Spontaneous symmetry breaking of SO(2N) in Gross-Neveu theory from 2+ε expansion
(i)--(iii). Before becoming equal to the Gaussian fixed point at Nf=1 , (ii) remains critical for all values of Nf>NSTf ,c (N )≈0.56+1. 48N+ (ϵ) , which compares well with the estimate of previous studies [...] fermions. Mean-field theory for the SO( 2N ) model predicts, besides the chiral Ising transition at gc1 , a second critical point gc2 where SO( 2N ) is broken down to SO (N )×SO (N ). A subsequent Wilsonian [...] point separately. However, it turns out that (ii) and (iii) lose their criticality when approaching Nf=1 , suggesting that the transition is first order. In this work, we approach the problem from the low …
