  We study the phase super-sensitivity of a Mach-Zehnder interferometer (MZI)
with the squeezed Kerr and coherent states as the inputs. We discuss the lower
bound in phase sensitivity by considering the quantum Fisher information (QFI)
and corresponding quantum Cramer-Rao bound (QCRB). With the help of single
intensity detection (SID), intensity difference detection (IDD) and homodyne
detection (HD) schemes, we find that our scheme gives better sensitivity in
both the lossless as well as in lossy conditions as compared to the combination
of well-known results of inputs as coherent plus vacuum, coherent plus squeezed
vacuum and double coherent state as the inputs. Because of the possibility of
generation of squeezed Kerr state (SKS) with the present available quantum
optical techniques, we expect that SKS may be an alternative nonclassical
resource for the improvement in the phase super-sensitivity of the MZI under
realistic scenario.
