Work

Higher-order fermion interactions in effective field theories for phase transitions

Year: 2026

Type: article

Abstract: We investigate the impact of higher-order fermionic deformations in phase transitions analogous to those described by the Bardeen–Cooper–Schrieffer (BCS) theory. Focusing specifically on the 8-fermion interaction, we show that this term can have significant consequences. In certain regions of parameter space, the theory continues to exhibit second-order phase transitions with mean-field critical exponents and the same critical temperature; however, the temperature dependence of the superconducting gap can deviate markedly from conventional BCS behavior. In other regions, the theory exhibits first-order phase transitions. We conclude by discussing potential phenomenological applications of these theories.

Source: Physics Letters B

DOI: 10.1016/j.physletb.2026.140172

Authors: D. Rodriguez-Gomez, J.G. Russo

Institutions: Universidad de Oviedo, Institució Catalana de Recerca i Estudis Avançats, Institut de Ciències del Cosmos, Universitat de Barcelona

Language: English

Topic: Particle physics theoretical and experimental studies

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: diamond

Funders: Ministerio de Ciencia, Innovación y Universidades, Universitat de Barcelona, Agencia Estatal de Investigación