Consortium for Fundamental Physics - Particle Cosmology and Fundamental Physics: From the Early to the Present Universe
Lead Research Organisation:
University of Sheffield
Department Name: Mathematics and Statistics
Abstract
Particle cosmology is about understanding the Universe. It addresses many questions such as: How did the Universe begin? What are its constituents within it? Was there a Big Bang or was the Universe always there? What is dark matter and what is dark energy, that causes the expansion of the Universe to accelerate? Over the years, cosmologists and particle physicists have developed a standard model which describes the observed properties of the Universe very well. The model is called the LambdaCDM model. It relies on some form of dark matter which interacts with ordinary matter only via gravity. The accelerated expansion is explained by a constant dark energy density (the cosmological constant Lambda). According to this model, the history of our Universe began with a singularity and a subsequent era of accelerating expansion, called inflation. It remains one of the goals of particle cosmology to understand inflation better. While the LambdaCDM model raises many questions, it provides a good starting point to explain the observed properties of the Universe.
Recently, however, some cracks have appeared in our understanding. For example, different methods to measure the current expansion rate of the Universe disagree by a wide margin. Additionally, the clustering of dark matter is also not fully understood. These cracks show that some of the assumptions on which the LambdaCDM model rests may be in need of refinement. Members of our Consortium will study models of the very early Universe, by developing models which relate inflation to the physics of dark energy. They will further study more refined models of dark matter, by studying interacting particles and their impact on the formation of structures. Our scientists are working on particle physics explanations of the accelerated expansion and the possible interplay between dark matter and dark energy. There is a plethora of new cosmological and astrophysical data coming in during the next decade which allow scientists to probe the properties of dark matter and dark energy with ever-growing accuracy. We will develop new theories for the dark sector, which are in full agreement with current data but can be probed further with new data coming in.
The Big Bang singularity, one of the predictions of the LambdaCDM model, signals a breakdown of the laws of physics. Physicists believe that a more complete theory, which combines the physics of the very small (quantum mechanics) with gravity, will tell us how the current universe came into existence. Our researchers develop models of the very early universe and find ways to test these with future observations.
Theories of particle physics can not not only be tested by cosmological considerations. General Relativity, Einstein's theory of Gravity, predicts the existence of black holes, regions of space from which nothing can escape, not even light. Our scientists are studying the conditions under which BHs are stable and how they affect the interactions of particles around them, including hypothetical extremely light particles called axions, which could be the dark matter in the universe.
Recently, however, some cracks have appeared in our understanding. For example, different methods to measure the current expansion rate of the Universe disagree by a wide margin. Additionally, the clustering of dark matter is also not fully understood. These cracks show that some of the assumptions on which the LambdaCDM model rests may be in need of refinement. Members of our Consortium will study models of the very early Universe, by developing models which relate inflation to the physics of dark energy. They will further study more refined models of dark matter, by studying interacting particles and their impact on the formation of structures. Our scientists are working on particle physics explanations of the accelerated expansion and the possible interplay between dark matter and dark energy. There is a plethora of new cosmological and astrophysical data coming in during the next decade which allow scientists to probe the properties of dark matter and dark energy with ever-growing accuracy. We will develop new theories for the dark sector, which are in full agreement with current data but can be probed further with new data coming in.
The Big Bang singularity, one of the predictions of the LambdaCDM model, signals a breakdown of the laws of physics. Physicists believe that a more complete theory, which combines the physics of the very small (quantum mechanics) with gravity, will tell us how the current universe came into existence. Our researchers develop models of the very early universe and find ways to test these with future observations.
Theories of particle physics can not not only be tested by cosmological considerations. General Relativity, Einstein's theory of Gravity, predicts the existence of black holes, regions of space from which nothing can escape, not even light. Our scientists are studying the conditions under which BHs are stable and how they affect the interactions of particles around them, including hypothetical extremely light particles called axions, which could be the dark matter in the universe.