Physics Special Theory Seminar with Eric Lutz on Converting quantum statistics into work

Heat engines convert thermal energy into mechanical work both in the classical and quantum regimes. However, quantum theory offers genuine non-classical forms of energy, different from heat, which so far have not been exploited in cyclic engines. I will present an experimental realization a quantum many-body engine fuelled by the energy difference between fermionic and bosonic ensembles of ultracold particles that follows from the Pauli exclusion principle. Employing a harmonically trapped superfluid gas of Li atoms close to a magnetic Feshbach resonance allows one of effectively change the quantum statistics from Bose–Einstein to Fermi–Dirac, by tuning the gas between a Bose–Einstein condensate of bosonic molecules and a unitary Fermi gas (and back) through a magnetic field. The quantum nature of such a Pauli engine is revealed by contrasting it with an engine in the classical thermal regime and with a purely interaction-driven device. These results establish quantum statistics as a useful thermodynamic resource for work production.

This lecture was made possible by the William C. Ferguson fund.