|Ph.D Student||Eran Rosenthal|
|Subject||The Self Force in Curved Spacetime|
|Department||Department of Physics||Supervisor||Full Professor Ori Amos|
This research includes two main topics: first, a consistent formulation of the extended-object approach for the explanation and calculation of the self-force phenomenon in flat spacetime. In this approach, one considers a charged extended-object of a finite size that accelerates in a nontrivial manner, and calculates the total force exerted on it by the electromagnetic field (whose source is the charged object itself), at the limit . Previous study of this approach ended up with expressions for the total electromagnetic force that do not have the form required by mass-renormalization (in the special case of a spherical charge distribution, this term was found to be 4/3 times larger than the desired quantity). In this thesis we use energy-momentum conservation in the object's momentary rest frame, and derive the correct notion of total electromagnetic force. This completely cures the problematic O(1/) term, for any object's shape, and yields the correct self-force at the limit .
In particular, for a spherical charge distribution, the above ''4/3 problem'' is resolved.
The second topic in this research is the derivation and implementation of a new regularization approach for the calculation of the scalar self-force in curved spacetime.
In this approach the scalar self-force in curved spacetime is expressed in terms of the difference between two retarded scalar fields: the massless scalar field, and an auxiliary massive scalar field. This field difference combined with a certain limiting process gives a simple expression for the scalar self-force. We implement this approach in the special case of static particle in a Schwarzschild spacetime, thereby we show that the scalar self-force vanishes in this case.