Challenges and advances of positronium Bose-Einstein condensation

While scientists in the USA have accomplished Bose-Einstein Condensation (BEC) of inert gas and alkaline atoms successfully, a challenging question comes into the other’s mind why not BEC of Positronium (Ps), even though, its lowest lifetime (142 ns)? A few auspicious methods of having BEC were invented and successfully applied in the atoms of infinite lifetime. But in case of Ps-BEC laser cooling is considered to be the best method provided we can meet the requisite parameters. Using the medium range e+ beam intensity we explored some solid surfaces for the laser cooling of Ps but Ps-BEC could not be achieved. Because the intensity of pulsed beam was not enough to have the phase space density, outgoing Ps from the surface with thermal motion could not be controlled inside the scattering chamber and laser-Ps interaction was without synchronization. Hence, scientists of different laboratories have been searching materials of high density Ps production, intense pulsed e+ beam, advanced detector and image reconstruction techniques. Recently we have developed calumnious silicon nano-wires of various diameters and found the signature of a long-life component of Ps and estimated the Ps production density about 1015 Ps/cm3. It is an ideal case for the achievement of the Ps-BEC. The details of these systems are explained in the following sections.