Recent analytical work has shown that, at certain values of the external
pump, the optical parametric oscillator (OPO) regime of microcavity polaritons
may provide a realisation of Kardar-Parisi-Zhang (KPZ) physics in 2D. Here, we
verify this by solving the full microscopic model numerically using the
truncated Wigner method, and studying the first order spatial correlations. For
the predicted pump strengths, these correlations decay much faster and,
perpendicular to the pump, fit closely to the stretched exponential form
predicted by the KPZ equation, in contrast to the usual algebraic decay. This
strongly indicates the viability of observing KPZ behaviour in future polariton
OPO experiments.Comment: Main text (6 pages, 5 figures) plus supplementary material (3 pages,
5 figures
