Our group studies the properties of matter in the hottest and densest conditions attainable in a lab. Our experiment is the Compact Muon Solenoid (CMS) which detects particles produced from high-energy proton-proton (pp) and lead-lead (PbPb) nuclei collisions produced by the Large Hadron Collider (LHC) located near Geneva, Switzerland.

The PbPb collisions are our group’s primary focus. When two ultra-relativistic nuclei collide, they deposit a fraction of their energies into the space between them, which results in heating up the vacuum to temperatures around one million times hotter than the center of the sun. That super-hot vacuum is believed to create what is called a Quark Gluon Plasma (QGP), a system of deconfined, strongly interacting, quarks, anti-quarks, and gluons in thermal equilibrium.

This type of matter, believed not to have existed outside particle accelerators since a small fraction of a second after the big bang, has some very interesting properties. Initially this matter was expected to be a weakly interacting gas, which is where the “Plasma” part of the QGP name comes from. However when this matter was first produced and studied at the Relativistic Heavy Ion Collider (RHIC) it came as a big surprise to find out it was much closer to a perfect liquid, with a viscosity to entropy density ratio near the theoretical lowest possible value. Understanding this unique state of matter provides insights to the state and evolution of the universe in its very early stages, as well as other states of matter in condensed matter physics, atomic physics, and black hole physics which share common features.