I am a professor of Physics at Arizona State University. My research is on theory at the intersection of nuclear physics, particle physics and astrophysics/cosmology. Specifically, I work on neutrinos from astrophysical sources and how detecting them can help us learn about fundamental physics. A summary of my activity, including basic bio and full list of publications, can be found on the INSPIRE archive.
Research topics – Neutrinos can be found in the Universe ranging from ultra-low (less than an eV) to ultra-high energies (PeV and beyond). These neutrinos are unique messengers from the depths of the cosmo: they propagate unabsorbed through the densest matter of stellar cores, and from the earliest epochs of the early universe, delivering information that would be unaccessible otherwise. Besides, stars at various stages of their lives (from protostar to black hole formation) offer to us very powerful neutrino beams, that we can use to test the fundamental theory of elementary particles.
Part of my research is on neutrinos from core collapse supernovae, massive stars that die into a powerful explosion. When the star’s core undergoes gravitational collapse, neutrinos carry away most of the released energy, and give a detailed narrative of this process. We can detect them at large neutrino observatories at underground laboratories. It is particularly fascinating that we can detect the diffuse neutrino flux from all the supernovae of the universe, even those located at high redshift from us.
Processes related to stellar birth and stellar death are believed to produce beams of very high energy cosmic ray protons, which then generate neutrinos and gamma rays as a byproduct. Very high energy astrophysical neutrinos, reaching PeV energy, have been detected for the first time by the IceCube detector in 2013. This discovery opens a completely new field of investigation. I am active on various theory aspects of high energy neutrinos; I am especially fascinated by how we can use them to identify the nature of the cosmic ray accelerators.
Occasionally, I work on the theory of neutrinos in the early universe, especially how exotic neutrino properties (new interactions, new neutrino states) can influence the universe that we see today.
Currently, my research is funded by the National Science Foundation.
My team – I work with undergraduate students, graduate students and postdocs. Recent and current group members are Mainak Mukhopadhyay (student) and Zidu Lin (postdoc).
Teaching and other activities – In recent years I have taught Particle and Nuclear physics (undergraduate), Quantum Physics II (undergraduate) and Mathematical Methods for physicists I and II (undergraduate).
News – I post news and updates in the news section, see menu in the upper right corner of this page.