Hamiltonian of a flux qubit-LC oscillator circuit in the deep–strong-coupling regime

<div><p>We derive the Hamiltonian of a superconducting circuit that comprises a single-Josephson-junction flux qubit inductively coupled to an LC oscillator, and we compare the derived circuit Hamiltonian with the quantum Rabi Hamiltonian, which describes a two-level system coupled to a...

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المؤلف الرئيسي: F. Yoshihara (18387177) (author)
مؤلفون آخرون: S. Ashhab (14152701) (author), T. Fuse (18387180) (author), M. Bamba (18387183) (author), K. Semba (18387186) (author)
منشور في: 2022
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author F. Yoshihara (18387177)
author2 S. Ashhab (14152701)
T. Fuse (18387180)
M. Bamba (18387183)
K. Semba (18387186)
author2_role author
author
author
author
author_facet F. Yoshihara (18387177)
S. Ashhab (14152701)
T. Fuse (18387180)
M. Bamba (18387183)
K. Semba (18387186)
author_role author
dc.creator.none.fl_str_mv F. Yoshihara (18387177)
S. Ashhab (14152701)
T. Fuse (18387180)
M. Bamba (18387183)
K. Semba (18387186)
dc.date.none.fl_str_mv 2022-04-26T03:00:00Z
dc.identifier.none.fl_str_mv 10.1038/s41598-022-10203-1
dc.relation.none.fl_str_mv https://figshare.com/articles/journal_contribution/Hamiltonian_of_a_flux_qubit-LC_oscillator_circuit_in_the_deep_strong-coupling_regime/25611663
dc.rights.none.fl_str_mv CC BY 4.0
info:eu-repo/semantics/openAccess
dc.subject.none.fl_str_mv Physical sciences
Quantum physics
Flux qubit
LC oscillator
Circuit Hamiltonian
Two-level system
Harmonic oscillator
Energy level structure
Coupling strength
dc.title.none.fl_str_mv Hamiltonian of a flux qubit-LC oscillator circuit in the deep–strong-coupling regime
dc.type.none.fl_str_mv Text
Journal contribution
info:eu-repo/semantics/publishedVersion
text
contribution to journal
description <div><p>We derive the Hamiltonian of a superconducting circuit that comprises a single-Josephson-junction flux qubit inductively coupled to an LC oscillator, and we compare the derived circuit Hamiltonian with the quantum Rabi Hamiltonian, which describes a two-level system coupled to a harmonic oscillator. We show that there is a simple, intuitive correspondence between the circuit Hamiltonian and the quantum Rabi Hamiltonian. While there is an overall shift of the entire spectrum, the energy level structure of the circuit Hamiltonian up to the seventh excited states can still be fitted well by the quantum Rabi Hamiltonian even in the case where the coupling strength is larger than the frequencies of the qubit and the oscillator, i.e., when the qubit-oscillator circuit is in the deep–strong-coupling regime. We also show that although the circuit Hamiltonian can be transformed via a unitary transformation to a Hamiltonian containing a capacitive coupling term, the resulting circuit Hamiltonian cannot be approximated by the variant of the quantum Rabi Hamiltonian that is obtained using an analogous procedure for mapping the circuit variables onto Pauli and harmonic oscillator operators, even for relatively weak coupling. This difference between the flux and charge gauges follows from the properties of the qubit Hamiltonian eigenstates.</p><p> </p></div><h2>Other Information</h2> <p> Published in: Scientific Reports<br> License: <a href="https://creativecommons.org/licenses/by/4.0" target="_blank">https://creativecommons.org/licenses/by/4.0</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1038/s41598-022-10203-1" target="_blank">https://dx.doi.org/10.1038/s41598-022-10203-1</a></p>
eu_rights_str_mv openAccess
id Manara2_70f3548f33d6b98e535d10cb1ac29065
identifier_str_mv 10.1038/s41598-022-10203-1
network_acronym_str Manara2
network_name_str Manara2
oai_identifier_str oai:figshare.com:article/25611663
publishDate 2022
repository.mail.fl_str_mv
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rights_invalid_str_mv CC BY 4.0
spelling Hamiltonian of a flux qubit-LC oscillator circuit in the deep–strong-coupling regimeF. Yoshihara (18387177)S. Ashhab (14152701)T. Fuse (18387180)M. Bamba (18387183)K. Semba (18387186)Physical sciencesQuantum physicsFlux qubitLC oscillatorCircuit HamiltonianTwo-level systemHarmonic oscillatorEnergy level structureCoupling strength<div><p>We derive the Hamiltonian of a superconducting circuit that comprises a single-Josephson-junction flux qubit inductively coupled to an LC oscillator, and we compare the derived circuit Hamiltonian with the quantum Rabi Hamiltonian, which describes a two-level system coupled to a harmonic oscillator. We show that there is a simple, intuitive correspondence between the circuit Hamiltonian and the quantum Rabi Hamiltonian. While there is an overall shift of the entire spectrum, the energy level structure of the circuit Hamiltonian up to the seventh excited states can still be fitted well by the quantum Rabi Hamiltonian even in the case where the coupling strength is larger than the frequencies of the qubit and the oscillator, i.e., when the qubit-oscillator circuit is in the deep–strong-coupling regime. We also show that although the circuit Hamiltonian can be transformed via a unitary transformation to a Hamiltonian containing a capacitive coupling term, the resulting circuit Hamiltonian cannot be approximated by the variant of the quantum Rabi Hamiltonian that is obtained using an analogous procedure for mapping the circuit variables onto Pauli and harmonic oscillator operators, even for relatively weak coupling. This difference between the flux and charge gauges follows from the properties of the qubit Hamiltonian eigenstates.</p><p> </p></div><h2>Other Information</h2> <p> Published in: Scientific Reports<br> License: <a href="https://creativecommons.org/licenses/by/4.0" target="_blank">https://creativecommons.org/licenses/by/4.0</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1038/s41598-022-10203-1" target="_blank">https://dx.doi.org/10.1038/s41598-022-10203-1</a></p>2022-04-26T03:00:00ZTextJournal contributioninfo:eu-repo/semantics/publishedVersiontextcontribution to journal10.1038/s41598-022-10203-1https://figshare.com/articles/journal_contribution/Hamiltonian_of_a_flux_qubit-LC_oscillator_circuit_in_the_deep_strong-coupling_regime/25611663CC BY 4.0info:eu-repo/semantics/openAccessoai:figshare.com:article/256116632022-04-26T03:00:00Z
spellingShingle Hamiltonian of a flux qubit-LC oscillator circuit in the deep–strong-coupling regime
F. Yoshihara (18387177)
Physical sciences
Quantum physics
Flux qubit
LC oscillator
Circuit Hamiltonian
Two-level system
Harmonic oscillator
Energy level structure
Coupling strength
status_str publishedVersion
title Hamiltonian of a flux qubit-LC oscillator circuit in the deep–strong-coupling regime
title_full Hamiltonian of a flux qubit-LC oscillator circuit in the deep–strong-coupling regime
title_fullStr Hamiltonian of a flux qubit-LC oscillator circuit in the deep–strong-coupling regime
title_full_unstemmed Hamiltonian of a flux qubit-LC oscillator circuit in the deep–strong-coupling regime
title_short Hamiltonian of a flux qubit-LC oscillator circuit in the deep–strong-coupling regime
title_sort Hamiltonian of a flux qubit-LC oscillator circuit in the deep–strong-coupling regime
topic Physical sciences
Quantum physics
Flux qubit
LC oscillator
Circuit Hamiltonian
Two-level system
Harmonic oscillator
Energy level structure
Coupling strength