Autorenname: Stefan Brackertz

Building quantum space-time with spin foams

Informal Discussion with interested students
Thursday, July 11, 11:00
KOSMA-Room (meeting in foyer)

Talk in Theory Colloquium
Friday, July 12, 16:30
Seminar room ETP

 

Spin foam quantum gravity is a non-perturbative, background independent approach to quantizing gravity. It formulates a path integral as a sum over quantum geometries encoded in group theoretic data as in loop quantum gravity; thus it is frequently seen as a way of defining a covariant dynamics for this theory. In this talk, Sebastian Steinhaus from Jena wants to motivate quantum gravity as a manifestly background independent theory and define the gravitational path integral à la spin foams. As a regularisation, he introduces a triangulation and discuss how gravity can be formulated in the discrete, via Regge calculus in a piece-wise flat way. Then he discusses how quantum geometry is encoded in a spin foam and how it connects to Regge calculus in a putative semi-classical limit. He will review outstanding research challenges, in particular for the Lorentzian theory, and discuss concretely the construction of a cosmological model coupled to a scalar field.

GPK: Hot QCD matter flowing as a fluid


Tuesday, 4th of June, 16.00
(16.00 Coffee & Cake in the foyer, 16.30 talk & discussion)
Lecture Hall III

Very high energy densities are reached in ultra-relativistic collisions of heavy ions. Under these conditions, the confinement in strongly-interacting matter is lifted, and a quark-gluon plasma (QGP) is formed. At the highest temperatures realized in the laboratory, this system offers us the opportunity to study QCD matter under extreme conditions.

The successful heavy-ion program at the LHC provides data of increasing precision. Silvia Masciocchi (Universität Heidelberg und GSI Darmstadt) will illustrate how experimental evidence supports the description of the QGP by fluid dynamics. This description together with neural networks and Bayesian inference allow to determine fundamental properties of QCD with increasing precision.

Full announcement

Solidarität mit Nancy Fraser // Solidarity with Nancy Fraser

Die Fachschaft Physik unterstützt den folgenden offenen Brief von Wissenschaftler*innen gegen die Ausladung von Nancy Fraser:

An die Senator*innen und den Rektor der Universität zu Köln

Die Universität zu Köln hatte die renommierte feministische Philosophin Prof. Nancy Fraser im Jahr 2022 eingeladen, die Albertus-Magnus-Professur an der Universität zu Köln im Jahr 2024 anzunehmen. Nancy Fraser ist eine US-amerikanische Philosophin, kritische Theoretikerin, Feministin und Henry A. und Louise Loeb Professorin für Politik- und Sozialwissenschaften und Professorin für Philosophie an der New School in New York City. Weithin bekannt für ihre Kritik an der Identitätspolitik und ihre philosophische Arbeit über das Konzept der Gerechtigkeit, ist Fraser auch eine entschiedene Kritikerin des zeitgenössischen liberalen Feminismus und dessen Abkehr von Fragen der sozialen Gerechtigkeit. Sie sollte für ihre Arbeiten mit der Kölner Gastprofessur ausgezeichnet werden.

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Vollständiger Brief mit der Möglichkeit selbst zu unterzeichnen

 The Physics Student Council supports the following open letter against the cancellation of Nancy Fraser:

To the Senators and the Rector of the University of Cologne

In 2022, the University of Cologne invited the renowned feminist philosopher Prof. Nancy Fraser to accept the Albertus Magnus Professorship at the University of Cologne in 2024. Nancy Fraser is an American philosopher, critical theorist, feminist, and Henry A. and Louise Loeb Professor of Political and Social Science and Professor of Philosophy at the New School in New York City. Widely known for her critique of identity politics and her philosophical work on the concept of justice, Fraser is also a staunch critic of contemporary liberal feminism and its abandonment of social justice issues. She was to be awarded the Cologne Visiting Professorship for her work.

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Full letter with the possibility to sign the open letter