Dephasing of a flux-qubit coupled to a harmonic oscillator

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dc.creatorBertet, P.
dc.creatorChiorescu, I.
dc.creatorHarmans, C. J. P. M
dc.creatorMooij, J. E.
dc.date2005-07-13
dc.date.accessioned2026-07-07T03:05:59Z
dc.date.available2026-07-07T03:05:59Z
dc.descriptionDecoherence in superconducting qubits is known to arise because of a variety of environmental degrees of freedom. In this article, we focus on the influence of thermal fluctuations in a weakly damped circuit resonance coupled to the qubit. Because of the coupling, the qubit frequency is shifted by an amount $n δν_0$ if the resonator contains $n$ energy quanta. Thermal fluctuations induce temporal variations $n(t)$ and thus dephasing. We give an approximate formula for the qubit dephasing time as a function of $δν_0$. We discuss the specific case of a flux-qubit coupled to the plasma mode of its DC-SQUID detector. We first derive a plasma mode-qubit interaction hamiltonian which, in addition to the usual Jaynes-Cummings term, has a coupling term quadratic in the oscillator variables coming from the flux-dependence of the SQUID Josephson inductance. Our model predicts that $δν_0$ cancels in certain non-trivial bias conditions for which dephasing due to thermal fluctuations should be suppressed.
dc.identifierhttps://arxiv.org/abs/cond-mat/0507290
dc.identifierhttp://arxiv.org/abs/cond-mat/0507290
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/26650
dc.subjectMesoscale and Nanoscale Physics
dc.subjectSuperconductivity
dc.titleDephasing of a flux-qubit coupled to a harmonic oscillator
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