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arXiv · 2005.02378

Single-Copy Certification of Two-Qubit Gates without Entanglement

Yujun Choi·Tanmay Singal·Young-Wook Cho·Sang-Wook Han·Kyunghwan Oh·Sung Moon·Yong-Su Kim·Joonwoo Bae
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Abstract

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.

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Yujun Choi, Tanmay Singal, Young-Wook Cho, Sang-Wook Han, Kyunghwan Oh, Sung Moon, Yong-Su Kim, Joonwoo Bae. 2020-05-05. Single-Copy Certification of Two-Qubit Gates without Entanglement. https://doi.org/10.1103/physrevapplied.18.044046

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