Efficient Experimental Verification of Quantum Gates with Local Operations

Abstract

Verifying the correct functioning of quantum gates is a crucial step towards reliable quantum information processing, but it becomes an overwhelming challenge as the system size grows due to the dimensionality curse. Recent theoretical breakthroughs show that it is possible to verify various important quantum gates with the optimal sample complexity of $O(1/\epsilon )$ using local operations only, where $\epsilon$ is the estimation precision. In this work, we propose a variant of quantum gate verification (QGV) which is robust to practical gate imperfections, and experimentally realize efficient QGV on a two-qubit controlled-not gate and a three-qubit Toffoli gate using only local state preparations and measurements. The experimental results show that, by using only 1600 and 2600 measurements on average, we can verify with 95% confidence level that the implemented controlled-not gate and Toffoli gate have fidelities at least 99% and 97%, respectively. Demonstrating the superior low sample complexity and experimental feasibility of QGV, our work promises a solution to the dimensionality curse in verifying large quantum devices in the quantum era.

References in corpus (10)

• Quantum algorithm for solving linear systems of equations
• Quantum computational advantage using photons
• Efficient quantum state tomography
• Direct Fidelity Estimation from Few Pauli Measurements
• Quantum Tomography via Compressed Sensing: Error Bounds, Sample Complexity, and Efficient Estimators
• Process tomography of ion trap quantum gates
• Self-guided quantum tomography
• Weighted complex projective 2-designs from bases: optimal state determination by orthogonal measurements
• Experimental Estimation of Average Fidelity of a Clifford Gate on a 7-qubit Quantum Processor
• Experimental Monte Carlo Quantum Process Certification

Cited by in corpus (5)

• Statistical Methods for Quantum State Verification and Fidelity Estimation
• Efficient verification of Affleck-Kennedy-Lieb-Tasaki states
• Experimental optimal verification of three-dimensional entanglement on a silicon chip
• Efficient verification of arbitrary entangled states with homogeneous local measurements
• Extending Qubit Coherence Time via Hybrid Dynamical Decoupling