Here is a webpage for the exact diagonalization (ED) tutorial lecture in "APCTP-IACS-SNBNCBS WORKSHOP ON COMPUTATIONAL METHODS FOR EMERGENT QUANTUM MATTER: FROM THEORETICAL CONCEPTS TO EXPERIMENTAL REALIZATION".
The goal of this tutorial is to understand the principles of the three Lanczos-based methods, Lanczos, Finite-Temperature Lanczos, and continued fraction methods. These methods are important and fundamental to investigate the ground-state, finite-temperature physics, and spin dynamics from finite-size clusters of quantum frustrated magnets. We here focus on an S=1/2 XXZ spin model for simplicity. We will also learn how to make S=1/2 ED codes with bit representations and bitwise operations, which are efficient for fast ED codes, and will learn the simplest block diagonalization technique under conserved magnetization via Python ED sample codes.
Our python ED codes are based on TITPACK ver 2. We used Dr. Ryui Kaneko's Python ED codes as references. We also appreciate Dr. Katsuhiro Morita for checking the reliability of our Finite-Temperature Lanczos code.