Berlin 2024 – scientific programme

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QI: Fachverband Quanteninformation

QI 31: Decoherence and Open Quantum Systems

QI 31.7: Talk

Friday, March 22, 2024, 11:15–11:30, HFT-FT 101

Developing efficient open quantum systems methods for time-dependent Hamiltonians — •Steffen Wilksen, Frederik Lohof, and Christopher Gies — Institute for Theoretical Physics, University of Bremen, Bremen, Germany

In various quantum technological applications, the fidelity of quantum gates realized by switching operations is fundamentally limited by both the switching speed and the energy separation of the corresponding states, as stated by the adiabatic theorem. While analytic solutions exist for simplified, isolated systems, like the Landau-Zener problem, various open-quantum-system methods need to be employed to investigate the effects of dissipation and dephasing to enable quantitative predictions. The purpose of this talk is to review established methods from open quantum systems and discuss their applicability and limitations in the context of quantum technology applications. The Landau-Zener problem will be extended to coupling to an external reservoir using a modified Bloch-Redfield approach. We compare this to numerically exact treatments and discuss the role of the Born-Markov approximation in the context of quantum repeater protocol simulations.

Keywords: Open quantum systems; Quantum repeater; Redfield equation; Adiabatic theorem; Landau-Zener