Photon drag of a Bose-Einstein condensate

Abstract

Kepler’s observation of comet tails initiated the research on the radiation pressure of celestial objects and 250 years later they found new incarnation after the Maxwell’s equations were formulated to describe a plethora of light-matter coupling phenomena. Further, quantum mechanics gave birth to the photon drag effect. Here, we develop a microscopic theory of this effect which can occur in a general system containing Bose-Einstein– condensed particles, which possess an internal structure of quantum states. By analyzing the response of the system to an external electromagnetic field we find that such a drag results in a flux of particles constituting both the condensate and the excited states. We show that in the presence of the condensed phase, the response of the system acquires steplike behavior as a function of the electromagnetic field frequency with the elementary step determined by the internal energy structure of the particles. ©2018 American Physical Society