Ultrafast Physics from molecules to nanostructures

The impressive progress in ultrafast laser technology, ranging from the femtosecond to the attosecond timescale and from the THz to the XUV frequency range, is making possible to probe real-time electronic and nuclear dynamics in atoms, molecules and solids[1]. Fundamental insight can be gained into the primary photoinduced processes in systems with growing level of complexity[2]. The capability of following and steering ultrafast dynamics has tremendous impact in a wide range of applications, from materials science[3] to life sciences.

Clearly, advances in theories and methods for modeling ultrafast processes inevitably require an intense exchange with the experimental community due to the complexity of the systems and of the measurements. In the last decade the effort in developing predictive and computationally feasible methods has virtually exploded. Ab initio approaches based on DFT and nonequilibrium Green’s function (NEGF)[4] have recently made contact with timeresolved experiments in 2D systems and nanostructures. Other ab initio methods based on wavefunctions (e.g., ADCn, CASPTn) or reduced quantities (e.g., TDDFT, NEGF) for modeling ultrafast processes enable to access the electron-nuclear subfemtosecond dynamics in molecules. Furthermore, accurate real-time numerical methods have been put forward for strongly correlated model systems (e.g., TD- DMFT and DMRG). This workshop will gather world-leading experts in theory and experiments, enabling a cross-fertilization which will enable to advance the state of the art in ab-initio methods. In fact, the rapid development of experimental techniques has not been followed by a simultaneous integration with the ab-initio computational community. The result is a scarce availability of numerical tools for crucial systems of technological or fundamental interest, e.g., biomolecules, large nanostructures and materials with technological application. One of the key challenges is therefore to extend the range of application of material science and chemistry codes to the study of out-of-equilibrium properties. To this purpose, it is crucial to let experimental, theoretical and computational scientists meet and debate on crucial questions like: how to extend the accuracy of ab-Initio methods out-of-equilibrium? How to efficiently benefit from the advances in computation facilities to simulate the nonequilibrium dynamics of complex materials? How to translate laser-pulse features into boundary conditions and suitable approximations for the computational tools? Can we devise a series of tools and procedures to provide to the community?