Nishant Agarwal
I am a fourth year graduate student in Astronomy at Cornell University and am working with Prof. Rachel Bean. My chief interest is in theoretical cosmology.
I am currently working on trying to understand the nature of dark energy as a modification to Einstein's gravity. Dark energy is the name given to the mysterious force/energy that drives the current acceleration of the universe. Because of the simple reason that gravity is attractive we would expect the expansion of the universe to slow down with time. The acceleration can be attributed to some strange form of matter/energy which has negative pressure. It can also be explained by modifying the way that gravity behaves on large scales. I am currently working on higher-dimensional modifications to gravity. In the past I have worked on scalar-tensor modified gravity theories.
I am also interested in the early-time acceleration of our universe, as described by inflation. The inflationary model proposes that the universe had a very rapid exponential expansion in its early history just after the big bang. This rapid expansion is needed in order to explain some standard problems in cosmology like the horizon problem and the flatness problem. Inflation is accepted as a part of the standard model of cosmology but lacks a firm physical explanation to its origin. My work has focused on imposing observational constraints on a general single scalar field Lagrangian describing inflation.