Measuring Gravito-magnetic Effects by Multi Ring-Laser Gyroscope

TL;DR

This paper proposes an underground multi-ring laser gyroscope experiment to measure Earth's relativistic effects, like frame dragging, with high precision over two years, using large, symmetrically arranged ring-lasers.

Contribution

It introduces a novel multi-ring laser system configuration and analysis method to detect Earth's gravito-magnetic effects with improved stability and accuracy.

Findings

Achieves 1% sensitivity for Lense-Thirring effect detection

Designs symmetric ring-laser configurations for stability

Estimates two-year measurement feasibility with 6 m rings

Abstract

We propose an under-ground experiment to detect the general relativistic effects due to the curvature of space-time around the Earth (de Sitter effect) and to rotation of the planet (dragging of the inertial frames or Lense-Thirring effect). It is based on the comparison between the IERS value of the Earth rotation vector and corresponding measurements obtained by a tri-axial laser detector of rotation. The proposed detector consists of six large ring-lasers arranged along three orthogonal axes. In about two years of data taking, the 1% sensitivity required for the measurement of the Lense-Thirring drag can be reached with square rings of 6 $m$ side, assuming a shot noise limited sensitivity ($ 20 prad/s/\sqrt{Hz}$). The multi-gyros system, composed of rings whose planes are perpendicular to one or the other of three orthogonal axes, can be built in several ways. Here, we consider cubic and octahedron structures. The symmetries of the proposed configurations provide mathematical relations that can be used to study the stability of the scale factors, the relative orientations or the ring-laser planes, very important to get rid of systematics in long-term measurements, which are required in order to determine the relativistic effects.