English

Topological effect on order-disorder transitions in U(1) sigma models

Strongly Correlated Electrons 2025-06-19 v3 Disordered Systems and Neural Networks Quantum Gases Superconductivity

Abstract

U(1) non-linear sigma model (NLSM) with a one-dimensional (1D) Berry phase is studied by a renormalization group theory. Order-disorder transition in U(1) NLSMs in D ⁣ (2)D \!\ (\ge 2)-dimensional space (d+1d+1-dimensional spacetime; d1d\ge 1) is instigated by the proliferation of vortex excitations, where the 1D Berry phase term confers finite phase factors upon those vortex excitations that have finite projection in a subspace complementary to a topological direction with the 1D Berry phase. A destructive interference effect caused by the phase factors may help to develop an intermediate quasi-disorder phase between ordered and disorder phases, which has a divergent order-parameter correlation length along the topological direction, and a finite correlation length along the other directions. In order to explore such a possibility in D=3D=3, we develop a perturbative renormalization group theory of a 3D model of vortex loops, in which loop segments interact via a 1/r1/r Coulomb interaction. We derive renormalization group (RG) equations among vortex-loop fugacity, Berry phase term, and the Coulomb potential. Approximate analyses of the RG equations show that near an order-disorder transition point, vortex loops are anomalously elongated along the topological direction. Utilizing a duality mapping to a lattice model of a type-II superconductor under a magnetic field, we also argue that a global phase diagram of the 3D U(1) sigma model with 1D Berry phase must have the quasi-disorder phase between ordered and disorder phases.

Keywords

Cite

@article{arxiv.2503.18969,
  title  = {Topological effect on order-disorder transitions in U(1) sigma models},
  author = {Ryuichi Shindou and Pengwei Zhao},
  journal= {arXiv preprint arXiv:2503.18969},
  year   = {2025}
}

Comments

29 pages, 5 figres. The key findings of the paper are newly summarized in Section I; detailed derivations in Section IV are transferred in Appendices; discussions on a discrepancy between RG analyses and duality argument are further revised

R2 v1 2026-06-28T22:32:47.414Z