Curved universes in quantum field simulations hot online

Physicists at the University of Heidelberg report that they have developed a quantum field simulator that can be used to simulate curved universes. Such a simulator is important because it will make it possible to measure some cosmic phenomena for the first time, such as particle production due to the expansion of space and the curvature of space-time.

Dimensions and properties of space-time

“Cosmological questions are usually dealt with on unimaginably large scales. Being able to examine them specifically in the laboratory opens up entirely new possibilities for research by experimentally testing new theoretical paradigms,” says Celia Firman, first author of the publication, which was It was published in the November issue of the journal Nature (Quantum field simulator for dynamics in curved space-time).

The quantum field simulator relies on a Bose-Einstein condensate, a state of matter in which an extremely low pressure gas (about 100,000 thinner than an atmosphere) is cooled to a few nanokelvins above absolute zero (273.15 °C). The Heidelberg working group headed by Professor Markus Oberthaler uses a cloud of potassium atoms for this.

In the simulator, which the working group has been developing for several years, the shape of the atomic cloud and thus the dimensions and properties of space-time can now be manipulated. This is useful for research, because so far, for some cosmological questions, only observations and measurements of our own universe can be used, but the space-time structure in them is predetermined. On the other hand, in quantum field simulations, space-time can be manipulated and an entire family of curved universes can be simulated.

Conditions are like in the expanding universe

The atoms are trapped in a thin layer. Excitation can only propagate in two spatial directions – two-dimensional space. The atomic cloud can be formed almost randomly in these two dimensions, so space-times of different curvatures can also be produced. In a flat space like our current universe, the shortest distance between two points is always a straight line. “However, it is conceivable that our universe was curved in its initial stage. Thus investigating the consequences of space-time curvature is an urgent research question,” Oberthaler explains.

Prof. Stefan Flurtchinger, a former scientist at the University of Heidelberg and since the beginning of this year at the University of Jena, explains. He worked on a quantum field theoretical model, with which experimental results were quantitatively compared.

The quantum field simulator was developed as part of the Collaborative Research Center 1225 “Isolated and Global Quantum Systems under Extreme Conditions” (ISOQUANT) at the University of Heidelberg.

(dz)