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 more

CO2 molecule

The Hartree-Fock program

Introduction After some posts about the theory it is time to present the Hartree-Fock program1. You might find the previous posts useful, along with the links in there: How to solve a quantum many-body problem, The Hartree-Fock method. Here is the program in action (the final version might have minor differences): Although it doesn’t show … Read more

Event Driven Molecular Dynamics

Event Driven Molecular Dynamics

Introduction I intended to have some molecular dynamics code for this blog, something a little bit more complex than the one described at Newtonian Gravity post, perhaps something with neighbors lists or maybe again something about gravity but with a Barnes–Hut simulation. I’ll do that maybe later. I found that there are plenty of places … Read more

Magnetization for 2D Ising Model

Metropolis for 2D Ising and spin block renormalization

Introduction After quite a bit of time, here is the C++ program I promised. I’ve made a youtube video just to present it, for more meaningful results it must run with way more sweeps than in the video: It turned out that the program I used for making the video had some troubles with the … Read more