Estimation of the Repeatedly-Projected Reduced Density Matrix under Decoherence
arXiv:0711.2751 · doi:10.1103/PhysRevA.77.042114
Abstract
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.
14 pages
References in corpus (13)
- Quantum Zeno effect by general measurements
- Control of decoherence: analysis and comparison of three different strategies
- Temporal behavior of quantum mechanical systems
- Purification through Zeno-like Measurements
- Preparation and Entanglement Purification of Qubits through Zeno-like Measurements
- Solution of the Lindblad Equation in the Kraus Representation
- Long-range entanglement generation via frequent measurements
- Distillation of Entanglement between Distant Systems by Repeated Measurements on Entanglement Mediator
- Distilling angular momentum nonclassical states in trapped ions
- Qubit state guidance without feedback
- A Simple Scheme to Entangle Distant Qubits from a Mixed State via an Entanglement Mediator
- Influence of dissipation on the extraction of quantum states via repeated measurements
- Steering Distillation by "Pulsed" and "Continuous" Measurements