Colloquium Schedule

Colloquium: Thursday, October 18th, 4:10 PM, Lewis Lab 316

Scale Invariant Strongly Interacting Fermi Gases

John E. Thomas

Optically-trapped, ultra-cold gases of spin ½-up and spin ½- down 6Li atoms model high temperature superconductors, neutron matter, and even the hydrodynamics of a quarkgluon plasma, a state of matter at 2 trillion degrees that existed microseconds after the Big Bang. A bias magnetic field tunes the gas to a collisional (Feshbach) resonance, where the dilute atomic cloud becomes a scale-invariant, stronglyinteracting fluid: Shock waves are produced when two clouds collide. Remarkably, the ratio of the shear viscosity to the entropy density of such clouds is comparable to that of a quark-gluon plasma, close to the minimum ratio conjectured for a “perfect fluid” using scale-invariant conformal field theory methods. I will describe our recent observations of scale-invariant expansion, our latest results on quantum shear viscosity, and preliminary data on hydrodynamic flow from an optical box potential into a channel.

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Physics and Astronomy Colloquia are usually scheduled for Thursdays at 4:10 PM in Lewis Lab room 316. Refreshments and snacks are available in the nearby coffee room at 3:45 PM.

Physics Colloquium Schedule for FALL 2018

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