Is the Manna class distinct from directed percolation
In plain words
Sandpile-like models in which grains are conserved show absorbing transitions that some argue form their own universality class, the Manna class. Others argue the differences are slow transients, or that the class coincides with the pinning of an elastic interface in a random medium.
Precise statement
For the Manna model and conserved lattice gases (fixed-energy sandpiles) in $d = 1, 2, 3$, determine whether the absorbing transition belongs to a class distinct from DP, and whether it coincides with depinning of a disordered elastic interface (quenched Edwards-Wilkinson class) as field-theory mappings suggest. An answer is a classification with exponent values in each $d$.
What would settle it
Simulations on large systems with control of the long transients, showing which exponent set the Manna model converges to, consistent with a field-theory mapping.
Status in the literature
Unverified note
Claims of generic DP behavior (arXiv:1206.3121, 2012) are disputed; a 2024 study uses the mapping to depinning to predict hyperuniformity in this class (arXiv:2401.09123).