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Colloquium

Topic:

Der Dual Fluid Reaktor - neue Reaktortechnik zum Lösen unserer Energieprobleme

Date:

31.01.23

Time:

14:15

Place:

H6

Guest:

Nico Bernt

Dual Fluid Energy Inc., Vancouver, Canada

Abstract:

Als Einstieg begründe ich kurz die volkswirtschaftliche Daseinsberechtigung der Kernenergie auf Basis der ingenieurswissenschaftlichen Parameter (Energiedichte, EROI, Verfügbarkeit). Anschließend gebe ich einen kurzen Abriss zur bestehenden Kernspaltungsreaktortechnik und betrachte die Energieaufwendungen im Lebenszyklus aktueller Leichtwasserreaktoren. Im weiteren Fortgang komme ich auf alternative Reaktorkonzepte wie den Mono-Fluid-Salzschmelze-Reaktor und die Schnellspaltreaktortechnik zu sprechen. Dieser Abriss führt mich dann direkt zum Dual Fluid Reaktor, dessen Konzept ich, mit seinen essentiellen Vorteilen gegen über den anderen Reaktorkonzepten, vorstellen werde.

Contact person:

J. Schnack

Colloquium Mathematical Physics

Topic:

Causal Fermion Systems and Unitary Group Integrals

Date:

13.01.23

Time:

16:15

Place:

D5-153

Guest:

Felix Finster

Universität Regensburg

Abstract:

The theory of causal fermion systems is an approach to describe fundamental physics. It gives quantum mechanics, general relativity and quantum field theory as limiting cases and is therefore a candidate for a unified physical theory. Moreover, causal fermion systems provide a general framework for modelling and analyzing non?smooth spacetime structures. The dynamics of a causal fermion system is described by a nonlinear variational principle, the causal action principle. In the talk I will give a non?technical introduction. Then I will define the quantum state of a causal fermion system. Its computation involves unitary group integrals. I will show the different integrals and explain the scaling limit which we are interested in. I am reporting on joint work with Niky Kamran and Moritz Reintjes.?

Contact person:

G. Akemann

Seminar High Energy Physics

Topic:

Real-time evolution of a scalar field using the complex Langevin equation

Date:

23.02.23

Time:

14:15

Place:

D6-135

Guest:

Nina Lampl

Universität Graz

Abstract:

Lattice calculations of real-time dynamics in Minkowski space suffer from the so-called sign-problem, which means that there is a non-positive weight in the path integral and thus one cannot use importance sampling. This lack of a well-defined probability measure can be overcome by complexifying the Langevin equation, which is called complex Langevin approach. In this talk I will show results from the Langevin equation for a real-time evolution of a scalar phi^4 theory. This approach however fails for longer time-contours, due to the appearance of long tailed distributions in the solution. This is why the aim is to use the freedoms of the Langevin equation with machine learning techniques in order to achieve a correct result.

Contact person:

W. Unger

Seminar Condensed Matter

Topic:

Approaching the classical limit of Lindblad dynamics - emergence of limit cycles, fixed points and algebraic decay

Date:

27.01.23

Time:

14:15

Place:

D5-153

Guest:

Masudul Haque

TU Dresden

Abstract:

Iconic features of classical dissipative dynamics include persistent limit-cycle oscillations and critical slowing down at the onset of such oscillations, whereby the system relaxes purely algebraically in time. On the other hand, quantum systems subject to generic Markovian dissipation decohere exponentially in time, approaching a unique steady state. Here we show how coherent limit-cycle oscillations and algebraic decay can emerge in a quantum system governed by a Markovian master equation. We illustrate these mechanisms using a single-spin model motivated by Landau-Lifshitz-Gilbert dynamics, and using a bosonic model with dissipation.

Contact person:

FOR2692/Jürgen Schnack

Seminar Mathematical Physics

Topic:

ξ-regularized Lattice Field Theory

Date:

19.01.23

Time:

16:00

Place:

D5-153

Guest:

Tobias Hartung

University of Bath

Abstract:

Contact person:

Gernot Akemann

Seminar Bielefeld-Melbourne Random Matrices

Topic:

tba

Date:

29.03.23

Time:

09:00

Place:

ZOOM / Konferenzschaltung

Guest:

Leslie Molag

Univ. of Sussex

Abstract:

Contact person:

Gernot Akemann



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