Patrick Lenggenhager

Patrick Lenggenhager
ETH Zurich | ETH Zürich · Department of Physics

MSc ETHZ Physics

About

9
Publications
1,073
Reads
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46
Citations
Additional affiliations
November 2019 - present
Paul Scherrer Institut
Position
  • PhD Student
November 2019 - present
University of Zurich
Position
  • PhD Student
September 2018 - present
ETH Zurich
Position
  • Research Assistant
Education
November 2019 - November 2023
ETH Zurich
Field of study
  • Physics
September 2016 - March 2019
ETH Zurich
Field of study
  • Physics
September 2012 - October 2015
ETH Zurich
Field of study
  • Physics

Publications

Publications (9)
Preprint
Full-text available
The Bloch band theory describes energy levels of crystalline media by a collection of bands in momentum space. These bands can be characterized by non-trivial topological invariants, which via bulk-boundary correspondence imply protected boundary states inside the bulk energy gap. Recently, hyperbolic lattices that tile the negatively curved hyperb...
Preprint
Full-text available
We analyze triply degenerate nodal points [or triple points (TPs) for short] in energy bands of crystalline solids. Specifically, we focus on spinless band structures, i.e., when spin-orbit coupling is negligible, and consider TPs formed along high-symmetry lines in the momentum space by a crossing of three bands transforming according to a 1D and...
Preprint
Full-text available
The Laplace operator encodes the behaviour of physical systems at vastly different scales, describing heat flow, fluids, as well as electric, gravitational, and quantum fields. A key input for the Laplace equation is the curvature of space. Here we demonstrate that the spectral ordering of Laplacian eigenstates for hyperbolic (negative curvature) a...
Preprint
Full-text available
Triple nodal points are degeneracies of energy bands in momentum space at which three Hamiltonian eigenstates coalesce at a single eigenenergy. For spinless particles, the stability of a triple nodal point requires two ingredients: rotation symmetry of order three, four or six; combined with mirror or space-time-inversion symmetry. However, despite...
Article
Full-text available
We study a class of topological materials which in their momentum-space band structure exhibit threefold degeneracies known as triple points. Focusing specifically on PT-symmetric crystalline solids with negligible spin-orbit coupling, we find that such triple points can be stabilized by little groups containing a three-, four-, or sixfold rotation...
Preprint
Full-text available
We study a class of topological materials which in their momentum-space band structure exhibit threefold degeneracies known as triple points. Focusing specifically on PT-symmetric crystalline solids with negligible spin-orbit coupling, we find that such triple points can be stabilized by little groups containing a three-, four-, or sixfold rotation...
Article
Full-text available
Recently, a novel real-space renormalization group (RG) algorithm was introduced. By maximizing an information-theoretic quantity, the real-space mutual information, the algorithm identifies the relevant low-energy degrees of freedom. Motivated by this insight, we investigate the information-theoretic properties of coarse-graining procedures for bo...
Preprint
Full-text available
Recently a novel real-space RG algorithm was introduced, identifying the relevant degrees of freedom of a system by maximizing an information-theoretic quantity, the real-space mutual information (RSMI), with machine learning methods. Motivated by this, we investigate the information theoretic properties of coarse-graining procedures, for both tran...
Preprint
Full-text available
Recently a novel real-space RG algorithm was introduced, identifying the relevant degrees of freedom of a system by maximizing an information-theoretic quantity, the real-space mutual information (RSMI), with machine learning methods. Motivated by this, we investigate the information theoretic properties of coarse-graining procedures, for both tran...

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Projects

Project (1)
Project
The goal of this project is to classify triple nodal points in spinless systems and understand possible boundary signatures. See also: https://patrick-lenggenhager.github.io/projects/2020/08/06/TriplePoints.html.