Physicists in China have forged a mysterious quantum connection between particles, called entanglement, over dozens of kilometers of standard optical fiber, setting a new record.
Now, Xiao-Hui Bao, Jian-Wei Pan, and colleagues at the University of Science and Technology of China, Beijing, have demonstrated entanglement over fiber optic links of up to 50 kilometers, as they report this week in Nature.
Still, Hanson says, the experiment is significant because, for a network, the setup link is about half of the basic element called a quantum repeater.
Once physicists had entangled the atom clouds at the ends of each system, they could perform additional measurements on clouds in the middle that would swap the entanglement to the clouds on the ends, stretching the entanglement twice as far.
*Correction, 13 February, 4:30 p.m.: The story has been updated to clarify that the experiment sets a new standard for the longest optical fiber used to entangle two quantum memories and not for the actual distance between the memories.