They want to store the state of received photons on „quantum harddrives“, transport them to the same place, read the states out and let them interfere locally.
This is the mentioned paper from december 2020 about hour-long optical storage (by Chaun-Feng Li et al.):
This is the mentioned paper from december 2020 about hour-long optical storage (by Chaun-Feng Li et al.):
https://arxiv.org/abs/2012.14605
(Earlier article from 2015 about this storage technique: https://newatlas.com/quantum-encryption-storage-drive/35553/ )