Effects of topology on the light front

We discuss how to construct theta vacua in the light-front field theories u sing the 1+1 dimensional Abelian Higgs model as an example. Unlike the non- gauged scalar field, zero modes of the Higgs field are in general dynamical as well as the gauge-held zero mode. While symmetry breaking is discussed in semi-classical treatment of the zero modes, the theta vacua are introduc ed in the quantum level by use of the large gauge symmetry.