Some other science news of interest... Slow neutrons are dense http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.107.134801
And this one involving Rydberg states... Excited atoms spin out of equilibrium http://physics.aps.org/pdf/10.1103/PhysRevA.84.031402.pdf "What makes the setting different from traditional experiments with cold atoms, and therefore particularly interesting, is the use of atoms in highly excited states—so-called Rydberg states [4]. An alkali-metal atom, with its single active electron, shares many properties with the hydrogen atom. Excited states form a Rydberg series whose states can be labeled, just like in hydrogen, by the principal quantum number n. Interesting physics emerges in the presence of more than one Rydberg atom, as the large distance between the nucleus and the valence electron renders these atoms into electric dipoles. Depending on the particular Rydberg state, the interaction between two such atoms is then either determined by a van der Waals or a dipole-dipole potential. The authors consider the former potential, which is, in principle, also present between ground-state atoms. The striking difference, however, is that the interaction between atoms in Rydberg states is enhanced by a factor of up to n^11. For values of the principal quantum number typically used in experiments, n=40…80, this means an increase of 10 orders of magnitude, i.e., the interaction affects even atoms that are separated by several micrometers. This is in contrast to the contact potential usually present between ground-state atoms. In the most extreme case, interaction-induced level shifts are so huge that a simultaneous excitation of two nearby atoms to Rydberg states is virtually impossible [for an illustration see Fig. 1(a)]. This so-called Rydberg blockade mechanism [5] lies behind a number of exciting phenomena that make Rydberg atoms useful for applications ranging from quantum information processing and quantum simulation to nonlinear quantum optics and ultracold chemistry."
