The Heavy-Ion Physics Programme with the ATLAS Detector

The CERN LHC will collide lead ions at $\sqrt{s}=5.5$ TeV per nucleon pair and will provide crucial information about the formation of a quark--gluon plasma at the highest temperatures and densities ever created in the laboratory. We report on an updated evaluation of the ATLAS potential to study heavy--ion physics. The ATLAS detector will perform especially well for high $p_T$ phenomena even in the presence of the high--multiplicity soft background expected from lead-lead collisions, and most of the detector subsystems retain their nearly full capability. ATLAS will study a full range of observables which characterize the hot and dense medium formed in heavy--ion collisions. In addition to global measurements such as particle multiplicities and collective flow, heavy--quarkonia suppression, jet quenching and the modification of jets passing in the dense medium will be accessible. ATLAS will also study forward physics and ultraperipheral collisions using Zero Degree Calorimeters.