Exactly Solved Model of Self-Organized Criticality

We introduce and solve an anisotropic model of self-organized criticality. The exponents are $\tau =4\mathrm{}/3$, $D=3\mathrm{}/2$, $\nu =2\mathrm{}$, $d_f=1\mathrm{}/2$, $z=1\mathrm{}$, and $\theta =1\mathrm{}$. This model is related to one-dimensional anisotropic interface depinning in a quenched random medium. Another anisotropic interface model, different from the first one in the realization of quenched disorder, is shown numerically to belong to the same universality class as the first one.