2005/08/31 by Joshua Combes, Kurt Jacobs
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1103/physrevlett.96.010504
published as Phys. Rev. Lett. 96, 010504 (2006) · 4 pages, revtex4, 1 eps figure. v2: improved presentation; v3: published version, some typos corrected
arxiv created 2006/01/24 · arxiv updated 2009/12/01
We consider using Hamiltonian feedback control to increase the speed at which a continuous measurement purifies (reduces) the state of a quantum system, and thus to increase the speed of the preparation of pure states. For a measurement of an observable with N equispaced eigenvalues, we show that there exists a feedback algorithm which will speed up the rate of state-reduction by at least a factor of 2(N+1)/3.