Impurity channels of the long-lived Mossbauer effect

Recent reports have suggested that the nuclear resonant absorption of a long-lived Mossbauer state e.g., (93m)Nb is mediated by an entangled photon pair (biphoton) rather than by a single photon. Multipolar nuclear excitation in crystals of a single isotope with a natural abundance of 100% spreads in a region containing billions of identical nuclei. As a consequence of the delocalisation, additional decay channels via the impurities, the crystal defects, and the sample boundary, give rise to a density- and temperature-dependent decay. In this letter we report our discovery of impurity channels, the intensity of which is proportional to the square of the (93m)Nb density.