Experimental Quantum Seminar - Nicholas Laurita, California Institute Of Technology, “Shining Light On Quantum Materials”

“Shining Light On Quantum Materials”
Despite the undeniably quantum nature of interactions in solids at the microscopic scale, macroscopic measurements of material properties nearly always give classical results. This is in contrast to so-called “quantum materials,” in which non-trivial topology or high levels of entanglement drive the emergence of demonstrably macroscopic quantum phenomena. A prototypical example of such quantum matter is highly frustrated magnetic insulators, which recent theoretical analyses have suggested may possess exotic fractionalized quasi-particles that are beneficial for quantum computation. However, despite intense interest in recent years, a microscopic understanding of these materials is lacking due to the many-body nature of spin-Hamiltonians as well as the hindrance of typical techniques for probing dynamic magnetic responses. In this talk, I will demonstrate how a suite linear and non-linear ultrafast optical techniques are uniquely suited to probe and control strongly correlated quantum matter. First, I will demonstrate how the low-energy linear response of FeSc2S4 naturally encodes signatures of a unique long-ranged entangled “spin-orbital liquid” ground state that is on the edge of quantum criticality. Then, I will detail how non-linear optical techniques can exploit the intimate relationship between symmetry and ground state to uncover a hidden nematicity in the prototypical Kagome spin-liquid candidate Herbertsmithite ZnCu3(OH)6Cl2. Together, these results embody the unique promise that optical techniques hold in the emerging quantum materials research forefront.
Host: Bonnie Fleming