Field Theories Without a Holographic Dual

TL;DR

This paper discusses the conditions under which certain field theories, used to model quark-gluon plasmas, have holographic duals, emphasizing the importance of angular momentum effects for RHIC plasmas and questioning the duality for LHC plasmas.

Contribution

It clarifies when field theories relevant to quark-gluon plasmas possess holographic duals, highlighting the role of angular momentum in establishing duality for RHIC but not for LHC.

Findings

Holographic duals can exist for RHIC plasmas with proper angular momentum considerations.

The duality for LHC plasmas remains uncertain due to different conditions.

Angular momentum effects are crucial in holographic modeling of plasmas.

Abstract

In applying the gauge-gravity duality to the quark-gluon plasma, one models the plasma using a particular kind of field theory with specified values of the temperature, magnetic field, and so forth. One then assumes that the bulk, an asymptotically AdS black hole spacetime with properties chosen to match those of the boundary field theory, can be embedded in string theory. But this is not always the case: there are field theories with no bulk dual. The question is whether these theories might include those used to study the actual plasmas produced at such facilities as the RHIC experiment or the relevant experiments at the LHC. We argue that, \emph{provided} that due care is taken to include the effects of the angular momentum associated with the magnetic fields experienced by the plasmas produced by peripheral collisions, the existence of the dual can be established for the RHIC plasmas. In the case of the LHC plasmas, the situation is much more doubtful.