Doped planar quantum antiferromagnets with striped phases

We study the properties of the striped phases that have been proposed for the doped cuprate planar quantum antiferromagnets. We invoke an effective, spatially anisotropic, non-linear sigma model in two space dimensions. Our theoretical predictions are in {\it quantitative} agreement with recent experiments. We focus on (i) the staggered magnetization at $T=0$ and (ii) the N\'eel temperature, as functions of doping; these have been measured recently in La${}_{2-x}$ Sr${}_x$ Cu O${}_4$ with $0 \leq x \leq 0.018$. Good agreement with experiment is obtained using parameters determined previously and independently for this system. These results support the proposal that the low doping (antiferromagnetic) phase of the cuprates has a striped configuration.