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arXiv · 2511.03204

Application and quantum properties of superpositions of oppositely squeezed states

Hiroo Azuma·William J. Munro·Kae Nemoto
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Abstract

We show that superpositions of oppositely squeezed states -- non-Gaussian Schr{\"{o}}dinger-cat-like states -- exhibit enhanced nonclassical features and provide an entanglement advantage in the small-squeezing regime. These states possess photon-number structures distinct from conventional coherent-state cat states, and we analyze their Wigner functions and the entanglement generated when they are injected into a 50-50 beam splitter. As a practical application, we demonstrate that they enable a high-quality heralded single-photon source whose second-order intensity correlation function is smaller than that obtained from a pure two-mode squeezed vacuum state. We further propose a linear-optical heralding scheme that approximates these superpositions without requiring strong Kerr nonlinearities. Our results indicate that the superposition of oppositely squeezed states is a promising non-Gaussian resource for quantum information processing, particularly for single-photon generation.

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Hiroo Azuma, William J. Munro, Kae Nemoto. 2025-11-05. Application and quantum properties of superpositions of oppositely squeezed states. https://doi.org/10.1103/dhq3-wcd7

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