  Run 1 at the LHC was very successful with the discovery of a new boson. The
boson's properties are found to be compatible with those of the Standard Model
Higgs boson. It is now revealing the mechanism of electroweak symmetry breaking
and (possibly) the discovery of physics beyond the Standard Model that are the
primary goals of the just restarted LHC. The ultimate precision will be reached
at the High-Luminosity LHC phase with a proton-proton centre-of-mass energy of
14 TeV. In this contribution physics prospects are presented for ATLAS for the
integrated luminosities 300/fb and 3000/fb: the ultimate precision attainable
on measurements of the Higgs boson couplings to elementary fermions and bosons,
its trilinear self-coupling, as well as perspectives on the searches for
supersymmetric partners associated with the Higgs boson. Benchmark studies are
presented to show how the sensitivity improves at the future LHC runs. For all
these studies, a parametrised simulation of the upgraded ATLAS detector is used
and expected pileup conditions are accounted for.
