Condensed Matter Seminar: Quantum logic gates between single photons and single atoms

Abstract:

Deterministic quantum gates between single photons and single quantum emitters are a valuable building block in the field of quantum computing and quantum communication. Specifically, they enable the distribution of quantum information between remote systems, as well as for the construction of valuable quantum photonic states that are the basis for photonic quantum computers. 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 ions [7] and Quantum Dots coupled to photonic waveguides [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] arXiv:1902.03469v2 [quant-ph] (2019)

[8] Rev. Mod. Phys. 87, 347 (2017)

Event Organizer: Prof. Eran Sela