A fundamental cell in fast quantum Internet could be the controlled teleportation of quantum bits, which has been proven experimentally for the first time anywhere in the world by experts from the Joint Laboratory of Optics of Palacký University Olomouc and the Institute of Physics of the Czech Academy of Sciences. Thanks to the controlled transmission of a quantum state, the flow of information in communications networks could be significantly increased, even over large distances. The results of the research of the Olomouc team of experts have been published the journal Physical Review Letters.
Scientists at the Joint Laboratory explored the controlled transmission of a quantum state, and finally confirmed it under laboratory conditions. “Our experiment opens the possibility of quantum communication networks working on the principle of changes in quantum states. Thanks to this, we could make use of all the advantages which quantum physics offers us in the communication networks of the future,” said Karel Lemr.
The basis of the unique experiment was the controlled teleportation of quantum bits (“qubits”) as the information carriers. Prior to this, quantum teleportation had only been carried out between two users. One of them sends quantum information to the other and the second receives it, during which the content is unable to be influenced. Olomouc scientists chose teleportation in a group of three users out of whom a random one decides whether the teleportation of the quantum state – and thus the information between the two remaining users – would or would not be carried out. The random user has the role of the controller in the group.
“Thus a kind of elemental triangle of users was created, between whom there was controlled quantum teleportation, whose random apex could be replaced by the apex of another similar triangle. It could be imagined as the basic cell of a new type of communication network. If this method were to be extended further, an entire system based on the teleportation of a quantum state could be gradually chained into the form of something which in the future could be called quantum Internet,” Lemr explained.
The work of the Olomouc scientists could also significantly contribute to the development and practical use of quantum cryptography, metrology, and the construction of quantum computers. “The quality of encryption in quantum cryptography is guaranteed by natural physical laws. It is not established solely on trusting that an attacker would not have enough computational ability to break the encryption. Quantum metrology is also much more precise than standard measuring methods, and a quantum computer would speed up several computational operations,” remarked the scientist.
In the public’s mind, quantum teleportation still has an air of mystery and is surrounded by various myths. “Quantum teleportation certainly is not a means of transporting objects through the universe like on Star Trek. It is no supernatural magic skill. It is the transference of the essence of a certain object which in physics we call a quantum state, from one place to another, without it being necessary to transfer the object itself,” added Lemr.
The theoretical idea of teleportation of a quantum state came from their Polish colleague, Artur Barasiński. “We adjusted it in order to make it experimentally possible. The construction of the experiment itself did not take so long, because it was based on our previous multiphoton experiments,” said Antonín Černoch of the Joint Laboratory of Optics. The project was supported by two grants from the Czech Science Foundation and one grant from the Excellence in Research Operational Programme in Research, Development and Education.