On certain electromagnetic field-induced interatomic interactions

The long-range retarded dispersion interaction potential between two neutral isotropic polarizable systems is attractive with the characteristic Casimir-Polder form $\sim - 23 \alpha_1 \alpha_2/R^7$, where $\alpha_i$ is the static electric dipole polarizability of a particle and $R$ is the intersystem separation. In contrast, the long-range retarded interaction between an electron and an ion is repulsive with form $11 \alpha/R^5$, where $\alpha$ is the ion's polarizability. Theoretically, a way to form a stable BEC with attractive $1/R$ interactions was proposed~[1]. Using external laser beams the average interatomic potential is $\sim -11 (I q^2 / c) \alpha(q)^2/R$, where $I$ is the laser intensity, $\alpha(q)$ the atomic polarizability, and $cq$ is the frequency. The connections between this (under certain conditions) ``artificial gravity-like interaction'' and more standard long-range dispersion forces are explored. In addition, similarities to ``optical binding'' are discussed. Supported in part by the NSF.\\[4pt] [1] D. O'Dell, S. Giovanazzi, G. Kurizki, and V. M. Akulin, Phys. Rev. Lett. \textbf{84}, 5687 (2000).