# Violation of the EP

## Main Question or Discussion Point

"Violation of the equivalence principle for stressed bodies in asynchronous relativity"

This is the abstract of a paper that appears to relate to a lot of the issues discussed recently in this forum:

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Summary In the recently developed asynchronous formulation of the relativistic theory of extended bodies, the inertial mass of a body does not explicitly depend on its pressure or stress. The detailed analysis of the weight of a box filled with a gas and placed in a weak gravitational field shows that this feature of asynchronous relativity implies a breakdown of the equivalence between inertial and passive gravitational mass for stressed systems.
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I do not have access to the article (pay per view). Is there anyone who does have access that can tell us the gist of the article?

Related Special and General Relativity News on Phys.org
Not at the moment. Perhaps this will interest you.
http://relativity.livingreviews.org/open?pubNo=lrr-2006-3&page=title.html [Broken]

Last edited by a moderator:
Mentz114
Gold Member
Anyone got $32 ? Edit: Thought about this more at lunch... It seems that their argument is that since it is taken that stresses must add to gravitational mass (as per the stress-energy tensor of General Relativity), but that the inertial mass was not found to increase, they mustn't be the same thing. Of course, the only way to have truly tested this was to verify that the stresses did increase the gravitational mass, and thus the resulting gravitational field. That is kind of interesting in a way. Last edited: Anyone got$32 ?
Well, some university students and people in scientific institutes get free access to this sort of material. I assumed some of the members of PF would be in that catagory?

"Violation of the equivalence principle for stressed bodies in asynchronous relativity"

This is the abstract of a paper that appears to relate to a lot of the issues discussed recently in this forum:

=================================================================
Summary In the recently developed asynchronous formulation of the relativistic theory of extended bodies, the inertial mass of a body does not explicitly depend on its pressure or stress. The detailed analysis of the weight of a box filled with a gas and placed in a weak gravitational field shows that this feature of asynchronous relativity implies a breakdown of the equivalence between inertial and passive gravitational mass for stressed systems.
=================================================================

I do not have access to the article (pay per view). Is there anyone who does have access that can tell us the gist of the article?
Without reading that article I will say this. Even for a box containing a gas whose pressure is finite the entire box-gas system is related to its total inertia mass by E = mc^2 and its weight is W = mg where m = inertial mass of the box-gas system. The reason that the pressure does not appear in those expressions if that it refers to the mass of the system which includes the box. One then has to include the stress in the walls of the box to find the total mass. This stress exactly cancels the pressure of the gas and thus only the mass-energy contributes to the inertial mass (and hence the passive gravitational mass) of the system.

For details please see - http://arxiv.org/abs/physics/0609144

Pete