Dissipative Abelian Sandpile Models

We introduce a family of abelian sandpile models with two parameters $n, m \in {\bf N}$ defined on finite lattices on $d$-dimensional torus. Sites with $2dn+m$ or more grains of sand are unstable and topple, and in each toppling $m$ grains dissipate from the system. Because of dissipation in bulk, the models are well-defined on the shift-invariant lattices and the infinite-volume limit of systems can be taken. From the determinantal expressions, we obtain the asymptotic forms of the avalanche propagators and the height-$(0,0)$ correlations of sandpiles for large distances in the infinite-volume limit in any dimensions $d \geq 2$. We show that both of them decay exponentially with the correlation length $ξ(d, a)=(\sqrt{d} \sinh^{-1} \sqrt{a(a+2)} \ )^{-1},$ if the dissipation rate $a =m/(2dn)$ is positive. By considering a series of models with increasing $n$, we discuss the limit $a \downarrow 0$ and the critical exponent defined by $ν_{a}=- \lim_{a \downarrow 0} \log ξ(d, a)/ \log a$ is determined as $ν_{a}=1/2$ for all $d \geq 2$. Comparison with the $q \downarrow 0$ limit of $q$-state Potts model in external magnetic field is discussed.

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