Research Profile

The MPI für Kernphysik performs both experimental and theoretical basic research in two interdisciplinary research fields:

crossroads of particle physics and astrophysics (astroparticle physics) and
many-body dynamics of atoms and molecules (quantum dynamics).

Presently, there are five divisions with the directors

• Prof. Dr. Klaus Blaum (stored and cooled ions),
• Prof. Dr. Werner Hofmann (particle physics and high-energy astrophysics),
• Hon. Prof. Dr. Christoph H. Keitel (theoretical quantum dynamics in intense laser fields),
• Prof. Dr. Manfred Lindner (particle and astroparticle physics),
• Prof. Dr. Joachim H. Ullrich (on leave of absence; acting: Prof. Dr. K. Blaum) (experimental few-particle quantum dynamics),

and additionally five junior groups and further research groups.

Astroparticle Physics

The research in high-energy astrophysics at MPIK is focused on the observation of very-high-energy photons – the gamma radiation – from the cosmos using the H.E.S.S. telescope system in Namibia. Cosmic particle accelerators can be traced and investigated using this gamma radiation. The location on the southern hemisphere also enables a direct view onto the particularly fascinating center of the Milky Way. The observations with H.E.S.S. show for the first time, that in our galaxy there are numerous sources of such high-energy radiation and thus open a new window onto the universe.

The closely correlated theoretical work deals with the operating mode of cosmic accelerators and the production of gamma rays in collisions of the accelerated elementary particles with interstellar matter.
Further astrophysical work deals with observations of the interstellar and intergalactic dust in the far infrared spectrum, as well as with its examination by dust detectors onboard spacecraft in the solar system.

The theoretical work on particle and astroparticle physics is concerned with phenomenological questions about neutrino physics, the nature of dark matter and dark energy, and their cosmological implications, e.g., immediately after the Big Bang. Combining the results from neutrino physics, astroparticle physics, and accelerator experiments provides direct and indirect evidence for the physics beyond the standard model of particle physics. Our goal is a deeper understanding of the fundamental laws of nature.
One of these fundamental questions – the origin of the asymmetry between matter and antimatter – is investigated by researchers at the MPIK in the framework of the LHCb experiment at the Large Hadron Collider of CERN in Geneva. The nature of the Dark Matter in the Universe, probably weakly interacting massive particles, is explored at largely increased sensitivity by the next-generation liquid-noble-gas experiment XENON.

Scientists at the MPIK presently participate in 4 international large-scale experiments in neutrino physics. Since spring 2007, the solar neutrino detector Borexino is taking data in the Gran-Sasso underground laboratory in Italy, where also GERDA, an experiment searching for the neutrinoless double-beta decay in Germanium crystals is under construction. From 2009 on, the neutrino-oscillation experiment Double Chooz will use neutrinos from a nuclear power plant in France to investigate the periodic interchange between the 3 neutrino types.

Quantum Dynamics

In the microcosm, the world of elementary particles, atoms and molecules, the laws of quantum theory with their fascinating effects are valid.

The work on theoretical quantum dynamics is focused on calculations of the interaction of atoms or molecules with highly intense laser fields. In these fields particles become so fast, that the effects of Einstein‘s theory of Special Relativity play an important role. In extremely strong fields, nuclear-physics processes may actually occur and new particles may be formed; in addition it turns out that the vacuum is not empty. In the framework of quantum electrodynamics, the most precise theory we have in physics, the “structure of the vacuum” is described, and their predictions are scrutinized with the highest precision using ion traps at the MPIK like the EBIT or Penning traps.

Using reaction microscopes, which have been developed at the MPIK, it is possible to observe how molecules vibrate, rotate, and even how they move in the course of a chemical reaction. This happens within a few femtoseconds: a millionth of a part in a billion of a second. Such short light pulses are readily available in the laser laboratories at the MPIK. Even shorter time spans, during which light covers only atomic-diameter distances, can be achieved by the bombardment of atoms or molecules with fast charged particles, e.g., at the accelerator facilities of GSI in Darmstadt. Additional experiments with ultra-short X-ray pulses are performed at the FLASH of DESY in Hamburg, the first free-electron laser worldwide.

The MPIK operates facilities for the generation and storage of ions – electrically charged atoms or molecules: The accelerators, the test storage ring (TSR), electron-beam ion traps (EBIT) and precision Penning traps. Using these devices it is possible to determine fundamental properties of trapped “hydrogen-like” ions (atoms with only one electron left) with a high accuracy. Extremely precise mass measurements of single atomic nuclei that are only stable for a short period of time and then decay, help us to understand various aspects of fundamental physics. For example, how have heavy elements been formed and why do we see the given abundancies of elements in the universe? Last but not least these measurements are vital for the determination of natural constants and for the examination of the standard model of particle physics.

A new, worldwide unique, cryogenic storage ring (CSR) is under construction, which will be operated at a temperature of only a few degrees above absolute zero, and allowing us to create for the first time conditions on earth, that prevail in interstellar clouds, for example. Here complex molecules will be observed, simple building blocks of life, and the researchers aim to understand, how these can be formed in the vastness of space.

Even lower temperatures are accessible by means of laser cooling in specially designed atom traps. So it is possible to produce and investigate so-called quantum gases (e.g., Bose Einstein condensates), millimeter-sized atomic clouds representing one macroscopic quantum state. The MPIK has initiated the FLAIR project at GSI, where antimatter in quantities not previously achievable shall be produced, stored and investigated in detail, in order to find out more about its fascinating properties.