ELFT HÍRADÓ

[Dr. Dóra Balázs <dora.balazs AT ttk.bme.hu>]

                      MEGHÍVÓ








    a Szilárd Leó-Kollokvium előadására:



                      Igor Herbut
            (Simon Fraser University)




“Unified theory of interacting Dirac fermions in two dimensions     (and the 
dark side of the Gross-Neveu model)"

Kivonat:  Quasi-relativistic gapless (or "massless") Dirac fermions appear as 
low-energy excitations in many condensed matter systems of recent interest.  
They are often weakly interacting, as famously in graphene, but at stronger 
interactions 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 transition" from gapless semimetal  to gapped insulator, believed to be 
observed recently in twisted multilayers.

I will discuss the recent attempt of unification of all order parameters for 
Dirac systems in two dimensions based on large but somewhat hidden orthogonal 
symmetry of free Dirac fermions. Interestingly, the unique interacting field 
theory that respects such an orthogonal symmetry turns out to be equivalent 
to the celebrated Gross-Neveu model.  I will argue that, in spite of recently 
turning 50, this model still has a large, unexplored, and surprisingly 
interesting region of its coupling constant.  Recent analytical and numerical 
results relevant to this "dark side" of the Gross-Neveu model will be 
presented.




Helye: BME Fizikai Intézet, Fizika Tanszék
Budafoki út 8. F-épület, 2. emelet, 13-as terem


Ideje: 2026. április 28. (kedd), 14:30.
Kapunyitás 14:14-től.
Program: http://physics.bme.hu/kollokvium


Minden érdeklődőt örömmel várunk!





Dóra Balázs és Zaránd Gergely