2020/07/31 by Lucas Madeira, Arnol Daniel García-Orozco, Arnol D. García-Orozco +4
Engineering · Physics and Astronomy · #Amplitude #Cold Atom Physics and Bose-Einstein Condensates #Entropy (arrow of time) #Excitation #Fluid dynamics and aerodynamics studies #Generalized relative entropy #H-theorem #Quantum #Quantum turbulence #Quantum, superfluid, helium dynamics #Superfluid helium-4 #Turbulence #cond-mat.quant-gas
paper · pdf · doi:10.3390/e22090956
published as Entropy 22(9), 956 (2020) · 14 pages, 5 figures
arxiv created 2020/08/30 · openalex publication_date 2020/08/30 · arxiv updated 2020/09/01 · openalex created_date 2020/09/08 · openalex updated_date 2026/08/06
Quantum turbulence deals with the phenomenon of turbulence in quantum fluids, such as superfluid helium and trapped Bose-Einstein condensates (BECs). Although much progress has been made in understanding quantum turbulence, several fundamental questions remain to be answered. In this work, we investigated the entropy of a trapped BEC in several regimes, including equilibrium, small excitations, the onset of turbulence, and a turbulent state. We considered the time evolution when the system is perturbed and let to evolve after the external excitation is turned off. We derived an expression for the entropy consistent with the accessible experimental data, which is, using the assumption that the momentum distribution is well-known. We related the excitation amplitude to different stages of the perturbed system, and we found distinct features of the entropy in each of them. In particular, we observed a sudden increase in the entropy following the establishment of a particle cascade. We argue that entropy and related quantities can be used to investigate and characterize quantum turbulence.