Weak measurement and rapid state reduction in bipartite quantum systems

Abstract

In this paper we consider feedback control algorithms for the rapid purification of a bipartite state consisting of two qubits, when the observer has access to only one of the qubits. We show 1) that the algorithm that maximizes the average purification rate is not the same as that that for a single qubit, and 2) that it is always possible to construct an algorithm that generates a deterministic rate of purification for {\em both} qubits. We also reveal a key difference between projective and continuous measurements with regard to state-purification.

4 pages, 3 figures

References in corpus (5)

• Deterministic Dicke state preparation with continuous measurement and control
• Qubit feedback and control with kicked quantum nondemolition measurements: A quantum Bayesian analysis
• Reconsidering Rapid Qubit Purification by Feedback
• Quantum trajectories for the realistic measurement of a solid-state charge qubit
• Weak measurement and rapid state reduction in bipartite quantum systems

Cited by in corpus (5)

• Rapid Measurement of Quantum Systems using Feedback Control
• Weak measurement and control of entanglement generation
• Quantum Feedback Control: How to use Verification Theorems and Viscosity Solutions to Find Optimal Protocols
• Weak measurement and rapid state reduction in bipartite quantum systems
• Rapid-purification protocols for optical homodyning