Time reversal symmetry in quantum optics

21.06.2013, 00:00

Newsletter 6

Time reversal symmetry is a powerful concept in physics. It applies to low-energy quantum physics as long as the evolution of the quantum system can be described as unitary. In this sense the spontaneous emission process of a photon by an atom or an atom-like system is a reversible process so long as the photon is not detected. In recent years it has become more and more popular to use time reversal symmetry when planning the implementation of an optics or quantum optics experiment. We review the basic idea underlying time reversal methods, illustrate it with several examples and discuss several implications. The discussion includes an on-going experiment at MPL regarding the demonstration of time-reversed spontaneous emission, i.e., the efficient absorption of a single photon by a single atom.

Contact: markus.sondermann(at)mpl.mpg(dot)de
Group: Leuchs Division
Reference: G. Leuchs et al., Physica Scripta 85, 0581001 (2012); selected by the editors of Physica Scripta as a ‘Highlight of 2012’