[Seminar] Witnessing entanglement in magnets using neutrons

Speaker

Dr. Alan Tennant / Oak Ridge National Laboratory

Distinguished Scientist, Labwide Quantum Materials Initiative lead, project lead in the Quantum Science Center for Topological Quantum Information, and Director of the Shull Wollan Institute. My research is primarily undertaken with neutron and xray scattering techniques on condensed matter systems, as well as complementary theoretical and computational studies. The main topics covered are: Fractionalization of quantum numbers which can in principle occur in low dimensional or highly frustrated quantum magnets; physics at high magnetic fields and millikelvin temperatures; quantum magnetism and quantum phase transitions; and electronic states with strong correlations. Currently I am working on quantum glass formation; the application of topological concepts to materials including Weyl semimetals and spin liquids; topologically protected quantum states; correlation in disordered matter; fundamentals of transport theory; and the application of machine learning to scattering problems and magnetic simulations.

Title

Witnessing entanglement in magnets using neutrons

Abstract

In the absence of detailed theories, identifying quantum states in materials is a formidable task. Quantum information theory provides frameworks and protocols to witness entanglement in interacting quantum systems such as qubits and cold atoms. These often involve combinations of correlation functions.  Scattering techniques in condensed matter provide access to such correlations in materials and so the question arises can these be used to provide model agnostic measures of quantum entanglement and allow more direct conclusions on the quantum phases to be drawn from experiment?  I provide examples of how we can measure total entanglement, entanglement between pairs of spins, and the entanglement depth using one tangle, two tangle, and quantum Fisher information extracted from neutron scattering data. I consider examples of measurements of quantum magnets and how they can be interpreted including for quantum phase transitions and spin liquids.

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ID: 984 1301 6935
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