Monopoles and Holography

TL;DR

This work presents a holographic realization in $AdS_4$ of a magnetically driven, spontaneously formed crystalline ground state due to bulk ’t Hooft–Polyakov monopoles. The monopoles assemble into a planar wall that induces a bulk lattice and a boundary with translational symmetry breaking, while the IR region exhibits magnetic screening and an emergent $SU(2)$ global symmetry. Using a probe Abelian approximation and then incorporating gravitational backreaction, the authors map the zero-temperature phase structure and finite-temperature melting, revealing a first-order wall–black hole transition and a rich boundary RG flow connecting a magnetically induced crystal to an emergent IR conformal regime. The results offer a magnetic analogue of holographic superconductors and illuminate how bulk solitons can generate boundary lattice order and novel IR dynamics with potential connections to strange metal phenomenology.

Abstract

We present a holographic theory in AdS_4 whose zero temperature ground state develops a crystal structure, spontaneously breaking translational symmetry. The crystal is induced by a background magnetic field, but requires no chemical potential. This lattice arises from the existence of 't Hooft-Polyakov monopole solitons in the bulk which condense to form a classical object known as a monopole wall. In the infra-red, the magnetic field is screened and there is an emergent SU(2) global symmetry.