Here, have a coupla ligatures: Æ & æ.

k_ak^a = m^2 + A(k_5)^2, a = 1, 2, 3, 4,

where the k_5 is the bit that propagates into some additional dimension which involves the ether. I am thinking that the Lorentz invariance is violated because this additional dimension under a symmetry breaking acts as a mass-like term. This might then be an ether if k_5 = k_5(k_a) which gives a preferred coordinate condition in the universe or spacetime. The A term above might be some term from a Higgs type of field.

If this sort of thing happened to my mind there is some preferred frame for the Higgs field to give mass to particles and it would appear to give a preferred direction for the propagation of light as well. I have not thought enough about this, but this would seem to imply a different type of Higgs field than what we are familiar with.

Lawrence B. Crowell

See also: http://arxiv.org/abs/astro-ph/0703783 “Natural Dark Energy”, which proposes to squat on ‘sextessence’, ‘septessence’, etc.

I am trying to figure out the difference between the stuff we’ve done and these papers. In my thesis, I worked out the constraints on the (b1,b2,b3) (equivalent to your (alpha,1) parameter set with b1=-b3), using stability and boundedness of Hamiltonian of the spin-0,1,2 components of the vector-tensor spectra.

In particular, I showed that we need b2>0, which I think is equivalent to saying that alpha=-1 (since we are allowed to rescale it as your set of parameters is one less than the old one). But here, you are saying that (?) there is only 1 unique choice *only* if we impose the additional condition that we want the vector to be not superluminal in all frames, which you showed by considering the space of all possible lorentz boosts of the vector. My question is that : the calculation that Ted+David did (and we did in the old papers for dS space) is “manifestly lorentz invariant”, i.e. it’s written with well behaved lorentz indices. The constraints that was derived by us seems, as far as I can understand, lorentz invariant. So I am not sure what is the additional ingredients you have put in??

(Sorry if I am rambling a little bit!)

The Higgs, or scalars more generally, just don’t do the trick, as a scalar with a nonzero expectation value is still Lorentz-invariant — you can’t measure your speed with respect to it.

The CMB provides an approximate rest frame for the universe, but only in the same sense as the Earth provides a preferred notion of “up” and “down.” What we’re looking for here is symmetry breaking in the vacuum, not just because there is some “stuff” hanging around with respect to which we can measure our speed.