Quantum Optics Seminar by Barak Dayan, Professor, Weizmann Quantum Optics, Israel

Deterministic quantum gates between single photons and single quantum emitters are a valuable building block for the distribution of quantum information between remote systems, as well as for the construction of valuable photonic states. I will review the tools cavity-QED provides for the construction of such gates, and present our recent demonstration of a photon-atom swap gate [1]. The underlying mechanism is single-photon Raman interaction (SPRINT) - an interference-based effect in which a photonic qubit deterministically controls the state of a material qubit and vice versa [2-4]. This open-system scheme is applicable to any waveguide-coupled Lambda system; it has been also demonstrated in microwave with superconducting qubits [5-6], and is also relevant for Quantum Dots coupled to photonic waveguides [7-8]. The scheme provides a basis for a variety of photon-"atom" interactions - from universal gates, through QND measurement, to the preparations of nonclassical states of light such as single-photon subtracted or added states, CAT states, and cluster states for one-way photonic quantum computation.

[1] Nature Physics 14, 996 (2018)

[2] Science 345, 903 (2014)

[3] Nature Photonics 10, 19 (2016)

[4] Phys. Rev. A 95, 0333814 (2017)

[5] Phys. Rev. Lett. 113, 0636104 (2014)

[6] Nature Communications 7, 1 (2016)

[7] Rev. Mod. Phys. 87, 347 (2017)

[8] arXiv:1903.12332 [quant-ph] (2019)