A scaling limit of $\mathrm{SU}(2)$ lattice Yang-Mills-Higgs theory
Sourav Chatterjee
TL;DR
This work constructs rigorous scaling limits for lattice Yang--Mills--Higgs theories in dimensions $d\ge 2$, proving that under a precise scaling of the gauge coupling $g$ and Higgs length $\alpha$, with $\alpha g$ tied to the lattice spacing $\varepsilon$, the gauge-fixed lattice fields converge to Euclidean Proca fields. In the Abelian $\mathrm{U}(1)$ case, the stereographic projections of link variables yield a single massive Gaussian field in the continuum limit with mass determined by $c^2$, while in the non-Abelian $\mathrm{SU}(2)$ case the limit is a triple of independent massive Gaussian fields, evidencing mass generation via the Higgs mechanism at the scaling limit. These are the first rigorous constructions of Gaussian scaling limits for non-Abelian lattice YM theories in $d>2$, and they provide a concrete step toward the elusive non-Gaussian continuum Yang--Mills scaling limit, leaving open the full non-Gaussian regime and extensions to other gauge groups and potentials. The results highlight the central role of the product $\alpha g$ in controlling the continuum limit and offer a quantitative framework for mass generation arising from the Higgs mechanism in lattice gauge theories. Further work is needed to understand slower decay regimes of $g$, general Higgs potentials, and the existence of non-Gaussian scaling limits.
Abstract
The construction of non-Abelian Euclidean Yang-Mills theories in dimension four, as scaling limits of lattice Yang-Mills theories or otherwise, is a central open question of mathematical physics. This paper takes the following small step towards this goal. In any dimension $d\ge 2$, we construct a scaling limit of $\mathrm{SU}(2)$ lattice Yang-Mills theory coupled to a Higgs field (under the degenerate potential) transforming in the fundamental representation of $\mathrm{SU}(2)$. After unitary gauge fixing and taking the lattice spacing $\varepsilon\to 0$, and simultaneously taking the gauge coupling constant $g\to 0$ and the Higgs length $α\to \infty$ in such a manner that $αg$ is always equal to $c\varepsilon$ for some fixed $c$ and $g= O(\varepsilon^{50d})$, a stereographic projection of the gauge field is shown to converge to a scale-invariant massive Gaussian field. This gives the first construction of a scaling limit of a non-Abelian lattice Yang-Mills theory in a dimension higher than two, as well as the first rigorous proof of mass generation by the Higgs mechanism in such a theory. Analogous results are proved for $\mathrm{U}(1)$ theory as well. The question of constructing a non-Gaussian scaling limit remains open.
