Hannover 2016 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 8: Quantum Information: Concepts and Methods II

Q 8.2: Talk

Monday, February 29, 2016, 14:45–15:00, e214

Practical applications of compressed sensing in quantum state tomography — •Carlos Riofrio, Adrian Steffens, and Jens Eisert — Dahlem center for complex quantum systems, Freie Universität Berlin, 14195 Berlin, Germany.

As quantum systems get closer to technological applications, the problem of identifying, certifying, and characterizing them becomes more daunting. In fact, a complete characterization of a quantum system requires determining a number of parameters that grow exponentially with the system size. New paradigms that allow for efficient signal processing must be developed and tested to overcome this roadblock. In this talk, we present an overview of the most recent developments in quantum state tomography via compressed sensing. We show a complete analysis based on experimental data from two different systems: First, a photonic circuit that prepares highly entangled photons corresponding to 4-qubit states, which we use as a testbed to showcase our tomographic procedure in a variety of scenarios; Second, a 7-qubit system of trapped ions which encodes a single logical qubit via a color code, in which highly incomplete data is observed. We show how compressed sensing and model selection ideas can be combined, which is necessary in practice when little information is available.