Light dilaton near critical points in top-down holography

TL;DR

This paper investigates a holographic model of three-dimensional confining field theories near a critical point, revealing a naturally light dilaton state due to a novel stabilization mechanism related to phase transition dynamics.

Contribution

It introduces a holographic framework demonstrating a new stabilization mechanism for a light dilaton near critical points in strongly coupled theories.

Findings

A hierarchy of scales develops near the critical point.

A light dilaton state emerges as a pseudo-Nambu-Goldstone boson.

The phase diagram includes a second-order critical point.

Abstract

We study a class of UV-complete, strongly coupled, confining three-dimensional field theories, that exhibit a novel stabilisation mechanism for the mass of the lightest scalar composite state, relying on the existence of a critical point. The theories admit a holographic dual description in terms of regular backgrounds in eleven-dimensional supergravity. Their phase diagram includes a line of first-order phase transitions ending at the critical point, where the transition becomes of second order. We calculate the mass spectrum of bound states of the field theory, by considering fluctuations around the background solutions, and find that, near the critical point, a hierarchy of scales develops, such that one state becomes parametrically light. We identify this state as the dilaton, the pseudo-Nambu-Goldstone boson associated with the spontaneous breaking of approximate scale invariance. This stabilisation mechanism might be exploited to address hierarchy problems in particle and astroparticle physics.