Four-wave mixing with anti-parity-time symmetry in hot $^{85}$Rb vapor

TL;DR

This paper demonstrates anti-parity-time symmetric four-wave mixing in hot rubidium vapor, exploring quantum correlations near exceptional points, with experimental results aligning with theoretical models.

Contribution

First experimental realization of anti-PT symmetric four-wave mixing in thermal vapor, analyzing quantum correlations with noise considerations.

Findings

Measured classical four-wave mixing gain

Observed two-mode relative-intensity squeezing

Results agree with theoretical predictions

Abstract

We report an experimental demonstration of anti-parity-time (anti-PT) symmetric optical four-wave mixing in thermal Rubidium vapor, where the propagation of two conjugate optical fields in a double-$\Lambda$ scheme is governed by a non-Hermitian Hamiltonian. We are particularly interested in studying quantum intensity correlations between the two conjugate fields near the exceptional point, taking into account loss and accompanied Langevin noise. Our experimental measurements of classical four-wave mixing gain and the associated two-mode relative-intensity squeezing are in reasonable agreement with the theoretical predictions.