Hubbard Model Illustration (IMAGE) Simons Foundation Caption An illustration of colored balls on a chessboard-like grid similar to the Hubbard model. Credit Lucy Reading-Ikkanda/Simons Foundation Usage Restrictions None License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.