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We present an efficient stochastic algorithm for the recently introduced perturbative density matrix renormalization group (p-DMRG) method for large active spaces. The stochastic implementation bypasses the computational bottleneck involved…

Chemical Physics · Physics 2018-08-01 Sheng Guo , Zhendong Li , Garnet Kin-Lic Chan

The performance of the density matrix renormalization group (DMRG) is strongly influenced by the choice of the local basis of the underlying physical lattice. We demonstrate that, for the two-dimensional Hubbard model, the hybrid…

Strongly Correlated Electrons · Physics 2017-03-22 G. Ehlers , S. R. White , R. M. Noack

Shared-memory parallelization (SMP) strategies for density matrix renormalization group (DMRG) algorithms enable the treatment of complex systems in solid state physics. We present two different approaches by which parallelization of the…

Strongly Correlated Electrons · Physics 2009-11-10 G. Hager , E. Jeckelmann , H. Fehske , G. Wellein

We describe a low cost alternative to the standard variational DMRG (density matrix renormalization group) algorithm that is analogous to the combination of selected configuration interaction plus perturbation theory (SCI+PT). We denote the…

Chemical Physics · Physics 2018-03-28 Sheng Guo , Zhendong Li , Garnet Kin-Lic Chan

The widely used density matrix renormalization group (DRMG) method often fails to converge in systems with multiple length scales, such as lattice discretizations of continuum models and dilute or weakly doped lattice models. The local…

Quantum Gases · Physics 2012-07-17 M. Dolfi , B. Bauer , M. Troyer , Z. Ristivojevic

We theoretically derive and validate with large scale simulations a remarkably accurate power law scaling of errors for the restricted active space density matrix renormalization group (DMRG-RAS) method [arXiv:2111.06665] in electronic…

Chemical Physics · Physics 2023-04-04 Gero Friesecke , Gergely Barcza , Örs Legeza

The Kato-Bloch perturbation formalism is used to present a density-matrix renormalization-group (DMRG) method for strongly anisotropic two-dimensional systems. This method is used to study Heisenberg chains weakly coupled by the transverse…

Strongly Correlated Electrons · Physics 2009-11-10 S. Moukouri

Electronic and/or vibronic coherence has been found by recent ultrafast spectroscopy experiments in many chemical, biological and material systems. This indicates that there are strong and complicated interactions between electronic states…

Strongly Correlated Electrons · Physics 2019-12-12 Xiaoyu Xie , Yuyang Liu , Yao Yao , Ulrich Schollwock , Chungen Liu , Haibo Ma

We introduce a Lagrangian formulation of the Density Matrix Renormalization Group (DMRG). We present Lagrangians which when minimised yield the optimal DMRG wavefunction in a variational sense, both within the general matrix product ansatz,…

Strongly Correlated Electrons · Physics 2008-04-11 Garnet Kin-Lic Chan

An efficient density matrix renormalization group (DMRG) algorithm is presented and applied to Y-junctions, systems with three arms of $n$ sites that meet at a central site. The accuracy is comparable to DMRG of chains. As in chains, new…

Strongly Correlated Electrons · Physics 2016-03-23 Manoranjan Kumar , Aslam Parvej , Simil Thomas , S. Ramasesha , Z. G. Soos

We discuss the development of an angular-momentum-conserving variant of the Density Matrix Renormalization Group (DMRG) method for use in large-scale shell-model calculations of atomic nuclei and report a first application of the method to…

Nuclear Theory · Physics 2009-02-09 B. Thakur , S. Pittel , N. Sandulescu

Density matrix downfolding (DMD) is a technique for regressing low-energy effective Hamiltonians from quantum many-body Hamiltonians. One limiting factor in the accuracy of classical implementations of DMD is the presence of…

The emerging field of polaritonic chemistry explores the behavior of molecules under strong coupling with cavity modes. Despite recent developments in ab initio polaritonic methods for simulating polaritonic chemistry under electronic…

Chemical Physics · Physics 2024-07-02 Mikuláš Matoušek , Nam Vu , Niranjan Govind , Jonathan J. Foley , Libor Veis

We employ the density matrix renormalization group (DMRG) and the wave function factorization method for the numerical solution of large scale nuclear structure problems. The DMRG exhibits an improved convergence for problems with realistic…

Nuclear Theory · Physics 2007-05-23 T. Papenbrock , D. J. Dean

There are three essential problems in computational relativistic chemistry: electrons moving at relativistic speeds, close lying states and dynamical correlation. Currently available quantum-chemical methods are capable of solving systems…

Chemical Physics · Physics 2020-05-08 Jan Brandejs , Jakub Višňák , Libor Veis , Maté Mihály , Örs Legeza , Jiří Pittner

The particle-hole version of the density-matrix renormalization-group method (PH-DMRG) is utilized to calculate the ground-state energy of an interacting two-dimensional quantum dot. We show that a modification of the method, termed…

Disordered Systems and Neural Networks · Physics 2008-03-26 Yuval Weiss , Richard Berkovits

The strongly-contracted variant of second order N -electron valence state perturbation theory (NEVPT2) is an efficient perturbative method to treat dynamic correlation without the problems of intruder states or level shifts, while the…

Chemical Physics · Physics 2016-04-14 Sheng Guo , Mark A. Watson , Weifeng Hu , Qiming Sun , Garnet Kin-Lic Chan

We review the variational principle in the density matrix renormalization group (DMRG) method, which maximizes an approximate partition function within a restricted degrees of freedom; at zero temperature, DMRG mini- mizes the ground state…

Statistical Mechanics · Physics 2009-10-28 T. Nishino , K. Okunishi

The ground-state and low-energy excitations of quantum Hall systems are studied by the density matrix renormalization group (DMRG) method. From the ground-state pair correlation functions and low-energy excitions, the ground-state phase…

Strongly Correlated Electrons · Physics 2009-06-08 Naokazu Shibata

We present two new analytic formulations of the Density Matrix Renormalization Group Method. In these formulations we combine the block renormalization group (BRG) procedure with Variational and Fokker-Planck methods. The BRG method is used…

Condensed Matter · Physics 2015-06-25 Miguel A. Martin-Delgado , German Sierra