Signatures of Domain-Wall Confinement in Raman Spectroscopy of Ising Spin Chains

Mesonic bound states of domain walls can be stabilized in quasi one-dimensional magnetic compounds. Here, we theoretically study the Raman light scattering response of a twisted Kitaev chain with tilted magnetic fields as a minimal model for confinement in ${\mathrm{C}\mathrm{o}\mathrm{N}\mathrm{b}}_2{\mathrm{O}}_6$. By both numerical matrix product states and few-domain wall variational states, we show that confinement-induced bound states directly manifest themselves as sharp peaks in the Raman response. Remarkably, by tuning the polarization of the incident light field, we demonstrate that the Raman response offers new insights into the intrinsic symmetry of the bound state wavefunction.