The Experts below are selected from a list of 4029 Experts worldwide ranked by ideXlab platform
C. Lorcé - One of the best experts on this subject based on the ideXlab platform.
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Wigner Distributions in Light-Front Quark Models
Few-Body Systems, 2014Co-Authors: B. Pasquini, C. LorcéAbstract:We discuss the quark Wigner distributions which represent the quantum-mechanical analogues of the classical phase-space distributions. These functions can be obtained through a Fourier transform in the transverse space of the generalized transverse Momentum dependent parton distributions, which encode the most general one-body information of partons in Momentum space. In particular, we present a study within light-front quark models. The quark orbital Angular Momentum is also obtained from the phase-space average of the orbital Angular Momentum Operator weighted with the Wigner distribution of unpolarized quark in a longitudinally polarized nucleon. The corresponding results calculated within different light-front quark models are compared with alternative definitions of the quark orbital Angular Momentum as given in terms of generalized parton distributions and transverse Momentum dependent parton distributions.
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Quark orbital Angular Momentum from Wigner distributions and light-cone wave functions
Physical Review D, 2012Co-Authors: C. Lorcé, B. Pasquini, X. Xiong, F. YuanAbstract:We investigate the quark orbital Angular Momentum of the nucleon in the absence of gauge-field degrees of freedom, by using the concept of the Wigner distribution and the light-cone wave functions of the Fock-state expansion of the nucleon. The quark orbital Angular Momentum is obtained from the phase-space average of the orbital Angular Momentum Operator weighted with the Wigner distribution of unpolarized quarks in a longitudinally polarized nucleon. We also derive the light-cone wave-function representation of the orbital Angular Momentum. In particular, we perform an expansion in the nucleon Fock-state space and decompose the orbital Angular Momentum into the N-parton state contributions. Explicit expressions are presented in terms of the light-cone wave functions of the three-quark Fock state. Numerical results for the up and down quark orbital Angular momenta of the proton are shown in the light-cone constituent quark model and the light-cone chiral quark-soliton model.
F. Yuan - One of the best experts on this subject based on the ideXlab platform.
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Quark orbital Angular Momentum from Wigner distributions and light-cone wave functions
Physical Review D, 2012Co-Authors: C. Lorcé, B. Pasquini, X. Xiong, F. YuanAbstract:We investigate the quark orbital Angular Momentum of the nucleon in the absence of gauge-field degrees of freedom, by using the concept of the Wigner distribution and the light-cone wave functions of the Fock-state expansion of the nucleon. The quark orbital Angular Momentum is obtained from the phase-space average of the orbital Angular Momentum Operator weighted with the Wigner distribution of unpolarized quarks in a longitudinally polarized nucleon. We also derive the light-cone wave-function representation of the orbital Angular Momentum. In particular, we perform an expansion in the nucleon Fock-state space and decompose the orbital Angular Momentum into the N-parton state contributions. Explicit expressions are presented in terms of the light-cone wave functions of the three-quark Fock state. Numerical results for the up and down quark orbital Angular momenta of the proton are shown in the light-cone constituent quark model and the light-cone chiral quark-soliton model.
John C Light - One of the best experts on this subject based on the ideXlab platform.
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symmetry adapted direct product discrete variable representation for the coupled Angular Momentum Operator application to the vibrations of co2 2
Journal of Chemical Physics, 2003Co-Authors: H S Lee, Hua Chen, John C LightAbstract:The theoretical (quantum) description of large amplitude vibrations of systems containing four or more atoms using orthogonal internal coordinates requires three or more Angular coordinates. The basis commonly used to represent these coordinates is the coupled Angular Momentum basis. We show that a direct product Angular discrete variable representation (DVR) can be used advantageously, particularly for systems with high permutation-inversion symmetry and nonlinear equilibrium geometry. The DVR permits full symmetry projection and solution by the sequential diagonalization and truncation method. Application to the dimer of rigid CO2 demonstrates the accuracy and efficiency of the approach.
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a grid representation for spherical angles decoupling of the Angular Momentum Operator
Journal of Chemical Physics, 1997Co-Authors: Jiqiong Dai, John C LightAbstract:The Angular Momentum Operator which is a function of the orientational angle θ and the azimuthal angle φ may be split into the φ-dependent and φ-independent parts so that the split exponential Operator method can be exactly implemented (with orthogonal transformations) in a direct product discrete variable representation of θ and φ. Although one loses the exact representation of the Angular Momentum in the spherical harmonic basis, the direct product representations have been proved to converge and to be stable and efficient. An advantage is that computational time for a wave-packet propagation (for a matrix-vector product) is reduced for split exponential propagators since a direct product representation is preserved for all the angles.
Luca Salasnich - One of the best experts on this subject based on the ideXlab platform.
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on the convergence of the wkb series for the Angular Momentum Operator
Journal of Physics A, 1997Co-Authors: Luca Salasnich, Fabio SattinAbstract:In this paper we prove a recent conjecture about the convergence of the WKB series for the Angular Momentum Operator. We demonstrate that the WKB algorithm for the Angular Momentum gives the exact quantization formula if all orders are summed. Finally, we discuss the supersymmetric semiclassical quantum mechanics (SWKB), which gives the correct quantization of the Angular Momentum at the leading order.
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On the Convergence of the WKB Series for the Angular Momentum Operator
Journal of Physics A: Mathematical and General, 1997Co-Authors: Luca Salasnich, Fabio SattinAbstract:In this paper we prove a recent conjecture [Robnik M and Salasnich L 1997 J. Phys. A: Math. Gen. 30 1719] about the convergence of the WKB series for the Angular Momentum Operator. We demonstrate that the WKB algorithm for the Angular Momentum gives the exact quantization formula if all orders are summed.
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SWKB for the Angular Momentum
Modern Physics Letters B, 1997Co-Authors: Luca Salasnich, Fabio SattinAbstract:In this paper we solve the eigenvalue problem of the Angular Momentum Operator by using the supersymmetric semiclassical quantum mechanics (SWKB), and show that it gives the correct quantization already at the leading order.
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Semiclassical Expansion for the Angular Momentum
arXiv: Nuclear Theory, 1996Co-Authors: Marko Robnik, Luca SalasnichAbstract:After reviewing the WKB series for the Schr\"odinger equation we calculate the semiclassical expansion for the eigenvalues of the Angular Momentum Operator. This is the first systematic semiclassical treatment of the Angular Momentum for terms beyond the leading torus approximation.
B. Pasquini - One of the best experts on this subject based on the ideXlab platform.
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Wigner Distributions in Light-Front Quark Models
Few-Body Systems, 2014Co-Authors: B. Pasquini, C. LorcéAbstract:We discuss the quark Wigner distributions which represent the quantum-mechanical analogues of the classical phase-space distributions. These functions can be obtained through a Fourier transform in the transverse space of the generalized transverse Momentum dependent parton distributions, which encode the most general one-body information of partons in Momentum space. In particular, we present a study within light-front quark models. The quark orbital Angular Momentum is also obtained from the phase-space average of the orbital Angular Momentum Operator weighted with the Wigner distribution of unpolarized quark in a longitudinally polarized nucleon. The corresponding results calculated within different light-front quark models are compared with alternative definitions of the quark orbital Angular Momentum as given in terms of generalized parton distributions and transverse Momentum dependent parton distributions.
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Quark orbital Angular Momentum from Wigner distributions and light-cone wave functions
Physical Review D, 2012Co-Authors: C. Lorcé, B. Pasquini, X. Xiong, F. YuanAbstract:We investigate the quark orbital Angular Momentum of the nucleon in the absence of gauge-field degrees of freedom, by using the concept of the Wigner distribution and the light-cone wave functions of the Fock-state expansion of the nucleon. The quark orbital Angular Momentum is obtained from the phase-space average of the orbital Angular Momentum Operator weighted with the Wigner distribution of unpolarized quarks in a longitudinally polarized nucleon. We also derive the light-cone wave-function representation of the orbital Angular Momentum. In particular, we perform an expansion in the nucleon Fock-state space and decompose the orbital Angular Momentum into the N-parton state contributions. Explicit expressions are presented in terms of the light-cone wave functions of the three-quark Fock state. Numerical results for the up and down quark orbital Angular momenta of the proton are shown in the light-cone constituent quark model and the light-cone chiral quark-soliton model.