Researchers in China have achieved quantum teleportation in free space over a distance of 16 km
Quantum communication promises the world a completely secure way of transferring information, and quantum teleportation is an information transfer protocol that will one day make quantum communication over long distance possible. Previous studies have demonstrated quantum teleportation using an optical fibre, but photon losses due to decoherence in the fibre are large and the transmission distance is limited to 600 metres. Jianwei Pan at the University of Science and Technology of China in Hefei, Chengzhi Peng at Tsinghua University in Beijing and co-workers1 have now achieved quantum teleportation in an optical free-space channel over a distance of 16 kilometres.
The researchers generated an entangled photon pair at Badaling in Beijing using a semiconductor, a blue laser beam and a beta-barium borate crystal. They sent one photon in the pair to 'Alice', situated at Badaling, for measurement. They then sent the other photon in the pair and the results of Alice's measurement to 'Bob' at Huailai in Hebei province 16 kilometres away through the free-space channel.
The researchers used specially designed telescopes to optimize the transmission efficiency and improve the stability of the free-space channel. They found that Bob could recover the results of Alice's measurements using the photon it received, thus demonstrating quantum teleportation. The study confirms the feasibility of quantum teleportation in free space and represents an important step towards quantum communication on a global scale.
Quantum physics:Teleportation goes long distance : Article : Nature China
Quantum communication promises the world a completely secure way of transferring information, and quantum teleportation is an information transfer protocol that will one day make quantum communication over long distance possible. Previous studies have demonstrated quantum teleportation using an optical fibre, but photon losses due to decoherence in the fibre are large and the transmission distance is limited to 600 metres. Jianwei Pan at the University of Science and Technology of China in Hefei, Chengzhi Peng at Tsinghua University in Beijing and co-workers1 have now achieved quantum teleportation in an optical free-space channel over a distance of 16 kilometres.
The researchers generated an entangled photon pair at Badaling in Beijing using a semiconductor, a blue laser beam and a beta-barium borate crystal. They sent one photon in the pair to 'Alice', situated at Badaling, for measurement. They then sent the other photon in the pair and the results of Alice's measurement to 'Bob' at Huailai in Hebei province 16 kilometres away through the free-space channel.
The researchers used specially designed telescopes to optimize the transmission efficiency and improve the stability of the free-space channel. They found that Bob could recover the results of Alice's measurements using the photon it received, thus demonstrating quantum teleportation. The study confirms the feasibility of quantum teleportation in free space and represents an important step towards quantum communication on a global scale.
Quantum physics:Teleportation goes long distance : Article : Nature China