While the world is trying to solve the puzzle of quantum physics, China's scientists have taken it to a whole new level and brought quantum experiments to space. The country has become a pioneer in launching the first ever quantum communications satellite, that will allow learning about quantum physics and if successful, would be able to mitigate cyber attacks.
The experiment is officially known as Quantum Experiments at Space Scale (QUESS), but also known as Mozi, after the Chinese philosopher who is believed to be the first to conduct optical experiments. The QUESS satellite will deploy a quantum cryptography using a prototype to test whether it's possible to apply quantum physics in space. QUESS's mission will last two years and if all goes to plan, it will be possible to transmit 'unhackable' keys from space to the ground through quantum entanglement.
The basics of quantum include processing data with 'qubits' (quantum particles), instead of common bits and the binary system. This allows photons (particles of qubit) to exist in multiple states at the same time, so instead of being stored as either 0 or 1, it can be 0 and 1. According to Live Science, quantum entanglement occurs when a pair of photons interact physically but at a large distance. A laser beam is fired through a special crystal which splits individual photons into entangled ones, but once split at a large distance, they still remain connected, and can create a secure communication channel. The principle of quantum entanglement was discussed by scientists, including Albert Einstein who referred to it as a 'spooky action at a distance'.
If used correctly, quantum entanglement would open the door to the lock-and-key security system and that China is trying to achieve with QUESS. The satellite has a built-in crystal that can be stimulated to produce entangled photons at a quantum level. The experiment is going to be performed at 1,200 km and is in space because scientists believe that it's easier to deal with delicate photons there, rather than on the ground, due to particles being easily interrupted with when travelling through air or fibres. If QUESS's experiment is successful, when measured, one photon will show its observers a random polarization state, with another photon always showing the same random state. Correlated polarizations will be the basis of a cryptographic key - known and seen only to its observers.
Usually, hackers perform cyber attacks by intervening within the system through transmitted signals. QUESS can be a game changer because quantum entanglement doesn't require transmission and uses other principles, therefore, there would be no known interception possible, because that very distant, but at the same time very close connection between photons, ensures there can't be a 'third wheel' that may access the information or listen-in. If, however, there is an intervention, then observers would immediately notice it, as photons would cease to be perfectly correlated.
China is not the only country to perform such experiments but is the first to go that far. According to Chinese state media station, Xinhua, 'users will be able to send messages securely and at speeds faster than light.' There are still two years of the mission ahead, but this quantum leap no longer sounds ridiculous.