Measurement of the Entropy and Critical Temperature of a Strongly Interacting Fermi Gas

摘要

We report a model-independent measurement of the entropy, energy, andcritical temperature of a degenerate, strongly interacting Fermi gas of atoms.The total energy is determined from the mean square cloud size in the stronglyinteracting regime, where the gas exhibits universal behavior. The entropy ismeasured by sweeping a bias magnetic field to adiabatically tune the gas fromthe strongly interacting regime to a weakly interacting regime, where theentropy is known from the cloud size after the sweep. The dependence of theentropy on the total energy quantitatively tests predictions of thefinite-temperature thermodynamics.