Unmasking Collective Motion in One-Dimensional Bose Gases at Finite Temperature

An international collaboration led by Prof. Giulia De Rosi (Universitat Politècnica de Catalunya, Barcelona), together with Caroline Mauron and Prof. Karen Kheruntsyan (University of Queensland, Brisbane), has uncovered new connections between microscopic and macroscopic properties in quantum many-particle systems across all temperatures.

Their work reveals how these properties evolve across a characteristic “anomaly temperature”, where quantum effects dominant at low temperatures and classical effects prevalent at high temperatures become comparable, regardless of interparticle interaction strength. This advance has broad relevance, spanning from atomic and nuclear matter to solid-state, electronic, and spin systems, including the onset of superfluid, superconducting, and Bose–Einstein condensation phase transitions.

In recent years, the discovery of the hole-induced anomaly—pioneered by Prof. Giulia De Rosi and her colleagues from the BQMC group at UPC—has revealed how thermal excitations govern the temperature dependence of both macroscopic thermodynamic properties and microscopic correlations in one-dimensional Bose systems. Understanding the behavior of these bosonic ensembles is crucial for fundamental research and for the development of future quantum technologies, including high-critical-temperature superconductors and quantum computers. Similar systems have been experimentally realized since 2004 using ultracold atomic gases.

In their study, published as a Letter in the prestigious open-access journal Physical Review Research, Mauron, Kheruntsyan, and De Rosi show that thermal excitations—strongly influenced by the anomaly—also shape how particles move together, leading to two distinct collective oscillation frequencies that persist from zero to high temperatures, in contrast with previous predictions. They further demonstrate that the anomaly temperature marks a boundary between different dynamics of interparticle collisions and explains the absence of the collisional regime at intermediate temperatures predicted in earlier theories.

These findings could be tested in ultracold atom experiments and are expected to stimulate further research aimed at uncovering the microscopic behavior of a wide range of quantum interacting many-particle systems that exhibit similar anomalies.

Reference: 

Mauron, C., Kheruntsyan, K. V., & De Rosi, G. (2026). Particle-hole origin of thermal beating in dipole-compression modes of a one-dimensional Bose gas. Physical Review Research, 8(3), L032003.