Theoretical Physics Seminar: Giandomenico Palumbo (Brussels)

Revealing tensor monopoles through the quantum metric in ultracold atoms

Monopoles are intriguing topological objects, which play a central role
in gauge theories and topological states of matter. While conventional
monopoles are found in odd-dimensional flat spaces, such as the Dirac
monopole in three dimensions and the non-Abelian Yang monopole in five
dimensions, more exotic objects were predicted to exist in even
dimensions. This is the case of “tensor monopoles”, which are associated
with generalized (tensor) gauge fields, and which can be defined in four
dimensional flat spaces. In this work, we investigate the possibility of
creating and measuring such a tensor monopole, by introducing a
realistic three-band model defined over a four-dimensional parameter
space. Our probing method is based on the observation that the
topological charge of this tensor monopole, which we relate to a
generalized Berry curvature, can be directly extracted from the quantum
metric. We propose a realistic three-level atomic system, where tensor
monopoles could be generated and revealed through quantum-metric
measurements.