Abstract

Non-reciprocal interactions between scalar fields that represent the concentrations of two active species are known to break the parity and time-reversal (PT) symmetries of the equilibrium state, as manifested in the emergence of travelling waves. In my talk I will discuss various aspects of the Non-reciprocal Cahn-Hilliard model. I will discuss the role of an active pressure in determining the dynamical steady state. I will explore the notion of nonlinear non-reciprocity and consider a model in which the non-reciprocal interactions can depend on the local values of the scalar fields. For generic cases where such couplings exist, we observe the emergence of spatiotemporal chaos in the steady-state associated with a local restoration of PT symmetry in fluctuating spatial domains, which leads to the coexistence of oscillating densities and phase-separated droplets that are spontaneously created and annihilated. Finally I will discuss the role of fluctuations in the ordered ‘polar state’ that arises in the system.