We propose a qubit basis composed of transverse spin helices with kinks. Unlike the usual computational basis, this chiral basis is well suited for describing quantum states with nontrivial topology. Choosing appropriate parameters the operators of the transverse spin components, $\sigma_n^x$ and $\sigma_n^y$, become diagonal in the chiral basis, which facilitates the study of problems focused on transverse spin components. As an application, we study the temporal decay of the transverse polarization of a spin helix in the XX model that has been measured in recent cold atom experiments. We obtain an explicit universal function describing the relaxation of helices of arbitrary wavelength.
Comment: 5 pages, 2 figures; v2: major revision and new material, title changed and an author added; v3: revised version, accepted for publication by Phys. Rev. Lett., title changed again, references added, supplemental material appended