Measuring gravitomagnetic effects by a multi-ring-laser gyroscope

Abstract

We propose an underground experiment to detect the general relativistic effects due to the curvature of space-time around the Earth (de Sitter effect) and to the 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 triaxial 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/root Hz). The multigyros 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 octahedral structures. It is shown that the symmetries of the proposed configurations provide mathematical relations that can be used to ensure the long term stability of the apparatus

Absolute control of the scale factor in GP2 laser gyroscope: Toward a ground based detector of the lense-thirring effect

“…Thanks to its monolithic structure, where the mirrors are kept in position by optical contact on precisely tooled monolithic block of Zerodur, a glass with a "null" linear thermic expansion coefficient, G demonstrates a very high long-term stability that made possible the observation of very tiny geodetic effect, like polar motion and Chandler wobble [2]. A further increase in the angular resolution and a tri-axial gyro-system would, then, allow to reach 10 -14 rad/s; the sensitivity requested for measuring the Lense-Thirring General Relativity effect (also known as frame dragging) [3]. Such a task requires a precise control of the gyros geometry as well as a full understanding of its dynamics.…”

On Monte Carlo simulations of the LAser RElativity Satellite experiment

“…Over the years, several research groups have proposed many laboratory experiments to measure the Earth's gravitomagnetic field [6,7,9,59,8,78,75,28,27,5]. To date, none has been yet implemented.…”

A rotating Michelson interferometer from the co-rotating point of view

“…This unifying approach has been rephrased and extended by Bażański [2,3] to account for phenomena where light is also split, reflected and eventually re-converged at a point. This is the important case of interferometric experiments, such as modern tests of the isotropy of the speed of light [4], Sagnac-type interferometry [5][6][7] and Michelsontype kilometer-scale laser interferometry for gravitational waves detection [8][9][10][11]. Bażański himself re-derived the expression of the Sagnac phase shift in [2,3] and B Paolo Maraner pmaraner@unibz.it 1 School of Economics and Management, Free University of Bozen-Bolzano, Universitätsplatz-Piazzetta dell'Università 1, 39100 Bolzano-Bozen, Italy essentially his approach was used in [12] to estimate higher order corrections to the general relativistic Sagnac formula.…”