Quantum Decay of an Optical Soliton

TL;DR

This paper demonstrates that quantum effects cause optical solitons, initially stable classically, to decay by shedding photons, with decay rate influenced by higher-order interactions and characterized by a specific power spectrum.

Contribution

It reveals quantum-induced decay of optical solitons beyond the linear approximation, incorporating higher-order interactions and analyzing the resulting photon emission spectrum.

Findings

Quantum effects cause soliton decay over time.

Higher-order interactions lead to photon number decrease.

Power spectrum shows a narrow band near initial soliton momentum.

Abstract

Optical solitons are known to be classically stable objects which are robust to perturbations. In this work, we show that due to quantum mechanical effects, an optical soliton that is initially in a classical soliton coherent state will shed photons into the continuum and hence decay. The standard formulation of the quantized soliton uses the linearized version of the quantum nonlinear Schrodinger equation in the background of the classical soliton, and the quantized soliton remains stable in this approximation. We show that if higher-order interaction terms are taken into account, the soliton is no longer stable, and its photon number decreases quadratically as a function of the number of soliton cycles. We compute the power spectrum for the continuum radiation and find a narrow band that is localized about the initial soliton momentum with a cut-off that is inversely proportional to the initial soliton width.