Main Page | See live article | Alphabetical index In physics, the Schwinger model is the model describing 2D Euclidean quantum electrodynamics with a Dirac fermion. This model exhibits a spontaneous symmetry breaking of the U(1) symmetry due to a chiral condensate. The photon now becomes a massive particle. This model can be solved exactly and is used as a toy model for other more complicated theories. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.