Exploring a new regime for processing optical qubits: squeezing and unsqueezing single photons

TL;DR

This paper demonstrates a reliable squeezing gate acting on non-Gaussian optical states, enabling reversible conversion between single photons and superpositions of coherent states, advancing hybrid quantum information processing.

Contribution

The first implementation of a deterministic, reversible squeezing operation on non-Gaussian states, bridging discrete and continuous quantum protocols.

Findings

Successful two-way conversion between single-photon and coherent superposition states

Preservation of Wigner function negativities during squeezing

Advancement towards hybrid quantum information processing

Abstract

We implement the squeezing operation as a genuine quantum gate, deterministically and reversibly acting `online' upon an input state no longer restricted to the set of Gaussian states. More specifically, by applying an efficient and robust squeezing operation for the first time to non-Gaussian states, we demonstrate a two-way conversion between a particle-like single-photon state and a wave-like superposition of coherent states. Our squeezing gate is reliable enough to preserve the negativities of the corresponding Wigner functions. This demonstration represents an important and necessary step towards hybridizing discrete and continuous quantum protocols.