Pinpoint simulations provide perspective on universe structure

The cosmic web is a filamentary pattern of galaxies that can be seen on vast scales throughout the cosmos. Similar to blackberries in a muffin, the material in the universe is distributed unevenly, clustering in some places but possibly missing in others.

Based on a series of models, scientists have started to investigate the heterogeneous structure of the universe by considering the distribution of galaxies as a collection of points rather than as a continuous distribution, similar to the individual bits of matter that make up a substance. This method has made it possible to measure the relative disorder of the universe and use mathematics created for materials science to better comprehend the universe's basic structure.

Oliver Philcox, a co-author of the research, said, "What we discovered is that the distribution of galaxies in the cosmos is quite distinct from the physical characteristics of conventional materials, having its own unique signature.

Salvatore Torquato, a frequent member and visitor at the Institute for Advanced Study and Lewis Bernard Professor of Natural Sciences based in the departments of chemistry and physics at Princeton University, and Oliver Philcox, a visiting Ph.D. student at the Institute from September 2020 to August 2022 and currently a Junior Fellow in the Simons Society of Fellows, hosted at Columbia University, collaborated on this work, which has just been published in Physical Review X.

The two researchers examined open modeling data produced by the Flatiron Institute and Princeton University. One billion dark matter "particles" make up each of the 1,000 simulations, and the groups they create through gravitational development act as stand-ins for galaxies.

The connections between pairs of galaxies that are topologically linked to one another using the pair-connectedness function are one of the paper's key findings. The research team demonstrated that, on larger scales (on the order of several hundred megaparsecs), the universe approaches hyperuniformity, whereas on smaller scales (up to 10 megaparsecs), it becomes almost antihyperuniform and strongly inhomogeneous. Based on this and the variety of other descriptors that emerge in the theory of heterogeneous media.

Scale is a major factor in how order and chaos are viewed, according to Torquato. "Similar visual effects are produced by Georges Seurat's pointillist method in the picture A Sunday on La Grande Jatte; the piece looks highly ordered up close and disorganized from a distance. The degree of order and chaos in the world is more subtle, comparable to the infinitely interpretable Rorschach inkblot test."

The researchers were able to create a consistent and impartial paradigm for assessing order thanks to statistical tools, particularly nearest-neighbor distributions, clustering diagnostics, Poisson distributions, percolation thresholds, and the pair-connectedness function. Their conclusions therefore apply to a variety of other dynamical physical systems even though they were formulated in a cosmic setting.

Future developments in both astronomy and condensed matter physics are likely as a result of this multidisciplinary research. Many other aspects of the universe, such as cosmic voids and the ionized hydrogen bubbles that developed during the universe's reionization period, can be studied with these instruments in addition to the spread of galaxies.

On the other hand, new cosmological phenomena may also shed light on different Earthly material systems. Although the team is aware that more research will need to be done before these techniques can be used with actual data, this work offers a powerful proof-of-concept with enormous promise.