Higher-Order Fermion Interactions in Effective Field Theories for Phase Transitions

Diego Rodriguez-Gomez; Jorge G. Russo

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arXiv · 2507.11624

Higher-Order Fermion Interactions in Effective Field Theories for Phase Transitions

Diego Rodriguez-Gomez·Jorge G. Russo

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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.

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Diego Rodriguez-Gomez, Jorge G. Russo. 2025-07-15. Higher-Order Fermion Interactions in Effective Field Theories for Phase Transitions. https://arxiv.org/abs/2507.11624

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