Diamond band structure

Tight Binding

Introduction There are many methods to calculate band structures of crystals. I implemented the Empirical Pseudopotential project, some of the code can be reused for other methods. One of the methods is simple and fast, the tight binding method, so I simply took the code from the last project, cut a part out and modified … Read moreTight Binding

d orbital

DFT for a Quantum Dot

Introduction This post is describing another project that is leading (hopefully) towards something a little more serious: DFT Quantum Dot1. It will be a very short description because it’s Sunday. As usual, here is the program in action: It displays the quantum dot ‘orbitals’ with VTK volume rendering. Do not assign much physical reality to … Read moreDFT for a Quantum Dot

Kohn-Sham equations

Density Functional Theory

Introduction As I already revealed in the last post, I intend to have several projects with Density Functional Theory on this blog. I already have a simple project on GitHub, about a ‘quantum dot’1 with volumetric visualization of orbitals with VTK. I thought that exposing some theory in a separate post would be nice for … Read moreDensity Functional Theory

iTEBD

Time Evolving Block Decimation

Introduction I already mentioned Matrix Product States in the Density Matrix Renormalization Group post. I thought it would be a nice topic to have on this blog, but since I already implemented DMRG, I’ll have something a little different related with the subject. With the information presented here (mostly in the links) you could go … Read moreTime Evolving Block Decimation

DMRG sweep

Density Matrix Renormalization Group

Introduction As promised in the Numerical Renormalization Group post, I implemented a Density Matrix Renormalization Group program. As I start writing this post, the program is already on GitHub1. It’s quite basic, currently it is implemented only for Heisenberg model chains, for both spin 1/2 and 1. It runs only for even number of sites … Read moreDensity Matrix Renormalization Group