Fractionalized quantum criticality in spin-orbital liquids from field theory beyond the leading order

Two-dimensional spin-orbital magnets with strong exchange frustration have recently been predicted to facilitate the realization of a quantum critical point in the Gross-Neveu-SO(3) universality class. In contrast to previously known Gross-Neveu-type universality classes, this quantum critical point separates a Dirac semimetal and a long-range-ordered phase, in which the fermion spectrum is only partially gapped out. Here, we characterize the quantum critical behavior of the Gross-Neveu-SO(3) universality class by employing three complementary field-theoretical techniques beyond their leading orders. We compute the correlation-length exponent nu, the order-parameter anomalous dimension eta(phi), and the fermion anomalous dimension eta(psi) using a three-loop epsilon expansion around the upper critical space-time dimension of four, a second-order large-N expansion (with the fermion anomalous dimension obtained even at the third order), as well as a functional renormalization group approach in the improved local potential approximation. For the physically relevant case of N = 3 flavors of two-component Dirac fermions in 2 + 1 space-time dimensions, we obtain the estimates 1/nu = 1.03(15), eta(phi) = 0.42(7), and eta(psi) = 0.180(10) from averaging over the results of the different techniques, with the displayed uncertainty representing the degree of consistency among the three methods.

Automated summary

This study characterizes the quantum critical behavior of the Gross-Neveu-SO(3) universality class using three complementary field-theoretical techniques, and obtains estimates for the correlation-length exponent, order-parameter anomalous dimension, and fermion anomalous dimension. The results are obtained by averaging over different techniques and the uncertainty displayed represents the degree of consistency among the methods.