Density, short-range order, and the quark-gluon plasma

We study the thermal part of the energy density spatial correlator in the quark-gluon plasma. We describe its qualitative form at high temperatures. We then calculate it out to distances approximate to 1.5/T in SU(3) gauge theory lattice simulations for the range of temperatures 0.9 <= T/T-c <= 2.2. The vacuum-subtracted correlator exhibits nonmonotonic behavior, and is almost conformal by 2T(c). Its broad maximum at r approximate to 0.6/T suggests a dense medium with only weak short-range order, similar to a nonrelativistic fluid near the liquid-gas phase transition, where eta/s is minimal.