Published on February 18, 2022 Updated on March 7, 2022


Fakher Assaad
Fakher Assaad
University of Würzburg - Germany
Visiting Scholar invited by research center LPTM
Curriculum Vitae


Research project

Numerical simulations of graphene nanoflakes

During the visit, Prof. Assaad and Honecker will pursue their collaboration [1][2] on numerical simulations of graphene nanoflakes. We will continue our detailed comparison of various numerical approaches such as mean-field theory, real-space dynamical mean-field-theory (DMFT) and full-blown lattice quantum Monte Carlo (QMC) simulations along the lines of a recent common publication [3]. Here, the key question is to assess how far each approach can reliably describe aspects of the many-body physics emerging in graphene. We will then concentrate on a recent proposal of realizing the so-called Sachdev-Ye-Kitaev (SYK) model graphene nanoflakes put forward by the group of M. Franz [4]. This model has attracted a lot of interest since it is exactly solvable in the large-N limit, and has been shown to exhibit physical properties characteristic of black holes. Here the combination of a disordered boundary - that does not break chiral symmetry - as well as strong orbital magnetic fields, shows that the SYK model may be realized after projection onto the lowest Landau level. Here we plan to carry out exact diagonalization calculations in the projected Hilbert space of the lowest Landau level as well as real-space DMFT and lattice QMC simulations. The key objective is to assess if this fascinating state of matter is realized in the graphene nanoflake or if instabilities to chiral symmetry breaking states prohibit the emergence of this state. The visit of Prof. Assaad will allow face-to-face discussions and thus enable us to push these ongoing collaborations forward more efficiently. In addition, Prof. Assaad is an internationally highly respected scientist (currently approx. 140 publications in the Web of Science Core Collection with h=33) whose presence will be an enrichment for the Université de Cergy-Pontoise.