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Angular Momentum Operator
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.

Wigner Distributions in LightFront Quark Models
FewBody Systems, 2014CoAuthors: B. Pasquini, C. LorcéAbstract:We discuss the quark Wigner distributions which represent the quantummechanical analogues of the classical phasespace 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 onebody information of partons in Momentum space. In particular, we present a study within lightfront quark models. The quark orbital Angular Momentum is also obtained from the phasespace 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 lightfront 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.

Quark orbital Angular Momentum from Wigner distributions and lightcone wave functions
Physical Review D, 2012CoAuthors: C. Lorcé, B. Pasquini, X. Xiong, F. YuanAbstract:We investigate the quark orbital Angular Momentum of the nucleon in the absence of gaugefield degrees of freedom, by using the concept of the Wigner distribution and the lightcone wave functions of the Fockstate expansion of the nucleon. The quark orbital Angular Momentum is obtained from the phasespace average of the orbital Angular Momentum Operator weighted with the Wigner distribution of unpolarized quarks in a longitudinally polarized nucleon. We also derive the lightcone wavefunction representation of the orbital Angular Momentum. In particular, we perform an expansion in the nucleon Fockstate space and decompose the orbital Angular Momentum into the Nparton state contributions. Explicit expressions are presented in terms of the lightcone wave functions of the threequark Fock state. Numerical results for the up and down quark orbital Angular momenta of the proton are shown in the lightcone constituent quark model and the lightcone chiral quarksoliton model.
F. Yuan – One of the best experts on this subject based on the ideXlab platform.

Quark orbital Angular Momentum from Wigner distributions and lightcone wave functions
Physical Review D, 2012CoAuthors: C. Lorcé, B. Pasquini, X. Xiong, F. YuanAbstract:We investigate the quark orbital Angular Momentum of the nucleon in the absence of gaugefield degrees of freedom, by using the concept of the Wigner distribution and the lightcone wave functions of the Fockstate expansion of the nucleon. The quark orbital Angular Momentum is obtained from the phasespace average of the orbital Angular Momentum Operator weighted with the Wigner distribution of unpolarized quarks in a longitudinally polarized nucleon. We also derive the lightcone wavefunction representation of the orbital Angular Momentum. In particular, we perform an expansion in the nucleon Fockstate space and decompose the orbital Angular Momentum into the Nparton state contributions. Explicit expressions are presented in terms of the lightcone wave functions of the threequark Fock state. Numerical results for the up and down quark orbital Angular momenta of the proton are shown in the lightcone constituent quark model and the lightcone chiral quarksoliton model.
John C Light – One of the best experts on this subject based on the ideXlab platform.

symmetry adapted direct product discrete variable representation for the coupled Angular Momentum Operator application to the vibrations of co2 2
Journal of Chemical Physics, 2003CoAuthors: 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 permutationinversion 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.

a grid representation for spherical angles decoupling of the Angular Momentum Operator
Journal of Chemical Physics, 1997CoAuthors: 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 φdependent and φindependent 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 wavepacket propagation (for a matrixvector product) is reduced for split exponential propagators since a direct product representation is preserved for all the angles.