Scientists from IFW Dresden teamed up with colleagues from over 30 universities and institutes to investigate to what extent quantum simulations of material properties agree when they are performed with different software, independently coded. Thanks to an online collaboration, they successfully demonstrated that the most recent generations of codes agree well, in contrast to earlier generations. Their study has been published in Science (issue published 25 March 2016).
Reproducibility does not come easily
It's a corner stone of science: independent yet identical experiments should produce the same results. Only in this way can science identify ‘laws’, which lead to new insight and sometimes to new technologies. However, several recent studies have pointed out that such reproducibility does not always come spontaneously.
In scientific areas as diverse as psychology research and genetic research, cases were identified where repeating previous experiments led to very different results. Even predictions by computer codes require caution, since the way in which theoretical models are implemented may affect simulation results. This is a reason for concern in any field of research that critically depends on computer simulations.
For the study and design of materials, for instance, there are several independently coded software packages available based on quantum physics. They are moreover being used increasingly often in automated procedures with limited human supervision. It is therefore essential to know to what extent predicted materials properties depend on the code that has been used.
Online collaboration brings experts together
Despite the need for reliable property predictions of materials, the reproducibility of quantum simulations had not been investigated systematically before. This is mainly because there is no single person sufficiently skilled in all existing codes. Scientists from IFW Dresden therefore joined forces with more than 60 colleagues, bringing together the know-how of over 30 prominent institutions.
The researchers investigated 40 different methods to describe the influence of pressure in 71 different crystals. Due to the highly international composition of the team, discussions and collaboration were mainly conducted via online tools – similarly to the way people collaborate to write Wikipedia.
The team can now demonstrate that, although a few of the older methods clearly yield deviating results, predictions by recent codes are equivalent. This includes a method with about 600,000 lines of code developed at IFW Dresden (http://www.fplo.de/).
Moreover, the authors define a quality criterion that allows the verification of future software developments against their extensive database. New test data are continuously added to a publicly available website (http://molmod.ugent.be/DeltaCodesDFT). The researchers involved hope that their work will contribute to higher standards for materials property simulations, and that it will facilitate the development of improved simulation codes and methods.
Dr. Manuel Richter
Institute for Theoretical Solid State Physics at IFW Dresden
Dr. Carola Langer | idw - Informationsdienst Wissenschaft
Getting closer to porous, light-responsive materials
26.07.2017 | Kyoto University
25.07.2017 | Vanderbilt University
Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers
Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...
Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.
At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
26.07.2017 | Event News
21.07.2017 | Event News
19.07.2017 | Event News
26.07.2017 | Physics and Astronomy
26.07.2017 | Life Sciences
26.07.2017 | Earth Sciences