Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

Effective Null Raychaudhuri Equation

Version 1 : Received: 24 September 2018 / Approved: 24 September 2018 / Online: 24 September 2018 (17:09:46 CEST)

A peer-reviewed article of this Preprint also exists.

Pesci, A. Effective Null Raychaudhuri Equation. Particles 2018, 1, 230-237. Pesci, A. Effective Null Raychaudhuri Equation. Particles 2018, 1, 230-237.


The effects on Raychaudhuri's equation of an intrinsically discrete or particle nature of spacetime are investigated, through consideration of null congruences emerging from, or converging to, a generic point of spacetime, i.e. in geometric circumstances somehow prototypical of singularity issues. This is done from an effective point of view, meaning through a (continuous) description of spacetime modified to embody the existence of an intrinsic discreteness on the small scale, adding to previous results for non-null congruences. Various expressions for the effective rate of change of expansion are derived. They in particular provide finite values for the limiting effective expansion and its rate of variation when approaching the focal point; this on top of resulting non vanishing the limiting cross-sectional area itself of the congruence.


Raychaudhuri equation; atoms of spacetime


Physical Sciences, Space Science

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