At the atomic level, the open electronic shell of an ion is characterized by a local charge density and a magnetization density, emerging from the spin and orbital degrees of freedom. These densities can be decomposed in atomic-scale multipoles representing the electric and magnetic degrees of freedom. This expansion not only characterizes the densities shape and symmetry, it also defines the quantum mechanical operators of these atomic-scale multipoles, similar to spin operators. It is frequently assumed that the lowest order of this expansion is sufficient to describe material properties. However, there is an increasing list of materials with strong spin-orbit coupling that exhibit multipolar orders. Furthermore, multipolar interactions can theoretically mediate superconductivity and play a role in the ground state selection of frustrated magnets. This motivates me to investigate the potentially unrecognized role of multipolar physics in strongly correlated electronic states such as spin liquids and superconductors. I am also starting research projects on the topic of odd-parity multipoles, a class of unconventional multipoles that give rise to emergent cross-correlated responses of potential interest to spintronics.

The quantum spin liquid state is an exceptional phase of matter that exhibits long-range entanglement of the magnetic degrees of freedom. It represents one of the rare examples of long-range entanglement of a many-body system, also named topological order, and can shed light on concepts relevant to quantum information and computing. The so-called frustrated magnets are candidate materials in the search of spin liquids. Indeed, magnetic frustration leads to degenerate ground states and strong magnetic fluctuations, hindering conventional magnetic order to the profit of spin liquid states. I am especially interested about the role of multipolar interactions in selecting which type of ground state is stabilized.