Towards an isothermal cold-atom Feshbach engine

Tuning the interaction strength in a Bose gas can produce work [1]. Thus, ultracold atom experiments offer the possibility of designing thermodynamic engines with a quantum-degenerate working fluid whose physical properties can be manipulated with great precision. We present preliminary experimental results on an isothermal engine employing a degenerate Bose gas of lithium. An ultracold cloud confined in a harmonic optical trap is subjected to a sequence of variations of the interaction strength (via a Feshbach resonance), and trapping volume (via compression/decompression of an optical dipole potential). We discuss the results of initial studies of engine performance varying the interaction strength, the adiabaticity of the strokes and the condensed and thermal fractions.

[1] T. Keller et al., Phys. Rev. Res. 2, 033335 (2020)