Boson Condensates at the Relativistic Heavy Ion Collider (RHIC)
Bosonic condensates formed from the pairing of spontaneously created quarks and antiquarks are fundamental features of the vacuum and the structure of elementary particles such as the nucleon; such condensates underlie the spontaneous breaking of the chiral symmetry (the symmetry between right- and left-handedness) of the strong interactions. One of the important aims of ultrarelativistic heavy ion collisions at the RHIC and, starting in 2007, at the Large Hadron Collider (LHC) is to produce chirally restored matter in the form of quarkgluon plasmas. There, one is asking the opposite of the question asked in condensed matter physics—namely, What are the properties of Bose-Einstein “de-condensed” matter?
AMO science enjoys a very close interaction and synergy between theory and experiment, which benefit each other in numerous ways. Indeed, the hallmark of science is the parallel hand-in-hand progress that theory and experiment make together, each playing a vital role, sometimes with theory leading the way, other times with experiment doing so. Nowhere is this more true than for the areas of research described in this chapter.
While experimental breakthroughs constantly challenge theorists, the reverse is also true, with theorists suggesting new experimental paths and novel ways to reach exciting regimes where new physics can be explored. For example, the possibility of using Feshbach resonances to achieve new regimes of ultracold physics was suggested by theorists. This proposal led to the creation of molecular condensates and opened the way to one of the most exciting recent discoveries in AMO physics: observation of the crossover between Bose condensation and Cooper pairing of fermions. As a result, there is a new link between atomic and condensed matter physics. Likewise, the idea of using ultracold atoms trapped in optical lattices to study the transition between superfluidity and another quantum state called a Mott insulator originated in theoretical studies. The experimental realization of these states opens the way to exciting new potential approaches to quantum information processes and to the realization of quantum simulators to investigate in detail key problems in condensed matter physics. Nonlinear atom optics and the generation of vortex lattices in BECs, along with many other examples of theory leading experiment, illustrate that in AMO science, there is close cooperation between theory and experiment.