Graduate Seminar, 21st March

Speaker: Artur Miroszewski

Title: Affine quantization of FRW universe and some cosiderations about semiclassical analysis

Abstract: In my talk I will introduce phenomenological method appropriate to deal with quantum systems originating from classical systems defined on half-plane phase space. In order to use the mentioned method I will present theory of affine coherent states and integral quantization. By applying affine quantization (affine coherent states integral quantization) to FRW universe we will get one of the well estabilished results of quantum cosmology- initial singularity avoidance. By rough semiclassical analysis we will get some properties of the Big Bounce. I will end my talk by presenting some ideas to improve semiclassical analysis by using coherent states.

Graduate Seminar, 14th March

Speaker: Albin Nilsson

Title: Constraining Lorentz Invariance Violating Scenarios in Rainbow Gravity by Cosmological Data

Abstract: The standard relativistic dispersion relation is modified to break Lorentz symmetry, which is predicted in the high-energy regime of certain theories of quantum gravity. We show that is it possible to realise this scenario in the framework of Rainbow Gravity. We also derive the modified Friedmann-Lemaitre-Robertson-Walker (FLRW) equations and show that these lead to a change in the standard expression for luminosity distance. $G$ and $\Lambda$ are assumed to be energy dependent; we give two explicit examples of this and constrain these functions using the Union2.1 Sn1a dataset. We also consider a more general case with an undefined function and obtain constraints on its magnitude.

For more details please see https://arxiv.org/abs/1701.00533

Graduate seminar, 7th March

Speaker: Piotr Warzybok

Title: The 316L steel SLM 3D printing process and the fabricated material physical properties.

Abstract: One of the techniques of additive manufacturing is the SLM (Selective Laser Melting) technology. In this method, an object is created by selectively fusing thin layers of powder using a scanning laser beam according to CAD data of the part. SLM in known since the ‘90s and the recent efforts have improved this technique considerably, but still many problems handicapping the successful fabrication of high-quality metal parts with desired microstructures and properties do exist. Physical phenomena during the process of 3D printed parts will be reviewed. The most important physical parameters of the 3D printed metal models will be discussed. The future goals of my research will be defined.