The study of time-domain quantum processes with ultrafast pulses is made timely by the x-ray free-electron laser (FEL) machines now coming into operation and from the development of laser technology. The first type of radiation sources will generate intense, coherent, short X-ray bursts of femtosecond duration. The Linac Coherent Light Source at the SLAC national laboratory became online in the fall of 2009. In Europe a similar facility is under construction in Hamburg (XFEL).

The second type of radiation is based on tabletop laser systems, which can produce femtosecond pulses throughout the visible and infrared regions of the spectrum.  These can further be converted into low-energy X-rays by an extremely non-linear process called high-order harmonic generation  (HHG). Novel properties of short-wavelength radiation produced via HHG are the ultrashort pulse duration and the high degree of transverse and longitudinal coherence.  The pulses produced in this way will have durations down to the attosecond scale (1 asec = 10^-18 s), which is the natural time-scale for motion of electrons around their nuclei. Indeed, the most rapid events in molecules, atoms and solids occur on the atto- or femtoseond timescale and nanometre scale, i.e., the wavelength scale of X-rays.

New light sources will make it possible to study quantum processes directly in the time-domain, for example, by pump-probe experiments. In this network, we will aim at developing theory for time-dependent descriptions of quantum processes. This network joins 4 Nordic groups and strives to strengthen the research not only in the Nordic countries but also internationally.

The combination of the 4 groups combines experience with and knowledge of a relatively large number of physics systems ranging from individual atoms over biomolecules to quantum and quantum ring structures. All these different systems are studied by different methods, which largely can be divided into ab initio, or first principles approaches and theoretical modeling. In both cases the methods and theories used by the 4 core nodes have strong relations and are highly relevant across the sub-groups.

Quite an experience is developed within each sub-group, and the network will constitute a perfect channel for transfer of knowledge between the nodes.  In particular when it comes to research training. As it is now, the group leaders of the individual groups supervise the students of each node separately. The students would be exposed to many more physical systems and methods through the network.