  In this thesis, QCD is studied from three different directions, with one
overarching theme: holography. The holographic duality allows certain strongly
coupled QFTs to be described in terms of much simpler classical gravity in one
dimension more. The first direction from which QCD is studied in this thesis is
by examining the effects of an external magnetic field on a particular
holographic model of QCD, yielding interesting qualitative insight. The second
approach examines how, in the same model, one can describe dense baryonic
configurations, providing a new way to study the matter composing neutron
stars. Indeed, the equation of state produced in this way is subsequently used
to compute several neutron star properties which are observable, or will be in
the near future. The last direction contains no holographic computations per
se, but does incorporate several qualitative insights from holography into a
new heavy ion code called Trajectum. This will in the near future be used to
perform a Bayesian analysis, whereby it is hoped that these qualitative
insights from holography can be tested on experimental data, to see how well
the ideas coming from holography match up with experiment.
