Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

[Phys-l] Emergent Electroweak Gravity




This paper runs along the lines that I have posted on, in particular the
notion that gravity emerges at a much lower energy scale than the Planck
scale. In String theory gravity is emergent in a way that evades the Witten
Weinberg theorem by quantizing geometry. But if gravity is to emerge at a
much lower scale we must abandon diffeomorphism invariance as an exact
symmetry of nature. This possibility is suggested , in my opinion , by the Grid
model proposed by Wilczek ( The Lightness of Being) where space time might
emerges at the Planck scale, the Planck grid, but gravity emerges at a
lower scale due to local variability of
the action density the Zero point fluctuations of the quantum fields in
the presence of concentrations of mass energy, Sakharov's induced gravity.
The graviton then is a result of the collective excitation of the quantum
fields and IS background dependent. Diffeomorphism invariance is an emergent
property, not a fundamental symmetry. This is pretty radical but perhaps
worth some consideration.

Bob Zannelli

))))))))))))))))))))))))))))))))

Emergent Electroweak Gravity
Authors: _Bob McElrath_
(http://arxiv.org/find/gr-qc/1/au:+McElrath_B/0/1/0/all/0/1)
(Submitted on 15 Dec 2008)

Abstract: We show that any massive cosmological relic particle with small
self-interactions is a super-fluid today, due to the broadening of its wave
packet, and lack of any elastic scattering. The WIMP dark matter picture
is only consistent its mass $M \gg M_{\rm Pl}$ in order to maintain
classicality. The dynamics of a super-fluid are given by the excitation spectrum of
bound state quasi-particles, rather than the center of mass motion of
constituent particles. If this relic is a fermion with a repulsive interaction
mediated by a heavy boson, such as neutrinos interacting via the $Z^0$, the
condensate has the same quantum numbers as the vierbein of General
Relativity. Because there exists an enhanced global symmetry
$SO(3,1)_{space}\times SO(3,1)_{spin}$ among the fermion's self-interactions broken only by its
kinetic term, the long wavelength fluctuation around this condensate is a
Goldstone graviton. A gravitational theory exists in the low energy limit of
the Standard Model's Electroweak sector below the weak scale, with a
strength that is parametrically similar to $G_N$.


))))))))))))))))))))))))))))

_http://arxiv.org/PS_cache/arxiv/pdf/0812/0812.2696v1.pdf_
(http://arxiv.org/PS_cache/arxiv/pdf/0812/0812.2696v1.pdf)