Volume and gauge symmetry

Abstract: Theories with a preferred volume are called unimodular. Unimodularity has played subtle roles in theories of gravity since the inception of General Relativity [1]; it is well-known that unimodularity provides an alternative view to the important problems with the cosmological constant Λ. This seminar aims to clarify* unimodular physics from the perspective of relativity and gauge symmetries, and to present two relevant current developments. 1) Despite various teleparallel modifications of gravity considered in the literature, the only known viable class of modifications can be understood in terms of a preferred volume [2]. In contrast to modifications of gravity, local Lorentz symmetry is not speculative. 2) The incorporation of this symmetry into a unimodular theory predicts the standard ΛCDM model of cosmology without postulating dark energy or dark matter [3]. It also facilitates the coupling of the Standard Model gauge and Higgs fields into the theory [4].

[1] Einstein, A. (1916) The Foundation of the General Theory of Relativity. Annalen der Physik, 49, 769-822. [2] Bello-Morales et al (2024) A class of ghost-free theories in symmetric teleparallel geometry, e-Print: 2406.19355. [3] Gallagher, P. and Koivisto, T. (2021) The Λ and the CDM as Integration Constants, Symmetry 13 11, 2076. [4] Wilczek, F. (1998) Riemann-Einstein structure from volume and gauge symmetry Phys.Rev.Lett. 80 4851-4854.

*In generally understandable terms, avoiding exterior algebra and such modern notations.

astrophysicscondensed mattergeneral relativity and quantum cosmologyhigh energy physicsmathematical physicsclassical physicsgeneral physics

Audience: researchers in the topic

Theoretical physics seminar @ Tartu