# gst: stochastic Scovil-Schulz-DuBois (SSDB) machine and its three types of cycles

<< Three types of cycles are identified in the quantum jump trajectories of the Scovil–Schulz-DuBois (SSDB) machine. An R cycle as refrigeration, an H cycle as a heat engine, and an N cycle in which the machine is neutral. >>

AA << find that in the large time limit, whether the machine operates as a heat engine or refrigerator depends on the ratio between the numbers of R cycles and H cycles per unit time. Further increasing the hot bath temperature above a certain threshold does not increase the machine's power output. The cause is that, in this situation, the N cycle has a greater probability than the H cycle and R cycle. >>

<< Although the SSDB machine operates by randomly switching between these three cycles, at the level of a single quantum jump trajectory, its heat engine efficiency and the refrigerator's coefficient of performance remain constant. >>

Fei Liu, Jiayin Gu. Stochastic Scovil–Schulz-DuBois machine and its three types of cycles. Phys. Rev. E 111, 014108. Jan 3, 2025. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.014108 

arXiv: 2409.04124v2 [cond-mat.stat-mech]. Jan 5, 2025. 

https://arxiv.org/abs/2409.04124

Keywords: gst, stochasticity, quantum heat engines & refrigerators, stochastic Scovil–Schulz-DuBois (SSDB) machine