From short-time diffusive to long-time ballistic dynamics: the unusual center-of-mass motion of quantum bright solitons

TL;DR

This paper predicts and analyzes an unusual quantum phenomenon where a bright soliton's center-of-mass motion transitions from diffusive to ballistic over time due to decoherence, challenging typical diffusion expectations.

Contribution

It introduces a theoretical model showing an anomalous diffusion process in quantum bright solitons, with predictions for observable long-time ballistic behavior.

Findings

Center-of-mass motion becomes ballistic at long times

Simulations indicate the phenomenon is experimentally observable

Contrasts with typical Brownian motion behavior

Abstract

Brownian motion is ballistic on short time scales and diffusive on long time scales. Our theoretical investigations indicate that one can observe the exact opposite - an "anomaleous diffusion process" where initially diffusive motion becomes ballistic on longer time scales - in an ultracold atom system with a size comparable to macromolecules. This system is a quantum matter-wave bright soliton subject to decoherence via three-particle losses for which we investigate the center-of-mass motion. Our simulations show that such unusual center-of-mass dynamics should be observable on experimentally accessible time scales.