Charge-parity switching effects and optimisation of transmon-qubit design parameters

Abstract

Enhancing the performance of noisy quantum processors requires improving our understanding of error mechanisms and the ways to overcome them. In this study, we identify optimal ranges for qubit design parameters, grounded in comprehensive noise modeling. To this end, we also analyze a previously unexplored error mechanism that can perturb two-qubit gates due to charge-parity switches caused by quasiparticles. Due to the utilization of the higher levels of a transmon, where the charge dispersion is significantly larger, a charge-parity switch will affect the conditional phase of the two-qubit gate. We derive an analytical expression for the infidelity of a diabatic controlled-Z gate and see effects of similar magnitude in adiabatic controlled phase gates in the tunable coupler architecture. Moreover, we show that the effect of a charge-parity switch can be the dominant quasiparticle-related error source of a two-qubit gate. We also demonstrate that charge-parity switches induce a residual longitudinal interaction between qubits in a tunable-coupler circuit. We present a performance metric for quantum circuit execution, encompassing the fidelity and number of single and two-qubit gates in an algorithm, as well as the state preparation fidelity. This comprehensive metric, coupled with a detailed noise model, empowers us to determine an optimal range for the qubit design parameters Substantiating our findings through exact numerical simulations, we establish that fabricating quantum chips within this optimal parameter range not only augments the performance metric but also ensures its continued improvement with the enhancement of individual qubit coherence properties. Our systematic analysis offers insights and serves as a guiding framework for the development of the next generation of transmon-based quantum processors.

arXiv comment27 pages, 6 figures

References in corpus (80)

• Supplementary information for "Quantum supremacy using a programmable superconducting processor"
• Charge insensitive qubit design derived from the Cooper pair box
• Superconducting Qubits: Current State of Play
• Strong quantum computational advantage using a superconducting quantum processor
• Suppressing quantum errors by scaling a surface code logical qubit
• Simple pulses for elimination of leakage in weakly nonlinear qubits
• 1/f noise: implications for solid-state quantum information
• The Flux Qubit Revisited to Enhance Coherence and Reproducibility
• Schrieffer-Wolff transformation for quantum many-body systems
• Efficient Z-Gates for Quantum Computing
• New material platform for superconducting transmon qubits with coherence times exceeding 0.3 milliseconds
• Towards understanding two-level-systems in amorphous solids -- Insights from quantum circuits
• Scalable Noise Estimation with Random Unitary Operators
• A tunable coupling scheme for implementing high-fidelity two-qubit gates
• Transmon qubit with relaxation time exceeding 0.5 milliseconds
• Superconducting Quantum Computing: A Review
• Decoherence benchmarking of superconducting qubits
• Demonstrating a Continuous Set of Two-qubit Gates for Near-term Quantum Algorithms
• Probabilistic error cancellation with sparse Pauli-Lindblad models on noisy quantum processors
• Rapid high-fidelity multiplexed readout of superconducting qubits
• Correlated Charge Noise and Relaxation Errors in Superconducting Qubits
• Millisecond charge-parity fluctuations and induced decoherence in a superconducting qubit
• Relaxation and frequency shifts induced by quasiparticles in superconducting qubits
• Suppression of Qubit Crosstalk in a Tunable Coupling Superconducting Circuit
• Hot non-equilibrium quasiparticles in transmon qubits
• Laser-annealing Josephson junctions for yielding scaled-up superconducting quantum processors
• Quantum logic gates for coupled superconducting phase qubits
• High-fidelity, high-scalability two-qubit gate scheme for superconducting qubits
• Parametrically Activated Entangling Gates Using Transmon Qubits
• Resolving catastrophic error bursts from cosmic rays in large arrays of superconducting qubits
• Quasiparticle dynamics in granular aluminum close to the superconductor to insulator transition
• Protecting superconducting qubits from external sources of loss and heat
• Thermal and Residual Excited-State Population in a 3D Transmon Qubit
• Quantification and Characterization of Leakage Errors
• A fast, low-leakage, high-fidelity two-qubit gate for a programmable superconducting quantum computer
• Tunable Coupling Architecture for Fixed-frequency Transmons
• Quasiparticle relaxation of superconducting qubits in the presence of flux
• Randomized Benchmarking with Confidence
• Electric field spectroscopy of material defects in transmon qubits
• Reducing the impact of radioactivity on quantum circuits in a deep-underground facility
• Decoherence in qubits due to low-frequency noise
• Implementation of Conditional-Phase Gates based on tunable ZZ-Interactions
• Moving beyond the transmon: Noise-protected superconducting quantum circuits
• Measurements of Quasiparticle Tunneling Dynamics in a Bandgap-Engineered Transmon Qubit
• Characterizing and optimizing qubit coherence based on SQUID geometry
• Superconducting circuit protected by two-Cooper-pair tunneling
• Direct Dispersive Monitoring of Charge Parity in Offset-Charge-Sensitive Transmons
• Decoherence of superconducting qubits caused by quasiparticle tunneling
• Transmon platform for quantum computing challenged by chaotic fluctuations
• High-fidelity CZ gate for resonator-based superconducting quantum computers
• Scqubits: a Python package for superconducting qubits
• Normal-metal quasiparticle traps for superconducting qubits
• Floating tunable coupler for scalable quantum computing architectures
• Engineering superconducting qubits to reduce quasiparticles and charge noise
• Long-distance transmon coupler with CZ gate fidelity above $99.8\%$
• Universal fidelity reduction of quantum operations from weak dissipation
• Observation of Josephson Harmonics in Tunnel Junctions
• TLS Dynamics in a Superconducting Qubit Due to Background Ionizing Radiation
• Excitation of superconducting qubits from hot non-equilibrium quasiparticles
• Anomalous Charge Noise in Superconducting Qubits
• Bogoliubov Quasiparticles in Superconducting Qubits
• Optimizing quantum gates towards the scale of logical qubits
• Evolution of $1/f$ Flux Noise in Superconducting Qubits with Weak Magnetic Fields
• Quasiparticles in superconducting qubits with asymmetric junctions
• Distinguishing parity-switching mechanisms in a superconducting qubit
• Coupler-Assisted Controlled-Phase Gate with Enhanced Adiabaticity
• Double-Transmon Coupler: Fast Two-Qubit Gate with No Residual Coupling for Highly Detuned Superconducting Qubits
• Efficient quasiparticle traps with low dissipation through gap engineering
• Parity switching and decoherence by quasiparticles in single-junction transmons
• Randomized compiling for scalable quantum computing on a noisy superconducting quantum processor
• Tunable coupler to fully decouple and maximally localize superconducting qubits
• Optimal configurations for normal-metal traps in transmon qubits
• Proximity effect in normal-metal quasiparticle traps
• Identification of different types of high-frequency defects in superconducting qubits
• Realisation of adiabatic and diabatic CZ gates in superconducting qubits coupled with a tunable coupler
• Effective qubit dephasing induced by spectator-qubit relaxation
• Co-Design quantum simulation of nanoscale NMR
• Shape optimization of superconducting transmon qubit for low surface dielectric loss
• Quality, Speed, and Scale: three key attributes to measure the performance of near-term quantum computers
• Simulating noise on a quantum processor: interactions between a qubit and resonant two-level system bath

Cited by in corpus (4)

• Scalable Parameter Design for Superconducting Quantum Circuits with Graph Neural Networks
• Nonequilibrium regimes for quasiparticles in superconducting qubits with gap-asymmetric junctions
• Systematic Schrieffer-Wolff-transformation approach to Josephson junctions: quasiparticle effects and Josephson harmonics
• Hybrid quantum surface acoustic wave with skyrmion qubit for quantum information processing