IPM Calendar 
Wednesday 4 October 2023   Today  
Events for day: Wednesday 27 September 2023    
           11:00 - 12:00     Journal Club: Experiment & Phenomenology meeting
Simulation and experimental study of proton bunch self-modulation in plasma with linear density gradients



We present numerical simulations and experimental results of the self-modulation of a long proton bunch in a plasma with linear density gradients along the beam path. Simulation results agree with the experimental results reported: with negative gradients, the charge of the modulated bunch is lower than with positive gradients. In addition, the bunch modulation frequency varies with gradient. Simulation results show that dephasing of the wakefields with respect to the relativistic protons along the plasma is the main cause for the loss of charge. The study of the modulation frequency reveals details about the evolutio ...

           14:00 - 15:00     Combinatorics and Computing Weekly Seminar
Skew Types of Skew Hadamard Matrices


A Hadamard matrix $H$ is said to be skew Hadamard if $H+H^t=2I$, where I is the identity matrix. Skew Hadamard matrices are useful in constructing several combinatorial objects, such as association schemes, self-dual codes, and strongly regular graphs. The notions of type and profile have been proved to be very useful in classification and equivalence check of Hadamard matrices. Here, we define skew type for skew Hadamard matrices. We make use of it to classify some types of skew Hadamard matrices of order $36$. This is a joint work with Hadi Kharaghani and Ali Mohammadian.

https://us06web.zoom.us/j/83407340293?pwd=cXarB4geU ...

           16:00 - 17:00     Mathematics Colloquium
How to Construct Free Boundary Problems from Simple Optimization Problems


I will start by displaying a model of a free boundary problem which by now belongs to the folklore. Then, I will go over some well-known facts in regard to the Poisson problem with zero Dirichlet boundary conditions. Finally, I will introduce the optimization problems which will lead us to the aforementioned free boundary problems. Some open problems and intriguing questions will be shared as well.

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Venue: Niavaran, Lecture Hall 1 ...