Possible Observation of fractionalized excitations in a Relativistic Mott Insulator

The combination of electronic correlation and spin-orbit coupling is thought to precipitate a variety of highly unusual electronic phases in solids, including topological and quantum spin liquid states. I will discuss our recent optical measurements that provide evidence for the relativistic Mott Insulating ground state of $\alpha$-RuCl$_{3}$. Furthermore I will discuss the broad-continuum of scattering we observe, whose energy and temperature dependence suggest the presence of fractionalized excitations emerging from a quantum spin-liquid.