Freiburg 2019 – wissenschaftliches Programm
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FM: Fall Meeting
FM 40: Poster: Quantum Computation: Hardware Platforms
FM 40.9: Poster
Dienstag, 24. September 2019, 16:30–18:30, Tents
Optimal control pulses for a scalable quantum memory — •Nicolas Wittler, Shai Machnes, and Frank K. Wilhelm — Saarland University
Achieving high fidelities for operations on systems with low anharmonicity and complex crowded spectra, such as transmon qubits, is in general required for scalable quantum technologies.
A promising implementation of a quantum memory for a transmon consists of using an electromagnetic mode of the 3D cavity that is already used for readout and control of the transmon, as shown in an experiment by Frank Deppe’s group at the Walther-Meißner-Institute in Munich.
The read and write operations for this memory are exchanges of excitations between the qubit and cavity. In order to profit of the life time of the cavity state (T1 = 9.5 µ s, T2 = 13 µ s) compared to the transmon (T1 = 1.4 µ s, T2 = 3.5 µ s), these gates must be fast and accurate. The high drive power needed to reach short gate times makes it necessary to control leakage out of the computational subspace into higher transmon states.
With theoretical pulse shaping techniques such as DRAG and GOAT that engineer the frequency spectrum of a control pulse, unwanted transitions can be suppressed and an increase in fidelity or shortening of the gate time can be achieved.