English

A Casimir cannot cavity fly

General Relativity and Quantum Cosmology 2015-02-10 v3

Abstract

The field inside a Casimir cavity has an effective negative mass, which acts as a buoyancy force in a gravitational field. Can this render the total mass of the cavity negative, making it "float" in the vacuum ? Recent theoretical arguments indicate that this is impossible. We provide support to this conclusion discussing a concrete simple model of cavity, with plane parallel metallic plates kept in mechanical equilibrium by a spring and placed in a weak gravitational field. We show that basic facts about the structure of matter imply that the total mass of the cavity is always positive. This has implications for the hypothetical relation between vacuum energy and cosmological constant.

Cite

@article{arxiv.1406.1105,
  title  = {A Casimir cannot cavity fly},
  author = {Massimo Cerdonio and Carlo Rovelli},
  journal= {arXiv preprint arXiv:1406.1105},
  year   = {2015}
}

Comments

misprints in formulas amended; references added; english refurbished; no change in substance

R2 v1 2026-06-22T04:30:43.469Z