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Janus Juul Eriksen

@januseriksen.bsky.social
744 followers 177 following 75 posts

Assoc. prof. in #compchem at DTU (🇩🇰) -- Previously: Bristol Uni (🇬🇧) & Uni Mainz (🇩🇪). Member of @theyoungacademydk.bsky.social (🇩🇰, 2022-27).

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Reposted by Janus Juul Eriksen
Martin Rahm @rahmlab.bsky.social · 23/09/2026
PhD position at Chalmers University of Technology in 🇸🇪: computational materials design of carbon- and oxygen-based conductors! @chemjobber.bsky.social @thephdplace.bsky.social #PhDposition #CondensedMatter #CompChem #ChemSky #AcademicSky www.chalmers.se/en/about-cha...
chalmers.se
Vacancies
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Janus Juul Eriksen @januseriksen.bsky.social · 16/09/2026
Deadline on September 25th is approaching soon. Please get your applications in and reach out to me by email beforehand with any questions you might have. RTs are most welcome.
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Janus Juul Eriksen @januseriksen.bsky.social · 28/08/2026
Don't care much for donuts but I love Tiny Tim!
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Janus Juul Eriksen @januseriksen.bsky.social · 27/08/2026
I'm looking for a talented, motivated, and ambitious candidate for an open postdoc position in my group at DTU in the greater CPH area. This call has an emphasis on ML applied within chem/phys and proven skills are desirable. Please share and RT. efzu.fa.em2.oraclecloud.com/hcmUI/Candid...
efzu.fa.em2.oraclecloud.com
Postdoc in Bond Decompositions of Chemical Simulations - DTU Chemistry
Postdoctoral position within a new long-term project funded by the Novo Nordisk Foundation concerned with the development of novel machine learning methods for inferring chemical properties inherent t...
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Janus Juul Eriksen @januseriksen.bsky.social · 26/08/2026
Nice and the living report looks very well done.
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Janus Juul Eriksen @januseriksen.bsky.social · 25/08/2026
What's the status on use with (GPU4-)PySCF?
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Janus Juul Eriksen @januseriksen.bsky.social · 05/03/2026
Now out in JCTC: pubs.acs.org/doi/full/10....
pubs.acs.org
Solvation Lies Within: Simulating Condensed-Phase Properties from Local Electronic Structures
In transitions between different environmental settings, a molecular system inevitably undergoes a range of detectable changes, and the ability to accurately simulate such responses, e.g., in the form of shifts to molecular energies, remains an important challenge across physical chemistry. Based on an exact decomposition of total energies from Kohn–Sham density functional theory in a basis of spatially localized molecular orbitals, the present work outlines a robust protocol for sampling the effect of solvation within homogeneous condensed phases by focusing on perturbations to local electronic structures only. We report chemically intuitive results for binding energies of water, ethanol, and acetonitrile that all display fast convergence with respect to the bulk size. Results stay largely invariant with respect to the choice of basis set while reflecting differences in density functional approximations, and our protocol thus allows for a physically sound and efficient estimation of general effects related to bulk solvation.
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Janus Juul Eriksen @januseriksen.bsky.social · 16/01/2026
On my end, thanks to @villumfonden.bsky.social, @novo-nordisk.bsky.social, and the Independent Research Fund Denmark for generous funding.
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Janus Juul Eriksen @januseriksen.bsky.social · 16/01/2026
We believe our protocol will allow for a physically sound and efficient estimation of general effects related to bulk solvation, and we're currently working on extensions to heterogeneous system (in terms of solvation free energies) as well as applications beyond ground-state properties.
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Janus Juul Eriksen @januseriksen.bsky.social · 16/01/2026
Our study reports chemically intuitive results for binding energies of water, ethanol, and acetonitrile that all display fast convergence with respect to the bulk size (here shown for the case of liquid water).
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Janus Juul Eriksen @januseriksen.bsky.social · 16/01/2026
Our work thus enables a focus on perturbations to local electronic structures only, e.g., that of a central monomer, and we show how results naturally generalize from simple dimer models to extended bulks.
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Janus Juul Eriksen @januseriksen.bsky.social · 16/01/2026
This is made possible by means of an exact decomposition of total energies from Kohn–Sham density functional theory into corresponding monomer energies, operating in a basis of spatially localized molecular orbitals.
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Janus Juul Eriksen @januseriksen.bsky.social · 16/01/2026
In collaboration with Filippo Lipparini in Pisa, we have just published a new preprint detailing a robust protocol for computing binding energies of individual monomers suspended in homogeneous condensed phases: arxiv.org/abs/2601.08649
arxiv.org
Solvation Lies Within: Simulating Condensed-Phase Properties from Local Electronic Structures
In transitions between different environmental settings, a molecular system inevitably undergoes a range of detectable changes, and the ability to accurately simulate such responses, e.g., in the form...
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Reposted by Janus Juul Eriksen
arXiv physics.chem-ph Chemical Physics @physicschemph-bot.bsky.social · 14/01/2026
Kasper F. Schaltz, Jonas Greiner, Filippo Lipparini, Janus J. Eriksen: Solvation Lies Within: Simulating Condensed-Phase Properties from Local Electronic Structures arxiv.org/abs/2601.08649 arxiv.org/pdf/2601.08649 arxiv.org/html/2601.08649
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Janus Juul Eriksen @januseriksen.bsky.social · 13/01/2026
Now out in @acs.org JCTC: pubs.acs.org/doi/full/10....
pubs.acs.org
A Reusable Library for Second-Order Orbital Optimization Using the Trust Region Method
We present a reusable, open-source software implementation of the second-order trust region algorithm in the new OpenTrustRegion library. We apply the implementation to the general-purpose optimizatio...
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Janus Juul Eriksen @januseriksen.bsky.social · 28/11/2025
Found a few typos. Where to report? 😜
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Janus Juul Eriksen @januseriksen.bsky.social · 07/11/2025
New v2.0.0 of OpenTrustRegion now released. Please see the changelog for an account of all of the major changes: github.com/eriksen-lab/...
github.com
Release OpenTrustRegion v2.0.0 release · eriksen-lab/opentrustregion
Changelog Release includes PRs 12, 14, 15, 16, 19, 21, 22, 23, 24, 25, 26 Interface breaking changes Centralized settings objects — PR 21: Centralized Settings Types for Solver and Stability Che...
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Reposted by Janus Juul Eriksen
Dagbladet Information @information.dk · 04/09/2025
Regeringen har ikke fundet midler til at sikre det digitale opslagsværk Den Danske Ordbog. »I en tid, hvor fakta er til forhandling, og hvor kunstig intelligens gør det sværere at skelne sandt fra falsk, er der akut brug for troværdige, offentligt tilgængelige opslagsværker,« skriver Rasmus Elmelund
information.dk
Hovedløst ikke at sikre Den Danske Ordbog
I en tid, hvor AI gør det sværere at skelne sandt fra falsk, er der akut brug for troværdige, offentligt tilgængelige opslagsværker. Det er uforståeligt, at Den Danske Ordbog er lukningstruet
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Reposted by Janus Juul Eriksen
Cecilie Bjerre @cbjerre.bsky.social · 22/09/2025
I Det Unge Akademi har vi skrevet en ønskeseddel til årets forhandlinger af forskningsreserven. Læs med her: www.altinget.dk/forskning/ar...
altinget.dk
Det Unge Akademi: Her er vores fire ønsker til årets forskningsreserve - Altinget
Den frie forskning svækkes, hvis politiske dagsordener styrer midlerne. Der er brug for rolige rammer, langsigtet vision og reelt frie midler. Ellers mister vi fremtidens gennembrud, innovation og vid...
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Reposted by Janus Juul Eriksen
Jan H. Jensen @janhjensen.bsky.social · 18/09/2025
#compchem
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Reposted by Janus Juul Eriksen
Hugh Burton @hughburton.com · 18/09/2025
Our first @uclchemistry.bsky.social paper is now out in @pubs.acs.org... Take a look for new advances in low-spin ROHF theory for complex spin coupling! #CompChem pubs.acs.org/doi/10.1021/...
pubs.acs.org
Geometric Direct Minimization for Low-Spin Restricted Open-Shell Hartree–Fock Theory
It has recently been shown that configuration state functions (CSFs) with local orbitals can provide a compact reference state for low-spin open-shell electronic structures, such as antiferromagnetic ...
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Reposted by Janus Juul Eriksen
Cecilie Bjerre @cbjerre.bsky.social · 18/09/2025
Sammen med Thomas, @kristinabsimonsen.bsky.social og @panktroels.bsky.social fra Det Unge Akademi har jeg skrevet et debatindlæg i @politiken.dk om regeringens “åndelige oprustning” og de samtidige nedskæringer i den kulturelle infrastruktur. Læs med her: politiken.dk/debat/debati...
politiken.dk
Lektorer og adjunkt: Der er lang vej til åndelig oprustning, når regeringen undergraver landets kulturelle infrastruktur
Kulturarvsinstitutioner som Den Danske Ordbog, Rigsarkivet og Det Kongelige Bibliotek er ikke luksus – de er fundamentet for vores fælles hukommelse og evne til at tænke kritisk.
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Janus Juul Eriksen @januseriksen.bsky.social · 18/09/2025
Code: github.com/eriksen-lab/... On my end, thanks to @villumfonden.bsky.social & Independent Research Fund Denmark for generous funding.
github.com
GitHub - eriksen-lab/opentrustregion: A Reusable Library for Second-Order Trust Region Orbital Optimization
A Reusable Library for Second-Order Trust Region Orbital Optimization - eriksen-lab/opentrustregion
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Janus Juul Eriksen @januseriksen.bsky.social · 18/09/2025
As such, we believe our work on the OpenTrustRegion library has massive potential in making genuine and robust second-order methods widely applicable throughout our community. This is the first paper in a new Nordic collaboration with @idamaho.bsky.social & Susi Lehtola. More to come!
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Janus Juul Eriksen @januseriksen.bsky.social · 18/09/2025
Our permissibly licensed implementation can be included within both free and open-source, academically licensed closed-source, and commercial software packages. In the study, we present examples of interfaces to three different codes, and we bid future interfaces and extensions most welcome.
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Janus Juul Eriksen @januseriksen.bsky.social · 18/09/2025
To that end, our implementation guarantees robust convergence onto a local minimum in both SCF calculations and other types of applications, and we demonstrate the difference in speed to conventional methods to be negligible, even for relatively simple systems.
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Janus Juul Eriksen @januseriksen.bsky.social · 18/09/2025
In our opinion, the risk of false convergences onto saddle points in applications of HF and KS-DFT is undeniably real for first-order (and even many second-order) solvers to all but the most simple of molecular systems. These can only be safely avoided by employing robust second-order optimization.
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Janus Juul Eriksen @januseriksen.bsky.social · 18/09/2025
As examples, our study presents applications to ground-state self-consistent field (SCF) calculations as well as the spatial localization and symmetrization of molecular orbitals, and we further highlight a variety of other interesting use cases towards the end.
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Janus Juul Eriksen @januseriksen.bsky.social · 18/09/2025
The OpenTrustRegion library is designed with an intention to be more versatile, more robust, and more reusable than any previously reported implementation of the second-order trust region method for general electronic-structure calculations.
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Janus Juul Eriksen @januseriksen.bsky.social · 18/09/2025
New preprint online today - spearheaded by my very talented postdoc, Jonas - on a new reusable, open-source software implementation of the second-order trust region algorithm: arxiv.org/abs/2509.13931 Here are some of the reasons why this library may be useful for a great many in our community. 👇
arxiv.org
A Reusable Library for Second-Order Orbital Optimization Using the Trust Region Method
We present a reusable, open-source software implementation of the second-order trust region algorithm in the new OpenTrustRegion library. We apply the implementation to the general-purpose optimizatio...
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Reposted by Janus Juul Eriksen
Christoph Dellago @chhdellago.bsky.social · 12/09/2025
Which five papers have most inspired you scientifically? Here is Michele Parrinello's answer (in no particular order): 1.) A. Rahman, "Correlations in the Motion of Atoms in Liquid Argon", Phys. Rev. 136, A405 (1964). doi.org/10.1103/Phys... 1/5
doi.org
Correlations in the Motion of Atoms in Liquid Argon
A system of 864 particles interacting with a Lennard-Jones potential and obeying classical equations of motion has been studied on a digital computer (CDC 3600) to simulate molecular dynamics in liqui...
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Janus Juul Eriksen @januseriksen.bsky.social · 04/09/2025
🚨 10 days left until deadline (14 Sept) 🚨
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Janus Juul Eriksen @januseriksen.bsky.social · 27/08/2025
Et forsøg på åndsrustbekæmpelse. Regeringen melder i dag ud, at den vil afsætte 68 mio. kr. til at styrke tysk og fransk på landets videregående uddannelser: ufm.dk/aktuelt/pres...
ufm.dk
Regeringen vil investere 68 mio. kr. i tysk og fransk på de videregående uddannelser
Interessen for sproguddannelser er faldet drastisk. Det er vigtigt, at vi i fremtiden har såvel undervisere, forskningsmiljøer og ansatte i erhvervslivet, der kan begå sig på andet end engelsk. Regeri...
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Reposted by Janus Juul Eriksen
Patrick @qmechanic.bsky.social · 26/08/2025
After a long time in the making I am happy that this piece of work finally sees the light of day: Fault-tolerant vibrational structure calculations arxiv.org/abs/2508.16253 #compchem #compchemsky #quantum #quantumcomputing
arxiv.org
Fault-tolerant quantum computations of vibrational wave functions
Quantum computation of vibrational properties of molecules is a promising platform to obtain computational advantages for computational chemistry. However, fault-tolerant quantum computations of vibra...
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Janus Juul Eriksen @januseriksen.bsky.social · 21/08/2025
The call is now live. Please see this thread for further information: bsky.app/profile/janu...
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Janus Juul Eriksen @januseriksen.bsky.social · 21/08/2025
The call is now live. Please see this thread for further information: bsky.app/profile/janu...
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Janus Juul Eriksen @januseriksen.bsky.social · 21/08/2025
Please see the official call for more information. In case you have specific questions related to the position or research theme, then write me directly: janus [at] dtu [dot] dk.
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Janus Juul Eriksen @januseriksen.bsky.social · 21/08/2025
The call for the first 2y postdoc position on this new project with a start by early 2026 (Jan/Feb) is now live: efzu.fa.em2.oraclecloud.com/hcmUI/Candid... Please share & repost. Deadline is 14 Sept. Copenhagen is a truly wonderful place to live and we offer excellent terms of employment at DTU.
efzu.fa.em2.oraclecloud.com
Postdoc in Bond Decompositions of Chemical Simulations - DTU Chemistry
Postdoctoral position within a new long-term project funded by the Novo Nordisk Foundation concerned with the development of novel computational methods for simulating chemical properties inherent to ...
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Reposted by Janus Juul Eriksen
Chemjobber @chemjobber.bsky.social · 20/08/2025
#chempostdoc #chemsky 🧪⚗️
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Reposted by Janus Juul Eriksen
Patrick @qmechanic.bsky.social · 18/08/2025
Interesting opportunity for young scientists with an excellent PI: bsky.app/profile/janu... #CompChemSky #compchem #EUChemJobs #ChemJobs
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Janus Juul Eriksen @januseriksen.bsky.social · 18/08/2025
The ideal candidate for the position is a driven early-career scientist with a deep and genuine interest in seeking to better influence and complement chemical synthesis by inferring mechanistic details and reaction rules.
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Janus Juul Eriksen @januseriksen.bsky.social · 18/08/2025
I will soon advertise a call for a 2y-postdoc position in my group intended for a talented, motivated, and ambitious candidate to help develop new ways to promote bonds as kernels in the interpretation of chemical simulations.
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Janus Juul Eriksen @januseriksen.bsky.social · 18/08/2025
The BONDS project will revolve around the development of new decompositions of molecular properties into local contributions that can provide key insight into the role of individual functional groups and the bonds that link these.
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Janus Juul Eriksen @januseriksen.bsky.social · 18/08/2025
Very excited to announce that I’ve been awarded a research grant from the Novo Nordisk Foundation of 10M DKK (1.34M EUR) under the New Exploratory Research and Discovery (NERD) programme to work on a new 5y electronic-structure project beginning by early-2026. novonordiskfonden.dk/bevillingsli...
novonordiskfonden.dk
List of grant recipients – Novo Nordisk Fonden
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Reposted by Janus Juul Eriksen
Janus Juul Eriksen @januseriksen.bsky.social · 31/07/2025
Fra @theyoungacademydk.bsky.social har @kristinabsimonsen.bsky.social, Alexandra Jønsson og jeg i dag en længere kronik i @information.dk om åndsrust og udhulningen af humaniora og samfundsvidenskaberne her til lands: www.information.dk/debat/2025/0...
information.dk
Åndelig oprustning begynder med anerkendelsen af årtiers forsømmelse af dansk humaniora
Vi kan ikke komme den nuværende åndsrust til livs uden fra politisk side at erkende, at vi i sandhed befinder os ved en europæisk skillevej
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Janus Juul Eriksen @januseriksen.bsky.social · 31/07/2025
Fra @theyoungacademydk.bsky.social har @kristinabsimonsen.bsky.social, Alexandra Jønsson og jeg i dag en længere kronik i @information.dk om åndsrust og udhulningen af humaniora og samfundsvidenskaberne her til lands: www.information.dk/debat/2025/0...
information.dk
Åndelig oprustning begynder med anerkendelsen af årtiers forsømmelse af dansk humaniora
Vi kan ikke komme den nuværende åndsrust til livs uden fra politisk side at erkende, at vi i sandhed befinder os ved en europæisk skillevej
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Reposted by Janus Juul Eriksen
Kristina Bakkær Simonsen @kristinabsimonsen.bsky.social · 31/07/2025
Med @januseriksen.bsky.social og Alexandra Brandt Ryborg Jønsson fra @theyoungacademydk.bsky.social 👇🏼
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Reposted by Janus Juul Eriksen
The Young Academy of Denmark @theyoungacademydk.bsky.social · 31/07/2025
Vigtig kronik i dagens @information.dk fra DUAs forperson, @januseriksen.bsky.social, næstforperson, Alex, og repræsentanten for vores forskningspolitiske udvalg, @kristinabsimonsen.bsky.social.
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Janus Juul Eriksen @januseriksen.bsky.social · 18/07/2025
Very nice wine! Only had half a glass once (different vintage, but still).
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Reposted by Janus Juul Eriksen
Janus Juul Eriksen @januseriksen.bsky.social · 08/07/2025
Sammen med @aaaautzen.bsky.social & @kristinabsimonsen.bsky.social har vi skrevet et indlæg i dagens @politiken.dk om den sindssyge nye kontanthjælpsreform og nogle af de konsekvenser, denne ender med at have for forskere m.fl. politiken.dk/debat/debati...
politiken.dk
Ane Halsboe-Jørgensen, du har altså en underlig måde at sige tak på
Som forskere tog vi ud for at bringe viden hjem til Danmark. Nu får vi og vores børn en dårligere retsstilling.
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