An interesting new theory paper has been submitted to Cornell's ArxivÂ
http://arxiv.org/ftp/arxiv/papers/1406/1406.3941.pdf
Despite its not being entirely new (see Ahern, Johnson ...) it's well worth reading.
In particular, it explains how "discrete breathers" can be created either above a specific temperature, or by an external stimulus. Also that they result in a quasi-particle with a high-temperature "hot spot" which propagates at half the speed of sound. It seems in other studies that these can collide with lattice discontinuities, so the actual NAE may be there. It doesn't explain how resultant gammas can be made to disappear, but Hagelstein/McKubre's work on photon/phonon coupling may provide the answer to that.
