Energy Transfer Using Unitary Transformations

Entropy

Winny O’Kelly de Galway¹ 

[1] Institute for Theoretical Physics, KU Leuven, Leuven B-3001, Belgium; E-Mail:

关键词: quantum stirring;    S-matrix;    driven quantum system;    three-level system;   

DOI  :  10.3390/e15125121

来源: mdpi

【 摘 要 】

We study the unitary time evolution of a simple quantum Hamiltonian describing two harmonic oscillators coupled via a three-level system. The latter acts as an engine transferring energy from one oscillator to the other and is driven in a cyclic manner by time-dependent external fields. The S-matrix (scattering matrix) of the cycle is obtained in analytic form. The total number of quanta contained in the system is a conserved quantity. As a consequence, the spectrum of the S-matrix is purely discrete, and the evolution of the system is quasi-periodic. The explicit knowledge of the S-matrix makes it possible to do accurate numerical evaluations of the time-dependent wave function. They confirm the quasi-periodic behavior. In particular, the energy flows back and forth between the two oscillators in a quasi-periodic manner.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.