arXiv subjects

Siamak Khademi

Publications and source records attributed to Siamak Khademi.

5 recordsLinked to original sources

arXiv2015

Non-classicality indicators for entangled and squeezed number states

Many non-classicality indicators are used to measure quantum effects of different systems. Kenfack's and Sadeghi's non-classicality indicators are introduced in terms of the amount of Wigner function's negativities and interferences in phase space quantum mechanics, respectively. They are, effectively, applied for some real distribution functions. In this paper, we compared these non-classicality indicators for the entangled state of photonic number states in the Wigner, Husimi and Rivier representations. It is shown that for a two-level entangled state, Sadeghi's indicator has more benefits with respect to the Kenfack's indicator. For the two-level entangled state, we show a correspondence between the Sadeghi's non-classicality indicator and the Von Neumann entropy. It is also shown that for the superposition of squeezed number state the Sadeghi's (and no Kenfack's) non-classicality indicators is sensible with respect to the squeezing parameter for a superposition of squeezed number states.

quant-ph↗

arXiv2012

A Sub Pixel Resolution Method

One of the main limitations for the resolution of optical instruments is the size of the sensor's pixels. In this paper we introduce a new sub pixel resolution algorithm to enhance the resolution of images. This method is based on the analysis of multi-images which are fast recorded during the fine relative motion of image and pixel arrays of CCDs. It is shown that by applying this method for a sample noise free image one will enhance the resolution with order of error.

physics.ins-det↗

arXiv2006

Non-Singular Magnetic Monopole

Magnetic Monopole is a cosequence of the existence of the duality symmetry in electromagnetics. Although, no conclusive experimental evidence have so far been found but the subject is still of much interest to physicist. The theory of magnetic monopoles was first proposed by Dirac in 1931 and soon after it was studied by physicist of many deciplines specially particle physics, quantum field theory and non-linear Soliton equations. One important consequence of the magnetic monopole theory is the quantization of the electric charge which was first derived by Dirac. In the definition of the classicaql magnetic monopole, the concept of Dirac string is used. dirac string is the locus of the points where the vector potential is nopt well-behave. On the other hand by introducing the idea of magnetic monopoles, Maxwell's equations became symmetrical with respect to the magnetic and electric fields, but they still remain unsymmetrical as far as the scalar and the vector potentials are concerned. In this work the electric and magnetic fields are redifined in termes of some new scalar and vector potentials, respectively, as a result of which the Maxwell's equations become symmetrical with respect to the potentials, too. One advantage of using this formulation is that one can discard the Dirac string all together. Finally, definition of the new potentials guarantees the lorentz invariance of equations.

physics.class-ph↗

arXiv2006

On derivation of Wigner distribution function

Wigner distribution function has much importance in quantum statistical mechanics. It finds applications in various disciplines of physics including condense matter, quantum optics, to name but a few. Wigner distribution function is introduced by E. Wigner in 1932. However, there is no analytical derivation of Wigner distribution function in the literatures, to date. In this paper, a simple analytical derivation of Wigner distribution function is presented. Our derivation is based on two assumptions, these are A) by taking the integral of Wigner distribution function, with respect to configuration space, the momentum space distribution function is obtained B) WDF is real. Similarly, and in addition to Wigner distribution function, the distribution function of Sobouti-Nasiri, which is imaginary, is also derived.

quant-ph↗

arXiv2006

Operator Gauge Symmetry in QED

In this paper, operator gauge transformation, first introduced by Kobe, is applied to Maxwell's equations and continuity equation in QED. The gauge invariance is satisfied after quantization of electromagnetic fields. Inherent nonlinearity in Maxwell's equations is obtained as a direct result due to the nonlinearity of the operator gauge transformations. The operator gauge invariant Maxwell's equations and corresponding charge conservation are obtained by defining the generalized derivatives of the first and second kinds. Conservation laws for the real and virtual charges are obtained too. The additional terms in the field strength tensor are interpreted as electric and magnetic polarization of the vacuum.

quant-ph↗