Continuous order-to-order quantum phase transitions from fixed-point annihilation

Research output: Contribution to journalResearch articleContributedpeer-review

Abstract

A central concept in the theory of phase transitions beyond the Landau-Ginzburg-Wilson paradigm is fractionalization: the formation of new quasiparticles that interact via emergent gauge fields. This concept has been extensively explored in the context of continuous quantum phase transitions between distinct orders that break different symmetries. We propose a mechanism for continuous order-to-order quantum phase transitions that operates independently of fractionalization. This mechanism is based on the collision and annihilation of two renormalization group fixed points: a quantum critical fixed point and an infrared stable fixed point. The annihilation of these fixed points rearranges the flow topology, eliminating the disordered phase associated with the infrared stable fixed point and promoting a second critical fixed point, unaffected by the collision, to a quantum critical point between distinct orders. We argue that this mechanism is relevant to a broad spectrum of physical systems. In particular, it can manifest in Luttinger fermion systems in three spatial dimensions, leading to a continuous quantum phase transition between an antiferromagnetic Weyl semimetal state, which breaks time-reversal symmetry, and a nematic topological insulator, characterized by broken lattice rotational symmetry. This continuous antiferromagnetic-Weyl-to-nematic-insulator transition might be observed in rare-earth pyrochlore iridates R 2 Ir2O7. Other possible realizations include kagome quantum magnets, quantum impurity models, and quantum chromodynamics with supplemental four-fermion interactions.

Details

Original languageEnglish
Article number098001
JournalReports on progress in physics
Volume88
Issue number9
Publication statusPublished - 15 Sept 2025
Peer-reviewedYes

External IDs

PubMed 40897199

Keywords

ASJC Scopus subject areas

Keywords

  • fixed-point annihilation, Luttinger semimetals, nematic topological insulator, pyrochlore iridates, quantum criticality, Weyl semimetal