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

Abstract

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 HamiltonianĤ 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.

Quantum collision models: Open system dynamics from repeated interactions

“…( 64) and (65)]. This was used for proposing a definition of work independent of the S free Hamiltonian [140] 8. Non-Markovian collision models So far we have been focusing on memoryless (i.e.…”

Quantum and Classical Ergotropy from Relative Entropies

“…Exploiting this approach [ 20 , 21 , 22 ], we define the geometric relative entropy . With this, it becomes particularly transparent to characterize the one-time measurement approach to quantum work [ 23 , 24 , 25 , 26 , 27 ]. In this paradigm, work is determined by first measuring the energy of the system, and then letting it evolve under time-dependent dynamics.…”

Inferring work by quantum superposing forward and time-reversal evolutions

“…In the TPM scheme, work is represented as the difference between the initial and final energies of the system, obtained by performing two projective measurements of the Hamiltonian at the beginning and at the end of the forward as well as of the time-reversal process. Extensions to non-ideal measurements [29][30][31] and variants of the TPM scheme [32][33][34][35][36][37] have been also considered recently. The TPM approach has been directly implemented in several experiments [38][39][40][41].…”