A Note on the Paper "Second Quantization and Representation Theory"

Zenonas Rudzikas

Edward M. Corson

The formalism of the second quantization is developed entirely within the framework of the Dirac-Jordan representation theory. The equivalence of this formalism and the methods of ordinary coordinate-spin space is shown, and the equations of "connection" are fully developed. It is shown that the "creation" and "annihilation" operators, and indeed all operators which do not commute with the quantized Hamiltonian and hence whose representatives cannot be explicitly given in a configuration space of a fixed number of dimensions are easily treated in terms of the general representation theory and arise quite naturally. Both types of statistics are considered, and the Fock-Dirac density matrix and self-consistent field are treated as a simple illustration.

I︠u︡. L. Klimontovich

Richard Becker, G�nther Leibfried

Emilio Artacho, Lorenzo Miláns del Bosch

A tensorial formalism is presented for the general use of nonorthogonal basis sets in quantum mechanics, both in representation theory and in second quantization. The natural formulation of second quantization for nonorthogonal basis sets defined here is shown to be formally very similar to the usual formulation for orthogonal basis sets. The formalism is used to study orthogonality effects in a Hubbard model defined on a semi-infinite lattice.