The Particle Theory Group applies sophisticated analytical and numerical techniques to a wide range of problems in quantum field theory and mathematical physics. Research areas include: quantum field theory, lattice gauge theory, quark matter at ultra-high temperature and density, statistical field theory, and phase transitions.

Carl Bender works in quantum field theory, asymptotics, perturbation theory, semi-classical methods, nonperturbative methods, and mathematical physics. He has achieved particular prominence as the originator of the new field of complex quantum mechanics.

Claude Bernard's area is lattice gauge theory, strong interactions and their effect on the weak interactions, physics of heavy quarks, and computational physics. He is a senior member of the MILC collaboration, a multi-university collaboration that is playing a leading role in the simulation of quantum chromodynamics.

Michael Ogilvie works on a wide range of topics in quantum field theory and statistical mechanics, with an emphasis on strong-interaction physics. His areas of expertise include QCD at finite temperature and density, lattice gauge theory, confinement, chiral symmetry breaking, and non-equilibrated systems.

Mark Alford works on strong-interaction physics, particularly the properties of quark matter, and the development of signatures by which it might be detected in neutron stars. He is one of the world's leading researchers in the area of color superconductivity in quark matter.

Francesc Ferrer works in astroparticle physics and theoretical cosmology. He studies the composition and evolution of the universe and the implications for cosmology of models of particle physics beyond the Standard Model. He focuses on the dark matter composing galactic halos, and the cosmological role of topological defects and other extended field configurations.