From G2 to SO(8): Emergence and reminiscence of supersymmetry and triality
摘要
We construct a (1+1)-dimension continuum model of 4-component fermions incorporating the exceptional Lie group symmetry G2. Four gapped and five gapless phases are identified via the one-loop renormalization group analysis. The gapped phases are controlled by four different stable SO(8) Gross-Neveu fixed points, among which three exhibit an emergent triality, while the rest one possesses the self-triality, i.e., invariant under the triality mapping. The gapless phases include three SO(7) critical ones, a G2 critical one, and a Luttinger liquid. Three SO(7) critical phases correspond to different SO(7) Gross-Neveu fixed points connected by the triality relation similar to the gapped SO(8) case. The G2 critical phase is controlled by an unstable fixed point described by a direct product of the Ising and tricritical Ising conformal field theories with the central charges c =