researchers explained in "Nature Physics” how one makes collective calculations.
Atoms, consisting of an even number of protons, neutrons and electrons and thus have an “integer spin” come close to absolute zero in a separate state of matter. They form a so-called Bose-Einstein condensate (BEC). In this case, the individual atoms of this atomic cloud completely lose their individuality, and behave as a common quantum object. This is not simply the sum of the individual parts. Such quantum systems can only be simply calculated when they consist of just a few individual parts. Only rough approximations can be used to describe an atomic cloud with thousands of particles.
Kaspar Sakmann of the Institute of Atomic and Subatomic Physics at the Vienna University of Technology and his colleague Mark Kasevich of Stanford University, USA showed that such effects can also be calculated in BEC, such as quantum waves. “First we calculate the probability of the first particle being measured on a certain position. The probability distribution of the second particle depends on where the first particle has been found, the position of the third particle depends on the first two and so on,” Sakmann explained. In order to be able to describe the position of the very last particle, all the other positions have to be known.
As a result, not only quantum waves in colliding BEC can be calculated, but also certain vortices in the condensates which are stirred with a laser beam. Thus the correlations among the particles can be correctly determined, and also in other quantum systems if certain modifications are carried out, according to the scientists.