https://blog.neumo.top/tags/equivariant/Recent content in Equivariant on NeumoHugoen-USFri, 19 Jun 2026 14:03:50 +0800https://blog.neumo.top/posts/equivariant/Fri, 19 Jun 2026 14:03:50 +0800https://blog.neumo.top/posts/equivariant/<h2 id="introduction">Introduction</h2> <p>Suppose we want to simulate the motion of atoms in a molecule or a material. In principle, the forces on the nuclei come from quantum mechanics. In practice, this is hard because the full electron-nuclear Schrodinger equation is far too expensive to solve at every molecular dynamics step.</p> <p>The usual starting point is the Born-Oppenheimer approximation. Since nuclei are much heavier and move much more slowly than electrons, we treat the nuclear positions as fixed while solving the electronic problem. Let</p>