Would that mean that the gravitational bending of light is actually due to refraction by the superfluid, because the index of refraction is proportional to the density of a superfluid? But that would mean that emergent gravity’s bending of light would be frequency dependent, wouldn’t this be observable? Wouldn’t a moving observer feel a larger superfluid density in front of them and thus a larger emergent gravitational pull forward leading to runaway acceleration in the direction of motion? Is mass then due to vortice quantization? What is the wave propagation speed of this superfluid, wouldn’t this finite speed be the effective speed for the propagation of effective gravitational interactions?

I also gather that these wave packets have stretched out over time. But if their expansion rate is not that of the expanding background space, wouldn’t this imply that their overlap, again on average and roughly speaking, changes in phase over time as a kind of beat.

Perhaps that accounts for the observed acceleration in the Universe’s expansion rate, this being simply one upward trend of a longer-term (and lengthening) cycle.

Presumably this cycle, if it exists, was much shorter during the Big Bang and the resulting slight relative changes in the strength of gravity and dark energy played a role in condensing out particles and reheating and so on. Also, if at an early stage the waves didn’t overlap at all then gravity (in this model) would be absent and dark energy unckecked. Inflation anyone?

Just in case people missed it, the MiniBoone Collaboration released its latest paper on the observed neutrino excess

http://arXiv.org/pdf/0812.2243v2

One of the great mysteries of modern physics is why gravity is so much weaker than the other forces (strong, electromagnetic, and weak). Many great minds have worked to incorporate gravity into the same sort of relativistic quantum field theory that we use to describe the other three, and have failed more or less utterly for decades. Is there something fundamentally different about gravity? Einstein’s general relativity, which links gravity to the warping of spacetime in the presence of matter and energy, is extremely successful in accounting for a wide variety of phenomena from very short (millimeter) to very long (solar system) distance scales.

Am I the only one who finds these attempts to account for gravity as a manifestation of more or less conventional late 20th century quantum field theory (QFT) to be desperately contrived, if not simply obtuse? The most profound fact about gravity implied by GR is that it is not in any conventional sense a force at all. It arises from the structure of spacetime, which is in turn a dynamic function of the distribution of energy (aka, mass-energy) within it. This is what sets it apart. QFT needs to be formulated in spacetime. Altering the formulation to be compatible with a spacetime background that is curved and dynamical is a tricky act to pull off, and raises deep questions about the foundations of QFT itself, notwithstanding considerable practical success (as applied in certain areas of astrophysics).

Of course, one can choose not to take “gravity as geometrodynamics” that seriously. This seems to be the stance repeatedly adopted by particle physicists and some condensed matter physicists who have taken an interest in general relativity and cosmology. Even string theory began this way, although it has ended up undermining the assumption that gravity is a particle interaction or a side effect of other interactions in the context of QFT. The outcomes of these attempts may well offer clues, but ultimately the basic questions of principle need to be confronted directly.

http://arxiv.org/pdf/hep-ph/0703263v1
http://www-boone.fnal.gov/slides-talks/conf-talk/tayloe/RT_CPT07.pdf

Yet this paper is dealing with massive neutrinos

My understanding was that one of the most “intuitive” arguments against lorentz violation was the potential for second law violations around a black hole

http://arxiv.org/pdf/hep-th/0603158v2

I’m probably not sophisticated enough to understand all the nuances of these arguments, but I would certainly love to hear more.