Superfluidity and Chaos


  Geva Arwas  ,  Amichay Vardi  ,  Doron Cohen  
Ben-Gurion University

The hallmark of superfluidity is the appearance of a quantized metastable circulating current. The Landau criterion links the metastability of a vortex state to its spectral stability, i.e. to the inaccessibility of elementary excitations connecting it to other states with the same energy. In low dimensional systems, superfluid vortex states can exist due to their dynamical stability even if they are spectrally unstable. This traditional paradigm associate superfluid vortex states with stationary stable fixed points in phase space. Hence, Bogoliubov de Gennes (BdG) stability analysis is normally used to determine the feasibility of such states. In this work we challenge this traditional criterion and highlight the role of chaos in the analysis, thus explaining the existence of current carrying eigenstates which are neither spectrally-stable nor dynamically-stable.