The school is open to graduate students and postdocs and will include four days of pedagogical lectures and one day of an advanced workshop on various topics in the field of active soft matter, including:

​Active liquid crystals / Model experiments in active matter

Fluctuation in active systems / Mechanical properties of active matter

Flow of bacterial suspensions / Hydrodynamics of tissues

Spreading is an omnipresent phenomenon which plays either negative or positive role, depending on what is spreading, an invasive pathogen or holes in a semiconductor.   There are many facets of spreading that have been studied in different fields. On the micro time-space scales compared with the lifetime of a single mover, an atom migrating over a substrate or a foraging animal, spreading splits into a set of point-like random processes, so that individual trajectories look like trajectories of random walkers. It was therefore very natural that the paradigm of random walks heavily influenced the development of the fields where spreading plays the key role – solid state electronics, turbulence, molecular biophysics, ecology, and others. At the beginning, Gaussian random walks, as a well-established concept, were extensively used. Then in many labs, it was observed that the obtained data do not fit this model, so new tools and models were demanded. The complexity of the observed phenomena can be captured in more detail with such updates as continuous-time random and Lévy walks (LW). These approaches have found a striking number of applications in diverse fields, including optics, dynamical chaos, turbulence, many-body physics (both quantum and classical ones), biophysics, behavioral science, and even robotics.

Existing models, such as LWs and fractional Fokker-Planck equations, have a strong appeal – they are very well developed, they are famous and have very good reputations and agenda. It is very tempting therefore to use them immediately when an experimentalist or a field ecologist comes with the statistical data and ask “Could you please explain it with your theories?”. But even if the matching is perfect, it does not serve an explanation. The explanation is encoded in the data and in order to extract it, the theoretician has, first of all, to understand the process which produced this data.

Spreading of cold atoms in dissipative optical potentials is an example where this path is already taken. At first, a specific classical diffusion equation was derived to capture the specific cooling mechanism (essentially quantum by its nature) governing the dynamics of atoms; and then it was possible to demonstrate that on the microscopic level trajectories of individual atoms appear as LWs. In such a way, a LW-like process has been derived from physics. Yet these experiments have also revealed that a simple LW description does not capture all features of the observed phase space dynamics. In a very different direction another microscopic origin of anomalous diffusion of bacteria was recently developed. These two examples are only part of a trend of a maturing field switching from phenomenological methods to deeper modeling, and our primary goal is to help diffuse these new ideas among the relevant practitioners.

The main emphasis of the workshop is on changing the “cargo-cult” paradigm prevailing now on the field of anomalous diffusion and random walks when it comes to their practical applications. Namely, it is not that experimental data should be analyzed in the view of the existing random walk and diffusion models but models themselves have to be constructed in a way as to capture essential physics behind the emerging spreading. That simply means that physical mechanisms running the spreading have to be understood first by those theoreticians who want to describe them with their mathematical constructions. The focus of the proposed workshop is to leave the phenomenological stage of the theory and bring together experts who work on the basics mechanism still covering a large body of models and systems.

Heavy fermion materials, transition metal oxides, and a variety of rare-earth compounds exhibit strong correlation: electrons in partially filled d and f shells of constituent atoms are delicately balanced between interaction-induced localization and kinetic delocalization, resulting in rich phase diagrams with remarkable and potentially useful switching properties. Most widespread computational approaches to materials, which are based on weak-correlation theories such as Density Functional Theory (DFT), Hartree-Fock and GW, fail to fully capture strong correlations.

The physics of strongly correlated electrons is of broad fundamental interest, with recent examples including the elusive theory of topological Kondo insulators, the formation of multipolar orders in actinide oxides and the controversial nature of high temperature superconductivity in plutonium-based materials. Some of the most societally pressing and yet long-standing issues involve the radioactive actinides, and better theoretical methods are critical to addressing nuclear waste remediation.

An emerging, cutting-edge generation of methods has begun addressing the challenge of performing realistic simulations of strongly correlated materials. Notable examples include the Dynamical Mean Field Theory (DMFT) paired with continuous time quantum Monte Carlo (CT-QMC), variational Monte Carlo and others. However, the problem remains extremely difficult, and attacking it requires a large-scale multidisciplinary effort. In this conference, we propose to bring together some major players working on various separate but synergistic sides of the problem, from both the theoretical and experimental perspectives.

From the theoretical perspective, significant progress towards a quantitative and general theory of d-electron and f-electron systems requires a combination of tools and approaches. Great strides have been made in DMFT. However, advances towards a realistic description rely on a stronger connection to underlying weakly correlated theories. They further rely on improved Monte Carlo methods able to address dynamical phase problems in the associated auxiliary problems. Promising new variational approaches should also be explored and hopefully integrated into the same toolset, and all these ideas should be combined with modern methods for constructing coarse-grained models. Finally, close collaboration with experimentalists is paramount to focusing this effort.

We propose to bring together several prominent researchers in correlated electrons, f-electron materials, and the foundations and extensions of weakly correlated methods. All invitees develop unique and relevant computational or experimental methods. The emphasis is on members of several centers in the Czech Republic and Israel, between which we hope to form a long-term collaboration; however, a select group of leaders in the field from elsewhere will also attend.

The main emphasis is on theory and method development, and discussions are planned between experts from a diverse set of disciplines and scientific communities that have made relevant contributions to the field but would not normally meet each other. However, we also propose to put these theorists in close contact with experimentalists that have unique access to some of the most groundbreaking studies in Europe on strongly-correlated 5f systems, and provide tutorials on x-ray magnetic circular dichroism (XMCD), x-ray absorption near-edge structure (XANES), electron energy-loss spectroscopy (EELS), electron-probe microanalysis (EPMA), and transmission electron microscopy (TEM).

The great 20th century physicist, Richard P. Feynman, stated in his famous 1981 lecture titled “Simulating Physics with Computers” that “Nature isn’t classical … and if you want to make a simulation of Nature, you’d better make it quantum mechanical, and by golly it’s a wonderful problem, because it doesn’t look so easy.”1,2 In recent years, this brave prophecy started to become reality and quantum computing holds great promise to revolutionize the computational capabilities of human kind. In contrast to the architecture of contemporary (super)computers that relies on classical mechanics and binary bits, quantum computers harness the laws of quantum mechanics and its unique concepts (such as coherence, superposition, and entanglement) to form bits of an infinite manifold of possible states (often called qubits) and couple them to each other.

This new computational platform calls for completely new algorithmic paradigms. To exemplify this, consider quantum chemistry calculations that are considered to be the first killer application for quantum computers.3-10 On traditional computers one usually approximates the many-body wave function as a linear combination of basis-functions (usually Slater determinants constructed from localized, plane-wave, or real-space grid-based orbitals) using, e.g. the configuration interaction or coupled clusters expansions.12 Alternatively, a the single-determinantal wave function of a reference non-interacting system can be used for this approximation within the realm of density functional theory.13-15 In contrast, given a quantum computer one can obtain exact mapping between the quantum mechanical problem to be solved and the actual state of the quantum circuitry. Hence, the system can be prepared in an initial quantum state and be driven towards the desired solution that can eventually be read directly from the system’s state at a certain accuracy.

However, with the recent great advances in the construction of actual quantum computational platforms16-17 and the emergence of their first practical quantum chemistry applications3-10 come also great challenges of shifting the computational paradigm within the relevant user communities. The main hurdles can be identified as: (i) reluctance to study a completely new computational language and jargon that are out of the comfort zone of traditional users; (ii) the need to invest efforts and resources in understanding the interplay between the physical world to be modeled and the new computational platform; and (iii) the natural distrust in an immature and exploratory technology.

Nevertheless, the expected gain for those who make the step forward is very high. This is well supported by the success of the computational methodologies developed by the 2013 Nobel prize Laureates Michael Levitt, Arieh Warshel, and Martin Karplus, and their great mentor, the late Shneior Lifson, who constructed highly efficient algorithms that were able to utilize the very poor computational resources available at the time to perform multiscale computer modeling of proteins. In a sense, the current status of quantum computing is similar to the state of classical computers when these pioneering achievement, of untouched scientific grounds, have been made.

In light of all of the above, the objective of the tutorial is to help potential quantum computer users in general, and those coming from the quantum chemistry community in particular, overcome the abovementioned potential energy barriers for using this new and fascinating computational platform. The participants will be exposed to the basic theoretical concepts of quantum computing, to the technical and operational aspects of the available platforms, and to the fundamentals of translating and mapping an actual physical problem onto a quantum computing circuit. To this end, experts from three different disciplines, namely, computer science, quantum chemistry, and the computer technology industry, will be gathered to provide tutorial level introductory lectures assuming no preliminary knowledge on the subject.

The suggested tutorial will complement recent CECAM workshops, such as “Synergy Between Quantum Computing and High-Performance Computing” that aimed at identifying major challenges and future directions. It will do so by making the field accessible to non-experts, who have no prior experience and knowledge on the theory and practice of quantum computing. Therefore, the knowhow gained in this workshop is expected to expand the community of quantum computing users from the chemistry and physics disciplines. Furthermore, we aim to seed collaborative efforts between quantum chemists, physicists, and computer scientists to form synergistic workgroups that will develop new ways