Quantum Teleportation from a Propagating Photon to a Solid-State Spin Qubit

TL;DR

This paper demonstrates quantum teleportation transferring a photonic qubit to a solid-state spin qubit using entanglement and interference, advancing quantum network technology with semiconductor quantum dots.

Contribution

It presents the first experimental realization of teleporting a photonic qubit to a quantum dot spin qubit with high photon indistinguishability and long coherence times.

Findings

Successful teleportation verified by spin state measurement

High indistinguishability of photons from different quantum dots achieved

Prolonged spin coherence using optical spin-echo sequence

Abstract

The realization of a quantum interface between a propagating photon used for transmission of quantum information, and a stationary qubit used for storage and manipulation, has long been an outstanding goal in quantum information science. A method for implementing such an interface between dissimilar qubits is quantum teleportation, which has attracted considerable interest not only as a versatile quantum-state-transfer method but also as a quantum computational primitive. Here, we experimentally demonstrate transfer of quantum information carried by a photonic qubit to a quantum dot spin qubit using quantum teleportation. In our experiment, a single photon in a superposition state of two colors -- a photonic qubit is generated using selective resonant excitation of a neutral quantum dot. We achieve an unprecedented degree of indistinguishability of single photons from different quantum dots by using local electric and magnetic field control. To teleport a photonic qubit, we generate an entangled spin-photon state in a second quantum dot located 5 meters away from the first and interfere the photons from the two dots in a Hong-Ou-Mandel set-up. A coincidence detection at the output of the interferometer heralds successful teleportation, which we verify by measuring the resulting spin state after its coherence time is prolonged by an optical spin-echo pulse sequence. The demonstration of successful inter-conversion of photonic and semiconductor spin qubits constitute a major step towards the realization of on-chip quantum networks based on semiconductor nano-structures.