Deffner, SebastianPaz, Juan PabloZurek, Wojciech H.2020-08-122020-08-122016-07-07Sebastian Deffner, Juan Pablo Paz, and Wojciech H. Zurek, Quantum work and the thermodynamic cost of quantum measurements, Phys. Rev. E 94(01) (2016), DOI:https://doi.org/10.1103/PhysRevE.94.010103https://doi.org/10.1103/PhysRevE.94.010103http://hdl.handle.net/11603/19402Quantum work is usually determined from two projective measurements of the energy at the beginning and at the end of a thermodynamic process. However, this paradigm cannot be considered thermodynamically consistent as it does not account for the thermodynamic cost of these measurements. To remedy this conceptual inconsistency we introduce a paradigm that relies only on the expected change of the average energy given the initial energy eigenbasis. In particular, we completely omit quantum measurements in the definition of quantum work, and hence quantum work is identified as a thermodynamic quantity of only the system. As main results we derive a modified quantum Jarzynski equality and a sharpened maximum work theorem in terms of the information free energy. A comparison of our results with the standard approach allows one to quantify the informational cost of projective measurements.5 pagesen-USThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.Public Domain Mark 1.0This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. LawText