Eylem Seç
Perturbation Theories Based on the Density Matrix Renormalization Group
Başlık:
Perturbation Theories Based on the Density Matrix Renormalization Group
Yazar:
Guo, Sheng, author.
ISBN:
9780438048799
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (100 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: Garnet K. Chan Committee members: Roberto Car; John T. Groves; Annabella Selloni.
Özet:
This thesis describes the development of perturbation theories based on the density matrix renormalization group (DMRG) and their applications to strongly correlated electronic systems. We introduce two types of perturbation theories based on DMRG for systems with a mixture of static and dynamic correlation.
The first one uses the framework of multi-reference perturbation theory. We present a combination of the DMRG and the strongly-contracted variant of second order N-electron valence state perturbation theory (SC-NEVPT2) that uses an efficient algorithm to compute high order reduced density matrices from DMRG wave functions. To demonstrate its capability, we apply it to calculations of the chromium dimer potential energy curve at the basis set limit, and the excitation energies of the poly-p-phenylene vinylene trimer.
The second one, perturbative DMRG (p-DMRG), is designed for systems with very large active spaces. In p-DMRG, a zeroth-order wavefunction with a small number of variational parameters is first obtained by a standard DMRG calculation. Then, the residual correlation is recovered by a second-order perturbative treatment. To circumvent the problem of a large bond dimension in the first order wavefunction, we use a sum of several DMRG wavefunctions and extrapolation schemes to expand the first-order wavefunction, yielding substantial savings in computational cost and memory.
We also present an efficient stochastic algorithm for p-DMRG, which bypasses the difficulty in solving the first-order equation in the deterministic algorithm. The key part of the algorithm is to represent the right hand side of the first-order equation, QVˆ
Notlar:
School code: 0181
Tüzel Kişi Ek Girişi:
Mevcut:*
Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(681860.1) | 681860-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
On Order
Liste seç
Bunu varsayılan liste yap.
Öğeler başarıyla eklendi
Öğeler eklenirken hata oldu. Lütfen tekrar deneyiniz.
:
Select An Item
Data usage warning: You will receive one text message for each title you selected.
Standard text messaging rates apply.