Weekly seminars

Critical properties of graphene and supergraphene

par Simon Metayer (LPTHE - Laboratoire de Physique Théorique et Hautes Energies)

Europe/Paris
Salle des sommets (LAPTh)

Salle des sommets

LAPTh

9, chemin de Bellevue ANNECY
Description

We delve into the impact of electronic interactions in several 
variants of low-dimensional quantum electrodynamics using both 
perturbative and non-perturbative analytical methods. To motivate such 
activities, and for a pedagogical approach, we will primarily focus on 
the outstanding example of graphene and we also examine a minimally 
supersymmetric extension related to potential supergraphene materials. 
Such correlated planar fermionic quantum systems from condensed matter 
may be subject to interaction-driven phase transition in low-energy 
conditions. These phase transitions are characterized by anomalous 
dimensions, or equivalently critical exponents, which are universal 
physical quantities computed using multiloop Feynman diagram techniques. 
After a brief introduction to the renormalization of field theories, we 
compute for these models their optical conductivity as well as all their 
critical exponents, through loop or large Nf expansions beyond the 
leading order. We explore the possibility of a metallic-to-insulating 
phase transition through the generation of a dynamical mass for the 
electron. Our results unveil new physics beyond the leading order and 
suggest that supergraphene could be strikingly different from regular 
graphene.