Equivalence of quantum heat machines, and quantum-thermodynamic signatures

Raam Uzdin, Amikam Levy, Ronnie Kosloff

Research output: Contribution to journalArticlepeer-review

371 Scopus citations


Quantum heat engines (QHE) are thermal machines where the working substance is a quantum object. In the extreme case, the working medium can be a single particle or a few-level quantum system. The study of QHE has shown a remarkable similarity with macroscopic thermodynamical results, thus raising the issue of what is quantum in quantum thermodynamics. Our main result is the thermodynamical equivalence of all engine types in the quantum regime of small action with respect to Planck's constant. They have the same power, the same heat, and the same efficiency, and they even have the same relaxation rates and relaxation modes. Furthermore, it is shown that QHE have quantum-thermodynamic signature; i.e., thermodynamic measurements can confirm the presence of quantum effects in the device. We identify generic coherent and stochastic work extraction mechanisms and show that coherence enables power outputs that greatly exceed the power of stochastic (dephased) engines.

Original languageEnglish
Article number031044
JournalPhysical Review X
Issue number3
StatePublished - 2015
Externally publishedYes


  • Quantum physics


Dive into the research topics of 'Equivalence of quantum heat machines, and quantum-thermodynamic signatures'. Together they form a unique fingerprint.

Cite this