Condensed Matter/Materials & Biological Physics Seminar with Pontus Laurell on Witnessing quantum correlations and entanglement in materials

Entanglement and other nonclassical correlations are ubiquitous in quantum many-body systems. This is well-established in quantum information applications, where they represent resources to be harnessed for quantum operations. However, they also play a prominent role in theories of important condensed matter phenomena, such as novel phases of matter. Yet there has been a distinct lack of viable methods to detect these correlations in the solid state, impeding our ability to identify suitable materials and to unravel their secrets. In this talk I will describe progress towards finding useful measures of these properties, which can both be modeled theoretically and measured experimentally in a model-independent fashion, by making use of information "hidden" in spectroscopic data. By employing entanglement witnesses---quantities akin to order parameters for certain classes of entangled states---multipartite entanglement has now been observed in quantum spin systems, and recently also strongly correlated electron systems. Such quantum information-informed approaches offer new quantitative insights into many-body states, and can provide hints for modeling of enigmatic states in quantum materials.

This lecture was made possible by the William C. Ferguson Fund.