Numerical Integrators for Fast and Scalable Quantum Molecular Dynamics

Speaker: Andre Schleife (UIUC)
Date: Friday, 4 December 2015, 08:30-10:00
Session: Numerics II
Talk type: Short talk (15 min)

Abstract: We are in the process of establishing a collaboration in order to research and develop numerical techniques that will enable accelerated computational quantum-molecular dynamics simulations. When developing such techniques, it is necessary to take the massively parallel hybrid architectures of modern super-computers into account. More specifically, together with applied mathematicians we will explore and implement explicit numerical integrators for the time-dependent Kohn-Sham equations that reduce numerical error and allow for increased integration time steps. The numerical integration of the time-dependent Kohn-Sham equations is highly non-trivial: Using a plane-wave basis set leads to large Hamiltonians which constrains what integrators can be used without losing computational efficiency. The outcomes of this project will be available to the broad computational electronic-structure community via an implementation into the Qbox/Qb@ll code, that scales well on modern high-performance computers. Applications of this work will be complicated non-equilibrium systems in which ultrafast excited-electron dynamics is closely connected to the trajectory of ions. Hence, it is necessary to go beyond the prevalent adiabatic Born-Oppenheimer approximation, because within this approximation ultrafast electron dynamics is inaccessible. We envision that this work opens up the possibility to study applications such as ultrafast pump-probe experiments and interaction of high-intensity laser fields with solid-state matter involving hundreds of atoms and thousands of electrons.