Hannover 2010 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 44: Quantum Information: Concepts and Methods III
Q 44.2: Talk
Thursday, March 11, 2010, 10:45–11:00, E 214
State reconstruction from few measurements — •Marcus Cramer1 and Martin Plenio2 — 1Institute for Mathematical Sciences, Imperial College London, UK — 2Institut für Theoretische Physik, Universität Ulm, Germany
Reconstructing a density matrix from measurement data is highly involved both from the experimental and the post-processing point of view: The number of measurements and computational resources needed to process them are exponentially large in the system size. If one knows that the system is in thermal equilibrium, one can do much better: We introduce a scheme that relies only on a linear number of correlation measurements. The computational resources needed to reconstruct the state with high fidelity from these measurements is only polynomial in the system size. The algorithm combines singular value thresholding and matrix product state methods.