I will present an investigation into thermodynamic cycles in ultra cold atoms when the interactions between the atoms plays in important role. The first example uses a Bose–Einstein condensate with nonlinear interactions as the working medium and exploits a Feshbach resonance to change the interaction strength of the BEC. This allows to produce work by expanding and compressing the gas, and the power-output can be optimised using a shortcut-to-adiabticity.
The second example investigates the operation of a quantum Otto cycle near a quantum critical point. Specifically we look at the pinning transition of a Tonks-Girardeau gas, when particles will become pinned at the minima of an optical lattice if they are commensurate with the number of lattice sites. Due to the energy gap opened at the pinning transition this provides a performance boost to the many-body system over a comparable ensemble of single particle engines.