scholarly journals Communication: Finite size correction in periodic coupled cluster theory calculations of solids

2016 ◽  
Vol 145 (14) ◽  
pp. 141102 ◽  
Author(s):  
Ke Liao ◽  
Andreas Grüneis
Keyword(s):  
Finite Size ◽  
Coupled Cluster ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Size Correction ◽  
Finite Size Correction

Excitonic Coupled-cluster Theory: Part I, General Formalism

2017 ◽  
Author(s):  
Yuhong Liu ◽  
Anthony Dutoi
Keyword(s):  
Electron Correlation ◽  
Degrees Of Freedom ◽  
Model Systems ◽  
Coupled Cluster ◽  
Effective Hamiltonian ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Companion Article ◽  
High Level ◽  
Fragment Interaction

<div> <div>A shortcoming of presently available fragment-based methods is that electron correlation (if included) is described at the level of individual electrons, resulting in many redundant evaluations of the electronic relaxations associated with any given fluctuation. A generalized variant of coupled-cluster (CC) theory is described, wherein the degrees of freedom are fluctuations of fragments between internally correlated states. The effects of intra-fragment correlation on the inter-fragment interaction is pre-computed and permanently folded into the effective Hamiltonian. This article provides a high-level description of the CC variant, establishing some useful notation, and it demonstrates the advantage of the proposed paradigm numerically on model systems. A companion article shows that the electronic Hamiltonian of real systems may always be cast in the form demanded. This framework opens a promising path to build finely tunable systematically improvable methods to capture precise properties of systems interacting with a large number of other systems. </div> </div>

Excitonic Coupled-cluster Theory: Part I, General Formalism

2017 ◽  
Author(s):  
Yuhong Liu ◽  
Anthony Dutoi
Keyword(s):  
Electron Correlation ◽  
Degrees Of Freedom ◽  
Model Systems ◽  
Coupled Cluster ◽  
Effective Hamiltonian ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Companion Article ◽  
High Level ◽  
Fragment Interaction

<div> <div>A shortcoming of presently available fragment-based methods is that electron correlation (if included) is described at the level of individual electrons, resulting in many redundant evaluations of the electronic relaxations associated with any given fluctuation. A generalized variant of coupled-cluster (CC) theory is described, wherein the degrees of freedom are fluctuations of fragments between internally correlated states. The effects of intra-fragment correlation on the inter-fragment interaction is pre-computed and permanently folded into the effective Hamiltonian. This article provides a high-level description of the CC variant, establishing some useful notation, and it demonstrates the advantage of the proposed paradigm numerically on model systems. A companion article shows that the electronic Hamiltonian of real systems may always be cast in the form demanded. This framework opens a promising path to build finely tunable systematically improvable methods to capture precise properties of systems interacting with a large number of other systems. </div> </div>

scholarly journals Orbital optimized unitary coupled cluster theory for quantum computer

2020 ◽  
Vol 2 (3) ◽  
Author(s):  
Wataru Mizukami ◽  
Kosuke Mitarai ◽  
Yuya O. Nakagawa ◽  
Takahiro Yamamoto ◽  
Tennin Yan ◽  
...  
Keyword(s):  
Quantum Computer ◽  
Coupled Cluster ◽  
Coupled Cluster Theory ◽  
Cluster Theory

scholarly journals Focal-point approach with pair-specific cusp correction for coupled-cluster theory

2021 ◽  
Vol 154 (23) ◽  
pp. 234103
Author(s):  
Andreas Irmler ◽  
Alejandro Gallo ◽  
Andreas Grüneis
Keyword(s):  
Focal Point ◽  
Coupled Cluster ◽  
Coupled Cluster Theory ◽  
Cluster Theory

scholarly journals NUMERICAL STUDY OF CHARGE AND STATISTICS OF LAUGHLIN QUASIPARTICLES

1999 ◽  
Vol 14 (04) ◽  
pp. 537-557 ◽  
Author(s):  
HEIDI KJØNSBERG ◽  
JAN MYRHEIM
Keyword(s):  
Numerical Study ◽  
Finite Size ◽  
Expected Value ◽  
Wave Functions ◽  
Numerical Calculations ◽  
Filling Fraction ◽  
Slow Convergence ◽  
Berry Phases ◽  
Size Correction ◽  
Finite Size Correction

We present numerical calculations of the charge and statistics, as extracted from Berry phases, of the Laughlin quasiparticles, near filling fraction 1/3, and for system sizes of up to 200 electrons. For the quasiholes our results confirm that the charge and statistics parameter are e/3 and 1/3, respectively. For the quasielectron charge we find a slow convergence towards the expected value of -e/3, with a finite size correction for N electrons of approximately -0.13e/N. The statistics parameter for the quasielectrons has no well defined value even for 200 electrons, but might possibly converge to 1/3. The anyon model works well for the quasiholes, but requires singular two-anyon wave functions for modelling two Laughlin quasielectrons.

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