BEIJING — China is leading the pack in terms of quantum space experiments after the country announced that setting a new distance record for beaming entangled particles from space to Earth.
The experiment was conducted from the Quantum Experiments at Space Scale (QUESS) satellite, nicknamed Micius, in reference to a fifth century B.C. Chinese philosopher. It is believed photons travel more smoothly in the near-vacuum of space.
Quantum communication relies on a phenomenon known as quantum entanglement, in which particles influence each other, even when separated by great distances.
A photon can be split into pairs of entangled photons by a laser beam. The entangled photons influence one another, so that if one photon changes its state, the other reacts instantly by taking up a state relative to the photon. The photons remain entangled even when one is far away.
Quantum communication could greatly enhance security, as any interception of the information will necessarily alter the state of the photons, thus giving away the eavesdropper.
According to Science, the team produced entangled photons by sending a laser beam through a light-altering crystal onboard the satellite. The photons were sent to two receiving stations in Delingha and Lijiang, 1,200 km apart. Opposite polarization states were measured at the two stations, confirming the entanglement — otherwise known as “spooky action” — was achieved over a record distance.
