Possibility of forming a stable Bose-Einstein condensate of $2{}^3{S}_1$ positronium atoms

Abstract

The confined variational method in conjunction with the orthogonalizing pseudo-potential method and the stabilization method is used to study the low energy elastic scattering between two spin-polarized metastable positronium Ps(2\,${}^3{S}_1$) atoms. Explicitly correlated Gaussian basis functions are adopted to properly describe the complicated Coulomb interaction among the four charged particles. The calculated $s$-wave scattering length ($\approx 8.5a_0$) is positive, indicating the possibility of forming a stable Bose-Einstein condensate of fully spin-polarized $\text{Ps}(2{}^3{S}_1)$ atoms. Our results will open a new way of experimental realization of Ps condensate and development of ${\hat{I}}^3$-ray and $\text{Ps}(2{}^3{S}_1)$ atom lasers.

6 pages, 1 figure