28 November 2019
King's College London
Europe/London timezone

Questions and enquiries can be directed to Dries Seynaeve.

Field-space geometry of cosmological attractors

28 Nov 2019, 11:45
30m
Seminar Room 3, Prideaux Building, St Thomas' Campus (King's College London)

Seminar Room 3, Prideaux Building, St Thomas' Campus

King's College London

163 Lambeth Palace Rd, South Bank, London SE1 7JU
Talk Session 1

Speaker

Dr Sotirios Karamitsos (University of Manchester)

Description

In this talk, I will discuss the geometry of attractor theories in a cosmological context, showing that theories which feature poles act as unions of multiple canonical models. This means that poles demarcate different field-space domains which may drastically differ in their phenomenology. Usually, studies of attractor theories are confined within the poles; however, moving beyond the poles can be an invaluable tool in identifying novel robust and well-motivated models. As a concrete example, the scalar field responsible for the early-time acceleration of the Universe may reach the boundary of the field-space manifold when outside the poles, indicating that a boundary condition must be imposed in order to determine its late-time behaviour. If the evolution of the field is arrested before this happens, we find that quintessence can be achieved without a potential offset, which is an example of a new model with desirable features. Turning to multifield models with singular kinetic terms, I show that poles generalise straightforwardly to singular curves, acting as "model walls" between distinct pole-free inflationary models. I demonstrate that in this case, the evolution of isocurvature perturbations can be sensitive to where the non-canonical field begins its trajectory. This has far-reaching implications for the initial conditions of attractor theories, since it implies that we must make a fundamental choice as to which domain we impose initial conditions on the fields.

Author

Dr Sotirios Karamitsos (University of Manchester)

Presentation materials