Polarization-to-spin conversion and entanglement distribution via coherent interface with semiconductor double quantum dot

Chien-Yuan Chang^1*, K. Kuroyama¹, S. Matsuo¹, S. R. Valentin³, A. Ludwig³, A. D. Wieck³, Seigo TARUCHA^1,2

¹Applied Physics, The University of Tokyo, Tokyo, Japan
²Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität, Bochum, Germany
³The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
⁴Center for Emergent Matter Science (CEMS), RIKEN, Tokyo, Japan

* Presenter:Chien-Yuan Chang, email:cychang@meso.t.u-tokyo.ac.jp

Interfacing photonic qubits with spin qubits remains critical challenges in semiconductor devices. In this talk, we will demonstrate the critical properties of the coherent interface with a gate-defined double quantum dot device by two separate experiments, quantum state transfer, and entanglement absorption. We report the quantum state transfer implemented on the single shot readout of a single spin generated in a GaAs quantum dot by spin-selective excitation with linearly polarized photon. The optical spin blockade effect requires in-plane magnetic field and frequency-selected photon associate to Zeeman-splitted light-holes, but not heavy-holes. This effect, following the optical selection rules, determines the generation efficiency depending on the photon polarization and the electron number in the dot. Secondly, we observe the entanglement absorption between an entangled photon pair to a single spin and a photon. Specifically, (one of) the polarization-entangled photon spin-selectively excites a Zeeman-splitted light-hole/electron pair, results in distinguishable trapping events. We confirm individual entanglement transferal events by the temporal coincidences and the conditional probabilities of the polarized photon and the spin correlation. In conclusion, we validate the fulfillment of quantum networking technology with an integrable and highly-compatible quantum system.

Keywords: Quantum state transfer, Photonic to spin qubit