Speaker
Description
We study laser cooling and trapping of hot para-positronium bunches as produced by a Surko trap. While laser cooling via radiation pressure is a very well established technique to slow and cool down neutral atoms below mK, the fast ground state annihilation and high recoil shift poses challenging extra limitations on the required laser powers and frequencies. Some earlier work suggests viable prospects for obtaining a cold sufficiently dense ensemble nevertheless. Our theoretical study sets out to explore new ways for these exotic atoms beyond simple Doppler-cooling on the $1^3\mathrm{S}$-$2^3\mathrm{P}$ transition by including an extended upper state manifold and extra transverse lasers on the $2^3\mathrm{P}$-$3^3\mathrm{D}$ transition. The specific objective of this study was to examine the effect of this additional excitation on the quality of positronium atoms’ cooling process. This research employs semi-classical approaches of simulating light-matter interactions. We successfully found experimentally reasonable values for the lasers’ parameters, whose proper application can lead to an effective slowing of positronium. With the presented scheme we were able to achieve an acceptable and fast slowing effect while the majority of atoms were not annihilated.
Future extension to collective cooling and trapping in cavities or hollow core fibres could be the basis of new discoveries in the investigation of cold Ps systems even pointing towards superradiant lasing and Bose-Einstein-condensates.