Upcoming Seminars & Tutorials

Dark matter ‘lighting up’ the neutron star

  • Dr. Deep Ghosh
  • 05 August 2026, 03:00 PM
  • PAMU Seminar Room

Neutron star (NS) being rich in baryons can act as a natural laboratory to test dark matter (DM)-baryon interactions with the advent of new telescopes like JWST as well as gravitational waves detector facility at LVK collaboration. In this talk, I shall discuss how astrophysical evidences indicate dark matter intervention in resolving mysteries regarding NSs. In particular, I shall show bosonic DM capture in NSs has a rich phenomenology in deciding various NS observables. If bosonic DM forms condensate and annihilates inside the NS, old neutron stars glow brighter than usual, in turn, become detectable by the JWST. On the other hand, if DM is non-annihilating, the gravitational collapse of the dark core can initiate transmutation of a neutron star into a solar mass black hole, which warrants dedicated GW searches at LVK facility. All these phenomena can be realized in a realistic DM model, especially in freeze-in DM scenarios.

Synchronization and Pattern Formation in Directed Higher-Order Structures

  • Mr. Wilfried Segnou Tchio Kuété
  • 05 August 2026, 12:00 PM
  • PAMU Seminar Room

Many complex systems cannot be adequately described through pairwise interactions alone. In biological, social, and technological systems, collective dynamics often emerge from interactions involving several units simultaneously. Accounting for these higher-order interactions is therefore essential for understanding phenomena that conventional network models may fail to capture, including synchronization, pattern formation, and dynamical instabilities.

Hypergraphs provide a natural framework for representing such interactions by allowing a single connection—a hyperedge—to involve multiple nodes. Directed hypergraphs further encode asymmetric influence among groups of nodes. In particular, (m)-directed hypergraphs make it possible to distinguish the source and target groups participating in an interaction and thus offer a flexible mathematical representation for investigating nonlinear dynamics on directed higher-order structures.

A theoretical framework for coupled nonlinear dynamical systems defined on (m)-directed hypergraphs is introduced. Its applicability is illustrated through two paradigmatic collective phenomena. First, diffusion-driven instabilities and the emergence of Turing patterns are examined, emphasizing how directionality and higher-order topology affect the onset and spatial organization of these patterns. Second, the synchronization of Stuart–Landau oscillators is investigated, highlighting how directed higher-order interactions influence the existence and stability of coherent states. These results underscore the key role played by the interplay between nonlinear dynamics, interaction order, and structural directionality in shaping collective behavior.