Quantum phase estimation with four-headed cat states

Su-Yong Lee, Chang-Woo Lee, Hyunchul Nha, Dagomir Kaszlikowski

Published 2014-09-15Version 1

We study a four-headed cat state (4HCS), namely, a superposition of four different coherent states, and propose its application to quantum phase estimation. We first investigate how the 4HCS is more nonclassical than a typical two-headed cat state (2HCS) in view of some nonclassical measures including the sub-Poissonian statistics, negativity of Wigner distribution, and entanglement potential. We then demonstrate the enhanced performance in phase estimation by employing an entangled state via the 4HCS, which can surpass that of the 2HCS particularly in the regime of small average photon number. We also show that an entangled state modified from the 4HCS can further enhance the phase estimation even in the regime of large average photon number with photon loss.