Bob Higgins wrote:
The problem with the phonon is that its wavelength is extremely short. The attenuation coefficient for waves, in general, is typically quoted in dB/wavelength; and nature abhors a too small value for such a number.
Come to think of it, isn't it arguable that wavelength enhancement, of an extreme variety, is part of the gain mechanism leading to runaway? IOW there is a emergent property of the vibrational makeup of the Ni-H system at coherence, which results in the runaway anomaly.
It is reasonable to suggest that in addition to the collective lattice phonon waves, which would go coherent during the runaway reaction, we have nuclear spin at a resonant wavelength, possibly related to proton NMR, which aligns. A cluster of dense hydrogen could also be the carrier of PPP (phonon-plasmon-polariton) coherence not the nickel - and the corresponding phonon wavelength is longer from the start. We have talked about "triple coherence" before. Triple coherence aka “superradiance” involves three aligned wave categories such as photon, phonon and magnon (spin wave) coherence. Triple coherence promotes tunneling. However, in the runaway reactions we are discussing - there is no magnon contribution (apparently).
Is there some other wave structure which can substitute to allow triple coherency? A wildcard for another relevant contribution, which could show up in nickel powder is the SAW phenomenon - surface acoustic waves, which can be present on particles of larger size than nanoparticles, and it can be noted that the Thermacore runaway involves fairly large powder particles - 200 mesh. Possibly these larger particles promoted the SAW.
SAW are different from phonon vibration but easily resonant with them. The APS abstract proposes coupling "single phonons" at gigahertz frequencies, very high for sound, presumably with with wavelength based on speed of sound in a semiconductor, to EM photons in the near infrared. That does not seem to be a wavelength spread which can go resonant at first glance, so maybe this paper is not relevant. If it is relevant, the "single phonon" would NOT be a large lattice, but a small particulate such as a bound cluster atoms of UDH - dense hydrogen with properties defined as a PPP.
There is no suggestion of gain in the paper, only a surprising coupling - and any gain would need to come from another mechanism which would be intrinsic to dense hydrogen, such as Mills' suggestion of reduction in orbital angular momentum or a completely new kind of nuclear reaction (which calls for two miracles in place of one). Another possibility for gain is DCE or a dynamical Casimir effect, which is known. Another is mass-to-energy conversion of slight excess average mass in protons (assuming proton mass is not quantized) but that is also in the two-miracle category. If Alan Goldwater is seeing 511 keV radiation, then we can invoke the epo field of Dirac/Hotson. That one is probably in three-miracle territory.
However, if IR light does indeed has a wavelength which couples to GHz phonons, then there could be an inherent mechanism for gain in the coupling itself, since the massless photons of light carries so little energy compared to the mass x velocity product being resonated. This is especially true if superradiance is the emergent property of this coherence. This area lies in the unknown borderland between EM waves at lightspeed cohering with acoustic waves in a special way - and that they couple well at all is interesting since the frequencies are so different. Perhaps they couple via SAW.
Of course, this is an overly simplified approach to such a complicated mechanism, and the paper does not suggest violation of Laws of Thermodynamics. It does seem to suggest a coupling of EM to acoustic waves which can lead to triple coherency.
