Wigner negativity in the steady-state output of a Kerr parametric oscillator

TL;DR

This paper investigates how the steady-state output of a driven Kerr parametric oscillator can display nonclassical Wigner negativity in specific wave packet modes, despite the intracavity field being classical.

Contribution

It introduces a new numerical method to analyze the density matrix of arbitrary wave packet modes and reveals Wigner negativity in the output field.

Findings

Output field can exhibit Wigner negativity even when the intracavity field is positive.

The mode-dependent properties influence the nonclassical features of the output.

A novel numerical approach enables detailed analysis of wave packet modes.

Abstract

The output field from a continuously driven linear parametric oscillator may exhibit considerably more squeezing than the intracavity field. Inspired by this fact, we explore the nonclassical features of the steady-state output field of a driven nonlinear Kerr parametric oscillator using a temporal wave packet mode description. Utilizing a new numerical method, we have access to the density matrix of arbitrary wave packet modes. Remarkably, we find that even though the steady-state cavity field is always characterized by a positive Wigner function, the output may exhibit Wigner negativity, depending on the properties of the selected mode.