Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The effect of quenched disorder in neutral theories   We study systems with two symmetric absorbing states, such as the voter model
and variations of it, which have been broadly used as minimal neutral models in
genetics, population ecology, sociology, etc. We analyze the effects of a key
ingredient ineluctably present in most real applications: random-field-like
quenched disorder. In accord with simulations and previous findings,
coexistence between the two competing states/opinions turns out to be strongly
favored by disorder in the standard voter model; actually, a disorder-induced
phase transition is generated for any finite system size in the presence of an
arbitrary small spontaneous-inversion rate (preventing absorbing states from
being stable). For non-linear versions of the voter model a general theory (by
AlHammal et al.) explains that the spontaneous breaking of the up/down symmetry
and an absorbing state phase transition can occur either together or
separately, giving raise to two different scenarios. Here, we show that he
presence of quenched disorder in non-linear voter models does not allow the
separation of the up-down (Ising-like) symmetry breaking from the
active-to-absorbing phase transition in low-dimensional systems: both phenomena
can occur only simultaneously, as a consequence of the well-known Imry-Ma
argument generalized to these non-equilibrium problems. When the two phenomena
occur at unison, resulting into a genuinely non-equilibrium ("Generalized
Voter") transition, the Imry-Ma argument is violated and the symmetry can be
spontaneously broken even in low dimensions.

26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph