Rostock 2019 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 3: Quantum Information (Quantum Computing) I

Q 3.2: Talk

Monday, March 11, 2019, 11:00–11:15, S HS 001 Chemie

Certifying quantum memories with coherence — •Timo Simnacher, Nikolai Wyderka, Cornelia Spee, Xiao-Dong Yu, and Otfried Gühne — Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Walter-Flex-Straße 3, 57068 Siegen, Germany

In order to work, quantum computers need reliable and well-characterized routines and devices. The loss of quantum coherence, however, is one of the major obstacles on the way to a scalable platform for quantum computing and the suppression of decoherence is known as one of the DiVincenzo criteria for quantum computers. One main ingredient in any computing architecture is the memory. Quantum computers are no exception and furthermore, quantum memories play a central role in the development of quantum repeaters. Consequently, the search for reliable systems that store quantum states for a reasonable amount of time while preserving quantum properties is an active area of research.

We present a general method to characterize and test these devices based on their ability to preserve coherence. We introduce a quality measure for quantum memories and characterize it in detail for the qubit case. The measure can be estimated from sparse experimental data and may be generalized to characterize other building blocks, such as quantum gates or teleportation schemes.