I am currently a Gabilan Assistant Professor of Physics and Astronomy at the University of Southern California. My research focuses on cosmological probes of fundamental physics and aims to unravel some of the biggest mysteries of modern physics: the physical nature of two main constituents of the Universe, dark matter and dark energy. As a postdoc, I was an Eric Schmidt Fellow at the Institute for Advanced Study in Princeton, and I got my PhD in astrophysics at Caltech. I began as an undergrad in astrophysics at the University of Belgrade, Serbia.
As a cosmologist, I study the entire Universe as a physical system. In particular, I combine the tools of theoretical astrophysics, particle physics, and astronomical data analysis in order to probe dark matter, dark energy, and various processes that shaped the Universe before the time of the first stars. My research often involves coming up with new ways of using observations spanning the entire cosmic history---from the cosmic microwave background radiation to populations of dwarf galaxies around the Milky Way---in order to test the fundamental fabric of nature. Below are some research highlights; a number of them are done by students under my supervision.
I'm a member of three science collaborations focused on precision measurements of the CMB: Simons Observatory, CMB-S4 and ACTPol. I also collaborate with the LSST Dark Matter group and co-lead the Likelihood and Theory analysis group for the Simons Observatory. I have previously served on the Science Council for CMB-S4 and have led the Dark Matter working group for the collaboration.
student project: Ethan Nadler (Stanford)
We introduce and apply a new method to constrain dark matter interactions with baryonic particles in the early universe, using a population of satellite galaxies around the Milky Way. We limit dark matter interactions to be 1000 times weaker than previous studies allowed. This work was highlighted in AAS Nova.
student project: Zack Li (Princeton)
We forecast sensitivity of the next-generation cosmic microwave background observations to dark matter physics, and show how to disentangle it from other physical effects. These forecasts fed into the Simons Observatory and CMB-S4 calculations of sensitivity to dark matter.
Here's the first cosmological limit on interactions of sub-proton-mass dark matter particles with baryons. The result was obtained from measurements of the cosmic microwave background anisotropy from the Planck satellite.
student project: Sam Witte (UCLA)
Dark matter direct detection experiments are currently collecting data, in hopes of discovering signal from dark matter particles. In this work, we discuss how Earth's motion around the Sun and the resulting annual modulation of a putative dark-matter signal may be used to distinguish amongst candidate theories that could describe these elusive particles. Check out our dmdd python package.
A proposal for a cool new way to trace tiny magnetic fields in the intergalactic medium during Dark Ages, using future tomographic measurements of the cosmological 21-cm signal from atomic hydrogen. With a 21-cm experiment consisting of 1 square km of dipole antennas, B fields as small as 10^-21 Gauss and coherent over megaparces scales could be within reach.
student project: Karime Maamari (USC)
We compute new bounds on the rate of dark matter-proton scattering at a time when the Universe was ~2 months old. The results are entirely based on linear cosmological perturbation theory and constrain dark matter interaction physics for a broad range of dark matter models. They improve upon previous astrophysical bounds on the scattering cross section by 5 orders of magnitude.
Meet the Group
I run CosmoLab as a weekly Zoom meeting for all USC grads, undergrads, postdocs, and researchers interested in astrophysics research. Contact me if you'd like to join!
I've had the pleasure to work with many very talented students at USC and beyond.
Want to join our team?
If you are interested in collaboration, PhD, or postdoc opportunities, email me at firstname.lastname@example.org. I particularly encourage applications from postdocs and students interested in diversity and inclusion in physics.