Inspired by recent advances in the generation of ultrashort, high-intensity laser pulses, the proposed research will investigate and develop theoretical and computational tools to plan, understand, and predict experiments probing the quantum dynamics of molecular systems at the attosecond timescale. Targeting high-accuracy simulation methods, nuclear and electronic degrees of freedom will be treated on an equal footing without invoking the Born-Oppenheimer approximation.

The main tool, which allows breaking the exponential computational cost of many-particle systems, is the time-dependent bivariational principle. The proposed reasearch is highly interdisciplinary with components ranging from mathematical analysis to software development, and involves core members from three continents with expertise in mathematics, physics, and chemistry.