Certified quantum non-demolition measurement of material systems

M W Mitchell, M Koschorreck, M Kubasik, M Napolitano, R J Sewell
2012 New Journal of Physics  
An extensive debate on quantum non-demolition (QND) measurement, reviewed in Grangier et al. [Nature, {\bf 396}, 537 (1998)], finds that true QND measurements must have both non-classical state-preparation capability and non-classical information-damage tradeoff. Existing figures of merit for these non-classicality criteria require direct measurement of the signal variable and are thus difficult to apply to optically-probed material systems. Here we describe a method to demonstrate both
more » ... strate both criteria without need for to direct signal measurements. Using a covariance matrix formalism and a general noise model, we compute meter observables for QND measurement triples, which suffice to compute all QND figures of merit. The result will allow certified QND measurement of atomic spin ensembles using existing techniques.
doi:10.1088/1367-2630/14/8/085021 fatcat:jnpyscwykjgmbmqqsr7shmbooe