Classical-to-quantum transition in multimode nonlinear systems with strong photon-photon coupling

TL;DR

This paper investigates the transition from classical to quantum behavior in multimode nonlinear photonic systems with strong photon-photon coupling, using a quantum cluster-expansion method to analyze quantum effects in second harmonic generation.

Contribution

It introduces a quantum cluster-expansion approach to efficiently study quantum dynamics in multimode nonlinear photonic systems, surpassing mean-field limitations.

Findings

Reveals quantum behaviors of optical parametric oscillations near threshold

Provides a universal tool for analyzing quantum dynamics in multimode systems

Enables exploration of nonlinear photonic devices for quantum information processing

Abstract

With advanced micro- and nano-photonic structures, the vacuum photon-photon coupling rate is anticipated to approach the intrinsic loss rate and lead to unconventional quantum effects. Here, we investigate the classical-to-quantum transition of such photonic nonlinear systems using the quantum cluster-expansion method, which addresses the computational challenge in tracking large photon number states of the fundamental and harmonic optical fields involved in the second harmonic generation process. Compared to the mean-field approximation used in weak coupling limit, the quantum cluster-expansion method solves multimode dynamics efficiently and reveals the quantum behaviors of optical parametric oscillations around the threshold. This work presents a universal tool to study quantum dynamics of multimode systems and explore the nonlinear photonic devices for continuous-variable quantum information processing.