IGOR HERBUT, Simon Fraser University
QUANTUM NUMBERS OF TOPOLOGICAL DEFECTS AND REAL CLIFFORD ALGEBRAS IN DIRAC SYSTEMS
Lunedì 21 Gennaio 2013, ore 17:00
Università di Milano, Dipartimento di Matematica |
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Abstract
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I will discuss the emergent Dirac quasiparticles in the lattice systems of electrons, exemplified by graphene, in the presence of topological defects of the allowed superconducting and insulating, order parameters. These orders appear as possible mass terms in the Dirac equation, and their topological defects have been known to carry non-trivial quantum numbers such as charge and spin since the work of Jackiw and Rebby in 1976.
In the talk I will discuss their additional internal degree of freedom: irrespectively of the nature of orders that support the defect, an extra
mass-order-parameter spontaneously emerges in the defect's core. The determination of the quantum state of the topological defect turns out to be an interesting problem in the representation theory of (real) Clifford algebras; with the Clifford algebra C(2,5) playing a fundamental role in graphene, for example. Ultimately, the particle-hole symmetry restricts the defects to always carry the quantum numbers of a single effective isospin-1/2, quite independently of the values of their electric charge or true spin. Examples of this new degree of freedom in graphene and on surfaces of topological insulators will be given. |
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JAMES ROBINSON, Warwick University
INTERPOLATION AND LADYZHENSKAYA INEQUALITY IN A COUPLED ELLIPITIC-PARABOLIC PROBLEM
Martedì 27 Novembre 2012, ore 17:00
Politecnico di Milano, Dipartimento di Matematica | |
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STEFANO OLLA, Ceremade, Université Paris Dauphine
DALLA DINAMICA ALLA TERMODINAMICA: E' POSSIBILE UNA DEDUZIONE MATEMATICA PRECISA?
Lunedì 26 Novembre 2012, ore 15:00
Università di Milano, Dipartimento di Matematica, Via Saldini | |
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ENRICO VALDINOCI, Università di Milano
A FRACTIONAL FRAMEWORK FOR PERIMETERS AND PHASE TRANSITIONS
Lunedì 05 Novembre 2012, ore 17:00
Dipartimento di Matematica del Politecnico, Aula Consiglio | |
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THOMAS SPENCER, Institute for Advanced Study, Princeton
SYMMETRY, STATISTICAL MECHANICS AND RANDOM MATRICES
Lunedì 15 Ottobre 2012, ore 16:30
Università di Milano, Dipartimento di Matematica, Via Saldini | |
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WALTER NOLL, Carnegie Mellon University
PHYSICS AND MATHEMATICS WITHOUT COORDINATES
Giovedì 04 Ottobre 2012, ore 17:00
Politecnico di Milano, Dipartimento di Matematica, Sala del Consiglio VII piano | |
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