NONLINEAR PROCESSES OF QUANTUM ELECTRODYNAMICS
(QED) IN THE ELECTRIC FIELDS OF HEAVY ATOMS
Prof. Alexander I. Milstein
Budker Institute of Nuclear Physics, Novosibirsk
School of Physics Common Room
Room 64, Old Main Building
Date:
4.00 - 5.00 p.m., Thursday, 13th
September, 2001
The audience, including graduate
students, are invited to meet the speaker 15 minutes beforehand
over wine and cheese in the Physics Common Room.
Outline
Since the photon has no electric charge,
it cannot interact directly with an electric or magnetic field.
However, in quantum electrodynamics a photon has non-zero probability
to transfer to a virtual electron-positron pair which interacts
with the electromagnetic field, and then annihilate into arbitrary
number of final photons. As a result, there is an elastic scattering
of a photon in the electromagnetic field (Delbrück scattering),
as well as the photon splitting into two photons.
Photon splitting in a magnetic field
is of great importance for the radiation from pulsars. Photon splitting
in the electric field was discovered only very recently in an experiment
performed in the Budker Institute of Nuclear Physics.
In my talk I discuss results of recent
theoretical and experimental investigations of Delbrück scattering
in the electric field of a heavy atom as well as photon splitting
in this field. The investigation of these nonlinear QED processes
is important as a new test of QED. It also gives a possibility to
understand the role and the structure of higher orders of perturbation
theory with respect to the external field since the exact cross
sections differ essentially from that obtained in the lowest approximation.
Further Information
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