Twin beam quantum-enhanced correlated interferometry for testing fundamental physics

Abstract

Quantum metrology deals with improving the resolution of instruments that are otherwise limited by shot noise and it is therefore a promising avenue for enabling scientific breakthroughs. The advantage can be even more striking when quantum enhancement is combined with correlation techniques among several devices. Here, we present and realize a correlation interferometry scheme exploiting bipartite quantum correlated states injected in two independent interferometers. The scheme outperforms classical analogues in detecting a faint signal that may be correlated/uncorrelated between the two devices. We also compare its sensitivity with that obtained for a pair of two independent squeezed modes, each addressed to one interferometer, for detecting a correlated stochastic signal in the MHz frequency band. Being the simpler solution, it may eventually find application to fundamental physics tests, e.g., searching for the effects predicted by some Planck scale theories.

An experiment for observing quantum gravity phenomena using twin table-top 3D interferometers

“…This approach theoretically increases the sensitivity in the cross-spectrum of the two interferometers beyond the photon shot noise limit as encountered using two independent squeezed states [72]. Recently, entangled squeezing was successfully demonstrated in two isolated Michelson interferometers [73]. Although in this research the use of a single entangled squeezed state did not provide an improvement over independent squeezed states, this result shows the advantages of using various non-classical states of light in measuring correlated signals in interferometers.…”

“…, n bin }, where the total number of bins n bin is determined by the correlation bandwidth B C xy and the length of individual spectra T DFT . The noise cross power spectral density is the geometric mean of the noise auto power spectral densities in the individual interferometers (N xx , N yy ), and decreases over time with the square root of the number of measured spectra n spec = T int /T DFT [34,73], i.e.…”

Direct limits for scalar field dark matter from a gravitational-wave detector

“…Moreover, by slightly modifying the optics in such interferometers—for example, by using mirrors of different thicknesses in each interferometer arm—their sensitivity to scalar field dark matter could be improved further 16 . Through the reduction of losses, quantum technologies such as squeezed light are also expected to improve, allowing for increasing noise mitigation 44 . These and other future technological advances make precision interferometers operating beyond quantum limits indispensable tools for dark matter detection and fundamental physics in general.…”

Quantum conformance test

“…Substantial progress has been made in recent years in the field of quantum sensing ( 1 , 2 ) both for continuous parameter estimation ( 3 – 5 ) and for discrimination tasks in the case of discrete variables ( 6 – 8 ). The use of quantum states and resources brings an advantage that has been demonstrated in various specific tasks: both phase ( 9 – 13 ) and loss ( 14 – 20 ) estimation, quantum imaging ( 21 – 23 ), and discrimination protocols such as target detection ( 24 – 27 ) and quantum reading ( 28 , 29 ).…”