The main goal of the project is to arrive at a fully consistent quantum mechanical description of the evolution of the matter-antimatter asymmetry in the universe

• Applicant: Dr. Michael Martin Plümacher
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: from 2005 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5443828

The preponderance of matter over antimatter in the universe is a long-standing cosmological problem. The recent experimental evidence for non-zero neutrino masses has boosted confidence that the mechanism of "leptogenesis", which relates properties of light neutrinos to the cosmological matter-antimatter asymmetry, is the correct explanation. As a consequence, neutrino masses must satisfy strict upper limits in accord with current measurements and within reach of future laboratory experiments and observational cosmology. The theory of leptogenesis connects several areas of leading-edge research, i.e. experimental and theoretical neutrino physics, early-universe cosmology, and thermal quantum field theory. State-of-the-art leptogenesis calculations of the production of a matter-antimatter asymmetry during the evolution of the early universe rely on approximations where potentially important quantum and thermodynamical corrections are omitted. The goal of the proposed research is to progress beyond this approximation and arrive at a fully consistent quantum mechanical description. The time evolution of a many-particle quantum system away from thermal equilibrium can be consistently described in the Schwinger-Dyson formalism. This formalism will be systematically studied and applied to early-universe cosmology. A complementary goal of the proposal is to further study the phenomenological implications of the leptogenesis mechanism for low-energy physics. This is particularly relevant in view of current and future particle physics and neutrino experiments that may provide interesting constraints on leptogenesis.

• DFG Programme: Independent Junior Research Groups