Physics and Astronomy - Cosmology Seminar - Jerome Quintin, McGill University

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Physics and Astronomy - Cosmology Seminar - Jerome Quintin, McGill University

Title: "Cuscuton Gravity as a Stable Limiting Curvature Theory"

Wednesday, April 3, 2019
2:00pm-3:00pm
Wilder 202
Intended Audience(s): Public
Categories: Lectures & Seminars
Abstract: The idea behind the limiting curvature hypothesis is that there should
exist a fundamental length scale, probably of the order of the Planck
length, that sets a bound on all curvature invariants. Constructing a
theory that satisfies the limiting curvature hypothesis would therefore
be free of singularities, e.g. including the Big Bang initial
singularity and the singularity at the center of black holes. Building
such theories is not a trivial task, and existing models either fail at
avoiding all divergences at the background level or have instabilities
at the perturbative level. In this talk, I will review an apparently
unrelated modified theory of gravity, the cuscuton, which proposes to
add an incompressible scalar field with a non-canonical kinetic term to
standard general relativity. I will review the properties of the
cuscuton and show how it represents a limiting curvature theory in a
cosmological setup, hence leading to non-singular solutions. I will then
present aspects of the cosmological perturbations in various gauges,
addressing several issues including that of stability and the
(in)validity of certain gauges at different points in time across the
cosmological evolution.
For more information, contact:
Tressena Manning
603-646-2854

Events are free and open to the public unless otherwise noted.