Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have developed a new procedure, enabling them to speed up elaborate computer simulations that analyze matter under extreme conditions. In particular, this work improves the evaluation of experiments at large-scale research facilities like the European XFEL – and should facilitate substantial progress, among others, in fusion research and laboratory astrophysics. The team is presenting its results in the journal npj Computational Materials (DOI: 10.1038/s41524-026-02088-9).
Sometimes, matter is present in extreme states – such as in stars or in the interior of gas giants where enormous pressures and temperatures prevail. Such conditions can also be produced in the lab, in laser fusion experiments, for instance. In order to understand precisely what happens, researchers use X-ray scattering – as at the European XFEL near Hamburg. It works on the principle that a high-intensity X-ray beam penetrates the sample; inferences about its properties can then be drawn from the resulting scattering signal. But the measured data are often not sufficient to unequivocally determine properties like density and temperature.
This is where computer simulations come in. They deliver theoretical models for interpreting the measured data. “We simulate the system with various parameters and look to see which combination corresponds to the experimental observation,” explains physicist Dr. Tobias Dornheim who has been head of the high energy density department in HZDR’s Institute of Radiation Physics since October 2025.
This is important in fields like the development of laser fusion. In this process, laser pulses compress and heat a small sphere of hydrogen to such an extent that the atomic nuclei fuse and release energy. The objective is to use these processes in future power plants – as a climate-friendly, almost inexhaustible source of energy. To achieve this, experts have to investigate and fully comprehend the underlying physical processes in extreme states of matter and to do this, in turn, it is essential to understand exactly what temperatures and pressures are actually present in the sample under scrutiny.
Simulations are key
In the past, simple models that were based on a series of approximations were often used to interpret measurement data. By contrast, the time-dependent density functional theory employed in the current work is very precise, which does, however, necessitate a vast amount of computing time. The problem is that at high temperatures, many quantum mechanical states have to be considered while, at the same time, numerical artifacts arise that can distort the results. In order to interpret their experiments, researchers have to calculate numerous combinations of temperature and density – which is known as a parameter scan. This requires a lot of computing time on supercomputers. “And we simply don’t have unlimited amounts of that,” says Dornheim.
This is where the new method comes into play. Instead of researchers constantly refining the simulations, the basic idea here is to systematically identify which elements of the signal calculated are physically relevant – and which are just numerical noise. At the heart of this approach is a mathematical transformation into so-called imaginary time. This is a concept derived from quantum mechanics that can also be investigated in actual experiments and is closely related to the temperature of the system studied (also see press release). “Building on this, we combine a reliable convergence test with a filtering procedure that removes artificial ringing without distorting the physical information,” explains Dornheim’s colleague, Dr. Zhandos Moldabekov who had the idea for the new method. The big advantage is that instead of simply smoothing out the data, which often obscures important details, the signal’s physical structure remains intact.
Up to 50 times faster
In practice, this results in massive acceleration. “In our tests, the simulations ran 50 times faster,” explains Moldabekov. Looking ahead, this means that instead of only being able to do a few simulations on expensive supercomputers, it will be possible to conduct comprehensive parameter studies and thus reliably evaluate the experimental data. The quality of the results is improved, too: the new method reduces systematic distortions while preserving fine structures in the spectrum that register important physical processes.
One of the main areas of application are experiments at the European XFEL, especially within the HIBEF consortium coordinated by HZDR. Here, researchers investigate matter under the type of extreme conditions that occur in laser fusion. “If we want to have a fusion power plant, we have to understand what really happens in such extreme states of matter,” Dornheim emphasizes. Now, our new method makes it possible to comprehensively and precisely analyze the datasets from such experiments.”
In addition, this approach opens up new prospects for laboratory astrophysics because the conditions that prevail in the deep interior of planets – that is, where matter is compressed under intense pressure and heated to extremely high temperatures – can be recreated. Other properties of materials, such as how well they conduct electricity or absorb radiation, can also be calculated more quickly and accurately using this method. “It should be possible to develop our method into a standard tool for interpreting modern X-ray experiments,” Moldabekov hopes. “In the future, it could play a central role in exploring extreme states of matter.”
Publication:
Z. Moldabekov, S. Schwalbe, U. H. Acosta, T. Gawne, J. Vorberger, M. Pavanello, T. Dornheim: Enhancing the Efficiency of Time-Dependent Density Functional Theory Calculations of Dynamic Response Properties, npj Computational Materials , 2026 (DOI: 10.1038/s41524-026-02088-9)
Additional information:
Dr. Tobias Dornheim
Institute of Radiation Physics at HZDR
Phone: +49 351 260 3634 | Email: t.dornheim@hzdr.de
Media contact:
Simon Schmitt | Head and Press Officer
Communications and Media Relations at HZDR
Phone: +49 351 260 3400 | Mobile: +49 175 874 2865 | Email: s.schmitt@hzdr.de
The Helmholtz-Zentrum Dresden-Rossendorf (HZDR) performs – as an independent German research center – research in the fields of energy, health, and matter. We focus on answering the following questions:
To help answer these research questions, HZDR operates large-scale facilities, which are also used by visiting researchers: the Ion Beam Center, the Dresden High Magnetic Field Laboratory and the ELBE Center for High-Power Radiation Sources.
HZDR is a member of the Helmholtz Association and has six sites (Dresden, Freiberg, Görlitz, Grenoble, Leipzig, Schenefeld near Hamburg) with almost 1,500 members of staff, of whom about 700 are scientists, including 200 Ph.D. candidates.
npj Computational Materials
Computational simulation/modeling
Not applicable
Enhancing the Efficiency of Time-Dependent Density Functional Theory Calculations of Dynamic Response Properties
25-Apr-2026