GeomGravX: 10 Years of Geometric Foundations of Gravity and eXtensions (in Tartu)

Contribution List

63. 3+1 decomposition and Hamiltonian analyses in symmetric teleparallel theories

Dario Sauro (Theoretical Physics Institute University ofJena)

Oral or Poster

We perform a 3+1 decomposition in a general symmetric metric-affine theory, classifying the extrinsic tensors and deriving the generalized Gauss-Codazzi relations. The latter are exploited to perform the teleparallel limit in a model-independent fashion, thus identifying the extrinsic non-metricity tensor which plays the role of the extrinsic Riemannian curvature. We further prove that no...

10. A Geometric Interpretation on Gravity and Acceleration Scale

Dr Bilgehan Baris ONER

Poster

Mach’s principle can be implemented in general relativity by introducing a vector field, which we call the geometric drift vector, within the framework of teleparallel gravity and the tetrad formalism. We investigate the physical viability of the drift field, the Lorentz covariance of the theory, its limiting cases, and its consistency with current cosmological observations. The model provides...

15. A GUP-inspired quantum black hole: the static and rotating cases, and their phenomenology

Prof. Saeed Rastgoo (University of Alberta)

Oral talk

I present a new model of a black hole derived systematically from deforming the canonical algebra inspired by the generalized uncertainty principle (GUP). This model has two quantum parameters controlling the onset and strength of quantum gravity effects. I will discuss the geometry of both the static case and the rotating model derived using Newman-Janis algorithm. Furthermore, I show how a...

50. A practical guide to unifying the Khronon

Priidik Gallagher (University of Tartu)

Oral talk

A review of the question how to put the Cartan Khronon into a gauge-gravity unified field theory is provided. The issues are several-fold, from conceptual to technical: suggestions for future developments are provided. The Cartan Khronon is quite special in its particular balance of self-dual Einstein-Cartan gravity constrained to waywiser form, thus producing ideal dust. However, supplying...

28. A simple example of “non-minimal” Pre-Big Bang scenario

Pietro Conzinu (Scuola Superiore Meridionale)

Oral or Poster

We give an example of non-minimal pre-big bang scenario able to produce the PTA signal
considering a modified evolution of the high-curvature string phase, including the contribution of high-
energy string sources. We use a fluid-dynamic model of sources and show that their effective viscosity
breaks the S-duality symmetry of the tensor-axion perturbation spectra, as in general expected...

23. A Variational Framework for Linearised Theories

Pietro Isaia (Università di Torino)

Oral or Poster

The usual approach to perturbation theory presents some mathematical flaws. For instance, when studying gravitational waves (GW) around a Minkwoski background, one usually imposes the weak-field limit, requiring the spacetime metric to be the Minkowski metric plus a small perturbation. However, the bundle of Lorentzian metrics is neither linear nor affine; thus, the addition operation is not...

26. Bianchi cosmology (in 1-parameter NGR)

Paul Martin Kull (University of Tartu)

Oral or Poster

Our current understanding of the Universe is that it is isotropic, which means that spherically symmetric models of spacetime are the preferred choice for any geometrical considerations about the Universe. However, some observations point to an asymmetry in the CMB, the "axis of evil," that could be explained by a non-isotropic Universe. This can potentially be leveraged to help solve another...

11. Black Hole Interior Structure Under Nonlinear Torsion-Scalar Effects

Dr Bilgehan Baris ONER, Mr Melih GUMUS

Poster

Black hole singularities continue to pose a major topic in almost all gravitational theories. Here we propose a geometric picture for regular (non-singular) black hole interiors in teleparallel gravity, formulated in terms of geometric drift vectors. In a comoving tetrad setup, gravity is described by an evolving drift field whose spatial variations give rise to torsion instead of curvature....

39. Canonical and non-canonical symmetries in f(R) cosmology

Francesca Spinnato (Scuola Superiore Meridionale)

Oral talk

The f(R)-gravity represents the most straightforward extension of the General Relativity. Among the different possible formulations, the starting action can be selected using the Noether symmetry approach, a phisically motivated criterion based on Noether's theorem aimed at identifying viable models that exhibit symmetries. An advantage in applying such an approach is the reduction of the...

31. Charged asymptotically flat and asymptotically (A)dS black holes in quadratic gravity

Vojtech Pravda (Institute of Mathematics of the Czech Academy of Sciences)

Oral talk

We study static, spherically symmetric, asymptotically flat and asymptotically (A)dS charged black holes in quadratic gravity. Using the conformal-to-Kundt method, we simplify the field equations and derive the solutions in the form of a power series with coefficients determined by a recurrent formula. In addition to charge and mass, these black holes possess one additional parameter – the...

46. Clustered unified dark sector cosmology

Mahmoud Hashim (Centre for Theoretical Physics, the British University in Egypt)

Oral talk

We consider unified dark sector models in which the fluid can collapse and cluster into halos, allowing for hierarchical structure formation to proceed as in standard cosmology. We show that both background evolution and linear perturbations tend toward those in Λ cold dark matter (ΛCDM) as the clustered fraction f→1. We confront such models with various observational datasets, with emphasis...

33. Conformal gauge gravity and linearized particle spectra

Joosep Lember (University of Tartu)

Oral or Poster

Shortcomings of GR motivate the study of extended theories of gravity, while other fundamental interactions, successfully formulated as gauge theories, drive the development of a gauge theory of gravity. We will present a gauge-theoretic framework of gravity based on spontaneous symmetry breaking of the conformal group to the Lorentz group. The geometry can be defined from a connection and two...

6. Cosmological Probes of Gravity Beyond General Relativity

David F. Mota

Oral talk

Several modifications to general relativity have been proposed to explain the nature of dark energy and the accelerated expansion of the Universe. In this talk, I will review the current status of modified theories of gravity, focusing on astrophysical probes in the nonlinear regime. I will begin by outlining the expected behavior of theories beyond General Relativity in various astrophysical...

47. Cosmology and Inflation with Torsion and Nonmetricity

Ilaria Andrei (University of Tartu)

Oral talk

Metric affine gravity (MAG) represents an extension of general relativity (GR) in which the metric and affine connection are independent geometrical variables. This leads to two, in addition to curvature, tensors describing the geometry of spacetime, torsion and nonmetricity. And a new tensor describing its matter content together with the stress energy tensor, the hypermomentum tensor. I will...

7. Dirac Fields in Hydrodynamic Form and their Gravitation

Sante Carloni (Università di Genova)

Oral talk

We reformulate spinor theory in a specific form, called ‘polar form,’ which relies solely on real variables, is independent of the particular representation of gamma matrices, and is manifestly covariant. In this form, the spinor field can be associated with a (fluid) continuum, and the corresponding Dirac theory can be reinterpreted as a type of hydrodynamics. We found that this effective...

32. Discrete 4D geometry from integer arithmetic: Hurwitz quaternions, gauge symmetries, and two compatible metric signatures

Petri Muinonen (Independent researcher)

Poster

We present a non-perturbative framework in which two compatible 4D spatial geometries emerge from sheer arithmetic properties of growing set of positive integers. The process of adding integers conceived as time, Lagrange's four-square theorem provides the dimensional foundation. Integer distances between integers in a ring algebra admit decomposition into four coordinates, with multiple...

41. Discrete Emergent Gravity: One Postulate, Zero Free Parameters

Mr Matteo Pinna

1

Poster

The Discrete Emergent Gravity (DEG) framework derives macroscopic physics from a single postulate: spacetime consists of N Planck-scale atoms, each carrying g = 442 internal quantum states from an SU(21)×U(1) gauge structure, governed by H = 0. No parameters are fitted to observation at any stage.

Two results are highlighted. The observed cosmological constant Λ = (1.088 ± 0.030) × 10⁻⁵²...

56. Dissipative Phenomena in Scalar-Tensor Inflation

Adrián Casado-Turrión (Center for Physical Sciences and Technology (FTMC))

Oral or Poster

Physical processes (including field interactions and cosmological evolution) might have different interpretations in different conformal frames. In this talk, we shall discuss how to consistently transform dissipative phenomena between distinct conformal-frame representations of scalar-tensor gravity, and explore the observable consequences thereof in warm inflation scenarios, where the...

48. Dynamical Dark Energy or Modified Gravity? Signatures in Gravitational Wave Propagation

Purnendu Karmakar (University of Tartu)

Oral or Poster

We discuss the implications of the most recent DESI Baryon Acoustic Oscillations (BAO) DR2 and DESyr5 compilation of supernovae (SNe) datasets for modified gravity, focusing on non-metricity-based f(Q) theory, by employing a ‘model-independent’ approach. We reconstruct dark energy density, which is then extended to estimate the perturbation-level quantities, sourced by the modified gravity,...

61. Emulator-Assisted Investigation of Left-Right Symmetric Higgs Inflation

Ms Mehraveh Nikjoo (University of Gdansk)

Oral or Poster

This work investigates inflation in a left-right symmetric extension of Higgs inflation, formulated in a first-order gravitational framework. Specializing to a single-field inflationary trajectory, the model admits two physically distinct cases: real $\bar{\gamma}$, associated with complex-conjugate non-minimal couplings, and purely imaginary $\bar{\gamma}=i\gamma_I$, associated with real...

59. Event horizon termination and the emergence of Lorentz signature

Dr Justin Feng (CEICO, FZU - Institute of Physics of the Czech Academy of Sciences)

Oral or Poster

In this talk, I describe in detail how one might understand the termination of the event horizon of a black hole in terms of of quasiregular singularity characterized by points possessing two future-directed light cones and two past-directed light cones (in fact this spacetime is conformal to a region of the 1+1 trousers spacetime). I then discuss Euclidean signature shift-symmetric...

35. Evolution of superhorizon perturbations in early Universe with anisotropic solid remnant

Daniel Račko

Oral or Poster

In this talk, I will discuss how a small anisotropic “solid remnant” left over after inflation could affect the early Universe. This model is inspired by solid inflation and its generalizations, in which matter is described by a triplet of fields. In our model, the full internal global Euclidean symmetry of this triplet is broken, leading to anisotropic expansion of the Universe. Superhorizon...

67. Exploring the Dynamics of Hairy Black Holes with Numerical Relativity

Miguel Zilhão

Oral or Poster

We report on the numerical evolutions of black holes with synchronized or resonant hair. We show that in the "very hairy" regime, the horizon gets naturally ejected from the center of its environment. This dynamical splitting is likely to be generic for sufficiently hairy BHs in the broader class of models with synchronized or resonant hair, but possible exceptions may exist.

51. Geometric Foundations in and beyond Gravity—The Perspective of Particle Detector Models

Sebastian Schuster (Stockholm University)

Oral talk

Already in general relativity, much of the most interesting physics has to do with semi-classical extensions and their physical effects. Early on, foundational issues were addressed through the introduction of the Unruh–DeWitt detect model which allowed an operational notion of particle detection. This described the then-recently discovered, semi-classical effects—like the Unruh effect and...

42. Geometric foundations of gravity and eXtended geometry

Daniel Blixt (Chalmers University of Technology)

Poster

General relativity is conventionally described by the Einstein-Hilbert action in terms of the curvature of the Levi-Civita connection. However, this formulation does not come without foundational issues. It needs to be supplemented by boundary terms in order for it to have a well-defined variational principle as well as finite sensible derivations of quantities such as mass. Boundary terms can...

3. Global portraits of inflation

Dr Laur Järv (University of Tartu)

Poster

In the phase space perspective, scalar field slow roll inflation is described by a heteroclinic orbit from a saddle type fixed point to a final attractive point. In many models the saddle point resides in the scalar field asymptotics, and thus for a comprehensive view of the dynamics a global phase portrait is necessary. For this task, in the literature one mostly encounters dynamical...

43. Gravitational Instantons and Chiral Reduction in Spin(4) Gauge theory of space-time.

Stylianos Papadopoulos (University of Tartu, Estonia)

Oral or Poster

\textbf{Abstract:\}
In this talk, the Spin(4) gauge formulation of spacetime with a Cartan khronon field is presented. As motivation, the relation between Euclidean and Lorentzian descriptions is recalled as a Wick-rotation prescription relating two dynamically equivalent descriptions of the same underlying field configurations, once a time direction is selected by the Cartan khronon. Within...

62. Gravitational Instantons in a Spin(4) Gauge Formulation of space-time.

Stylianos Papadopoulos (University of Tartu, Estonia)

Poster

Abstract

We present the Spin(4) gauge formulation of gravity based on a Cartan Khronon field, in which spacetime geometry is described through a gauge-theoretic framework and the coframe structure emerges from the covariant derivative of the Khronon field. The theory naturally decomposes into self-dual and anti-self-dual sectors associated with the Spin(4) connection, allowing for a chiral...

64. Imprints of the Large Magellanic Cloud on the Milky Way dark matter halo

Nassim Bozorgnia

Oral or Poster

The Large Magellanic Cloud (LMC) induces a significant time-dependent gravitational perturbation on the Milky Way dark matter halo, altering the local phase-space distribution of dark matter in the Solar neighborhood. Cosmological simulations that sample potential Milky Way formation histories provide a powerful framework to characterize the dynamical response of the halo to such a massive...

54. Lagrangian dynamics and Regge-like trajectories for microstructured test bodies

Damianos Iosifidis

Oral talk

I will introduce the Lagrangian formulation of microstructured test bodies containing all spin, dilation and shear charges and moving in a generalized non-Riemannian background. Using the equations of motion derived by this formulation I will study the evolution of the dynamical rest mass of the body. I will show that, due to the presence of non-metricity, the dynamical rest mass is no longer...

24. Locally Rotationally Symmetric Spacetimes in Einstein-Cartan Theory and Their Classification

Ujjwal Agarwal (Institute of Theoretical Physics, Charles University)

Oral talk

The complete set of covariant equations that govern the locally rotationally symmetric torsion spacetimes sourced by Weyssenhoff fluid in Einstein-Cartan-Sciama-Kibble gravity is presented. Using these equations, one can explore in detail the peculiar relationship between conformal structure and torsion. A comprehensive scheme to categorize these torsional spacetimes into distinct classes is...

13. Maxwellian gravity and the cosmological constant

Diego Molina (Universidad Arturo Prat)

Oral or Poster

Inspired by the power of algebraic expansions to reveal hidden structures in physical theories, we explore the role of infinite semigroup expansions in the context of gravitational theories, focusing on the derivation of Maxwellian gravity and its relation to the cosmological constant. By systematically extending the symmetry structure of AdS, we unveil a natural path leading from Poincaré...

52. More on the physical foundations of geometry

Tomi Koivisto (University of Tartu)

Oral talk

The series of breakthroughs witnessed at the previous conferences erupted last summer into a full-scale revolution. Presently the foundations of physics and of all sciences are shaken by a kaleidoscopic turmoil. This is a moment at which to revisit the main theme of the conference series.

Physics cannot rest on a geometrical foundation. The fact that geometrical descriptions are available...

60. Non-Relativistic Chern–Simons Supergravity with Torsion

Francisco Delgadillo (Universidad del Bio-Bio)

Oral or Poster

In this work, we construct a three-dimensional non-relativistic Chern–Simons supergravity theory with both curvature and torsion within the Mielke–Baekler framework. We show that a consistent non-relativistic supergravity formulation requires starting from a N = 2 supersymmetric extension of the Mielke–Baekler algebra and implementing a non-relativistic expansion via the semigroup expansion...

22. Non–Minimally Coupled Weyl Connection Gravity: Cosmological Perturbations

Margarida Lima (Instituto Superior Técnico)

Oral talk

In Non-Minimally Coupled Weyl Connection Gravity the spacetime geometry is not fully determined by the metric alone, but also involves the Weyl connection characterized by an independent non-metricity vector. As a result, the gravitational sector is enriched by a dynamical vector field, which contributes to the field equations and modifies the curvature terms. This model also introduces an...

19. Numerical relativity and hyperbolicity in teleparallel gravity

Maria Jose Guzman (University of Tartu, Estonia)

Oral talk

In this talk, I will present recent progress in the 3+1 formulation of the metric teleparallel and symmetric teleparallel equivalents of general relativity, TEGR and STEGR. For TEGR, I will discuss the linearized Hamilton's equations and their hyperbolicity properties. Although the original system of differential equations is not hyperbolic, we show that it can be recast as a strongly...

65. On the inverse problem of calculus of variations for autoparallels

Lehel Csillag (Transilvania University Brasov)

Oral or Poster

In metric–affine geometry, autoparallels are generically non-variational, i.e.\,, they are not the extremals of any action integral. The existence of a parametrization-invariant action principle for autoparallels is a long-standing open problem, which is equivalent to the so-called Finsler metrizability of the connection -- that is, to the fact that these autoparallels can be interpreted as...

55. One Lagrangian to rule them all

Fernando Izaurieta (Universidad San Sebastián)

Oral talk

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...

45. Oscillating images from dark matter scalar solitons

Caio Macedo

Oral talk

Real scalar fields, e.g. the axion, cannot condensate into stationary solitonic configurations to form starlike structures, eventually either dispersing or collapsing. However, by relaxing the stationarity condition on the metric, it has been shown that oscillatory solitonic solutions—known as oscillatons—exist. Oscillatons share several properties with boson stars, including comparable...

18. Polarimetric imprints of exotic compact objects

Hanna Liis Tamm (University of Tartu)

Oral talk

Recent observations of polarized light from galactic cores motivate the study of polarized exotic compact objects (ECOs), which can mimic the features of black holes (BHs) in the strong-field regime of gravity. In this work, the properties of three ultra-compact classes of models containing light rings are studied — relativistic thin-shell fluid spheres, thin-shell gravitational vacuum stars,...

8. Pre-metric gravity and gravitational metrological triangles

Claus Laemmerzahl (University of Bremen)

Oral talk

Usually the space-time metric of General Relativity is defined through electromagnetic phenomena, namely the speed of light. Here we propose a gravity-only approach in the sense of a pre-metric theory of gravity. It is now gravity itself which defines the space-time metric. Through this appoach it is possible to introduce a gravitational metrological triangle made of gravitational...

36. Primary constraints of newer general relativity

Carmen Ferrara (Scuola Superiore Meridionale)

Oral talk

We study the primary constraint structure of newer general relativity, a gravity theory based on a torsionless teleparallel geometry. The gravitational action consists of a scalar built from quadratic combinations of the nonmetricity tensor with arbitrary coefficients in the Lagrangian. We perform a 3+1 decomposition of the Lagrangian and compute the canonical momenta associated with the...

16. Primordial Black Holes as cosmic expansion accelerators

Dr Konstantinos Dialektopoulos (University of Malta)

Oral talk

In this seminar, I will present a novel mechanism for cosmic acceleration driven by primordial black holes with effective repulsive behavior. Using a new Swiss Cheese cosmological framework, I will discuss four black hole spacetimes—Hayward, Bardeen, Dymnikova, and de Sitter-Schwarzschild—to show that this acceleration emerges naturally from the geometry itself. The results suggest that...

66. Primordial Black Holes from Resonances in the Running-Mass-Inflation Model

Mindaugas Karciauskas (Center for Physical Sciences and Technology (FTMC))

Oral or Poster

Resonant excitations during inflation can amplify the primordial curvature perturbation within a narrow range of k values. This suggests a novel mechanism to generate Primordial Black Holes (PBHs). We study such resonances within the context of the Running-Mass-Inflation model. Generated PBHs can explain the totality of Dark Matter. The mechanism also predicts enhanced induced Gravitational...

20. Properties of generalized Schwarzschild spacetimes with extra dimensions

Peter Mészáros (Department of Theoretical Physics, Comenius University, Bratislava, Slovakia)

Oral talk

I will talk about static spacetimes that are spherically symmetric in three space dimensions, and have also n extra dimensions with Euclidean symmetry. I show that a specific ansatz leads to a limited set of vacuum solutions of the Einstein field equations, which can also be classified as Weyl solutions. I will talk about properties of these spacetimes investigated through the Kretschmann...

34. Renewed hope in new general relativity with boost violation

Daniel Blixt (Chalmers University of Technology)

Oral or Poster

Metric teleparallelism assumes both the curvature of the affine connection and non-metricity to vanish. Within this framework it is possible to construct an action which is quadratic in torsion and parity-preserving (known as new general relativity). For decades it was thought that only two subcases of this theories would be ghost-free. One being equivalent with general relativity, and the...

9. Scalarization of Reissner-Nordström Black Hole in Scalar-Torsion Teleparallel Gravity

Joaquín Robledo Montenegro (Universidad de La Serena)

Oral talk

In this work, we investigate the scalarization of the Reissner–Nordström black hole within a scalar–tensor teleparallel gravity framework. This approach enables a direct comparison between scalarization mechanisms induced by a scalar field nonminimally coupled to the torsion scalar and those resulting from its coupling to the electromagnetic invariant.

21. Space-time structure and phenomenology of Cartan Khronon theory

Lucy Zheng (University of Tartu)

Oral talk

Cartan Khronon framework provides a foundation for unconventional space-time structure with a clock field, dubbed ‘khronon’, which spontaneously breaks the symmetry between space and time. This allows gravitational theory to have a Spin(4) gauge structure with a Euclidean background. This talk aims to clarify the motivation for the Euclidean background, the procedure of dimensional Wick...

30. Spacetime energy in general teleparallel theory of relativity

Roald Heinrich Ivask (University of Tartu)

Oral or Poster

Because of the mixing of gravity and inertia in GR, no coordinate-independent local energy density of the gravitational field can be defined. Many years of theoretical explorations have revealed that the same GR field equations can also be derived from a more general teleparallel connection which carries torsion and nonmetricity while the curvature vanishes. After further development of the...

38. Static Spherically Symmetric Black Holes in regularised 4D Einstein-scalar-Gauss-Bonnet theory

Michal Stano (Institute of Mathematics of the Czech Academy of Sciences)

Oral or Poster

We investigate static, spherically symmetric black holes in regularised four-dimensional Einstein–scalar–Gauss–Bonnet gravity, with the aim of determining whether the theory admits non-asymptotically flat solutions beyond the known special cases. Working in standard spherical coordinates, we use a Frobenius-type expansion of the symmetry-reduced field equations to classify possible local...

40. Teleparallel regularization of the gravitational action

Martin Krssak (Comenius University in Bratislava)

Oral talk

Classical solutions with a finite action play an important role in the path integral quantization of gravity, black hole thermodynamics, and holography. While the teleparallel action avoids the need for boundary terms, it depends on a non-dynamical spin connection that effectively encodes the regularization. We study different choices of this spin connection, as well as various methods for...

29. Temperature and Diffusivity in Frame-Invariant Scalar-Tensor Gravity

Sotirios Karamitsos (University of Tartu)

Oral talk

Scalar-tensor theories of gravity are known to generically admit an effective imperfect fluid description, which leads to a natural interpretation of GR as a state of thermal equilibrium. In particular, it is possible to assign a temperature to nonminimally coupled fields, which increases as the theory deviates from GR. However, this temperature is conformally dependent, and can be arbitrarily...

57. The algebraic structure of gravity

Dr Jakob Palmkvist (Chalmers University of Technology)

Oral talk

It has been known since 1998 that the dynamics of the bosonic form fields in supergravity can be formulated as a twisted first-order self-duality relation in a Lie superalgebra. I will extend the formalism to the gravity sector and describe how Einstein's equations in vacuum can be derived in a similar way. Conversely, diffeomorphisms can be generalised and unified with gauge transformations...

53. The energy of gravitational plane waves in Einstein gravity

Tomi Koivisto (University of Tartu)

Poster

A covariant reformulation of Einstein gravity in terms of an auxiliary frame field renders the canonical Noether current for translations tensorial, and thereby admits a local covariant interpretation of gravitational-wave energy. For both weak spin-2 waves and exact plane waves, we recover the expected energy in a rigid detector frame, but zero energy in the canonical frame co-moving with the...

12. The Generalized Dirac Equation in the Metric-Affine Spacetimes

Prof. Muzaffer Adak (Pamukkale University)

Oral talk

We discuss the most general form of Dirac equation in the non-Riemannian spacetimes containing curvature, torsion and non-metricity. It includes all bases of the Clifford algebra $cl(1,3)$ within the spinor connection. We adopt two approaches. First, the generalized Dirac equation is directly formulated by applying the minimal coupling prescription to the original Dirac equation. It is...

17. The Gravitational Aspect of Information: The Physical Reality of Asymmetric "Distance"

Dr Armin van de Venn (University of Tartu)

Oral talk

We present information geometry from the perspective of divergences, which define a generally asymmetric notion of separation. From this starting point, we show how both the metric tensor and affine connection naturally emerge, and we emphasize the role of nonmetricity in this framework. Within this setting, we demonstrate that a Brownian bridge subject to a canonical physical constraint...

27. The teleparallel gravity and Noether's second theorem

Sebastian Brezina (Comenius University in Bratislava)

Oral talk

It is well known that the Teleparallel Equivalent of General Relativity (TEGR) is locally dynamically equivalent to General Relativity in the absence of matter. However, for decades, discussions have persisted about this equivalence when matter is present. These discussions primarily focus on the choice of coupling prescription, whether to use the metric teleparallel or the Levi-Civita one,...

44. Thermodynamics and Phase Structure of Dyonic Taub-NUT-AdS Spaces

Adel Awad (Ain Shams U & American University in Cairo)

Oral talk

We investigate the phase structures of Lorentzian Dyonic Taub-NUT-AdS spacetimes with spherical, flat, and hyperbolic horizon geometries. First, we construct a consistent approach for the thermodynamics of these solution, which is verified through the first law, the Gibbs-Duhem relation, and the generalized Smarr relation. Second, to analyze these phases we consider both canonical and mixed...

4. Unified field theories from cotangent bundle geometry: The Einstein Maxwell Equations

Christian Pfeifer (University of Bremen, ZARM)

Oral talk

The unification of all physical fields into one mathematical object and the derivation of all physical field equations from that object in one framework is a long-lasting endeavor in fundamental physics. We suggest a new approach to achieve this goal by encoding physical fields into the geometry of the 1-particle phase space on spacetime (the cotangent bundle) through Hamilton geometry. The...

37. Vacuum stability in Geometric Trinity of Gravity

Filippo Contino (Scuola Superiore Meridionale)

Oral talk

The decay of a metastable (false) vacuum is a crucial non-perturbative phenomenon, as it plays an important role in constraining Standard Model and beyond the Standard Model physics. In particular, it has been shown that gravity can have a significant impact on the calculation of the decay rate. In this context, it is natural to ask whether different but classically equivalent formulations of...

49. Wave Phenomena Across Scales as Tests of Gravity: The FuSe CA24101 Initiative

Dr Aneta Wojnar (University of Wroclaw)

Oral talk

This presentation introduces the FuSe Action (CA24101) and its main scientific challenges to a broad audience working on the mathematical formulation of fundamental interactions. A central focus of the talk is the role of thermodynamics in understanding physical phenomena. In particular, the presentation highlights the need for a consistent formulation of thermodynamics in systems governed by...

58. Weyl-type theorems in Galilei and Carroll geometry

Philip Schwartz (Leibniz Universität Hannover, Institut für Theoretische Physik)

Oral or Poster

A classic theorem of Weyl (1921) states that a Weyl metric—a natural generalisation of a pseudo-Riemannian metric—is uniquely determined by its conformal and projective structures. This theorem forms the basis for the famous Ehlers–Pirani–Schild (EPS) axiomatic reconstruction (1972) of Lorentzian spacetime structure from light rays and the worldlines of massive particles.

An equivalent...