Nuclear spins of noble-gas atoms are exceptionally isolated from the environment and can maintain their quantum properties for hours at room temperature. Here we develop a mechanism for entangling two such distant macroscopic ensembles by using coherent light input. The interaction between the light and the noble-gas spins in each ensemble is mediated by spin-exchange collisions with alkali-metal spins, which are only virtually excited. The relevant conditions for experimental realizations with ${}^3\mathrm{He}$ or ${}^{129}\mathrm{Xe}$ are outlined.

• Received 24 June 2019

DOI:https://doi.org/10.1103/PhysRevLett.124.043602