Speaker: Huanchen Hu (chair: Felix Pötzl)
Title: Testing higher order GR effects with the Double Pulsar
The Double Pulsar PSR J0737-3039A/B has proven to be an excellent system for high precision tests of General Relativity. With currently the best timing measurement with MeerKAT, the precision of these tests will increase and higher order general relativity effects would become measurable.
In this talk, I will present the goal of this project and focus on investigating the future prospects of measuring the Lense-Thirring effect with MeerKAT, which would lead to the first measurement of the moment of inertia and hence constraining the equation of state of superdense matter. To do so, I developed a simulation code to generate mock data for the Double Pulsar up to 2030, and combine it with the current timing results (Kramer et al., in prep.). I will discuss some preliminary results and the future work.
Speaker: Davit Alkhanishvili (chair: Huanchen Hu)
Title: Computing the matter bispectrum using perturbation theory
Studying the large scale structure of the Universe is one of the main tools of cosmology. It has become widely accepted that gravitational instability plays a central role in giving rise to the structures seen in galaxy surveys. Extracting the wealth of information contained in galaxy clustering to learn about cosmology thus requires a quantitative understanding of the dynamics of gravitational instability. Higher-order statistics like three-point correlation function and its corresponding bispectrum will play a central role in this process once the forthcoming galaxy surveys will measure the bispectrum with sufficient accuracy for the first time.
In this talk I will present the agreement of cosmological matter bispectra to next to leading order in perturbation theory based on various theoretical models with a suite of numerical simulations. Also I will outline some of the difficulties associated with the accurate measurement of the theoretical bispectrum and what are the possible solutions for the future.