Hideki Koizumi

Exact relations for two-dimensional electron gas spin correlation functions

Abstract Using the non-perturbative method we discuss the virial theorem with a spin correlation term, the translational invariance of the spin correlation function and the f-sum rule for the spin response function.

An extension of the Avron-Herbst transformation to the quantized Schrödinger field for an interacting many-electron system

The effect of a uniform electric field on the time evolution of a single-electron wavefunction can be rigorously expressed by making use of the Avron-Herbst transformation. We extend the transformation to the quantized Schrodinger field for a many-electron system with an electron-electron interaction. The transformation for the time-ordered product of the Schrodinger field, which is the operator part of the Green function, is also derived.

New Canonical Transformations to Eliminate External Fields in Quantum Many-Body Problems

The wave function of an electron in a time varying electric field, a static magnetic field and a impurity potential can be transformed to the wave function of an electron without the electric field. By a unitary transformation, the electric field can be rigorously eliminated.