A successful phonon calculation within the quantum Monte Carlo framework

The focus and ultimate goal of computational research in materials science and condensed matter physics is to solve the Schrödinger equation—the fundamental equation describing how electrons behave inside matter—exactly (without resorting to simplifying approximations). While experiments can certainly provide interesting insights into a material’s properties, it is often computations that reveal the underlying physical mechanism. However, computations need not rely on experimental data and can, in fact, be performed independently, an approach known as “ab initio calculations.” The density functional theory (DFT) is a popular example of such an approach.