Nonclassical microwave radiation from the dynamical Casimir effect

TL;DR

This paper demonstrates that microwave radiation generated via the dynamical Casimir effect in superconducting circuits exhibits nonclassical properties and entanglement, providing evidence of its quantum nature despite thermal noise.

Contribution

It introduces methods to detect nonclassicality and entanglement in dynamical Casimir radiation within realistic superconducting circuits.

Findings

Radiation can be strictly nonclassical under realistic conditions

Intermode entanglement is measurable in the generated radiation

Nonclassicality indicators can confirm quantum nature experimentally

Abstract

We investigate quantum correlations in microwave radiation produced by the dynamical Casimir effect in a superconducting waveguide terminated and modulated by a superconducting quantum interference device. We apply nonclassicality tests and evaluate the entanglement for the predicted field states. For realistic circuit parameters, including thermal background noise, the results indicate that the produced radiation can be strictly nonclassical and can have a measurable amount of intermode entanglement. If measured experimentally, these nonclassicalilty indicators could give further evidence of the quantum nature of the dynamical Casimir radiation in these circuits.