Resolving the positions of defects in superconducting quantum bits

Abstract

Solid-state quantum coherent devices are quickly progressing. Superconducting circuits, for instance, have already been used to demonstrate prototype quantum processors comprising a few tens of quantum bits. This development also revealed that a major part of decoherence and energy loss in such devices originates from a bath of parasitic material defects. However, neither the microscopic structure of defects nor the mechanisms by which they emerge during sample fabrication are understood. Here, we present a technique to obtain information on locations of defects relative to the thin film edge of the qubit circuit. Resonance frequencies of defects are tuned by exposing the qubit sample to electric fields generated by electrodes surrounding the chip. By determining the defect's coupling strength to each electrode and comparing it to a simulation of the field distribution, we obtain the probability at which location and at which interface the defect resides. This method is applicable to already existing samples of various qubit types, without further on-chip design changes. It provides a valuable tool for improving the material quality and nano-fabrication procedures towards more coherent quantum circuits.

References in corpus (19)

• Charge insensitive qubit design derived from the Cooper pair box
• Decoherence in Josephson Qubits from Dielectric Loss
• Coherent Josephson qubit suitable for scalable quantum integrated circuits
• Towards understanding two-level-systems in amorphous solids -- Insights from quantum circuits
• Decoherence in Josephson Qubits from Junction Resonances
• Surface participation and dielectric loss in superconducting qubits
• Fluctuations of Energy-Relaxation Times in Superconducting Qubits
• Decoherence benchmarking of superconducting qubits
• Observation of quantum oscillations between a Josephson phase qubit and a microscopic resonator using fast readout
• Correlating decoherence in transmon qubits: Low frequency noise by single fluctuators
• Observation of directly interacting coherent two-level systems in a solid
• Electric field spectroscopy of material defects in transmon qubits
• Origin and Suppression of $1/f$ Magnetic Flux Noise
• Characterization and Reduction of Capacitive Loss Induced by Sub-Micron Josephson Junction Fabrication in Superconducting Qubits
• Investigating surface loss effects in superconducting transmon qubits
• Direct identification of dilute surface spins on Al${}_2$O${}_3$: Origin of flux noise in quantum circuits
• Overlap junctions for high coherence superconducting qubits
• Suspending superconducting qubits by silicon micromachining
• Why phonon scattering in glasses is universally small at low temperatures

Cited by in corpus (31)

• Two-level systems in superconducting quantum devices due to trapped quasiparticles
• Gate-Tunable Transmon Using Selective-Area-Grown Superconductor-Semiconductor Hybrid Structures on Silicon
• In-situ bandaged Josephson junctions for superconducting quantum processors
• Disentangling the sources of ionizing radiation in superconducting qubits
• Identification of different types of high-frequency defects in superconducting qubits
• Non-Markovian Effects of Two-Level Systems in a Niobium Coaxial Resonator with a Single-Photon Lifetime of 10 ms
• Fabrication and surface treatment of electron-beam evaporated niobium for low-loss coplanar waveguide resonators
• Stabilizing and improving qubit coherence by engineering noise spectrum of two-level systems
• Effects of surface treatments on flux tunable transmon qubits
• Driven-state relaxation of a coupled qubit-defect system in spin-locking measurements
• Mitigating Losses of Superconducting Qubits Strongly Coupled to Defect Modes
• Observation of giant two-level systems in a granular superconductor
• Argon milling induced decoherence mechanisms in superconducting quantum circuits
• Fermion-Parity-Based Computation and its Majorana-Zero-Mode Implementation
• Acceptor-induced bulk dielectric loss in superconducting circuits on silicon
• Investigating microwave loss of SiGe using superconducting transmon qubits
• Investigation of the deposition of $\alpha$-tantalum (110) films on a-plane sapphire substrate by molecular beam epitaxy for superconducting circuit
• Stabilization of Qubit Relaxation Rates by Frequency Modulation
• Strain-spectroscopy of strongly interacting defects in superconducting qubits
• In-situ scanning gate imaging of individual two-level material defects in live superconducting quantum circuits
• Experimentally revealing anomalously large dipoles in a quantum-circuit dielectric
• Why Superconducting Ta Qubits Have Fewer Tunneling Two-Level Systems at the Air-Oxide Interface Than Nb Qubits
• Material matters in superconducting qubits
• Dynamical excitation control and multimode emission of an atom-photon bound state
• Snakes and Ladders: Adapting the surface code to defects
• Real-time adaptive tracking of fluctuating relaxation rates in superconducting qubits
• Quantum defects from single surface exhibit strong mutual interactions
• Disentangling the Impact of Quasiparticles and Two-Level Systems on the Statistics of Superconducting Qubit Lifetime
• Neural Network Based Qubit Environment Characterization
• A hybrid ferromagnetic transmon qubit: circuit design, feasibility and detection protocols for magnetic fluctuations
• Dynamic phases induced by two-level system defects on driven qubits