Extending density matrix embedding: A static two-particle theory

We introduce extended density matrix embedding theory (EDMET), a static quantum embedding theory explicitly self-consistent with respect to local two-body physics. This overcomes the biggest practical and conceptual limitation of more traditional one-body embedding methods, namely the lack of screening and treatment of longer-range interactions. This algebraic zero-temperature embedding augments a local interacting cluster model with a minimal number of bosons from a description of the full system correlations via the random phase approximation, and admits an analytic approach to build a self-consistent Coulomb-exchange-correlation kernel. For extended Hubbard models with nonlocal interactions, this leads to the accurate description of phase transitions, static quantities, and dynamics. We also move towards ab initio systems via the Parriser-Parr-Pople model of conjugated coronene derivatives, finding good agreement with experimental optical gaps.

Automated summary

Extended Density Matrix Embedding Theory (EDMET) overcomes the limitations of traditional embedding methods by self-consistently treating local two-body physics. It accurately describes phase transitions and dynamics, and can provide good agreement with experimental results for ab initio systems.