Density Dependent Gauge Field Inducing Emergent Su-Schrieffer-Heeger Physics, Solitons, and Condensates in a Discrete Nonlinear Schrödinger Equation.

We investigate a discrete nonlinear Schrödinger equation with dynamical, density-difference-dependent gauge fields. We find a ground-state transition from a plane wave condensate to a localized soliton state as the gauge coupling is varied. Interestingly we find a regime in which the condensate and soliton are both stable. We identify an emergent chiral symmetry, which leads to the existence of a symmetry-protected zero-energy edge mode. The emergent chiral symmetry relates low and high energy solitons. These states indicate that the interaction acts both repulsively and attractively.