14:00 - 16:30
The London Mathematical Society's annual Mary Cartwright Lecture will take place online on the afternoon of Monday 24 May.
The Mary Cartwright Lecturer is Claudia de Rham, Imperial College London
The accompanying speaker is Ruth Durrer, University of Geneva
This meeting is being held online using Zoom and hosted by the ICMS on behalf of the London Mathematical Society.
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Programme - all times are BST
14.00 Opening of the meeting
Testing General Relativity with Cosmological Observations
Ruth Durrer, University of Geneva
Abstract: General Relativity (GR) is immensely successful. With the late discovery of gravitational waves from black hole and neutron star mergers, it has passed all the tests with flying colours. But so far, all observations have mainly tested the vacuum equations of GR. The most important non-vacuum case, cosmology, is in agreement with GR only after the introduction of two otherwise unknown components, 'Dark Matter' and 'Dark Energy', which amount to about 96% of the total energy budget of the present Universe. This let people in the field question the validity of GR for cosmology. Might it be that GR is flawed on large, cosmological scales? Or in the presence of matter in general? But how can we test Einstein's equation in the presence of matter. Can't we simply move any modification of the Einstein tensor to the right-hand side and call it a 'dark matter/dark energy' component?
In my talk I shall discuss possible ways (partially) out of this dilemma. How to test both, the left and the right-hand side of Einstein's equations with cosmological observations.
15.15 Mary Cartwright Lecture
Analyticity in the Sky with (causal) Diamonds
Claudia de Rham, Imperial College London
Abstract: The direct detection of gravitational waves marks the beginning of a new era for physics and astronomy, with an opportunity to probe gravity at its most fundamental level. I will discuss the subtle interplay between the behaviour of gravity as we observe it at low energies, and its embedding within a meaningful high energy completion. In particular, I will emphasise how the mathematical notion of ‘analyticity’ encodes the physical notion of ‘causality’, and how gravity subtly affects this, a consideration which is particularly relevant for putting constraints on the physical theories we use to describe observations.