Fázisprobléma

Fázisprobléma, or phase problem, refers to a fundamental challenge in several scientific fields, particularly in crystallography and optics. In crystallography, it arises from the fact that while diffraction experiments can determine the amplitudes of the scattered X-rays, their phases are lost. These phases are crucial for reconstructing the electron density map of a crystal, which in turn reveals the atomic structure. Without the phase information, it is impossible to uniquely determine the arrangement of atoms within the crystal. Various methods, such as direct methods, isomorphous replacement, and anomalous dispersion, have been developed to overcome this limitation.

In optics, the phase problem relates to the reconstruction of an object from its intensity measurements. Intensity is the square of the amplitude of the light wave, meaning that phase information is lost during measurement. This makes it difficult to fully reconstruct the original object, especially in applications like digital holography or microscopy. Similar to crystallography, techniques are employed to either retrieve or bypass the need for phase information to achieve accurate image reconstruction. The core of the fázisprobléma lies in the irreversible loss of phase information during measurement, necessitating sophisticated algorithms and experimental strategies for its resolution.