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Updated: Jun 8, 2026

Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
Suppressing Fermi acceleration in two-dimensional driven billiards
Edson D Leonel1, Leonid A Bunimovich
1Departamento de Estatística, Matemática Aplicada e Computação-IGCE-UNESP-Univ Estadual Paulista, Rio Claro, SP, Brazil.
Abstract:
We consider a dissipative oval-like shaped billiard with a periodically moving boundary. The dissipation considered is proportional to a power of the velocity V of the particle. The three specific types of power laws used are: (i) F∝-V ; (ii) F∝-V(2) and (iii) F∝-V(δ) with 1<δ<2 . In the course of the dynamics of the particle, if a large initial velocity is considered, case (i) shows that the decay of the particle's velocity is a linear function of the number of collisions with the boundary. For case (ii), an exponential decay is observed, and for 1<δ<2 , an powerlike decay is observed. Scaling laws were used to characterize a phase transition from limited to unlimited energy gain for cases (ii) and (iii). The critical exponents obtained for the phase transition in the case (ii) are the same as those obtained for the dissipative bouncer model. Therefore near this phase transition, these two rather different models belong to the same class of universality. For all types of dissipation, the results obtained allow us to conclude that suppression of the unlimited energy growth is indeed observed.
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