Infinite projected entangled pair states algorithm improved: Fast full update and gauge fixing

© 2015 American Physical Society. ©2015 American Physical Society. The infinite projected entangled pair states (iPEPS) algorithm [J. Jordan, Phys. Rev. Lett. 101, 250602 (2008)PRLTAO0031-900710.1103/PhysRevLett.101.250602] has become a useful tool in the calculation of ground-state properties of two-dimensional quantum lattice systems in the thermodynamic limit. Despite its many successful implementations, the method has some limitations in its present formulation which hinder its application to some highly entangled systems. The purpose of this paper is to unravel some of these issues, in turn enhancing the stability and efficiency of iPEPS methods. For this, we first introduce the fast f…