Two seminars on Gravitational Waves and Wigner’s friends

ICTQT Seminar 

Date: March 25th, 2022
Time: 11:00
Speaker: Sebastian Szybka (Jagiellonian University)

Examples of standing gravitational waves in general relativity

Place: room 42, ICTQT (Jana Bażyńskiego 1A)

Abstract: Standing waves are a quite common phenomenon in physics. They are well understood in linear theories. In Einstein’s gravity, which is a nonlinear theory, the lack of superposition principle complicates studies. I will present exact solutions to Einstein equations that correspond to standing gravitational waves. They provide useful toy-models that allow to investigate the phenomenon.

IFTiA Seminar 

Date: March 25th, 2022
Time: 12:15
Speaker: Marcin Markiewicz  (ICTQT)

Physics and Metaphysics of Wigner’s Friends

Link: https://zoom.us/j/99966969172?pwd=MkdzN05UaGxyZFZHdXJCWStZT1FVQT09

Abstract: Recently there appeared many works on modified Wigner’s Friend paradoxes, which suggest that quantum theory cannot consistently describe the scenario with many observers. In this presentation I will show an alternative approach to this problem, which indicates that the paradoxes are in fact apparent, and the source of confusion is the undefined status of the measurement process. The talk will be based on recently published work „Physics and Metaphysics of Wigner’s Friends: Even Performed Premeasurements Have No Results” by Marek Żukowski and Marcin Markiewicz, Phys. Rev. Lett. 126, 130402 (2021).