Graviton Ques?
WG
scovered],,,,,
Would gravitons [wavelength] undergo a red or blueshift if the 2 interactin=
g masses were moving away or towards each other at high speeds?
As opposed to 2 interacting masses which are stationary wrt each other.
WG
WG
di=3D
> scovered],,,,,
>
> Would gravitons [wavelength] undergo a red or blueshift if the 2 interact=
in=3D
> g masses were moving away or towards each other at high speeds?
> As opposed to 2 interacting masses which are stationary wrt each other.
>
> WG
The answer appears to be yes, as they would be the same as photons in this =
respect.
Does this not suggest a possible experimental test between GR and QM as to =
which is the correct interpretation of gravity ?
As you know QM and GR are presently incompatible wrt gravity.
-Under GR,,, gravity is explained as a curvature of space-time, i.e. non Eu=
clidean geometry [Riemannian geometry, geodesics etc.]
-Under QM,,, gravity is explained as a transfer of the gravity force boson =
[graviton].
These 2 explanations are at odds with each other.
If you have 2 given masses initially at rest separated by dist R. [emphasis=
on rest]
They will accelerate towards each other according to the Newtonian approxim=
ations F=3Dma and F=3DG M1M2/R^2. This is true under both QM and GR.
However consider 2 masses traveling towards each other at a high rate of sp=
eed.
Under GR one would a expect F=3DG M1M2/R^2 to hold true for all speeds, sin=
ce geometry should not effect the calculation.
Under QM however the gravitons would be blue shifted towards a higher energ=
y, which would manifest itself as a higher energy graviton, [more attractio=
n than in the rest state] thus a small departure from F=3DG M1M2/R^2 should=
be observed.
i.e. Under QM the gravitons energy would be different in the 2 cases [low v=
elocity and high velocity] resulting in different accelerations for the sam=
e 2 masses, yet under GR they should be the same!
Has anyone looked ?
This is certainly true for red or blueshifted light photons when interactin=
g in some process, why not gravitons ?
This would be an extremely small effect at the limits of experiment, but do=
able.
Someone should look !!!
WG
carlip...@physics.ucdavis.edu
> While I am aware that gravitons are still hypothetical under QM [not yet =
di=3D
> scovered],,,,,
> Would gravitons [wavelength] undergo a red or blueshift if the 2 interact=
in=3D
> g masses were moving away or towards each other at high speeds?
> As opposed to 2 interacting masses which are stationary wrt each other.
"Real" gravitons -- the quanta of gravitational waves -- would be red-
or blue-shifted.
When a quantum theory describes an interaction as coming from the
exchange of quanta (photons, gravitons, etc.), though, the quanta
being exchanged are "virtual" particles. The effect of motion on
virtual gravitons is much more subtle, in part because the virtual
gravitons responsible for interactions come with all possible energies
and frequencies. At low energies, the effects can be computed, though
it's not easy. The results agree with the predictions of classical
general relativity (in which gravitational interactions also depend
on relative velocities), up to very tiny corrections.
Steve Carlip