Analytical study of a finite-range impurity in a one-dimensional Bose gas

Fuente: arXiv
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Main Authors: Yoğurt, T. Alper, Eiles, Matthew T.
Format: Preprint
Published: 2025
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author Yoğurt, T. Alper
Eiles, Matthew T.
author_facet Yoğurt, T. Alper
Eiles, Matthew T.
contents One-dimensional Bose gases present an interesting setting to study the physics of Bose polarons, as density fluctuations play an enhanced role due to reduced dimensionality. Theoretical descriptions of this system have predominantly relied on contact pseudopotentials to model the impurity-bath interaction, leading to unphysical results in the strongly coupled limit. In this work, we analytically solve the Gross-Pitaevskii equation, using a square well potential instead of a zero-range potential, for the ground-state wave function of a static impurity. We compute perturbative corrections arising from infinitesimally slow impurity motion. The polaron energy and effective mass remain finite in the strongly coupled regime, in contrast to the divergent behavior obtained using a contact potential. In this limit, we characterize the polaron properties in terms of the dimensionless ratio $\bar{w}\equiv w/ξ$ between the interaction range $w$ of the impurity-bath potential and the coherence length $ξ$ of the Bose gas. The effective mass exhibits a $1/\bar{w}$ scaling. The energy of the attractive polaron scales as $-1/\bar{w}^3$, whereas the repulsive polaron features subleading corrections to the dark soliton energy at the order $\bar{w}^3$.
format Preprint
id arxiv_https___arxiv_org_abs_2508_11394
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Analytical study of a finite-range impurity in a one-dimensional Bose gas
Yoğurt, T. Alper
Eiles, Matthew T.
Quantum Gases
Atomic Physics
One-dimensional Bose gases present an interesting setting to study the physics of Bose polarons, as density fluctuations play an enhanced role due to reduced dimensionality. Theoretical descriptions of this system have predominantly relied on contact pseudopotentials to model the impurity-bath interaction, leading to unphysical results in the strongly coupled limit. In this work, we analytically solve the Gross-Pitaevskii equation, using a square well potential instead of a zero-range potential, for the ground-state wave function of a static impurity. We compute perturbative corrections arising from infinitesimally slow impurity motion. The polaron energy and effective mass remain finite in the strongly coupled regime, in contrast to the divergent behavior obtained using a contact potential. In this limit, we characterize the polaron properties in terms of the dimensionless ratio $\bar{w}\equiv w/ξ$ between the interaction range $w$ of the impurity-bath potential and the coherence length $ξ$ of the Bose gas. The effective mass exhibits a $1/\bar{w}$ scaling. The energy of the attractive polaron scales as $-1/\bar{w}^3$, whereas the repulsive polaron features subleading corrections to the dark soliton energy at the order $\bar{w}^3$.
title Analytical study of a finite-range impurity in a one-dimensional Bose gas
topic Quantum Gases
Atomic Physics
url https://arxiv.org/abs/2508.11394