Can gravitational microlensing by vacuum fluctuations be observed?

TL;DR

This paper investigates whether vacuum quantum fluctuations can cause observable gravitational microlensing, concluding that direct detection is unlikely but cumulative effects over cosmological distances might be detectable, providing a potential test for TeV-scale gravity.

Contribution

It analyzes the potential for observing gravitational microlensing caused by vacuum fluctuations and assesses the feasibility of detecting such effects.

Findings

Microlensing effects become significant at scales larger than the Planck length.

Direct observation of these fluctuations remains unlikely.

Cumulative effects over cosmological distances could be detectable.

Abstract

Although the prospect is more plausible than it might appear, the answer to the title question is, unfortunately, "probably not." Quantum fluctuations of vacuum energy can focus light, and while the effect is tiny, the distribution of fluctuations is highly non-Gaussian, offering hope that relatively rare "large" fluctuations might be observable. I show that although gravitational microlensing by such fluctuations become important at scales much larger than the Planck length, the possibility of direct observation remains remote, although there is a small chance that cumulative effects over cosmological distances might be detectable. The effect is sensitive to the size of the Planck scale, however, and could offer a new test of TeV-scale gravity.