Article,
Mesons in Gauge/Gravity Duals - A Review
The European Physical Journal A, 35 (1): 81--133 (Dec 17, 2007)
DOI: 10.1140/epja/i2007-10540-1
Abstract
We review recent progress in studying mesons within gauge/gravity duality, in
the context of adding flavour degrees of freedom to generalizations of the
AdS/CFT correspondence. Our main focus is on the `top-down approach' of
considering models constructed within string theory. We explain the
string-theoretical constructions in detail, aiming at non-specialists. These
give rise to a new way of describing strongly coupled confining large N gauge
gauge theories similar to large N QCD. In particular, we consider gravity dual
descriptions of spontaneous chiral symmetry breaking, and compare with lattice
results. A further topic covered is the behaviour of flavour bound states in
finite temperature field theories dual to a gravity background involving a
black hole. We also describe the `bottom up' phenomenological approach to
mesons within AdS/QCD. -- Some previously unpublished results are also
included.
