Phase sensitivity of a quantum Mach-Zehnder interferometer for a coherent state input

摘要

The phase sensitivity of a Mach-Zehnder interferometer utilizing quantum entanglement is analyzed for a coherent state input. The results show that the Heisenberg limit in the measurement of the phase shift is obtainable with a coherent input. Moreover, the scheme turns out to be immune to the imperfect detector efficiencies. This suggests another promising route for implementing sub-shot-noise measurement schemes.