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QI: Fachverband Quanteninformation

QI 41: Quantum Computing and Simulation II (joint session Q/QI)

QI 41.7: Vortrag

Freitag, 14. März 2025, 12:45–13:00, AP-HS

Cooling a quantum annealer with a quantum field — •Raphael Menu and Giovanna Morigi — Universität des Saarlandes, Saarbrücken

We analyse the Landau-Zener dynamics of a qubit, which is simultaneously coupled to a dissipative auxiliary system. By tuning the coupling, the qubit dynamics ranges from a dephasing master equation to a strongly coupled qubit-auxiliary system, which is effectively a non-Markovian reservoir for the qubit. We determine the quantum trajectories in the different regimes and analyse the distribution of each trajectory in terms of the time-dependent probability of a diabatic transition. Depending on the strength of the coupling, we observe multipeaked configurations, which undergo transitions to narrow distributions. These transitions are signaled by a higher probability that a jump occurs. The behavior of the probability of a quantum jump as a function of the coupling and of the time of the sweep, in turn, allows us to shed light on the stages of the dynamics when the environment is detrimental and when instead it corrects diabatic transition. It shows, in particular, that memory effects can be beneficial in cooling a quantum system.