A synthetic monopole source of Kalb-Ramond field in diamond

Magnetic monopoles play a central role in areas of physics that range from electromagnetism to topological matter. String theory promotes conventional vector gauge fields of electrodynamics to tensor gauge fields and predicts the existence of more exotic tensor monopoles. Here, we report the synthesis of a tensor monopole in a four-dimensional parameter space defined by the spin degrees of freedom of a single solid-state defect in diamond. Using two complementary methods, we characterized the tensor monopole by measuring its quantized topological charge and its emanating Kalb-Ramond field. By introducing a fictitious external field that breaks chiral symmetry, we further observed an intriguing spectral transition, characterized by spectral rings protected by mirror symmetries. Our work demonstrates the possibility of emulating exotic topological structures inspired by string theory.

Automated summary

This study reports the synthesis of a tensor monopole in a single solid-state defect in diamond, characterizing its properties through quantized topological charge and Kalb-Ramond field measurements. Introducing an external field that breaks chiral symmetry led to an intriguing spectral transition with spectral rings protected by mirror symmetries. The work demonstrates the possibility of emulating exotic topological structures inspired by string theory.