Hotel Jäger von Fall, Lenggries, Bavaria, Germany
Organizers: Harald Oberhofer, Johannes Margraf
Webpage: http://macsims.ch.tum.de

Multi-scale simulation approaches rely on a hierarchy of increasingly accurate and highly resolved methods to capture the different time- and length-scales relevant to a process of
interest. Traditionally, this might involve coupling classical molecular dynamics with electronic structure calculations (QM/MM), or embedding a quantum mechanical system in a point charge
or continuum environment. In this context, the models comprising the individual layers of the multi-scale hierarchy are often unrelated. For instance, the empirical potential and DFT method in a QM/MM simulation are independently defined at the beginning of the simulation. Enormous advances in electronic structure algorithms and hardware now allow first principles calculations to be carried out on a truly massive scale. This leads to a novel perspective of multi-scale models: electronic structure data can be generated with high enough quality and quantity to allow the application of coarse graining and machine learning techniques. Instead of defining
separate physical models at different scales, the electronic structure method directly informs the next layer of the multi-scale hierarchy. The goal of this workshop was to bridge the gap between
traditional, layered multi-scale techniques and the more direct coarse graining and machine learning approaches to the simulation of extended systems, thereby bringing together researchers working on QM/MM or other embedding techniques with those who apply coarse graining and interpolation to electronic structure data in different contexts (e.g. potential energy surfaces, electronic properties, charge transport, rate constants in catalysis) and with different methods (neural networks, Gaussian process regression, kernel ridge regression, splining, etc).

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Organisers: Michele Ceriotti, Tom Markland, Jeremy Richardson and Mariana Rossi

Dates: 25 -29 June, 2018

We convened a School on Path Integral Quantum Mechanics at the CECAM headquarters in Lausanne, Switzerland. The school gathered together 17 speakers (11 invited and 6 contributed) and 46 participants affiliated with 15 different countries. We
received a total of 85 applications to attend the school and unfortunately could not accept more participants due to space constraints in the lecture room. This amount of applications, only two years after we had the last school on the same topic, underlines
the growth of the community performing research on the theory and practice of Path Integral (PI) techniques for the atomic-scale modelling of the quantum behavior of materials and molecules.

As in the last school, we explicitly asked the speakers to prepare pedagogic talks aimed at introducing the participants to the methods and simulation techniques to treat imaginary and real time path integrals, for both adiabatic and non-adiabatic dynamics.
Invited and contributed speakers were encouraged to give lectures that explained the methods in great detail, so that the students could benefit the most from the school, even if this was their first contact with path integral methods.

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October 8, 2018 to October 12, 2018
Location: CECAM-HQ-EPFL, Lausanne.

The aim of the school was to give a deep introduction on the theoretical and practical aspects of the electronic excitations, which are probed by experimental techniques such as optical absorption, EELS and photo-emission (direct or inverse). From the theory point of view, excitations and excited state properties are out of the reach of density-functional theory (DFT), which is a ground-state theory. In the last thirty years, other ab-initio theories and frameworks, which are able to describe electronic excitations and spectroscopy, have become more and more used: time-dependent density-functional theory (TDDFT) and many-body perturbation theory (MBPT) or Green’s function theory (GW approximation and Bethe-Salpeter equation BSE). In fact, computational solutions and codes have been developed in order to implement these theories and to provide tools to calculate excited state properties. The present school focused on these points, covering theoretical, practical, and also numerical aspects of TDDFT and MBPT, non-linear reponse and real-time spectroscopies. Finally, a large part of the school was devoted to the codes implementing such theories (ABINIT, 2Light, Lumen, DP, EXC).

Continue reading Theoretical Spectroscopy Lectures →

The 23rd ETSF Workshop on Electronic Excitations
Interdisciplinary views on quantum many-body theory
The University of Milan, Italy, September 10 – 14, 2018

The 2018 edition of the European Theoretical Spectroscopy Facility (ETSF) Workshop on Electronic Excitations has been dedicated at fostering the cross-fertilization between different approaches to many-body phenomena, transcending the traditional barriers between disciplines. The workshop therefore brought together experts facing similar problems from different perspectives, for different applications, and often with a different language. Besides discussing application of many-body theories to excitations in condensed matter, i.e. the traditional field of expertise of ETSF, topics covered by the workshop included nuclear physics, quantum chemistry, ultrafast excitation dynamics, quantum transport, topological insulators and novel algorithmic approaches to many-body problems inspired by machine learning and data science.

Continue reading 23rd ETSF Workshop on Electronic Excitations: Interdisciplinary views on quantum many-body theory →

The 17th International Conference on Density-Functional Theory and its Applications (DFT2017) took place in Tällberg, Sweden, in August 2017. The conference belongs to a series of biennial meetings, which have taken place in Paris (1995), Vienna (1997), Rome (1999), Madrid (2001), Brussels (2003), Geneva (2005), Amsterdam (2007), Lyon (2009), Athens (2011), Durham (2013), Debrecen (2015) and Tällberg (2017). DFT2017 covered a wide range of topics related with density functional theory. It brought together the foremost researchers from all around the world working on the development of the theory, extensions to new fields and providing a broad range of fascinating applications.

Conference Webpage: 

https://www.dft2017.conf.kth.se/

Chair:

Prof. Dr. Levente Vitos, KTH Stockholm, Sweden

Organizers:

Prof. Dr. Olle Eriksson, Uppsala University, Sweden
Prof. Dr. Börje Johansson, KTH Stockholm, Sweden
Dr. Xiaoqing Li, Uppsala University, Sweden
Doc. Stephan Schönecker, KTH Stockholm, Sweden
Prof. Dr. Levente Vitos, KTH Stockholm, Sweden

International Scientific Committee:

Prof. Dr. Henry Chermette, Universite de Lyon, France
Prof. Dr. Claude A. Daul, University of Fribourg, Switzerland
Prof. Dr. Jose M. Garcia de la Vega, Universidad Autonoma de Madrid, Spain
Prof. Dr. Paul Geerlings, Vrije Universiteit Brussel, Belgium
Prof. Dr. Paola Gori-Giorgi, Vrije Universiteit Amsterdam, Netherlands
Prof. Dr. Miguel A. L. Marques, Martin-Luther-University Halle-Wittenberg, Germany
Prof. Dr. Ágnes Nagy, University of Debrecen, Hungary
Prof. Dr. Dennis R. Salahub, University of Calgary, Canada
Prof. Dr. Karlheinz Schwarz, Vienna University of Technology, Austria
Prof. Dr. David J. Tozer, University of Durham, United Kingdom
Prof. Dr. Levente Vitos, KTH Stockholm, Sweden

 

Description and summary:

In 2017, the broadest international meeting on DFT was organized for the first time in Scandinavia. Fifty three years passed since the fundamental theorems behind one of the most successful quantum theory of inhomogeneous electron gas were put forward. Already in its original form, DFT was suitable to explain a series of phenomena related to simple molecules and solids. It took nearly a quarter of century when it became robust enough to account for the magnetic ground state of a chunk of single crystal iron. More than a decade of future research was required in order to extend the scope of DFT to complex high-technology materials. Continue reading Scientific report on the 17th International Conference on Density-Functional Theory and its Applications →

CECAM Qubit_Abstract book

ProgramQubits

Organizers: Adam Gali (Budapest), Thomas Frauenheim (Bremen), Jörg Wrachtrup (Stuttgart)

Venue: University of Bremen, Bremen Center for Computational Materials Science (BCCMS), Germany, 9th until 13th of July 2018

Sponsors: University of Bremen (BCCMS), Psi-k, DFG

https://www.bccms.uni-bremen.de/veranstaltungen/2018/cecam-qubit/

Point defects acting as color centers in solids may realize single photon source and quantum bits that can be harnessed in quantum information processing and nanoscale sensor applications which may revolutionize the info-communication technology, biological research and therapy. The leading contender is the nitrogenvacancy center in diamond which may be considered as a robust quantum tool. Several quantum algorithms and protocols for sensing have been already demonstrated by this center. However, researchers face many materials science problems in order to maintain the favorable intrinsic properties of this color center that can be perturbed by other defects either in bulk or at the surface of diamond that is difficult to resolve because of its chemical hardness and the concurrent stability of carbon allotropes.

Recently, theory-driven search for alternative materials could identify other quantum bit candidates in technologically mature wide band gap semiconductors, particularly silicon carbide, that have been recently demonstrated in experiments. However, the knowledge about these color centers is scarce and only the tight collaboration of experimental and atomistic simulation researchers would lead to a rapid progress in the field. The proposed workshop aims at bringing together world-leading experts in all these fields to improve interdisciplinary cooperation overcoming traditional boundaries between scientific disciplines.