Electron propagator theory with the ground state correlated by the coupled-cluster method

1993 ◽  
Vol 48 (S27) ◽  
pp. 67-80 ◽  
Author(s):  
Leszek Meissner ◽  
Rodney J. Bartlett
Keyword(s):  
Ground State ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Coupled Cluster Method ◽  
Electron Propagator ◽  
Propagator Theory

QCD GLUEBALLS WITHIN A COUPLED CLUSTER APPROACH

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1732-1735 ◽  
Author(s):  
D. SCHÜTTE ◽  
A. WICHMANN ◽  
V. WETHKAMP
Keyword(s):  
Field Theory ◽  
Monte Carlo ◽  
Ground State ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Gauge Field Theory ◽  
Coupled Cluster Method ◽  
Cluster Approach ◽  
Monte Carlo Techniques ◽  
Lattice Gauge

The validity of the coupled cluster method is studied within the lattice gauge field theory given by a SU(2) pure glue theory in 2+1 dimensions. Satisfactory convergence is observed for the ground state, but the method is less successful for the prediction of glueballs. We propose to improve the coupled cluster method for excited state by combining it with standard Monte-Carlo techniques which potentially cure the non-hermiticity problems caused by the truncation.

scholarly journals The Coupled Cluster Method Applied to the Spin-Half XXZ Model on the Honeycomb Lattice

1998 ◽  
Vol 12 (23) ◽  
pp. 2371-2383 ◽  
Author(s):  
R. F. Bishop ◽  
J. Rosenfeld
Keyword(s):  
Ground State ◽  
State Energy ◽  
Finite Lattice ◽  
Approximation Schemes ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Series Expansions ◽  
Honeycomb Lattice ◽  
Coupled Cluster Method ◽  
Xxz Model

The coupled cluster method (CCM) is applied to the spin-half XXZ model on the honeycomb lattice. Hierarchical CCM approximation schemes are applied in order to obtain the ground-state properties. The possible critical behavior of this model is also examined. Reasonably good results for the ground-state energy and the staggered magnetization are obtained, in comparison to the results from Monte Carlo simulations, spin-wave techniques, series expansions, and finite lattice diagonalizations, that have already been performed on this model.

scholarly journals ODD AND EVEN BEHAVIOR WITH LSUBm APPROXIMATION LEVEL IN HIGH-ORDER COUPLED CLUSTER METHOD (CCM) CALCULATIONS

2008 ◽  
Vol 22 (20) ◽  
pp. 3369-3379 ◽  
Author(s):  
D. J. J. FARNELL ◽  
R. F. BISHOP
Keyword(s):  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Computational Techniques ◽  
Great Success ◽  
Coupled Cluster Method ◽  
Expectation Values ◽  
Sublattice Magnetization

The coupled cluster method (CCM) is a powerful and widely applied technique of modern-day quantum many-body theory. It has been used with great success in order to understand the properties of quantum magnets at zero temperature. This is largely due to the application of computational techniques that allow the method to be applied to high orders of approximation using a localized scheme known as the LSUBm scheme. A hitherto unreported aspect of this scheme is that results for LSUBm expectation values behave in distinctly different ways with odd and even values of m. Here, we consider the behavior of ground-state expectation values of odd and even orders of the CCM LSUBm approximation for unfrustrated spin-half Heisenberg antiferromagnets on the square and honeycomb lattice and the frustrated spin-half Heisenberg antiferromagnet on the triangular lattice. We demonstrate that results for odd and even orders of approximation show qualitatively different behavior for both the ground-state energy and the sublattice magnetization. Indeed, the odd series consistently forms an upper branch of results, and the even series a lower branch with respect to both ground-state energy and sublattice magnetization, for all of the models considered here.

Profiling the binding motif between Be and Mg in the ground state via a single-reference coupled cluster method

2015 ◽  
Vol 113 (12) ◽  
pp. 1387-1395 ◽  
Author(s):  
Uttam Sinha Mahapatra ◽  
Debi Banerjee ◽  
Rajat K Chaudhuri ◽  
Sudip Chattopadhyay
Keyword(s):  
Ground State ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Binding Motif ◽  
Coupled Cluster Method
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