Quasiparticle Coupled Cluster Theory for Pairing Interactions

Abstract

We present an extension of the pair coupled cluster doubles (p-CCD) method to quasiparticles and apply it to the attractive pairing Hamiltonian. Near the transition point where number symmetry gets spontaneously broken, the proposed BCS-based p-CCD method yields significantly better energies than existing methods when compared to exact results obtained via solution of the Richardson equations. The quasiparticle p-CCD method has a low computational cost of $\mathcal{O}(N^3)$ as a function of system size. This together with the high quality of results here demonstrated, points to considerable promise for the accurate description of strongly correlated systems with more realistic pairing interactions.

References in corpus (2)

• Ab initio Bogoliubov coupled cluster theory for open-shell nuclei
• Accuracy of BCS-based approximations for pairing in small Fermi systems

Cited by in corpus (8)

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• Ab initio Bogoliubov coupled cluster theory for open-shell nuclei
• Symmetry broken and restored coupled-cluster theory I. Rotational symmetry and angular momentum
• Lie Algebraic Similarity Transformed Hamiltonians for Lattice Model Systems
• Many-body computations by stochastic sampling in Hartree-Fock-Bogoliubov space
• Combining symmetry breaking and restoration with configuration interaction: a highly accurate many-body scheme applied to the pairing Hamiltonian
• Extension of time-dependent Hartree-Fock-Bogoliubov equations