Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 19: Materials and Devices for Quantum Technology 1

HL 19.3: Vortrag

Mittwoch, 7. September 2022, 10:15–10:30, H34

Time Dependent Redfield Dynamics of Semiconductor Quantum-Dot Molecules — •Steffen Wilksen, Isabell Hüllen, Frederik Lohof, and Christopher Gies — Institute for Theoretical Physics, University of Bremen, Bremen, Germany

Semiconductor quantum dots provide a promising platform for applications in quantum information technologies, like quantum repeaters, which enable secure quantum communication over long distances. Two quantum dots, seperated by a small tunneling layer, can be combined into so-called quantum dot molecules (QDMs) which exhibit properties similar to classical molecules. These properties can be tuned by applying an external electric field, which allows to perform switching operations on QDM-based qubits.

The QDM can not be treated in isolation, since the electron-phonon interaction plays a crucial role in the systems dynamics. We thus treat the QDM as an open quantum system coupled to the external phonon reservoir. The application of a time-dependent electric field not only changes the QDM's properties, but also the form of the electron-phonon interaction, which allows for a time dependent tuning of dissipative effects.

We investigate the behaviour of the system for different switching speeds of the electric field using a time-dependent Redfield master equation approach. Slow switching leads to predictable and controlled adiabatic behaviour but limits the clock rate of the quantum repeater, whereas fast switching allows for higher clock rates but leads to non-adiabatic behaviour.