Gradient-flowed order parameter for spontaneous gauge symmetry breaking
Kengo Kikuchi (RIKEN iTHEMS, Wako, Saitama, 351-0198, Japan); Kenji Nishiwaki (Department of Physics, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, 201314, India); Kin-ya Oda (Department of Mathematics, Tokyo Woman’s Christian University, Tokyo, 167-8585, Japan)
The gauge-invariant two-point function of the Higgs field at the same spacetime point can make a natural gauge-invariant order parameter for spontaneous gauge symmetry breaking. However, this composite operator is ultraviolet divergent and is not well defined. We propose using a gradient flow to cure the divergence from putting the fields at the same spacetime point. As a first step, we compute it for the Abelian Higgs model with a positive mass squared at the one-loop order in the continuum theory using the saddle-point method to estimate the finite part. The order parameter consistently goes to zero in the infrared limit of the infinite flow time.