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VERSION:2.0
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X-WR-CALNAME:Physics Colloquium: “Unified theory of interacting Dirac fer
 mions in two dimensions  and the dark side of the Gross-Neveu model” 
X-WR-TIMEZONE:Eastern Time (US & Canada)
BEGIN:VEVENT
DTSTAMP:20260720T193427Z
UID:tag:localist.com\,2008:EventInstance_52454294411471
DTSTART:20260402T202500Z
DTEND:20260402T212500Z
DESCRIPTION:Gapless (or "massless") Dirac fermions appear as low-energy exc
 itations in many condensed matter systems of recent interest.  They are of
 ten weakly interacting\, as famously in graphene\, but at stronger interac
 tions they can also acquire a gap ("mass") and exhibit many ordered ground
  states by going through phase transitions at which gapless Dirac fermions
  play a crucial role. Prime example of this occurs in the Hubbard model on
  honeycomb lattice at half filling\, which suffers a "relativistic Mott tr
 ansition" from gapless semimetal  to gapped insulator\, believed to be obs
 erved recently in twisted multilayers. I will discuss the recent attempt o
 f unification of all order parameters for Dirac systems in two dimensions 
 based on large but somewhat hidden orthogonal symmetry of free Dirac fermi
 ons. Interestingly\, the unique interacting field theory that respects suc
 h an orthogonal symmetry turns out to be equivalent to the celebrated Gros
 s-Neveu model.  I will argue that\, in spite of recently turning 50\, this
  model still has a large\, unexplored\, and surprisingly interesting regio
 n of its coupling constant.  Recent analytical and numerical results relev
 ant to this "dark side" of the Gross-Neveu model will be presented.\n\nIgo
 r Herbut is a professor of theoretical physics at Simon Fraser University 
 in Burnaby\, British Columbia. After receiving his Ph.D. From the  Johns H
 opkins University in Baltimore\, he spent the next three years as a Killam
  postdoctoral fellow at the University of British Columbia. His interests 
 lay in field theories of condensed matter\, and include quantum phase tran
 sitions\, unconventional superconductivity\, and unusual physics of graphe
 ne and other topological semimetals in two and three dimensions. He is an 
 author of a graduate textbook on theory of phase transitions and critical 
 phenomena for the Cambridge University Press\, a Fellow of the American Ph
 ysical Society\, and a member of the editorial board of the Physical Revie
 w B. For his work on interacting Dirac systems he was awarded the Marko Ja
 ric Award for 2017\,  and the Dresden Physics Prize of the Max Planck Inst
 itute and the Technical University Dresden for 2025.
GEO:40.607061;-75.376445
LOCATION:Lewis Lab\, 316
SUMMARY:Physics Colloquium: “Unified theory of interacting Dirac fermions
  in two dimensions  and the dark side of the Gross-Neveu model” 
URL;VALUE=URI:https://eventscalendar.lehigh.edu/event/physics-colloquium-un
 ified-theory-of-interacting-dirac-fermions-in-two-dimensions-and-the-dark-
 side-of-the-gross-neveu-model
CATEGORIES:Talks & Lectures
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