Beginning at time zero

In a recent work, a team of cosmologists from the University of Vienna, led by Florian List, have presented for the first time a novel simulation framework that makes it possible to model the evolution of cosmic structures in a unified setting, and beginning directly at time zero, the Big Bang.

These cosmological simulations are different from everything that has been done in the past, because the sophisticated mathematical models that are needed to describe the early stages of the evolution of the universe are automatically built in. "Cosmological simulations usually consume a lot of time and resources to compute the evolution of cosmic structures during the first hundred million years after the Big Bang, despite the fact that an excellent analytical description is available for how structures form in this epoch.”, says List. “By building this theoretical knowledge into cosmological simulations, we can fast-forward the simulations and directly skip from the Big Bang to a time some hundred million years after, without sacrificing accuracy."

Unraveling cosmic puzzles

This novel approach allows them to unravel cosmic puzzles over the whole lifespan of the Universe and to extend our fundamental understanding of nature. "Cosmological simulations enable the comparison between the predictions arising from our most fundamental theories in physics to the high-quality astronomical observations that are currently being carried out by space missions such as Euclid.

Crucial to make these simulations as fast as possible

For instance, 95% of the energy content of the present-day Universe are thought to be in the form of dark matter and dark energy, and although a vast range of possible explanations exists, the very nature of these two mysterious components is still unknown.”, notes Oliver Hahn, co-author of the study and professor at the Department of Astrophysics as well as Mathematics. “Unfortunately, cosmological simulations are computationally expensive, so in order to test as many well-motivated theories as possible against observations with a limited amount of time and resources, it is crucial to make these simulations as fast as possible. Building analytical knowledge of cosmic structure formation into the simulations allows reducing the number of time steps between the Big Bang and today, resulting in faster simulations."