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Main Authors: Ashhab, Sahel, Ao, Ziqiao, Yoshihara, Fumiki, Lupascu, Adrian, Semba, Kouichi
Format: Preprint
Published: 2023
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Online Access:https://arxiv.org/abs/2308.07849
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author Ashhab, Sahel
Ao, Ziqiao
Yoshihara, Fumiki
Lupascu, Adrian
Semba, Kouichi
author_facet Ashhab, Sahel
Ao, Ziqiao
Yoshihara, Fumiki
Lupascu, Adrian
Semba, Kouichi
contents We perform theoretical calculations to investigate the naturally occurring high-frequency cutoff in a circuit comprising a flux qubit coupled inductively to a transmission line resonator (TLR). Specifically, a decoupling occurs between the qubit and the high-frequency modes. The coupling strength between the qubit and resonator modes increases with mode frequency $ω$ as $\sqrtω$ at low frequencies and decreases as $1/\sqrtω$ at high frequencies. This result is similar to those of past studies that considered somewhat similar circuit designs. By avoiding the approximation of ignoring the qubit-TLR coupling in certain steps in the analysis, we obtain effects not captured in previous studies. In particular, we obtain a resonance effect that shifts the TLR mode frequencies close to qubit oscillation frequencies. We derive expressions for the TLR mode frequencies, qubit-TLR coupling strengths and qubit Lamb shift. We identify features in the spectrum of the system that can be used in future experiments to test and validate the theoretical model.
format Preprint
id arxiv_https___arxiv_org_abs_2308_07849
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle High-frequency suppression of inductive coupling between flux qubit and transmission line resonator
Ashhab, Sahel
Ao, Ziqiao
Yoshihara, Fumiki
Lupascu, Adrian
Semba, Kouichi
Quantum Physics
Superconductivity
We perform theoretical calculations to investigate the naturally occurring high-frequency cutoff in a circuit comprising a flux qubit coupled inductively to a transmission line resonator (TLR). Specifically, a decoupling occurs between the qubit and the high-frequency modes. The coupling strength between the qubit and resonator modes increases with mode frequency $ω$ as $\sqrtω$ at low frequencies and decreases as $1/\sqrtω$ at high frequencies. This result is similar to those of past studies that considered somewhat similar circuit designs. By avoiding the approximation of ignoring the qubit-TLR coupling in certain steps in the analysis, we obtain effects not captured in previous studies. In particular, we obtain a resonance effect that shifts the TLR mode frequencies close to qubit oscillation frequencies. We derive expressions for the TLR mode frequencies, qubit-TLR coupling strengths and qubit Lamb shift. We identify features in the spectrum of the system that can be used in future experiments to test and validate the theoretical model.
title High-frequency suppression of inductive coupling between flux qubit and transmission line resonator
topic Quantum Physics
Superconductivity
url https://arxiv.org/abs/2308.07849