The aim of this school is to equip students with the essential knowledge, practical skills and computational tools needed to tackle today’s novel and challenging problems in materials science and non-equilibrium physics. We will introduce students to many-body perturbation theory (MBPT) approaches, including advanced concepts, for modelling non-equilibrium phenomena from first principles. We will also discuss how model systems can help overcome some of the limitations of fully ab initio schemes.

The school features theoretical and technical lectures in the morning, followed by hands-on in the afternoon. Distinguished scientists and emerging young researchers in the field of condensed matter and non-equilibrium physics will provide the theoretical background and technical lectures. Each topic will be introduced with a general overview of experimental measurements and/or physical problems, with emphasis on the connection to the simulations performed by the students in the hands-on sessions, which will be led by the main developers of the codes YAMBO[1] and CHEERS[2].

The main topics covered include the GW approximation for quasiparticle corrections and the Bethe-Salpeter Equation (BSE) for excitons, with a focus on  recent developments in the YAMBO code. Furthermore, we will introduce the specific usage of the code in massively parallel environments equipped with modern accelerated video cards (GPUs).Then, students will be introduced to nonequilibrium Green’s function theory (NEGF), with theoretical  lectures covering modern pump-and-probe experiments based on ultra-short laser pulses as well as nonlinear optical properties. Recent developments in the YAMBO code to capture the physics of nonequilibrium quasiparticles, excitonic energies and the simulation of time-resolved ARPES spectroscopy will be discussed. Finally, students will be guided through the main concepts needed to treat  dynamical self-energies within NEGF in order to address dissipative mechanisms and carrier (exciton) dynamics, with hands-on on the usage of the linear scaling implementation available in the CHEERS code.

YAMBO is a flagship code of the MaX Centre of Excellence and of the recently established ICSC PNRR Italian National Centre for HPC, Big Data and Quantum Computing.

CHEERS is a simulation tool for correlated hole-electron evolution from real-time simulations developed at the University of Rome Tor Vergata.