In this series, methods that have become fundamental tools in computational physics and chemistry are presented by their originators at a level appropriate for master and graduate students. The lectures are followed by an interview: we ask our guests to recall for us the period, problems, people and circumstances that accompanied the creation of milestone methods and algorithms that we now routinely use.

Join us to share this exciting opportunity to learn first-hand from our pioneers and get to know better the genesis of work that is now recorded in books!

Time-dependent density functional theory: past, present and future

Thursday September 28 2023, 18:00 CEST

Online + BCH 2103, EPFL. Zoom link https://epfl.zoom.us/j/62003705104?pwd=dGNsZndJclJlZWhpcUZOc0Vvdlpadz09

18:00 — Introduction
18:05 — TDDFT: from basic theorems to spectra to ultrafast dynamics (Eberhard K. U. Gross)
18:45 — TDDFT: from non-equilibrium phenomena to quantum materials engineering (Angel Rubio)
19:25 — Break
19:45 — Interview and recollections
20:30 — End

Time-dependent density functional theory: from basic theorems  to spectra to ultrafast dynamics

Eberhard K. U. Gross, Hebrew University of Jerusalem

In this lecture, time-dependent density functional theory (TDDFT) will be presented as a versatile and affordable method to deal with the dynamics of electronic systems. Earlier applications of TDDFT focused on the response to weak probes, thus providing a reliable description of spectroscopic data. In recent years, real-time TDDFT simulations of strongly driven systems have become increasingly popular to predict the dynamical behavior far from thermal equilibrium. We shall visualize the laser-induced formation and breaking of chemical bonds in real time, and we shall highlight non-steady-state features of the electronic current through nano-scale junctions. With the goal of pushing magnetic storage processes towards ever faster time scales, an optically induced spin transfer (OISTR) from one magnetic sub-lattice to another will be presented. The OISTR effect was first predicted in 2016 by TDDFT calculations and two years later confirmed in several experiments. The OISTR effect marks the birth of “atto-magnetism”. To use this and other quantum effects in real-world devices, one has to face the fact that quantum systems tend to lose their “quantumness” on a rather fast time scale. This effect, known as “decoherence”, has prevented to date the construction of scalable quantum computers. As a particular challenge for the future, we shall address the ab-initio description of decoherence.

Eberhard Gross received his PhD in Physics in 1980 at the University of Frankfurt, Germany. From Frankfurt he moved to the University of California, Santa Barbara, to join the group of Walter Kohn, first as a postdoc, then as a Heisenberg fellow. In 1990, he became a Fiebiger Professor at the University of Würzburg, Germany. From 2001 he had a Chair of Theoretical Physics at the Free University of Berlin, and from 2009 to 2019 he was Director at the Max Planck Institute of Microstructure Physics in Halle, Germany. Since 2017, he has been Professor of Chemistry at the Hebrew University of Jerusalem, Israel.
He is known as the inventor of time-dependent density functional theory (TDDFT). Together with Erich Runge, he proved a set of theorems which form the mathematical foundation of TDDFT. He furthermore developed the ensemble DFT of excited states, and an ab-initio approach to phonon-driven superconductivity which allows the reliable prediction of critical temperatures. He also is a co-author of two widely used textbooks, one on DFT and one on many-particle theory. In recent years, he developed the exact factorization, a novel methodology describing all aspects of non-adiabatic chemical dynamics, in particular electronic decoherence and the molecular Berry phase. His work has been recognized with several prizes and awards, including the 2016 Bernie Alder CECAM prize, the 2016 Tsungming Tu prize of the Taiwanese Ministry of Science and Technology, the Schlumberger Award with medal, and the CMOA senior medal. He holds an ERC Advanced Grant, and he is a Fellow of the American Physical Society as well as a Mercator Fellow of the Deutsche Forschungsgemeinschaft. He is a member of the International Academy of Quantum Molecular Science.

Time-dependent density functional theory: from non-equilibrium phenomena  to quantum materials engineering

Angel Rubio, Max Planck Institute for the Structure and Dynamics of Matter

One of the principal challenges in computational physics is to formulate an accurate yet computationally viable theory that can address non-equilibrium light-driven phenomena in molecules and quantum materials. Additionally, there is a need to simulate spatially and temporally resolved spectroscopies, ultrafast events, and newly emerging states of matter. In pursuit of this goal, TDDFT has emerged as the cutting-edge ab initio theoretical framework, enabling reliable and precise simulations of light-induced alterations in the physical and chemical characteristics of intricate systems. In this context, I will also introduce the recently developed framework of Quantum Electrodynamics Density-Functional Formalism (QEDFT).  This framework offers a first-principles approach to predict, characterize, and manipulate the spontaneous emergence of ordered phases in strongly interacting light-matter hybrids, referred to as polaritons These phases manifest both as ground states, resulting in novel states of matter, as well as metastable states. Noteworthy examples include photon-mediated superconductivity, cavity fractional quantum Hall physics, and optically driven topological phenomena in low dimensions. This exploration brings to light a burgeoning field, which we term "Cavity Materials Engineering" or the science of strongly correlated electron-photon interactions. We will conclude with the great challenges ahead  in this captivating field of research.

Angel Rubio received his PhD in Physics in 1991 from the University of Valladolid. He then moved to a postdoctoral position at the Physics Department at the University of California, Berkeley, from 1992 to 1994. Between 1994 and 2001, he served as an Associate Professor at the University of Valladolid. In 2001, he was appointed as a Full Professor of Condensed Matter Physics and became the director of the Nano-Bio Spectroscopy Group. In August 2014, he accepted the position of Director at the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany. Since 2017, he is  Distinguished Research Scientist at the Simons Foundation's Flatiron Institute in New York, USA.
He is renowned as one of the founders of modern "theoretical spectroscopy" and the creator of the widely used ab initio open-source project, Octopus. Recently, he developed the theoretical framework of "quantum electrodynamical density functional theory (QEDFT)," enabling the ab initio modeling of strong light-matter interaction phenomena in materials, ranging from non-equilibrium metastable states of matter to cavity-quantum materials engineering. His work has been recognized with several awards, including the 2018 Max Born Medal and Prize, the 2016 Medal of the Spanish Royal Physical Society, the 2014 Premio Rey Jaime I for basic research, the 2006 DuPont Prize in nanotechnology, and two European Research Council Advanced Grants. He is a Fellow of the APS, EPS, and AAAS, as well as a member of the Leopoldina Academy, BBAW, the European Academy of Sciences, the Academia Europaea, and the National Academy of Sciences (USA).

Interview and recollections H. Gross, A. Rubio and N. Marzari

Previous CECAM and MARVEL lectures can be found at