Quantum embedding methods are promising for accurately describing electron correlation in molecules and materials, especially when correlated wave-function methods become prohibitively expensive due to their poor scaling with system size. These methods involve dividing a system into important regions (called impurities or fragments) that are treated with a highly correlated theory, while the rest of the system is described using a more approximate level of theory, such as Hartree-Fock (HF) or Kohn-Sham density functional theory. One particular type of quantum embedding method is density matrix embedding theory (DMET), which uses a wave function-in-wave function approach and models the environment of the impurity or fragment using a bath constructed from the Schmidt decomposition of a mean-field wave function.