Quantum properties of superpositions of oppositely squeezed states

TL;DR

This paper studies superpositions of oppositely squeezed states, revealing their unique quantum features, entanglement properties, and potential as resources for quantum information processing, with practical schemes for their generation.

Contribution

It introduces a new class of superposed squeezed states, analyzes their quantum properties, and proposes a linear-optical heralding method for their generation.

Findings

Superpositions exhibit distinct photon-number structures.

They generate higher entanglement than two-mode squeezed vacuum states.

Proposed heralding scheme enables practical state preparation.

Abstract

We investigate the quantum properties of superpositions of oppositely squeezed states, which can be regarded as Schrodinger cat states. Compared with conventional coherent-state cat states, these states exhibit distinct photon-number structures and enhanced nonclassical features. We analyze their Wigner function and quantify the entanglement generated when they are injected into a 50:50 beam splitter. For small squeezing parameters, the resulting two-mode states possess higher entanglement than pure two-mode squeezed vacuum states. We also propose a linear-optical heralding scheme that approximates this superposition of oppositely squeezed states without requiring strong Kerr nonlinearities. Our results indicate that such states are promising resources for continuous-variable quantum information processing, particularly in regimes where high non-Gaussianity and strong entanglement are desirable.