Suppression of Quasiparticle Poisoning to $10^{-11}$ Levels in Superconducting Qubits via Infrared Shielding

• URL: http://arxiv.org/abs/2606.07339v1
• Date: Fri, 05 Jun 2026 14:51:12 GMT
• Title: Suppression of Quasiparticle Poisoning to $10^{-11}$ Levels in Superconducting Qubits via Infrared Shielding
• Abstract summary: We investigate quasiparticle poisoning in superconducting qubits under three infrared (IR) shielding.<n>We show a suppression of the switching rate by over four orders of magnitude via the implementation of improved shielding.<n>This represents the lowest quasiparticle density reported in the literature to date.
• Score: 1.0508605668588036
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Quasiparticle poisoning bottlenecks superconducting qubits, limiting coherence and the scalability of quantum processors. In this work, we systematically investigate quasiparticle poisoning in superconducting qubits under three infrared (IR) shielding configurations, ranging from a dedicated multi-layer design to a simplified implementation. By measuring quasiparticle-induced parity switching, we demonstrate a suppression of the switching rate by over four orders of magnitude via the implementation of improved shielding. In the best configuration, the rate decreases over time following cooldown and reaches 0.069$\,$Hz on day 34, corresponding to an anticipated quasiparticle density per Cooper pair of $1.88\times10^{-11}$. To our knowledge, this represents the lowest quasiparticle density reported in the literature to date. The remaining quasiparticle population is likely dominated by sporadic phonon bursts stemming from mechanical stress release in the on-chip films, as well as from the surrounding environment. The effective qubit temperature follows the phonon bath down to 17$\,$mK, enabling initialization errors of $\sim 0.01\%$ for 3$\,$GHz qubits. These results demonstrate that proper IR shielding and thermalization are essential for suppressing quasiparticle poisoning and enabling high-coherence, scalable superconducting qubit systems.

Related papers

• Achieving speedup in Dark Matter search experiments with a transmon-based NISQ algorithm [29.475562059710892]
  Coherent detection of ultralight bosonic dark matter can be achieved by monitoring slow Rabi oscillations in superconducting qubits.<n>We introduce an ancilla-assisted, gate-based protocol that enhances sensitivity to the hidden photon kinetic mixing parameter $$ using a single two-qubit gate.
  arXiv  Detail & Related papers  (2026-03-03T16:59:01Z)
• Recovery dynamics of a gap-engineered transmon after a quasiparticle burst [0.0]
  Ionizing radiation impacts create bursts of quasiparticle density in superconducting qubits.<n>These bursts temporarily degrade qubit coherence which can be detrimental for quantum error correction.<n>We experimentally resolve quasiparticle bursts in 3D gap-engineered transmon qubits by continuously monitoring qubit transitions.
  arXiv  Detail & Related papers  (2025-05-12T22:22:57Z)
• Quantifying Trapped Magnetic Vortex Losses in Niobium Resonators at mK Temperatures [0.0]
  Trapped magnetic vortices in niobium introduce microwave losses that degrade the performance of superconducting resonators.<n>Using a high-quality factor 3-D niobium cavity cooled through its superconducting transition in controlled magnetic fields, we isolate vortex-induced losses.<n>Results suggest that niobium-based transmon qubits can tolerate vortex-induced dissipation at trapped field levels up to several hundred mG.
  arXiv  Detail & Related papers  (2025-03-18T18:12:36Z)
• Millimeter-Wave Superconducting Qubit [39.76747788992184]
  A superconducting qubit is scaled up to the millimeter-wave range (near 100 GHz)<n>This has many advantages by removing the dependence on rare $3$He for refrigeration, simplifying cryogenic systems, and providing orders of magnitude higher cooling power.<n>This demonstration of a millimeter-wave quantum emitter offers exciting prospects for enhanced sensitivity thresholds in high-frequency photon detection.
  arXiv  Detail & Related papers  (2024-11-17T20:38:17Z)
• Unimon qubit [42.83899285555746]
  Superconducting qubits are one of the most promising candidates to implement quantum computers. Here, we introduce and demonstrate a superconducting-qubit type, the unimon, which combines the desired properties of high non-linearity, full insensitivity to dc charge noise, insensitivity to flux noise, and a simple structure consisting only of a single Josephson junction in a resonator.
  arXiv  Detail & Related papers  (2022-03-11T12:57:43Z)
• Engineering superconducting qubits to reduce quasiparticles and charge noise [14.613106897690752]
  We experimentally demonstrate how to control quasiparticle generation by downsizing the qubit. 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.
  arXiv  Detail & Related papers  (2022-02-03T06:40:21Z)
• Ultrafast renormalization of the onsite Coulomb repulsion in a cuprate superconductor [8.775772298435337]
  We use time-resolved x-ray absorption spectroscopy to demonstrate the light-induced renormalization of the Hubbard $U$ in a cuprate superconductor. We show that intense femtosecond laser pulses induce a substantial redshift of the upper Hubbard band, while leaving the Zhang-Rice singlet energy unaffected. Our demonstration of a dynamical Hubbard $U$ renormalization in a copper oxide paves the way to a novel strategy for the manipulation of superconductivity, magnetism, as well as to the realization of other long-range-ordered phases in light-driven quantum materials.
  arXiv  Detail & Related papers  (2021-09-27T17:59:42Z)
• Intrinsic mechanisms for drive-dependent Purcell decay in superconducting quantum circuits [68.8204255655161]
  We find that in a wide range of settings, the cavity-qubit detuning controls whether a non-zero photonic population increases or decreases qubit decay Purcell. Our method combines insights from a Keldysh treatment of the system, and Lindblad theory.
  arXiv  Detail & Related papers  (2021-06-09T16:21:31Z)
• Algorithmic Ground-state Cooling of Weakly-Coupled Oscillators using Quantum Logic [52.77024349608834]
  We introduce a novel algorithmic cooling protocol for transferring phonons from poorly- to efficiently-cooled modes. We demonstrate it experimentally by simultaneously bringing two motional modes of a Be$+$-Ar$13+$ mixed Coulomb crystal close to their zero-point energies. We reach the lowest temperature reported for a highly charged ion, with a residual temperature of only $Tlesssim200mathrmmu K$ in each of the two modes.
  arXiv  Detail & Related papers  (2021-02-24T17:46:15Z)
• Initial Design of a W-band Superconducting Kinetic Inductance Qubit (Kineticon) [0.0]
  We describe a kinetic inductance qubit operating at W-band frequencies with a nonlinear nanowire section. operating the qubits at higher frequencies may relax the dilution refrigerator temperature requirements.
  arXiv  Detail & Related papers  (2020-12-15T22:40:32Z)
• Impact of ionizing radiation on superconducting qubit coherence [43.13648171914508]
  We show that environmental radioactive materials and cosmic rays contribute to an elevated quasiparticle density that would limit superconducting qubits of the type measured here to coherence times in the millisecond regime. Introducing radiation shielding reduces the flux of ionizing radiation and positively correlates with increased coherence time.
  arXiv  Detail & Related papers  (2020-01-24T20:59:46Z)
• Optimal coupling of HoW$_{10}$ molecular magnets to superconducting circuits near spin clock transitions [85.83811987257297]
  We study the coupling of pure and magnetically diluted crystals of HoW$_10$ magnetic clusters to microwave superconducting coplanar waveguides. Results show that engineering spin-clock states of molecular systems offers a promising strategy to combine sizeable spin-photon interactions with a sufficient isolation from unwanted magnetic noise sources.
  arXiv  Detail & Related papers  (2019-11-18T11:03:06Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.