Superposition of two-mode squeezed states for quantum information processing and quantum sensing

TL;DR

This paper explores superpositions of two-mode squeezed states, demonstrating their enhanced entanglement and potential for high-precision quantum sensing through phase-space displacement measurements.

Contribution

It introduces a method to generate superpositions of TMSSs and shows their advantages for quantum information and sensing applications.

Findings

Superpositions of TMSSs can have higher entanglement than individual TMSSs.

Reduced single-mode states from superpositions can be used for precise displacement sensing.

The Wigner function exhibits a narrower peak with increasing photon number, improving sensing accuracy.

Abstract

We investigate superpositions of two-mode squeezed states (TMSSs), which have potential applications to quantum information processing and quantum sensing. Firstly we study some properties of these nonclassical states such as the statistics of each mode and the degree of entanglement between the two modes, which can be higher than that of a TMSS with the same degree of squeezing. The states we consider can be prepared by inducing two-mode Jaynes-Cummings and anti-Jaynes-Cummings interactions in a system of two modes and a spin-$\tfrac{1}{2}$ particle, for instance in the trapped ion domain, as described here. We show that when two harmonic oscillators are prepared in a superposition of two TMSSs, each reduced single-mode state can be advantageously employed to sense arbitrary displacements of the mode in phase space. The Wigner function of this reduced state exhibits a symmetrical peak centered at the phase-space origin, which has the convenient peculiarity of getting narrower in both quadratures simultaneously as the average photon number increases. This narrow peakcan be used as the pointer of our quantum sensor, with its position in phase space indicating the displacement undergone by the oscillator.