‎The object of the present paper is to study spacetimes admitting‎ ‎quasi-conformal curvature tensor‎. ‎At first we prove that a quasi-conformally flat spacetime is Einstein‎ ‎and hence it is of constant curvature and the energy momentum tensor of such a spacetime satisfying‎ ‎Einstein's field equation with cosmological constant is covariant constant‎. ‎Next‎, ‎we prove that if the perfect flui...

Recently, photonic crystals doped with liquid crystal (LC) material havegained much research interest. In this article new ternary one-dimensional photoniccrystal introduced and studied. The liquid crystal layer of 5CB and 5PCH is sandwichedby two dielectric layers. For the first time, we use four structures SiO2/UCF35/CaF2,SiO2/5CB/CaF2, NFK51/UCF35/NPSK53 and NFK51/5CB/NPSK53. The effect ofte...

$\bf{Abstract}$: A qubit lattice algorithm (QLA), which consists of a set interleaved unitary collision-streaming operators, is developed for electromagnetic wave propagation in tensor dielectric media. External potential operators are required to handle gradients the refractive indices, and these typically non-unitary. similar problem arises QLA Korteweg-de Vries equation, as operator that mod...

Wave propagation in hyperbolic metamaterials is described by the Maxwell equations with a frequency-dependent tensor of dielectric permittivity, whose eigenvalues are different signs. In this case problem becomes (Klein--Gordon equation) for certain range frequencies. The principal theoretical and numerical difficulty comes from fact that equation posed free space, without initial conditions pr...

Spatially homogeneous Bianchi type-II, VIII and IX anisotropic, as well as isotropic cosmological models can be obtained in a scalar tensor theory of gravitation proposed by Saez and Ballester (1986) when the source for energy momentum tensor is a bulk viscous fluid containing one-dimensional cosmic strings. All the models obtained and presented here are expanding, non-rotating and accelerating...

a method for deformation computation based on strain tensor elements, as an alternative to the usual way of application of gradient of displacement vector, is proposed. the method computes directly the strain tensor elements from the computed/observed changes in distances and angles between the stations of a geodetic network in two epochs of observations. displacement vector which is determined...