Linear confinement and AdS/QCD

Abstract

In a theory with linear confinement, such as QCD, the masses squared m 2 n,S of mesons with high spin S or high radial excitation number n are expected, from semiclassical arguments, to grow linearly with S and n. We show that this behavior can be reproduced within a putative 5-dimensional theory holographically dual to QCD (AdS/QCD). With the assumption that such a dual theory exists and describes highly excited mesons as well, we show that asymptotically linear m 2 spectrum translates into a strong constraint on the infrared behavior of that theory. In the simplest model which obeys such a constraint we find m 2 n,S ∼ (n + S).

AdS/QCD phenomenological models from a back-reacted geometry

“…As for the resonances, in [22] it was shown that one can get linear confinement by including a quadratic dilaton Φ ∼ z 2 in the pure AdS background (see also [26] for a phenomenological treatment including a UV cutoff). The peculiar z 2 dependence of the dilaton is far from clear.…”

“…Indeed we will show that this can be done consistently while finding the back-reaction on the geometry. The second option may have significant implications in the context of linear confinement where a specific IR behavior for the metric and dilaton have been discussed in [22]. Finding a back-reacted solution which gives this is an important goal and is discussed more in section 4.…”

“…Many efforts have been made in constructing a holographic dual of QCD. See [13,14,15,16,17,18,19,20,21,22,23,24,25,26] and references therein for various approaches. Usually in these models, the background manifold is chosen to be AdS, which means one did not consider the effects of the condensates.…”

Mesons in gauge/gravity duals

“…In [265] it was pointed out though that if the dilaton grows as 1 r 2 in the IR the potential V will be of the form…”

Heavy quark potential from deformed AdS5 models

“…by deriving holographic QCD from string theory [23][24][25][26], and bottom-up approach, i.e. by examining holographic QCD from experimental data and lattice results [16,[27][28][29][30][31].…”