Researchers reveal the purely non-classical character of a three-party quantum network, a prerequisite for creating secure quantum communication systems.
John Stewart Bell suggested in 1964 that correlations between measurements made by the two parties on a pair of entangled particles could prove the non-classical foundations of the quantum world. Researchers have recently performed a series of rigorous tests on Bell's hypotheses that rule out conventional interpretations.
The same has now been done by scientists in China and Spain for a more complex system – a quantum network in which measurements are made by three parties on pairs of entangled particles produced by two sources.
The construction of future secure quantum communication networks is reportedly spurred by researchers' "rigorous" verification of quantum events.
The experiment must be carefully planned to provide a solid test of non-classicality and thus to demonstrate the fallacy of the traditional premises of local realism. If the parties making the measurements can classically communicate with each other during the experiment, or if the two machines that produce the entangled particles can interact with each other, then it is possible that there are classical explanations of supposedly quantum phenomena. These loopholes in the quantum communication system could allow intruders to eavesdrop.
The researchers' experiment bridges these gaps by placing each component of their mesh about 100 meters apart. To ensure that the measurements are truly independent, they also use various quantum random number generators to select the measurement parameters for the three sides. By taking these security measures, the researchers are able to prove that the network meets the nonlocality requirement of the entire network, which confirms that none of the sources of entangled particles can be explained by classical physics.
Source: physics.aps.org/articles/v16/s71
Günceleme: 12/05/2023 14:58