Generation of large-amplitude coherent-state superposition via ancilla-assisted photon-subtraction

TL;DR

This paper introduces a new method for generating large-amplitude coherent-state superpositions using ancilla-assisted photon subtraction, enhancing control and achieving record sizes for quantum information applications.

Contribution

The paper presents a novel ancilla-assisted photon-subtraction technique that significantly increases the size and controllability of coherent-state superpositions.

Findings

Largest CSS reported without corrections

Successful demonstration with time-separated two-photon subtraction

Enhanced quantum superposition controllability

Abstract

We propose and demonstrate a novel method to generate a large-amplitude coherent-state superposition (CSS) via ancilla-assisted photon-subtraction. The ancillary mode induces quantum interference of indistinguishable processes, widening the controllability of quantum superposition at the conditional output. We demonstrate the concept in the time domain, by a simple time-separated two-photon subtraction from cw squeezed light. We observe the largest CSS ever reported without any corrections, which will enable various quantum information applications with CSS states.