9,907 research outputs found
Effects of the third-order dispersion on continuous waves in complex potentials
A class of constant-amplitude (CA) solutions of the nonlinear Schrodinger
equation with the third-order spatial dispersion (TOD) and complex potentials
are considered. The system can be implemented in specially designed planar
nonlinear optical waveguides carrying a distribution of local gain and loss
elements, in a combination with a photonic-crystal structure. The complex
potential is built as a solution of the inverse problem, which predicts the
potential supporting a required phase-gradient structure of the CA state. It is
shown that the diffraction of truncated CA states with a correct phase
structure can be strongly suppressed. The main subject of the analysis is the
modulational instability (MI) of the CA states. The results show that the TOD
term tends to attenuate the MI. In particular, simulations demonstrate a
phenomenon of weak stability, which occurs when the linear-stability analysis
predicts small values of the MI growth rate. The stability of the zero state,
which is a nontrivial issue in the framework of the present model, is studied
tooComment: 8 pages, 8 figures, Eur. Phys. J. D, in pres
Insulator-to-metal phase transition in Yb-based Kondo insulators
The periodic Anderson lattice model for the crystalline electric field
(CEF)split 4f quartet states is used to describe the Yb-based Kondo
insulators/semiconductors. In the slave-boson mean-field approximation, we
derive the hybridized quasiparticle bands, and find that decreasing the
hybridization difference of the two CEF quartets may induce an
insulator-to-metal phase transition. The resulting metallic phase has a hole
and an electron Fermi pockets. Such a phase transition may be realized
experimentally by applying pressure, reducing the difference in hybridization
of the two CEF quartets.Comment: 5 pages, 3 figure
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