A common misconception about LIGO detectors of gravitational waves

TL;DR

This paper clarifies a misconception about LIGO detectors, explaining that gravitational waves do produce observable effects despite the stretching of laser wavelength and arm length, through direct calculation.

Contribution

It provides a clear correction to the misconception by performing a direct calculation demonstrating the detectability of gravitational waves.

Findings

Gravitational waves cause measurable effects in LIGO detectors.

The misconception about no observable effect is incorrect.

Direct calculations confirm the detectability of gravitational waves.

Abstract

A common misconception about laser interferometric detectors of gravitational waves purports that, because the wavelength of laser light and the length of an interferometer's arm are both stretched by a gravitational wave, no effect should be visible, invoking an analogy with cosmological redshift in an expanding universe. The issue is clarified with the help of a direct calculation.