Microscopic quantum description of second-order nonlinearities in two-dimensional hexagonal nanostructures beyond the Dirac cone approximation

Two-dimensional solitons with second-order nonlinearities.

We investigate the propagation of intense Gaussian beams in materials with quadratic nonlinearity. Excitation of (2 + 1) solitons is numerically predicted at finite phase mismatch and in the presence of linear walk-off between the fundamental and second-harmonic waves. The numerical results are interpreted in terms of the conserved quantities of the wave evolution, and the appropriate condition...

Dynamical polarizability of graphene beyond the Dirac cone approximation

T. Stauber,1,2 J. Schliemann,3 and N. M. R. Peres1 1Centro de Física e Departamento de Física, Universidade do Minho, P-4710-057 Braga, Portugal 2Depto. de Física de la Materia Condensada, Universidad Autǿnoma de Madrid, E-28049 Madrid, Spain 3Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany Received 7 October 2009; revised manuscript received 16 December...

synthesis of platinum nanostructures in two phase system

چکیده پلاتین، فلزی نجیب، پایدار و گران قیمت با خاصیت کاتالیزوری زیاد است که کاربرد های صنعتی فراوانی دارد. کمپلکس های پلاتین(ii) به عنوان دارو های ضد سرطان شناخته شدند و در شیمی درمانی بیماران سرطانی کاربرد دارند. خاصیت کاتالیزوری و عملکرد گزینشی پلاتین مستقیماً به اندازه و- شکل ماده ی پلاتینی بستگی دارد. بعضی از نانو ذرات فلزی در سطح مشترک مایع- مایع سنتز شده اند، اما نانو ساختار های پلاتین ب...

A High Order Approximation of the Two Dimensional Acoustic Wave Equation with Discontinuous Coefficients

This paper concerns with the modeling and construction of a fifth order method for two dimensional acoustic wave equation in heterogenous media. The method is based on a standard discretization of the problem on smooth regions and a nonstandard method for nonsmooth regions. The construction of the nonstandard method is based on the special treatment of the interface using suitable jump conditio...

Polarization of graphene in a strong magnetic field beyond the Dirac cone approximation