title: Nonexistence of entanglement sudden death in dephasing of high NOON states.
abstract: We study the dynamics of entanglement in continuous variable quantum systems. Specifically, we study the phenomena of entanglement sudden death (ESD) in general two-mode-N-photon states undergoing pure dephasing. We show that for these circumstances, ESD never occurs. These states are generalizations of the so-called high NOON states (i.e., a superposition of N photons in the first mode, O in the second, with O photons in the first, N in the second), shown to decrease the Rayleigh limit of lambda to lambda/N, which promises great improvement in resolution of interference patterns if states with large N are physically realized [Phys. Rev. Lett.85, 2733 (2000)]. However, we show that in dephasing NOON states, the time to reach some critical visibility Vcrit, scales inversely with N2. On the practical level, this shows that as N increases, the visibility degrades much faster, which is likely to be a considerable drawback for any practical application of these states.
authors.affiliation: Department of Physics, University of Toronto, Toronto, Ontario, Canada. alqasimi@physics.utoronto.ca
authors.forename: Asma
authors.initials: A
authors.lastname: Al-Qasimi
authors.forename: Daniel F V
authors.initials: DF
authors.lastname: James