The perfect entangler spectrum as a tool to analyze crosstalk

Abstract

Crosstalk is a key obstacle to scaling up quantum computers. It may arise from persistent qubit-qubit couplings or dynamically during gate operation, with the latter being particularly difficult to detect. Here, we introduce the perfect entangler spectrum as a means to identify dynamic crosstalk leading to undesired entanglement. It leverages the geometric classification of two-qubit gates in terms of perfect entanglers. We exemplify application of the spectroscopy for fixed-frequency transmons and parametrically driven gates: When scanning the frequency of a spectator qubit, peaks in the perfect entangler spectrum signal dynamic crosstalk, and analysis of the peaks reveals the mechanisms causing the crosstalk. We discuss the experimental implementation of the crosstalk spectroscopy which requires two two-qubit gate tomographies.

References in corpus (45)

• Supplementary information for "Quantum supremacy using a programmable superconducting processor"
• Charge insensitive qubit design derived from the Cooper pair box
• Coupling Superconducting Qubits via a Cavity Bus
• Suppressing quantum errors by scaling a surface code logical qubit
• A geometric theory of non-local two-qubit operations
• A tunable coupling scheme for implementing high-fidelity two-qubit gates
• Nonlocal properties of two-qubit gates and mixed states and optimization of quantum computations
• Characterization of addressability by simultaneous randomized benchmarking
• A universal gate for fixed-frequency qubits via a tunable bus
• Demonstration of Universal Parametric Entangling Gates on a Multi-Qubit Lattice
• Realization of high-fidelity CZ and ZZ-free iSWAP gates with a tunable coupler
• Suppression of Qubit Crosstalk in a Tunable Coupling Superconducting Circuit
• Detecting crosstalk errors in quantum information processors
• Parametrically Activated Entangling Gates Using Transmon Qubits
• Tunable Coupling Architecture for Fixed-frequency Transmons
• Demonstration of a High-Fidelity CNOT for Fixed-Frequency Transmons with Engineered ZZ Suppression
• Three Qubit Randomized Benchmarking
• High-Fidelity, Frequency-Flexible Two-Qubit Fluxonium Gates with a Transmon Coupler
• First-principles analysis of cross-resonance gate operation
• Parametric coupling for superconducting qubits
• High fidelity two-qubit gates on fluxoniums using a tunable coupler
• Quantum crosstalk analysis for simultaneous gate operations on superconducting qubits
• Two-qubit spectroscopy of spatiotemporally correlated quantum noise in superconducting qubits
• Two-qubit entangling gates within arbitrarily long chains of trapped ions
• Parametric-resonance entangling gates with a tunable coupler
• Benchmarking the noise sensitivity of different parametric two-qubit gates in a single superconducting quantum computing platform
• Benchmarking Coherent Errors in Controlled-Phase Gates due to Spectator Qubits
• Quantum Crosstalk Robust Quantum Control
• Methods for Measuring Magnetic Flux Crosstalk Between Tunable Transmons
• Crosstalk Suppression for Fault-tolerant Quantum Error Correction with Trapped Ions
• Optimizing for an arbitrary perfect entangler: I. Functionals
• Optimizing for an arbitrary perfect entangler. II. Application
• Perturbation impact of spectators on a cross-resonance gate in a tunable coupling superconducting circuit
• Accurate methods for the analysis of strong-drive effects in parametric gates
• Characterizing crosstalk of superconducting transmon processors
• Signal crosstalk in a flip-chip quantum processor
• Tunable coupler to fully decouple and maximally localize superconducting qubits
• Estimating gate-set properties from random sequences
• Crosstalk-Robust Quantum Control in Multimode Bosonic Systems
• Tensor network noise characterization for near-term quantum computers
• Cross-talk in superconducting qubit lattices with tunable couplers -- comparing transmon and fluxonium architectures
• Parametric multi-element coupling architecture for coherent and dissipative control of superconducting qubits
• Scalable Parameter Design for Superconducting Quantum Circuits with Graph Neural Networks
• Characterization and Optimization of Tunable Couplers via Adiabatic Control in Superconducting Circuits
• Theory of quasiparticle generation by microwave drives in superconducting qubits