Liste der Beiträge

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  1. 28/02/2026, 15:00
  2. Prof. Tim Dietrich (University of Potsdam)
    01/03/2026, 09:00

    Describing the most compact objects in the Universe requires the use of Einstein's general relativity and solving its field equations. In the presence of matter, these equations must at least be coupled with the equations of general-relativistic hydrodynamics, and the potential inclusion of magnetic fields or neutrino radiation further increases the complexity.
    While analytic solutions exist...

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  3. Andreas Schmitt
    01/03/2026, 10:00

    Ultra-dense matter in neutron stars is governed by the theory of the strong nuclear force, QCD. After a brief introduction to QCD and its phase diagram I will discuss the basic properties of dense nuclear and quark matter. I will then focus on the color-superconducting phases of quark matter, where quarks form Cooper pairs just like electrons in an ordinary superconductor. The lectures will be...

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  4. Mr Henrik Rose (Institut für Physik und Astronomie, Universität Potsdam)
    01/03/2026, 11:30

    Evaluating joint models for the electromagnetic and gravitational signals received from the 2017 neutron-star merger has proven both challenging and insightful. By incorporating further model assumptions or different data sources, we can obtain even tighter constraints on related fields. In particular, such mergers offer a natural connection to both nuclear properties through the dense-matter...

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  5. Pinaki Roy (University of Waraw)
    01/03/2026, 11:45

    The Hubble constant is a crucial cosmological parameter that is a measure of the rate of change of the cosmic scale factor per unit cosmic scale factor i.e. a_dot / a. There is a considerable discrepancy between the measurements of the Hubble constant from standard candle observations and those from cosmic microwave background (CMB) observations. Data from gravitational wave (GW) events can...

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  6. David Alvarez-Castillo (Institute of Nuclear Physics PAS)
    01/03/2026, 12:00

    In this presentation I briefly discuss the role of the symmetry energy on low mass twin compact stars under the framework of the state-of-the-art compact star measurements. In particular, I review the conjecture of the universal symmetry energy contribution to the compact star equation of state that follows from the direct Urca constraint for the cooling of low mass compact stars. Implications...

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  7. Valéria Carvalho
    01/03/2026, 12:15

    The equation of state (EoS) of neutron star matter encodes the relationship between pressure and density at supranuclear densities, fundamentally governing the star’s structure and observable macroscopic properties, such as mass, radius, and tidal deformability. In this work, we apply Neural Posterior Estimation (NPE) with conditional normalising flows to infer the EoS from synthetic...

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  8. Levon Pogosian
    01/03/2026, 14:00

    The Lambda Cold Dark Matter (LCDM) model has been remarkably successful in describing a wide range of cosmological observations, in particular the very precisely measured anisotropies of the cosmic microwave background (CMB) temperature and polarization. In recent years, other types of cosmological data have reached levels of accuracy that allow them to constrain certain LCDM parameters with...

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  9. Prof. Tim Dietrich (University of Potsdam)
    01/03/2026, 15:00

    Exercises for the lectures of Prof. T. Dietrich.

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  10. Theau DIVERRES (GANIL)
    01/03/2026, 16:30

    The crust of a neutron star is important for many astrophysical phenomena such as the cooling of the star and its transport properties. I will discuss results for neutron-star-crust elastic properties, namely the shear modulus, and their associated uncertainties, obtained within a bayesian analysis.

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  11. mahboubeh shahrbaf motlagh
    01/03/2026, 16:45

    We investigate the equation of state (EOS) and macroscopic properties of neutron stars (NSs) and hyperonic stars within an Ab initio approach extended to include interacting Λ hyperons. The ΛN and ΛΛ interactions are described by realistic spin- and parity-dependent potentials fitted to hypernuclear data. Cold, charge-neutral, and β-equilibrated matter composed of neutrons, protons, electrons,...

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  12. Mr Stefanos Tsiopelas (University of Wrocław)
    01/03/2026, 17:00

    The equation of state (EoS) for dense, strongly interacting matter serves as the central input in astrophysical simulations involving isolated compact objects and binary systems across various scenarios. While numerous models exist to describe the composition of cold neutron stars, the range narrows considerably when considering EoS that encompass varying temperatures, densities, and electron...

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  13. Mr Rafael Cardoso (Federal University of Santa Catarina and University of Coimbra)
    01/03/2026, 17:15

    The quark anomalous magnetic moment (AMM) of quarks is generated by a dynamical chiral symmetry breaking for massive quarks. In this way, the recent literature has applied the quark AMM on the magnetized Quantum Chromodynamics (QCD) phase diagram in order to predict different physical phenomena. In particular, the effect of the inverse magnetic catalysis, i.e., the decrease of the quark...

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  14. Tim Dietriech
    02/03/2026, 09:00

    Describing the most compact objects in the Universe requires the use of Einstein's general relativity and solving its field equations. In the presence of matter, these equations must at least be coupled with the equations of general-relativistic hydrodynamics, and the potential inclusion of magnetic fields or neutrino radiation further increases the complexity.
    While analytic solutions exist...

    Go to contribution page
  15. Andreas Schmitt
    02/03/2026, 10:00

    Ultra-dense matter in neutron stars is governed by the theory of the strong nuclear force, QCD. After a brief introduction to QCD and its phase diagram I will discuss the basic properties of dense nuclear and quark matter. I will then focus on the color-superconducting phases of quark matter, where quarks form Cooper pairs just like electrons in an ordinary superconductor. The lectures will be...

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  16. Ishfaq Ahmad Rather (ITP, Goethe University)
    02/03/2026, 11:30

    Gravitational wave astronomy provides a vital tool for probing extreme matter. This study investigates $f$-mode oscillations of cold, catalyzed Neutron stars as well as protoneutron stars with different evolutionary phases. We analyze the collective impact of nucleons, hyperons, phase transition to the quark matter, and dark matter admixtures on these oscillations employing full General...

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  17. Mr Pavlo Panasiuk (University of Coimbra)
    02/03/2026, 11:45

    In contrast to symmetric nuclear matter, which has been extensively studied in laboratory experiments, the matter inside neutron stars is highly isospin-asymmetric. We investigate the properties of strongly interacting matter under both symmetric and neutron-star-like conditions to determine how electric charge neutrality and beta equilibrium influence the emergence of quark matter. In...

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  18. Ms Streeta Roy (University of Warsaw)
    02/03/2026, 12:00

    Gravitational waves have proven to be an excellent tool for
    understanding populations of binaries. For the upcoming LISA detector,
    Binary White Dwarfs are one of the most promising sources. In this work,
    we focus on modelling the Gravitational wave background from White Dwarf
    Binaries in the LISA sensitivity range and building a model of their
    population in the Milky Way.
    The COMPAS...

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  19. Sarah Louisa Pitz (Goethe University Frankfurt am Main)
    02/03/2026, 12:15

    We investigate the impact of a stiff dark matter equation of state (EoS) on the structure and stability of neutron stars. For dark matter, we use bosonic, self-interacting scalar fields that generate ultra-compact boson stars with compactness exceeding 1/3. Varying the dark matter particle mass and stiffness shifts stellar configurations across distinct regions of the mass–radius diagram,...

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  20. Levon Pogosian
    02/03/2026, 14:00

    The Lambda Cold Dark Matter (LCDM) model has been remarkably successful in describing a wide range of cosmological observations, in particular the very precisely measured anisotropies of the cosmic microwave background (CMB) temperature and polarization. In recent years, other types of cosmological data have reached levels of accuracy that allow them to constrain certain LCDM parameters with...

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  21. Andreas Schmitt
    02/03/2026, 15:00

    Exercises for the Lectures of Prof. A. Schmitt.

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  22. Levon Pogosian
    02/03/2026, 16:30
  23. Hosein Gholami
    02/03/2026, 17:30

    Recent observations of neutron stars provide insights into the equation of state of matter at high densities, where exotic phases may emerge. One candidate is color superconductivity, in which quarks form diquark pairs that condense. A first-principles understanding of diquark dynamics is therefore essential for interpreting astrophysical data. In this work, we present a self-consistent,...

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  24. Melissa Mendes (TU Darmstadt)
    02/03/2026, 17:45

    The nuclear matter equation of state (EOS) is poorly known at the limit of high density and temperature. While this limit is not currently reached in laboratory settings, it is in neutron star interiors. In this talk, I will discuss an approach to probing the EOS using neutron star measurements. I will describe how neutron star mass and radius inferences from the NICER telescope and tidal...

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  25. Mark Alford
    03/03/2026, 09:00

    Bulk viscosity in nuclear matter. In a neutron star merger, nuclear matter experiences dramatic changes in temperature and density that happen in milliseconds. Mergers therefore probe dynamical properties that may help us uncover the phase structure of ultra-dense matter. I will describe some of the relevant material properties, focusing on flavor equilibration and its consequences such as...

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  26. Dominik Schwarz
    03/03/2026, 10:00

    Physical cosmology is relying on a rich spectrum of observational and experimental methods to probe the Universe. The new aspect is that for more and more cosmological questions, different complementary messengers and probes become available. This allows us to move from a picture of cosmic complementarity to cosmic consistency. In the first lecture I will approach modern observational...

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  27. Sagnik Chatterjee (IFIN-HH)
    03/03/2026, 11:30

    The neo-neutron star (neo-NS) phase directly follows the proto-neutron star (PNS) phase. During the PNS phase, the core of the star forms and acquires its final properties, such as composition and size, whereas the crust forms later during the neo-NS phase. This work is a further development of previous neo-NS studies carried out by one of the authors.
    I will present our preliminary results...

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  28. Pratul Manna (Astronomical Observatory, University of Warsaw)
    03/03/2026, 11:45

    One of the key factors influencing the structure and evolution of neutron stars is differential rotation. It plays a crucial role in understanding the behavior of matter in extreme conditions and affects observable properties like gravitational wave signals from Core-collapse supernovae or binary merger events. However, a major uncertainty exists surrounding the equation of state (EoS) used...

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  29. Dr Mikhail Beznogov (National Institute for R&D in Physics and Nuclear Engineering (IFIN))
    03/03/2026, 12:00

    A significant fraction of neutron stars (NSs) rotate, and they can rotate very fast (e.g., millisecond pulsar). An isolated rotating NS or an NS that has permanently stopped accreting from its companion gradually loses its rotational energy and spins down. The most common cause for this is magnetic braking. As the star spins down, the centrifugal force decreases, the star shrinks, and its...

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  30. Henrik Danielyan (Yerevan State University)
    03/03/2026, 12:15

    We compute the thermal conductivity and thermoelectric power
    (thermopower) of the inner crust of compact stars across a broad
    temperature–density domain relevant for proto–neutron stars, binary
    neutron-star mergers, and accreting neutron stars. The analysis
    covers the transition from a semi-degenerate to a highly degenerate
    electron gas and assumes temperatures above the melting...

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  31. Dominik Schwarz
    03/03/2026, 14:00

    Physical cosmology is relying on a rich spectrum of observational and experimental methods to probe the Universe. The new aspect is that for more and more cosmological questions, different complementary messengers and probes become available. This allows us to move from a picture of cosmic complementarity to cosmic consistency. In the second lecture, I plan to present the example of...

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  32. Mark Alford
    03/03/2026, 15:00

    Exercises for the talks of Prof. M. Alford.

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  33. Tigran Petrosyan (Yerevan State University)
    03/03/2026, 16:30

    We study the influence of positrons on the outer crusts of neutron
    stars and the interiors of white dwarfs, introducing them as a novel
    component in both the composition of matter and in transport
    processes. We solve a system of coupled Boltzmann kinetic equations
    for the electron and positron distribution functions in the
    relaxation-time approximation, taking into account...

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  34. Kruthi Krishna (DESY Zeuthen, UPotsdam and DZA)
    03/03/2026, 16:45

    Identifying the electromagnetic counterparts to gravitational wave sources is vital to enabling the myriad of investigations possible with multi-messenger astronomy. However, locating faint, fast-varying transients in large sky localisations, given the intrinsic uncertainty in their detailed properties, is challenging. Here we investigate the expected gravitational wave localisations for a...

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  35. Dr Alexander Ayriyan (University of Wroclaw)
    03/03/2026, 17:00

    We study the equation of state of neutron star matter using Bayesian inference based on multi-messenger observations, including pulsar mass measurements, NICER mass-radius constraints, and tidal deformability inferred from the gravitational-wave event GW170817. Hybrid equations of state are constructed by combining hadronic matter models with quark matter described by a nonlocal NJL model with...

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  36. Dominik Schwarz
    04/03/2026, 09:00
  37. Mark Alford
    04/03/2026, 10:00

    Solid quark matter. I will review three ways in which quark matter can occur in a solid phase, where translational invariance is broken by some sort of crystalline structure. These include a color superconductor of the Fulde-Ferrell-Larkin-Ovchinnikov type, mixed phases that can arise at a nuclear/quark matter interface, and the strangelet crystal crust of a strange star.

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  38. Christoph Gärtlein (University of Lisbon, University of Wroclaw, University of Coimbra)
    04/03/2026, 11:30

    We explore the role of color superconductivity in quarkyonic matter under the conditions of color and electric neutrality at $\beta$- and strong equilibrium, as relevant for neutron stars. By explicitly incorporating the color-superconducting pairing gap into the phenomenological model of a smooth transition from hadron to quark matter, we extend the known quarkyonic framework to include this...

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  39. Harutyun Gabuzyan (Yerevan State University)
    04/03/2026, 11:45

    The hot quark matter created in heavy-ion collision experiments can
    exhibit strong temperature and chemical-potential gradients, which in turn can generate electric fields through thermoelectric
    effects. In this work, we investigate two relevant thermoelectric
    coefficients—the thermopower (Seebeck coefficient) and the Thomson
    coefficient—of two-flavor quark matter using the Kubo...

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  40. Mr Maël Gonin
    04/03/2026, 12:00

    Gravitational wave detection has revived primordial black holes (PBHs) as a compelling dark matter candidate. PBH formation from overdensity collapse during the radiation-dominated era depends sensitively on the cosmic equation of state, particularly across the QCD transition. Following Bödeker et al. 2021, I investigate how lepton flavor asymmetries—poorly constrained prior to neutrino...

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  41. Ms Selina Kunkel (Goethe University Frankfurt)
    04/03/2026, 12:15

    At high densities and low temperatures, hadronic matter is expected to undergo a first-order phase transition into a color-superconducting state. While such conditions occur in neutron stars, studies focusing only on cold neutron stars are not fully conclusive because they neglect the evolutionary processes that may influence the appearance of color-superconducting phases. A proto–neutron...

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  42. Veronica Dexheimer
    04/03/2026, 14:00

    Matter inside neutron stars and their mergers can reach densities of more than 10 times normal nuclear density. In such extreme environments, new particles and phases of matter appear, as well as different interactions become important. In my lectures, I review old and new ways to use neutron star observables to learn about dense matter, comment on what we know and what we expect to discover...

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  43. Veronica Dexheimer
    04/03/2026, 15:00
  44. Mr Ioannis Liodis (Deutsches Elektronen-Synchrotron (DESY))
    04/03/2026, 16:30

    The measurement of the Hubble constant has became a critical effort given the discrepancy between the early and late universe measurements, dubbed as the Hubble tension. Since the discovery of gravitational waves (GWs) in 2015, compact binary mergers are used as an independent probe to infer cosmological parameters, since they may allow for joint measurements of their luminosity distance and...

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  45. Ms Sakshi Maurya (Astronomical Observatory, University of Warsaw)
    04/03/2026, 16:45

    Active galactic nuclei (AGNs) are among the most energetic objects in the Universe, with relativistic jets launched by accreting supermassive black holes. Blazars, a subclass of AGNs with jets aligned close to our line of sight, often exhibit strong variability across the electromagnetic spectrum. Quasi-periodic oscillations (QPOs) in blazar light curves can provide important clues about the...

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  46. Prof. David Blaschke (University of Wroclaw)
    04/03/2026, 17:00
  47. Günther Hasinger
    04/03/2026, 17:30
  48. Samaya Nissanke
    05/03/2026, 09:00
  49. Veronica Dexheimer
    05/03/2026, 10:00

    Matter inside neutron stars and their mergers can reach densities of more than 10 times normal nuclear density. In such extreme environments, new particles and phases of matter appear, as well as different interactions become important. In my lectures, I review old and new ways to use neutron star observables to learn about dense matter, comment on what we know and what we expect to discover...

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  50. Dr Massine El Kabir (Sapienza University of Rome)
    05/03/2026, 11:30

    Identifying electromagnetic counterparts to neutron star mergers (Kilonovae) is crucial for multi-messenger astronomy but is made difficult by the presence of contaminants. In this work, we present an analysis of AT2025ulz: an optical candidate identified within the localization of the gravitational wave event S250818k. Despite initial spatio-temporal consistency, deep Hubble Space Telescope...

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  51. Anirudh Nemmani (Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences (CAMK PAN))
    05/03/2026, 11:45

    Compact binary black hole systems are a primary source of gravitational wave detection through LIGO-Virgo-KAGRA detectors. Recent improvements to the detectors have led to improved sensitivity, leading to the detection of more gravitational wave signals. Recent studies have suggested the possibility of observing binary systems in the sub-solar mass range. In third-generation detectors, the...

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  52. Dr Niccolo' Passaleva (Sapienza University of Rome)
    05/03/2026, 12:00

    The merging of binary black hole (BBH) systems produces gravitational wave (GW) events. We can use their direct measurement of luminosity distance (dL) in combination with the redshift of the merging system to place cosmological constraints. BBH mergers are not expected to produce any electromagnetic counterpart; thus, to obtain the redshift of the source event, we rely on a statistical...

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  53. Mr Davood Rafiei Karkevandi (University of Wroclaw, Institute of Theoretical Physics)
    05/03/2026, 12:15

    Neutron stars provide a unique laboratory to probe dark matter (DM) through its gravitational imprint on stellar evolution. We study proto-neutron stars in a two-fluid, quasi-static framework with non-annihilating asymmetric DM (fermionic or bosonic) that interacts with ordinary matter only via gravity, and follow the Kelvin–Helmholtz cooling phase. We find a clear thermal signature: compact...

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  54. Samaya Nissanke
    05/03/2026, 17:00
  55. Samaya Nissanke
    05/03/2026, 18:00
  56. 06/03/2026, 09:30