Accurate simulations provide perspective on the structure of the universe

The universe is full of galaxies, which on large scales exhibit a filamentary pattern, referred to as the cosmic web. This heterogeneous distribution of cosmic material is in some ways like blueberries in a cake where material collects in certain areas but may be missing in others.

Based on a series of simulations, the researchers began to probe the heterogeneous structure of the universe by treating the distribution of galaxies as collections of points — like individual particles of matter that make up matter — rather than as a continuous distribution. This technique enabled the application of mathematics developed for Materials science to estimate the relative disorder of the universe, allowing a better understanding of its basic structure.

“What we found is that the distribution of galaxies in the universe is very different from the physical properties of conventional materials, which have their own unique signature,” explained Oliver Vilkox, a co-author of the study.

This work is now published in X physical reviewSalvatore Torquato, Institute for Advanced Study permanent member and Louis Bernard Professor of Natural Sciences in the Departments of Chemistry and Physics at Princeton University; and Oliver Vilcox Visiting Ph.D. Student of the Institute from September 2020 to August 2022 and is now a Junior Fellow of the Simmons Society of Fellows, hosted by Columbia University.

The pair analyzed public simulation data generated by Princeton University and the Flatiron Institute. Each of the 1,000 simulations consists of a billion “particles” of dark matter, the clusters of which were formed by gravitational evolution, and act as surrogates for galaxies.

One of the main findings of the paper concerns correlations between pairs of galaxies that are topologically related to each other via the pairwise correlation function. Based on this – and the host of other descriptors that have emerged in heterogeneous media theory – the research team has shown that on larger scales (on the order of several hundred megaparsecs), the universe approaches hyper-uniformity, while on smaller scales (up to 10 megaparsecs) it becomes nearly anti-uniform. Severely hyperemic and heterogeneous.

Torquato stated that the “observable shift between order and chaos depends largely on scale”. Georges Seurat’s pointillist style in the painting A Sunday on La Grande Jatte produces a similar visual effect; the work appears disordered when viewed up close and highly ordered from afar. In terms of entropy, the degree of order and disorder is more subtle, as is the case with the Rorschach inkblot test. which can be interpreted in an infinite number of ways.”

Statistical tools, namely the nearest-neighbours distributions, cluster diagnostics, Poisson distributions, nomination thresholds, and the pairwise correlation function, have allowed the researchers to develop a consistent and objective framework for measuring rank. Therefore, their findings, while performed in a cosmological context, translate to a number of other dynamical and physical systems.

this Multidisciplinary workThe combination of the techniques of cosmology and condensed matter physics has future implications for both fields. beyond distribution galaxiesMany other features of the universe can be explored with these tools, including cosmic voids and bubbles of ionized hydrogen formed during the reionization phase of the universe.

On the contrary, new phenomena discovered about being It may also provide insight into various material systems on Earth. The team recognizes that more work is needed before these techniques can be applied to real data, but this work provides a solid proof-of-concept with great potential.