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arXiv · 2506.17149

Fully Self-Consistent Semiclassical Gravity

R. Muciño·E. Okon·D. Sudarsky·M. Wiedemann
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Abstract

A theory of quantum gravity consists of a gravitational framework which, unlike general relativity, takes into account the quantum character of matter. In spite of impressive advances, no fully satisfactory, self-consistent and empirically viable theory with those characteristics has ever been constructed. A successful semiclassical gravity model, in which the classical Einstein tensor couples to the expectation value of the energy-momentum tensor of quantum matter fields, would, at the very least, constitute a useful stepping stone towards quantum gravity. However, not only no empirically viable semiclassical theory has ever been proposed, but the self-consistency of semiclassical gravity itself has been called into question repeatedly over the years. Here, we put forward a fully self-consistent, empirically viable semiclassical gravity framework, in which the expectation value of the energy-momentum tensor of a quantum field, evolving via a relativistic objective collapse dynamics, couples to a fully classical Einstein tensor. We present the general framework, a concrete example, and briefly explore possible empirical consequences of our model.

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R. Muciño, E. Okon, D. Sudarsky, M. Wiedemann. 2025-06-20. Fully Self-Consistent Semiclassical Gravity. https://arxiv.org/abs/2506.17149

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