In both quantum and general relativity theories we are used to provide results in the "limited" conditions to demonstrate a correspondence between new and old formalism.(adsbygoogle = window.adsbygoogle || []).push({});

For instance deflection of light of a star due to Sun in GR is double the amount given in classical theory.

Yet I have problems to sense a limit condition on the gravity due to pure radiation also called null dust solution of Einstein's field equation for a perfect pressureless fluid.

If we tend to zero both the masses on the Newtown gravity law the force among the objects/particles will be zero.

But based on Einstein's field equation the energy momentum tensor does not vanish in the case of massless objects and is defined in terms of two null four velocities which is the equation for a dust with zero pressure. Therefore the nonvanishing curvature tensor says that a group of massless particles have gravity among themselves.

Is this a correct understanding?

And is it a counter example to correspondence principal in GR?

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# Breakdown of correspondence principle: null dust case

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