Controlling quantum interference in phase space with amplitude

Yinghong Xue,Katsuyuki Kasai,Masayoshi Watanabe,Yun Zhang,Tingyu Li,Yoshiko Okada-Shudo

doi:10.1038/s41598-017-02540-3

Abstract

We experimentally show a quantum interference in phase space by interrogating photon number probabilities (n = 2, 3, and 4) of a displaced squeezed state, which is generated by an optical parametric amplifier and whose displacement is controlled by amplitude of injected coherent light. It is found that the probabilities exhibit oscillations of interference effect depending upon the amplitude of the controlling light field. This phenomenon is attributed to quantum interference in phase space and indicates the capability of controlling quantum interference using amplitude. This remarkably contrasts with the oscillations of interference effects being usually controlled by relative phase in classical optics.

Highlights

In quantum optics, the optical phase space is a useful tool in which all quantum states of an optical system can be represented
The quantum interference in phase space is an essential concept and it gives a convincing interpretation for many quantum phenomena in modern physics[6]
Most of experimental achievements were mainly focused on the presentations of different quantum state in phase space, such as squeezed state, single-photon state, Schödinger cat state and so on[9,10,11,12,13]

Summary

Introduction

The optical phase space is a useful tool in which all quantum states of an optical system can be represented. We found that oscillations of interference in phase space can be controlled by amplitude of field, contrasting to that these oscillations are usually controlled by relative phase both in classical and quantum physics The observation of this phenomenon was proposed by interfering two arbitrary number states on a beam splitter with variable transmission and reflection coefficients[19]. The demonstration was implemented by a displaced squeezed state (DSS), which is generated by displacing a squeezed vacuum state in the phase space We consider the displacement on the direction of x, i.e. α is a positive real number

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