Suppression of quasiparticle poisoning in transmon qubits by gap engineering

• URL: http://arxiv.org/abs/2309.02655v3
• Date: Mon, 13 May 2024 02:26:25 GMT
• Title: Suppression of quasiparticle poisoning in transmon qubits by gap engineering
• Authors: Plamen Kamenov, Thomas DiNapoli, Michael Gershenson, Srivatsan Chakram,
• Abstract summary: Inelastic quasiparticle tunneling across Josephson junctions in superconducting qubits results in decoherence and spurious excitations. We use "gap engineering" to suppress the tunneling of low-energy quasiparticles in Al-based transmon qubits. The suppression of QP tunneling also results in a reduction in the qubit energy relaxation rates.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: The performance of various superconducting devices operating at ultra-low temperatures is impaired by the presence of non-equilibrium quasiparticles. Inelastic quasiparticle (QP) tunneling across Josephson junctions in superconducting qubits results in decoherence and spurious excitations and, notably, can trigger correlated errors that severely impede quantum error correction. In this work, we use "gap engineering" to suppress the tunneling of low-energy quasiparticles in Al-based transmon qubits, a leading building block for superconducting quantum processors. By implementing potential barriers for QP, we strongly suppress QP tunneling across the junction and preserve charge parity for over $10^3$ seconds. The suppression of QP tunneling also results in a reduction in the qubit energy relaxation rates. The demonstrated approach to gap engineering can be easily implemented in all Al-based circuits with Josephson junctions.

Related papers

• Coupler-Assisted Leakage Reduction for Scalable Quantum Error Correction with Superconducting Qubits [18.641408987868154]
  leakage into non-computational states is a common issue in quantum systems including superconducting circuits. We propose and demonstrate a leakage reduction scheme utilizing tunable couplers, a widely adopted ingredient in large-scale superconducting quantum processors. We further reduce leakage to higher qubit levels with high efficiency (98.1%) and low error rate on the computational subspace (0.58%), suppressing time-correlated errors during QEC cycles.
  arXiv  Detail & Related papers  (2024-03-24T13:46:41Z)
• Resisting high-energy impact events through gap engineering in superconducting qubit arrays [2.118391560966808]
  High-energy impact events produce correlated errors in superconducting qubit arrays. Engineering different superconducting gaps across the qubit's Josephson junctions provides a method to resist this form of QP tunneling. By fabricating all-aluminum transmon qubits with both strong and weak gap engineering on the same substrate, we observe starkly different responses during high-energy impact events.
  arXiv  Detail & Related papers  (2024-02-23T23:03:11Z)
• Enhancing the Coherence of Superconducting Quantum Bits with Electric Fields [62.997667081978825]
  We show that qubit coherence can be improved by tuning defects away from the qubit resonance using an applied DC-electric field. We also discuss how local gate electrodes can be implemented in superconducting quantum processors to enable simultaneous in-situ coherence optimization of individual qubits.
  arXiv  Detail & Related papers  (2022-08-02T16:18:30Z)
• Space-time resolved quantum field approach to Klein tunneling dynamics across a finite barrier [0.0]
  We find that no particle actually tunnels through a finite supercritical barrier, even in the case of resonant tunneling. The transmission is instead mediated by modulations in pair production rates, at each edge of the barrier.
  arXiv  Detail & Related papers  (2022-05-30T14:13:15Z)
• 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)
• Quasiparticle tunneling as a probe of Josephson junction barrier and capacitor material in superconducting qubits [2.6549320605996862]
  Non-equilibrium quasiparticles are possible sources for decoherence in superconducting qubits because they can lead to energy decay or dephasing upon tunneling across Josephson junctions (JJs) Here, we investigate the impact of the intrinsic properties of two-dimensional transmon qubits on quasiparticle tunneling (QPT) We find the tunneling rate of the nonequilibrium quasiparticles to be sensitive to the choice of the shunting capacitor material and their geometry in qubits.
  arXiv  Detail & Related papers  (2021-06-22T02:33:59Z)
• Moving beyond the transmon: Noise-protected superconducting quantum circuits [55.49561173538925]
  superconducting circuits offer opportunities to store and process quantum information with high fidelity. Noise-protected devices constitute a new class of qubits in which the computational states are largely decoupled from local noise channels. This Perspective reviews the theoretical principles at the heart of these new qubits, describes recent experiments, and highlights the potential of robust encoding of quantum information in superconducting qubits.
  arXiv  Detail & Related papers  (2021-06-18T18:00:13Z)
• Probing the coherence of solid-state qubits at avoided crossings [51.805457601192614]
  We study the quantum dynamics of paramagnetic defects interacting with a nuclear spin bath at avoided crossings. The proposed theoretical approach paves the way to designing the coherence properties of spin qubits from first principles.
  arXiv  Detail & Related papers  (2020-10-21T15:37:59Z)
• Coherent superconducting qubits from a subtractive junction fabrication process [48.7576911714538]
  Josephson tunnel junctions are the centerpiece of almost any superconducting electronic circuit, including qubits. In recent years, sub-micron scale overlap junctions have started to attract attention. This work paves the way towards a more standardized process flow with advanced materials and growth processes, and constitutes an important step for large scale fabrication of superconducting quantum circuits.
  arXiv  Detail & Related papers  (2020-06-30T14:52:14Z)
• Universal non-adiabatic control of small-gap superconducting qubits [47.187609203210705]
  We introduce a superconducting composite qubit formed from two capacitively coupled transmon qubits. We control this low-frequency CQB using solely baseband pulses, non-adiabatic transitions, and coherent Landau-Zener interference. This work demonstrates that universal non-adiabatic control of low-frequency qubits is feasible using solely baseband pulses.
  arXiv  Detail & Related papers  (2020-03-29T22:48:34Z)
• Quantum emulation of coherent backscattering in a system of superconducting qubits [45.82374977939355]
  We use multi-pass Landau-Zener transitions at the avoided crossing of a highly-coherent superconducting qubit to emulate weak localization (WL) and universal conductance fluctuations (UCF) The higher coherence of this qubit enabled the realization of both effects, in contrast to earlier work arXiv:1204.6428, which successfully emulated UCF, but did not observe WL.
  arXiv  Detail & Related papers  (2019-12-28T17:11:53Z)

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.