214,622 research outputs found

    Calculating adiabatic evolution of the perturbed DNLS/MNLS solitons

    Full text link
    A symbolic computation technique is developed to calculate adiabatic evolution equations for parameters of the perturbed DNLS/MNLS solitons obtained by the recently developed direct perturbation theory [X.-J. Chen and J. Yang, Phys. Rev. E {\bf 65}, 066608(2002)]. Effects of the intrapulse Raman scattering, third-order group velocity dispersion, and narrow-banded filters with nonlinear gain on the MNLS solitons are studied as examples.Comment: 10 pages, 1 figure. to be published on Phys. Lett.

    Comment on "Quantum discord through the generalized entropy in bipartite quantum states"

    Full text link
    In [X.-W. Hou, Z.-P. Huang, S. Chen, Eur. Phys. J. D 68, 1 (2014)], Hou et al. present, using Tsallis' entropy, possible generalizations of the quantum discord measure, finding original results. As for the mutual informations and discord, we show here that these two types of quantifiers can take negative values. In the two qubits instance we further determine in which regions they are non-negative. Additionally, we study alternative generalizations on the basis of R\'enyi entropies.Comment: 5 pages, 4 figure