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Dr. Mario Napolitano

ICFO, Barcelona (Spain)

Thursday, March 1st, 2012 at 02:30:00 PM  

Conference room Querzoli - LENS - via Nello Carrara 1 - Sesto Fiorentino (Florence)

Published on-line at 02:47:05 PM on Tuesday, February 28th, 2012

Quantum metrology with cold atomic ensembles

Quantum metrology, that is analysis and exploitation of quantum correlations among particles beyond quantum limits in sensitivity of measurement instruments.

The technological advance is continuously improving the performances of the most sensitive measurement instruments. Devices as clocks for time-standards, magnetometers, gravimeters or even gravitational antennas, are very close to be limited in sensitivity simply by the quantum nature of its constituents. At this point is where quantum metrology becomes important.

The community of scientists during the last decades worked in developing and demonstrating the importance of quantum correlations among particles, i.e., entanglement or squeezing, for enhanced measurement sensitivity. However, such resources are very fragile and sometimes they cannot be used. Moreover, a debate rose up recently about a possible alternative strategy making use of direct interaction between probing particles.

With our experimental apparatus we could investigate both the strategies: using ensembles of cold rubidium atoms we obtained the first magnetic-sensitive squeezing state in a larger-than-spin ½ system. Also we performed the first experimental demonstration of interactions and nonlinear dynamics for relevant use in quantum metrology: we found that the order of nonlinearity due to the interactions translates in a scaling of sensitivity better than the Heisenberg limit, which we observed for about two orders of magnitude.

[video=720 538]20120301_napolitano[/video]

For further informations, please contact Prof. Francesco S. Cataliotti.