StarMountainKid, on 12 September 2012 - 06:26 PM, said:
I'm a little confused on these points. In the first quote, does this mean that, because a homogenious universe without dark matter/dark energy is unstable, dark matter/dark energy is spontaneously created?
I am not an expert in this sort of thing, but I think it the authors are suggesting that dark matter/dark energy are results of spontaneous
polarization rather than spontaneous
creation.
In other words, I think the authors are saying there is no such thing as dark matter/dark energy (in a classical sense, anyway), only negative or positive amplitudes of this underlying scalar field.
I have not studied the article, but I think the authors suggest that the
total amplitude of this scalar field (over the entire Universe) is and always has been a constant, but locally it may be positive (dark matter-like, i.e. in the halos of galaxies) or negative (dark energy-like, i.e. in between galaxies).
One analogue to this is electromagnetism: the current argument is that the Universe has a magnetic field that reaches everywhere, however in most places this field is close to zero. If you turn on an electromagnet you don't
spontaneously create a magnetic field, rather you
spontaneously polarize the magnetic field: creating a region that is positive (at one end of the magnet) and negative (at the other end).
StarMountainKid, on 12 September 2012 - 06:26 PM, said:
And likewise, in the second quote, souldn't it read, "new type of energy/force causes the nonuniform distribution of matter in the universe", and not "the nonuniform distribution of matter in the universe causes the new type of energy/force"?
I don't think so... (Again, I have not studied the paper in depth so this may be wrong)
Because the scalar field has positive and negative parts, it is able to balance itself. Therefore, a homogeneous equilibrium (for just this scalar field, anyway) is stable.
Gravity is mutually attractive, however, so once matter starts forming clumps the tendency is to form larger clumps rather than smooth back out (so in contrast, a homogeneous equilibrium of matter is unstable under gravity alone).
So I think once matter started to form clumps under gravity, this caused the scalar field to start deviating from equilibrium (which of course has an effect on matter and gravity, which of course leads to more deviations in the field, etc.).