Static density response of one-dimensional soft bosons across the clustering transition

TL;DR

This paper studies how one-dimensional soft bosons respond to density perturbations across a clustering transition, revealing the emergence of density modulations and the nature of the phase change at zero temperature.

Contribution

It provides the first detailed analysis of the static density response function in a quantum one-dimensional soft boson system across the clustering transition.

Findings

Response function peaks at clustering wavevector

Density modulations increase near transition

Quantum Monte Carlo accurately captures response behavior

Abstract

One-dimensional bosons interacting via a soft-shoulder potential are investigated at zero temperature. The flatness of the potential at short distances introduces a typical length, such that, at relatively high densities and sufficiently strong interactions, clusters are formed, even in the presence of a completely repulsive potential. We evaluate the static density response function of this system across the transition from the liquid to the cluster liquid phases. Such quantity reveals the density modulations induced by a weak periodic external potential, and is maximal at the clustering wavevector. It is known that this response function is proportional to the static structure factor in the classical regime at high temperature, while for this zero-temperature quantum systems, we extract it from the dynamical structure factor evaluated with quantum Monte Carlo methods.