# Bijan Chokoufe Nejad - Physics

## Bijan Chokoufe Nejad

### 2014-04-25

## talks

All presentations have been created with the Beamer LaTeX class.

### Checkpointing in CUBA

Status report of the six-week *FOKUS research internship* at the Max Planck Institute Munich with Dr. Thomas Hahn. Main topic is the implementation of check-pointing, i.e. saving of current progress, for the CUBA library which offers different methods for multidimensional numerical integration. (2013, English)

### Geometric Origin of Scaling in Large Traffic Networks

A discussion of the paper by Popović et al. which shows that the observed scaling exponents have a geometric origin. A simple model is studied both analytically and in simulations with agreeing results for the exponents. Originally prepared for the *FOKUS research module: Complex Systems* of Prof. H. Hinrichsen, Prof. W. Kinzel and Dr. J. Reichardt. (2013, English)

### Symmetry of the Superconducting Gap

The first part is a quick reminder of the theory of superconductivity as mean-field solution. In the second part, the gap function is decomposed in basis functions with the symmetry of the lattice. Originally prepared for the *Oberseminar: Symmetries in solid state physics* with Prof. G. Sangiovanni. (2012, German)

### Introduction to Quantum Computing

A rather basic introduction to quantum computing, originally prepared for the lecture *Information Theory and Quantum Computing* of Prof. H. Hinrichsen and Dr. J. Reichardt. (2012, English)

### Ferromagnetism

A talk about spin waves, also known as magnons, in the Heisenberg model, originally prepared for the lecture *Quantum Mechanics III: Many-Body Physics* of Prof. W. Hanke. (2012, German)

### Nonlinear Oscillations

This presentation about nonlinear behaviour, especially in the Duffing oscillator, contains a video of a rather neat simulation where you can see chaotic behaviour. It has been created with Mathematica. The talk also comes with proceedings for the interested reader. Originally prepared for the *Hauptseminar* of PD W. Winter. (2011, German)

## write-ups

### Numerical Calculations of Multi-Jet Cross Sections

My *Master thesis* at TP II: Theoretical Elementary Particle Physics (University of Wuerzburg), supervised by Prof. Dr. T. Ohl, includes a new computational method to compute amplitudes with a virtual machine. Furthermore, methods for the efficient computation of multi-jet cross sections are reviewed, especially helicity Monte Carlo and QCD antenna phase space sampling. The corresponding talk is pending. (2014, English)

### Decays of the Higgs boson

A *Miniresearch Project* about the various decays of the Higgs boson in the Standard model. Covered are all tree level processes as well as the one-loop calculation of the decay to two gluons. Finally, the branching ratios are shown and compared to the literature. (2012, English)

### Landau levels in bilayer quantum spin Hall systems

My *Bachelor thesis* at TP IV: Mesoscopic Physics (University of Wuerzburg), supervised by Prof. Dr. B. Trauzettel and Dr. P. Michetti, provides a theoretical calculation of the expected experimental results when a strong magnetic field is applied to a double quantum well with interlayer voltage. It is shown that the existence of a crossing of *n* = 0 Landau levels leads to the same necessary condition for the interlayer voltage as the existing calculation of the topological invariant. For this work, there is also a talk available. (2012, English)