Two-mode squeezed states as Schrodinger-cat-like states

TL;DR

This paper explores two-mode squeezed states as macroscopic superpositions similar to Schrödinger cat states, extending criteria for identifying such states and evaluating their potential in quantum metrology.

Contribution

It introduces a framework to identify macroscopic superpositions in continuous variable entangled states, specifically applying it to two-mode squeezed states and comparing experimental results.

Findings

Two-mode squeezed vacuum states are classified as Schrödinger-cat-like states.

Extended criteria effectively identify macroscopic superpositions in continuous variables.

Results suggest potential for quantum metrology applications.

Abstract

In recent years, there has been an increased interest in the generation of superposition of coherent states with opposite phases, the so-called photonic Schrodinger-cat states. These experiments are very challenging and so far, cats involving small photon numbers only have been implemented. Here, we propose to consider two-mode squeezed states as examples of a Schrodinger-cat-like state. In particular, we are interested in several criteria aiming to identify quantum states that are macroscopic superpositions in a more general sense. We show how these criteria can be extended to continuous variable entangled states. We apply them to various squeezed states, argue that two-mode squeezed vacuum states belong to a class of general Schrodinger-cat states and compare the size of states obtained in several experiments. Our results not only promote two-mode squeezed states for exploring quantum effects at the macroscopic level but also provide direct measures to evaluate their usefulness for quantum metrology.