Mainz 2017 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 23: Quantum Information: Concepts and Methods IV
Q 23.8: Vortrag
Dienstag, 7. März 2017, 16:15–16:30, P 2
Guaranteed recovery of quantum processes from few measurements — •Martin Kliesch1,2, Richard Kueng2, Jens Eisert3, and David Gross2 — 1University of Gdansk, Poland — 2University of Cologne, Germany — 3Freie Universität Berlin, Germany
Quantum process tomography is the task of reconstructing unknown quantum channels from measured data. In this work, we introduce compressed sensing-based methods that facilitate the reconstruction of quantum channels of low Kraus rank. The measurements are obtained from sending pure states into the channel and measuring expectation values of observables without the use of ancilla systems. We prove recovery guarantees for three different reconstruction algorithms that using an essentially optimal number of measurements. The reconstructions are based on a trace, diamond, and ℓ2-norm minimization, respectively. Our recovery guarantees are uniform in the sense that with one random choice of measurement settings all quantum channels can be recovered equally well. Moreover, stability against arbitrary measurement noise and robustness against violations of the low-rank assumption is guaranteed. Numerical studies demonstrate the feasibility of the approach.