[seminar] Zajednički seminar IF-a i ZCI QuantiXLie u četvrtak 25.10.2018. u 11:00h - dr. Andrei Fedorenko (Lyon)

[Damir Staresinic]

ZAJEDNIČKI SEMINAR INSTITUTA ZA FIZIKU I ZNANSTVENOG CENTRA IZVRSNOSTI QuantiXLie 





Institut za fiziku, Bijenička cesta 46, 

predavaonica u zgradi Mladen Paić četvrtak, 25. listopada 2018., u 11:00 sati 
Disorder-driven quantum transition in relativistic semimetals 
dr. Andrei A. Fedorenko 
Centar za Ecole Normale Supérieure , Lyon, France 



The recent discovery of materials whose electronic properties are described by three-dimensional relativistic fermions opened fascinating opportunities to study physical phenomena which have never been accessible before. Among these phenomena is a remarkable disorder-driven quantum transition in the simplest relativistic phases, the Weyl semimetals. This transition is fascinating: it is different from the Anderson transition, yet accessible experimentally. Despite a burst of papers, the understanding of this transition is still lacking. A standard approach relates this transition to the U(N) Gross-Neveu model in the limit of N →0 [1]. However, there is little agreement between the predictions of numerical simulations and the various analytical results derived from the Gross-Neveu model. 

Recently we have developed a functional renormalization group amenable to include non-analytic effects [2]. We show that the previously considered fixed point is infinitely unstable, demonstrating the necessity to describe fluctuations beyond the usual Gaussian approximation. Furthermore, the disorder distribution renormalizes following the so-called porous medium equation which appears in different context in fluid mechanics, mathematical biology, boundary layer theory, and other fields. We relate self-similar solutions of the porous medium equation to a universal mechanism of generation of finite density of states responsible for the transition. We find that the transition is controlled by a non-analytic fixed point drastically different from the fixed point of the U(N) Gross-Neveu model. Our findings provide a framework for extensions to problems ranging from the mass generation at the chiral symmetry breaking transitions in the high energy physics to non-linear sigma models with infinitely many relevant operators. 

[1] T. Louvet, D. Carpentier, A. A. Fedorenko, Phys. Rev. B 94 , 220201(R) (2016) 

[2] I. Balog, D. Carpentier, A. A. Fedorenko, arXiv:1710.07932 (to appear in Phys. Rev. Lett.) 




Voditelji seminara IF-a: [ mailto:hrvoje at ifs.hr | Hrvoje Skenderović ] i [ mailto:damirs at ifs.hr | Damir Starešinić ] 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.phy.pmf.unizg.hr/pipermail/seminar/attachments/20181018/a6c0daef/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: QuantiXlie.jpg
Type: image/jpeg
Size: 13865 bytes
Desc: not available
URL: <http://www.phy.pmf.unizg.hr/pipermail/seminar/attachments/20181018/a6c0daef/attachment-0002.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: logo_IF_seminar.jpg
Type: image/jpeg
Size: 9859 bytes
Desc: not available
URL: <http://www.phy.pmf.unizg.hr/pipermail/seminar/attachments/20181018/a6c0daef/attachment-0003.jpg>