Seminar on Quantum Field Theory, Gravitation, and Elementary Particles

Prof. S. Hollands
Prof. R. Verch

Dr. J. Zahn

Monday, 15:15 – 16:45 (1 hour talk, followed by questions), seminar room 210 ITP
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Schedule for the summer term 2018:

Date Speaker Title (hover/click for abstract)
09.04. no seminar
16.04. Ludwig Hoffmann (ITP)
23.04. Maik Wessling (ITP)
30.04. no seminar
07.05. Jisuke Kubo (Kanazawa)
21.05. public holiday
28.05. Marek Kozon (ITP)

Schedules of past terms:

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Abstract: In most classical field theories the total mass of a system is defined using the stress-energy tensor. However, in general relativity this definition ceases to work. The difficulties arise because there is no stress-energy tensor for the gravitational field and thus the total mass has to be defined otherwise. By introducing a convenient coordinate system (Bondi coordinates) far away from the system it is possible to find a satisfying description of the total mass. Building on previous results in even dimensions we show how the Bondi mass is defined in odd dimensions.
Abstract: We propose a conjecture: For analytic FLWR spacetimes (i.e. with analytic expansion factor a(t)), the construction method for states of low energy (SLEs) produces states that satisfy the analytic microlocal spectrum condition, if an analytic smearing function f(t) is used in their construction. Because proving the conjecture was found to be not fitting the framework of a master thesis we rather do a consistency check. We proceed to construct SLEs for the Klein-Gordon field in deSitter spacetime while specifying the mass of the Klein-Gordon field and the form of the smearing function. It is then shown that the difference of two SLEs – expressed as two-point functions – behaves analytically.
Abstract: We assume that the electroweak scale is generated in a hidden sector which is described by a non-abelian gauge theory. The non-perturbative effect in the hidden sector generates dark matter as well. Since this dynamical scale genesis appears as a first-order phase transition at finite temperature, it can produce a gravitational wave background.
Abstract: tba