Debye screening mass near deconfinement from holography

In this paper the smallest thermal screening mass associated with the correlator of the CT-odd operator, ∼TrFμνF∼μν, is determined in strongly coupled non-Abelian gauge plasmas which are holographically dual to nonconformal, bottom-up Einstein+scalar gravity theories. These holographic models are constructed to describe the thermodynamical properties of SU(Nc) plasmas near deconfinement at large Nc, and we identify this thermal mass with the Debye screening mass mD. In this class of nonconformal models with a first-order deconfinement transition at Tc the Debye screening mass mD displays the same behavior found for the expectation value of the Polyakov loop (which we also compute) jumping from zero below Tc to a nonzero value just above the transition. In the case of a crossover phase transition, mD/T has a minimum similar to that found for the speed of sound squared cs2. This holographic framework is also used to evaluate mD as a function of η/s in a strongly coupled conformal gauge plasma dual to Gauss-Bonnet gravity. In this case, mD/T decreases with increasing η/s in accordance with extrapolations from weak coupling calculations.