Beyond the poles in attractor models of inflation
Creators
- 1. Consortium for Fundamental Physics, Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom)
Description
We offer a geometric interpretation of attractor theories with singular kinetic terms as a union of multiple canonical models. We demonstrate that different domains (separated by poles) can drastically differ in their phenomenology. We illustrate this with the help of a "master model" that leads to distinct predictions depending on which side of the pole the field evolves before examining the more realistic example of α-attractor models. Such models lead to quintessential inflation within the poles when featuring an exponential potential. However, beyond the poles, we discover a novel behaviour: the scalar field responsible for the early-time acceleration of the Universe may reach the boundary of the field-space manifold, indicating that the theory is incomplete and 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, however, we discover that quintessence can be achieved without a potential offset. Turning to multifield models with singular kinetic terms, we see that poles generalise straightforwardly to singular curves, which act as "model walls" between distinct pole-free inflationary models. As an example, we study a simple two-field α-attractor-inspired model, whose evolution of isocurvature perturbations is sensitive to where the non-canonical field begins its trajectory. We finally discuss initial conditions in attractor theories, where the existence of multiple disconnected canonical models implies that we must make a fundamental choice: in which domain we impose a distribution for the inflaton in order to then determine the likelihood of inflation.
Availability note (English)
Available from http://dx.doi.org/10.1088/1475-7516/2019/09/022Additional details
Identifiers
Publishing Information
- Journal Title
- Journal of Cosmology and Astroparticle Physics
- Journal Volume
- 2019
- Journal Issue
- 09
- Journal Page Range
- p. 022
- ISSN
- 1475-7516
INIS
- Country of Publication
- United Kingdom
- Country of Input or Organization
- International Atomic Energy Agency (IAEA)
- INIS RN
- 51065049
- Subject category
- S79: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY;
- Descriptors DEI
- ACCELERATION; BOUNDARY CONDITIONS; DISTRIBUTION; FORECASTING; INFLATIONARY UNIVERSE; INFLATONS; NONLUMINOUS MATTER; PERTURBATION THEORY; SCALAR FIELDS; SPACE; UNIVERSE
- Descriptors DEC
- COSMOLOGICAL MODELS; ELEMENTARY PARTICLES; MATHEMATICAL MODELS; MATTER; POSTULATED PARTICLES