Reading, writing and squeezing the entangled states of two nanomechanical resonators coupled to a SQUID

TL;DR

This paper explores entanglement, state manipulation, and noise reduction in two nanomechanical resonators coupled to a SQUID, proposing methods for reading, writing, and squeezing their quantum states with analysis of dissipation effects.

Contribution

It introduces a scheme to entangle, read, write, and squeeze the states of two nanomechanical resonators coupled to a SQUID, including dissipation effects.

Findings

Resonators can be used as entangled quantum memory elements.

A scheme for squeezing the resonators' even mode reduces measurement noise.

Dissipation impacts squeezing differently in weak and strong damping regimes.

Abstract

We study a system of two nanomechanical resonators embedded in a dc SQUID. We show that the inductively-coupled resonators can be treated as two entangled quantum memory elements with states that can be read from, or written on by employing the SQUID as a displacement detector or switching additional external magnetic fields, respectively. We present a scheme to squeeze the even modeof the state of the resonators and consequently reduce the noise in the measurement of the magnetic flux threading the SQUID. Wefinally analyze the effect of dissipation on the squeezing using the quantum master equation, and show the qualitatively differentbehavior for the weak and strong damping regimes. Our predictions can be tested using current experimental capabilities.