Quantum Simulation of Two-Dimensional Coherent Spectra for High-Spin Models

Terahertz two-dimensional coherent spectroscopy (2DCS) is a powerful technique for probing low-energy spin excitations in magnetic quantum materials, providing insights often inaccessible through other methods. We employ the adaptive variational quantum dynamics simulation (AVQDS) approach to efficiently compute 2DCS spectra of high-spin models, addressing challenges posed by high dimensionality and entanglement in these systems. We focus on an antiferromagnetic quantum spin model characterized by Dzyaloshinskii-Moriya interaction and single-ion anisotropy. Our statevector simulations show that AVQDS accurately captures spin dynamics driven by magnetic field pulses, yielding high-resolution frequency spectra. We further explore quantum resource scaling with spin magnitude and system size, comparing standard binary and Gray encodings. Our results indicate comparable resource requirements at low fields, with Gray code offering an advantage under strong driving. Simulated 2DCS spectra align well with experimental data from a rare-earth orthoferrite, emphasizing the need of quantum models for accurately capturing the observed high-harmonic generation signals.