Despite the extensive use of polycapillary x-ray optics for focusing and collimating applications, there remains a significant need for characterization of the coherence properties of the output wavefield. In this work, we present the first quantitative computational method for calculation of the spatial coherence effects of polycapillary x-ray optical devices. This method employs the coherent ...

Using general two-and one-way representations for scattered wavefields, we fully describe two-and one-way extended images obtained in wave-equation imaging. This formulation explicitly connects the wavefield correlations done in seismic imaging with the theory and practice of wavefield interferometry. We show that extended images actually behave as local scattered fields in the image domain. Th...

We calculate the supersymmetric type II string partition function in a flat background for the situation where the world-sheet is hyperelliptic. We show explicitly that the contribution to the cosmological constant from hyperelliptic world-surfaces vanishes for genus< 20. This implies, in particular, that the cosmological constant vanishes completely to two loops. Due to the decoupling of the h...

We study the Gouy phase of a scalar wavefield that is focused by a lens suffering from primary spherical aberration. It is found that the Gouy phase has different behaviors at the two sides of the intensity maximum. This results in a systematic increase of the successive wavefront spacings around the diffraction focus. Since all lenses have some amount of spherical aberration, this observation ...

S U M M A R Y Modern acquisition of seismic data on receiver networks worldwide produces an increasing amount of continuous wavefield recordings. In addition to manual data inspection, seismogram interpretation requires therefore new processing utilities for event detection, signal classification and data visualization. The use of machine learning techniques automatises decision processes and r...