Talks

I will discuss the role(s) of the Immirzi parameter in Loop Quantum Gravity, insisting on the Poisson algebra formed by Thiemann's complexifier, the volume and the Hamiltonian constraint. In particular, we will see how loop quantum cosmology is a direct quantization of this CVH Poisson algebra and how cosmological evolution amounts to a flow in the Immirzi parameter.

I will first show that a number of persistent astrophysical puzzles, including missing pulsars in the galactic center, fast radio bursts, the abundance of r-process elements, and the type Ia supernova progenitor problem, may all be an emerging signature of dark matter. I will address some theoretical implications and new astrophysical phenomena -- for example "quiet kilonovae" and "r-process donuts" -- associated with this dark matter. Then, I will describe a newly discovered effect, that dark matter crashing into neutron stars warms them to infrared temperatures detectable with the Thirty Meter, European Extremely Large, and James Webb Space telescopes.

Gravitational lensing is one of the primary investigation tools of all current and future wide field surveys. In this talk I will review its current status (with the Kilo Degree Survey (KiDS)) and show what unique cosmological information it gives us. Lensing is not limited to a, low redshift, dark universe probe, it can also be used as a tool to probe baryons and nicely work in synergy with baryonic probes (e.g. CMB, Xray, tSZ, HI). I will show some of the work in progress to help constraining Active Galactic Nuclei feedback

Dark matter is all around us, however its particle physics nature is still mysterious. Searches for dark matter have largely focused on candidates with weak scale interactions to the standard model particles, the so-called WIMP paradigm. However, the parameter space of the WIMP paradigm is becoming increasingly constrained by both the LHC and direct detection experiments. Another possibility that is well motivated both theoretically and observationally is to have a dark sector connected with the visible one via a mediator whose coupling to the visible one is tiny. In this talk, based on my own work, I will discuss models in this direction and how to search for signals from the dark sector using various experiments including particle accelerators, dark matter direct detection experiments, cosmic ray experiments, and cosmic microwave background observation.