CheMPS2 : Improved DMRG-SCF routine and correlation functions

Wouters, Sebastian; Poelmans, Ward; Baerdemacker, Stijn De; Ayers, Paul W.; Neck, Dimitri Van

doi:10.1016/j.cpc.2015.01.007

Cited by 18 publications

(22 citation statements)

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“…[24,48,49,82,126] In the treatment of problems where large active spaces are mandatory to obtain reliable and accurate results, it has proven capable of going well beyond the limits of present day quantum chemistry methods and even reach the full-CI limit. [38,42,43,[101][102][103][104][105][106][107][108]127] In the past decade, the method has gone through major algorithmic developments by various groups. [20,74,101,102,107,109] For example, the two-body reduced density matrices calculated with the DMRG method [24,49,66] can be used in the standard orbital optimization procedure.…”

Section: Tensor Product Methods In Quantum Chemistrymentioning

confidence: 99%

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Tensor product methods and entanglement optimization for ab initio quantum chemistry

Szalay

Pfeffer

Murg

et al. 2015

Int J of Quantum Chemistry

280

395

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The treatment of high-dimensional problems such as the Schr€ odinger equation can be approached by concepts of tensor product approximation. We present general techniques that can be used for the treatment of high-dimensional optimization tasks and time-dependent equations, and connect them to concepts already used in many-body quantum physics. Based on achievements from the past decade, entanglement-based methods-developed from different perspectives for different purposes in distinct communities already matured to provide a variety of tools-can be combined to attack highly challenging problems in quantum chemistry. The aim of the present paper is to give a pedagogical introduction to the theoretical background of this novel field and demonstrate the underlying benefits through numerical applications on a text book example. Among the various optimization tasks, we will discuss only those which are connected to a controlled manipulation of the entanglement which is in fact the key ingredient of the methods considered in the paper. The selected topics will be covered according to a series of lectures given on the topic "New wavefunction methods and entanglement optimizations in quantum

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Section: Tensor Product Methods In Quantum Chemistrymentioning

confidence: 99%

“…[258] Other free source codes with SU(2) spin symmetries are also available. [127,259] Utilization of symmetries allows one to target states with given symmetries and to keep M number of multiplets what corresponds to significantly more U(1) states what is crucial in order to achieve good numerical accuracy.…”

Section: 44mentioning

confidence: 99%

Tensor product methods and entanglement optimization for ab initio quantum chemistry

Szalay

Pfeffer

Murg

et al. 2015

Int J of Quantum Chemistry

280

395

View full text Add to dashboard Cite

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“…The methods compared are CCSD(T) in the MO basis and the CISDDT (Mmin CISD , CAS (10,18)). Density matrix renormalisation group (DMRG) 14,15 energies with FCI accuracy are added as a reference. CCSD(T) performs better at equilibrium and intermediate bond distances, but the approximate hybrid method outperforms CCSD(T) in the dissociation limit.…”

Section: Approximate Hybrid Docimentioning

confidence: 99%

“…13 For the interface with PSI4, we used the Hamiltonian class of CheMPS2. 14,15 For all DOCI, truncated DOCI, and hybrid DOCI calculations, a general CI solver is used that takes as argument a list of Slater determinants. These Slater determinants, in turn, are built from an orthonormal set of orbitals that may correspond to molecular orbitals or some other orthonormal set.…”

Section: A Computational Details and CI Solvermentioning

confidence: 99%

Polynomial scaling approximations and dynamic correlation corrections to doubly occupied configuration interaction wave functions

Raemdonck

Alcoba

Poelmans

et al. 2015

The Journal of Chemical Physics

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A class of polynomial scaling methods that approximate Doubly Occupied Configuration Interaction (DOCI) wave functions and improve the description of dynamic correlation is introduced. The accuracy of the resulting wave functions is analysed by comparing energies and studying the overlap between the newly developed methods and full configuration interaction wave functions, showing that a low energy does not necessarily entail a good approximation of the exact wave function. Due to the dependence of DOCI wave functions on the single-particle basis chosen, several orbital optimisation algorithms are introduced. An energy-based algorithm using the simulated annealing method is used as a benchmark. As a computationally more affordable alternative, a seniority number minimising algorithm is developed and compared to the energy based one revealing that the seniority minimising orbital set performs well. Given a well-chosen orbital basis, it is shown that the newly developed DOCI based wave functions are especially suitable for the computationally efficient description of static correlation and to lesser extent dynamic correlation. C 2015 AIP Publishing LLC. [http://dx

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“…This ansatz was first exploited for DMRG-SCF in the [augmented Hessian (AH)] Newton-Raphson-like (NR) implementation by Ghosh and co-workers 26 and Wouters et al 36,37 . Its implementation was also described by Ma and Ma 38 who, in addition, presented a pilot DMRG-SCF implementation of the Werner-Meyer (WM) MCSCF algorithm 39 .…”

Section: Introductionmentioning

confidence: 99%

Second-Order Self-Consistent-Field Density-Matrix Renormalization Group

Knecht

Keller

et al. 2017

J. Chem. Theory Comput.

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We present a matrix-product state (MPS)-based quadratically convergent densitymatrix renormalization group self-consistent-field (DMRG-SCF) approach. Following a proposal by Werner and Knowles (J. Chem. Phys. 82, 5053, (1985)), our DMRG-SCF algorithm is based on a direct minimization of an energy expression which is correct to second-order with respect to changes in the molecular orbital basis. We exploit a simultaneous optimization of the MPS wave function and molecular orbitals in order to achieve quadratic convergence. In contrast to previously reported (augmented Hessian) Newton-Raphson and super-configuration-interaction algorithms for DMRG-SCF, energy convergence beyond a quadratic scaling is possible in our ansatz.Discarding the set of redundant active-active orbital rotations, the DMRG-SCF energy converges typically within two to four cycles of the self-consistent procedure.

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CheMPS2 : Improved DMRG-SCF routine and correlation functions

Cited by 18 publications

References 0 publications

Tensor product methods and entanglement optimization for ab initio quantum chemistry

Tensor product methods and entanglement optimization for ab initio quantum chemistry

Polynomial scaling approximations and dynamic correlation corrections to doubly occupied configuration interaction wave functions

Second-Order Self-Consistent-Field Density-Matrix Renormalization Group

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