[Todos] Charla de materia condensada, martes 14, 11 hs

[Pablo I. Tamborenea]

Hola,

El grupo de materia condensada teoría los invita a una charla a cargo
del Prof. Bitan Roy, el martes 14/03 a las 11 hs, en el aula Federman.

Saludos,

Alberto, Gustavo, Pablo



Title: Dynamic mass generation on electronic hyperbolic lattices

Abstract: From table salts to quantum materials, crystals are  
ubiquitous in nature. They foster a plethora of exotic quantum  
phenomena, such as superconductivity, non-Fermi liquid, topological  
insulators to name a few. However, the number of symmetry allowed  
crystals that plays a crucial role in determining such emergent  
quantum behavior is restricted on flat Euclidean space, permitting  
only triangular, square and honeycomb lattices. On the other hand,  
negatively curved two-dimensional Poincare disk harbors infinitely  
many periodic hyperbolic lattices, thereby opening a rich landscape of  
quantum phenomena on curved space.
In this talk, first I will introduce the construction of hyperbolic  
lattices on Poincare disk and contrast their symmetries with flat  
Euclidean lattices. I will then show that simple tight-binding model  
allows a simple classification of a family of quantum hyperbolic  
crystals in terms of the density of states near half-filling,  
featuring Dirac liquid, Fermi liquid and flat bands respectively  
characterized by vanishing, constant and diverging density of states  
near the half-filling.
I will argue that in all these systems, nearest-neighbor Coulomb and  
onsite Hubbard repulsion favor nucleation of a charge-density-wave and  
an antiferromagnet, respectively, and discuss their scaling  
properties. While these orders develop for sufficiently weak coupling  
in hyperbolic Fermi liquids and flat bands, the Dirac systems by  
contrast showcase quantum critical points only beyond which any  
ordering stabilizes. I will also show that curvature reduces the  
requisite critical strength of interactions in comparison to their  
counterparts in flat Euclidean Dirac material, such as graphene.
Finally, I will show that application of strong magnetic field  
catalyzes these orderings in hyperbolic Dirac materials for  
infinitesimal interactions. I will close the talk by highlighting some  
future directions.

Short-Bio sketch: Bitan Roy is a theoretical condensed matter  
physicist and currently he is an Assistant Professor at Lehigh  
University (https://www1.lehigh.edu/). Prof. Roy received his PhD from  
Simon Fraser University, Canada. Subsequently, he was a postdoctoral  
fellow at the National High Magnetic Field Laboratory, Florida,  
University of Maryland and at Rice University, Houston. Before joining  
Lehigh, he was a Staff Scientist at the Max Planck Institute for the  
Physics of Complex System, Dresden, Germany for two years. Prof. Roy’s  
research is broadly focused on strongly correlated and disordered  
systems, and topological phases of matter.  Prof. Roy is also a  
recipient of NSF Early Career Award.





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Prof. Pablo I. Tamborenea
Departamento de Física
Universidad de Buenos Aires
http://users.df.uba.ar/pablot/
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