Recently, Xian-Min Jin’s team from School of Physics and Astronomy, SJTU has realized the quantum-memory-embedded time-energy entanglement at room temperature. The research achievement, entitled "Time-bin entanglement built in room temperature quantum memory", was published online in Physical Review A on June 1, 2021 as Editors' Suggestion.
Prof. Xian-Min Jin’s team has been committed to the research of room-temperature broadband quantum memory for many years. In 2018, the team successfully reduced the noise level to 0.0001 in the quantum region [Communication Physics 1, 55 (2018), npj quantum information 4, 31 (2018)]. Furthermore, the research team proposed a hybrid architecture of broadband storage quantum network and integrated two different types of quantum memories as quantum nodes in the network, which can combine, separate, exchange and split single or multiple photons in the time domain [science advances 6, 6 (2020)].
Recently, based on previous researches, the research team successively injected two groups of write and read pulses into the alkali metal cesium atomic cell. Each group of write and read processes is a quantum storage process, and each group of write and read processes has a certain probability to produce a pair of correlated photons (Stokes and anti-Stokes photons). Once a pair of correlated photons generated, it is impossible to distinguish which group of write and read processes the correlated photons come from, and therefore the time-energy entanglement is constructed. This research realizes the combination of quantum memory and time-energy entanglement at room temperature, which fills the international gap in this field. Combined with the quantum repeater scheme, the research results will be of great significance for the construction of large-scale quantum networks in the future.
The research team thanks the Major projects of Shanghai Science and Technology Commission and key projects of National Natural Science Fund for timely help, and thanks State key research and development plan of Shanghai Science and technology, Shanghai Education Commission for strong support. Tian-Huai Yang, master of integrated quantum information technology research center, School of Physics and Astronomy, SJTU is the first author of the paper, and Prof. Xian-Min Jin is the corresponding author.