Seminar "The dynamics of a quantum spin liquid", John Chalker, University of Oxford

Theory of Quantum Matter unit would like to invite you to a seminar:

• Title: The dynamics of a quantum spin liquid
• Sepeaker: John Chalker, Professor at Physics Department, University of Oxford
• Date: Thursday, October 1st
• Time: 2:00-3:00pm
• Venue: C016, Lab 1

The dynamics of a quantum spin liquid

John Chalker
(Physics Department, Oxford University)

Spin liquids have been viewed as a possible phase of matter since P. W. Anderson's work on resonating valence bonds some forty years ago. There has been enormous progress in the intervening years, and we now have good candidate materials, in the form of both organic molecular magnets and insulating transition metal compounds, as well as a greatly improved theoretical understanding of spin liquids states. I will give a brief overview of the status of this field and will also outline recent theoretical results on the dynamics of a remarkably simple, exactly solvable model (the Kitaev honeycomb model) that has a spin liquid ground state. In this system, magnetic moments are “dissolved" by quantum fluctuations and reform as new degrees of freedom: mobile fermions and flux lines of an emergent gauge field. I will discuss the implications of this reorganisation, known as quantum number fractionalisation, for measurements of dynamics such as the inelastic neutron scattering response.

Biography of John Chalker

John Chalker is a Professor in the Physics Department at Oxford University, and one of the leading condensed-matter theorists of his generation. He is especially known for the eponymous Chalker-Coddington network model which accounts for the main features of the quantum Hall transitions, and more generally for his pioneering work in exotic quantum phenomena.  He was the Institute of Physics Mott Lecturer in 2000 and was awarded the Rayleigh Medal and Prize of the Institute of Physics in 2008. It is his first visit to Japan.