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AGPhil: Arbeitsgruppe Philosophie der Physik

AGPhil 3: Particles and Fields

AGPhil 3.1: Vortrag

Montag, 15. März 2010, 15:20–15:50, JUR G

The Appearence of Mass in Fundamental Theories of Physics — •Harald Markum — Atominstitut, Vienna University of Technology, Austria

In Classical Newtonian Mechanics the Hamiltonian function consists of a sum of kinetic and potential energy, where the mass of a body enters as a parameter. Within gravity one does not distinguish between gravitational mass in the attraction of bodies in contrast to the inertial mass of objects in empty space; experimentally no difference can be found. In Special Theory of Relativity there appears the energy-momentum relation, where the value of the mass depends on the velocity; the rest mass is the same parameter as in Classical Mechanics.

In Quantum Mechanics the mass stays as a parameter in the Hamiltonian; excited states in the Hydrogen atom are proportional to the rest masse. In Quantum Field Theory the mass becomes a (divergent) parameter, which has to be fixed to the experimental value via a renormalization procedure.

In the Standard Model of Particle Physics the masses depend on the vacuum expectation value of the Higgs Field. The fermions are additionally influenced from a Yukawa Coupling, being an open parameter. The mechanism which gives the proton its mass from the three quarks and the gluon field is an actual research topic. Neutrinos have a finite mass but their sizes have not been measured.

In the Three Body Problem the mass of the interacting particles plays a decisive role; in general such systems are chaotic. In Astrophysics we are confronted with the problem of dark mass and dark energy. We give an overview of the different definitions and measurements.