Readout error mitigated quantum state tomography tested on superconducting qubits

Abstract

Quantum technologies rely heavily on accurate control and reliable readout of quantum systems. Current experiments are limited by numerous sources of noise that can only be partially captured by simple analytical models and additional characterization of the noise sources is required. We test the ability of readout error mitigation to correct realistic noise found in systems composed of quantum two-level objects (qubits). To probe the limit of such methods, we designed a beyond-classical readout error mitigation protocol based on quantum state tomography (QST), which estimates the density matrix of a quantum system, and quantum detector tomography (QDT), which characterizes the measurement procedure. By treating readout error mitigation in the context of state tomography the method becomes largely readout mode-, architecture-, noise source-, and quantum state-independent. We implement this method on a superconducting qubit and evaluate the increase in reconstruction fidelity for QST. We characterize the performance of the method by varying important noise sources, such as suboptimal readout signal amplification, insufficient resonator photon population, off-resonant qubit drive, and effectively shortened $T_1$ and $T_2$ decay times. As a result, we identified noise sources for which readout error mitigation worked well, and observed decreases in readout infidelity by a factor of up to 30.

18 pages, 12 figures, corrections, title change and added additional information

References in corpus (48)

• Quantum Computing in the NISQ era and beyond
• Fault-tolerant quantum computation by anyons
• Polynomial-Time Algorithms for Prime Factorization and Discrete Logarithms on a Quantum Computer
• Quantum cryptography: Public key distribution and coin tossing
• Charge insensitive qubit design derived from the Cooper pair box
• A Quantum Engineer's Guide to Superconducting Qubits
• Topological quantum memory
• Superconducting Qubits: Current State of Play
• Error mitigation for short-depth quantum circuits
• Randomized Benchmarking of Quantum Gates
• Quantum Phases of Matter on a 256-Atom Programmable Quantum Simulator
• Experimental Quantum State Tomography of Optical Fields and Ultrafast Statistical Sampling
• Fault-tolerant quantum computation with high threshold in two dimensions
• Unknown Quantum States and Operations, a Bayesian View
• Non-local propagation of correlations in long-range interacting quantum systems
• Quantum computing for finance: overview and prospects
• Efficient variational quantum simulator incorporating active error minimisation
• Quantum Error Mitigation
• Hybrid quantum-classical algorithms and quantum error mitigation
• Induced measures in the space of mixed quantum states
• Optimal, reliable estimation of quantum states
• Measuring measurement
• Mitigating measurement errors in multi-qubit experiments
• Realizing Rapid, High-Fidelity, Single-Shot Dispersive Readout of Superconducting Qubits
• Iterative maximum-likelihood reconstruction in quantum homodyne tomography
• Mitigation of readout noise in near-term quantum devices by classical post-processing based on detector tomography
• Maximum-likelihood estimation of quantum measurement
• Adaptive Bayesian Quantum Tomography
• Quantum simulations of materials on near-term quantum computers
• Fundamental limits of quantum error mitigation
• Quantum Overlapping Tomography
• Detector Tomography on IBM 5-qubit Quantum Computers and Mitigation of Imperfect Measurement
• Systematic errors in current quantum state tomography tools
• Optimal full estimation of qubit mixed states
• Experimental Adaptive Quantum Tomography of Two-Qubit States
• Tomographic measurements on superconducting qubit states
• Efficient correction of multiqubit measurement errors
• Rigorous measurement error correction
• A hybrid quantum-classical approach to mitigating measurement errors
• Separable Measurement Estimation of Density Matrices and its Fidelity Gap with Collective Protocols
• Probing individual tunneling fluctuators with coherently controlled tunneling systems
• Enhancing the Coherence of Superconducting Quantum Bits with Electric Fields
• Experimental self-characterization of quantum measurements
• Adaptive quantum tomography of high-dimensional bipartite systems
• Efficient tomography with unknown detectors
• Towards practical Quantum Credit Risk Analysis
• When quantum state tomography benefits from willful ignorance
• Efficient reconstruction, benchmarking and validation of cross-talk models in readout noise in near-term quantum devices

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