The goal of quantumchemical calculations is the simulation of materials and molecules. In densityfunctional theory (DFT) the first step along this line is obtaining the electron density minimising an energy functional. However, since energies and the density are usually not very tractable quantities in an experimental setup, comparison to experiment …
read moreCECAM flagship workshop: Error control in firstprinciples modelling
(Crosspost from our report published in the Psik blog)
From 20th until 24th June 2022 I coorganised a workshop on the theme of Error control in firstprinciples modelling at the CECAM Headquarters in Lausanne (workshop website). For one week the workshop unified likeminded researchers from a range of communities, including …
read moreGdR nbody general meeting
About two weeks ago, from 10 till 13 Jan 2022 I was at the annual meeting of the French research group on manybody phaenomena, the GDR nbody. Originally scheduled to take place in person in Toulouse the Coronarelated developments unfortunately caused the organisers to switch to a virtual event on …
read moreOutlook to 2022
A quick teaser to some workshops I will organise next year.

17/18 Feb 2022: Introduction to the Julia programming language (virtual).
In two halfday sessions I will provide a concise overview of the Julia programming language and offer to get some handson practice. The selection of exercises and small …

GdR REST Discussion meeting on Machine Learning
Last week on 9th and 10th December 2021 I participated in the Discussion meeting on Machine Learning been organised by the French research group REST, which is centred around theoretical spectroscopy in solids and molecules. While most participants joined remotely I was fortunately able to travel to École Polytechnique in …
read moreA robust and efficient line search for selfconsistent field iterations
In an ongoing effort with Antoine Levitt our aim is to develop reliable densityfunctional theory (DFT) methods for computational materials design. Recently we looked into a strategy to automatically select the damping parameter for the selfconsistent field iterations (SCF). Our adaptive damping approach is based on a theoretically sound quadratic …
read moreJuliaCon DFTK workshop: A mathematical look at electronic structure theory
From 13th July till 30th July this year's JuliaCon finally took place virtually. The first week (13th till 27th) hosted a number of threehour livestreamed sessions of workshops, while the "regular" conference with a number of prerecorded talks started on 28th.
After my introductory talk to electronic structure theory and …
read moreVirtual materials design 2021: Blackbox densityfunctional theory methods
On 20th and 21st July 2021 the Virtual Materials Design 2021 CECAM workshop took place virtually. I was excited about this workshop and the opportunity to get in touch with researchers working on highthroughput computational materials design. While I am not actively working in this field the special requirements of …
read moreSSD Seminar: Accelerating the discovery of tomorrow's materials by robust and errorcontrolled simulations
A couple of days ago, on 12th July, I was invited to present my research in the SSD Seminar Series of RWTH Aachen. Being part of the research training group on modern inverse problems as well as the School for Simulation and Data Science (SSD) the SSD seminars are interdisciplinary …
read moreTalk at manybody seminar at RWTH
On 29th June I was invited to present a short summary of my research at the seminar of the research training group Quantum ManyBody Methods at RWTH Aachen University. In the talk I give a overview over my ongoing work about reliable blackbox selfconsistent field schemes for highthroughput DFT calculations …
read moreErrors and uncertainty quantification in densityfunctional theory
On 8th June I was invited to the seminar of the Uncertainty Quantification (UQ) group of Prof. Youssef Marzouk at MIT. Youssef and I planned to have this seminar since my involvement with MIT's CESMIX project last February (see also this blog article), but it took use quite some time …
read moreTalk at MATH4UQ seminar series at RWTH
On 1st June I was invited to the MATH4UQ seminar series of the Mathematics of Uncertainty Quantification chair of Prof. Raul Tempone at RWTH Aachen University.
Over the past months I got more and more interested in mathematical methods for uncertainty quantification (UQ) as an opportunity to estimate and understand …
read moreSIAM LA: Robust and efficient accelerated methods for densityfunctional theory
Just one day after my talk at the SIAM Materials Science conference (blog article) I gave another talk at a SIAM meeting, this time at SIAM Linear Algebra. I was very much looking forward to participate in SIAM LA, firstly because it was the first time I attended this conference …
read moreSIAM MS: Using the densityfunctional toolkit to design blackbox DFT methods
After being moved by one year due to the pandemic, the last two weeks (from 17th to 28th May) the SIAM materials science conference finally took place in virtual form. Unfortunately this meant that the conference was scheduled in parallel to the SIAM Linear Algebra virtual conference, where I also …
read moreTalk at Lüchow group seminar at RWTH
On 5th May I was invited to present a short summary of my research at the local theoretical chemistry research group of Prof. Dr. Arne Lüchow at RWTH Aachen. Because I wanted to give a broad overview of topics that I worked on over the past few years, I did …
read moreThoughts on initial guess methods for DFT
On Thursday I gave a brief talk in our weekly ACED differentiate group meeting about initial guess methods for starting selfconsistent field calculations in methods such as densityfunctional theory. For preparing the talk I did a little digging into both the standard approaches used by many molecular and solidstate codes …
read moreA novel blackbox preconditioning strategy for highthroughput densityfunctional theory
A couple of weeks ago, from 15th to 19th March, I participated in the virtual annual meeting of the German Association of Applied Mathematics and Mechanics (GAMM). For me this meeting was the first time I presented my work to an audience of applied mathematicians with a broad background and …
read morePostDoc position at Appl. & Comput. Mathematics lab, RWTH Aachen University
This week I started my new position as a postdocotoral researcher at the Applied and Computational Mathematics (ACoM) research lab at RWTH Aachen University. The lab consists of two interdisciplinary research groups, namely the group of Prof. Dr. Manuel Torrilhon, who works on the mathematical modelling and simulation of technical …
read moreCESMIX TST meeting: DFTK.jl: A multidisciplinary Julia code for densityfunctional theory development
These past two days I have participated in the TriLab Support Team (TST) meeting of the CESMIX, the newly founded Center for the Exascale Simulation of Material Interfaces in Extreme Environments at the Massachusetts Institute of Technology. Within the next few years the idea of the CESMIX is to develop …
read moreHighthroughput densityfunctional theory calculations: An interdisciplinary challenge
Last Thursday I was invited to give a virtual talk at the Scientific Computing Seminar of working group of Prof. Nicolas Gauger at TU Kaiserslautern. Since the research in Prof. Gauger's group mostly concerns topics which are not directly related to electronic structure theory and densityfunctional theory (DFT), I chose …
read moreBlackbox inhomogeneous preconditioning for selfconsistent field iterations in densityfunctional theory
For the past half a year or so Antoine Levitt and myself have been looking at a particular tricky busyness for solidstate densityfunctional theory (DFT) calculations, namely how to design efficient selfconsistent field (SCF) schemes for large inhomogeneous systems. I have already previously reported on this matter in a short …
read moreFirst release of the densityfunctional toolkit (DFTK)
After we released a preliminary snapshot of DFTK last year our focus in the first half of this year was on using it for some new science. Recently, however, we got back into polishing our code base and our documentation in order to get DFTK ready for a wider audience …
read moreA posteriori error estimation for the nonselfconsistent KohnSham equations
After about a year of work on the densityfunctional toolkit (DFTK) we finally started using the code for some new science. Given the mathematics background of the CERMICS the first two DFTKrelated articles were not so much about largescale applications, but rather deal some fundamental questions of KohnSham densityfunctional theory …
read morePreview release of the densityfunctional toolkit (DFTK)
As part of my research stay at the Matherials team of ENPC Paris Tech and Inria I have been developing the densityfunctional toolkit, DFTK.jl, together with Antoine Levitt and Eric Cancès. Finally after about six months of joint effort on this Julia code, we just released a first preview …
read morePostDoc position at CERMICS / Sorbonne Université
Last week I started my new position as a postdoctoral fellow at the MATHERIALS team of the Centre d'Enseignement et de Recherche en Mathématiques et Calcul Scientifique (CERMICS) laboratory and Inria Paris with an additional affiliation to the Institut des Sciences du Calcul et des Données at Sorbonne Université. As …
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