Decay of transmon qubit in a broadband one-dimensional cavity

Fuente: arXiv
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Autores principales: Greenberg, Ya. S., Shtygashev, A. A., Kibis, O. V.
Formato: Preprint
Publicado: 2025
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author Greenberg, Ya. S.
Shtygashev, A. A.
Kibis, O. V.
author_facet Greenberg, Ya. S.
Shtygashev, A. A.
Kibis, O. V.
contents We investigate the decay dynamics of a three-level artificial atom, a superconducting transmon qubit, weakly coupled to a continuum of modes in a broadband, one-dimensional cavity. Using the resolvent formalism, we derive analytical expressions for the resonance frequency shifts and widths, which are then evaluated numerically for a Gaussian density of states. We identify two distinct dynamical regimes, differentiated by the ratio of the qubit's coupling strength to the continuum bandwidth. When this ratio is much less than one, the system exhibits a Markovian regime in which the resonance width is practically independent of energy within the continuum band. As the ratio increases, the system transitions to a non-Markovian regime where the resonance width becomes strongly energy-dependent. In this regime, the qubit interacts with the continuum faster than the continuum can erase the information from the qubit's past. Furthermore, we demonstrate that the coupling between the transmon's second level and its ground state significantly influences the decay dynamics of the third level. The interaction between these two levels opens a fast two-photon decay channel, which broadens the transmon's second level.
format Preprint
id arxiv_https___arxiv_org_abs_2511_02350
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Decay of transmon qubit in a broadband one-dimensional cavity
Greenberg, Ya. S.
Shtygashev, A. A.
Kibis, O. V.
Quantum Physics
Mesoscale and Nanoscale Physics
We investigate the decay dynamics of a three-level artificial atom, a superconducting transmon qubit, weakly coupled to a continuum of modes in a broadband, one-dimensional cavity. Using the resolvent formalism, we derive analytical expressions for the resonance frequency shifts and widths, which are then evaluated numerically for a Gaussian density of states. We identify two distinct dynamical regimes, differentiated by the ratio of the qubit's coupling strength to the continuum bandwidth. When this ratio is much less than one, the system exhibits a Markovian regime in which the resonance width is practically independent of energy within the continuum band. As the ratio increases, the system transitions to a non-Markovian regime where the resonance width becomes strongly energy-dependent. In this regime, the qubit interacts with the continuum faster than the continuum can erase the information from the qubit's past. Furthermore, we demonstrate that the coupling between the transmon's second level and its ground state significantly influences the decay dynamics of the third level. The interaction between these two levels opens a fast two-photon decay channel, which broadens the transmon's second level.
title Decay of transmon qubit in a broadband one-dimensional cavity
topic Quantum Physics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2511.02350