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Photonic counterparts of Cooper pairs
Marcelo Franca Santos (Universidade Federal do Rio de Janeiro)
Photons are the elementary particles of light. Contrary to most particles, photons do not interact directly with each other in vacuum.
However, when propagating in a material, e.g. water, photon pairs may interact through the medium. In the Raman effect, for example, it is possible that a photon creates or absorbs a vibrational excitation of the material. In this work, we demonstrate theoretically and experimentally that photon pairs may interact via a virtual vibration, meaning that the energy exchanged in the process does not correspond to a quantum of vibrational energy. The same process occurs in a metal at very low temperatures, where virtual vibrations of the medium create an effective attractive interaction between electrons, forming the so-called Cooper pairs. This phenomenon changes a normal metal into a superconductor. We have shown the analogue of this phenomenon with light, namely an effective photon-photon interaction mediated by a virtual vibration, i.e, a photonic-like Cooper pair. An important next step is to test how far the analogy with superconductivity extends.
Contact : Marcelo Franca Santos
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