Experimental Gravity, Gravitational Waves, and Quantum Nondemolition: An Introduction

Vladimir B. Braginskii, Iu. I. Vorontsov, K. S. Thorne

A. Camacho

Partha Nandi, Bibhas Ranjan Majhi, Debnath, Nandita +1 more

Recent proposals are emerging for the experimental detection of entanglement mediated by classical gravity, carrying significant theoretical and observational implications. In fact, the detection of gravitational waves (GWs) in LIGO provides an alternative laboratory for testing various gravity-related properties. By employing LIGO's arms as oscillators interacting with gravitational waves (GWs), our study demonstrates the potential for generating quantum entanglement between two mutually orthogonal modes of simple harmonic oscillators. Our findings reveal unique entanglement dynamics, including periodic "collapse and revival" influenced by GW oscillations, alongside a distinct "quantum memory effect." Effectively, each harmonic oscillator feels a temperature. We believe that these forecasts may hold significance towards both theoretically probing and experimentally verifying various properties of classical gravitational waves.

Yu. Levin

A new optical topology and signal readout strategy for a laser interferometer gravitational wave detector were proposed recently by Braginsky and Khalili. Their method is based on using a nonlinear medium inside a microwave oscillator to detect the gravitational-wave-induced spatial shift of the interferometer's standing optical wave. This paper proposes a quantum nondemolition scheme that could be realistically used for such a readout device and discusses a ``fundamental'' sensitivity limit imposed by a higher order optical effect.

Abel Camacho

In the present work the detection, by means of a nondemolition measurement, of a Yukawa term, coexisting simultaneously with gravity, has been considered. In other words, a nondemolition variable for the case of a particle immersed in a gravitational field containing a Yukawa term is obtained. Afterwards the continuous monitoring of this nondemolition parameter is analyzed, the corresponding propagator is evaluated, and the probabilities associated with the possible measurement outputs are found. The relevance of these kind proposals in connection with some unified theories of elementary particles has also been underlined.

Pierre Meystre, Marlan O. Scully