Two-dimensional coherent spectrum of interacting spinons from matrix product states

We compute numerically the second-and third-order nonlinear magnetic susceptibilities of an Ising ladder model in the context of two-dimensional coherent spectroscopy by using the infinite time-evolving block decima-tion method. The Ising ladder model couples a quantum Ising chain to a bath of polarized spins, thereby effecting the decay of spinon excitations. We show that its third-order susceptibility contains a robust spinon echo signal in the weak-coupling regime, which appears in the two-dimensional coherent spectrum as a highly anisotropic peak on the frequency plane. The spinon echo peak reveals the dynamical properties of the spinons. In particular, the spectral peak corresponding to the high-energy spinons, which couple to the bath, is suppressed with increasing coupling, whereas those corresponding to low-energy spinons do not show any significant changes.

Automated summary

We numerically compute the second and third-order nonlinear magnetic susceptibilities of an Ising ladder model in the context of two-dimensional coherent spectroscopy using the infinite time-evolving block decimation method. The third-order susceptibility of the model exhibits a robust spinon echo signal in the weak-coupling regime, appearing as a highly anisotropic peak on the frequency plane in the two-dimensional coherent spectrum. This spinon echo peak provides insight into the dynamical properties of the spinons, with the spectral peak corresponding to high-energy spinons suppressed with increasing coupling, while those corresponding to low-energy spinons show no significant changes.