Abnormal Superfluid Fraction of Harmonically Trapped Few-Fermion Systems

POSTER

Abstract

Superfluidity is a fascinating phenomenon that, at the macroscopic scale, leads to dissipationless flow and the emergence of vortices. While these macroscopic manifestations of superfluidity are well described by theories that have their origin in Landau's two-fluid model, our microscopic understanding of superfluidity is far from complete. Using analytical and numerical \textit{ab initio} approaches, this work determines the superfluid fraction and local superfluid density of small harmonically trapped two-component Fermi gases as a function of the interaction strength and temperature. At low temperature, we find that the superfluid fraction is, in certain regions of the parameter space, negative. This counterintuitive finding is traced back to the symmetry of the system's ground state wave function, which gives rise to a diverging quantum moment of inertia $I_{\mathrm{q}}$. Analogous abnormal behavior of $I_{\mathrm{q}}$ has been observed in even-odd nuclei at low temperature. Our predictions can be tested in modern cold atom experiments.

Authors

  • Yangqian Yan

    Washington State University

  • William H. Dowd

    Oregon State University, University of Washington, University of Hong Kong, University of Tennessee, Oak Ridge National Laboratory, University of British Columbia, Univ of Washington, Univ of Cambridge, Michigan State University, Universit\'e de Caen, Argonne National Laboratory, Texas A\&M University -Commerce, Texas A\&M University, Department of Physics, University of Idaho, Moscow, Idaho 83844, USA, Universidad de Salamanca, E-37008 Salamanca, Spain, Department of Physics, Florida State University, Tallahassee, Florida 32306, USA, University of Cambridge, Institute of Astronomy, University of Cambridge, Canadian Institute for Theoretical Astrophysics, University of Toronto, Seoul National University, Chungnam National University, Department of Physics, Oregon State University, TRIUMF, Roosevelt High School, Department of Physics, University of Washington, Oregon State Department of Chemistry, Oregon State School of Electrical Engineering and Computer Science, Oregon State Department of Physics, University of Idaho, Lawrence Livermore National Laboratory, Idaho National Laboratory, Pacific Northwest National Laboratory, Carnegie Institution of Washington, Department of Chemistry, Oregon State University, School of Electrical Engineering and Computer Science, Oregon State University, Washington State University, Harvard University, Idaho Accelerator Center, Idaho Accelerator Center, Idaho State University, 1500 Alvin Ricken drive, Pocatello, ID 83201, USA, CENPA, University of Washington, Physics Division, ANL, NSCL, Michigan State University, Division, ANL, LPC, CAEN, France, Paul Scherrer Institute, US Geological Survey, 12201 Sunrise Valley Drive, Reston, VA, 20192, USA, University of Calgary Department of Physics and Astronomy, University of Calgary Department of Geoscience, None, University of the Fraser Valley, Univ of California, Berkeley, Simon Fraser University, Los Alamos Natl. Lab., University of Science and Technology of China, Hefei, U of Washington, Georgia Institute of Technology, Washington State Univ, National Institute of Standards and Technology and University of Maryland, American University