Marginal Ginzburg criterion
= Marginal Ginzburg criterion
At an <upper critical dimension>, the leading <Ginzburg criterion> ratio has zero thermal power rather than a negative one. It does not vanish asymptotically, but its magnitude can depend on the coupling. The criterion alone does not establish a power-law divergence or new critical power exponents. Running marginal interactions generally produce logarithmic corrections; the ordinary quartic and tricritical sextic scalar theories are examples.