Xiao Ma, University of Cambridge

Hyperuniformity at the Absorbing State Transition

Hyperuniform systems, whereby the static structure factor (or density correlator) obeys S(q)~q^h with h > 0, emerges at criticality in systems having multiple absorbing states, such as periodically sheared suspensions. These lie in the conserved directed percolation (C-DP) universality class, for which analytic results for h are lacking. Here, using Doi-Peliti field theory for interacting particle systems and performing perturbative renormalization group about a Gaussian model, we find h=0+ and h=2ε/9+O(ε^2) in dimension d > 4 and d = 4−ε respectively. We show how hyperuniformity emerges from anticorrelation of strongly fluctuating active and passive densities, and highlight the significance of an ‘irrelevant’ conserved noise.