Generating photon-added states without adding a photon

TL;DR

This paper presents a method to generate a variety of nonclassical light states, including photon-added states, through conditional measurements on an optical parametric amplifier without adding photons to the modes.

Contribution

The authors demonstrate a novel approach to produce a continuous range of nonclassical states, including photon-added states, without photon addition during amplification.

Findings

Can generate a broad spectrum of nonclassical states by varying amplifier gain

Photon-added states produced without actual photon addition during amplification

Method has potential applications in quantum information processing

Abstract

We show that a continuous range of nonclassical states of light can be generated using conditional measurements on the idler mode of an optical parametric amplifier. The output state is prepared by introducing a coherent state in the signal mode of the amplifier with a single photon in the idler mode, followed by a conditional measurement of a single photon in the output idler mode. By varying the gain of the amplifier, this approach can produce a coherent state, a photon-added state, a displaced number state, or a continuous range of other nonclassical states with intermediate properties. We note that this approach can generate a photon-added state even though the post-selected amplifier does not add any photons to the signal or idler modes. The ability to generate a continuous range of nonclassical states may have practical applications in quantum information processing.