How Does Casimir Energy Fall?

TL;DR

This paper demonstrates that Casimir energy gravitates according to the equivalence principle, confirming that its inertial and gravitational masses are both E_c/c^2, thus addressing longstanding doubts about quantum vacuum energy's gravitational effects.

Contribution

It provides a clear demonstration that Casimir energy obeys the equivalence principle, countering recent claims and clarifying calculation pitfalls.

Findings

Casimir energy gravitates as expected by the equivalence principle.

Inertial and gravitational masses of Casimir energy are both E_c/c^2.

Addresses and corrects misconceptions in previous literature.

Abstract

Doubt continues to linger over the reality of quantum vacuum energy. There is some question whether fluctuating fields gravitate at all, or do so anomalously. Here we show that for the simple case of parallel conducting plates, the associated Casimir energy gravitates just as required by the equivalence principle, and that therefore the inertial and gravitational masses of a system possessing Casimir energy $E_c$ are both $E_c/c^2$. This simple result disproves recent claims in the literature. We clarify some pitfalls in the calculation that can lead to spurious dependences on coordinate system.