Regensburg 2025 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 11: Superconductivity: Poster

TT 11.30: Poster

Monday, March 17, 2025, 15:00–18:00, P4

Building a Quantum Wheatstone Bridge — •Thilo Krumrey¹, Alex Kreuzer¹, Hossam Tohamy¹, Hannes Rotzinger^1,2, and Alexey V. Ustinov^1,2 — ¹Physikalisches Institut, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany — ²IQMT, Karlsruher Institut für Technologie, 76131 Karlsruhe, Germany

Today’s qubits, while still quite noisy, are sufficiently coherent for non-computing applications. We are exploring the possibility of using an arrangement of superconducting qubits to study the quantum version of the Wheatstone resistance bridge[1]. It would allow for comparative measurements of coupling energies using the interference of an excitation gradient across strongly coupled qubits. We propose an implementation of a quantum Wheatstone bridge using superconducting quantum circuits with quarton flux qubits. Here, the large positive anharmonicity and the tunability [2] of the operating frequency are beneficial for our application. We will present circuit simulations results based on the proposed design and compare them with measurements of the circuit at mK temperatures.

[1] K. Poulsen et al., PRL 128, 240401 (2022).

[2] F. Yan et al., arXiv:2006.04130v1.

Keywords: Flux Qubits; Quartic Potential; Quantum Circuit