Janus Juul Eriksen

Photo: Lars Kruse, AU Foto (2017)

Welcome to my personal research website. Here you will find information about my research interests, previous teaching experience, as well as publications and oral disseminations.

As of March 2019, my affiliation is with the University of Bristol in the group of Prof. Fred Manby where I am funded from an international postdoctoral fellowship granted by the Independent Research Fund Denmark (2019-2021). Prior to commencing work in Bristol, I have been working with Prof. Jürgen Gauss at the Johannes Gutenberg-Universität Mainz with funding from a postdoctoral fellowship granted by the Alexander von Humboldt Stiftung (2017-2019). My PhD studies (2013-2016) were conducted in the group of Prof. Poul Jørgensen at Aarhus University.

My current research is focused on a novel near-exact treatment of the electron correlation problem in quantum mechanics, as implemented in the recently proposed many-body expanded full configuration interaction (MBE-FCI) method. Previous research interests include the development of non-iterative and local coupled cluster methods as well as the high-performance computing implementation of these on standard CPU and general purpose graphics processing unit (GPU) architectures. The Research section provides additional details on past and current research interests.

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

  • 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.