The Dirac–Frenkel Principle for Reduced Density Matrices, and the Bogoliubov–de Gennes Equations
The Dirac–Frenkel Principle for Reduced Density Matrices, and the Bogoliubov–de Gennes Equations
The derivation of effective evolution equations is central to the study of non-stationary quantum many-body systems, and widely used in contexts such as superconductivity, nuclear physics, Bose–Einstein condensation and quantum chemistry. We reformulate the Dirac–Frenkel approximation principle in terms of reduced density matrices and apply it to fermionic and bosonic …