This event is part of a regular series of meetings on Quantum and Topological Matter, sponsored by Delta ITP. The objective is to bring together the theoretical physics communities in Amsterdam, Leiden and Utrecht. We encourage researchers from different areas in theoretical physics to participate! 

Programme

14:00 Coffee/tea and cookies

14:30 Lars Fritz (Utrecht)

Universality and scaling in a charge two-channel Kondo device 

15:30 Jorrit Kruthoff (Amsterdam)

Current status of the classification of topological phases

16:30 Coffee break 

17:00 Charles Kane (University of Pennsylvania & Leiden)

Symmetry Protected Topological Insulators and Semimetals

Abstracts

14:30 Lars Fritz (Utrecht) - Universality and scaling in a charge two-channel Kondo device 

Abstract: We study a charge two-channel Kondo model, demonstrating that recent experiments [Iftikhar et al, Nature 526, 233 (2015)] realize an essentially perfect quantum simulation – not just of its universal physics, but also nonuniversal effects away from the scaling limit. Numerical renormalization group calculations yield conductance lineshapes encoding RG flow to a critical point involving a free Majorana fermion. By mimicking the experimental protocol, the experimental curve is reproduced quantitatively over 9 orders of magnitude, although we show that far greater bandwidth/temperature separation is required to obtain the universal result. Fermi liquid instabilities are also studied: In particular, our exact analytic results for non-linear conductance provide predictions away from thermal equilibrium, in the regime of existing experiments.

15:30 Jorrit Kruthoff (Amsterdam) - Current status of the classification of topological phases

Abstract: In this talk I will give a short status update of the classification of topological phases. I'll start with a discussion on the free fermion systems with an emphasis on crystal symmetries and in particular focus on a two dimensional system in class A with space group p4mm. Next I will consider the classification of symmetry protected topological (SPT) phases and show that in order to classify these phase we need to consider a beautiful mathematical framework: cobordism theory.

17:00 Charles Kane (University of Pennsylvania & Leiden) - Symmetry Protected Topological Insulators and Semimetals 

Abstract: We will discuss recent developments in topological band theory, in which the combination of time reversal symmetry and crystal symmetries lead to novel insulating and semimetallic states. We will discuss weak topological insulators and topological crystalline insulators along with their symmetry protected surface states, as well as bulk topological semimetals that feature point and line nodes in their electronic structure that are protected by symmorphic and/or non-symmorphic space group symmetries. 

Location 

Leiden University, Huygens Laboratory, Room HL 226/228

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Local organisers

Cristiane Morais Smith (Utrecht)

Vadim Cheianov (Leiden)

Vladimir Gritsev (Amsterdam)