Numerical and Theoretical Aspects of the DMRGTCC Method Exemplified by the Nitrogen Dimer
Abstract
In this article, we investigate the numerical and theoretical aspects of the coupledcluster method tailored by matrixproduct states. We investigate chemical properties of the used method, such as energy size extensivity and the equivalence of linked and unlinked formulation. The existing mathematical analysis is here elaborated in a quantum chemical framework. In particular, we highlight the use of a socalled CASext gap describing the basis splitting between the complete active space and the external part. Moreover, the behavior of the energy error as a function of the optimal basis splitting is discussed. We show numerical investigations on the robustness with respect to the bond dimensions of the single orbital entropy and the mutual information, which are quantities that are used to choose the complete active space. Furthermore, we extend the mathematical analysis with a numerical study on the complete active space dependence of the error.
 Publication:

arXiv eprints
 Pub Date:
 September 2018
 arXiv:
 arXiv:1809.07732
 Bibcode:
 2018arXiv180907732F
 Keywords:

 Physics  Chemical Physics;
 Condensed Matter  Strongly Correlated Electrons;
 Physics  Atomic Physics;
 Physics  Computational Physics;
 Quantum Physics
 EPrint:
 doi:10.1021/acs.jctc.8b00960