  A permutation graph is a graph whose edges are given by inversions of a
permutation. We study the Abelian sandpile model (ASM) on such graphs. We
exhibit a bijection between recurrent configurations of the ASM on permutation
graphs and the tiered trees introduced by Dugan et al. [10]. This bijection
allows certain parameters of the recurrent configurations to be read on the
corresponding tree. In particular, we show that the level of a recurrent
configuration can be interpreted as the external activity of the corresponding
tree, so that the bijection exhibited provides a new proof of a famous result
linking the level polynomial of the ASM to the ubiquitous Tutte polynomial. We
show that the set of minimal recurrent configurations is in bijection with the
set of complete non-ambiguous binary trees introduced by Aval et al. [2], and
introduce a multi-rooted generalization of these that we show to correspond to
all recurrent configurations. In the case of permutations with a single
descent, we recover some results from the case of Ferrers graphs presented in
[11], while we also recover results of Perkinson et al. [16] in the case of
threshold graphs.
