Article: published in Physical Review Letters by Manuel I. Marques and R. Delgado-Buscalioni, IFIMAC researchers and members of the Material Physics Department and Theoretical Condensed Matter Physics Department.
In general, the interaction forces between identical resonant molecules or nanoparticles, optically induced by a quasimonochromatic isotropic random light field exhibit a far-field oscillatory behavior at separation distances larger than the light wavelength. In this work, we show that the oscillations disappear when the frequency of the random field is tuned to an absorption Fröhlich resonance, at which the real part of the particle’s electric polarizability is zero. At the resonant condition, the interaction forces follow a long-range gravity like inverse square distance law, which holds for both near- and far-field separation distances. [Full article]