Coupled Cluster Green's function formulations based on the effective Hamiltonians

A Modified Coupled - Cluster Based Investigation of Delo - calization in Tight - Binding Hamiltonians

– The nature of delocalization in a 1D system ruled by a tight-binding Hamiltonian is investigated. Using a local evaluation of the ground state energy, it is shown that the range of the delocalization effects is rather limited. The method is applied to 1/2 and 1/4 filled systems. Introduction. – For the last few decades, physicists and chemists have put a lot of effort into understanding the p...

Bounds on Effective Hamiltonians for Stabilizer Codes

This manuscript introduces various notions of k-locality of stabilizer codes inherited from the associated stabilizer groups. A choice of generators for the group leads to a Hamiltonian with the code in its groundspace, while a Hamiltonian holding the code in its groundspace might be called effective if its locality is less than that of a natural choice of generators (or any choice). This paper...

Effective Hamiltonians with Relativistic Corrections

Seniority-based coupled cluster theory.

Doubly occupied configuration interaction (DOCI) with optimized orbitals often accurately describes strong correlations while working in a Hilbert space much smaller than that needed for full configuration interaction. However, the scaling of such calculations remains combinatorial with system size. Pair coupled cluster doubles (pCCD) is very successful in reproducing DOCI energetically, but ca...

Optimal control of effective Hamiltonians.

We present a systematic scheme for the optimization of quantum simulations. Specifically, we show how polychromatic driving can be used to significantly improve the driving of Raman transitions in the Lambda system, which opens new possibilities for controlled driving-induced effective dynamics.