  Computationally efficient and accurate quantum mechanical approximations to
solve the many-electron Schr\"odinger equation are at the heart of
computational materials science. In that respect the coupled cluster hierarchy
of methods plays a central role in molecular quantum chemistry because of its
systematic improvability and computational efficiency. In this hierarchy,
coupled cluster singles and doubles (CCSD) is one of the most important steps
in moving towards chemical accuracy and, in recent years, its scope has
successfully been expanded to the study of insulating surfaces and solids.
Here, we show that CCSD theory can also be applied to real metals. In so doing,
we overcome the limitation of needing extremely large supercells to capture
long range electronic correlation effects. An effective Hamiltonian can be
found using the transition structure factor--a map of electronic excitations
from the Hartree--Fock wavefunction--which has fewer finite size effects than
conventional periodic boundary conditions. This not only paves the way of
applying coupled cluster methods to real metals but also reduces the
computational cost by two orders of magnitude compared to previous methods. Our
applications to phases of lithium and silicon show a resounding success in
reaching the thermodynamic limit, taking the first step towards a truly
universal quantum chemical treatment of solids.
