In 2005, scientists at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory reported creating QGP by smashing gold atoms together at nearly the speed of light. The only place in the universe where QGP exists is inside high-speed accelerators, for the briefest flashes of time. However, the actual behavior of quarks and gluons is difficult to study because they are confined within heavier particles. Their interactions are governed by a theory known as quantum chromodynamics, developed in part by MIT professors Jerome Friedman and Frank Wilczek, who both won Nobel prizes for their work. Quarks and gluons, though they make up protons and neutrons, behave very differently from those heavier particles. “If you’re interested in the properties of the microseconds-old universe, the best way to study it is not by building a telescope, it’s by building an accelerator,” says Krishna Rajagopal, an MIT theoretical physicist who studies QGP.
Over the past decade, physicists around the world have been trying to re-create that soup, known as quark-gluon plasma (QGP), by slamming together nuclei of atoms with enough energy to produce trillion-degree temperatures.
A few microseconds later, those particles began cooling to form protons and neutrons, the building blocks of matter. For a few millionths of a second after the Big Bang, the universe consisted of a hot soup of elementary particles called quarks and gluons.