Pure state condition for the semi-classical Wigner function |
| |
Authors: | A M Ozorio de Almeida |
| |
Institution: | Instituto de Física “Gleb Wataghin” Universidade Estadual de Campinas, Campinas, 13100 SP., Brasil |
| |
Abstract: | The Wigner function W(p,q) is a symmetrized Fourier transform of the density matrix ρ(q1,q2), representing quantum-mechanical states or their statistical mixture in phase space. Identification of these two alternatives in the case of density matrices depends on the projection identity ρ2 = ρ; its Wigner correspondence is the pure state condition. This criterion is applied to the Wigner functions obtained from standard semiclassical wave functions, determining as pure states those whose classical invariant tori satisfy the generalized Bohr-Sommerfeld conditions. Superpositions of eigenstates are then examined and it is found that the Wigner function corresponding to Gaussian random wave functions are smoothed out in the manner of mixed-state Wigner functions. Attention is also given to the pure-state condition in the case where an angular coordinate is used. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|