The tricritical point of finite-temperature phase transitions in large N(Higgs) gauge theories

الأصل · EN

Gauge theories broken by a single Higgs field are known to have first-order phase transitions in temperature if λ/g² ≪ 1, where g is the gauge coupling and λ the Higgs self-coupling. If the theory is extended from one to N Higgs doublets, with U(N) flavor symmetry, the transition is known to be second order for λ/g² 1 in the N→∞ limit. We show that one can in principal compute the tricritical value of λ/g², separating first from second-order transitions, to any order in 1/N. In particular, scalar fluctuations at the transition damp away the usual problems with the infrared behavior of high-temperature non-Abelian gauge theories. We explicitly compute the tricritical value of λ/g² for U(1) and SU(2) gauge theory to next-to-leading order in 1/N.