Beam me up, Scotty! Scientists teleport photons 300 miles into space

Chinese scientists have teleported an object from Earth to a satellite orbiting 300 miles away in space, in a demonstration that has echoes of science fiction.

The feat sets a new record for quantum teleportation, an eerie phenomenon in which the complete properties of one particle are instantaneously transferred to another – in effect teleporting it to a distant location.

Scientists have hailed the advance as a significant step towards the goal of creating an unhackable quantum internet.

“Space-scale teleportation can be realised and is expected to play a key role in the future distributed quantum internet,” the authors, led by Professor Chao-Yang Lu from the University of Science and Technology of China, wrote in the paper.

The work may bring to mind Scotty beaming up the Enterprise crew in Star Trek, but there is no prospect of humans being able to materialise instantaneously at remote locations any time soon. The teleportation effect is limited to quantum-scale objects, such as fundamental particles.

In the experiment, photons were beamed from a ground station in Ngari in Tibet to China’s Micius satellite, which is in orbit 300 miles above Earth.

The research hinged on a bizarre effect known as quantum entanglement, in which pairs of particles are generated simultaneously meaning they inhabit a single, shared quantum state. Counter-intuitively, this twinned existence continues, even when the particles are separated by vast distances: any change in one will still affect the other.

Scientists can exploit this effect to transfer information between the two entangled particles. In quantum teleportation, a third particle is introduced and entangled with one of the original pair, in such a way that its distant partner assumes the exact state of the third particle.

For all intents and purposes, the distant particle takes on the identity of the new particle that its partner has interacted with.

Quantum teleportation could be harnessed to produce a new form of communication network, in which information would be encoded by the quantum states of entangled photons, rather than strings of 0s and 1s. The huge security advantage would be that it would be impossible for an eavesdropper to measure the photons’ states without disturbing them and revealing their presence.

Ian Walmsley, Hooke professor of experimental physics at Oxford University, said the latest work was an impressive step towards this ambition. “This palpably indicates that the field isn’t limited to scientists sitting in their labs thinking about weird things. Quantum phenomena actually have a utility and can really deliver some significant new technologies.”

Scientists have already succeeded in creating partially quantum networks in which secure messages can be sent over optical fibres. However, entanglement is fragile and is gradually lost as photons travel through optical fibres, meaning that scientists have struggled to get teleportation to work across large enough distances to make a global quantum network viable.

The advantage of using a satellite is that the particles of light travel through space for much of their journey. Last month, the Chinese team demonstrated they could send entangled photons from space to Earth. The latest work does the reverse: they sent photons from the mountaintop base to the satellite as it passed directly overhead.

Transmitting into space is more difficult as turbulence in the Earth’s atmosphere can cause the particles to deviate, and when this occurs at the start of their journey they can end up further off course.

The latest paper, published on the Arxiv website, describes how, more than 32 days, the scientists sent millions of photons to the satellite and achieved teleportation in 911 cases.

“This work establishes the first ground-to-satellite up-link for faithful and ultra-long-distance quantum teleportation, an essential step toward global-scale quantum internet,” the team write.

A number of teams, including the European Space Agency and Canadian scientists, have similar quantum-enabled satellites in development, but the latest results suggest China is leading the way in this field.