Quantum-Dense Metrology [article]

Sebastian Steinlechner, Jöran Bauchrowitz, Melanie Meinders, Helge Müller-Ebhardt, Karsten Danzmann, Roman Schnabel
2012 arXiv   pre-print
Quantum metrology utilizes entanglement for improving the sensitivity of measurements. Up to now the focus has been on the measurement of just one out of two non-commuting observables. Here we demonstrate a laser interferometer that provides information about two non-commuting observables, with uncertainties below that of the meter's quantum ground state. Our experiment is a proof-of-principle of quantum dense metrology, and uses the additional information to distinguish between the actual
more » ... signal and a parasitic signal due to scattered and frequency shifted photons. Our approach can be readily applied to improve squeezed-light enhanced gravitational-wave detectors at non-quantum noise limited detection frequencies in terms of a sub shot-noise veto-channel.
arXiv:1211.3570v1 fatcat:go5dld2z4fempiw5jbxi6ihaku