Mechanism of the FL*–stripy SDW confinement crossover

Elucidate the theoretical mechanism of the confinement crossover from the fractionalized Fermi liquid (FL*) phase to the stripy spin density wave (SDW) phase at low temperatures in hole-doped cuprates, accounting for the interplay between charge order from condensation of the SU(2) fundamental Higgs field B and the confinement of fermionic spinons mediated by the SU(2) gauge field.

Background

The paper proposes that the pseudogap metal is a fractionalized Fermi liquid (FL*) supported by a π-flux SU(2) spin liquid and introduces an SU(2) fundamental Higgs field B (distinct from the Higgs field Φ driving the FL–FL* transition). In this framework, low-temperature symmetry-broken phases such as d-wave superconductivity and charge order arise via condensation of B.

While several spectral and transport features are consistent with this approach, the specific pathway by which the system transitions from FL* to the stripy SDW state remains unresolved. The author highlights that understanding this crossover requires integrating the effects of charge order (from B condensation) and confinement of spinons via the SU(2) gauge field, suggesting numerical studies as a route to progress.