Quantum Theory / Particle Physics
December 8, 2016
Scattering of light by matter has been studied extensively in the past. Yet, the most fundamental process, the scattering of a single photon by a single atom, is largely unexplored. One prominent prediction of quantum optics is the deterministic absorption of a travelling photon by a single atom, provided the photon waveform matches spatially and temporally the time-reversed version of a spontaneously emitted photon.
Here we experimentally address this prediction and investigate the influence of the photon’s temporal profile on the scattering dynamics using a single trapped atom and heralded single photons. We don't often think of photons as being spread out in time and space and thus having a shape, but the ones in this experiment were some four meters long. Christian Kurtsiefer, Principal Investigator at CQT, and his team have learned to shape these photons with extreme precision.
According to the quantum mechanics that photon is an unstructured particle. How the concept of unstructured photon is able to describe the different shapes and four meter long of photon?
In addition to four meters long and shapes of photons, how two opposites’ charged particles such as electron and positron absorb and emit neutral and unstructured photons?