It could herald the start of a new era of ultrasecure communications that can never be hacked.
China has held the world's first quantum intercontinental video conference between laboratories in Beijing and Vienna.
The call was held using a new world first space-ground quantum communication network that experts say could revolutionise how humans connect.
Quantum messaging represents the safest possible form of communication we can achieve because it is unhackable.
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China has held the world's first quantum intercontinental video conference between laboratories in Beijing and Vienna. The call was held using a new space-ground quantum communication network - also a world first - that could revolutionise how humans connect
In quantum physics, entangled particles remain connected so that actions performed by one affects the behaviour of the other, even if they are separated by huge distances.
This means if you measure, 'up' for the spin of one photon from an entangled pair, the spin of the other, measured an instant later, will be 'down' - even if the two are on opposite sides of the world.
Entanglement takes place when a part of particles interact physically. For instance, a laser beam fired through a certain type of crystal can cause individual light particles to be split into pairs of entangled photons.
The theory that so riled Einstein is also referred to as 'spooky action at a distance'. Einstein wasn't happy with theory, because it suggested that information could travel faster than light.
Traditional public key cryptography, used in most modern internet communications including emails, usually relies on the perceived computational intractability of certain mathematical functions.
In contrast, quantum key distribution (QKD) uses single photons in quantum superposition states to guarantee unconditional security between distant parties.
The call was held between President Chunli Bai of Beijing's Chinese Academy of Sciences and President Anton Zeilinger of Vienna's Austria Academy of Sciences.
The Chinese science academy said the encrypted communication system was being trialled for potential 'real-world applications by government, banks, securities and insurance companies'.
There are plans to carry out similar test conversations between someone in China and four other places, Singapore, Italy, Germany and Russia.
Technical reasons had previously limited such conversations to distances of a few hundred kilometres, the academy said, but they had found a 'promising solution to this problem' involving a 'sophisticated satellite, named Micius'.
It is equipped with 'a decoy-state QKD transmitter, an entangled-photon source, and a quantum teleportation receiver and analyser'.
As the satellite moves through its orbit, its distance from the Tibetan ground station varies from 500 km to 1400 km (310.7 – 869.9 miles). In the up-link approach, the transmitter is located at the ground station, while the satellite acts as the receiver, as illustrated
Five ground stations have also been built in China and Tibet.
Earlier this year scientists in China successfully transmitted entangled photons farther than ever before, achieving a distance of up to 1,400 kilometers (870 miles) between suborbital space and Earth.
Using the same 'quantum satellite' Micius, the scientists were able to to transmit a photon from an entangled pair from the ground station in Tibet to the orbiting craft, in what's known as an uplink configuration.
The 1,300 pound craft satellite is equipped with a laser beam, which the scientists subjected to a beam splitter.
This gave the beam two distinct polarized states.
In the uplink approach, the transmitter is located at the ground station, while the satellite acts as the receiver.
Not only did the team successfully transmit single-photon qubits over hundreds of miles for the first time, but they managed to do it for six input states, to 'demonstrate that the quantum teleportation is universal.'