Azi Lipshtat

The Racah Institute of Physics
The Hebrew University of Jerusalem
Jerusalem 91904, Israel

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as I’m no longer in the Hebrew University.

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Telephone:	Office:	(972-2) 658-6332
	Home:	(972-2) 999-6173
Fax:		(972-2) 652-0089
Email:		azilip@cc.huji.ac.il

Brief Biography | Research Interests | Publications | My Family

Teaching (2004/2005)

First semester:
I was a teaching assistant In course 77305 "Waves and Optics".
Click here for the course page.

Second semester:
Now I'm a teaching assistant In course 77102 "Electricity and Magnetism".
In this course we use the HighLearn system.

Presentations

This poster was presented in The conference on Computational Physics (CCP2004) Genoa, Italy, 01-04 September 2004.

This movie was presented in The GNSP (March meeting) in Montreal , March 2004. It presents the coarsening of a fractal cluster.

More presentations will be available here soon.

Research Interests

Coarsening dynamics:
The dynamics of phase transition are considered to be ``scale invariant''. However, if the initial condition is a fractal cluster of one phase in the "sea" of the other phase, the scale invariance is broken. We have performed a comprehensive investigation of these dynamics, using numerical simulations of the Cahn-Hilliard equation. The simulation results closely resemble experimental results of Sharon et al. on the coarsening of fractal viscous fingering patterns in a radial Hele-Shaw cell.
Relevant publications: 1, 5, 7.
Modeling of surface chemistry:
Chemical reactions on dust grains are of crucial importance in interstellar chemistry because they produce molecular hydrogen and various organic molecules. Due to the submicron size of the grains and the low flux, the surface populations of reactive species are small and strongly fluctuate. Under these conditions rate equations fail and the master equation is needed for modeling these reactions. We have established the method of master equation for interstellar surface reactions and identified the range of parameters in which this method is needed. In complex reaction networks, the number of equations in the master equation grows exponentially with the number of reactive species, severely limiting its feasibility. For these cases we have developed the multiplane method which dramatically reduces the number of equations, thus enabling the incorporation of the master equation in models of interstellar chemistry.
Relevant publications: 2, 3, 4, 6, 9, 10, 11.
Modeling of genetic networks:
Recent advances in molecular biology techniques have made possible the measurement of populations of proteins and mRNA's in simple genetic networks. Measurements of the average protein content of cells and their time dependence enabled to quantify the behavior of genetic networks. These measurements have been modeled using rate equations, mainly under quasi steady state conditions. However, real biological systems are likely be away from steady state. Furthermore, many components of cells appear in low copy numbers and are therefore subjected to large fluctuations. The modeling of these fluctuations requires the master equation formalism. We consider the modeling of simple genetic regulation networks using the master equation approach, and investigate the significance of noise and fluctuations in the dynamics of cell populations.
Relevant publication: 8, 11, 12.