What a Born effective charge actually measures
It is not the charge on an ion. It is how much the polarisation of a crystal changes when you nudge that ion, and it is the quantity behind LO–TO splitting.
Notes
Notes
Short pieces on chaos theory, materials modelling and the tools in between.
How fast the butterfly forgets
Chaos has a speed. For the Lorenz system it is about 0.906 per unit time, and it sets how far ahead any forecast can see. Measuring it takes thirty lines of code.
Why the Lorenz attractor looks like a butterfly
Three equations, two unstable fixed points and a trajectory that never repeats. What is going on in the animation on the home page.