The following is overly simplistic, but also surprisingly intuitive for a particular hypothesis, so it is worth the effort to try to get down an explanation for the Rossi/Parkhomov effect . one containing less than a thousand words, by using a few images.
Here is an image of the Li-7 nucleus. Keep in mind the single tenet that like-charges repel. In a small nucleus, and ignoring QM for a moment in favor of macro geometrical restraints this means that nesting of nucleons becomes complicated. since in the case of 3 protons, they must be kept apart by neutrons. http://www.lnhatom.com/Lithium%207.jpg To oversimplify the point which will be made below: the red balls are the 3 protons, and they do not touch each other because the 4 neutrons form a tetrahedron which effectively separates them, and a tetrahedron is an especially stable geometry. Therefore, this isotope should be more stable than one where like charges have the possibility of fleeting contact. In fact, almost 93% of natural lithium is this particular isotope: Li7 despite this isotope being a drip line anomaly in itself. That stable tetrahedral nesting arrangement at the core of Li7 is not the case with lithium-6 however; and this nucleus becomes unstable, particularly when stressed by incursion of positive charge (such as by the approach of a proton). That is because the only stable geometry which we can visualize for Li6 is to have a near-planar hexagonal arrangement of alternating neutrons and protons, arranged somewhat like a benzene ring, which is not spherical and not stable wrt the strong force: https://dlnmh9ip6v2uc.cloudfront.net/assets/0/4/e/8/2/519fa09dce395f8b080000 00.png Therefore, a planar structure like the one above, when it is located inside orbiting electrons is itself unstable, and the natural charge-equalizing tendency is for the hexagonal plane to revert to something more compact, like a sphere. Therefore on occasion, and as several papers are now suggesting, the lithium-6 nucleus temporarily takes the form of 3 deuterons, arranged in the X,Y & Z axes where the neutrons of each deuteron are in contact. This is where Efimov state comes into play. Now the visual image of greatest impact is to imagine the 3 deuterons expressing the Efimov "Halo Effect," which is state of oscillating balance and "Russian nesting dolls" geometry as predicted by Efimov. This state should function like a pump, among other possibilities. But a pump for what? For those who suspect that the Dirac sea, as expressed in Don Hotson's many papers, is accessible as a point source, then one suggestion is that the Li6 nucleus can act like a pump for "something" which is intrinsic to the Dirac sea. and since epos are ruled out by the lack of observed radiation, then that something is most likely "spin", or a subset like angular momentum, or a quantum of spin: a Dirac spinor, or something along those lines. Thus the Li6 nucleus would be the a gateway for spin energy coupling - especially at a temperature where the 3-deuteron geometry is favored. This temperature seems to be in the range of 1400K in the dogbone. This hypothesis suggests that the key to the excess heat in dogbone-type devices is lithium-6. The thermal anomaly will be maximized by enrichment in the isotope, and should go away with all Li7. Thus, this hypothesis, despite being complicated in detail - is easily falsifiable, unlike most of the other explanations floating around, which generally fail due to the lack of observable high energy radiation.
