Sub-Heisenberg limited phase measurement with two-mode squeezed vacuum

In this contribution, we present our studies of the sensitivity and resolution of phase measurement in a Mach-Zehnder interferometer with a two-mode squeezed vacuum (TMSV) input. TMSV provides a high-flux entangled state with average photon number of $\bar {n}$. Parity detection is suggested as a possible detection scheme, which can be carried out, for example, by using the NIST photon number resolving detectors. We show that super-resolution and ``sub-Heisenberg'' sensitivity is obtained with TMSV and parity detection. In particular, in our setup, the signal as a function of the phase evolves $\bar {n}$ times faster than in traditional schemes, and the uncertainty in the phase estimation is better than $1 \mathord{\left/ {\vphantom {1 {\bar {n}}}} \right. \kern-\nulldelimiterspace} {\bar {n}}$.