Topological fermion condensates from anomalies

TL;DR

This paper demonstrates that certain fermion theories on curved manifolds produce topologically determined condensates from anomalies, applicable in various gravitational contexts, and computable on discretized spaces.

Contribution

It introduces a novel topological mechanism for fermion condensate formation via anomalies in curved spaces, valid on arbitrary triangulations.

Findings

Condensate magnitude depends on volume and Euler characteristic.

Anomaly persists under space discretization, enabling computations on triangulations.

Results are applicable to a broad class of gravitationally coupled fermion theories.

Abstract

We show that a class of fermion theory formulated on a compact, curved manifold will generate a condensate whose magnitude is determined only by the volume and Euler characteristic of the space. The construction requires that the fermions be treated as K\"{a}hler-Dirac fields and the condensate arises from an anomaly associated with a $U(1)$ global symmetry which is subsequently broken to a discrete subgroup. Remarkably the anomaly survives under discretization of the space which allows us to compute the condensate on an arbitrary triangulation. The results, being topological in character, should hold in a wide range of gravitationally coupled fermion theories both classical and quantum