Reduction of quantum noise and increase of amplification of gravitational waves signals in Michelson interferometer by the use of squeezed states

TL;DR

This paper demonstrates that injecting squeezed vacuum states into a Michelson interferometer can reduce quantum noise and enhance gravitational wave signal amplification, with a new method increasing photon number expectation while reducing noise.

Contribution

It introduces a novel method to increase photon number expectation and reduce noise in gravitational wave detectors using squeezed states, correcting previous sign errors.

Findings

Quantum noise can be reduced with squeezed states.

Photon number expectation can be increased while decreasing standard deviation.

The main physical effect remains despite previous sign errors.

Abstract

It is shown in the present Letter that the quantum noise due to high laser intensities in Michelson interferometer for gravitational waves detection can be reduced by sending squeezed vacuum states to the 'dark' port of the interferometer. The experimental details of such physical system have been described in a recent article by Barak and Ben-Aryeh (JOSA-B, 25, 361(2008)). In another very recent article by Voronov and Weyrauch (Phys. Rev.A 81, 053816 (2010)) they have followed our methods for treating the same physical system, and have pointed out an error in the sign of one of our expressions thus claiming for the elimination of our physical results. I show here a method by which the expectation value for the photon number operator is increased and at the same time the standard deviation is reduced. Although due to the mistake in sign in our expression the physical method for obtaining such result is different from our original study [1], the main physical effect can remain .