Coherent State Formulation of Damped Systems

W. H. Louisell, John H. Marburger

The quantum theory of damping is presented and illustrated by means of a driven damped harmonic oscillator. The theory is formulated in the coherent state representation which illustrates very vividly the nearly classical nature of the problem. In this representation the reduced system density operator equation becomes a Fokker-Planck equation. Green's function solutions are found for the damped oscillator in closed form and as an eigenfunction expansion. In addition, a quantum regression theorem due to Lax is derived in the coherent state representation. The theorem allows two-time averages to be computed from one-time averages.

Subir Kumar Bose, U. B. Dubey, V. N. Tewari

Ravinder Rupchand Puri

Sergey S. Safonov

The quadrature distribution for a quantum damped oscillator is introduced in the frame of formulation of quantum mechanics based on a tomography scheme. The probability distribution for coherent and Fock states of the damped oscillator is expressed explicitly in terms of Gaussian and Hermite polynomials, respectively.

Mustafa Dernek, Nuri Ünal

In this study, first we construct the quasi-coherent states for a damped and forced harmonic oscillator and discuss the transition of the system from the damped oscillations to forced steady state oscillations. Second, we generalize the Caldirola-Kanai Hamiltonian into the new systems such as the frequency and the mass parameters are time dependent and discuss three examples of them.

B. Rémaud, Claudio Oscar Dorso, E. Susana Hernández