Speaker
Description
Positronium (Ps), the bound state of an electron and its antiparticle positron, serves as a good probe for fundamental physics. As the lightest purely leptonic atom containing an antiparticle, Ps offers unique opportunities for precision tests of bound-state quantum electrodynamics (QED) and investigations into matter-antimatter asymmetry—the mystery underlying our matter-dominated Universe.
One of the long-standing goals in Ps research is the realization of Bose-Einstein Condensation (BEC) of Ps (Ps-BEC). Given its low mass, Ps stands out as an excellent candidate for achieving the first BEC containing antiparticles. Ps-BEC would allow us to study gravitational effects on antiparticles (specifically positrons) through interferometer experiments [1]. Additionally, it holds interesting potential for creating a 511-keV gamma-ray laser [2].
The challenge in achieving Ps-BEC is to satisfy stringent conditions: a high number density (on the order of $10^{18}$ cm$^{-3}$) and ultra-cold temperatures (below 10 K) within the short Ps annihilation lifetime of 142 ns. In this presentation, I will introduce the physics of Ps-BEC and provide an overview of our recent progress and future developments in creating dense and cold Ps using a recently proposed method [3].
This work was partially supported by JST FOREST Program (Grant Number JPMJFR202L), JSPS KAKENHI Grant Numbers JP16H04526, JP17H02820, JP17H06205, JP17J03691, JP18H03855, JP19H01923, MATSUO FOUNDATION, Mitutoyo Association for Science and Technology (MAST), Research Foundation for Opto-Science and Technology, The Mitsubishi Foundation, TIA Kakehashi TK17-046, TK19-016.
[1] D. B. Cassidy and A. P. Mills, Jr., phys. stat. sol. (c) 4, 3419 (2007).
[2] H. K. Avetissian et al., Phys. Rev. Lett. 113, 023904 (2014); Phys. Rev. A 92, 023820 (2015).
[3] K. Shu et al., J. Phys. B: At. Mol. Opt. Phys. 49, 104001 (2016); A. Ishida et al., JJAP Conf. Proc. 7, 011001 (2018).
