2016/01/18 by Debmalya Das, Arvind
Computer Science · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Gaussian #Measure (data warehouse) #Momentum (technical analysis) #Position (finance) #Projective test #Quantum #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum state #State (computer science) #Weak measurement #quant-ph
paper · pdf · doi:10.1088/1751-8121/aa608f
8 pages, Revtex, minor changes
arxiv created 2016/01/18 · openalex created_date 2016/06/24 · openalex publication_date 2017/02/15 · arxiv updated 2017/04/05 · openalex updated_date 2026/08/05
Abstract We present a scheme to estimate Gaussian states of one-dimensional continuous variable systems, based on weak (unsharp) quantum measurements. The estimation of a Gaussian state requires us to find position ( q ), momentum ( p ) and their second order moments. We measure q weakly and follow it up with a projective measurement of p on half of the ensemble, and on the other half we measure p weakly followed by a projective measurement of q . In each case we use the state twice before discarding it. We compare our results with projective measurements and demonstrate that under certain conditions such weak measurement-based estimation schemes, where recycling of the states is possible, can outperform projective measurement-based state estimation schemes. We establish beyond statistical fluctuations that our method works better for small ensemble sizes.