Researchers have teleported quantum information over 100 kilometres of optical fibre – four times further than the previous record.
Quantum teleportation involves the remote reconstruction of information encoded in quantum states of matter or light.
As Cathal O’Connell explained in Cosmos magazine last year, teleportation is useful in both quantum communications and quantum computing, with the potential to provide unbreakable encryption and advanced code-breaking.
The new record, described in Optica, involved the transfer of quantum information contained in one photon to another photon transmitted over 102 km of spooled fiber in a National Institute of Standards and Technology (NIST) laboratory in Colorado.
Lead author of the study, Hiroki Takesue, said the record was made possible thanks to new advanced single-photon detectors designed and made at NIST.
“Only about 1% of photons make it all the way through 100 kilometres of fibre,” NIST’s Marty Stevens says. “We never could have done this experiment without these new detectors, which can measure this incredibly weak signal.”
Until now, so much quantum data was lost in fibre that transmission rates and distances were low.
The experiment differ from the one we reported about last year as that one was achieved with electrons – particles of matter – rather than photons – particles of light. As electrons can be trapped at specific locations within their diamond crystals, they can be manipulated and read with relative ease. Particles of light are far harder to work with because they are in constant, very fast motion.