Gauge theory in de Sitter space-time from a holographic model

TL;DR

This paper explores the behavior of Yang-Mills theory with flavor quarks in de Sitter space using a holographic supergravity model, revealing insights into quark confinement, meson stability, and the influence of the cosmological constant.

Contribution

It introduces a holographic model for YM theory in de Sitter space, analyzing quark dynamics, meson spectra, and the role of gauge condensates, highlighting differences from finite temperature scenarios.

Findings

Quarks are not confined in de Sitter space.

Stable meson states can exist at very small cosmological constants.

Gauge field condensates significantly influence quark properties.

Abstract

Yang-Mills theory with flavor quarks in the dS${}_4$ is studied through the dual supergravity in the AdS${}_5\times S^5$ background with non-trivial dilaton and axion. The flavor quarks are introduced by embedding a probe D7 brane. We find that the dynamical properties of YM theory in the dS${}_4$ are similar to the case of the finite temperature theory given by the 5d AdS-Schwarzschild background. In the case of dS${}_4$, however, contrary to the finite temperature case, the gauge field condensate plays an important role on the dynamical properties of quarks. We also give the quark-antiquark potential and meson spectra to find possible quark-bound states. And we arrive at the conclusion that, while the quarks are not confined in the dS${}_4$, we could find stable meson states at very small cosmological constant as expected in the present universe. But there would be no hadrons at early universe as in the inflation era.