Berlin 2024 – scientific programme

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QI: Fachverband Quanteninformation

QI 16: Superconducting Qubits (joint session QI/TT)

QI 16.14: Talk

Wednesday, March 20, 2024, 13:00–13:15, HFT-FT 131

Renormalization effects in driven quantum phase slip junctions — •Christina Koliofoti and Roman-Pascal Riwar — Forschungszentrum Jülich, Peter Grünberg Institut (PGI-2), 52425 Jülich, Deutschland

Quantum circuit theory is a powerful tool to describe superconducting circuits. In its language, quantum phase slips (QPSs) are considered to be the exact dual to the Josephson effect. This duality renders the integration of QPS junctions into a unified theoretical framework challenging. As we argue, different existing formalisms may be inconsistent, and the correct inclusion of time-dependent flux driving requires introducing a large number of auxiliary, nonphysical degrees of freedom. We resolve these issues by describing QPS junctions as inductive rather than capacitive elements, and reducing the Hilbert space to account for a compact superconducting phase. Our treatment provides an approach to circuit quantization exclusively in terms of node-flux-node variables, and eliminates spurious degrees of freedom. In this talk we present in particular the possibility of a voltage-dependent renormalization of the QPS amplitude, by accounting for spatial variations of the electric field built up across the junction.

Keywords: Quantum circuit theory; Quantum phase slip junctions; Driven systems; Renormalization effects; Aharonov-Bohm/Aharonov-Casher effect