Quasiparticle effects in magnetic-field-resilient 3D transmons

Abstract

Recent research shows that quasiparticle-induced decoherence of superconducting qubits depends on the superconducting-gap asymmetry originating from the different thicknesses of the top and bottom films in Al/AlO${}_x$/Al junctions. Magnetic field is a key tuning knob to investigate this dependence as it can change the superconducting gaps in situ. We present measurements of the parity-switching time of a field-resilient 3D transmon with in-plane field up to 0.41T. At low fields, small parity splitting requires qutrit pulse sequences for parity measurements. We measure a non-monotonic evolution of the parity lifetime with in-plane magnetic field, increasing up to 0.2T, followed by a decrease at higher fields. We demonstrate that the superconducting-gap asymmetry plays a crucial role in the observed behavior. At zero field, the qubit frequency is nearly resonant with the superconducting-gap difference, favoring the energy exchange with the quasiparticles and so enhancing the parity-switching rate. With a higher magnetic field, the qubit frequency decreases and gets detuned from the gap difference, causing the initial increase of the parity lifetime, while photon-assisted qubit transitions increase, producing the subsequent decrease at higher fields. Besides giving a deeper insight into the parity-switching mechanism in conventional transmon qubits, we establish that Al-AlO${}_x$-Al JJs could be used in architectures for the parity-readout and manipulation of topological qubits based on Majorana zero modes.

References in corpus (28)

• Charge insensitive qubit design derived from the Cooper pair box
• QuTiP 2: A Python framework for the dynamics of open quantum systems
• Simple pulses for elimination of leakage in weakly nonlinear qubits
• New material platform for superconducting transmon qubits with coherence times exceeding 0.3 milliseconds
• Controlling the spontaneous emission of a superconducting transmon qubit
• Detecting bit-flip errors in a logical qubit using stabilizer measurements
• Measurement and Control of Quasiparticle Dynamics in a Superconducting Qubit
• Impact of ionizing radiation on superconducting qubit coherence
• Coherence and Decay of Higher Energy Levels of a Superconducting Transmon Qubit
• Resolving catastrophic error bursts from cosmic rays in large arrays of superconducting qubits
• Reducing the impact of radioactivity on quantum circuits in a deep-underground facility
• Suppressing relaxation in superconducting qubits by quasiparticle pumping
• Qutrit randomized benchmarking
• Non-Poissonian Quantum Jumps of a Fluxonium Qubit due to Quasiparticle Excitations
• Phonon traps reduce the quasiparticle density in superconducting circuits
• Engineering superconducting qubits to reduce quasiparticles and charge noise
• Observation of Josephson Harmonics in Tunnel Junctions
• Phonon downconversion to suppress correlated errors in superconducting qubits
• Environmental Radiation Impact on Lifetimes and Quasiparticle Tunneling Rates of Fixed-Frequency Transmon Qubits
• Bogoliubov Quasiparticles in Superconducting Qubits
• Kinetics of the superconducting charge qubit in the presence of a quasiparticle
• Coexistence of nonequilibrium density and equilibrium energy distribution of quasiparticles in a superconducting qubit
• Quasiparticles in superconducting qubits with asymmetric junctions
• Distinguishing parity-switching mechanisms in a superconducting qubit
• Magnetic-field resilience of 3D transmons with thin-film Al/AlO${}_x$/Al Josephson junctions approaching 1 T
• Magnetic-Field-Compatible Superconducting Transmon Qubit
• Nonequilibrium quasiparticle distribution in superconducting resonators: effect of pair-breaking photons
• A fast tunable 3D-transmon architecture for superconducting qubit-based hybrid devices

Cited by in corpus (6)

• Spin Environment of a Superconducting Qubit in High Magnetic Fields
• Offset Charge Dependence of Measurement-Induced Transitions in Transmons
• Nonequilibrium regimes for quasiparticles in superconducting qubits with gap-asymmetric junctions
• Quantum error mitigation in optimized circuits for particle-density correlations in real-time dynamics of the Schwinger model
• Charge Parity Rates in Transmon Qubits with Different Shunting Capacitors
• Magnetic-Field and Temperature Limits of a Kinetic-Inductance Traveling-Wave Parametric Amplifier