Teleportation may be a concept usually reserved for science fiction, but researchers have shown that it can be used to prevent the loss of communication channels at the quantum level.
The team, including researchers from the Center for Quantum Dynamics at Griffith University, highlighted issues with the inherent loss that occurs in every form of communication channel (e.g. internet or telephone) and discovered a mechanism that can reduce this loss.
Professor Geoff Pryde, Dr Sergei Slussarenko, Dr Sacha Kocsis and Dr Morgan Weston, along with researchers from the University of Queensland and the National Institute of Standards and Technology, say the discovery is a milestone important towards the implementation of the “quantum internet”, which will bring unprecedented capabilities that are not accessible with today’s web.
Dr Slussarenko said the study was the first to demonstrate an error reduction method that improved channel performance.
“First, we looked at the raw data transmitted through our channel and could see a better signal with our method than without,” he said.
“In our experiment, we first sent a photon through the loss – that photon doesn’t carry any useful information, so losing it wasn’t a big deal.
“We could then correct for loss effects via a device called a noiseless linear amplifier developed at Griffith and the University of Queensland.
“He can recover the lost quantum state, but he can’t always succeed; sometimes it fails.
“However, once the recovery is successful, we then use another purely quantum protocol – called quantum state teleportation – to teleport the information we wanted to transmit into the now-corrected carrier, thus avoiding any loss on the channel.”
Quantum technologies promise revolutionary changes in our information-based society, and quantum communication is developing methods such as the one demonstrated in this study to transmit data in extremely secure and secure ways, so that it is impossible to access it by a third party.
“Short distance quantum encryption is already in commercial use, but if we want to implement a global quantum network, photon loss becomes a problem because it is unavoidable,” Dr. Slussarenko said.
“Our work implements a so-called quantum relay, a key ingredient in this long-distance communication network.
“The no-cloning theorem forbids making copies of unknown quantum data, so if a photon that carries information is lost, the information it was carrying is lost forever.
“A functioning long-distance quantum communication channel needs a mechanism to reduce this loss of information, which is exactly what we did in our experiment.”
Dr Slussarenko said the next step in this study would be to reduce errors to a level where the team could implement long-distance quantum cryptography and test the method using real optical infrastructure, such as those used for the fiber-based internet. .
The results were published in the journal Nature Communication.
Reference: “Quantum channel correction outperforming direct transmission” by Sergei Slussarenko, Morgan M. Weston, Lynden K. Shalm, Varun B. Verma, Sae-Woo Nam, Sacha Kocsis, Timothy C. Ralph and Geoff J. Pryde, April 5, 2022 , Nature Communication.