The Racah Institute of Physics
The Hebrew University of Jerusalem
Jerusalem 9190401
Israel
Office: 127 Popick
Phone: +972-2-6584998
Fax: +972-2-6584461
I am interested in physics of motion out of thermal equilibrium, quantitative description of social influence using financial market data, evolution of information assessment and light matter interaction. In the past enjoyed an opportunity to do nano-fabrication of photonic crystals and myocyte based robotics.
Here are some results:
Observations of animal contests pose a question whether the decision to quit the fight depends on the own state of the player (self-assessment) or on a state of the opponent (mutual assessment). We argue that conflict escalation, e.g. the snowdrift game or war of attrition, makes possible only the evolution of self-assessment. No constraint for the evolution of mutual assessment was found for social Prisoner's Dilemma. The theoretical predictions of this work are verified using statistical data of mating combats between specimens of male bowl and doily spiders. In collaboration with A. Engel.
Out of thermal equilibrium, an environment imposes effective mechanical forces on nanofabricated devices as well as on microscopic chemical or biological systems. Here we address the question of how to calculate these forces together with the response of the system from first principles. We show that an ideal gaslike environment, even near thermal equilibrium, can enforce a specific steady state on the system by creating effective potentials in otherwise homogeneous space. An example of stable and unstable rectifications of thermal fluctuations is presented using a modified Feynman-Smoluchowski ratchet with two degrees of freedom. Moreover, the stability of a steady configuration depends on its chiral symmetry.
Momentum transfer between matter and electromagnetic field is analyzed. The related equations of motion and conservation laws are derived using relativistic formalism. Their correspondence to various, at first sight self-contradicting, experimental data (the so-called Abraham-Minkowski controversy) is demonstrated. A new, Casimir-like, quantum phenomenon is predicted: contribution of vacuum fluctuations to the motion of dielectric liquids in crossed electric and magnetic fields. Velocities of about 50ââânm/s can be expected due to the contribution of high frequency vacuum modes. The proposed phenomenon could be used in the future as an investigating tool for zero fluctuations. Other possible applications lie in fields of microfluidics or precise positioning of micro-objects, e.g., cold atoms or molecules.
Construction of three-dimensional photonic crystals for optical wavelengths presents many technological and material science challenges. The submicron-feature-size sculpturing must be performed in high-refractive-index materials. We present the fabrication and optical characterization of â¼750ânm feature-size simple cubic woodpile photonic crystals from As2S3 (nâ2.2). The process is based on interference lithography and the layer-by-layer construction. PhD advisor B. Sfez. In collaboration with V. Lyubin and M. Klebanov.
