Collective operations can extremely reduce work fluctuations

Martí Perarnau-Llobet*, Raam Uzdin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


We consider work extraction from N copies of a quantum system. When the same work-extraction process is implemented on each copy, the relative size of fluctuations is expected to decay as . Here, we consider protocols where the copies can be processed collectively, and show that in this case work fluctuations can disappear exponentially fast in N. As a consequence, a considerable proportion of the average extractable work can be obtained almost deterministically by globally processing a few copies of the state. This is derived in the two canonical scenarios for work extraction: (i) in thermally isolated systems, where corresponds to the energy difference between initial and passive states, known as the ergotropy, and (ii) in the presence of a thermal bath, where is given by the free energy difference between initial and thermal states.

Original languageAmerican English
Article number083023
JournalNew Journal of Physics
Issue number8
StatePublished - 12 Aug 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2019 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft.


  • Collective processes
  • Quantum thermodynamics
  • Work fluctuations


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