2023-04-27 11:45:23
A peculiar conjecture about quantum information has been confirmed experimentally.
Some things are related, some are not. Suppose we randomly select from the crowd a person who is significantly taller than average. In that case, it is very likely that you also weigh more than average. Statistically, one quantity also contains certain information about the other.
Quantum physics makes it possible to establish even stronger links between different quantities: different particles or parts of a large quantum system can “share” a certain amount of information. In its day, a striking theoretical prediction was made in this regard: the extent of this “mutual information” does not depend on the size of the system, but only on its surface. This surprising result has been confirmed experimentally at the Vienna University of Technology (TU Wien) in Austria.
Theoretical contributions to the experiment and its interpretation are the work of the Max Planck Institute for Quantum Optics in Garching in Germany, the Free University of Berlin in Germany, the Swiss Federal Institute of Technology in Zurich (ETH) and the University of New York in the United States .
The team, made up of Mohammadamin Tajik and Jörg Schmiedmayer, among others, made this pioneering verification using a cloud of ultracold atoms.
The particles were cooled to just slightly above absolute zero. It is called “absolute zero” to the coldest temperature that the laws of physics allow and that is 273.15 degrees Celsius below zero.
The research team made sure that the particles stayed in place.
Vacuum chamber used for the experiment. (Photo: Thomas Schweigler, TU Wien)
At extremely low temperatures, the quantum properties of particles become increasingly important. Information becomes more and more dispersed in the system, and the connection between the individual parts of the global system becomes more and more significant. In this case, the system can be described with a quantum field theory.
To get the information they needed, the researchers perturbed the atoms a bit and observed the resulting dynamics. “It’s like throwing a stone into a pond and obtaining information about the state of the liquid and the pond from the waves generated by the stone,” says Schmiedmayer as an example.
Quantum information today plays an essential role in many technical applications of quantum physics. So the results of the experiment are relevant to various areas of research, from solid state physics to the quantum physics study of gravity, and many others.
The study is titled “Verification of the area law of mutual information in a quantum field simulator”. And it has been published in the academic journal Nature Physics. (Fountain: NCYT de Amazings)
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