What is wrong with the interpretation of recent nano-filament experiments?

TL;DR

This paper critically examines recent nano-filament experiments, providing an alternative analysis that suggests the observed deformations are due to a pulling force, challenging previous interpretations of photon momentum.

Contribution

It offers a new numerical approach considering full electromagnetic forces, disputing the conclusion that photons carry Abraham momentum inside the filament.

Findings

Net force on nano-filament end face is a pull, not a push.

Previous interpretation of photon momentum in the filament is challenged.

Comprehensive force calculations alter understanding of light-matter interaction in nano-filaments.

Abstract

In a recent paper, W. She, J. Yu and R. Feng reported the slight deformations observed upon transmission of a light pulse through a short length of a silica glass nano-filament. Relating the shape and magnitude of these deformations to the momentum of the light pulse inside and outside the filament, these authors concluded that, within the fiber, the photons carry the Abraham momentum. We present an alternative evaluation of force and momentum in a system similar to the experimental setup of She et al. Using precise numerical calculations that take into account not only the electromagnetic momentum inside and outside the filament, but also the Lorentz force exerted by a light pulse in its entire path through the nano-waveguide, we conclude that the net effect should be a pull (rather than a push) force on the end face of the nano-filament.