Quantized Nonlinear Pumping with Photons

The topological properties of the two dimensional integer quantum Hall effect are also captured by 1+1 dimensional pumping models. These, so called Thouless pumps [1], have served as simplified models to understand quantized transport. Exact quantization arises from uniform occupation of topologically nontrivial bands and can be observed in fermionic as well as bosonic systems. Here, we theoretically propose and experimentally observe quantized nonlinear Thouless pumping, with a decidedly nonuniform occupation of any band, in an array of weakly coupled waveguides with Kerr nonlinearity, which arises due to the ambient borosilicate glass.