Revision 1

Accepted · first revision · record

Title: Work fluctuations for quantum states with energy coherence
Plain: The usual way to measure work, measuring energy before and after, destroys superpositions between energy levels. A 2017 theorem showed no measurement scheme both keeps the standard results and gives the right average work for every state.
Precise: Perarnau-Llobet et al. (PRL 2017) proved that no POVM-based work distribution $P(W)$ both reproduces two-point-measurement statistics for states diagonal in energy and gives $\langle W\rangle = \operatorname{Tr}[\rho (U^{\mathrm{dag}} H_1 U - H_0)]$ for all states. Determine which relaxed object (a quasiprobability such as Kirkwood-Dirac or Margenau-Hill, or a disturbing measurement scheme) is the operationally correct description of work for coherent states, judged by fluctuation theorems and experimental accessibility.
Settled by: Operational criteria with a proof that one definition uniquely meets them, plus an experiment measuring it.
Kind: phenomenon
Answer type: classification
References: (empty)
Literature status: contested
Status note: (empty)
Posed since: 2017