limits
International Nuclear Information System (INIS)
This report contains the papers from the Proceedings of the Conference on Nuclear Structure at the Limits. Some of the areas covered by these papers are: nuclear deformation; nuclear decay; nuclear spectroscopy; radioactive ion beams; nuclear models; high spin states; and heavy ion reactions. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database
Mg spin affects adenosinetriphosphate activity
Tulub, Alexander A
2009-01-01
The Schlegel-Frisch ab initio molecular dynamics (ADMP) (DFT:B3LYP), T = 310 K, is used to study complexation between adenosinetriphosphate (ATP), ATP subsystem, and magnesium cofactor [Mg(H2O)6]2+, Mg subsystem, in a water pool, modeled with 78 water molecules, in singlet (S) and triplet (T) states. The computations prove that the way of ATP cleavage is governed by the electron spin of Mg. In the S state Mg prefers chelation of \\gamma-\\beta-phosphate oxygens (O1-O2), whereas in the T state it chelates \\beta-\\alpha-phosphate oxygens (O2-O3) or produces a single-bonded intermediate. Unlike the chelates, which initiate ionic reaction paths, the single-bonded intermediate starts off a free-radical path of ATP cleavage, yielding a highly reactive adenosinemonophosphate ion-radical, .AMP-, earlier observed in the CIDNP (Chemically Induced Dynamic Nuclear Polarization) experiment (A.A. Tulub, 2006). The free-radical path is highly sensitive to Mg nuclear spin, which through a hyperfine interaction favors the produc...
Spin accumulation in the extrinsic spin Hall effect
Tse, Wang-Kong; Fabian, J.; Žutić, I.; Das Sarma, S.
2005-12-01
The drift-diffusion formalism for spin-polarized carrier transport in semiconductors is generalized to include spin-orbit coupling. The theory is applied to treat the extrinsic spin Hall effect using realistic boundary conditions. It is shown that carrier and spin-diffusion lengths are modified by the presence of spin-orbit coupling and that spin accumulation due to the extrinsic spin Hall effect is strongly and qualitatively influenced by boundary conditions. Analytical formulas for the spin-dependent carrier recombination rates and inhomogeneous spin densities and currents are presented.
Fidelity of spin ensemble memory for mesoscopic quantum bits
Dobrovitski, V. V.; Taylor, J. M.
2005-03-01
Development of techniques for coherently manipulating electron spins in quantum dots is important for future applications in spintronics and in quantum information processing. In this work we study the quantum memory protocol suggested recently [1] for storage and retrieval of the electron spin states in the lattice nuclear spins. We report detailed studies of this technique in the presence of imperfections, such as the incomplete polarization of the nuclear spins and the spread in the hyperfine couplings between the electron and the nuclei. We numerically simulate the memory protocol by solving the time-dependent Schrödinger equation for the system comprising the electron spin and the bath spins [2]. We find that the memory operation is robust with respect to these relalistic imperfections and that high fidelity operation is possible with realistic values of nuclear spin polarization. This work was supported by the NSA, ARDA and ARO.1. J. M. Taylor, C. M. Marcus, and M. D. Lukin, Phys. Rev. Lett. 90, 206803 (2003).2. V. V. Dobrovitski and H. A. De Raedt, Phys. Rev. E 67, 056702 (2003)
A new spin-oriented nuclei facility: POLAREX
Directory of Open Access Journals (Sweden)
Etilé A.
2014-03-01
Full Text Available Using the On-Line Nuclear Orientation method, POLAREX (POLARization of EXotic nuclei is a new facility allowing to study the anisotropic decay of spin-oriented nuclei. Based on the combination of on-line implantation of radioactive nuclei with Low Temperature Nuclear Orientation technique and Nuclear Magnetic Resonance, POLAREX allows to measure nuclear electromagnetic moments and ground-state spins, in the aim to get information about the wave function composition of the nuclear state. Polarized nuclei can also be used to study fundamental interactions involving nuclear β-decay asymmetries. The POLAREX infrastructure will be installed at Accélérateur Linéaire auprés du Tandem d’Orsay in order to study neutron-rich nuclei, some of which have not been studied yet. Will be presented here, all the possibilities of this new facility and a non exhaustive scientific program.
Spin caloritronics in graphene
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Angsula; Frota, H. O. [Department of Physics, Federal University of Amazonas, Av. Rodrigo Octavio 3000-Japiim, 69077-000 Manaus, AM (Brazil)
2015-06-14
Spin caloritronics, the combination of spintronics with thermoelectrics, exploiting both the intrinsic spin of the electron and its associated magnetic moment in addition to its fundamental electronic charge and temperature, is an emerging technology mainly in the development of low-power-consumption technology. In this work, we study the thermoelectric properties of a Rashba dot attached to two single layer/bilayer graphene sheets as leads. The temperature difference on the two graphene leads induces a spin current, which depends on the temperature and chemical potential. We demonstrate that the Rashba dot behaves as a spin filter for selected values of the chemical potential and is able to filter electrons by their spin orientation. The spin thermopower has also been studied where the effects of the chemical potential, temperature, and also the Rashba term have been observed.
Nonequilibrium spin noise spectroscopy
Li, Fuxiang; Pershin, Yuriy V.; Slipko, Valeriy A.; Sinitsyn, Nikolai A.
2013-01-01
Spin Noise Spectroscopy (SNS) is an experimental approach to obtain correlators of mesoscopic spin fluctuations in time by purely optical means. We explore the information that this technique can provide when it is applied to a weakly non-equilibrium regime when an electric current is driven through a sample by an electric field. We find that the noise power spectrum of conducting electrons experiences a shift, which is proportional to the strength of the spin-orbit coupling for electrons mov...
Kamra, A.; Witek, F.P.; Meyer, S.; Huebl, H.; Geprägs, S.; Gross, R.; Bauer, G. E. W.; Goennenwein, S. T. B.
2014-01-01
We measure the low-frequency thermal fluctuations of pure spin current in a Platinum film deposited on yttrium iron garnet via the inverse spin Hall effect (ISHE)-mediated voltage noise as a function of the angle $\\alpha$ between the magnetization and the transport direction. The results are consistent with the fluctuation dissipation theorem in terms of the recently discovered spin Hall magnetoresistance (SMR). We present a microscopic description of the $\\alpha$ dependence of the voltage no...
Torczynski, John R.
2000-01-01
A spin coating apparatus requires less cleanroom air flow than prior spin coating apparatus to minimize cleanroom contamination. A shaped exhaust duct from the spin coater maintains process quality while requiring reduced cleanroom air flow. The exhaust duct can decrease in cross section as it extends from the wafer, minimizing eddy formation. The exhaust duct can conform to entrainment streamlines to minimize eddy formation and reduce interprocess contamination at minimal cleanroom air flow rates.
Universal enhancement of the optical readout fidelity of single electron spins
Steiner, M; Beck, J; Jelezko, F; Wrachtrup, J
2009-01-01
Precise readout of spin states is crucial for any approach towards physical realization of a spin-based quantum computer and for magnetometry with single spins. Here, we report a new method to strongly improve the optical readout fidelity of electron spin states associated with single nitrogen-vacancy (NV) centers in diamond. The signal-to-noise ratio is enhanced significantly by performing conditional flip-flop processes between the electron spin and the nuclear spin of the NV center's nitrogen atom. The enhanced readout procedure is triggered by a short preparatory pulse sequence. As the nitrogen nuclear spin is intrinsically present in the system, this method is universally applicable to any nitrogen-vacancy center.
Universal control and error correction in multi-qubit spin registers in diamond.
Taminiau, T H; Cramer, J; van der Sar, T; Dobrovitski, V V; Hanson, R
2014-03-01
Quantum registers of nuclear spins coupled to electron spins of individual solid-state defects are a promising platform for quantum information processing. Pioneering experiments selected defects with favourably located nuclear spins with particularly strong hyperfine couplings. To progress towards large-scale applications, larger and deterministically available nuclear registers are highly desirable. Here, we realize universal control over multi-qubit spin registers by harnessing abundant weakly coupled nuclear spins. We use the electron spin of a nitrogen-vacancy centre in diamond to selectively initialize, control and read out carbon-13 spins in the surrounding spin bath and construct high-fidelity single- and two-qubit gates. We exploit these new capabilities to implement a three-qubit quantum-error-correction protocol and demonstrate the robustness of the encoded state against applied errors. These results transform weakly coupled nuclear spins from a source of decoherence into a reliable resource, paving the way towards extended quantum networks and surface-code quantum computing based on multi-qubit nodes. PMID:24487650
Biswas, Ayan K.; Atulasimha, Jayasimha; Bandyopadhyay, Supriyo
2015-01-01
In artificial neural networks, neurons are usually implemented with highly dissipative CMOS-based operational amplifiers. A more energy-efficient implementation is a 'spin-neuron' realized with a magneto-tunneling junction (MTJ) that is switched with a spin-polarized current (representing weighted sum of input currents) that either delivers a spin transfer torque or induces domain wall motion in the soft layer of the MTJ. Here, we propose and analyze a different type of spin-neuron in which t...
Quenching of the spin-dependent scattering of weakly interacting massive particles on heavy nuclei
Nikolaev, M. A.; Klapdor-Kleingrothaus, H. V.
1993-12-01
We present calculations of the quenching of the spin-dependent elastic scattering cross section for dark matter WIMPs on heavy nuclei. The theory of finite Fermi systems was used to describe the behavior of the nuclear spin matrix elements in the nuclear medium. The results of the calculations for planned dark matter detector nuclei are not only always smaller than corresponding single particle estimations but in some cases also differ from the ones obtained by using measured nuclear magnetic moments.
Probing spin-charge separation using spin transport
Si, Qimiao
2000-01-01
Pedagogical discussions are given on what constitutes a signature of spin-charge separation. A proposal is outlined to probe spin-charge separation in the normal state of the high $T_c$ cuprates using spin transport. Specifically, the proposal is to compare the temperature dependences of the spin resistivity and electrical resistivity: Spin-charge separation will be manifested in the different temperature dependences of these two resistivities. We also estimate the spin diffusion length and s...
Response of a spin valve to a spin battery
Pham, Khuôn-Viêt
2016-01-01
It is shown that spin valves under suitable symmetry conditions exhibit an ON-OFF response to a spin battery, and are therefore perfect spin transistors. While a spin valve driven by a charge battery displays the usual GMR (Giant Magneto-Resistance), this means that a pure spin current or pure spin accumulation can generate an infinite magnetoresistance (IMR). Magnetic tunnel junctions as well as CPP (current perpendicular to plane) or CIP (current in plane) metallic trilayers are discussed.
Quantum theory of spin waves in finite chiral spin chains
Roldán-Molina, A.; Santander, M. J.; Núñez, A.S.; Fernández Rossier, Joaquín
2013-01-01
We calculate the effect of spin waves on the properties of finite-size spin chains with a chiral spin ground state observed on biatomic Fe chains deposited on iridium(001). The system is described with a Heisenberg model supplemented with a Dzyaloshinskii-Moriya coupling and a uniaxial single ion anisotropy that presents a chiral spin ground state. Spin waves are studied using the Holstein-Primakoff boson representation of spin operators. Both the renormalized ground state and the elementary ...
Langevin description of the evaporation residue spin distribution
International Nuclear Information System (INIS)
The recently measured spin distribution of evaporation residue cross section in the reaction 16O + 184W is studied in the framework of Langevin equations. Results show that the Langevin approach can describe this observable very well. Moreover, a pre-saddle nuclear viscosity coefficient of 5 × 1021 s-1 is extracted by comparing theoretical calculations with experimental data. We also explore the effect of the isospin of a system on the spin distribution by evaluating the evaporation residue spin distribution of nuclei 194Pb, 200Pb and 206Pb. It has been found that with increasing the isospin of the system, the sensitivity of the evaporation residue spin distribution to the nuclear viscosity is decreased significantly. This result suggests that choosing a low-isospin compound system favors an accurate determination of pre-saddle dissipation strength. (author)
Atom-diatom scattering dynamics of spinning molecules.
Eyles, C J; Floss, J; Averbukh, I Sh; Leibscher, M
2015-01-14
We present full quantum mechanical scattering calculations using spinning molecules as target states for nuclear spin selective atom-diatom scattering of reactive D+H2 and F+H2 collisions. Molecules can be forced to rotate uni-directionally by chiral trains of short, non-resonant laser pulses, with different nuclear spin isomers rotating in opposite directions. The calculations we present are based on rotational wavepackets that can be created in this manner. As our simulations show, target molecules with opposite sense of rotation are predominantly scattered in opposite directions, opening routes for spatially and quantum state selective scattering of close chemical species. Moreover, two-dimensional state resolved differential cross sections reveal detailed information about the scattering mechanisms, which can be explained to a large degree by a classical vector model for scattering with spinning molecules. PMID:25591357
Development of NMOR magnetometer for spin-maser EDM experiment
Yoshimi, A.; Nanao, T.; Inoue, T.; Furukawa, T.; Uchida, M.; Tsuchiya, M.; Hayashi, H.; Chikamori, M.; Asahi, K.
We have been developing a high sensitivity atomic magnetometer for atomic EDM experiments using a lowfrequency nuclear spin maser. In the developed nuclear spin maser of 129Xe, suppression of drift and fluctuation in the magnetic field is one of the important issues. The magnetometer being developed for spin maser EDM experiments utilizes the nonlinear magneto optical rotation (NMOR) e_ect in Rb atomic vapor. The enhancement of the optical rotation in a small magnetic field relies on the long spin-coherence time of Rb atoms in a vapor cell. The NMOR spectrum was measured by using fabricated Rb cells coated with an anti-relaxation material. The NMOR spectrum dependence on laser frequency, cell coating, and laser beam diameter were investigated. The magnetic sensitivity at present is 0:2 μG/√Hz from observed NMOR and noise spectra.
Pulsed Spin Locking in Spin-1 NQR: Broadening Mechanisms
Malone, Michael W.
Nuclear Quadrupole Resonance (NQR) is a branch of magnetic resonance physics that allows for the detection of spin I > 1/2 nuclei in crystalline and semi-crystalline materials. Through the application of a resonant radio frequency (rf) pulse, the nuclei's response is to create an oscillating magnetic moment at a frequency unique to the target substance. This creates the NQR signal, which is typically weak and rapidly decaying. The decay is due to the various line broadening mechanisms, the relative strengths of which are functions of the specific material, in addition to thermal relaxation processes. Through the application of a series of rf pulses the broadening mechanisms can be refocused, narrowing the linewidth and extending the signal in time. Three line broadening mechanisms are investigated to explain the NQR signal's linewidth and behavior. The first, electric field gradient (EFG) inhomogeneity, is due to variations in the local electric environment among the target nuclei, for instance from crystal imperfections. While EFG inhomogeneity can vary between samples of the same chemical composition and structure, the other broadening mechanisms of homonuclear and heteronuclear dipolar coupling are specific to this composition and structure. Simple analytical models are developed that explain the NQR signal response to pulse sequences by accounting for the behavior of each broadening mechanism. After a general theoretical introduction, a model of pairs of spin-1 nuclei is investigated, and the refocusing behaviors of EFG and homonuclear dipolar coupling are analyzed. This reveals the conditions where EFG is refocused but homonuclear dipolar coupling is not. In this case the resulting signal shows a rapid decay, the rate of which becomes a measure of interatomic distances. This occurs even in the more complex case of a powder sample with its many randomly oriented crystallites, under particular pulsing conditions. Many target NQR compounds are rich in hydrogen
Bahr, Benjamin; Kamiński, Wojciech; Kisielowski, Marcin; Lewandowski, Jerzy
2010-01-01
The goal of this paper is to introduce a systematic approach to spin foams. We define operator spin foams, that is foams labelled by group representations and operators, as the main tool. An equivalence relation we impose in the set of the operator spin foams allows to split the faces and the edges of the foams. The consistency with that relation requires introduction of the (familiar for the BF theory) face amplitude. The operator spin foam models are defined quite generally. Imposing a maximal symmetry leads to a family we call natural operator spin foam models. This symmetry, combined with demanding consistency with splitting the edges, determines a complete characterization of a general natural model. It can be obtained by applying arbitrary (quantum) constraints on an arbitrary BF spin foam model. In particular, imposing suitable constraints on Spin(4) BF spin foam model is exactly the way we tend to view 4d quantum gravity, starting with the BC model and continuing with the EPRL or FK models. That makes...
Antiferromagnetic spin Seebeck effect.
Energy Technology Data Exchange (ETDEWEB)
Wu, Stephen M.; Zhang, Wei; KC, Amit; Borisov, Pavel; Pearson, John E.; Jiang, J. Samuel; Lederman, David; Hoffmann, Axel; Bhattacharya, Anand
2016-03-03
We report on the observation of the spin Seebeck effect in antiferromagnetic MnF2. A device scale on-chip heater is deposited on a bilayer of MnF2 (110) (30nm)/Pt (4 nm) grown by molecular beam epitaxy on a MgF2(110) substrate. Using Pt as a spin detector layer, it is possible to measure the thermally generated spin current from MnF2 through the inverse spin Hall effect. The low temperature (2–80 K) and high magnetic field (up to 140 kOe) regime is explored. A clear spin-flop transition corresponding to the sudden rotation of antiferromagnetic spins out of the easy axis is observed in the spin Seebeck signal when large magnetic fields (>9T) are applied parallel to the easy axis of the MnF2 thin film. When the magnetic field is applied perpendicular to the easy axis, the spin-flop transition is absent, as expected.
Kamra, A.; Witek, F.P.; Meyer, S.; Huebl, H.; Geprägs, S.; Gross, R.; Bauer, G.E.W.; Goennenwein, S.T.B.
2014-01-01
We measure the low-frequency thermal fluctuations of pure spin current in a platinum film deposited on yttrium iron garnet via the inverse spin Hall effect (ISHE)-mediated voltage noise as a function of the angle α between the magnetization and the transport direction. The results are consistent wit
Kleiner, Alex
2002-01-01
It is shown here that electrons on the surface of a nanotube in a perpendicular magnetic field undergo spin-chirality separation along the circumference. Stripes of spin-polarization propagate along the tube, with a spatial pattern that can be modulated by the electron filling.
Spin torque transistor revisited
Chiba, T.; Bauer, G.E.W.; Takahashi, S.
2013-01-01
We theoretically study the operation of a 4-terminal device consisting of two lateral thin-film spin valves that are coupled by a magnetic insulator such as yttrium iron garnet via the spin transfer torque. By magnetoelectronic circuit theory we calculate the current voltage characteristics and find
Quantum Monte Carlo study of spin-polarized deuterium
Beslic, I.; Markic, L. Vranjes; Casulleras, J.; Boronat, J.
2012-01-01
The ground state properties of spin-polarized deuterium (D$\\downarrow$) at zero temperature are obtained by means of the diffusion Monte Carlo calculations within the fixed-node approximation. Three D$\\downarrow$ species have been investigated (D$\\downarrow_1$, D$\\downarrow_2$, D$\\downarrow_3$), corresponding respectively to one, two and three equally occupied nuclear spin states. Influence of the backflow correlations on the ground state energy of the systems is explored. The equilibrium den...
The theory of spin noise spectroscopy: a review
Sinitsyn, Nikolai A.; Pershin, Yuriy V.
2016-10-01
Direct measurements of spin fluctuations are becoming the mainstream approach for studies of complex condensed matter, molecular, nuclear, and atomic systems. This review covers recent progress in the field of optical spin noise spectroscopy (SNS) with an additional goal to establish an introduction into its theoretical foundations. Various theoretical techniques that have been recently used to interpret results of SNS measurements are explained alongside examples of their applications.
Exact and non-smooth control of quantum spin systems
Ciaramella, Gabriele
2015-01-01
An efficient and accurate computational framework for solving control problems governed by quantum spin systems is presented. Spin systems are extremely important in modern quantum technologies such as nuclear magnetic resonance spectroscopy, quantum imaging and quantum computing. In these applications, two classes of quantum control problems arise: optimal control problems and exact-controllability problems, with a bilinear con- trol structure. These models correspond to the Schrödinger-Paul...
Longitudinal and Transverse Spin Responses in Relativistic Many Body Theory
Yoshida, K; Toki, H.
1998-01-01
Spin longitudinal and transverse response function are studied by means of the relativistic many-body theory. The spin response functions in the relativistic theory are largely reduced from those in the non-relativistic theory. The local density approximation with the eikonal approximation is applied to the the nuclear absorption in the $(\\vec{p},\\vec{n})$ reactions on C and Ca. We compare the calculated results with the recent experimental data.
MacIntosh, R S
1997-01-01
The iterative-perturbative (IP) procedure for S-matrix to potential inversion is applied to spin-one projectiles for the restricted case of vector spin-orbit interaction only. In order to evaluate this extension of IP inversion we have inverted the multi-channel RGM $S_{lj}$ of Kanada et al for deuterons scattering from $^4$He with deuteron distortion and then compared the central components with those derived from RGM with spin set to zero. Attention is given to the question of how well the resulting potentials are established. Reliable spin-1 inversion is demonstrated. Results relating to inversion, to deuteron-nucleus interactions and to RGM are presented and suggest the range of nuclear interaction information which the procedure makes possible. Unusual non-locality and parity dependence effects are found; these are of possible relevance to generic properties of nuclear potentials.
DEFF Research Database (Denmark)
Jensen, J.; Houmann, Jens Christian Gylden; Bjerrum Møller, Hans
1975-01-01
The energies of spin waves propagating in the c direction of Tb have been studied by inelastic neutron scattering, as a function of a magnetic field applied along the easy and hard directions in the basal plane, and as a function of temperature. From a general spin Hamiltonian, consistent...... with the symmetry, we deduce the dispersion relation for the spin waves in a basal-plane ferromagnet. This phenomenological spin-wave theory accounts for the observed behavior of the magnon energies in Tb. The two q⃗-dependent Bogoliubov components of the magnon energies are derived from the experimental results...... with increasing temperatures implies that the two-ion coupling is effectively isotropic above ∼ 150 K. We present arguments for concluding that, among the mechanisms which may introduce anisotropic two-ion couplings in the rare-earth metals, the modification of the indirect exchange interaction by the spin...
Lan, Jin; Yu, Weichao; Wu, Ruqian; Xiao, Jiang
2015-10-01
A diode, a device allowing unidirectional signal transmission, is a fundamental element of logic structures, and it lies at the heart of modern information systems. The spin wave or magnon, representing a collective quasiparticle excitation of the magnetic order in magnetic materials, is a promising candidate for an information carrier for the next-generation energy-saving technologies. Here, we propose a scalable and reprogrammable pure spin-wave logic hardware architecture using domain walls and surface anisotropy stripes as waveguides on a single magnetic wafer. We demonstrate theoretically the design principle of the simplest logic component, a spin-wave diode, utilizing the chiral bound states in a magnetic domain wall with a Dzyaloshinskii-Moriya interaction, and confirm its performance through micromagnetic simulations. Our findings open a new vista for realizing different types of pure spin-wave logic components and finally achieving an energy-efficient and hardware-reprogrammable spin-wave computer.
Fractionalized spin-wave continuum in kagome spin liquids
Mei, Jia-Wei; Wen, Xiao-Gang
Motivated by spin-wave continuum (SWC) observed in recent neutron scattering experiments in Herbertsmithite, we use Gutzwiller-projected wave functions to study dynamic spin structure factor S (q , ω) of spin liquid states on the kagome lattice. Spin-1 excited states in spin liquids are represented by Gutzwiller-projected two-spinon excited wave functions. We investigate three different spin liquid candidates, spinon Fermi-surface spin liquid (FSL), Dirac spin liquid (DSL) and random-flux spin liquid (RSL). FSL and RSL have low energy peaks in S (q , ω) at K points in the extended magnetic Brillouin zone, in contrast to experiments where low energy peaks are found at M points. There is no obviuos contradiction between DSL and neutron scattering measurements. Besides a fractionalized spin (i.e. spin-1/2), spinons in DSL carry a fractionalized crystal momentum which is potentially detectable in SWC in the neutron scattering measurements.
International Nuclear Information System (INIS)
We have proposed a method to synchronize multiple spin-transfer torque oscillators based on spin pumping, inverse spin Hall, and spin Hall effects. The proposed oscillator system consists of a series of nano-magnets in junction with a normal metal with high spin-orbit coupling, and an accumulative feedback loop. We conduct simulations to demonstrate the effect of modulated charge currents in the normal metal due to spin pumping from each nano-magnet. We show that the interplay between the spin Hall effect and inverse spin Hall effect results in synchronization of the nano-magnets
Spin Hall and spin Nernst effects in graphene with intrinsic and Rashba spin-orbit interactions
Institute of Scientific and Technical Information of China (English)
Zhu Guo-Bao
2012-01-01
The spin Hall and spin Nernst effects in graphene are studied based on Green's function formalism.We calculate intrinsic contributions to spin Hall and spin Nernst conductivities in the Kane-Mele model with various structures.When both intrinsic and Rashba spin-orbit interactions are present,their interplay leads to some characteristics of the dependence of spin Hall and spin Nernst conductivities on the Fermi level.When the Rashba spin-orbit interaction is smaller than intrinsic spin-orbit coupling,a weak kink in the conductance appears.The kink disappears and a divergence appears when the Rashba spin-orbit interaction enhances.When the Rashba spin-orbit interaction approaches and is stronger than intrinsic spin-orbit coupling,the divergence becomes more obvious.
Energy Technology Data Exchange (ETDEWEB)
Brunel, V
1999-06-29
This thesis presents three studies that are respectively the spin-1 disordered chain, the non magnetic impurities in the spin-1/2 chain and the reaction-diffusion process. The spin-1 chain of weak disorder is performed by the Abelian bosonization and the renormalization group. This allows to take into account the competition between the disorder and the interactions and predicts the effects of various spin-1 anisotropy chain phases under many different disorders. A second work uses the non magnetic impurities as local probes of the correlations in the spin-1/2 chain. When the impurities are connected to the chain boundary, the author predicts a temperature dependence of the relaxation rate (1/T) of the nuclear spin impurities, different from the case of these impurities connected to the whole chain. The last work deals with one dimensional reaction-diffusion problem. The Jordan-Wigner transformation allows to consider a fermionic field theory that critical exponents follow from the renormalization group. (A.L.B.)
Curvature-enhanced Spin-orbit Coupling and Spinterface Effect in Fullerene-based Spin Valves
Liang, Shiheng; Geng, Rugang; Yang, Baishun; Zhao, Wenbo; Chandra Subedi, Ram; Li, Xiaoguang; Han, Xiufeng; Nguyen, Tho Duc
2016-01-01
We investigated curvature-enhanced spin-orbit coupling (SOC) and spinterface effect in carbon-based organic spin valves (OSVs) using buckyball C60 and C70 molecules. Since the naturally abundant 12C has spinless nuclear, the materials have negligible hyperfine interaction (HFI) and the same intrinsic SOC, but different curvature SOC due to their distinct curvatures. We fitted the thickness dependence of magnetoresistance (MR) in OSVs at various temperatures using the modified Jullière equation. We found that the spin diffusion length in the C70 film is above 120 nm, clearly longer than that in C60 film at all temperatures. The effective SOC ratio of the C70 film to the C60 film was estimated to be about 0.8. This was confirmed by the magneto-electroluminescence (MEL) measurement in fullerene-based light emitting diodes (LED). Next, the effective spin polarization in C70-based OSVs is smaller than that in C60-based OSVs implying that they have different spinterface effect. First principle calculation study shows that the spin polarization of the dz2 orbital electrons of Co atoms contacted with C60 is larger causing better effective spin polarization at the interface.
Neutron spin precession in samples of polarised nuclei and neutron spin phase imaging
Energy Technology Data Exchange (ETDEWEB)
Piegsa, Florian Michael
2009-07-09
The doublet neutron-deuteron (nd) scattering length b{sub 2,d}, which is at present only known with an accuracy of 5%, is particularly well suited to fix three-body forces in novel effective field theories at low energies. The understanding of such few-nucleon systems is essential, e.g. for predictions of element abundances in the big-bang and stellar fusion. b{sub 2,d} can be obtained via a linear combination of the spin-independent nd scattering length b{sub c,d} and the spin-dependent one, b{sub i,d}. The aim of this thesis was to perform a high-accuracy measurement of the latter to improve the relative accuracy of b{sub 2,d} below 1%. The experiment was performed at the fundamental neutron physics beam line FUNSPIN at the Paul Scherrer Institute in Switzerland. It utilises the effect that the spin of a neutron passing through a target with polarised nuclei performs a pseudomagnetic precession proportional to the spin-dependent scattering length of the nuclei. An ideal method to measure this precession angle very accurately is Ramsey's atomic beam technique, adapted to neutrons. The most crucial part of the experimental setup is the so-called frozen spin target, which consists of a specially designed dilution refrigerator and contains a sample with dynamically polarised nuclear spins. The polarisation of the sample is determined by nuclear magnetic resonance (NMR) techniques. It turned out that the relaxation of the nuclear spins during the necessary ''cross-calibration'' of the two employed NMR systems is ultimately limiting the achievable accuracy of b{sub i,d}. During the extensive use of the Ramsey resonance method in the neutron-deuteron experiment, an idea emerged that the applied technique could be exploited in a completely different context, namely polarised neutron radiography. Hence, the second part of the thesis covers the development of a novel neutron radiography technique, based on the spin-dependent interaction of the
Spin temperatures under dynamic polarization in a one-dimensional system, the TANOL
International Nuclear Information System (INIS)
A quantitative model of Tanol submitted to dynamic polarization has been developed. The spin systems are described using a network of interconnected reservoirs. The model involves six (or ten) Zeeman nuclear reservoirs mutually coupled by nuclear-nuclear dipole interactions and coupled to electron spins by hyperfine interactions. When the electronic line is saturated, different nuclear temperatures appear in the molecule. These temperatures have been calculated as a function of the magnetic field orientation against the crystallographic axes. Experimental results are correctly reproduced. A quantitative agreement is obtained for the anisotropy of total polarization. The calculation also shows that, in certain directions, positive and negative spin temperatures simultaneously appear, that explains the complex shape of the signals observed. Nuclear relaxation processes involving two electron spins of the same exchange chain are taken into account for the calculation. The different possible chain directions (a, a+c, or c vectors) were envisaged. Only the c-vector hypothesis succeeded in interpreting experimental results
Pauli Spin Blockade and the Ultrasmall Magnetic Field Effect
Danon, Jeroen
2013-08-06
Based on the spin-blockade model for organic magnetoresistance, we present an analytic expression for the polaron-bipolaron transition rate, taking into account the effective nuclear fields on the two sites. We reveal the physics behind the qualitatively different magnetoconductance line shapes observed in experiment, as well as the ultrasmall magnetic field effect (USFE). Since our findings agree in detail with recent experiments, they also indirectly provide support for the spin-blockade interpretation of organic magnetoresistance. In addition, we predict the existence of a similar USFE in semiconductor double quantum dots tuned to the spin-blockade regime.
Institute of Scientific and Technical Information of China (English)
Tina Boikos
2008-01-01
@@ The alarm has just gone off. Do I really have to get up? I wonder. Originally, signing up for an early-morning spinning class seemed like a good idea; it jump-starts the day with some well-needed exercise.
Gluon Spin Contribution to The Nucleon Spin
Energy Technology Data Exchange (ETDEWEB)
Arash, Firooz, E-mail: farash@cic.aut.ac.i [Physics Department, Tafresh University, Tafresh (Iran, Islamic Republic of); Shahveh, Abolfazl [Physics Department, Tafresh University, Tafresh (Iran, Islamic Republic of); Taghavi-Shahri, Fateme [School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM) P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)
2010-10-15
We have calculated {delta}g/g in the nucleon at all measured kinematics. The smallness of {delta}g/g in the measured kinematics should not be interpreted as the the gluon contribution to the nucleon spin is small. In fact the first moment of gluon polarization in the nucleon, {Delta}g(Q{sup 2}) can be sizable.
Gluon Spin Contribution to The Nucleon Spin
Arash, Firooz; Shahveh, Abolfazl; Taghavi-Shahri, Fateme
2010-10-01
We have calculated δg/ g in the nucleon at all measured kinematics. The smallness of δg/ g in the measured kinematics should not be interpreted as the the gluon contribution to the nucleon spin is small. In fact the first moment of gluon polarization in the nucleon, Δ g( Q2) can be sizable.
Gluon Spin Contribution to The Nucleon Spin
International Nuclear Information System (INIS)
We have calculated δg/g in the nucleon at all measured kinematics. The smallness of δg/g in the measured kinematics should not be interpreted as the the gluon contribution to the nucleon spin is small. In fact the first moment of gluon polarization in the nucleon, Δg(Q2) can be sizable.
Nuclear structure studies at intermediate energies:
International Nuclear Information System (INIS)
This paper discusses progress on studies on nuclear structure at the University of Minnesota. Some of the topics discussed are: nucleon-nucleon interactions, high spin stretched states, deformed and transition nuclei, giant resonances, measurement of spin observables, pion scattering, delta resonances, and electron scattering
Spin squeezing an ultracold molecule
Bhattacharya, M
2015-01-01
Most research on spin squeezing thus far has focused on realizations involving either atomic or nuclear degrees of freedom. In this article we discuss a concrete proposal for spin squeezing the ultracold ground state polar paramagnetic molecule OH, a system currently under fine control in the laboratory. Starting from an experimentally relevant effective Hamiltonian, we identify a parameter regime where different combinations of static electric and magnetic fields can be used to realize the single-axis twisting Hamiltonian of Kitagawa and Ueda [M. Kitagawa and M. Ueda, Phys. Rev. A 47, 5138 (1993)], the uniform field Hamiltonian proposed by Law et al. [C. K. Law, H. T Ng and P. T. Leung, Phys. Rev. A 63, 055601 (2001)], and a model of field propagation in a Kerr medium considered by Agarwal and Puri [G. S. Agarwal and R. R. Puri, Phys. Rev. A 39, 2969 (1989)]. To support our conclusions, we provide analytical expressions as well as numerical calculations, including optimization of field strengths and accounti...
Spin dynamics in the quantum spin system KCu{sub 5}V{sub 3}O{sub 13}
Energy Technology Data Exchange (ETDEWEB)
Klauss, H.-H.; Lemmens, P.; Birke, M.; Baabe, D.; Mienert, D.; Litterst, F.J.; Amato, A.; Pommer, J.; Ionescu, A.; Choi, K.-Y.; Guentherodt, G.; Kageyama, H.; Hiroi, Z.; Takigawa, M
2003-02-01
The complex Oxo-Cu-vanadate KCu{sub 5}V{sub 3}O{sub 13} with 5 independent Cu-sites (s=((1)/(2))) per unit cell has an exchange topology described as a ladder of spin tetrahedra or triangles. Magnetic susceptibility measurements on single crystals show a steplike anomaly at 213 K and an antiferromagnetic transition at 7.5 K. ZF {mu}SR reveals only nuclear relaxation above 10 K and two spontaneous precession signals in the long range ordered regime. Below 3.7 K, a spin reorientation leads to a broad frequency distribution typical for an incommensurate spin structure.
Representation of Spin Group Spin(p, q)
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The representation (&)(p, q) of spin group Spin(p, q) in any dimensional space is given by induction, and the relation between two representations, which are obtained in two kinds of inductions from Spin(p, q) to Spin(p + 1, q + 1)are studied.
Spin drift and spin diffusion currents in semiconductors
Directory of Open Access Journals (Sweden)
M Idrish Miah
2008-01-01
Full Text Available On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.
Quantifying Spin Hall Angles from Spin Pumping: Experiments and Theory
Mosendz, O.; Pearson, J.E.; Fradin, F.Y.; Bauer, G.E.W.; Bader, S.D.; Hoffmann, A.
2010-01-01
Spin Hall effects intermix spin and charge currents even in nonmagnetic materials and, therefore, ultimately may allow the use of spin transport without the need for ferromagnets. We show how spin Hall effects can be quantified by integrating Ni80Fe20|normal metal (N) bilayers into a coplanar wavegu
SPIN Tutorial: How to Become a SPIN Doctor
Ruys, T.C.; Bosnacki, D.; Leue, S.
2002-01-01
SPIN is a model checker for the verification of software systems. SPIN uses a high level language called PROMELA to specify systems descriptions. The goal of this tutorial is to introduce novice users to both PROMELA and SPIN. The tutorial itself is divided into two parts. The BASIC SPIN part is tar
Spin transfer torque with spin diffusion in magnetic tunnel junctions
Manchon, Aurelien
2012-08-09
Spin transport in magnetic tunnel junctions in the presence of spin diffusion is considered theoretically. Combining ballistic tunneling across the barrier and diffusive transport in the electrodes, we solve the spin dynamics equation in the metallic layers. We show that spin diffusion mixes the transverse spin current components and dramatically modifies the bias dependence of the effective spin transfer torque. This leads to a significant linear bias dependence of the out-of-plane torque, as well as a nonconventional thickness dependence of both spin torque components.
Krishnan, Chethan; Raju, Avinash; Roy, Shubho; Thakur, Somyadip
2014-02-01
We construct cosmological solutions of higher spin gravity in 2+1 dimensional de Sitter space. We show that a consistent thermodynamics can be obtained for their horizons by demanding appropriate holonomy conditions. This is equivalent to demanding the integrability of the Euclidean boundary conformal field theory partition function, and it reduces to Gibbons-Hawking thermodynamics in the spin-2 case. By using the prescription of Maldacena, we relate the thermodynamics of these solutions to those of higher spin black holes in AdS3.
Energy Technology Data Exchange (ETDEWEB)
Bernevig, B.Andrei; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.
2010-01-15
The quantum Hall liquid is a novel state of matter with profound emergent properties such as fractional charge and statistics. Existence of the quantum Hall effect requires breaking of the time reversal symmetry caused by an external magnetic field. In this work, we predict a quantized spin Hall effect in the absence of any magnetic field, where the intrinsic spin Hall conductance is quantized in units of 2 e/4{pi}. The degenerate quantum Landau levels are created by the spin-orbit coupling in conventional semiconductors in the presence of a strain gradient. This new state of matter has many profound correlated properties described by a topological field theory.
McWeeny, Roy
2004-01-01
Originally delivered as a series of lectures, this volume systematically traces the evolution of the ""spin"" concept from its role in quantum mechanics to its assimilation into the field of chemistry. Author Roy McWeeny presents an in-depth illustration of the deductive methods of quantum theory and their application to spins in chemistry, following the path from the earliest concepts to the sophisticated physical methods employed in the investigation of molecular structure and properties. Starting with the origin and development of the spin concept, the text advances to an examination of sp
2013-01-01
This book covers all principal aspects of currently investigated frustrated systems, from exactly solved frustrated models to real experimental frustrated systems, going through renormalization group treatment, Monte Carlo investigation of frustrated classical Ising and vector spin models, low-dimensional systems, spin ice and quantum spin glass. The reader can - within a single book - obtain a global view of the current research development in the field of frustrated systems.This new edition is updated with recent theoretical, numerical and experimental developments in the field of frustrated
Rotational Doppler Effect and Barnett Field in Spinning NMR
Chudo, Hiroyuki; Harii, Kazuya; Matsuo, Mamoru; Ieda, Jun'ichi; Ono, Masao; Maekawa, Sadamichi; Saitoh, Eiji
2015-04-01
We report the observation of the rotational Doppler effect using nuclear magnetic resonance (NMR). We have developed a coil-spinning technique that enables measurements by rotating a detector and fixing a sample. We found that the rotational Doppler effect gives rise to NMR frequency shifts equal to the rotation frequency. We formulate the rotational Doppler effect and the Barnett field using a vector model for the nuclear magnetic moment. This formulation reveals that, with just the sample rotating, both effects cancel each other, thereby explaining the absence of an NMR frequency shift in conventional sample-spinning NMR measurements.
ANALYSIS ON THE SPINNING FORCES IN FLEXIBLE SPINNING OF CONES
Institute of Scientific and Technical Information of China (English)
Xia Qinxiang; Susumu Shima
2003-01-01
Flexible spinning is a new type of spinning process where spin-forming is performed without using a mandrel. Combining shearing and rolling processes, the calculation formulas of thespinning forces in flexible spinning of cones is presented. The effects of the main processing parameters, such as gripping force G applied to the blank by the inner roller, the feed rate of rollersfand the roundness radius of outer roller ro, on the spinning forces are analyzed experimentally and theoretically.
Spin transfer torques in the nonlocal lateral spin valve.
Xu, Yuan; Xia, Ke; Ma, Zhongshui
2008-06-11
We report a theoretical study on the spin and electron transport in the nonlocal lateral spin valve with a non-collinear magnetic configuration. The nonlocal magnetoresistance, defined as the voltage difference on the detection lead over the injected current, is derived analytically. The spin transfer torques on the detection lead are calculated. It is found that spin transfer torques are symmetrical for parallel and antiparallel magnetic configurations, in contrast to that in a conventional sandwiched spin valve. PMID:21825793
Proposal for a spin MOSFET based on spin gapless semiconductors
Graziosi, Patrizio
2016-01-01
We propose a spintronic metal oxide semiconductor field effect transistor (spin MOSFET) where a spin gapless semiconductor (SGS) constitutes the channel and the drain is a ferromagnetic metal. SGS exhibit a non-zero band gap in only one of the spin sub-bands and feature complete spin polarization at finite temperature. We present an analytical model of the device and comment the properties relevant for devices applications. Our results boost SGS as a new paradigm for the spin MOSFET concept.
Quantum Computing in Silicon with Donor Electron Spins
Simmons, Michelle
2014-03-01
Extremely long electron and nuclear spin coherence times have recently been demonstrated in isotopically pure Si-28 making silicon one of the most promising semiconductor materials for spin based quantum information. The two level spin state of single electrons bound to shallow phosphorus donors in silicon in particular provide well defined, reproducible qubits and represent a promising system for a scalable quantum computer in silicon. An important challenge in these systems is the realisation of an architecture, where we can position donors within a crystalline environment with approx. 20-50nm separation, individually address each donor, manipulate the electron spins using ESR techniques and read-out their spin states. We have developed a unique fabrication strategy for a scalable quantum computer in silicon using scanning tunneling microscope hydrogen lithography to precisely position individual P donors in a Si crystal aligned with nanoscale precision to local control gates necessary to initialize, manipulate, and read-out the spin states. During this talk I will focus on demonstrating electronic transport characteristics and single-shot spin read-out of precisely-positioned P donors in Si. Additionally I will report on our recent progress in performing single spin rotations by locally applying oscillating magnetic fields and initial characterization of transport devices with two and three single donors. The challenges of scaling up to practical 2D architectures will also be discussed.
On the spin-dependent sensitivity of XENON100
Energy Technology Data Exchange (ETDEWEB)
Garny, Mathias [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibarra, Alejandro; Pato, Miguel; Vogl, Stefan [Technische Univ. Muenchen, Garching (Germany). Physik-Department
2012-11-15
The latest XENON100 data severely constrains dark matter elastic scattering off nuclei, leading to impressive upper limits on the spin-independent cross-section. The main goal of this paper is to stress that the same data set has also an excellent spin-dependent sensitivity, which is of utmost importance in probing dark matter models. We show in particular that the constraints set by XENON100 on the spin-dependent neutron cross-section are by far the best at present, whereas the corresponding spin-dependent proton limits lag behind other direct detection results. The effect of nuclear uncertainties on the structure functions of xenon isotopes is analysed in detail and found to lessen the robustness of the constraints, especially for spin-dependent proton couplings. Notwith-standing, the spin-dependent neutron prospects for XENON1T and DARWIN are very encouraging. We apply our constraints to well-motivated dark matter models and demonstrate that in both mass-degenerate scenarios and the minimal supersymmetric standard model the spin-dependent neutron limits can actually override the spin-independent limits. This opens the possibility of probing additional unexplored regions of the dark matter parameter space with the next generation of ton-scale direct detection experiments.
International Spin Physics 2014 Summary
Milner, Richard G
2015-01-01
The Stern-Gerlach experiment and the origin of electron spin are described in historical context. SPIN 2014 occurs on the fortieth anniversary of the first International High Energy Spin Physics Symposium at Argonne in 1974. A brief history of the international spin conference series is presented.
On Nonlinear Higher Spin Curvature
Manvelyan, Ruben(Yerevan Physics Institute, Alikhanian Br. St. 2, Yerevan, 0036, Armenia); Mkrtchyan, Karapet; Rühl, Werner; Tovmasyan, Murad
2011-01-01
We present the first nonlinear term of the higher spin curvature which is covariant with respect to deformed gauge transformations that are linear in the field. We consider in detail the case of spin 3 after presenting spin 2 as an example, and then construct the general spin s quadratic term of the deWit-Freedman curvature.
On nonlinear higher spin curvature
Energy Technology Data Exchange (ETDEWEB)
Manvelyan, Ruben, E-mail: manvel@physik.uni-kl.d [Department of Physics, Erwin Schroedinger Strasse, Technical University of Kaiserslautern, Postfach 3049, 67653 Kaiserslautern (Germany); Yerevan Physics Institute, Alikhanian Br. Str. 2, 0036 Yerevan (Armenia); Mkrtchyan, Karapet, E-mail: karapet@yerphi.a [Department of Physics, Erwin Schroedinger Strasse, Technical University of Kaiserslautern, Postfach 3049, 67653 Kaiserslautern (Germany); Yerevan Physics Institute, Alikhanian Br. Str. 2, 0036 Yerevan (Armenia); Ruehl, Werner, E-mail: ruehl@physik.uni-kl.d [Department of Physics, Erwin Schroedinger Strasse, Technical University of Kaiserslautern, Postfach 3049, 67653 Kaiserslautern (Germany); Tovmasyan, Murad, E-mail: mtovmasyan@ysu.a [Yerevan Physics Institute, Alikhanian Br. Str. 2, 0036 Yerevan (Armenia)
2011-05-09
We present the first nonlinear term of the higher spin curvature which is covariant with respect to deformed gauge transformations that are linear in the field. We consider the case of spin 3 after presenting spin 2 as an example, and then construct the general spin s quadratic term of the de Wit-Freedman curvature.
Anisotropic spin relaxation in graphene
Tombros, N.; Tanabe, S.; Veligura, A.; Jozsa, C.; Popinciuc, M.; Jonkman, H. T.; van Wees, B. J.
2008-01-01
Spin relaxation in graphene is investigated in electrical graphene spin valve devices in the nonlocal geometry. Ferromagnetic electrodes with in-plane magnetizations inject spins parallel to the graphene layer. They are subject to Hanle spin precession under a magnetic field B applied perpendicular
Nuclear structure, nuclear reaction
Etchegoyen, Maria Cristina Berisso de.; Sinclair, D.; Dr. D. Sinclair
1982-01-01
In this thesis, particle- particle angular correlations for reactions in non-zero degree geometry and with non-zero spin nuclei are performed and found to be a valuable tool for spin determination, (d-α) angular correlations in the reaction process 14N(6Li,d)18F* (α)14N are measured for three high excited states in 18F with a 6Li beam of 36MeV. Spins and parities for two of the observed states are determined, and in agreement with theoretical predictions, these states are s...
A quantum mechanical NMR simulation algorithm for protein-scale spin systems
Edwards, Luke J; Welderufael, Z T; Lee, Donghan; Kuprov, Ilya
2014-01-01
Nuclear magnetic resonance spectroscopy is one of the few remaining areas of physical chemistry for which polynomially scaling simulation methods have not so far been available. Here, we report such a method and illustrate its performance by simulating common 2D and 3D liquid state NMR experiments (including accurate description of spin relaxation processes) on isotopically enriched human ubiquitin - a protein containing over a thousand nuclear spins forming an irregular polycyclic three-dimensional coupling lattice. The algorithm uses careful tailoring of the density operator space to only include nuclear spin states that are populated to a significant extent. The reduced state space is generated by analyzing spin connectivity and decoherence properties: rapidly relaxing states as well as correlations between topologically remote spins are dropped from the basis set. In the examples provided, the resulting reduction in the quantum mechanical simulation time is by many orders of magnitude.
Microscopic studies of nonlocal spin dynamics and spin transport (invited)
Energy Technology Data Exchange (ETDEWEB)
Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris, E-mail: hammel@physics.osu.edu [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)
2015-05-07
Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems.
Spin-independent interferences and spin-dependent interactions with scalar dark matter
Martinez, R
2015-01-01
We explore mechanisms of interferences under which the spin-independent interaction in dispersions of scalar dark matter with nucleus is suppressed in relation to the spin-dependent one. We offer a detailed derivation of the nuclear amplitudes based on the interactions with quarks in the framework of an nonuniversal $U(1)'$ extension of the standard model. By assuming a range of parameters compatible with collider searches, electroweak observables and indirect dark matter search, we find scenarios for destructive interferences with and without isospin symmetry. The model admits solutions with mutually interfering scalar particles, canceling the effective spin-independent coupling with only scalar interactions, which requires an extra Higgs boson with mass $M_{H}>125$ GeV. The model also possess scenarios with only vector interactions through two neutral gauge bosons, $Z$ and $Z'$, which do not exhibits interference effects. Due to the nonuniversality of the $U(1)'$ symmetry, we distinguish two family structur...