I work on a broad range of topics in the very early universe, focussing primarily on the physics of inflation and their imprint on the cosmic microwave background radiation, the reheating phase transition that must end inflation and begin the hot Big Bang, and the connections between high-energy particle physics and the early universe.
Much of my research has been motivated by the electroweak hierarchy problem and the strong CP problem. I have worked on the physics of the Higgs boson, particularly in the context of supersymmetric solutions to the hierarchy problem; the cosmology of axion solutions to the strong CP problem and other axion-like dark matter candidates; and the experimental probes of other mechanisms that could address strong CP. I am also interested in more theoretical aspects of quantum field theory, particularly regarding nonperturbative phenomena in gauge theories, and in constraining effective field theories with ultraviolet consistency conditions.
A large part of my research concerns lattice QCD calculations that are needed to interpret measurements in high energy experiments, particularly in flavor physics. For example, the anomalous magnetic moment of the muon provides one of the single strongest hints for new physics in this program in the form of a tantalizing tension between Standard Model theory and experiment of 3-4 standard deviations. The Fermilab g-2 experiment has recently started taking data, with the goal of reducing the experimental errors by a factor of four. However, the theoretical uncertainties, which are dominated by the hadronic contributions, must also be reduced, in order unambiguously discover if new physics contributes to this quantity. Other recent research interests also include using quantum simulators and quantum computing to study novel Quantum Field Theories.
In my opinion, the most robust collection of data we have to guide the search for physics beyond the Standard Model is the evidence for the existence of dark matter. My research is focused on designing new experiments to detect dark matter, often in collaboration with condensed matter physicists.
I work on a broad range of topics in particle physics beyond the Standard Model. My overarching interests are to develop new ways to discover and understand footprints of new physics, in systems that range from colliders to the cosmos. Major research focuses include Higgs physics, challenging signatures at high-energy colliders, dark matter, and the thermal histories of dark sectors.
Alumni - Graduate Students
Name, Year Ph.D. received (Advisor), first position after leaving, permanent academic position
- Pranjal Ralegankar, Ph.D. 2022 (Shelton and Adshead), SISSA (Trieste, Italy)
- Christian Gaidau, Ph.D. 2021 (Shelton)
- Dong Xu, Ph.D. 2021 (Shelton)
- Chia-Cheng Chang, Ph.D. 2015 (El-Khadra), LBL, Theory group
- Harrison Mebane, Ph.D. 2013 (Willenbrock)
- Will Link, Ph.D. 2012 (Willenbrock)
- Chris Bouchard, Ph.D. 2011 (El-Khadra), Ohio State University, Glasgow University
- Cen Zhang, Ph.D. 2011 (Willenbrock), Louvain U., IHEP/CAS (Beijing, China)
- Rob Putman, Ph.D. 2010 (Willenbrock)
- R. Todd Evans, Ph.D. 2008 (El-Khadra), Universität Regensburg, TACC (UT Austin)
- Josh Sayre, Ph.D. 2008 (Willenbrock), Pittsburgh U.
- Thomas McElmurry, Ph.D. 2006 (Willenbrock), University of Wisconsin
- Damien Menscher, Ph.D. 2005 (El-Khadra), Google
- Mike Niczyporuk, Ph.D. 2002 (Willenbrock), MIT (Pappalardo Fellow)
- Kevin Paul, Ph.D. 2002 (Willenbrock), UIUC
- Zack Sullivan, Ph.D. 1998 (Willenbrock), Fermilab
- Martin Smith, Ph.D. 1998 (Willenbrock)
Alumni - Postdoctoral Researchers
name, last year at Illinois, first position after leaving, permanent academic position
- Kaloian Lozanov, 2022, IPMU
- Benjamin Lillard, 2022, University of Oregon
- Nicolas Fernandez, 2022, Rutgers University
- Zechariah Gelzer, 2021
- Jonathan Kozaczuk, 2019, UCSD
- Lauren Pearce, 2019, Penn State - New Kensington
- Jared Evans, 2017, U. Cincinnati
- Evangelos Sfakianakis, 2017, Nikhef
- Céline Degrande, 2013, Durham, Catholic University Louvain
- Daping Du, 2013, Syracuse University
- Olivier Mattelaer, 2013, Catholic University Louvain, Catholic University Louvain
- Elizabeth Freeland, 2011, Benedictine College (Faculty, School of the Art Institute of Chicago)
- Nicolas Greiner, 2011, MPI Munich
- Elvira Gamiz, 2009, Fermilab, University of Granada
- Soren Wiesenfeldt, 2007, Karlsruhe
- M. Bugra Oktay, 2004, Trinity College (Dublin)
- Fabio Maltoni, 2002, Rome U., Catholic University Louvain/Bologna
- Zbigniew Sroczynski, 2000, Liverpool
- Tim Stelzer, 1998, UIUC (PER faculty), UIUC (Physics Education Research)
- James Simone, 1996, Fermilab, Fermilab (Senior Scientist)