Controlling the nonclassical properties of a hybrid Cooper pair box system and an intensity dependent nanomechanical resonator

TL;DR

This paper investigates the quantum properties of a hybrid system combining a nanomechanical resonator and a Cooper pair box, analyzing entropy and excitation-inversion dynamics with realistic considerations like losses and time-dependent parameters.

Contribution

It introduces a detailed model using the Buck-Sukumar approach to study nonclassical properties in a realistic, lossy hybrid quantum system with time-dependent features.

Findings

Entropy and excitation-inversion are sensitive to losses and time-dependent parameters.

Proper parameter choices can control nonclassical states and quantum features.

The system's behavior suggests potential applications in quantum technologies.

Abstract

We employ a more realistic treatment to investigate the entropy and the excitation-inversion of a coupled system that consists of a nanomechanical resonator and a superconducting Cooper pair box. The procedure uses the Buck-Sukumar model in the microwave domain, considers the nanoresonator with a time dependent frequency and both subsystems in the presence of losses. Interesting results were found for the temporal evolutions of the entropy of each subsystem and of the excitation-inversion in the Cooper pair box. A comparison was also performed about which of these two subsystems is more sensitive to the presence of losses. The results suggest that appropriate choices of the involved time dependent parameters allow us to monitor these two features of the subsystems and may offer potential applications, e.g., in the generation of nonclassical states, quantum communication, quantum lithography.