Rostock 2019 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 20: Quantum Information (Solid State Systems)
Q 20.5: Talk
Monday, March 11, 2019, 17:30–17:45, S HS 002 Chemie
Effective T2 enhancement by feed forward decoupling — •Georg Braunbeck, Andreas Michael Waeber, Maximilian Kaindl, and Friedemann Reinhard — Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
Tuning a quantum sensor into maximum sensitivity generally also renders it most vulnerable to noise. The state-of-the-art solution is to tailor the sensor’s spectral sensitivity, usually implemented via complex dynamical decoupling sequences.
In my talk, I will present an alternative approach that we termed "feed forward decoupling". It is based on the insight that we can remove the decoherence effect of a classical noise source by recording it alongside the quantum signal and adapting the readout phase to the result. I will present a proof-of-concept implementation on a nitrogen-vacancy center disturbed by a randomly fluctuating current in a nearby conductor. The scheme effectively increases T2 in a Hahn echo measurement and can moreover be extended to a self-learning algorithm that learns the noise-correction on the fly.
Finally, I will discuss the limits and possible applications of this method. One of the most promising areas are experiments using strong control pulses, where small fluctuations translate into strong decoherence.