Quantum memory for individual polarized photons

Yunfei Wang, Jianfeng Li, Shanchao Zhang +6 more

Dong-Sheng Ding

Dong-Sheng Ding, Wei Zhang, Zhi‐Yuan Zhou +3 more

W. Chang, Chang Li, Yukai Wu +5 more

Realization of long-distance quantum communication through the quantum repeater network requires a combination of some key elements, including a multiplexed quantum memory for storage of entanglement and a telecom photon for propagation of information through the fiber.Although impressive experimental advances have demonstrated the individual elements, combining these key capabilities together and realizing them in a single experimental system remains a significant challenge.Here, we report an experimental realization of long-distance entanglement between a multiplexed quantum memory with 49 individually accessible memory cells and a telecom photon after transmission in a 10-km optical fiber.Excitation of an atomic ensemble generates narrow-band polarization entanglement between a telecom photon of 1530-nm wavelength and another photon of 780-nm wavelength, which is then stored into a memory cell of a multiplexed atomic quantum memory and read out after a controllable delay.The entanglement is verified through quantum-state tomography after quantum storage in the atomic memory and fiber transmission of the telecom photon.This experiment demonstrates an important step towards realization of long-distance quantum communication networks.

Michelle Victora, Jia Jun Wong, Paul G. Kwiat +5 more

Kazuya Tsurumoto, Ryota Kuroiwa, Hiroki Kano +2 more

Abstract Quantum teleportation is a key principle for quantum information technology. It permits the transfer of quantum information into an otherwise inaccessible space, while also permitting the transfer of photon information into a quantum memory without revealing or destroying the stored quantum information. Here, we show reliable quantum state transfer of photon polarization into a carbon isotope nuclear spin coupled to a nitrogen-vacancy center in diamond based on photon-electron Bell state measurement by photon absorption. The carbon spin is first entangled with the electron spin, which is then permitted to absorb a photon into a spin-orbit correlated eigenstate. Detection of the electron after relaxation into the spin ground state allows post-selected transfer of arbitrary photon polarization into the carbon memory. The quantum state transfer scheme allows individual addressing of integrated quantum memories to realize scalable quantum repeaters for long-haul quantum communications, and distributed quantum computers for large-scale quantum computation and metrology.