1105.6310 (Ángel Rivas et al.)

Sub-Heisenberg estimation of non-random phase-shifts    [PDF]

Ángel Rivas, Alfredo Luis

We provide evidence that the uncertainty in detection of small and deterministic phase-shift deviations from a working point can be lower than the Heisenberg bound, for fixed finite mean number of photons. We achieve that by exploiting non-linearity of estimators and coherence with the vacuum.

View original: http://arxiv.org/abs/1105.6310