Journal of High Energy Physics (Jul 2024)

Quantum-gravitational null Raychaudhuri equation

  • Sang-Eon Bak,
  • Maulik Parikh,
  • Sudipta Sarkar,
  • Francesco Setti

DOI
https://doi.org/10.1007/JHEP07(2024)214
Journal volume & issue
Vol. 2024, no. 7
pp. 1 – 15

Abstract

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Abstract We consider a congruence of null geodesics in the presence of a quantized spacetime metric. The coupling to a quantum metric induces fluctuations in the congruence; we calculate the change in the area of a pencil of geodesics induced by such fluctuations. For the gravitational field in its vacuum state, we find that quantum gravity contributes a correction to the null Raychaudhuri equation which is of the same sign as the classical terms. We thus derive a quantum-gravitational focusing theorem valid for linearized quantum gravity.

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