Impact of Josephson junction array modes on fluxonium readout

Fuente: arXiv
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Hauptverfasser: Singh, Shraddha, Refael, Gil, Clerk, Aashish, Rosenfeld, Emma
Format: Preprint
Veröffentlicht: 2024
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author Singh, Shraddha
Refael, Gil
Clerk, Aashish
Rosenfeld, Emma
author_facet Singh, Shraddha
Refael, Gil
Clerk, Aashish
Rosenfeld, Emma
contents Dispersive readout of superconducting qubits is often limited by readout-drive-induced transitions between qubit levels. While there is a growing understanding of such effects in transmon qubits, the case of highly nonlinear fluxonium qubits is more complex. We theoretically analyze measurement-induced state transitions (MIST) during the dispersive readout of a fluxonium qubit. We focus on a new mechanism: a simultaneous transition/excitation involving the qubit and an internal mode of the Josephson junction array in the fluxonium circuit. Using an adiabatic Floquet approach, we show that these new kinds of MIST processes can be relevant when using realistic circuit parameters and relatively low readout drive powers. They also contribute to excess qubit dephasing even after a measurement is complete. In addition to outlining basic mechanisms, we also investigate the dependence of such transitions on the circuit parameters. We find that with a judicious choice of frequency allocations or coupling strengths, these parasitic processes can most likely be avoided.
format Preprint
id arxiv_https___arxiv_org_abs_2412_14788
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Impact of Josephson junction array modes on fluxonium readout
Singh, Shraddha
Refael, Gil
Clerk, Aashish
Rosenfeld, Emma
Mesoscale and Nanoscale Physics
Quantum Physics
Dispersive readout of superconducting qubits is often limited by readout-drive-induced transitions between qubit levels. While there is a growing understanding of such effects in transmon qubits, the case of highly nonlinear fluxonium qubits is more complex. We theoretically analyze measurement-induced state transitions (MIST) during the dispersive readout of a fluxonium qubit. We focus on a new mechanism: a simultaneous transition/excitation involving the qubit and an internal mode of the Josephson junction array in the fluxonium circuit. Using an adiabatic Floquet approach, we show that these new kinds of MIST processes can be relevant when using realistic circuit parameters and relatively low readout drive powers. They also contribute to excess qubit dephasing even after a measurement is complete. In addition to outlining basic mechanisms, we also investigate the dependence of such transitions on the circuit parameters. We find that with a judicious choice of frequency allocations or coupling strengths, these parasitic processes can most likely be avoided.
title Impact of Josephson junction array modes on fluxonium readout
topic Mesoscale and Nanoscale Physics
Quantum Physics
url https://arxiv.org/abs/2412.14788