The Sixth Zeldovich meeting

Session

Gravity and cosmology

17 Jul 2026, 15:00

ICRANet, Pescara, Italy

Conveners

Gravity and cosmology

• Manuel Hohmann (University of Tartu)

63. On the formation of compact-object binaries from binary-driven hypernovae

Dr Laura Marcela Becerra Bayona (Universidad Industrial de santander)

17/07/2026, 15:00

Invited talk

I will present smoothed-particle hydrodynamics (SPH) simulations of the binary-driven hypernova (BdHN) scenario for long gamma-ray bursts (GRBs), focusing on the stability of the binary system during the supernova (SN) explosion. The progenitor of a BdHN consists of a carbon–oxygen (CO) star and a neutron-star (NS) companion. The core collapse of the CO star triggers an SN explosion and forms...

52. Extreme Kerr-Newman Black Holes: Differential Geometry, Symmetry, and the Golden Ratio

Prof. Giorgio SONNINO (International SOLVAY Institutes for Physics and Chemistry & Université Libre de Bruxelles (U.L.B.))

17/07/2026, 15:35

Invited talk

Using the Christodoulou-Ruffini and Hawking mass-energy relations as a starting point, we investigate the properties of extreme black holes from a differential-geometry perspective. The geometry of black-hole horizons is of fundamental importance, as it offers deep insight into the structure of spacetime and the behavior of gravitating systems in the strong-field regime. We present two...

8. Non-Keplerian Galaxy Rotation Curves as a Testing Ground for Precanonical Quantum Gravity

Dr Igor Kanatchikov (Natl. Quantum Information Center in Gdansk)

17/07/2026, 16:10

Oral presentation

We show that a variety of non-Keplerian galaxy rotation curves, together with the corresponding modifications of the Newtonian potential and dynamics, including MOND, qMOND, and mMOND-type behaviors, can be derived for test particles propagating on a background quantum geometry associated with a quantum spin connection, as described by precanonical quantum gravity (pQG).

In particular, we...

36. Evolution of Virial Clouds -- II: From the formation of first stars up to their explosion

Noraiz Tahir (Department of Physics and Astronomy, School of Natural Sciences (SNS), National University of Science and Technology (NUST), H12, Islamabad, Pakistan)

17/07/2026, 16:45

Oral presentation

It had been proposed [Qadir A., Tahir N., and Sakhi M., PRD 100, (2019)] that virial clouds “propped up” by the cosmic microwave background (CMB), and hence at that temperature, populate dark matter halos and may account for a significant fraction of the missing baryons. To understand the nature of these clouds, it is necessary to trace their evolution from the last scattering surface (LSS)...

45. Neutrino Mixing in Torsionful Spacetimes: Quantum-Gravity Signatures and Dark-Universe Implications

Simone Monda (Università degli Studi di Salerno)

17/07/2026, 17:00

Oral presentation

Spacetime torsion provides a natural bridge between spin, gravity and quantum fields, and may leave observable imprints in fermionic sectors relevant to cosmology. I will discuss recent results on neutrino mixing in torsionful spacetimes within a quantum-field-theoretical framework, focusing on the phenomenological aspects most directly connected with relativistic astrophysics, quantum gravity...

16. Towards an Action Principle Unifying the Standard Model and Gravity

Fernando Izaurieta (Universidad San Sebastián)

17/07/2026, 17:15

Oral presentation

A single geometric invariant fixes the relative normalization and structure of gravity, Yang-Mills theory, and fermion kinetic terms, including ghost freedom in the gravitational sector, without tuning. Our results establish a minimal geometric route to unification that does not rely on extra dimensions or symmetry breaking by hand. Unlike previous gauge-gravity constructions, the relative...

39. Addressing the Hubble tension with a dynamical Λ(z) induced by galactic gravitational self-energy and by backreaction force from gas cloud collapse

Stephan Walrand (université catholique de Louvain)

17/07/2026, 17:30

Oral presentation

In a recent publication, we derived a general relativity (RG) gauge-invariant solution modelling a granular universe composed of spherical bodies with a radial Gaussian density profile. In this framework, a cosmological constant Λ emerges natively from the gravitational self-energy of these discrete nodes. Energy conservation dictates a uniform compactness ratio M/σ^2 across all bodies, a...

76. Concluding remarks

Remo Ruffini (ICRANet, ICRA, INAF)

17/07/2026, 17:40

47. Relativistic Dark Matter spikes around supermassive Black Holes: Morphologies and constraints in the fermionic RAR model.

Valentina Crespi (Instituto de Astrofísica de La Plata)

Invited talk

Over the last decades, it has been established that dark matter (DM) rearranges around compact objects, forming over-densities known as spikes. We focus on the framework based on the Ruffini-Argüelles-Rueda (RAR) model, where the quantum nature of keV-fermions leads to a distinct core-halo morphology. In this context, we address the scenario where a central Supermassive Black Hole (SMBH)...