Tunneling of fluxons via a Josephson resonant level

Fuente: arXiv
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Main Authors: Vakhtel, T., Kurilovich, P. D., Pita-Vidal, M., Bargerbos, A., Fatemi, V., van Heck, B.
Format: Preprint
Published: 2023
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author Vakhtel, T.
Kurilovich, P. D.
Pita-Vidal, M.
Bargerbos, A.
Fatemi, V.
van Heck, B.
author_facet Vakhtel, T.
Kurilovich, P. D.
Pita-Vidal, M.
Bargerbos, A.
Fatemi, V.
van Heck, B.
contents Fluxons in a superconducting loop can be coherently coupled by quantum phase slips occurring at a weak link such as a Josephson junction. If Cooper pair tunneling at the junction occurs through a resonant level, $2π$ quantum phase slips are suppressed, and fluxons are predominantly coupled by $4π$ quantum phase slips. We analyze this scenario by computing the coupling between fluxons as the level is brought into resonance with the superconducting condensate. The results indicate that the $4π$-dominated regime can be observed directly in the transition spectrum for circuit parameters typical of a fluxonium qubit. We also show that, if the inductive energy of the loop is much smaller than the plasma frequency of the junction, the low-energy Hamiltonian of the circuit is dual to that of a topological superconducting island. These findings can inform experiments on bifluxon qubits as well as the design of novel types of protected qubits.
format Preprint
id arxiv_https___arxiv_org_abs_2310_03102
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Tunneling of fluxons via a Josephson resonant level
Vakhtel, T.
Kurilovich, P. D.
Pita-Vidal, M.
Bargerbos, A.
Fatemi, V.
van Heck, B.
Mesoscale and Nanoscale Physics
Superconductivity
Quantum Physics
Fluxons in a superconducting loop can be coherently coupled by quantum phase slips occurring at a weak link such as a Josephson junction. If Cooper pair tunneling at the junction occurs through a resonant level, $2π$ quantum phase slips are suppressed, and fluxons are predominantly coupled by $4π$ quantum phase slips. We analyze this scenario by computing the coupling between fluxons as the level is brought into resonance with the superconducting condensate. The results indicate that the $4π$-dominated regime can be observed directly in the transition spectrum for circuit parameters typical of a fluxonium qubit. We also show that, if the inductive energy of the loop is much smaller than the plasma frequency of the junction, the low-energy Hamiltonian of the circuit is dual to that of a topological superconducting island. These findings can inform experiments on bifluxon qubits as well as the design of novel types of protected qubits.
title Tunneling of fluxons via a Josephson resonant level
topic Mesoscale and Nanoscale Physics
Superconductivity
Quantum Physics
url https://arxiv.org/abs/2310.03102