Quantum corrections for the phase diagram of systems with competing order

TL;DR

This paper uses quantum field theory to calculate quantum corrections to the phase diagram of systems with competing orders, revealing significant effects on phase boundaries and coexistence regions, relevant to various physical systems.

Contribution

It introduces a method to incorporate quantum corrections into the phase diagram analysis of systems with competing order parameters, including cases with bilinear coupling and symmetry considerations.

Findings

Quantum corrections significantly alter phase boundaries.

Bilinear coupling breaks time-reversal symmetry and affects phase coexistence.

Results are applicable to systems like spin density waves, orbital antiferromagnetism, and heavy fermion compounds.

Abstract

We use the effective potential method of quantum field theory to obtain the quantum corrections to the zero temperature phase diagram of systems with competing order parameters. We are particularly interested in two different scenarios: regions of the phase diagram where there is a bicritical point, at which both phases vanish continuously, and the case where both phases coexist homogeneously. We consider different types of couplings between the order parameters, including a bilinear one. This kind of coupling breaks time-reversal symmetry and it is only allowed if both order parameters transform according to the same irreducible representation. This occurs in many physical systems of actual interest like competing spin density waves, different types of orbital antiferromagnetism, elastic instabilities of crystal lattices, vortices in a multigap SC and also applies to describe the unusual magnetism of the heavy fermion compound URu2Si2. Our results show that quantum corrections have an important effect on the phase diagram of systems with competing orders.