Quantum Metrology: Detection of weak forces using Schrodinger Cat resources

Abstract

We investigate the utility of non classical states of simple harmonic oscillators (a superposition of coherent states) for sensitive force detection. We find that like squeezed states a superposition of coherent states allows the detection of displacement measurements at the Heisenberg limit. Entangling many superpositions of coherent states offers a significant advantage over a single mode superposition states with the same mean photon number.

Proceedings of the Sixth International Conference on Quantum Communication, Measurement and Computing, pg 333, ed by J H Shapiro and O Hirota, Rinton Press (2003)