Work as an external quantum observable and an operational quantum work fluctuation theorem

Research output: Contribution to journalResearch articleContributedpeer-review


We propose a definition of externally measurable quantum work in driven systems. Work is given as a quantum observable on a control device which is forcing the system and can be determined without knowledge of the system Hamiltonian $H_S$ . We argue that quantum work fluctuation theorems which rely on the knowledge of $H_S$ are of little practical relevance, contrary to their classical counterparts. Using our framework, we derive a fluctuation theorem which is operationally accessible and could in principle be implemented in experiments to determine bounds on free energy differences of unknown systems.


Original languageEnglish
Number of pages9
JournalPhysical Review Research
Publication statusPublished - 2020

External IDs

Scopus 85098423574
ORCID /0000-0002-7806-3525/work/142234182
ORCID /0000-0002-1864-4520/work/142234861



  • quantum work in driven systems