To enhance the spatial utility of typical two-port Hadamard gate, we propose a novel single-channel scheme through frequency conversion in Λ-atom-mediated single-photon Raman scattering process in chiral quantum nanophotonics. We demonstrate faithful and efficient gate operations, and quantitatively analyze gate performance. Moreover, by manipulating photon-emitter coupling and frequency detuning, it is confirmed that an arbitrary unitary single-qubit operations are achieved in the presented configuration, including most representative single-qubit Hadamard, X, Z, S, and T gates. Due to the advent of directional emission techniques, the chiral condition is readily experimentally feasible. In addition, we further propose an alternative N-type atom architecture to perform Hadamard operations that are enabled by hyperfine structure in the strong-coupling regime.

Date Published: 4 March 2019
PDF: 12 pages
Proc. SPIE 10933, Advances in Photonics of Quantum Computing, Memory, and Communication XII, 109330Z (4 March 2019); doi: 10.1117/12.2517090

Published in SPIE Proceedings Vol. 10933:
Advances in Photonics of Quantum Computing, Memory, and Communication XII
Philip R. Hemmer; Alan L. Migdall; Zameer Ul Hasan, Editor(s)