Mathematical analysis of the photoelectric effect

We study the photoelectric effect on the example of a simplified model of an atom with a single bound state, coupled to the quantized electromagnetic field. For this model, we show that Einstein's prediction for the photoelectric effect is qualitatively and quantitatively correct to leading order in the coupling parameter. More specifically, considering the ionization of the atom by an incident photon cloud consisting of $N$ photons, we prove that the total ionized charge is additive in the $N$ involved photons. Furthermore, if the photon cloud is approaching the atom from a large distance, the kinetic energy of the ejected electron is shown to be given by the difference of the photon energy of each single photon in the photon cloud and the ionization energy.Comment: See also http://www.intlpress.com/ATM

The Integrated Density of States for an Interacting Multiparticle Homogeneous Model and Applications to the Anderson Model

For a system of n interacting particles moving in the background of a ``homogeneous'' potential, we show that if the single particle Hamiltonian admits a density of states, so does the interacting n-particle Hamiltonian. Moreover, this integrated density of states coincides with that of the free particle Hamiltonian. For the interacting n-particle Anderson model, we prove regularity properties of the integrated density of states by establishing a Wegner estimate. Copyright (C) 2009 F. Klopp and H. Zenk

Asymptotic Electromagnetic Fields in Non-relativistic QED: the Problem of Existence Revisited

This paper is devoted to the scattering of photons at electrons in models of non-relativistic quantum mechanical particles coupled minimally to the soft modes of the quantized electromagnetic field. We prove existence of scattering states involving an arbitrary number of asymptotic photons of arbitrarily high energy. Previously, upper bounds on the photon energies seemed necessary in the case of $n>1$ asymptotic photons and non-confined, non-relativistic charged particles.Comment: 12 page

Ionisation by quantised electromagnetic fields: The photoelectric effect

In this paper we explain the photoelectric effect in a variant of the standard model of non relativistic quantum electrodynamics, which is in some aspects more closely related to the physical picture, than the one studied in [BKZ]: Now we can apply our results to an electron with more than one bound state and to a larger class of electron-photon interactions. We will specify a situation, where ionisation probability in second order is a weighted sum of single photon terms. Furthermore we will see, that Einstein's equality $$E_{kin}=h\nu-\bigtriangleup E>0$$ for the maximal kinetic energy $E_{kin}$ of the electron, energy $h\nu$ of the photon and ionisation gap $\bigtriangleup E$ is the crucial condition for these single photon terms to be nonzero.Comment: 59 pages, LATEX2

On the Atomic Photoeffect in Non-relativistic QED

In this paper we present a mathematical analysis of the photoelectric effect for one-electron atoms in the framework of non-relativistic QED. We treat photo-ionization as a scattering process where in the remote past an atom in its ground state is targeted by one or several photons, while in the distant future the atom is ionized and the electron escapes to spacial infinity. Our main result shows that the ionization probability, to leading order in the fine-structure constant, $\alpha$, is correctly given by formal time-dependent perturbation theory, and, moreover, that the dipole approximation produces an error of only sub-leading order in $\alpha$. In this sense, the dipole approximation is rigorously justified.Comment: 25 page

The Integrated Density of States for an Interacting Multiparticle Homogeneous Model and Applications to the Anderson Model

For a system of n interacting particles moving in the background of a ``homogeneous'' potential, we show that if the single particle Hamiltonian admits a density of states, so does the interacting n-particle Hamiltonian. Moreover, this integrated density of states coincides with that of the free particle Hamiltonian. For the interacting n-particle Anderson model, we prove regularity properties of the integrated density of states by establishing a Wegner estimate. Copyright (C) 2009 F. Klopp and H. Zenk