Finished: slowdown in production due to sudden policy changes of our host

This year 2023 has been particularly difficult due to lack of public funding in the Czech Republic.

Now, the policy of the HiLASE Centre is unfortunately turning to private solutions for its IT structure, therefore our group is anticipating a fall-back to the CESNET (MetaCentrum) infrastructure to achieve small and diverse tasks.

Our large computational tasks remain attributed to IT4I, with a framework that does extraordinarily well for our needs.

The CESNET and IT4I infrastructures are free of charge for the Institute of Physics and for the Academy of Sciences, while private solution (such as Microsoft Azure, Amazon Web Services, …) must be paid instead of people using the hardly acquired funding.

These changes seemingly enforced by our hierarchy will induce a slowdown in production of scientific results for several months (notably on TDDFT and DFTB production).

EDIT of Dec 4th 2023: the political storm has now ended. We are back to normal situation.

Funding extended by 1 year

The SLA department that hosts our research group has obtained a joint project OPJAK (Ministry of Research) in collaboration with several groups of the Institute of Physics (AS CR).

Our group is therefore prolonged by 1 year up to 2 FTE, counting 1 FTE for Dr. TJY Derrien, 0.5 FTE for Krystof Hlinomaz and 0.5 FTE for Kristyna Gazdova, effective from January 1st.

Krystof is planned to spend 0.5 FTE at TopTec (Turnov) and Kristyna has equivalent PhD contract in Brno.

Due to lack of visibility. The contracts will be for 1 year for now.

We contributed to the 7th IT4I users meeting

TJY Derrien, head of the computational group of Ultrafast Photonics at HiLASE, attended the 7th IT4I supercomputer users meeting. The annual workshop is excellent to meet with colleagues from best computational groups of the country from IOCB, FZU, CEITEC Brno, CATRIN Olomouc, Institute of Plasma Physics, ELI beamlines, IT4I, and more.

There, TJYD delivered an oral presentation titled „Benchmark of time-dependent density functional theory simulations on a variety of European CPU-based supercomputers“. In this communication, he presented a summary of the predictions obtained using quantum numerical simulations (time-dependent density functional theory, TDDFT) along with an overview of high performance computation analyses gathered since 2016 on a variety of CPU-based super-computers.

He also attended the meeting with the Users Council as secretary and chaired the 2 sessions of presentations of Tuesday.

The IT4I center has been the main working tool of our computational group since 2019 and has been strategic for contributing to high impact factor studies with our collaborators.

7th IT4I Users meeting attendees in the super-computing room
Credits: IT4I

National conferences matter: Laser63 in Třešt’.

On Oct. 18th-20th 2023, TJY Derrien, head of the group of Ultrafast Photonics, has participated and gave an oral presentation at the Laser63 conference, a Czech conference organized by the Czech Academy of Sciences, that gathers Czech scientists and laser industrial ecosystem from the Czech Republic.

Beyond the language barrier, it was very appreciable to meet new collaborators and very important for enabling further sustainability to deliver a summary on our capacity to prepare predictive numerical simulations for fs and ps laser interaction with materials.

Credits: HiLASE Centre

The press releases prepared by HiLASE are here: website | LinkedIn.

The website of the Czech conference Laser63 is here (in Czech).

Our TDDFT predictions are supporting tabletop attosecond spectroscopy experiments of the Charles University

Today, a new joint paper with the team of Martin Kozak of the Charles University was submitted for publication. The paper draft is available here and demonstrates an extraordinary agreement obtained between the harmonics generated from a silicon target irradiated with temporally-overlapping ultrashort laser pulses with the predictions prepared using the time-dependent density functional theory (TDDFT).

The paper suggests that the TDDFT simulation technique is sufficiently mature for making high-precision predictions for ultrashort laser processing and beyond.

Invited stay at the Instituto de Optica, CSIC, Madrid

Invited stay at the CSIC Madrid

TJY Derrien, leader of the Ultrafast Photonics group, was invited in the frame of CSIC-ILINK project for a duration of two weeks at the Instituto de Optica, CSIC, Madrid, Spain.

During this stay of 2 weeks in company of Prof. Javier Solis, Prof. Jan Siegel, Dr. Jörn Bonse, and Dr. Mario Garcia-Lechuga (project host), fruitful and exciting collaboration was initiated in view of preparation of a future joint funding.

During his visit, TJY Derrien gave seminar at the Instituto de Optica on Thu 5th of October, along with Prof. Jörn Bonse. Abstracts are available here.

LIPSS workshop

During the stay, the LIPSS workshop was also organized by Prof. Esther Rebollar and co-organizers.

We warmly thank our hosts for this wonderful hosting time and look forward to the next steps together!

We were granted 15 M. core-hours with the 29th IT4I-OPEN call

Today, the group of Ultrafast Photonics was granted with 15 millions core-hours for the preparation of quantum simulations based on the method of time-dependent density functional theory.

This computational time will be essentially meant to run the Octopus code (TDDFT) in collaboration with Prof. François Courvoisier (FemtoST, Besançon, France) and Dr. Peter Juergens (Max Born Institute, Berlin, Germany).

Another collaboration with CSIC Madrid has also started around TDDFT and will also be part of this project.

Visitors of the Marie Curie RISE “ATLANTIC” networking action are also entitled to get computational during their visit.

While great science lies ahead, we also hope to fetch funding for improving our people’s conditions very soon.

“Talent 2023” Czech competition high-school student Filip Neubauer stayed in our group two weeks

Czech Republic is organizing lots of opportunities for young talents. The Talent competition is one of them.

During two weeks, Filip Neubauer (from the high school of Stepanska, Praha) joined the group and had possibility to work on some of our datasets using machine learning.

It was great to interact with one of the new talents of this country and hope to see Filip coming back to us very soon!

Prof. Kazuhiro Yabana visited us at the HiLASE Centre

On September 18th 2023, we received the visit of Prof. Kazuhiro Yabana from the Institute of Computational Sciences, University of Tsukuba, Japan.

The visit started with an overview of the Hilase Centre activities, introduced by Sanin Zulić, International Business Development Manager of HiLASE.

Prof. Yabana then presented a seminar titled “Time-dependent density functional theory for extremely nonlinear optics”, where features of the massively parallel simulation code “SALMON” was presented.

The talk was followed by an overview of activities of the department of Scientific Laser Applications (SLA) by Prof. Nadezhda M. Bulgakova, leader of the SLA department.

It was supplemented by a presentation of the quantum simulation activities of the Hilase Centre by Dr. Thibault JY Derrien, leader of the group of Ultrafast Photonics,

The visit was concluded by a tour of the femtosecond laboratory of the SLA department.

Prof. Yabana and the Hilase Centre are members of the Marie Curie Research and Innovation Staff Exchange “ATLANTIC” network.

(Website of the Marie Curie RISE network “ATLANTIC”) (in English).

(Prof. Yabana, member of the “ATLANTIC” project) (in Japanese).

Our experience with machines

Our usage of high performance computers, mostly machines of the Top500 charts, started in 2008.

  1. Since 2019: Top500 Karolina (, thanks to IT4I-OPEN calls
  2. 2023: Sunrise (ELI beamlines, Czech Republic)
  3. 2022: Eclipse (ELI beamlines, Czech Republic)
  4. 2020 – 2023: Navigator (University of Cumbria, Portugal) thanks to PRACE DECI calls
  5. 2019: Barbora (, thanks to IT4I-OPEN calls
  6. 2016: Top500 Salomon (, thanks to IT4I-OPEN calls
  7. 2019 – 2020: Top500 Prometheus (Cyfronet, Poland) thanks to PRACE DECI calls
  8. 2018 – 2019: first user of Top500 Draco (MPCDF, Germany)
  9. 2016 – 2018: Top500 EOS (Fritz Haber Institute, Germany)
  10. 2010 – 2012: Top500 Jade (, France)

Since 2016, our main usage is to run the Octopus TDDFT simulation code for preparing predictions of light interaction with solid materials.