Sommerfeld Theory Colloquium (ASC)

Ludwig-Maximilians-Universität München

The Arnold Sommerfeld Center for Theoretical Physics organizes regular colloquia about topics of current interest in the field of theoretical physics.

  • 54 minutes 41 seconds
    Tensor Networks and Quantum Computers
    Tensor Network States, like matrix product or projected entangled pair states play an important role in both, quantum information theory and many-body physics. They offer a compact and efficient representation, enabling accelerated numerical computations and providing intuitive insights into many-body phenomena. In this talk, I will discuss how certain states can be efficiently prepared and manipulated using quantum devices, highlighting the use of local operations and classical communication. Tensor networks can also be used to efficiently describe quantum channels. I will also mention how those channels can be efficiently implemented as quantum circuits.
    8 January 2026, 4:55 pm
  • 1 hour 19 minutes
    Planck mission: the 2013 cosmology results
    Sommerfeld Theory Colloquium
    8 January 2026, 2:28 pm
  • 1 hour 11 minutes
    Status of the Electroweak Standard Model
    With the discovery of the Higgs boson and the determination of its mass, the Standard Model is complete and its parameters are now known and over-constrained. I will review the status and future directions in precision electroweak physics both at high and low en- ergies. There is strong evidence that the Standard Model is correct at the level of quantum corrections, and that in the absence of major conspiracies, any new physics beyond it is either significantly heavier than the electroweak scale or very weakly coupled.
    8 January 2026, 2:28 pm
  • 1 hour 6 minutes
    Higher Spin --- CFT duality
    The conjectured relation between higher spin theories on anti de-Sitter (AdS) spaces and weakly coupled conformal �field theories is reviewed. I shall then outline the evidence in favour of a concrete duality of this kind, relating a speci�c higher spin theory on AdS3 to a family of 2d minimal model CFTs. Finally, I shall explain how this relation �ts into the framework of the familiar stringy AdS/CFT correspondence.
    8 January 2026, 2:28 pm
  • 1 hour 8 minutes
    Turbulence without Linear Instability
    All flows show a transition from a laminar phase to a turbulent one for sufficiently high flow speeds. In many cases turbulence develops in a succession of instabilities that create flows of increasing temporal and spatial complexity (Lord Rayleigh, Sommerfeld, Heisenberg, Taylor, Landau etc), For the classroom example of pipe flow and several other flows, the linear stability analysis of the laminar profile does not reveal any instability, so that the very first point in that cascade of instabilities is absent. Over the last decade much of the mystery of the transition in pipe flow has been resolved, primarily thanks due to suitable adaptations and extensions of ideas from nonlinear dynamics. Numerical and experimental data corroborate a scenario where the appearance of new classes of fully 3d solutions and their increasing entanglement provides the key ingredients for the transition. Further studies on the spatio-temporal dynamics in the transition region, where turbulence is not space-filling, reveal intriguing similarities to the directed percolation transition in statistical mechanics.
    8 January 2026, 2:28 pm
  • 1 hour 10 minutes
    Gone with the wind: The demise of protoplanetary discs and the birth of planets
    Protoplanetary discs are natural consequence of star formation. These discs hold the left-over material from star formation, which constitutes the reservoir from which new planetary systems may form. The fate of a new planetary is then intimately linked to the evolution and final dispersal of the disk from which is born, which determines also the striking diversity observed in extra-solar planetary systems. I will briefly review our understanding of disc dispersal via a photoevaporative wind in the context of planet formation, and show how both processes are finally dominated by the irradiation from their central star.
    8 January 2026, 2:28 pm
  • 1 hour 21 minutes
    Understanding the LIGO gravitational wave event (GW150914)
    In February 2016 the LIGO team announced the detection of gravitational waves (GW) created by the merger of two black holes. In addition to confirming a major prediction of general relativity, successful GW detection would provide a powerful new tool for astrophysics. Given their evident importance, the LIGO results and the methods which led to them deserve independent critical analysis. This talk will present the results of one such study in a manner suitable for non-specialists.
    8 January 2026, 2:28 pm
  • 1 hour 9 minutes
    Arnold Sommerfeld Theory Colloquium
    The next generation of surveys, e.g. the Dark Energy Survey, PanSTARRS, LSST, Euclid and others, aim to study the nature of Dark Energy and alternatives. The talk will discuss how the Dark Energy paradigm evolved over the past 20 years, and the cosmic probes which will help us to test it. In particular the surveys rely on accurate of photometric redshifts for the determination of cosmological quantities such as Dark Energy parameters and neutrino masses. The talk will describe photometric redshift methods and their impact on analysing galaxy clustering and weak lensing data and on the derived cosmological parameters.
    8 January 2026, 2:28 pm
  • 1 hour 15 minutes
    Activating quantum matter
    In driven open quantum matter, coherent many-body quantum dynamics, drive, and dissipation play equally significant roles. These systems span a wide range of examples, including cold atomic gases, exciton-polaritons in solid state, and quantum devices designed for quantum information applications. These setups break the conditions of thermodynamic equilibrium on the microscopic scale, prompting questions about how this impacts macroscopic behavior, such as phases and phase transitions. We examine two key points: First, we showcase that a minor out-of-equilibrium perturbation on the microscopic level can lead to substantial macroscopic effects, including the emergence of novel non-equilibrium universality classes. This paves the way to active quantum matter scenarios in solid state physics. Second, we argue that drive and dissipation can be used constructively to maintain or even create fragile quantum mechanical correlations such as phase coherence, entanglement or topological order by carefully engineering the system. A topological quantum phase transition far from equilibrium can be induced in this way, exhibiting intriguing analogies to the problem of directed percolation.
    8 January 2026, 2:28 pm
  • 1 hour 20 minutes
    Ecology and Perpetual Evolution in High Dimensions
    In a simple, constant environment does evolution continue forever? Does extensive diversification via small genetic and ecological differences? What are general evolutionary consequences of organismic complexity? Hints from long term laboratory evolution experiments and findings from genomic data of extensive within-species bacterial diversity motivate considering these questions. Several simple models of evolution with ecological feedback will be introduced, with the high dimensionality of phenotype space enabling analysis by statistical physics approaches.
    8 January 2026, 2:28 pm
  • 1 hour 12 minutes
    Mystery of highest energy particles in the Universe
    Ultra-High-Energy Cosmic Rays (UHECRs) are particles with energies up to $3\times 10^20 eV$, originating from unknown sources and producing extensive air showers in Earth's atmosphere. In this talk, I will review the current status of UHECR observations, including the energy spectrum, mass composition, and anisotropy in their arrival directions. I will highlight how the knowledge of the Galactic Magnetic Field (GMF) of the Milky Way is crucial for identifying UHECR sources. Additionally, I will review recent models of the GMF. Finally, I will discuss the propagation of UHECRs from their sources through both intergalactic and galactic magnetic fields, and I will explore the prospects for future source identification.
    8 January 2026, 2:28 pm
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