Improved entanglement detection with subspace witnesses
Won Kyu Calvin Sun, Alexandre Cooper, Paola Cappellaro · Physical Review A · 2020
A ``subspace'' witness of entanglement, more robust than a typical state fidelity-based witness, is introduced and experimentally tested with a hybrid two-qubit system composed of electronic spins in diamond. Its straightforward implementation offers improved detection of specific genuine multipartite entangled states in noisy, intermediate-scale quantum processors.