Search Talks

Large scale structure surveys are one of our primary tools for answering open questions in cosmology like: What is the physics behind dark energy? Is gravity well described by general relativity on cosmological scales, or does that description need to be extended? In order to take full advantage of the information contained in survey data, however, we must ensure that we understand our data’s sensitivity to new physics and that our analyses are not biased by systematics. In my talk I’ll describe work I have been doing in this aim for the Dark Energy Survey (DES). I’ll begin with an introduction to how we can use data from surveys like the DES to test LCDM, including approaches to constraining extensions to general relativity with cosmological data. I’ll use that discussion to motivate a so-called growth-geometry split analysis, a consistency test of LCDM that works by comparing constraints from probes of structure growth and expansion history, and will discuss the status of such an analysis applied to DES data. I’ll also give an overview of the blinding strategy planned for future multi-probe DES cosmology analyses.

I'll discuss an ongoing project of mine with Dinakar Muthiah and Oded Yacobi, which is based on ideas of Kreiman-Lakshmibai-Magyar-Weyman.  It is aimed at developing a "nice" standard monomial theory for the affine Grassmannian in type A, where "nice" means hopefully close in spirit to Hodge's classical standard monomial theory for finite dimensional Grassmannians.

We consider planar hairy black holes in five dimensions with a real scalar field in the Breitenlohner-Freedman window and show that is possible to derive a universal formula for the holographic speed of sound for any mixed boundary conditions of the scalar field. As an example, we locally construct the most general class of planar black holes coupled to a single scalar field in the consistent truncation of type IIB supergravity that preserves the SO(3)xSO(3) R-symmetry group of the gauge theory. We obtain the speed of sound for different values of the vacuum expectation value of a single trace operator when a double trace deformation is induced in the dual gauge theory. In this particular family of solutions, we find that the speed of sound exceeds the conformal value. Finally, we generalize the formula of the speed of sound to arbitrary dimensional scalar-metric theories whose parameters lie within the Breitenlohner-Freedman window