Phenomenological ( hence, not specific to LQG ) constraints on anomalous dispersion relations can be obtained by considering a variety of astrophysical experimental data, of which high-energy cosmic rays are but one part.
22.
In this technique, atoms'inner electrons absorb X-rays of particular wavelengths, and reemit the X-rays after a delay, inducing a phase shift in all of the reflections, known as the " anomalous dispersion effect ".
23.
The phase velocity of electromagnetic radiation may under certain circumstances ( for example anomalous dispersion ) exceed the speed of light in a vacuum, but this does not indicate any superluminal information or energy transfer.
24.
He published his first paper, which summarised his thesis " On anomalous dispersion in mercury and in lithium ", jointly with Edoardo Amaldi in 1928, and another paper with him the following year on the Raman effect.
25.
The mathematics upon which MAD ( and progenitor Single wavelength anomalous dispersion ) were based were developed by Jerome Karle, work for which he was awarded the 1985 Nobel Prize in Chemistry ( along with Herbert Hauptman ).
26.
However, X-rays can be generated at special frequencies just below the frequencies corresponding to core electronic transitions in a material, as the index of refraction is often greater than 1 just below a resonant frequency ( see Kramers-Kronig relation and anomalous dispersion ).
27.
With the help of the director of the Institute of Physics, Orso Mario Corbino, Segr?was able to transfer to physics, and, studying under Fermi, earned his laurea degree in July 1928, with a thesis on " Anomalous Dispersion and Magnetic Rotation ".
28.
In a region of anomalous dispersion, where low-frequency components have faster group velocities than high-frequency ones, the opposite of the above situation occurs : the onset of the precursor is characterized by a long period, and the period of the signal decreases with time.
29.
In some unusual circumstances, called cases of anomalous dispersion, the rate of change of the index of refraction with respect to the wavelength changes sign ( becoming negative ), in which case it is possible for the group velocity to exceed the speed of light ( " v " g > " c " ).
