Efficiently computing the Uhlmann fidelity for density matrices
Physical Review A American Physical Society 107 (2023) 012427
Abstract:
We consider the problem of efficiently computing the Uhlmann fidelity in the case when explicit density matrix descriptions are available. We derive an alternative formula which is simpler to evaluate numerically, saving a factor of 10 in time for large matrices.Efficiently computing the Uhlmann fidelity for density matrices
ArXiv 2211.02623 (2022)
Cross-verification of independent quantum devices
Physical Review X American Physical Society 11:3 (2021) 031049
Abstract:
Quantum computers are on the brink of surpassing the capabilities of even the most powerful classical computers, which naturally raises the question of how one can trust the results of a quantum computer when they cannot be compared to classical simulation Here, we present a cross-verification technique that exploits the principles of measurement-based quantum computation to link quantum circuits of different input size, depth, and structure. Our technique enables consistency checks of quantum computations between independent devices, as well as within a single device. We showcase our protocol by applying it to five state-of-the-art quantum processors, based on four distinct physical architectures: nuclear magnetic resonance, superconducting circuits, trapped ions, and photonics, with up to six qubits and up to 200 distinct circuits.Cross-verification of independent quantum devices
Institute of Electrical and Electronics Engineers (IEEE) 00 (2021) 1-1