---
title: "Semiclassical gravity"
type: "entity"
entity_kind: "concept"
status: "hub"
canonical_name: "Semiclassical gravity"
aliases: ["quantum field theory on curved spacetime","QFT on curved spacetime"]
first_seen: "2026-10-11T00:00:00.000Z"
writer_model: "claude-sonnet-5"
connects_to: ["trace anomaly","renormalization (quantum field theory)","gravitational stress-energy tensor","general relativity","quantum gravity (contrast)"]
seek_code_commit: "d40ee39"
---


Semiclassical gravity is the framework in which spacetime's metric stays a
classical field, governed by Einstein's equations with a source term, while
the matter fields living on that spacetime are quantized — a deliberate
halfway house short of full quantum gravity, where the metric itself would
also be quantized. It is the setting for the [[entity-trace-anomaly|trace
anomaly]], Hawking radiation, cosmological particle creation, and the
Drummond-Hathrell vacuum-polarization effect, among other results that have
no classical analogue.

The vault met this framework through Antonio Ferreiro and Andrea Cavallaro's
2026 preprint (arXiv:2610.10588), which argues that quantizing
matter fields in this framework — without touching gravity itself — is enough
to break a non-existence theorem [[entity-erik-curiel|Curiel]] proved
classically
([[claim-ferreiro-cavallaro-2026-qft-renormalization-yields-gravitational-stress-energy-tensor]]),
and builds two further philosophical readings of general relativity on top of
that result
([[claim-ferreiro-cavallaro-2026-metric-gains-material-significance-egalitarian-reading]],
[[claim-ferreiro-cavallaro-2026-unificationist-dilemma-matter-spacetime-divide]]).
This is the vault's first claim-note cluster in this specific subfield of
physics.

## References
- [[claim-ferreiro-cavallaro-2026-qft-renormalization-yields-gravitational-stress-energy-tensor]]
- [[claim-ferreiro-cavallaro-2026-metric-gains-material-significance-egalitarian-reading]]
- [[claim-ferreiro-cavallaro-2026-unificationist-dilemma-matter-spacetime-divide]]
- Capture: 10-inbox/raw/2026-10-09-outside-arxiv261010588-when-quantum-field-theory-kicks-in.md

## Log
- 2026-10-11: Page created on promotion of the arXiv:2610.10588 capture — the vault's first contact with semiclassical gravity as a framework.