The Experts below are selected from a list of 7152 Experts worldwide ranked by ideXlab platform
Jinyuan Zhou - One of the best experts on this subject based on the ideXlab platform.
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APPLICATION OF THE Rotation Operator APPROACH TO SELECTIVE EXCITATION OF COUPLED SPIN SYSTEMS BY A SHAPED RADIOFREQUENCY PULSE
Molecular Physics, 1995Co-Authors: Jinyuan ZhouAbstract:A simple and useful disentangling technique of the propagator, known as the Rotation Operator approach, is applied to weakly scalar-coupled spin-1/2 systems where a given spin or group of magnetically equivalent spins alone is irradiated by a shaped selective pulse. The theory employs the product Operator base as well as the single-transition Operator base. The treatment of a two-spin system is given in some detail, and that of larger spin systems given in outline. It is shown that the three Euler angles for a given shaped RF pulse are very concise and exact, and are readily applicable to the case of coupled spin systems.
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A novel disentangling technique for the propagator describing cross-polarization dynamics
Solid State Nuclear Magnetic Resonance, 1995Co-Authors: Jinyuan ZhouAbstract:The heteronuclear cross-polarization dynamics is described by the Rotation Operator approach proposed recently. The established theory is suitable for an isolated two-spin system. It is shown that the propagator can be disentangled into a cascade of six exponential Operators and the polarization transfer concerned can be evaluated by the usual procedure.
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Rotation Operator approach to spin dynamics and the euler geometric equations
Journal of Chemical Physics, 1994Co-Authors: Jinyuan Zhou, Chaohui Ye, B C SanctuaryAbstract:The Rotation Operator approach proposed previously is applied to spin dynamics in a time‐varying magnetic field. The evolution of the wave function is described, and that of the density Operator is also treated in terms of a spherical tensor Operator base. It is shown that this formulation provides a straightforward calculation of accumulated phases and probabilities of spin transitions and coherence evolutions. The technique focuses, not on the Rotation matrix, but on the three Euler angles and its characteristic equations are equivalent to the Euler geometric equations long known to describe the motion of a rigid body. The method usually depends on numerical calculations, but analytical solutions exist in some situations. In this paper, as examples, a hyperbolic secant pulse is solved analytically, and a Gaussian‐shaped pulse is calculated numerically.
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Rotation Operator approach and spin dynamics in a time varying magnetic field
Physical Review A, 1994Co-Authors: Jinyuan Zhou, Chaohui YeAbstract:The evolution Operator for an arbitrary spin system in an arbitrary time-varying magnetic field is disentangled into the Rotation Operator; consequently, the time-ordering problem is shifted into solving the Euler geometric equations. Some realistic transformations are proposed in order to find their analytic solutions. The probabilities and phases characterizing state transitions are also analyzed.
Chaohui Ye - One of the best experts on this subject based on the ideXlab platform.
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Rotation Operator approach to spin dynamics and the euler geometric equations
Journal of Chemical Physics, 1994Co-Authors: Jinyuan Zhou, Chaohui Ye, B C SanctuaryAbstract:The Rotation Operator approach proposed previously is applied to spin dynamics in a time‐varying magnetic field. The evolution of the wave function is described, and that of the density Operator is also treated in terms of a spherical tensor Operator base. It is shown that this formulation provides a straightforward calculation of accumulated phases and probabilities of spin transitions and coherence evolutions. The technique focuses, not on the Rotation matrix, but on the three Euler angles and its characteristic equations are equivalent to the Euler geometric equations long known to describe the motion of a rigid body. The method usually depends on numerical calculations, but analytical solutions exist in some situations. In this paper, as examples, a hyperbolic secant pulse is solved analytically, and a Gaussian‐shaped pulse is calculated numerically.
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Rotation Operator approach and spin dynamics in a time varying magnetic field
Physical Review A, 1994Co-Authors: Jinyuan Zhou, Chaohui YeAbstract:The evolution Operator for an arbitrary spin system in an arbitrary time-varying magnetic field is disentangled into the Rotation Operator; consequently, the time-ordering problem is shifted into solving the Euler geometric equations. Some realistic transformations are proposed in order to find their analytic solutions. The probabilities and phases characterizing state transitions are also analyzed.
M.n. Jipdi - One of the best experts on this subject based on the ideXlab platform.
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Rotation Operator approach for the dynamics of non dissipative multi state landau zener problems exact solutions
Physica E-low-dimensional Systems & Nanostructures, 2017Co-Authors: M.e. Ateuafack, J.t. Diffo, Lukong Cornelius Fai, M.n. JipdiAbstract:Abstract The paper investigates exact time-dependent analytical solutions of the Landau–Zener (LZ) transitions for spin one-half subjected to classical noise field using Rotation Operator approach introduced by Zhou and co-authors. The particular case of the LZ model subjected to colored noise field is studied and extended to arbitrary spin magnitude. Transition probabilities are derived regardless of the initial configuration of the system and are found to be functions of the sort for Stokes constant. It is observed that the latter may be completely evaluated provided we have knowledge of the phase difference between noise in x − and y − directions. Transition probabilities are found to depend not only on the LZ parameter and noise frequency, but also on the states involved in the study. In particular, the coherence of the system is sustained for an exceedingly long time when many levels are considered in an atom and if in addition, the LZ parameter tends to unity and the noise' frequency is low.
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Rotation Operator approach for the dynamics of non-dissipative multi-state Landau–Zener problems: Exact solutions
Physica E-low-dimensional Systems & Nanostructures, 2016Co-Authors: M.e. Ateuafack, J.t. Diffo, Lukong Cornelius Fai, M.n. JipdiAbstract:Abstract The paper investigates exact time-dependent analytical solutions of the Landau–Zener (LZ) transitions for spin one-half subjected to classical noise field using Rotation Operator approach introduced by Zhou and co-authors. The particular case of the LZ model subjected to colored noise field is studied and extended to arbitrary spin magnitude. Transition probabilities are derived regardless of the initial configuration of the system and are found to be functions of the sort for Stokes constant. It is observed that the latter may be completely evaluated provided we have knowledge of the phase difference between noise in x − and y − directions. Transition probabilities are found to depend not only on the LZ parameter and noise frequency, but also on the states involved in the study. In particular, the coherence of the system is sustained for an exceedingly long time when many levels are considered in an atom and if in addition, the LZ parameter tends to unity and the noise' frequency is low.
B C Sanctuary - One of the best experts on this subject based on the ideXlab platform.
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Rotation Operator approach to spin dynamics and the euler geometric equations
Journal of Chemical Physics, 1994Co-Authors: Jinyuan Zhou, Chaohui Ye, B C SanctuaryAbstract:The Rotation Operator approach proposed previously is applied to spin dynamics in a time‐varying magnetic field. The evolution of the wave function is described, and that of the density Operator is also treated in terms of a spherical tensor Operator base. It is shown that this formulation provides a straightforward calculation of accumulated phases and probabilities of spin transitions and coherence evolutions. The technique focuses, not on the Rotation matrix, but on the three Euler angles and its characteristic equations are equivalent to the Euler geometric equations long known to describe the motion of a rigid body. The method usually depends on numerical calculations, but analytical solutions exist in some situations. In this paper, as examples, a hyperbolic secant pulse is solved analytically, and a Gaussian‐shaped pulse is calculated numerically.
J.t. Diffo - One of the best experts on this subject based on the ideXlab platform.
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Rotation Operator approach for the dynamics of non dissipative multi state landau zener problems exact solutions
Physica E-low-dimensional Systems & Nanostructures, 2017Co-Authors: M.e. Ateuafack, J.t. Diffo, Lukong Cornelius Fai, M.n. JipdiAbstract:Abstract The paper investigates exact time-dependent analytical solutions of the Landau–Zener (LZ) transitions for spin one-half subjected to classical noise field using Rotation Operator approach introduced by Zhou and co-authors. The particular case of the LZ model subjected to colored noise field is studied and extended to arbitrary spin magnitude. Transition probabilities are derived regardless of the initial configuration of the system and are found to be functions of the sort for Stokes constant. It is observed that the latter may be completely evaluated provided we have knowledge of the phase difference between noise in x − and y − directions. Transition probabilities are found to depend not only on the LZ parameter and noise frequency, but also on the states involved in the study. In particular, the coherence of the system is sustained for an exceedingly long time when many levels are considered in an atom and if in addition, the LZ parameter tends to unity and the noise' frequency is low.
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Rotation Operator approach for the dynamics of non-dissipative multi-state Landau–Zener problems: Exact solutions
Physica E-low-dimensional Systems & Nanostructures, 2016Co-Authors: M.e. Ateuafack, J.t. Diffo, Lukong Cornelius Fai, M.n. JipdiAbstract:Abstract The paper investigates exact time-dependent analytical solutions of the Landau–Zener (LZ) transitions for spin one-half subjected to classical noise field using Rotation Operator approach introduced by Zhou and co-authors. The particular case of the LZ model subjected to colored noise field is studied and extended to arbitrary spin magnitude. Transition probabilities are derived regardless of the initial configuration of the system and are found to be functions of the sort for Stokes constant. It is observed that the latter may be completely evaluated provided we have knowledge of the phase difference between noise in x − and y − directions. Transition probabilities are found to depend not only on the LZ parameter and noise frequency, but also on the states involved in the study. In particular, the coherence of the system is sustained for an exceedingly long time when many levels are considered in an atom and if in addition, the LZ parameter tends to unity and the noise' frequency is low.
