Trouble Finding the Optimal AdS/QCD

TL;DR

This paper investigates the challenges in modeling AdS/QCD by demonstrating how fitting pressure and coupling data simultaneously affects the model's accuracy, highlighting limitations in current bottom-up approaches.

Contribution

It introduces a simple parametric toy model to explore the interplay between pressure and coupling fits in AdS/QCD models.

Findings

Fitting pressure influences the effective coupling in the model.

Simultaneous fitting of pressure and coupling remains problematic.

Current models cannot accurately reproduce both measurements together.

Abstract

In the bottom-up approach to AdS/QCD based on a five-dimensional gravity dilaton action the exponential of the dilaton field is usually identified as the strong or 't Hooft coupling. There is currently no model known which fits the measurements of the running coupling and lattice results for pressure at the same time. With a one parametric toy model we demonstrate the effect of fitting the pressure on the coupling and vice versa.