Oberseminar Mathematische Physik
im Wintersemester 2017/2018 von Prof. Dr. D. Dürr, Prof. Dr. P. Pickl und
Dirk  André Deckert
The seminar is usually on Wednesdays, 16:15h, in room B004.
Talks
Date 
Room 
Title 
Speaker 

Wed 18.10.17, 16:15 
B004 
The Method of Epstein and Glaser applied to external field QED, part 2 
Markus Nöth 
Wed 25.10.17, 16:15 
B004 
Defense: Arrival Time Distributions of spin1/2 Particles 
Siddhant Das 
Wed 01.11.17, 16:15 
B004 
No seminar  Allerheiligen 
 
Wed 08.11.17, 16:15 
B004 
Propagation of chaos in the VlasovPoisson system 
Philipp Grass 
Wed 15.11.17, 16:15 
B004 
Bose Einstein Condensation in attractive systems 
Maximilian Jeblick 
Wed 22.11.17, 16:15 
B004 
Interior boundary conditions for multitime wave functions, or: Creating and annihilating Dirac particles in 1D without infinities 
Lukas Nickel 
Wed 29.11.17, 16:15 
B004 
Mathematical Foundations of the Statistical Analysis in Physics 
Paula Reichert 
Wed 06.12.17, 16:15 
B004 
GhirardiRiminiWeber model with massive flashes
I will introduce a modification of the GhirardiRiminiWeber (GRW) model in which the flashes (or collapse spacetime events) source a classical gravitational field. The resulting semiclassical theory of Newtonian gravity preserves the statistical interpretation of quantum states of matter in contrast with mean field approaches. It can be seen as a discrete version of recent proposals of consistent hybrid quantum classical theories. The model is in agreement with known experimental data and introduces new falsifiable predictions: (1) particles do not attract themselves, (2) the 1/r gravitational potential of Newtonian gravity is cutoff at short (. 10−7m) distances, and (3) gravity makes spatial superpositions decohere at a rate inversely proportional to that coming from the vanilla GRW model. Together, the last two predictions make the model experimentally falsifiable for all values of its parameters. 
Antoine Tilloy 
Wed 13.12.17, 16:15 
B004 
CANCELLED! Guest cannot come due to bad weather 
 
Wed 20.12.17, 16:30 
B448 
End of the year session
In absence of a speaker, we will consider a celebratory model for prechristmas dynamics of many interacting group members. The effect of cookies and the consumption of warm liquids on the social behaviour of mathematicians will be empirically tested. All group members are invited! 
 
Wed 10.01.18, 16:15 
B004 
How electrons spin
There are a number of reasons to think that the electron cannot truly be spinning. Given how small the electron is generally taken to be, it would have to rotate superluminally to have the right angular momentum and magnetic moment. Also, the electron’s gyromagnetic ratio is twice the value one would expect for an ordinary classical rotating charged body. These obstacles can be overcome by examining the flow of mass and charge in the Dirac field (which gives the classical state of the electron). Superluminal velocities are avoided because the electron’s mass and charge are spread over sufficiently large distances that neither the velocity of mass flow nor the velocity of charge flow need to exceed the speed of light. The electron’s gyromagnetic ratio is twice the expected value because its charge rotates twice as fast as its mass. 
Charles "Chip" Sebens 
Wed 17.01.18, 16:15 
B004 
Asymptotic completeness in dissipative scattering theory 
Jérémy Faupin 
Wed 24.01.18, 16:15 
B004 
tba 
Alexandra Landsman 
Wed 31.01.18, 16:15 
B004 
Interacting particles in R^d at low temperatures: towards phase
transitions and metastability
Phase transitions for lattice systems such as the Ising
model are wellunderstood. For particles in R^d, the situation is much
less satisfying and the existence of phase transitions has been proven
only for some models, notably the WidomRowlinson model and Kac
interactions (Lebowitz, Mazel, Presutti) model. I will present some
results on the lowtemperature behavior of classical Gibbs measures
motivated by the search for phase transitions, and for a concrete
model sketch some results on continuum Glauber dynamics at low
temperature in finite volume, specifically Arrhenius law and
nucleation barriers. Based on work with F. den Hollander, W. König, B.
Metzger. 
Sabine Jansen 
Wed 07.02.18, 16:15 
B004 
Loop measures and isomorphism theorems for spacetime random walks
Loop measures have become important in the analysis of random walks and their applications in mathematical physics and are currently actively worked on. Such measures go back to Symanzik in the late 1960s in the context of Euclidean field theory. We introduce a novel class of such measures  namely loop measures on graphs with countable infinite different time horizons. The loops are generated by spacetime random walks where we add an additional dimension  called ‘time’  to the integer lattice in d dimension, d >= 3. These measures are connected to the cycle representation of partition functions in quantum systems (Boson systems). We derive corresponding Dynkin isomorphism theorems for spacetime random walks which are complex Gaussian measures and we show the onset of the socalled BoseEinstein condensation for some examples using the Green function analysis for spacetime random walks. Joint work with Q. Vogel.

Stefan Adams 
Organisation of the Oberseminar:
Lukas Nickel. Just write me an email with any questions or requests or if you would like to present.
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