WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653
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Article Diffraction in Time of Matter Waves Located in a Confined Region(Springer Heidelberg, 2022) Umul, Yusuf Z.The process of diffraction in time of a standing matter wave is studied. This case occurs generally when a quantum particle is confined in a trap or infinite potential well. First of all, the wave-function of a classical time diffracted matter wave is studied by considering a separation of the Fresnel function in terms of geometrical optics and diffracted waves. The behavior of the matter wave which is the counterpart of a geometrical optics field is investigated. Then a confined particle in a one-dimensional infinite potential well is taken into account. One of the walls of the trap is remained at an initial time and the process of diffraction in time is formulated by using the information, obtained from the geometrical optics fields. Some numerical results are given. This paper proposes two original approaches. The first one is the application of the optical diffraction theory to quantum physics. This is the separation of the scattered field into geometric optics and diffracted wave components. The second novelty is the addition of the effects of both of the traveling waves, which compose the standing wave, to the scattering integral.Article Citation - WoS: 3Citation - Scopus: 3Diffraction of Electromagnetic Waves by an Anomalously Transmitting Metasurface Half-Plane in Anisotropic Plasma(Elsevier Gmbh, 2020) Umul, Yusuf Z.The paper deals with the scattering of magnetic polarized electromagnetic plane waves by a anomalously transmitting metasurface half-plane, located in anisotropic plasma. Such a medium occurs for cold magnetized plasma, in which a static magnetic field exists. In this case the permittivity of the medium is expressed as a tensor, the elements of which are functions of the magnetostatic field, electron's mass and charge and angular frequency of the plasma. The metasurface half-plane transmits part of the incoming electromagnetic wave with a different angle from the angle of incidence, absorbing the remaining part. First of all, we will obtain the scattered geometric optics wave by subtracting the incident field from the total geometric optics wave. Then the kernel of a physical optics type scattering integral will be constructed with the aid of the integral theory of diffraction. The uniform diffracted magnetic field will be obtained from the physical optics integral. The total magnetic field will be evaluated as a sum of the total geometric optics and diffracted waves. The behaviours of the derived fields will be analyzed numerically.Article Comparison of Diffraction Methods for Lunar Occultations(Elsevier Gmbh, 2020) Umul, Yusuf Z.The only analytical method, which is used for the mathematical analysis of lunar occultations, is the Fresnel diffraction. The Fresnel integral is derived from the diffraction integral of Kirchhoff under some approximations. This paper aims to compare this method with the exact solution of Sommerfeld, which is obtained for a perfect electric conductor half-plane. The geometrical optics and diffracted fields are expressed separately. Numerical simulations are given for the comparison of two different total and diffracted waves.Editorial Citation - WoS: 1Citation - Scopus: 1Reply To the "a Comment on "the Photon Momentum(Elsevier Gmbh, Urban & Fischer verlag, 2014) Umul, Yusuf Z.Editorial Citation - WoS: 5Citation - Scopus: 5Comments on "on the Modified Theory of Physical Optics(Ieee-inst Electrical Electronics Engineers inc, 2014) Umul, Yusuf Z.Correction Comment on "a Survey of the New Proposal About the Photon Momentum" (Vol 148, Pg 342, 2017)(Elsevier Gmbh, Urban & Fischer verlag, 2018) Umul, Yusuf Z.Article Citation - WoS: 2Citation - Scopus: 2Scattering of a Bessel Beam by a Resistive Disc(Elsevier Gmbh, Urban & Fischer verlag, 2017) Umul, Yusuf Z.Bessel beam has two important advantages that make it preferable for the illumination process of biological samples in microscopy. These are the properties of non-diffraction and self-healing. In this paper, the interaction of the zeroth order Bessel beam with a resistive disc, which models a cell or tissue, is investigated by using the uniform geometrical theory of diffraction. The geometrical optics and diffracted waves are evaluated. The scattering characteristics of the beam and the property of self-healing are studied numerically for different values of the surface resistivity. (C) 2016 Elsevier GmbH. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 1The Relation Between Wave Vector and Momentum in Quantum Mechanics(Elsevier Gmbh, 2016) Umul, Yusuf Z.The fundamental relation of quantum mechanics, which correlates the momentum of a quantum particle to the wave vector of the matter wave, is re-interpreted. The wave vector, in the relation, is formulized as the integration of it along the angular coordinates for two and three dimensional cases. Various evaluations of the wave vector are performed for different types of waves and the results are discussed. Also the edge diffracted fields are considered according to the new interpretation. (C) 2016 Elsevier GmbH. All rights reserved.Article Citation - WoS: 3Citation - Scopus: 4The Physical Optics Integral on the Scatterer's Unlit Surface(Elsevier Gmbh, 2014) Umul, Yusuf Z.The scattering integrals of the modified theory of physical optics are redefined according to the illuminated and unlit surfaces of the scattering object. With this aim the canonical problem of wedge diffraction is taken into account. It is shown that the new scattering integral contain two geometrical optics and diffracted fields. One of the geometrical optics waves is the reflected field component that propagates in the real space. The other one transmits to an imaginary space through the scattering surface and does not have any influence in the real space. The diffracted waves exist in the real space and satisfy the related boundary condition on the scattering surfaces. The resultant field expressions are compared with the exact series solution of the problem numerically. (C) 2014 Elsevier GmbH. All rights reserved.Article Citation - WoS: 2Citation - Scopus: 2Diffraction of Plane Waves by the Interface Between Black and Soft/Hard Semi-Planes(Elsevier Gmbh, 2012) Umul, Yusuf Z.A theory of scattering, based on the non-perturbation of the incident field, is developed for the black bodies. The method is applied to the diffraction problem of plane waves by an interface between the black and soft/hard half-planes. The solutions are obtained in terms of infinite series and then transformed into Fresnel integrals. The scattered fields are investigated numerically. (C) 2011 Elsevier GmbH. All rights reserved.