Estudos semiclassicos na representação de estados coerentes
AUTOR(ES)
Ademir Luiz Xavier Jr
DATA DE PUBLICAÇÃO
1997
RESUMO
In this work we develop and apply a semiclassical approximation to the coherent-state propagator K(z",z ,t) = (z"iHt/h)z ), where H is the Hamilton operator for the suystem and z) represents the coherent states of the harmonic oscilator. The semiclassical K(z",z ,t) makes use of a stationary phase approxiamtion in which stationary trajectories inhabit is studied for general quadratic 1-d Hamiltonians, the particle-in-a-box and an example of non-linear system, the quartic oscillator. By comparing with a full quantum calculation, the accuracy of the semiclassical approximation is confirmed for each one of these cases. Finally the process of scattering through a potential square barrier is successfully treated, a situation for whick no ordinary semiclassical method based entirely upon classical (real) trajectories cam account for in the ünderbarrier"energy regime. An extension of the classical traversal time concept to the complex space enable us to calculate the traversal time for the quantum particle represented by a coherent state wave packet whose initial average energy is below the barrier top. We propose such quantum traversal time as a sensible candidate for the coherent-state tunneling time in phase-space
ASSUNTO(S)
otica quantica funções de kernel funções de variaveis complexas
