Gravitational Theory and Cosmology

Gravitational Theory and Cosmology

The Lise Meitner Research Group’s primary focus involves applications of mathematical and numerical relativity to study theories of the origin, evolution, and future of the Universe and the relationship to black hole physics and other aspects of gravitational theory.

Physical cosmology offers some of today's most exciting science opportunities. There is plenty of observational data, and the data points to novel puzzles: What is the dynamical mechanism responsible for the seemingly special initial conditions that seeded all structure, including all planets, stars, and galaxies? What is the origin of the fundamental constituents of matter? What drives the current accelerated expansion phase? And what is the future of our universe?

Our goal is to develop complete theories of the origin, evolution, and future of the universe addressing these issues. We are particularly interested in scenarios that are based on replacing the big bang with a classical (non-singular) bounce from a previous phase of contraction to the current phase of expansion. Apart from providing a powerful explanation for the origin of all structure, bouncing models yield a potential solution to the cosmic singularity problem and hint at the exciting possibility that we could be living in a cyclic universe with bounces occurring every 100 billion years or so.

In addition to model building, we create new tools for solving fully non-linear equations of Einstein general relativity and beyond, for the purpose of testing the viability of the cosmological models and identifying their predictions for forthcoming observations, especially the Simons Observatory and gravitational wave interferometry.

Furthermore, we are interested in investigating the connections to fundamental physics and the implications for gravitational theory in other situations involving space-time singularities, such as black holes.


Faraoni, V.; Giusti, A.; Jose, S.; Giardino, S.: Peculiar thermal states in the first-order thermodynamics of gravity. (2022)

Recent publications

Giardino, S.; Faraoni, V.; Giusti, A.: First-order thermodynamics of scalar-tensor cosmology. Journal of Cosmology and Astroparticle Physics 2022 (04), 053 (2022)
Ijjas, A.; Steinhardt, P. J.: Entropy, Black holes, and the New Cyclic Universe. Physics Letters B 824, 136823 (2022)
Ijjas, A.; Kolevatov, R.: Sourcing curvature modes with entropy perturbations in non-singular bouncing cosmologies. Journal of Cosmology and Astroparticle Physics 2021 (06), 012 (2021)
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