Benchmarking the quality of multiplexed qubit readout beyond assignment fidelity
arXiv:2502.08589 · doi:10.1103/dpft-lxtx
Abstract
The accurate measurement of quantum two-level objects (qubits) is crucial for developing quantum computers. Over the last decade, the measure of choice for benchmarking readout routines for superconducting qubits has been assignment fidelity. However, this method only focuses on the preparation of computational basis states and therefore does not provide a complete characterization of the readout. Here, we expand the focus to the use of detector tomography to fully characterize multiqubit readout of superconducting transmon qubits. The impact of different readout parameters on the rate of information extraction is studied using quantum state reconstruction infidelity as a proxy. The results are then compared with assignment fidelities, showing good agreement for separable two-qubit states. We therefore propose the rate of infidelity convergence as a validation tool for assignment fidelity and a more comprehensive benchmark for single- and multiqubit readout optimization. To make the best use of experimental resources, we investigate the most efficient distribution of a limited shot budget between detector tomography and state reconstruction within the context of single- and two-qubit experiments. To address the growing interest in three-qubit gates and test scalability of the validation tool, we perform three-qubit quantum state tomography that goes beyond conventional readout-error-mitigation methods and find a factor of 30 reduction in quantum infidelity. Our results demonstrate that qubit readout correlations are not induced by a significantly reduced state distinguishability. Consequently, correlation coefficients can serve as a valuable tool in qubit readout optimization.
17 pages, 12 figures
References in corpus (35)
- Error mitigation for short-depth quantum circuits
- Suppressing quantum errors by scaling a surface code logical qubit
- Coherent Josephson qubit suitable for scalable quantum integrated circuits
- Quantum error correction below the surface code threshold
- Efficient variational quantum simulator incorporating active error minimisation
- A tunable coupling scheme for implementing high-fidelity two-qubit gates
- Measuring measurement
- Realizing Rapid, High-Fidelity, Single-Shot Dispersive Readout of Superconducting Qubits
- Iterative maximum-likelihood reconstruction in quantum homodyne tomography
- Rapid high-fidelity multiplexed readout of superconducting qubits
- Correlated Charge Noise and Relaxation Errors in Superconducting Qubits
- Mitigation of readout noise in near-term quantum devices by classical post-processing based on detector tomography
- Generating random density matrices
- Maximum-likelihood estimation of quantum measurement
- Leakage reduction in fast superconducting qubit gates via optimal control
- Quantum Overlapping Tomography
- Detector Tomography on IBM 5-qubit Quantum Computers and Mitigation of Imperfect Measurement
- Circuit QED with fluxonium qubits: theory of the dispersive regime
- High-fidelity three-qubit iToffoli gate for fixed-frequency superconducting qubits
- Frequency Division Multiplexing Readout and Simultaneous Manipulation of an Array of Flux Qubits
- TLS Dynamics in a Superconducting Qubit Due to Background Ionizing Radiation
- Experimental Adaptive Quantum Tomography of Two-Qubit States
- Efficient correction of multiqubit measurement errors
- Reducing leakage of single-qubit gates for superconducting quantum processors using analytical control pulse envelopes
- Error per single-qubit gate below in a superconducting qubit
- Extensive characterization of a family of efficient three-qubit gates at the coherence limit
- Modeling and mitigation of cross-talk effects in readout noise with applications to the Quantum Approximate Optimization Algorithm
- Single-Shot Readout of a Superconducting Qubit Using a Thermal Detector
- Coherent errors and readout errors in the surface code
- Cosmic-ray-induced correlated errors in superconducting qubit array
- Conditionally rigorous mitigation of multiqubit measurement errors
- Readout error mitigated quantum state tomography tested on superconducting qubits
- Operational Quantum Average-Case Distances
- Low-crosstalk bifurcation detectors for coupled flux qubits
- Mitigation of correlated readout errors without randomized measurements