A quantum state transformation can be generally approximated by single- and two-qubit gates. This, however, does not hold with noisy intermediate-scale quantum technologies due to the errors appearing in the gate operations, where errors of two-qubit gates such as controlled-NOT and SWAP operations are dominated. In this work, we present a cost efficient single-copy certification for a realization of a two-qubit gate in the presence of depolarization noise, where it is aimed to identify if the realization is noise-free, or not. It is shown that entangled resources such as entangled states and a joint measurement are not necessary for the purpose, i.e., a noise-free two-qubit gate is not needed to certify an implementation of a two-qubit gate. A proof-of-principle demonstration is presented with photonic qubits.
@article{arxiv.2005.02378,
title = {Single-Copy Certification of Two-Qubit Gates without Entanglement},
author = {Yujun Choi and Tanmay Singal and Young-Wook Cho and Sang-Wook Han and Kyunghwan Oh and Sung Moon and Yong-Su Kim and Joonwoo Bae},
journal= {arXiv preprint arXiv:2005.02378},
year = {2022}
}
Comments
9 pages. arXiv admin note: text overlap with arXiv:1812.02087