Linear response of one-dimensional liquid $^4$He to external perturbations

TL;DR

This paper investigates the linear response of one-dimensional liquid helium-4 to external disturbances using ab-initio calculated dynamical structure factors, focusing on impurity drag force and density response functions.

Contribution

It provides a detailed analysis of the response functions of 1D liquid helium-4 based on recent ab-initio data, offering new insights into its dynamical behavior.

Findings

Calculated drag force for impurities at various velocities

Determined static response function $hi(q)$ for density modulations

Analyzed the system's response to different perturbation wave vectors

Abstract

We study the response of one-dimensional liquid $^4$He to weak perturbations relying on the dynamical structure factor, $S(q,\omega)$, recently obtained via ab-initio techniques [Phys. Rev. Lett. 116, 135302 (2016)]. We evaluate the drag force, $F_v$, experienced by an impurity moving along the system with velocity $v$ and the static response function, $\chi(q)$, describing the density modulations induced by a periodic perturbation with wave vector $q$.