High-fidelity photonic quantum logic gate based on near-optimal Rydberg single-photon source.

Shi, Shuai; Xu, Biao; Zhang, Kuan; Ye, Gen-Sheng; Xiang, De-Sheng; Liu, Yubao; Wang, Jingzhi; Su, Daiqin et al. · Nat Commun · 2022

basic_science · Level V

Where this comes from

Abstract

Compared to other types of qubits, photon is one of a kind due to its unparalleled advantages in long-distance quantum information exchange. Therefore, photon is a natural candidate for building a large-scale, modular optical quantum computer operating at room temperature. However, low-fidelity two-photon quantum logic gates and their probabilistic nature result in a large resource overhead for fault tolerant quantum computation. While the probabilistic problem can, in principle, be solved by employing multiplexing and error correction, the fidelity of linear-optical quantum logic gate is limited by the imperfections of single photons. Here, we report the demonstration of a linear-optical quantum logic gate with truth table fidelity of 99.84(3)% and entangling gate fidelity of 99.69(4)% post-selected upon the detection of photons. The achieved high gate fidelities are made possible by our near-optimal Rydberg single-photon source. Our work paves the way for scalable photonic quantum applications based on near-optimal single-photon qubits and photon-photon gates.