We argue that although at asymptotically high temperatures the quark-gluon plasma (QGP) in bulk behaves as a gas of weakly interacting quasiparticles (modulo long-range magnetism), it is different at temperatures up to few times the critical temperature $T_c$. In particular, we emphasize the role of several zero binding lines on the phase diagrams, below which $\overline{c}c$, light quarks, $gg$ as well as exotic $gq,qq$ bound states exist. Near these lines quasiparticle rescattering is enhanced dramatically, possibly explaining why heavy-ion collisions at the relativistic heavy-ion collider exhibit robust collective phenomena. Although in QCD the coupling constant in the QGP phase reaches only values $g\sim 1$, using Maldacena duality one may study these phenomena in the strong coupling limit $g^2{N}_c⪡1$ in conformal gauge theories at finite temperature [e.g., $\mathcal{N}=4$ supersymmetric Yang-Mills (SUSY YM)]. Trapped atoms is another system which allows us to study strongly interacting matter, in the limit of infinite scattering length.

• Received 11 August 2003

DOI:https://doi.org/10.1103/PhysRevC.70.021901