Universal Thermodynamics of a Strongly-Interacting Fermi Gas
John E. Thomas, Joseph Kinast, and Andrey Turlapov
Department of Physics, Duke University, Durham, NC, 27708-0305, USA
Strongly-interacting Fermi gases provide a paradigm for exotic systems in nature, ranging from high
temperature superconductors to neutron stars. Using precision energy input methods and empirical
thermometry, we measure the properties of a 50-50 mixture of spin-up and spin-down fermionic 6 Li
atoms, confined in an optical trap. The gas is magnetically tuned near the center of a broad Feshbach
scattering resonance, where the scattering length far exceeds the interparticle spacing, producing scaleinvariant, universal strong interactions. The cloud exhibits nearly perfect hydrodynamics, providing
links to recent string theory predictions and to observations of elliptic flow in a quark-gluon plasma. Our
measurements of both the heat capacity and the damping rate reveal transitions in behavior at 30% of
the Fermi temperature, indicating the onset of high temperature superfluidity.
Sorting category: Aa Quantum gases, fluids and solids
Keywords: Fermi gases, superfluidity, heat capacity, damping
INVITED PAPER
LT1672