Publications (7)
Certified quantum non-demolition measurement of a macroscopic material system
R. J. Sewell, M. Napolitano, N. Behbood +2
Quantum non-demolition (QND) measurements improve sensitivity by evading measurement back-action. The technique was first proposed to detect mechanical oscillations in gravity wave…
Efficient quantification of non-Gaussian spin distributions
B. Dubost, M. Koschorreck, M. Napolitano +3
We study theoretically and experimentally the quantification of non-Gaussian distributions via non-destructive measurements. Using the theory of cumulants, their unbiased estimator…
Interaction-based quantum metrology showing scaling beyond the Heisenberg limit
M. Napolitano, M. Koschorreck, B. Dubost +3
Quantum metrology studies the use of entanglement and other quantum resources to improve precision measurement. An interferometer using N independent particles to measure a paramet…
Feedback-cooling of an atomic spin ensemble
N. Behbood, M. Napolitano, G. Colangelo +4
We describe a measurement-and-feedback technique to deterministically prepare low-entropy states of atomic spin ensembles. Using quantum non-demolition measurement and incoherent o…
Ultrasensitive Atomic Spin Measurements with a Nonlinear Interferometer
R. J. Sewell, M. Napolitano, N. Behbood +3
We study nonlinear interferometry applied to a measurement of atomic spin and demonstrate a sensitivity that cannot be achieved by any linear-optical measurement with the same expe…
Generation of macroscopic singlet states in a cold atomic ensemble
N. Behbood, F. Martin Ciurana, G. Colangelo +4
We report the generation of a macroscopic singlet state in a cold atomic sample via quantum non-demolition (QND) measurement induced spin squeezing. We observe 3 dB of spin squeezi…
Magnetic sensitivity beyond the projection noise limit by spin squeezing
R. J. Sewell, M. Koschorreck, M. Napolitano +3
We report the generation of spin squeezing and entanglement in a magnetically-sensitive atomic ensemble, and entanglement-enhanced field measurements with this system. A maximal Ra…