Theta vacuum of the bosonized massive light-front Schwinger model

The massive Schwinger model in bosonic representation is quantized on the light front using the Dirac–Bergmann method and focusing on vacuum aspects. The non-perturbative theta vacuum in terms of coherent states of the gauge-field zero mode is derived and found to coincide with the simple, but non-trivial vacuum of the massless model. On the other hand, the mass term becomes complicated due to the constrained zero mode of the scalar field, and can only be treated iteratively. As an example, the theta dependence of the leading order mass correction to the chiral condensate is calculated.