Comment on: Hawking Radiation from Ultrashort Laser Pulse Filaments

TL;DR

This paper critically examines a recent claim of observing Hawking radiation analog in laser pulse experiments, arguing that the evidence is insufficient and the phenomenon is not conclusively demonstrated.

Contribution

It provides a critical commentary questioning the interpretation of experimental results as Hawking radiation analogs in optical systems.

Findings

The observed radiation's cause remains unclear.

The experimental setup does not definitively demonstrate Hawking effect.

The paper challenges the attribution of the observed radiation to Hawking analogs.

Abstract

In a recent paper Belgiorno {\em et al} claimed to have observed the analog of the Hawking effect because of the detection of radiation in a frequency range in which what they called "phase horizons" existed. They created rapidly moving pulses of light in a silica glass whose Kerr effect altered the refractive index to create those horizons. Unfortunately, while the observations are very interesting, the cause of the radiation is not understood, and we feel it is not justified to call this a detection of the Hawking effect in an analog system.