Regensburg 2022 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 23: Frustrated Magnets - General
TT 23.3: Talk
Wednesday, September 7, 2022, 15:30–15:45, H22
Fractionalized quantum criticality in spin-orbital liquids from field theory beyond the leading order — Shouryya Ray1, Bernhard Ihrig2, •Daniel Kruti3, John A. Gracey4, Michael M. Scherer2, and Lukas Janssen1 — 1TU Dresden — 2University of Cologne — 3University of Cologne and Jülich Research Centre — 4University of Liverpool
Two-dimensional spin-orbital magnets with strong exchange frustration have recently been predicted to realise 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 characterise the quantum critical behaviour 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 ν, the order-parameter anomalous dimension ηφ, and the fermion anomalous dimension ηψ using a three-loop 4-є expansion, a second-order large-N expansion (with the fermion anomalous dimension obtained even at the third order), as well as a functional renormalisation group approach. The results from the different methods agree well with each other and provide a prime benchmark for future complementary calculations. Averaging over them, we obtain the estimates 1/ν=1.03(15), ηφ=0.42(7), and ηψ=0.180(10) for the physically relevant case of N=3 flavours of two-component Dirac fermions in 2+1 space-time dimensions.