M. R. H. Khajehpour

Laser-induced dendritic microstructures on the surface of Ag+-doped glass

Fractal dendritic silver microstructures are observed on the surface of the Ag+-doped glasses as a result of a photothermal interaction with a focused multiline cw high-power (Pmax=8u2009W)u2009Ag+ laser beam. It is found that evolution of the structures depends on the exposure time and also on the concentration of the silver ions in the sample. The fractal dimension of the generated dendritic microstructures increases with the exposure time. Instability of the contact line of the molten silver flow toward the periphery of the interaction area is discussed as a result of the temperature gradient, due to the Gaussian intensity distribution across the laser beam.

A test theory of the local structure of spacetime: a Finslerian approach

For rival theories within the framework of the test theory of Mansouri--Sexl a geometrical setting in terms of Finsler geometry has been found. It is shown that the time dilation and length contraction parameters measure the deviation from a Riemannian geometry.

Statistical Physics of Complex Fluids

The field of complex fluids is a rapidly developing, highly interdisciplinary field that brings together people from a plethora of backgrounds such as mechanical engineering, chemical engineering, materials science, applied mathematics, physics, chemistry and biology. In this melting pot of science, the traditional boundaries of various scientific disciplines have been set aside. It is this very property of the field that has guaranteed its richness and prosperity since the final decade of the 20th century and into the 21st. The C3 Commission of the International Union of Pure and Applied Physics (IUPAP), which is the commission for statistical physics that organizes the international STATPHYS conferences, encourages various, more focused, satellite meetings to complement the main event. For the STATPHYS22 conference in Bangalore (July 2004), Iran was recognized by the STATPHYS22 organizers as suitable to host such a satellite meeting and the Institute for Advanced Studies in Basic Sciences (IASBS) was chosen to be the site of this meeting. It was decided to organize a meeting in the field of complex fluids, which is a fairly developed field in Iran. This international meeting, and an accompanying summer school, were intended to boost international connections for both the research groups working in Iran, and several other groups working in the Middle East, South Asia and North Africa. The meeting, entitled `Statistical Physics of Complex Fluids was held at the Institute for Advanced Studies in Basic Sciences (IASBS) in Zanjan, Iran, from 27 June to 1 July 2004. The main topics discussed at the meeting included: biological statistical physics, wetting and microfluidics, transport in complex media, soft and granular matter, and rheology of complex fluids. At this meeting, 22 invited lectures by eminent scientists were attended by 107 participants from different countries. The poster session consisted of 45 presentations which, in addition to the main topics of the meeting, covered some of the various areas in statistical physics currently active in Iran. About half of the participants came from countries other than Iran, with a relatively broad geographic distribution. The meeting benefited greatly from the excellent administrative assistance of the conference secretary Ms Ashraf Moosavi and the IASBS staff. We are grateful to Professor Yousef Sobouti, the Director of IASBS, and Professor Reza Mansouri, the Head of the Physical Society of Iran, for their support. We also thank the organizers of STATPHYS22, Professor Rahul Pandit and his colleagues, for their suggestions and support. The conference was supported by donations from the Center for International Research and Collaboration (ISMO) and the Institute for Research and Planning in Higher Education (IRPHE) of the Iranian Ministry of Science, Research and Technology, the Islamic Development Bank, the Abdus Salam International Centre for Theoretical Physics (ICTP), the Tehran Cluster Office of the United Nations Educational, Scientific and Cultural Organization (UNESCO), the Research and Development Directorate of the National Iranian Oil Company, the Physical Society of Iran, the Iranian Meteorological Organization, and the Zanjan City Water and Waste Water Company. Finally, we would like to express our gratitude to Institute of Physics Publishing, and in particular to Professor Alexei Kornyshev and Dr Richard Palmer for suggesting publishing the proceedings of the meeting and carrying through the editorial processes with the utmost efficiency.

Conductivity of a two-dimensional curved microconstriction

Abstract The quantum conductance of a long two-dimensional curved microconstriction has been considered theoretically. It is shown that over-the-barrier-reflection of electrons at points in which the curvature of the surface is changed, results in fine structure of quantum steps of the conductance. The observation of this structure would be a demonstration of the influence of the curvature on the quantum properties of two-dimensional electrons.

A dynamical test of special relativity using the anomalous electron g-factor

Abstract Using the geometrical structure found for rival theories of space-time, a dynamical test for the special theory of relativity is introduced in terms of the anomalous electron g -factor. The corresponding experimental measurements verify the validity of special relativity almost an order of magnitude more accurate than the best kinematical tests.