High Energy Theory, Particle Astrophysics and Early Universe Cosmology



Born and raised in Minnesota, I completed a Ph.D. at the University of Washington in 2006.  My work there focused on neutrino astrophysics and cosmology. During this time I also developed the ``Hidden Valley'' models which opened new directions to search for low mass hidden sectors at colliders such as the LHC.  These classes of models also became central to my subsequent work in dark matter, including Asymmetric Dark Matter and hidden sector dark matter more generally.  I became a postdoc at the University of Wisconsin, Madison and then the David Schramm Fellow at Fermi National Accelerator Laboratory.  During this time, I focused on developing concrete models of hidden sector dark matter. I instigated theories of ``Asymmetric Dark Matter'' and established techniques to build models of natural low mass hidden dark matter sector. 

In 2009, I became an Assistant Professor, and then in 2012 an Associate Professor, at the University of Michigan, where I developed these theories in the context of anomalies from direct detection experiments. I remain interested in connecting these theories to physics at the LHC (including the Higgs boson) and to astrophysical objects such as neutron stars and white dwarves.  In 2014, I moved to Berkeley where I focused on proposing new ideas to detect light dark matter. Since 2019 I am Professor of Theoretical Physics at Caltech. I remain interested in how we can utilize a variety of theoretical and experimental probes to solve some of nature's deepest mysteries, including the theory of dark matter. Most recently, I have been considering observational signatures of holographic theories of quantum gravity.

Abbreviated CV

Academic Positions

2019 - Present :: Professor of Theoretical Physics, Caltech.

2017 - Present :: Fellow of the American Physical Society

2018 :: Scientific Associate, CERN.

2014 - 2019 :: Senior Scientist, Laurence Berkeley National Laboratory, UC Berkeley.

2014 - 2017 :: Exceptional PI, UC Berkeley.

2013 - 2014 :: Associate Professor, Department of Physics, University of Michigan.

2009 - 2012 :: Assistant Professor, Department of Physics, University of Michigan.

2012 - 2013 :: Member, Institute for Advanced Study. Princeton, NJ.

2008- 2009 :: David Schramm Fellow, Fermi National Accelerator Laboratory, Particle Astrophysics Center.

2006 - 2008 :: Postdoc, Wisconsin Phenomenology Institute, University of Wisconsin, Madison.

2002 - 2006 :: Research Assistant, Institute for Nuclear Theory, University of Washington. 


2001 - 2006      University of Washington                        
                           Seattle, WA, USA
                           Ph.D., Department of Physics, June 2006
                           Advisor: David B. Kaplan

1997 - 2001      Bethel University
                           St. Paul, MN, USA
                           B.S. in Physics, Summa Cum Laude, 2001

In the Press

Berkeley Leans into Search for Light Dark Matter,” 10 June 2019, Symmetry Magazine.

In Search for Unseen Matter, Physicists Turn to Dark Sector,” 24 March 2017, Science.

"New Techniques Could Target More Exotic Dark Matter," 13 October 2016, Scientific American.

"Physics - Synopsis: Spotting Dark Matter with Supermaterials,"14 September 2016, APS Physics.

"Hunting for Dark Matter's Hidden Valley," 24 May 2016 in Berkeley Lab News Center.

"Physicists Widen the Search for Dark Matter Particles," June 2014, APS News.

"Portraits of darkness," 31 August 2013 in New Scientist.

"Dark Matter Hunt Appears to be Zeroing In on a Leading Contender," 22 July 2013 in Wired Science.

"Tentative dark matter hints with shadow dark sector," 16 April 2013 in New Scientist.

"Peering Back 13 Billion Years, Through a Gravitational Lens," 29 April 2011 in Science.

"The dark side of antimatter," by Rachel Courtland, 25 November 2010 in New Scientist.

"Quirky particles could explain universe's missing mass," by Jon Cartwright, 1 June 2010 in Physics World.

"Super-sensitive tool key to dark matter claim," 9 July 2008 in Nature.

Personal Interests

I enjoy hiking, climbing, sailing, and classical music. Here are a few photos.