Monopole Quantum Numbers in the Staggered Flux Spin Liquid

TL;DR

This paper investigates the quantum numbers of monopole operators in the staggered-flux spin liquid, revealing their connection to various symmetry-breaking orders and identifying a monopole with trivial quantum numbers, relevant to high-T_c pseudogap physics.

Contribution

It provides the first detailed analysis of monopole quantum numbers in the staggered-flux spin liquid, linking them to known and novel symmetry-breaking phases.

Findings

Monopole operators encode Neel and valence bond solid orders.

One monopole operator carries trivial quantum numbers.

Results have implications for high-T_c pseudogap phenomena.

Abstract

Algebraic spin liquids, which are exotic gapless spin states preserving all microscopic symmetries, have been widely studied due to potential realizations in frustrated quantum magnets and the cuprates. At low energies, such putative phases are described by quantum electrodynamics in 2+1 dimensions. While significant progress has been made in understanding this nontrivial interacting field theory and the associated spin physics, one important issue which has proved elusive is the quantum numbers carried by so-called monopole operators. Here we address this issue in the ``staggered-flux'' spin liquid which may be relevant to the pseudogap regime in high-T_c. Employing general analytical arguments supported by simple numerics, we argue that proximate phases encoded in the monopole operators include the familiar Neel and valence bond solid orders, as well as other symmetry-breaking orders closely related to those previously explored in the monopole-free sector of the theory. Surprisingly, we also find that one monopole operator carries trivial quantum numbers, and briefly discuss its possible implications.