Erlangen 2022 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 67: Rydberg Systems (joint session Q/A)

Q 67.4: Talk

Friday, March 18, 2022, 11:15–11:30, Q-H14

Controlled Dephasing and Unequal Time Correlations in Rydberg Qubits — •Andre Salzinger¹, Kevin T. Geier^2,3, Titus Franz¹, Sebastian Geier¹, Nithiwadee Thaicharoen⁴, Annika Tebben¹, Clément Hainaut⁵, Robert Ott³, Martin Gärttner¹, Gerhard Zürn¹, Philipp Hauke², and Matthias Weidemüller¹ — ¹Physikalisches Institut Heidelberg — ²University of Trento — ³Institut für Theoretische Physik Heidelberg — ⁴Chiang Mai University — ⁵Université Lille

Engineering open system dynamics relies on restricted degrees of freedom of a larger system. Equivalently, master equations can be derived by averaging over realisations of stochastic processes. We present experimental results for qubit rotations subjected to random phase walks, which are sampled from 1D Brownian motion. The observed realisation average follows a Lindblad description with decay parameter γ given by the variance of sampled phase walks. We use this controlled dephasing in a linear-response scheme to extract the unequal-time anticommutator in an ensemble of driven two-level systems by coupling to an ancilla level. This acts as a first benchmark for future measurements in many-body systems far from equilibrium, where unequal-time commutator and anticommutor probe fluctuation-dissipation relations.