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SUMMARY:Anton Kapustin (Caltech)
DTSTART:20210427T150000Z
DTEND:20210427T160000Z
DTSTAMP:20260422T212925Z
UID:IHES-Quantum-Encounters/1
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/IHES-Quantum
 -Encounters/1/">Noncommutative geometry of quantum lattice models and the 
 higher Berry phase</a>\nby Anton Kapustin (Caltech) as part of IHES Quantu
 m Encounters\n\n\nAbstract\nRecently methods of quantum statistical mechan
 ics have been fruitfully applied to the study of phases of quantum lattice
  systems at zero temperature. For example\, a rigorous definition of a Sho
 rt-Range Entangled phase of matter has been given and a classification of 
 such phases in one spatial dimension has been achieved. I will discuss som
 e of these developments\, focusing on the topology and geometry of the spa
 ce of Short-Range Entangled states. According to a conjecture of A. Kitaev
 \, these spaces form a loop spectrum in the sense of homotopy theory. This
  conjecture implies that to any family of Short-Range entangled states in 
 one dimension one can associate a gerbe on the parameter space. I will sho
 w how to construct such a gerbe. Thе curvature of this gerbe is a closed 
 3-form with quantized periods and can be regarded as a higher-dimensional 
 generalization of the curvature of the Berry connection.\n\nSee seminar we
 bpage https://seminars.ihes.fr/quantum/ for the zoom link\n
LOCATION:https://researchseminars.org/talk/IHES-Quantum-Encounters/1/
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SUMMARY:Peter C.W. Holdsworth (Ecole Normale Supérieure de Lyon)
DTSTART:20210601T140000Z
DTEND:20210601T150000Z
DTSTAMP:20260422T212925Z
UID:IHES-Quantum-Encounters/2
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/IHES-Quantum
 -Encounters/2/">Emergence: from spins to charges</a>\nby Peter C.W. Holdsw
 orth (Ecole Normale Supérieure de Lyon) as part of IHES Quantum Encounter
 s\n\n\nAbstract\nEmergence is a major buzz word of our times. My working d
 efinition\, which gives plenty of room for manoeuvre is: the appearance of
  many body phenomena of higher symmetry than that of the Hamiltonian and d
 egrees of freedom at the microscopic level.\n\nIn this colloquium I will d
 iscuss a topical example - the frustrated magnetic material\, spin ice. He
 re\, to an excellent approximation a classical field theoretic description
  with continuous U(1) symmetry emerges from Ising like degrees of freedom.
  The associated quasi-particles appear to be freely moving magnetic charge
  - magnetic monopoles - and the system behaves as a magnetic Coulomb fluid
  in the grand canonical ensemble with intrinsic topological properties. Wi
 th the addition of quantum fluctuations the emergent magneto-statics devel
 ops further into a complete analogue of quantum electrodynamics. I will al
 iment this discussion with experimental results from a wide range of syste
 ms.\n\nSee the zoom link at https://indico.math.cnrs.fr/event/6687/\n
LOCATION:https://researchseminars.org/talk/IHES-Quantum-Encounters/2/
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