Cooper Pair Boxes Weakly Coupled to External Environments

TL;DR

This paper investigates how environmental noise affects charge oscillations in superconducting Cooper Pair Boxes, revealing that quantum and semiclassical interpretations differ in stability, with quantum states being more fragile.

Contribution

It provides a comparative analysis of quantum and semiclassical models, highlighting the differing stability properties of charge oscillations under environmental influence.

Findings

Quantum occupation number states are more unstable than semiclassical coherent states.

Environmental noise destabilizes quantum interpretations more significantly.

Semiclassical models exhibit greater robustness against dissipation.

Abstract

We study the behaviour of charge oscillations in Superconducting Cooper Pair Boxes weakly interacting with an environment. We found that, due to the noise and dissipation induced by the environment, the stability properties of these nanodevices differ according to whether the charge oscillations are interpreted as an effect of macroscopic quantum coherence, or semiclassically in terms of the Gross-Pitaevskii equation. More specifically, occupation number states, used in the quantum interpretation of the oscillations, are found to be much more unstable than coherent ones, typical of the semiclassical explanation.