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

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.

5 pages + appendix, one figure

References in corpus (22)

• Generation of a superposition of odd photon number states for quantum information networks
• Remote creation of hybrid entanglement between particle-like and wave-like optical qubits
• Entangling quantum and classical states of light
• Macroscopicity of Mechanical Quantum Superposition States
• Measures of macroscopicity for quantum spin systems
• Quantification of Macroscopic Quantum Superpositions within Phase Space
• A measurement-based measure of the size of macroscopic quantum superpositions
• Experimental continuous-variable entanglement from a phase-difference-locked optical parametric oscillator
• Measuring the size of a Schroedinger cat state
• Signatures for generalized macroscopic superpositions
• The size of quantum superpositions as measured with "classical" detectors
• How difficult it is to prove the quantumness of macroscropic states?
• Linking Measures for Macroscopic Quantum States via Photon-Spin Mapping
• Characterizations and Quantifications of Macroscopic Quantumness and Its Implementations using Optical Fields
• Experimental demonstration of frequency-degenerate bright EPR beams with a self-phase-locked optical parametric oscillator
• Tighter quantum uncertainty relations follow from a general probabilistic bound
• Criteria for generalized macroscopic and mesoscopic quantum coherence
• Quantum Fisher Information as the Convex Roof of Variance
• Classification of macroscopic quantum effects
• Assessments of macroscopicity for quantum optical states
• Measurement- and comparison-based sizes of Schrödinger cat states of light
• Are cloned quantum states macroscopic?

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