Non-Hamiltonian modeling of squeezing and thermal disorder in driven oscillators

TL;DR

This paper investigates how thermal disorder affects the generation of squeezed states in driven quantum oscillators, identifying a threshold temperature relevant to biological and chemical processes.

Contribution

It introduces a non-Hamiltonian model of thermal baths influencing quantum squeezing, extending previous quadratic Hamiltonian studies to more realistic thermal environments.

Findings

Thermal disorder sets a threshold temperature for squeezing at approximately 311 K.

The model demonstrates the impact of bath representation on quantum state generation.

Threshold temperature is within biologically and chemically relevant temperature ranges.

Abstract

Recently, model systems with quadratic Hamiltonians and time-dependent interactions were studied by Briegel and Popescu and by Galve et al. in order to consider the possibility of both quantum refrigeration in enzymes [Proc. R. Soc. 469 20110290 (2013)] and entanglement in the high temperature limit [Phys. Rev. Lett. 105 180501 (2010); Phys. Rev. A 81 062117 (2010)]. Following this line of research, we studied a model comprising two quantum harmonic oscillators driven by a time-dependent harmonic coupling. Such a system was embedded in a thermal bath represented in two different ways. In one case, the bath was composed of a finite but great number of independent harmonic oscillators with an Ohmic spectral density. In the other case, the bath was more efficiently defined in terms of a single oscillator coupled to a non-Hamiltonian thermostat. In both cases, we simulated the effect of the thermal disorder on the generation of the squeezed states in the two-oscillators relevant system. We found that, in our model, the thermal disorder of the bath determines the presence of a threshold temperature, for the generation of squeezed states, equal to T=311.13 K. Such a threshold is estimated to be within temperatures where chemical reactions and biological activity comfortably take place.