6533b7d1fe1ef96bd125c32f
RESEARCH PRODUCT
Estimation of the Repeatedly-Projected Reduced Density Matrix under Decoherence
Antonino MessinaKazuya YuasaHiromichi NakazatoBenedetto Militellosubject
PhysicsDensity matrixQuantum PhysicsQuantum decoherenceSettore FIS/02 - Fisica Teorica Modelli E Metodi MatematiciAnalytical expressionsDephasingsteFoundations of quantum mechanicFOS: Physical sciencesState (functional analysis)DecoherenceAtomic and Molecular Physics and OpticsSettore FIS/03 - Fisica Della MateriaClassical mechanicsDissipative systemReduced density matrixopen systemQuantum Physics (quant-ph)Finite setdescription
Decoherence is believed to deteriorate the ability of a purification scheme that is based on the idea of driving a system to a pure state by repeatedly measuring another system in interaction with the former and hinder for a pure state to be extracted asymptotically. Nevertheless, we find a way out of this difficulty by deriving an analytic expression of the reduced density matrix for a two-qubit system immersed in a bath. It is shown that we can still extract a pure state if the environment brings about only dephasing effects. In addition, for a dissipative environment, there is a possibility of obtaining a dominant pure state when we perform a finite number of measurements.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2007-11-17 |