A New Cosmological Model of Dark Matter

The scientists showed that the centers of dark matter halos in this new fuzzy model of dark matter are virtually giant BECs, extending not over millionths of a meter (micrometers) as in typical cold atomic systems, but over thousands of light-years.

Researchers at Newcastle University used insights gained from Bose Einstein’s study of ultracold atomic condensates to analyze the behavior of diffuse dark matter, a new model for cosmological dark matter that recently caught the attention of cosmologists. They found that the physical state of the core of diffuse dark matter halos, the gravitationally bound structures in which galaxies like our own are thought to form, is the same as that of Bose-Einstein condensates (BECs) formed. in laboratory atomic traps. The interdisciplinary team also discovered that the diffuse dark matter surrounding the halo nuclei is in a turbulent state, with vortices and fluctuations that inhibit coherence throughout the halo. These properties distinguish diffuse dark matter from the more widely accepted model of cold dark matter in which there are no coherent features or quantum vortices.

The scientists showed that the centers of dark matter halos in this new fuzzy model of dark matter are virtually giant BECs, extending not over millionths of meters (micrometers) as in typical cold atomic systems, but over thousands of light-years ( equivalent to tens of millions of billions of kilometers), spanning the centers of galaxies and exhibiting a characteristic property of quantum systems and BECs called coherence.

The study also describes the internal motions of the outer halos and the kinetic energy of dark matter there, giving rise to an intricate tangle of quantum vortices with characteristic density profiles at their cores. Their findings have been published in the Monthly Notices of the Royal Astronomical Society.

Cosmology is concerned with the very large scales of nature, from the realms of galaxies and clusters of galaxies to the entire observable universe. Cosmologists make observations of the universe, obviously incapable of experiments, and the main natural force they are concerned with is gravity. Such observations have revealed that most of the matter that makes up the cosmos is different from that that makes up humans, planets, and stars, and is made up of an unknown substance called, for lack of a better word, dark matter. Ultracold atomic physics, on the other hand, describes the behavior of clouds of atoms, such as rubidium, potassium, and sodium gases, typically to millionths of a degree above absolute zero in laboratories around the world, and examines phenomena that reveal the quantum nature of matter.

The study brought these two disciplines together, led by Dr. Gerasimos Rigopoulos and Professor Nick Proukakis of Newcastle University, theorists in cosmology and ultracold atomic physics respectively. The team also included researcher Dr. I-Kang (Gary) Liu, who recently completed his Marie Curie Fellowship on the subject, Dr. Alex Soto, and Ph.D. student Milos Indjin. Dr Rigopoulos, Senior Lecturer in Applied Mathematics, said: “Cosmologists have already studied diffuse dark matter for a few years, but our work has applied concepts from the study of BEC dynamics that have been around for much longer. Now understand that there are specific similarities to BECs and the ultimate goal is to use this knowledge to devise ways to better test this exciting new model observationally.”

“I have always been attentive to interdisciplinary approaches to physics and this has been a perfect problem to approach from that angle. Establishing a common language took some time, but we could see from the very beginning, even when we conceived this project, that there were rewards to be reaped when you step out of your comfort zone and try to see things from a new perspective. I think our perseverance paid off and we’ve only scratched the surface of what a collaboration like this can do.”

Professor Proukakis, a professor of quantum physics and a strong advocate of the universal characteristics of such forms of quantum coherence, added: “It’s great to see another plausible realization of a system showing Bose-Einstein condensation – it’s amazing to see this, as it now they are dealing with a system so large beyond the imagination of the first to study this phenomenon in controlled laboratory settings.” “Although creating a gravitational pull that mimics the potential in controlled laboratory settings remains challenging/unknown in three-dimensional systems, similar initially seemingly impossible challenges have been faced over time in such experimental systems. The mere prospect, though not very likely, of future possibilities of creating laboratory environments that mimic certain aspects of the distribution of matter in the universe is exciting in its own right.” “Also, even as a theoretical playing field, it’s great to have a new system to model, test the extensive experience gained from laboratory condensates, and look forward to future observational tests in cosmology.” Future research will focus on possible ways to observe such diffuse dark matter features, thus placing this model under more detailed observational scrutiny.

source: https://academic.oup.com/mnras/article/521/3/3625/7057880?login=false