Fig. 1
From: An interaction-driven many-particle quantum heat engine and its universal behavior
Interaction-driven quantum cycle. The working substance is driven through four sequential isochoric strokes alternating heating and cooling processes at different temperature \(T\) with isentropes in which the interparticle interaction strength \(c\) is ramped up and down. The color coding indicates the mean energy across the \(T-c\) plane. The dashed lines correspond to the thermal entropy calculated from the thermodynamic Bethe ansatz equation of the Lieb-Liniger gas.21,22,23,24 The effective temperature assigned along the isentropes results from scale invariance in the energy spectrum, that holds for strong coupling and the Luttinger liquid region; see Section “Universal efficiency at low temperature” and the Supplementary Information Section I
