Quantum Flutter: Signatures and Robustness

Michael Knap,Eugene Demler,Martin Ganahl,Mikhail B Zvonarev,Charles J M Mathy

doi:10.1103/physrevlett.112.015302

Abstract

We investigate the motion of an impurity particle injected with finite velocity into an interacting one-dimensional quantum gas. Using large-scale numerical simulations based on matrix product states, we observe and quantitatively analyze long-lived oscillations of the impurity momentum around a nonzero saturation value, called quantum flutter. We show that the quantum flutter frequency is equal to the energy difference between two branches of collective excitations of the model. We propose an explanation of the finite saturation momentum of the impurity based on the properties of the edge of the excitation spectrum. Our results indicate that quantum flutter exists away from integrability and provide parameter regions in which it could be observed in experiments with ultracold atoms using currently available technology.

Highlights

Quantum flutter was demonstrated by examining the full quantummechanical evolution of the impurity state, obtained from the exact Bethe Ansatz solution, which exploits the integrability of the model
In this Letter, we report numerical evidence of quantum flutter in the dynamics of an impurity with arbitrary mass injected into a 1D quantum gas of interacting bosons, see Fig. 1
Bethe Ansatz calculations of Ref. [34] and time-evolving block decimation (TEBD) simulations reported in this Letter indicate that the amplitude of the oscillations in the impurity momentum slowly decays with increasing time

Summary

Introduction

Using large-scale numerical simulations based on matrix product states, we observe and quantitatively analyze long-lived oscillations of the impurity momentum around a non-zero saturation value, called quantum flutter. Quantum flutter was demonstrated by examining the full quantummechanical evolution of the impurity state, obtained from the exact Bethe Ansatz solution, which exploits the integrability of the model.

Results

Conclusion