Regensburg 2022 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 36: Quantum Coherence and Quantum Information Systems (joint session TT/DY)

DY 36.3: Vortrag

Donnerstag, 8. September 2022, 10:00–10:15, H22

Quantum dynamics of disordered arrays of interacting superconducting qubits: Signatures of quantum collective states — Mikhail Fistul, •Oliver Neyenhuys, Antonia Bocaz, and Ilya Eremin — Theoretische Physik III, Ruhr-Universität Bochum, Bochum 44801, Germany

We study theoretically the collective quantum dynamics occurring in various interacting superconducting qubits arrays (SQAs) in the presence of a spread of individual qubit frequencies. The interaction is provided by mutual inductive coupling between adjacent qubits (short-range Ising interaction) or inductive coupling to a low-dissipative resonator (long-range exchange interaction). In the absence of interaction the Fourier transform of the temporal correlation function of the total polarization (z-projection of the total spin), i.e. the dynamic susceptibility C(ω), demonstrates a set of sharp small magnitude resonances corresponding to the transitions of individual superconducting qubits. We show that even a weak interaction between qubits can overcome the disorder with a simultaneous formation of the collective excited states. This collective behavior manifests itself by a single large resonance in C(ω). In the presence of a weak non-resonant microwave photon field in the low-dissipative resonator, the positions of dominant resonances depend on the number of photons, i.e. the collective ac Stark effect. Coupling of an SQA to the transmission line allows a straightforward experimental access of the collective states in microwave transmission experiments and, at the same time, to employ SQAs as sensitive single-photon detectors.