Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1904.06290 · Physical Review Letters

Photon-Assisted Charge-Parity Jumps in a Superconducting Qubit

Manuel Houzet, Kyle Serniak, Gianluigi Catelani, Michel Devoret, L. I. Glazman

Published Sep 6, 2019• 64 citations
arXivHTMLPDF

Abstract

We evaluate the rates of energy and phase relaxation of a superconducting qubit caused by stray photons with energy exceeding the threshold for breaking a Cooper pair. All channels of relaxation within this mechanism are associated with the change in the charge parity of the qubit, enabling the separation of the photon-assisted processes from other contributions to the relaxation rates. Among the signatures of the new mechanism is the same order of rates of the transitions in which a qubit loses or gains energy, which is in agreement with recent experiments. Our theory offers the possibility to characterize the electromagnetic environment of superconducting devices at the single-photon level for frequencies above the superconducting gap.

DOI
10.1103/physrevlett.123.107704

Related papers

Distinguishing Parity-Switching Mechanisms in a Superconducting Qubit

Spencer Diamond, Valla Fatemi, Max Hays +8 more

Single-charge tunneling is a decoherence mechanism affecting superconducting qubits, yet the origin of excess quasiparticle excitations (QPs) responsible for this tunneling in superconducting devices is not fully understood.We measure the flux dependence of charge-parity (or, simply, "parity") switching in an offsetcharge-sensitive transmon qubit to identify the contributions of photon-assisted parity switching and QP generation to the overall parity-switching rate.The parity-switching rate exhibits a qubit-state-dependent peak in the flux dependence, indicating a cold distribution of excess QPs that are predominantly trapped in the low-gap film of the device.Moreover, we find that the photon-assisted process contributes significantly to both parity switching and the generation of excess QPs by fitting to a model that self-consistently incorporates photon-assisted parity switching as well as interfilm QP dynamics.

arXiv:2204.07458•PRX Quantum•Oct 10, 2022•42 citations

Multiphoton transitions between energy levels in a phase-biased Cooper-pair box

V. I. Shnyrkov, Th. Wagner, Detlef Born +5 more

We investigated both theoretically and experimentally dynamic features of a phase-biased charge qubit consisting of a single-Cooper-pair transistor closed by a superconducting loop. The effective inductance of the qubit was probed by a high-quality tank circuit. In the presence of a microwave power, with a frequency of the order of the qubit energy level separation, an alteration of the qubit inductance was observed. We demonstrate that this effect is caused by the redistribution of the qubit level population. The excitation of the qubit by one-, two-, and three-photon processes was detected. Quantitative agreement between theory and experimental data was found.

arXiv:cond-mat/0507583•Physical Review B•Jan 24, 2006•44 citations

Energy relaxation of a superconducting charge qubit via Andreev processes

Roman M. Lutchyn, L. I. Glazman

We study fundamental limitations on the energy relaxation rate of a superconducting charge qubit with a large-gap Cooper-pair box, ${\ensuremath{\Delta}}_{b}>{\ensuremath{\Delta}}_{r}$. At a sufficiently large mismatch between the gap energies in the box ${\ensuremath{\Delta}}_{b}$ and in the reservoir ${\ensuremath{\Delta}}_{r}$, ``quasiparticle poisoning" becomes ineffective even in the presence of nonequilibrium quasiparticles in the reservoir. The qubit relaxation still may occur due to higher-order (Andreev) processes. In this paper, we evaluate the qubit energy relaxation rate ${T\phantom{\rule{0.2em}{0ex}}}_{1}^{\ensuremath{-}1}$ due to Andreev processes.

arXiv:0706.0522•Physical Review B•Sep 11, 2007•1 citation

Charge Qubit Coupled to an Intense Microwave Electromagnetic Field in a Superconducting Nb Device: Evidence for Photon-Assisted Quasiparticle Tunneling

Sebastian E. de Graaf, Juha Leppäkangas, A. A. Adamyan +6 more

We study a superconducting charge qubit coupled to an intensive electromagnetic field and probe changes in the resonance frequency of the formed dressed states. At large driving strengths, exceeding the qubit energy-level splitting, this reveals the well known Landau-Zener-Stückelberg interference structure of a longitudinally driven two-level system. For even stronger drives, we observe a significant change in the Landau-Zener-Stückelberg pattern and contrast. We attribute this to photon-assisted quasiparticle tunneling in the qubit. This results in the recovery of the qubit parity, eliminating effects of quasiparticle poisoning, and leads to an enhanced interferometric response. The interference pattern becomes robust to quasiparticle poisoning and has a good potential for accurate charge sensing.

arXiv:1306.4465•Physical Review Letters•Sep 26, 2013•28 citations

Photon-assisted phase slips in superconducting nanowires

Biao Zhang, Labao Zhang, Rui Ge +11 more

The intrinsic mechanism of absorbing photons in superconductors reveals the interaction between photons and Cooper pairs, which is of great significance for developing new superconducting nanowire single photon detectors (SNSPDs). Here we propose a photon-assisted phase slip model to describe the interaction mechanism between photons and superconductors. In this model, incident photons destroy large quantities of Cooper pairs and reduce the free-energy barrier of the phase slip, resulting in proliferation in the phase slip events and leading to superconducting transition. The switching rates from the superconducting state of a niobium nitride nanowire under various photon irradiation and temperatures are calculated through the distribution of switching currents in the experiment. The experimental data can be well fitted by our deduced expression of phase slip rate after eliminating the influence of external noise.

Optoelectronic devices and integration. Conference•Oct 15, 2021•1 citation

Engineering superconducting qubits to reduce quasiparticles and charge noise

Xianchuang Pan, Yuxuan Zhou, Haolan Yuan +10 more

Identifying, quantifying, and suppressing decoherence mechanisms in qubits are important steps towards the goal of engineering a quantum computer or simulator. Superconducting circuits offer flexibility in qubit design; however, their performance is adversely affected by quasiparticles (broken Cooper pairs). Developing a quasiparticle mitigation strategy compatible with scalable, high-coherence devices is therefore highly desirable. Here we experimentally demonstrate how to control quasiparticle generation by downsizing the qubit, capping it with a metallic cover, and equipping it with suitable quasiparticle traps. Using a flip-chip design, we shape the electromagnetic environment of the qubit above the superconducting gap, inhibiting quasiparticle poisoning. Our findings support the hypothesis that quasiparticle generation is dominated by the breaking of Cooper pairs at the junction, as a result of photon absorption by the antenna-like qubit structure. We achieve record low charge-parity switching rate (<1 Hz). Our aluminium devices also display improved stability with respect to discrete charging events.

arXiv:2202.01435•Nature Communications•Nov 23, 2022•70 citations
We evaluate the rates of energy and phase relaxation of a superconducting qubit caused by stray photons with energy exceeding the threshold for breaking a Cooper pair. All channels of relaxation within this mechanism are associated with the change in the charge parity of the qubit, enabling the separation of the photon-assisted processes from other contributions to the relaxation rates. Among the signatures of the new mechanism is the same order of rates of the transitions in which a qubit loses or gains energy, which is in agreement with recent experiments. Our theory offers the possibility to characterize the electromagnetic environment of superconducting devices at the single-photon level for frequencies above the superconducting gap.
Single-charge tunneling is a decoherence mechanism affecting superconducting qubits, yet the origin of excess quasiparticle excitations (QPs) responsible for this tunneling in superconducting devices is not fully understood.We measure the flux dependence of charge-parity (or, simply, "parity") switching in an offsetcharge-sensitive transmon qubit to identify the contributions of photon-assisted parity switching and QP generation to the overall parity-switching rate.The parity-switching rate exhibits a qubit-state-dependent peak in the flux dependence, indicating a cold distribution of excess QPs that are predominantly trapped in the low-gap film of the device.Moreover, we find that the photon-assisted process contributes significantly to both parity switching and the generation of excess QPs by fitting to a model that self-consistently incorporates photon-assisted parity switching as well as interfilm QP dynamics.
We investigated both theoretically and experimentally dynamic features of a phase-biased charge qubit consisting of a single-Cooper-pair transistor closed by a superconducting loop. The effective inductance of the qubit was probed by a high-quality tank circuit. In the presence of a microwave power, with a frequency of the order of the qubit energy level separation, an alteration of the qubit inductance was observed. We demonstrate that this effect is caused by the redistribution of the qubit level population. The excitation of the qubit by one-, two-, and three-photon processes was detected. Quantitative agreement between theory and experimental data was found.
We study fundamental limitations on the energy relaxation rate of a superconducting charge qubit with a large-gap Cooper-pair box, ${\ensuremath{\Delta}}_{b}>{\ensuremath{\Delta}}_{r}$. At a sufficiently large mismatch between the gap energies in the box ${\ensuremath{\Delta}}_{b}$ and in the reservoir ${\ensuremath{\Delta}}_{r}$, ``quasiparticle poisoning" becomes ineffective even in the presence of nonequilibrium quasiparticles in the reservoir. The qubit relaxation still may occur due to higher-order (Andreev) processes. In this paper, we evaluate the qubit energy relaxation rate ${T\phantom{\rule{0.2em}{0ex}}}_{1}^{\ensuremath{-}1}$ due to Andreev processes.
We study a superconducting charge qubit coupled to an intensive electromagnetic field and probe changes in the resonance frequency of the formed dressed states. At large driving strengths, exceeding the qubit energy-level splitting, this reveals the well known Landau-Zener-Stückelberg interference structure of a longitudinally driven two-level system. For even stronger drives, we observe a significant change in the Landau-Zener-Stückelberg pattern and contrast. We attribute this to photon-assisted quasiparticle tunneling in the qubit. This results in the recovery of the qubit parity, eliminating effects of quasiparticle poisoning, and leads to an enhanced interferometric response. The interference pattern becomes robust to quasiparticle poisoning and has a good potential for accurate charge sensing.
The intrinsic mechanism of absorbing photons in superconductors reveals the interaction between photons and Cooper pairs, which is of great significance for developing new superconducting nanowire single photon detectors (SNSPDs). Here we propose a photon-assisted phase slip model to describe the interaction mechanism between photons and superconductors. In this model, incident photons destroy large quantities of Cooper pairs and reduce the free-energy barrier of the phase slip, resulting in proliferation in the phase slip events and leading to superconducting transition. The switching rates from the superconducting state of a niobium nitride nanowire under various photon irradiation and temperatures are calculated through the distribution of switching currents in the experiment. The experimental data can be well fitted by our deduced expression of phase slip rate after eliminating the influence of external noise.
Identifying, quantifying, and suppressing decoherence mechanisms in qubits are important steps towards the goal of engineering a quantum computer or simulator. Superconducting circuits offer flexibility in qubit design; however, their performance is adversely affected by quasiparticles (broken Cooper pairs). Developing a quasiparticle mitigation strategy compatible with scalable, high-coherence devices is therefore highly desirable. Here we experimentally demonstrate how to control quasiparticle generation by downsizing the qubit, capping it with a metallic cover, and equipping it with suitable quasiparticle traps. Using a flip-chip design, we shape the electromagnetic environment of the qubit above the superconducting gap, inhibiting quasiparticle poisoning. Our findings support the hypothesis that quasiparticle generation is dominated by the breaking of Cooper pairs at the junction, as a result of photon absorption by the antenna-like qubit structure. We achieve record low charge-parity switching rate (<1 Hz). Our aluminium devices also display improved stability with respect to discrete charging events.