Comment on "Relativistic Effects of Light in Moving Media with Extremely Low Group Velocity"

TL;DR

This paper critiques previous theoretical models of optical black holes created in flowing dielectric media, clarifying that certain proposed geometries do not actually form true black holes.

Contribution

It identifies a subtle misinterpretation in earlier analyses, clarifying the conditions under which optical black holes can or cannot exist.

Findings

Certain geometries claimed as optical black holes are not true black holes.

Theoretical prospects for creating optical black holes are promising, but specific models need correction.

Clarifies the distinction between theoretical constructs and actual black hole formation in optical media.

Abstract

In [cond-mat/9906332; Phys. Rev. Lett. 84, 822 (2000)] and [physics/9906038; Phys. Rev. A 60, 4301 (1999)] Leonhardt and Piwnicki have presented an interesting analysis of how to use a flowing dielectric fluid to generate a so-called "optical black hole". Qualitatively similar phenomena using acoustical processes have also been much investigated. Unfortunately there is a subtle misinterpretation in the Leonhardt-Piwnicki analysis regarding these "optical black holes": While it is clear that "optical black holes" can certainly exist as theoretical constructs, and while the experimental prospects for actually building them in the laboratory are excellent, the particular model geometries that Leonhardt and Piwnicki write down as alleged examples of "optical black holes" are in fact not black holes at all.