Work and quantum phase transitions: quantum latency.
Physical review. E, Statistical, nonlinear, and soft matter physics 89:6 (2014) 062103
Abstract:
We study the physics of quantum phase transitions from the perspective of nonequilibrium thermodynamics. For first-order quantum phase transitions, we find that the average work done per quench in crossing the critical point is discontinuous. This leads us to introduce the quantum latent work in analogy with the classical latent heat of first order classical phase transitions. For second order quantum phase transitions the irreversible work is closely related to the fidelity susceptibility for weak sudden quenches of the system Hamiltonian. We demonstrate our ideas with numerical simulations of first, second, and infinite order phase transitions in various spin chain models.Work and quantum phase transitions: Quantum latency
Physical Review E American Physical Society (APS) 89:6 (2014) 062103
Transitionless quantum driving in open quantum systems
New Journal of Physics IOP Publishing 16:5 (2014) 053017
Universal optimal quantum correlator
International Journal of Quantum Information 12:7-8 (2014)
Abstract:
Recently, a novel operational strategy to access quantum correlation functions of the form Tr[AρB] was provided in [F. Buscemi, M. Dall'Arno, M. Ozawa and V. Vedral, arXiv:1312.4240]. Here we propose a realization scheme, that we call partial expectation values, implementing such strategy in terms of a unitary interaction with an ancillary system followed by the measurement of an observable on the ancilla. Our scheme is universal, being independent of ρ, A, and B, and it is optimal in a statistical sense. Our scheme is suitable for implementation with present quantum optical technology, and provides a new way to test uncertainty relations.Quantum entanglement
Nature Physics Springer Nature 10:4 (2014) 256-258