Simulating nuclear magnetic resonance (NMR) signals of axion-like particles (ALPs)

The search for dark matter is one of the central challenges of modern physics, yet an unambiguous detection remains elusive. While conventional searches have constrained broad regions of parameter space, alternative approaches with enhanced sensitivity to weak, small-scale signals are becoming increasingly important. One promising method is to directly probe axion-like particles (ALPs) using pulsed nuclear magnetic resonance (NMR), where the ALP’s oscillating effective magnetic field induces a torque on nuclear spins. In this work, we employ PULSEE (Program for the Simulation of Nuclear Spin Ensemble Evolution), an open-source Python library developed by our group, to model NMR experiments that include interactions with external ALPs. The simulated signals exhibit distinct observables corresponding to the ALP's properties that are consistent with analytical predictions. Based on these results, we propose that NMR experiments in low-temperature superfluids with nuclei of large gyromagnetic ratios can achieve exceptional sensitivity to external fields, offering a promising pathway toward detecting ALP dark matter.