In brief...

I am a cosmologist, which means I use the universe as a laboratory for testing the laws of Nature. My interests include dark energy and modified gravity, cosmic microwave background (CMB), structure formation, cosmic magnetic fields, cosmic strings and other topological defects and their implications for particle physics and cosmology.

Origin of Cosmic Acceleration

The observed acceleration of cosmic expansion could be caused by Dark Energy or be a manifestation of Gravity obeying different laws on cosmological scales. My work involves developing tests of Dark Energy and Modified Gravity theories that can be performed with current and future astronomical data. This line of research requires understanding the capabilities of planned and proposed observations and the extent to which they will help us be distinguish between different theories.

Fundamental Physics from CMB

The Cosmic Microwave Background (CMB) radiation is a snapshot of our Universe at the age of 400,000 years and bears signatures of events that happened before and after. I use the CMB data to gain insight into the fundamental physics in the early and late universe. For example, measurements of the so-called B-mode polarization help us infer information about inflation, primordial magnetic fields and cosmic strings, which could have been created in the aftermath of Inflation or subsequent phase transitions. I am also interested in examining CMB maps for any non-Gaussian features of primordial origin. If found, they would be of profound significance to our understanding of the earliest instants in the history of our universe.

Topological Defects

Topological defects, such as magnetic monopoles, cosmic strings and domain walls, are observed in condensed matter systems and may have been formed during phase transitions at the early stages in the history of the universe. I study magnetic monopoles and domain walls, and their interactions, in the context of grad unified theories (GUTs). Even if we never manage to observe cosmic topological defects, just the fact of their existence as solutions of a field theory is important when working out implications of that theory for the real world.