Speaker: Pontus Laurell (U of Tennessee)
Host: Rebecca Flint

Title: Witnessing quantum correlations and entanglement in materials

Abstract: 
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 strongly correlated electron systems are around the corner. 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.

Brief bio:
Dr. Pontus Laurell is currently a postdoc in theoretical condensed matter physics at the University of Tennessee, Knoxville. He has a bachelor's degree in engineering physics and a master's degree in fundamental physics from Chalmers University of Technology, in Gothenburg, Sweden. He received his PhD in 2018 from the University of Texas at Austin with Prof. Gregory Fiete. From graduation until 2021, he was a postdoc at Oak Ridge National Laboratory, where he developed strong collaborations with quantum magnetism experimentalists, and a deep interest in applications of quantum information methods to quantum materials.