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Andrzej Nowojewski

Publications and source records attributed to Andrzej Nowojewski.

3 recordsLinked to original sources

An analytical treatment of in-plane magnetotransport in the Falicov-Sievert model

We derive an analytical expression which allows efficient computation of the effect of all the Fermi surface trajectories induced by a combination of Bragg scattering and magnetic breakdown on the in-plane components of the resistivity tensor. The particular network of coupled orbits which we consider was first formulated by Falicov and Sievert, who studied the problem numerically. Our approach, based upon a method used previously to derive an analytical solution for interlayer transport, allows us to show that the conductivity tensor can be written as a sum of a matrix representing the effect of total magnetic breakdown and one representing a combination of complex electronic trajectories, and we find a compact expression for the in-plane components of the resistivity tensor that can be evaluated straightforwardly.

cond-mat.str-el

An analytically solvable model of the effect of magnetic breakdown on angle-dependent magnetoresistance in a quasi-two-dimensional metal

We have developed an analytical model of angle-dependent magnetoresistance oscillations (AMROs) in a quasi-two-dimensional metal in which magnetic breakdown occurs. The model takes account of all the contributions from quasiparticles undergoing both magnetic breakdown and Bragg reflection at each junction and allows extremely efficient simulation of data which can be compared with recent experimental results on the organic metal kappa-ET2Cu(NCS)2. AMROs resulting from both closed and open orbits emerge naturally at low field, and the model enables the transition to breakdown-AMROs with increasing field to be described in detail.

cond-mat.str-el

Gamow's bicycle: The Appearance of Bodies at Relativistic Speeds and Apparent Superluminal Velocities

A human creates an image basing on the information delivered by photons that arrived at his retina simultaneously. Due to finite and constant velocity of light these photons left the moving body at different times, since not all points of the body are equidistant. In other words its image represents the body as it was in several different times i.e. it is distorted and does not correspond to its real appearance. The useful experimental arrangement is set and then used to derive the general expression that transforms two-dimensional stationary shapes to their apparent forms, which could be photographed once they are set in motion. It is then used to simulate the so-called Gamow's bicycle combined out of circles and straight lines. The simulation outlines two important aspects of bike's motion: apparent distance of two points and apparent velocity which are then discussed thoroughly. It is found that the approaching body is elongated and its apparent speed is greater than its real one (under certain conditions can exceed the speed of light), whereas the receding one is contracted (but not in a matter of Lorentz contraction) with the speed smaller than the real one. Both the apparent length and speed tends to a certain limit when time tends to plus or minus infinity. The change of both parameters takes place in the vicinity of the nearest approach to the observer and is more rapid when the velocity greater and the distance is smaller. When the moving vertical rod is seen at right angle, its total apparent length is Lorentz contracted, however its interior is still distorted. At the same conditions apparent velocity of a point equals its real one. Finally it is proven that not only the apparent geometrical shape changes as the body moves but also its color according to Doppler shift.

physics.pop-ph