All posts by Damian Jones

Member of the STFC Scientific Computing Department. Based at STFC Daresbury Laboratory, Warrington, UK.

CAMD Summer School 2018

The Psi-k sponsored “CAMD Summer School 2018 Electronic Structure Theory and Materials Design” took place in the week August 12-17, 2018 at Strandhotel Marienlyst in Helsingør, Denmark. Thanks to the more than 100 external attentive summer school students and the 15 very helpful invited lecturers, the school was the nice success that we had hoped for. The school taught PhD students from all over the world the basic and more advanced concepts in modern electronic structure theory including ground state density functional theory (DFT), many-body methods materials informatics and machine learning. Emphasis was put on the methodology applied “on-top” of ab-initio calculations which is essential for the computational design of new functional materials.

Read the full report here.

Report on the Psi-k/CECAM Research Conference “Ab initio Spin-Orbitronics”

September 25, 2017 – September 29, 2017
Hotel Promenade, Montesilvano, Pescara (Italy)

Organizers:
Silvia Picozzi (Consiglio Nazionale delle Ricerche CNR-SPIN, Italy)
Stefan Blügel (Forschungszentrum Jülich, Germany)
Ingrid Mertig (Martin Luther University Halle, Germany)

The main purpose of this Psi-k/CECAM research conference (with about 110 participants) has been to highlight the very recent theoretical and computational developments related to the interplay of spin-orbit interaction with electronic structure, magnetism, transport as well as its link to strongly correlated materials and ultrafast currents in diverse materials. We have focused on discussing spin-orbit coupling (SOC) as a means of engendering fundamentally novel physical phenomena in exotic systems. The Conference therefore spanned several research dimensions, ranging from Materials (in the form of bulk compounds, surfaces and interfaces, thin films and heterostructures) to Functionalities (associated with topology, spin-momentum locking, valley degrees of freedom, skyrmions, coupling to electric currents by Berry phases, etc.) to method developments (in terms of dynamical processes in out-of-equilibrium quantum matter, Berry phase physics, etc). A brainstorm about concepts and ideas in a little understood phenomenon, such as orbital magnetization, was carried out under the guidance of Prof. Ivo Souza. While the main focus was on ab initio simulations, a few leading scientists in experiments were invited (Prof. Stuart Parkin, Prof. Claudia Felser, etc) and a strong interface to many-body physics treated on the basis of realistic model Hamiltonians was included.

Read the full report here.

Modern Approaches to Coupling Scales in Materials Simulation

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).

Read the full report here.

CECAM/Marvel/Psi-k School on Path Integral Quantum Mechanics: From the Basics to the Latest Developments

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.

Read the full report here.

Alessandro De Vita

Dear friends,

Many of you will have heard by now the tragic news that our dearest friend and colleague Alessandro De Vita passed away on Tuesday afternoon. Sandro was killed in a motorbike accident while going to the airport. Commuting between Trieste and London, two most beloved cities for him, was part of his life – a life that he lived so fully.

We have received an outpouring of grief in the last two days that is a testament to how much loved he was, and how strong was his impact in the life of the people that met him – his sharp intelligence, his infinite knowledge, his surprising imagination, his unbridled talk, his mischievous and deeply generous spirit all stood out. And most of all, his passions in life – the friends, the science, the music, the poetry.

Psi-k and CECAM, to which Sandro gave so much, will think of public ways to celebrate him, and any suggestion would be most welcome. If you wanted to dedicate some of your thoughts to him, he would have had a few suggestions himself. Light a candle, somewhere. Say a prayer. Listen to Glenn Gould play the 25th Goldberg variation – he always said that it contained all the sorrow of the world.

We are all with you, Sandro – with Christine, with your family, with your friends.

Atque in perpetuum, frater, ave atque vale.

Psi-k and CECAM

https://www.cecam.org/devita.html

8th School and Workshop on Time-Dependent Density-Functional Theory: Prospects and Applications

August 20th-31st, 2018
Benasque Center for Science “Pedro Pascual”, Benasque, Spain

http://www.benasque.org/2018tddft/

Organizers: Angel Rubio, Eberhard K. U. Gross, Miguel A. L. Marques, Neepa Maitra, Alberto Castro

There are many alternative schemes to approach the time-dependent, out-of-equilibrium, many-electron problem. Time-dependent density-functional theory (TDDFT) has a significant “market share” due to the same reasons that make conventional ground state density-functional theory (DFT) a successful scheme: the fairly good predictive power at a moderate computational cost. As a consequence, its use has quickly grown, and its reliability for many purposes has been sanctioned by many applications and benchmarks over the years. As the computational resources increase, however, various alternatives such as advanced post-Hartree Fock multi-configuration schemes or many-body perturbation theory techniques can be applied to larger systems, and may provide more precise results. Newer and more intriguing possibilities, such as the direct solution of the many-electron Schrödinger equation with quantum computers, and the use of machine learning techniques for the prediction of many properties, appear also in the horizon. It is therefore necessary to review the capabilities and perspectives of TDDFT. This is the main goal of the Workshop, and of the School that we organized immediately before the Workshop.

This School+Workshop event is in fact a new iteration of a series dedicated to TDDFT, that started in 2004. It takes place every two years, a periodicity that we feel that is adequate to follow the advances in the topic. However, it always takes place in Europe, and there was a strong demand for a similar event taking place in the US, due to the difficulties in the travel, specially for students and young researchers. Fortunately, the demand was met in the last year by a similar event (a school on TDDFT followed by a workshop on first principles approaches to the electronic excited states problem) that took place in Telluride, Colorado. Part of the organizers of this event were also present in Benasque, and the goal is to periodically repeat the US event, also every two years if possible. It should be noted, also, that a similar event is being planned in Asia (Tsukuba, Japan), by Prof. K. Yabana.

You can read the full workshop report here.

Photoinduced Processes in Embedded Systems (PPES)

Organizers: Claudia Filippi (University of Twente, The Netherlands),  Filippo Lipparini (University of Pisa, Italy), Benedetta Mennucci (University of Pisa, Italy)

The scientific aim of the Psi-k workshop “Photoinduced Processes in Embedded Systems” was to bring together researchers from the physics, chemistry, and biophysics communities working on the computational study of photo-physical processes in complex systems. Modelling such phenomena is challenging since they involve very different space and time scales, from the extremely fast, localized absorption of light to the collective, slow motions of the environment.

The workshop has focused on some of the most recent theoretical and algorithmic developments in the field such as:

  • DFT embedding for excited states
  • Hybrid QM/Classical approaches
  • Highly-correlated methods for excited-state dynamics
  • TDDFT outside the Franck-Condon region
  • Non-adiabatic dynamics

These methodological aspects have been framed in the context of realistic applications to materials and biosystems such as:

  • Natural photosynthetic systems
  • Photo-induced signal transduction in bio-systems
  • Bio-mimetic light-driven molecular devices
  • Photo-induced charge propagation in solar-energy devices

You can read the full workshop report here.

Emergence of surface and interface structure from friction, fracture and deformation

The workshop on Emergence of surface and interface structure from friction, fracture and deformation , held at CECAM HQ in Lausanne from 24-27th July 2018, considered the topographic, morphological and chemical structure of surfaces and interfaces that arises from mechanical processes and how this structure affect the mechanical behaviour of materials but cannot typically be systematically controlled. As well as Psi-k, the workshop received support from CECAM, the DFG and EPSRC.

You can read the full workshop report here.

8th International ABINIT Developer Workshop

Initiated in 2002, the series of ABINIT developer workshops are organized every two years (Louvain-la-Neuve 2002, Paris 2004, Liège 2007, Autrans 2009, Han-sur-Lesse 2011, Dinard 2013, Liège 2015) and plays an important role in the life of the ABINIT community. It is the occasion for the most active ABINIT developers — as well as a few expert users — and selected invitees, to gather and exchange information, and present recent developments. The future of ABINIT is also discussed, and recommendations are issued.

The workshop in Fréjus followed the spirit of preceding workshops and was particularly fruitful. This year, the number of participants reached 39 people. Workshop program, abstract and oral presentations (pdf) are permanently available on the website of the conference (https://abidev2017.abinit.org/program) linked from
ABINIT website.

You can read the full workshop report here.