Block2: a comprehensive open source framework to develop and apply state-of-the-art DMRG algorithms in electronic structure and beyond

Abstract

Block2 is an open source framework to implement and perform density matrix renormalization group and matrix product state algorithms. Out-of-the-box it supports the eigenstate, time-dependent, response, and finite-temperature algorithms. In addition, it carries special optimizations for ab initio electronic structure Hamiltonians and implements many quantum chemistry extensions to the density matrix renormalization group, such as dynamical correlation theories. The code is designed with an emphasis on flexibility, extensibility, and efficiency, and to support integration with external numerical packages. Here we explain the design principles and currently supported features and present numerical examples in a range of applications.

20 pages, 8 figures

References in corpus (28)

• Array Programming with NumPy
• The radical character of the acenes: A density matrix renormalization group study
• Orbital Optimization in the Density Matrix Renormalization Group, with applications to polyenes and β-carotene
• The Density Matrix Renormalization Group in Chemistry and Molecular Physics: Recent Developments and New Challenges
• Low-energy spectrum of iron-sulfur clusters directly from many-particle quantum mechanics
• Minimally Entangled Typical Thermal State Algorithms
• The density matrix renormalization group for ab initio quantum chemistry
• A spin-adapted Density Matrix Renormalization Group algorithm for quantum chemistry
• Multireference Correlation in Long Molecules with the Quadratic Scaling Density Matrix Renormalization Group
• Time-step targetting methods for real-time dynamics using DMRG
• Real-time simulations of nonequilibrium transport in the single-impurity Anderson model
• A Strictly Single-Site DMRG Algorithm with Subspace Expansion
• Entanglement Measures for Single- and Multi-Reference Correlation Effects
• Generic Construction of Efficient Matrix Product Operators
• Chebyshev matrix product state approach for spectral functions
• Automatic code generation enables nuclear gradient computations for fully internally contracted multireference theory
• A flexible multi-reference perturbation theory by minimizing the Hylleraas functional with matrix product states
• Real-Space Parallel Density Matrix Renormalization Group
• Time-step targeting time-dependent and dynamical density matrix renormalization group algorithms with ab initio Hamiltonians
• Targeted Excited State Algorithms
• A General Automatic Method for Optimal Construction of Matrix Product Operators Using Bipartite Graph Theory
• Optimizing Hartree-Fock orbitals by the density-matrix renormalization group
• Transcorrelated Density Matrix Renormalization Group
• Ultrafast ab-initio Quantum Chemistry Using Matrix Product States
• A comparison between the one- and two-step spin-orbit coupling approaches based on the ab initio Density Matrix Renormalization Group
• Conservation laws in coupled cluster dynamics at finite-temperature
• Finite temperature density matrix embedding theory
• On the possibility to use non-orthogonal orbitals for Density Matrix Renormalization Group calculations in Quantum Chemistry