6 papers
Symmetry-adapted generalised normal-ordered coupled-cluster theory for excited states
Nicholas Lee, David P. Tew, Bang C. Huynh
Ground and excited electronic states in highly symmetric systems typically possess high degrees of spatial degeneracy as a consequence of point-group symmetry. However, many curren…
Non-hermitian Green's function theory with -body interactions: the coupled-cluster similarity transformation
Christopher J. N. Coveney, David P. Tew
We present the diagrammatic theory of the irreducible self-energy and Bethe-Salpeter kernel that naturally arises within the Green's function formalism for a general -body non-h…
Spin-free Generalised Normal Ordered Coupled Cluster
Nicholas Lee, David P. Tew
We present a spin-free, size-extensive, and size-consistent coupled cluster method based on a generalised normal ordered exponential ansatz. This approach is a natural generalisati…
Diagrammatic theory of the irreducible coupled-cluster self-energy
Christopher J. N. Coveney, David P. Tew
Coupled-cluster and Green's function theories are highly successful in treating many-body electron correlation, and there has been significant interest in identifying and leveragin…
Spin coupling is all you need: Encoding strong electron correlation in molecules on quantum computers
Daniel Marti-Dafcik, Hugh G. A. Burton, David P. Tew
The performance of quantum algorithms for eigenvalue problems, such as computing Hamiltonian spectra, depends strongly on the overlap of the initial wavefunction and the target eig…
Multi-reference coupled cluster theory using the normal ordered exponential ansatz
Alexander Gunasekera, Nicholas Lee, David P. Tew
Properly spin-adapted coupled-cluster theory for general open-shell configurations remains an active area of research in electronic structure theory. In this contribution we examin…