Finite-temperature ferromagnetic transition in coherently coupled Bose gases

Year: 2023

Authors: Roy A., Ota M., Dalfovo F., Recati A.

Autors Affiliation: Univ Trento, Pitaevskii BEC Ctr, CNR, INO, Via Sommar 14, I-38123 Trento, Italy; Univ Trento, Dipartimento Fis, Via Sommar 14, I-38123 Trento, Italy; Indian Inst Technol Mandi, Sch Phys Sci, Mandi 175075, HP, India; INFN, Trento Inst Fundamental Phys & Applicat, I-38123 Povo, Italy.

Abstract: A paramagnetic-ferromagnetic quantum phase transition is known to occur at zero temperature in a twodimensional coherently coupled Bose mixture of dilute ultracold atomic gases provided the interspecies interaction strength is large enough. Here we study the fate of such a transition at finite temperature by performing numerical simulations with the stochastic (projected) Gross-Pitaevskii formalism, which includes both thermal and beyond mean-field effects. By extracting the average magnetization, the magnetic fluctuations and characteristic relaxation frequency (or critical slowing down), we identify a finite-temperature critical line for the transition. We find that the critical point shifts linearly with temperature and, in addition, the three quantities used to probe the transition exhibit a temperature power-law scaling. The scaling of the critical slowing down is found to be consistent with thermal critical exponents and is very well approximated by the square of the spin excitation gap at zero temperature.

Journal/Review: PHYSICAL REVIEW A

Volume: 107 (4)      Pages from: 43301-1  to: 43301-10

More Information: This work is supported by Provincia Autonoma di Trento and from INFN-TIFPA under the project FISh. We acknowledge the CINECA award under the ISCRA initiative, for the availability of high-performance computing resources and support. A. Roy acknowledges the support of the Science and Engineering Research Board (SERB), Department of Science and Technology, Government of India under Project No. SRG/2022/000057 and IIT Mandi seed-grant funds under Project No. IITM/SG/AR/87. A. Roy acknowledges National Supercomputing Mission (NSM) for providing computing resources of PARAM Himalaya at IIT Mandi, whi ch is implemented by C-DAC and supported by the Ministry of Electronics and Information Technology (MeitY) and Department of Science and Technology (DST), Government of India
KeyWords: Gross-pitaevskii Equation; Dynamics; Mixtures; Condensation; Separation
DOI: 10.1103/PhysRevA.107.043301

Citations: 1
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