Janus Juul Eriksen

Photo: Lars Kruse, AU Foto (2017)

Welcome to my personal research website. Here you'll find information on my research interests, previous teaching experiences, as well as publications and oral disseminations.

As of March 2021, my affiliation is with the Technical University of Denmark (DTU) where I'm an assistant professor in the Department of Chemistry, funded by a Villum Young Investigator award (2021-26). Prior to commencing work at DTU, I was working at the University of Bristol in the group of Prof. Fred Manby where I was funded by an international postdoctoral fellowship granted by the Independent Research Fund Denmark (2019-21). Before leaving for Bristol, I was working with Prof. Jürgen Gauss at the Johannes Gutenberg-Universität Mainz, funding by a postdoctoral fellowship granted by the Alexander von Humboldt Stiftung (2017-19). My PhD studies (2013-16) were conducted in the group of Prof. Poul Jørgensen at Aarhus University.

For a full account of publications, presentations, and peer review activities, please see the Publications and Presentation sections as well as my Google Scholar and Publons profiles.

News

  • 27-04-2021: I've got a new paper, “Decomposed Mean-Field Simulations of Local Properties in Condensed Phases” by Eriksen, on arXiv today (arXiv: 2104.12480). In the letter, I've used my recent theory for decomposing Kohn-Sham DFT simulations [Eriksen, J. Chem. Phys. 153, 214109 (2020)] to separate out local solvation properties (monomer ground-state energies and dipole moments) within liquid, ambient water.

  • 01-03-2021: I've now officially commenced my new position as an assistant professor at DTU Chemistry. See Contact for my new e-mail and physical address and please don't hesitate to get in touch.

  • 28-02-2021: Our new invited review on incremental approaches to the exact diagonalization problem in electronic structure theory, “Incremental Treatments of the Full Configuration Interaction Problem” by Eriksen & Gauss, has been published in WIREs Comput. Mol. Sci.: DOI: 10.1002/wcms.1525.

  • 22-01-2021: Over the moon to be named among this year's Villum Young Investigators. I can't wait to get started at DTU Chemistry in March, embarking on five years of research on decomposed quantum chemistry. Truly grateful to The Villum Foundation for this starting grant and the support. At the same time, I'll unfortunately have to relinquish my recent Reintegration Fellowship from The Carlsberg Foundation as a consequence.

  • 25-12-2020: My invited perspective on near-exact electronic structure theory is now out in JPCL, subtly disguised as an homage to the late and great Ornette Coleman: DOI: 10.1021/acs.jpclett.0c03225.

  • 15-12-2020: I've been invited to write a short review on the MBE-FCI approach to exact electronic structure theory for WIREs Comput. Mol. Sci.: “Incremental Treatments of the Full Configuration Interaction Problem” by Eriksen & Gauss (arXiv: 2012.07371). As always, feedback is welcome. Our work will hopefully work to clarify what the pros & cons of this sort of method are in various practical applications.

  • 04-12-2020: More good news - my paper on mean-field decompositions by means of localized orbitals, “Mean-Field Density Matrix Decompositions” by Eriksen, has now been published in JCP, as part of their 2020 JCP Emerging Investigators Special Collection: DOI: 10.1063/5.0030764.

  • 03-12-2020: I'm truly honoured to have been named among this year's recipients of a Carlsberg Foundation Reintegration Fellowship, which will allow me to return back home to Denmark (DTU Chemistry) in March 2021 and further develop my scientific career. Huge thanks to The Carlsberg Foundation for the support.

  • 26-10-2020: I've been invited to write a perspective on modern-day exact electronic structure theory, which has now appeared on arXiv: “The Shape of FCI to Come” by Eriksen (arXiv: 2010.12304). The paper provides a (hopefully) succinct account of today's state-of-the-art as well as my personal views on what's to come.

  • 22-10-2020: The foreword to this year's Mol. Phys. Festschrift in honour of Jürgen Gauss, which I've had the privilege of guest-editing alongside Stella Stopkowicz (Mainz), Thomas Jagau (Leuven) & Trygve Helgaker (Oslo), has now appeared online. DOI: 10.1080/00268976.2020.1817247.

  • 16-10-2020: Our new paper on the extension of MBE-FCI theory to properties for ground and excited states, Ground and Excited State First-Order Properties in Many-Body Expanded Full Configuration Interaction Theoryby Eriksen & Gauss, has been published in JCP: DOI: 10.1063/5.0024791.

  • 07-10-2020: Our new paper on the benzene blind challenge, The Ground State Electronic Energy of Benzeneby Eriksen et al., has been published in JPCL: DOI: 10.1021/acs.jpclett.0c02621.

  • 24-09-2020: A new paper on “Mean-Field Density Matrix Decompositions” by Eriksen (arXiv: 2009.10837) has appeared on arXiv today. The paper introduces a new way of decomposing mean-field electronic structure theories (with applications to HF & KS-DFT) by means of localized MOs and various charge population protocols. I further demonstrate how decomposed mean-field theory makes it possible to expose and amplify compositional features in the context of machine-learned quantum chemistry.

  • 11-08-2020: Two new papers have appeared on arXiv within the past week. In arXiv: 2008.02678 (The Ground State Electronic Energy of Benzeneby Eriksen et al.), we report on a blind challenge devoted to the determination of the FCI ground state energy for the benzene/cc-pVDZ system, with involvement from most of the current state-of-the-art approaches from all around the world. In arXiv: 2008.03610 (Ground and Excited State First-Order Properties in Many-Body Expanded Full Configuration Interaction Theoryby Eriksen & Gauss), MBE-FCI theory is extended to excited states and static first-order properties different from total, ground state correlation energies. Both papers have been submitted for publication.

  • 13-07-2020: Our new paper on the PySCF program has been published in JCP: DOI: 10.1063/5.0006074.

  • 16-03-2020: My forthcoming seminar at King's College London has been cancelled/rescheduled due to COVID-19. Bummer.

  • 02-03-2020: A new preprint on recent developments in the PySCF program package has been submitted for publication in a special issue of JCP on electronic structure software. A preprint is available on arXiv: 2002.12531.

  • 20-02-2020: I've been invited by George Booth @ the Department of Physics, King's College London to present a seminar on MBE-FCI theory on Tuesday, March 31st. Looking very much forward to the visit! (UPDATE 16-03-2020: Cancelled/rescheduled due to COVID-19).

  • 13-02-2020: I am pleased to announce that our proposal for the 2020 HPC Call @ Johannes Gutenberg-Universität Mainz, Germany, has been awarded a total of 10.0M core-hours on their MogonII system. The project will be concerned with the application of our MBE-FCI method to the field of computational thermochemistry and the allocation will run for the next year.

  • 11-12-2019: I've been invited by Nick Blunt & Alex Thom @ the Department of Chemistry, University of Cambridge to present a seminar on MBE-FCI theory on Wednesday, February 2nd next year. Looking very much forward to the visit!

  • 27-11-2019: Our paper entitled “Generalized Many-Body Expanded Full Configuration Interaction Theory” (Eriksen & Gauss) is out now in JPCL. DOI: 10.1021/acs.jpclett.9b02968

  • 09-10-2019: Our paper entitled “Generalized Many-Body Expanded Full Configuration Interaction Theory” (Eriksen & Gauss) has been submitted for publication. A preprint is available on arXiv: 1910.03527.

  • 07-10-2019: The PyMBE code is now open source: https://gitlab.com/januseriksen/pymbe

  • 09-09-2019: I'm contributing to this month's C&EN Magazine with an essay (Nomadic Tales) on my postdoctoral experience. Link: https://cen.acs.org/careers/postdocs/Postdoc-perspective-Tales-nomadic-postdoc/97/i35

  • 05-08-2019: Our “Many-Body Expanded Full Configuration Interaction. II. Strongly Correlated Regime” (Eriksen & Gauss) paper is out now in JCTC. DOI: 10.1021/acs.jctc.9b00456

  • 09-05-2019: Our paper entitled “Many-Body Expanded Full Configuration Interaction. II. Strongly Correlated Regime” (Eriksen & Gauss) has been submitted for publication. A preprint is available on arXiv: 1905.02786.

  • 10-04-2019: My abstract for an oral contribution at the MQM2019 meeting (Heidelberg, Germany) later this year has been accepted. I intend to talk about recent enhancements of the MBE-FCI method and its application to increasingly larger system sizes.

  • 27-03-2019: I am pleased to announce that my proposal for the 18th PRACE Project Access Call has been awarded a total of 26.4M core-hours on the MARCONI system @ Cineca, Bologna, Italy. The project will be concerned with the application of our MBE-FCI method to the field of computational thermochemistry and the allocation will run for the next year.

  • 11-02-2019: After 2.5 fruitful and truly enjoyable years in Mainz, I am relocating to Bristol, UK to start a new leg of postdoctoral research by 01-03-2019, this time generously funded by the Independent Research Fund Denmark. My new host for the coming 2 years will be Prof. Fred Manby and we will work towards accelerating and enhancing the MBE-FCI method even further in continued close collaboration with Prof. Jürgen Gauss in Mainz.

  • 22-10-2018: I will present our latest research on MBE-FCI at the Methods and Algorithms in Quantum Chemistry conference (Aarhus, Denmark), December 13-16, 2018.

  • 20-08-2018: Our “Many-Body Expanded Full Configuration Interaction. I. Weakly Correlated Regime” (Eriksen & Gauss) paper is out now in JCTC. DOI: 10.1021/acs.jctc.8b00680

  • 07-08-2018: I will present our latest research on MBE-FCI at the joint Mainz-Kobe workshop on Solving the Full Configuration Interaction Problem (Kobe, Japan), November 26-27, 2018.

  • 04-07-2018: Our paper entitled “Many-Body Expanded Full Configuration Interaction. I. Weakly Correlated Regime” (Eriksen & Gauss) has been submitted for publication. A preprint is available on arXiv: 1807.01328.

  • 01-07-2018: I will present our latest research on MBE-FCI at the Molecular Electronic Structure conference (Metz, France), August 28-31, 2018.

  • 28-06-2018: I presented our latest research on MBE-FCI at the 16th ICQC satellite meeting on Strong correlation in electronic structure theory (Strasbourg, France), June 24-27, 2018.

  • 08-06-2018: I presented our latest research on MBE-FCI at the Low-scaling and Unconventional Electronic Structure Techniques conference (Telluride, CO, US), June 04-07, 2018.