Weak measurement and rapid state reduction in entangled bipartite quantum systems

Charles Hill, Jason Ralph
2007 New Journal of Physics  
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
more » ... en projective and continuous measurements with regard to state-purification.
doi:10.1088/1367-2630/9/5/151 fatcat:yjti524odvgpvlylggiizdu7du