Universality in Disordered Quantum Systems
Projects
Theoretically analysing first principle models of disordered quantum systems, such as quantum dots or quantum wires, is extremely challenging and often impossible. However, most macroscopically observable emergent phenomena, e.g. electric conductivity, are universal. They do not depend on microscopic details. Together with two PhD students and three postdocs, we will make use of this fact by investigating and classifying such phenomena within more accessible coarse-grained random matrix models.
Quantum Transport and Scattering
We will study transport properties of disordered quantum systems, such as quantum dots and quantum wires, modelling the system components by random matrices. The simplest instance of such a model is the quantum dot, which does not have an internal structure. We recently analysed this model in 'Scattering in quantum dots via noncommutative rational functions'.
Universal Scattering Resonances
The scattering matrix describes how a quantum particle is scattered upon entering a disordered medium. The resonances of this S-matrix contain information about the energy content of exitable metastable states within the system, as well as about their lifetime. We will study universal properties of these resonances.
Quantum Diffusion
The problem of describing the diffusion of a quantum particle in a disordered environment is connected to deep mathematical conjectures such as the BGS-quantum chaos conjecture, the extended states conjecture by Fyodorov-Mirlin and the conjectured metal-insulator phase transition of the Anderson-model. Some of these have been open for half a century. The main challenge is to understand the metallic or delocalised phase of the system. We will study random band matrices, a heuristic model for quantum diffusion, for which major breakthroughs have been achived in recent years.
News
19 August 2021: 'Singularity degree of structured random matrices' published on arXiv
05 August 2021: 'Scattering in quantum dots via noncommutative rational functions' published in Annales Henri Poincaré
20 March 2021: Project 'Dynamics on Correlated Networks' announced at Department of Mathematical Sciences in Copenhagen (here).
01 March 2021: Jonas Raunsø Håkånsen joins the project 'Dynamics on Correlated Networks' as research assistant
05 Febuary 2021: 'Local elliptic law' published on arXiv
01 January 2021: Start of related project 'Dynamics on Correlated Networks', funded by Novo Nordisk Foundation
01 October 2020: Meng Yang joins the team as postdoc
01 September 2020: Peter Krarup joins the team as PhD student
01 August 2020: Jacob Fronk joins the team as PhD student
01 July 2020: Start of Project
23 January 2020: Project announced at Department of Mathematical Sciences in Copenhagen (here).
23 January 2020: Funding for the project recieved through the Villum Young Investigator Program.
12 November 2019: 'Scattering in quantum dots via noncommutative rational functions' published on arXiv.