Hot Topics in Science: Bouncing Light Off Light
Dr. Andrew Hamilton, Physical Sciences Tutor (Physics)
Can a ray of light bounce off another ray of light? When we shine a laser beam at another laser beam, they do not appear to bounce off one another like a beam of marbles would. The beams pass through each other seemingly undisturbed by the other’s existence. This phenomena comes naturally from the classical theory of electromagnetic waves. However, within the quantum description of light there is a possibility for a particle of light, the photon, to bounce off another photon. Evidence for this extraordinarily rare process has recently been found using the ATLAS detector at CERN in Geneva, in a paper submitted to Nature Physics. This talk will present the physics behind light-by-light scattering and detail the experimental evidence found by the ATLAS Collaboration.