8 research outputs found
Stochastic Master Equations in Thermal Environment
We derive the stochastic master equations which describe the evolution of
open quantum systems in contact with a heat bath and undergoing indirect
measurements. These equations are obtained as a limit of a quantum repeated
measurement model where we consider a small system in contact with an infinite
chain at positive temperature. At zero temperature it is well-known that one
obtains stochastic differential equations of jump-diffusion type. At strictly
positive temperature, we show that only pure diffusion type equations are
relevant
Entanglement in a fermion chain under continuous monitoring
We study the entanglement entropy of the quantum trajectories of a free
fermion chain under continuous monitoring of local occupation numbers. We
propose a simple theory for entanglement entropy evolution from disentangled
and highly excited initial states. It is based on generalized hydrodynamics and
the quasi-particle pair approach to entanglement in integrable systems. We test
several quantitative predictions of the theory against extensive numerics and
find good agreement. In particular, the volume law entanglement is destroyed by
the presence of arbitrarily weak measurement.Comment: 18 pages, 8 figures, 2 new figure
Stochastic Master Equations in Thermal Environment
We derive the stochastic master equations which describe the evolution of open quantum systems in contact with a heat bath and undergoing indirect measurements. These equations are obtained as a limit of a quantum repeated measurement model where we consider a small system in contact with an infinite chain at positive temperature. At zero temperature it is well-known that one obtains stochastic differential equations of jump-diffusion type. At strictly positive temperature, we show that only pure diffusion type equations are relevant