Published in the Research School of Physics Event Horizon
Vol43 Issue73 11–15 June 2018

In the recent paper PRL 119, 165701 (2017),  Xiwen Guan from TP in collaboration with the experimental team from University of Science and Technology of China reported their observation of quantum criticality and the Tomonaga-Luttinger liquid (TLL) in one-dimensional (1D) Bose gases, see https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.119.165701.

The observation of TLL features has been a long-standing challenge. Using a high-resolution microscope, they measured the density profiles of quasi-1D trapped ultracold  87Rb atoms by in situ absorption imaging. The density scaling law and the equation of states  were  obtained by rescaling these measurements at different temperatures and chemical potentials.   Based on the obtained equation of states, they  determined two crossover branches that distinguish the quantum critical regime from the classical gas and the TLL through the double-peak structure of the specific heat.  Then, they  probed the propagations of density disturbances and acquired the Luttinger parameters and also found the power-law behavior in the momentum profiles confirms the existence of the TLL. 

This paper was selected as the Editor’s suggestion. Professor Thierry Giamarchi, Department of Quantum Matter Physics, University of Geneva, wrote a Viewpoint on APS webpage Physics: https://physics.aps.org/articles/v10/115. A quotation from professor Giamarchi’s Viewpoint “Without a doubt, this research will open new chapters in the TLL field by inspiring studies that examine how other perturbations (coupling between different 1D chains, spin-orbit coupling, and the like) can lead to novel and potentially exotic states in 1D materials”.