Measurement of the order parameter and its spatial fluctuations across Bose-Einstein condensation
Authors: Wolswijk L., Mordini C., Farolfi A., Trypogeorgos D., Dalfovo F., Zenesini A., Ferrari G., Lamporesi G.
Autors Affiliation: Univ Trento, INO CNR BEC Ctr, I-38123 Povo, Italy; Univ Trento, Dipartimento Fis, I-38123 Povo, Italy; Swiss Fed Inst Technol, Inst Quantum Elect, Otto Stern Weg 1, CH-8093 Zurich, Switzerland; Swiss Fed Inst Technol, Quantum Ctr, CH-8093 Zurich, Switzerland; Inst Nanotechnol, CNR Nanotec, Via Monteroni, I-73100 Lecce, Italy
Abstract: We investigate the strong out-of-equilibrium dynamics occurring when a harmonically trapped ultracold bosonic gas is evaporatively cooled across the Bose-Einstein condensation transition. By imaging the cloud after free expansion, we study how the cooling rate affects the timescales for the growth of the condensate order parameter and the relaxation dynamics of its spatial fluctuations. We find evidence of a delay on the condensate formation related to the collisional properties and a universal condensate growth following the cooling rate. Finally, we measure an exponential relaxation of the spatial fluctuations of the order parameter that also shows a universal scaling. Notably, the scaling for the condensate growth and for the relaxation of its fluctuations follow different power laws.
Journal/Review: PHYSICAL REVIEW A
Volume: 105 Pages from: 033316-1 to: 033316-10
More Information: We thank D. Clement and S. Giorgini for stimulating discussions. We acknowledge funding from the European Union´s Horizon 2020 Programme through the NAQUAS project of QuantERA ERA-NET Cofund in Quantum Technologies (Grant Agreement No. 731473) and from Provincia Autonoma di Trento. This work was supported byQ@TN, the joint laboratory between University of Trento, FBK-Fondazione Bruno Kessler, INFN-National Institute for Nuclear Physics and CNR-National Research Council.KeyWords: Phase transitions, Critical phenomena, Bose-Einstein condensationDOI: 10.1103/PhysRevA.105.033316