In brief...
I work in particle cosmology with interests in the
composition and evolution of the Universe, dark energy and modified
gravity, observational probes of physics beyond Standard Model,
topological defect solutions in quantum field theory and their
implications for particle physics and cosmology, cosmic (super)strings
and other characteristics of Brane Inflation, cosmological magnetic
fields, cosmic microwave background (CMB), and tests of cosmological
Gaussianity.
Origin of Cosmic Acceleration
The cosmic acceleration could be caused by Dark Energy or be a
manifestation of Gravity obeying different laws on largest scales. I am
interested in developing tests of Dark Energy that will maximally
utilize the information contained in the data. I have also studied some
of the models of modified gravity with the focus on their predictions
for the clustering of cosmic matter. This line of research involves
understanding the capabilities of planned and proposed observations and
making detailed forecasts of 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,
looking for B-mode polarization from cosmic strings produced at the end
of Inflation, or signatures of magnetic fields left after Baryogenesis.
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. With Tanmay Vachaspati, I studied monopoles and domain
walls, and their interactions, in the context of grad unified theories
(GUTs). We found novel types of solutions and interesting interactions
in a variety of systems. Even if we never manage to observed
topological defects, just the fact of their existence as solutions of a
field theory is important when working out the implications of that
theory for the real world.