The critical properties of the QED3 Gross-Neveu-Yukawa (GNY) model in 2+1 dimensions with N flavors of two-component Dirac fermions are computed to first order in the 1/N expansion. For the specific case of N = 2, the critical point is conjectured to be dual to the Néel-to-valence-bond-solid (VBS) deconfined critical point of quantum antiferromagnets on the square lattice. It is found that Aslamazov-Larkin diagrams, missed by previous -and 1/N -expansion studies with four-component fermions, give important contributions to the scaling dimensions of various operators. With the inclusion of these diagrams, the resummed scaling dimensions of the adjoint fermion bilinear and scalar field at the QED3 GNY critical point are in reasonable agreement with numerical studies of the Néel-to-VBS transition, in support of the duality conjecture. arXiv:1812.02720v2 [cond-mat.str-el]

We present a field theory description of a quantum phase transition in two spatial dimensions between a U (1) algebraic spin liquid with N flavors of gapless two-component Dirac fermionic spinons and a gapped Z2 spin liquid. This transition is driven by spinon pairing and concomitant Higgsing of the emergent U (1) gauge field. For sufficiently large N we find a quantum critical point with non-Gaussian exponents that is stable against instanton proliferation. We compute critical exponents using either 1/N or expansions, and give estimates of the critical value of N below which the quantum critical point disappears.arXiv:1804.00054v2 [cond-mat.str-el]

Abstract:We study the role of the lattice artifacts associated with the Coulomb binding effects in the analysis of the heavy quarkonium within lattice NRQCD. We find that a "naïve" perturbative matching generates spurious linear Coulomb artifacts, which result in a large systematic error in the lattice predictions for the heavy quarkonium spectrum. This effect is responsible, in particular, for the discrepancy between the recent determinations of the bottomonium hyperfine splitting in the radiatively improved lattice NRQCD [1,2]. We show that the correct matching procedure which provides full control over discretization errors is based on the asymptotic expansion of the lattice theory about the continuum limit, which gives M Υ(1S) − M η b (1S) = 52.9 ± 5.5 MeV [1].

We derive the extended Supersymmetric Galilean Conformal Algebra (SGCA) in two spacetime dimensions by the method of group contraction on 2d N = (2, 2) superconformal algebra. Both the parent and daughter algebras are infinite-dimensional. We provide the representation theory of the algebra. We adopt a superspace formalism for the SGCA fields, allowing us to write them down in a compact notation as components of superfields. We also discuss correlation functions, short supermultiplets and null states. arXiv:1601.04723v2 [hep-th]

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