Colloquium - "Exploring the Thermodynamics and Hydrodynamics of a Universal Fermi Gas"

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Venue:CP 220

Abstract: One of the greatest challenges in modern physics is to understand the behavior of an ensemble of strongly interacting particles. Many strongly interacting many-body systems (such as high temperature superconductor, neutron star and Fermi gases) share the same universal thermodynamic and hydrodynamic properties at unitary. Therefore, an ultracold Fermi gas can be used as a “quantum simulator” to study many fundamental physics from astrophysical to nuclear physics. Thermodynamics quantities (energy and entropy) and transport property (shear viscosity) have been measured with such strongly interacting Fermi gases in our lab. Shear viscosity is extracted from studying the decay rate of collective mode at low temperature and direct expansion of gas at high temperature. It shows universal temperature scale. The results are compared to conjecture of string theory, suggesting that the trapped Fermi gases are the best fluid ever observed. Optical control Feshbach resonance with molecular dark state is also discussed in this talk. The loss can be greatly depressed due to quantum interference. It will open many new study directions in strongly interacting quantum gases. I will conclude by discussing ways to combine these techniques to address outstanding questions in many-body dynamics, relativistic physics and beyond.