Correlation-driven phenomena in periodic molecular systems from variational two-electron reduced density matrix theory

Correlation-driven phenomena in molecular periodic systems are challenging to predict computationally not only because such periodically infinite but also they typically strongly correlated. Here we generalize the variational two-electron reduced density matrix (2-RDM) theory compute energies and properties of correlated systems. The 2-RDM unit cell is directly computed subject necessary $N$-representability conditions that unit-cell represents at least one $N$-electron matrix. Two canonical non-trivial systems, metallic hydrogen chains acenes, treated demonstrate methodology. We show that, while single-reference correlation theories do capture strong (static) effects either these predicts Mott metal-to-insulator transition length-dependent polyradical formation acenes. For both acenes calculations compared with previous non-periodic results showing a significant change increase electron from boundary conditions. theory, which allows for much larger active spaces than traditionally possible, applicable studying correlation-driven general solids materials.