Lomonosov Moscow State University

Shtennikova Arina

  • PhD Student

My scientific interests lie in the field of studying modified theories of gravitation, namely the Horndeski theory and its extensions. Horndeski theory is the most general scalar-tensor theory of gravitation in four-dimensional spacetime. Despite the presence of higher derivatives in the action it avoids the occurrence of gradient divergences. The study of these theories gives an opportunity to construct non-singular cosmological solutions, which are forbidden in the General Theory of Relativity. However, due to the large arbitrariness in the choice of Lagrangian functions, an additional study of the stability of the solutions of the theory is required. A significant limitation is the no-go theorem, according to which, in the absence of strong coupling, gradient instabilities, and ghosts degrees of freedom in the theory, it is impossible to construct a stable solution to general Horndeski theory on the entire time axis. Weakening at least one of the conditions of the theorem provides opportunities to construct stable solutions, the study of one of these opportunities is the focus of one of my papers.
Then I switched to the study of the behavior of perturbations on an anisotropic cosmological background of Bianchi type I. The study of cosmology on such a background can be interesting within the framework of the conversation about anisotropy at early stages of the Universe development, or about small anisotropy of the relic radiation, which is not completely homogeneous and isotropic after all.
Also interesting is the possibility of adding not only scalar but also vector fields to the theory, which is a further goal of my research.

Selected Publications:

Mironov, S., & Shtennikova, A. (2023). Stable cosmological solutions in Horndeski theory. Journal of Cosmology and Astroparticle Physics, 2023(06), 037.

Publications affiliated with ITMP:

  1. Mironov, S.Shtennikova, A.Valencia-Villegas, M. (2024). "Reviving Horndeski after GW170817 by Kaluza-Klein compactifications". arXiv: 2405.02281 [hep-th].

All publications