Qubit assignment using time reversal
arXiv:2201.00445 · doi:10.1103/PRXQuantum.3.040333
Abstract
As the number of qubits available on noisy quantum computers grows, it will become necessary to efficiently select a subset of physical qubits to use in a quantum computation. For any given quantum program and device there are many ways to assign physical qubits for execution of the program, and assignments will differ in performance due to the variability in quality across qubits and entangling operations on a single device. Evaluating the performance of each assignment using fidelity estimation introduces significant experimental overhead and will be infeasible for many applications, while relying on standard device benchmarks provides incomplete information about the performance of any specific program. Furthermore, the number of possible assignments grows combinatorially in the number of qubits on the device and in the program, motivating the use of heuristic optimization techniques. We approach this problem using simulated annealing with a cost function based on the Loschmidt Echo, a diagnostic that measures the reversibility of a quantum process. We provide theoretical justification for this choice of cost function by demonstrating that the optimal qubit assignment coincides with the optimal qubit assignment based on state fidelity in the weak error limit, and we provide experimental justification using diagnostics performed on Google's superconducting qubit devices. We then establish the performance of simulated annealing for qubit assignment using classical simulations of noisy devices as well as optimization experiments performed on a quantum processor. Our results demonstrate that the use of Loschmidt Echoes and simulated annealing provides a scalable and flexible approach to optimizing qubit assignment on near-term hardware.
27 pages, 12 figures
References in corpus (22)
- Supplementary information for "Quantum supremacy using a programmable superconducting processor"
- Randomized Benchmarking of Quantum Gates
- Robust randomized benchmarking of quantum processes
- Direct Fidelity Estimation from Few Pauli Measurements
- Exponential suppression of bit or phase flip errors with repetitive error correction
- Realization of an Error-Correcting Surface Code with Superconducting Qubits
- Information Scrambling in Computationally Complex Quantum Circuits
- Scalable mitigation of measurement errors on quantum computers
- Measuring the Capabilities of Quantum Computers
- Toolbox for entanglement detection and fidelity estimation
- Removing leakage-induced correlated errors in superconducting quantum error correction
- Quantum Circuit Placement
- Optimal Layout Synthesis for Quantum Computing
- A Hardware-Aware Heuristic for the Qubit Mapping Problem in the NISQ Era
- Calibrated decoders for experimental quantum error correction
- Scalable randomized benchmarking of quantum computers using mirror circuits
- Accurately computing electronic properties of a quantum ring
- Full-Stack, Real-System Quantum Computer Studies: Architectural Comparisons and Design Insights
- Benchmarking near-term quantum computers via random circuit sampling
- Averaged circuit eigenvalue sampling
- On the learnability of quantum neural networks
- Qubit assignment using time reversal