Seminars for the year:
2025
2024
2023
2022
2021
2020
2019
2018
2017
2016
2015
2014
2013
2012
2011
2010
2009
2008
2007
Follow our seminars online via: GPF BigBlueButton server
Time: 21. February 2025, 11:00h
Place: Institute of Physics, room 360
Speaker: Tijana Radenkovic
Title: 3BF teorija kao topološka kvantna teorija polja
Abstract:
We study the path integral quantization of the topological 3BF theory, whose gauge symmetry is described by a 3-group. This theory is relevant for the quantization of general relativity coupled to Standard Model of elementary particles. We explicitly construct a state sum corresponding to the discretized path integral of a 3BF action. Being a topological invariant of 4-dimensional manifolds with boundary, this state sum gives rise to a topological quantum field theory (TQFT), realized as a functor between the category of cobordisms and the category of Hilbert spaces. After an introduction to appropriate category theory concepts and the construction of the state sum, we provide an explicit proof that it satisfies all Atiyah's axioms, and thus represents a genuine TQFT. The formulation of this TQFT represents a major step in the spinfoam quantization programme for a realistic theory of quantum gravity with matter.
Time: 14. February 2025, 11:00h
Place: Institute of Physics, room 360
Speaker: Dusan Djordjevic
Title: QFT on fuzzy AdS spaces: classical limit and boundary correlation functions
Abstract:
AdS spacetime, a maximally symmetric solution of Einstein's equations with a negative cosmological constant, has gained enormous interest because of its space-like boundary and relation with holographic duality (AdS/CFT). In this talk, we will consider fuzzy AdS space in two and three dimensions and analyze the scalar field propagating on top of this quantum spacetime. We will introduce the notion of semi-classical states, enabling us to discuss fuzzy generalizations of classical points and boundaries. Establishing the boundary behavior of the scalar field and the classical limit of fuzzy spacetime, we will proceed to analyze quantum fields, obtaining the expression for correlation functions of operators dual to this scalar field at the boundary.
Time: 7. February 2025, 11:00h
Place: Faculty of Physics, room 661
Speaker: Igor Salom
Title: Mesaurement problem in quantum mechanics and the hard problem of consciousness
Abstract:
The topic of the lecture is understanding quantum mechanics, or rather, examining its deepest problem - the "measurement problem". For this reason, we will first carefully examine the so-called "Wigner's friend paradox" - a thought experiment that most profoundly illustrates the famous measurement problem and at the same time represents perhaps the only (potential) quantum-mechanical experiment for which there is no scientific consensus on what the expected outcome is.
Then we will point out the existence of a mapping between interpretations of quantum mechanics and views on the problem of consciousness (and establish a specific "dictionary" between the "hard problem" of consciousness and the "measurement problem" of quantum mechanics). Then we will consider what possibilities quantum mechanics offers to avoid the "hard problem" of consciousness that was the topic of the previous lecture, and argue that this also contains a possible solution to the Wigner's friend paradox. As we shall see, these simultaneous solutions to both major problems of modern science ("hard problem" and "measurement problem") require abandoning the paradigm of materialism, which is still prevalent in the wider scientific community.
Time: 29. January 2025, 13:00h
Place: Faculty of Physics, room 665
Speaker: Maria Del Pilar Garcia Del Moral Zabala
Title: Higher form symmetries of the M2-brane
Abstract:
In this talk I will describe the existence of invertible Higher form symmetries on the M2-brane. I will explain the cancellation of the 't Hooft anomaly and how in the cases of compactified spaces this is related to the existence of a 1-Gerbe structure over the M2-brane that when projected on the spatial part of the worldvolume represents a flux condition. Interestingly, the major part of the sectors of the M2-brane that have been found with good quantum properties are associated to the imposition of a worldvolume flux condition. I will also comment briefly on the extension of these symmetries to the non-invertible case.
Seminars for the year:
2025
2024
2023
2022
2021
2020
2019
2018
2017
2016
2015
2014
2013
2012
2011
2010
2009
2008
2007
Follow our seminars online via: GPF BigBlueButton server
