Tootfinder

This https://arxiv.org/abs/2412.00193 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_qu…

Spacetime Markov length: a diagnostic for fault tolerance via mixed-state phases
We establish a correspondence between the fault-tolerance of local stabilizer codes experiencing measurement and physical errors and the mixed-state phases of decohered resource states in one higher dimension. Drawing from recent developments in mixed-state phases of matter, this motivates a diagnostic of fault-tolerance, which we refer to as the spacetime Markov length. This is a length scale determined by the decay of the (classical) conditional mutual information of repeated syndrome measure…

Scattering angle in a Topological Star spacetime: a self-force approach
Massimo Bianchi, Donato Bini, Giorgio Di Russo
https://arxiv.org/abs/2506.04876 htt…

Scattering angle in a Topological Star spacetime: a self-force approach
We compute the scattering angle for a scalar neutral probe undergoing unbound motion around a Topological Star, including self-force effects. Moreover we identify the `electro-magnetic' source of the background as Papapetrou Field compatible with the isometries and characterize Topological Stars by studying their sectional curvature, geometric transport along special curves and the gravitational energy content in terms of the super-energy tensors.

A novel test of gravity: Does spacetime geometry track matter density?
Camille Bonvin, Nastassia Grimm, Isaac Tutusaus
https://arxiv.org/abs/2506.04387 htt…

A novel test of gravity: Does spacetime geometry track matter density?
We propose a novel test of gravity that combines galaxy clustering with gravitational lensing. In general relativity, the evolution of matter density fluctuations and of the Weyl potential -- the sum of spatial and temporal distortions of the geometry -- are governed by the same growth function. In contrast, alternative theories of gravity that modify the relation between geometry and matter content can lead to differences in these two growths. Exploiting a recent method to directly measure the…

Spacetime symmetry-enriched SymTFT: from LSM anomalies to modulated symmetries and beyond
Salvatore D. Pace, \"Omer M. Aksoy, Ho Tat Lam
https://arxiv.org/abs/2507.02036

Spacetime symmetry-enriched SymTFT: from LSM anomalies to modulated symmetries and beyond
We extend the Symmetry Topological Field Theory (SymTFT) framework beyond internal symmetries by including geometric data that encode spacetime symmetries. Concretely, we enrich the SymTFT of an internal symmetry by spacetime symmetries and study the resulting symmetry-enriched topological (SET) order, which captures the interplay between the spacetime and internal symmetries. We illustrate the framework by focusing on symmetries in 1+1D. To this end, we first analyze how gapped boundaries of 2…

This https://arxiv.org/abs/2502.12687 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_hept…

Black Hole Chemistry Knows Extra Dimensions
: In this note, we study an extra dimension effect on the black hole chemistry in the 8-dimensional Einstein-Yang-Mills-Maxwell theory. The base spacetime contains 4- dimensional compact manifolds and an instanton on top of those. We demonstrate how the extra dimensions affect the phase transition and viable black hole sizes in the 4-dimensional Einstein frame through the black hole chemistry. We focus on asymptotically anti-de Sitter spacetimes for the effective 4-dimensional model obtained by…

Electromagnetism: an intrinsic approach to Hadamard's method of descent
Giuliano Angelone, Elisa Ercolessi, Paolo Facchi, Rocco Maggi, Giuseppe Marmo, Saverio Pascazio, Francesco V. Pepe
https://arxiv.org/abs/2506.05255

Electromagnetism: an intrinsic approach to Hadamard's method of descent
We present a systematic geometric framework for the dimensional reduction of classical electromagnetism based on the concept of descent along vector fields of invariance. By exploring the interplay between the Lie derivative and the Hodge star operator, we implement descent conditions on differential forms that reduce Maxwell's equations in four-dimensional spacetime to electromagnetic theories in lower dimensions. We also consider multiple descent along pairwise commuting vector fields of inva…

Gradient estimates and parabolic frequency monotonicity for positive solutions of the heat equation under generalized Ricci flow
Juanling Lu, Yu Zheng
https://arxiv.org/abs/2506.04937

Gradient estimates and parabolic frequency monotonicity for positive solutions of the heat equation under generalized Ricci flow
In this paper, we establish Li-Yau-type and Hamilton-type estimates for positive solutions to the heat equation associated with the generalized Ricci flow, under a less stringent curvature condition. Compared with [25] and [35], these estimates generalize the results in Ricci flow to this new flow under the weaker Ricci curvature bounded assumption. As an application, we derive the Harnack-type inequalities in spacetime and find the monotonicity of one parabolic frequency for positive solutions…

Coupling Electromagnetism to Torsion: Black Holes and Spin-Charge Interactions
Sebastian Bahamonde, Jorge Maggiolo, Christian Pfeifer
https://arxiv.org/abs/2507.02362

Coupling Electromagnetism to Torsion: Black Holes and Spin-Charge Interactions
The coupling between matter fields and gravity (encoded in the geometry of spacetime) can be realized in various ways. Most commonly, a minimal coupling principle is employed, meaning that all matter fields, except spinors, couple only to the spacetime metric, while spinors additionally couple to the spacetime connection. Non-minimal couplings between matter fields and spacetime curvature can arise, for example, from quantum field theory on curved spacetime through renormalization corrections, …

Symmetries and conservation laws in discrete spacetime
Samuel Richard Totorica
https://arxiv.org/abs/2506.02119 https://arxiv.org/pdf…

Symmetries and conservation laws in discrete spacetime
Noether's theorem connects symmetries to invariants in continuous systems, however its extension to discrete systems has remained elusive. Recognizing the lowest-order finite difference as the foundation of local continuity, a viable method for obtaining discrete conservation laws is developed by working in exact analogy to the continuous Noether's theorem. A detailed application is given to electromagnetism, where energy-momentum conservation laws are rapidly obtained in highly generalized for…

Synthetic crystal rotation with spacetime metamaterials
I\~nigo Liberal, Alejandro Manjavacas
https://arxiv.org/abs/2506.02495 https://

Synthetic crystal rotation with spacetime metamaterials
The interaction of light with rotating bodies has been historically limited to rotation frequencies much smaller than optical frequencies. Here, we investigate synthetic crystal rotations, i.e., spatiotemporal modulations mimicking the rotation of an anisotropic crystal, which grant access to large rotation frequencies. Spatiotemporal modulations change the fundamental symmetries of the electromagnetic field, breaking temporal and rotation symmetries, but preserving a spatiotemporal rotation sy…

Neutrino oscillations in the Ellis wormhole spacetime
Ya-Ru Wang, Shu-Jun Rong
https://arxiv.org/abs/2506.23905 https://arxiv.org/pdf…

Neutrino oscillations in the Ellis wormhole spacetime
Gravitational lensing is a powerful tool to probe compact astrophysical objects and the distribution of dark matter at large scales. As a counterpart of photons, lensed relativistic neutrinos could also be used to explore properties of curved spacetimes. In the present paper we consider neutrino oscillations in the Ellis wormhole (WH) spacetime in comparison with the widely discussed black hole (BH) spacetimes. We investigate the oscillations involving lensing effects with 2- and 3-flavor neutr…

This https://arxiv.org/abs/2505.00761 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_hept…

What is a photon in de Sitter spacetime?
The states of a single photon in four-dimensional de Sitter (dS) spacetime form a Unitary Irreducible Representation (UIR) of SO(1,4), which we call the photon UIR. While in flat spacetime photons are intimately tied to gauge symmetry, we demonstrate that in de Sitter, photon states emerge generically in any quantum field theory, even without an underlying U(1) gauge field. We derive a Källén-Lehmann representation for antisymmetric tensor two-point functions and show that numerous composite …

Probing Ultralight Axion-like Dark Matter $-$ A PTA-PPA Synergy
Ximeng Li, Yonghao Liu, Zu-Cheng Chen, Shi Dai, Boris Goncharov, Xiao-Song Hu, Qing-Guo Huang, Tao Liu, Jing Ren, Yu-Mei Wu, Xiao Xue, Xingjiang Zhu
https://arxiv.org/abs/2506.04871

Probing Ultralight Axion-like Dark Matter $-$ A PTA-PPA Synergy
Ultralight axion-like dark matter (ALDM) is a leading candidate in the dark matter realm, characterized by its prominent wave properties on astronomical scales. Pulsar Timing Arrays (PTAs) and Pulsar Polarization Arrays (PPAs) aim to detect this dark matter through timing and polarization measurements, respectively, of pulsars. The PTA relies on gravitational effects, as the ALDM halo perturbs the spacetime metric within the Milky Way, while the PPA detects non-gravitational effects, namely cos…

Perturbations of Einstein-Maxwell-phantom spacetime: Instabilities of charged Ellis wormholes and quasinormal modes of black holes
Guan-Yu Wu, Si-Yu Wang, Yan-Gang Miao
https://arxiv.org/abs/2507.02258

Perturbations of Einstein-Maxwell-phantom spacetime: Instabilities of charged Ellis wormholes and quasinormal modes of black holes
Phantom scalar fields, as a viable candidate for dark energy, have been instrumental in eliminating spacetime singularities and constructing wormholes and regular black holes. We investigate the Einstein-Maxwell-phantom (EMP) framework, in which the Ellis wormholes can be charged and regular black holes can be admitted. While the previous study has shown the stability of EMP wormholes under massless scalar field perturbations, we further perform a comprehensive linear analysis of the EMP spacet…

This https://arxiv.org/abs/2506.00951 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Physics-Informed Neural Networks for the Relativistic Burgers Equation in the Exterior of a Schwarzschild Black Hole
We introduce a Physics-Informed Neural Networks(PINN) to solve a relativistic Burgers equation in the exterior domain of a Schwarzschild black hole. Our main contribution is a PINN architecture that is able to simulate shock wave formations in such curved spacetime, by training a shock- aware network block and introducing a Godunov-inspired residuals in the loss function. We validate our method with numerical experiments with different kinds of initial conditions. We show its ability to reprodu…

Quantum light and radiation in Rindler spacetime: from uncertainty relations to the cosmological implications
Fujin Wang, Syed Masood, L. G. Wang
https://arxiv.org/abs/2506.02417 …

Quantum light and radiation in Rindler spacetime: from uncertainty relations to the cosmological implications
Based on an analogy between diffraction integral formalism of classical field propagation and Feynman path integral approach to quantum field theory, we develop a quantum model for light and radiation in Rindler spacetime. The framework helps to reveal acceleration-induced contributions to the traditional Heisenberg position-momentum uncertainty relation. A modified Planck energy density distribution of radiation is established and reveals equivalence between temperature and Rindler acceleratio…

This https://arxiv.org/abs/2502.17570 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Effects of spacetime geometry on neutrino oscillation inside a Core-Collapse Supernova
Neutrinos are excellent probes of the inner structures of supernovas. However, an understanding of their dynamics remains incomplete, which is crucial for properly interpreting the detector data. The huge matter density inside a core collapse supernova affects the self-coupling of the neutrinos through a geometrical four-fermion interaction induced by spacetime torsion generated by the fermions themselves. For normal mass hierarchy, the effect is negligible; for inverted mass hierarchy however,…

S-algebra in Gauge Theory: Twistor, Spacetime and Holographic Perspectives
Adam Kmec, Lionel Mason, Romain Ruzziconi, Atul Sharma
https://arxiv.org/abs/2506.01888

S-algebra in Gauge Theory: Twistor, Spacetime and Holographic Perspectives
The celestial $S$-algebra arose from a reinterpretation of collinear limits of the Yang-Mills S-matrix as OPEs in celestial holography. It was subsequently represented via asymptotic charge aspects defined in the Yang-Mills radiative phase space defined at null infinity on the one hand, and via a twisted holography vertex algebra construction in twistor space on the other. Here we first identify it with the traditional symmetry algebra of self-dual Yang-Mills theory as an integrable system via …

The Klein-Gordon equation on asymptotically Minkowski spacetimes: the Feynman propagator
Dean Baskin, Moritz Doll, Jesse Gell-Redman
https://arxiv.org/abs/2507.01600

The Klein-Gordon equation on asymptotically Minkowski spacetimes: the Feynman propagator
We develop a theory of Feynman propagators for the massive Klein--Gordon equation with asymptotically static perturbations. Building on our previous work on the causal propagators, we employ a framework based on propagation of singularities estimates in Vasy's 3sc-calculus. We combine these estimates to prove global spacetime mapping properties for the Feynman propagator, and to show that it satisfies a microlocal Hadamard condition. We show that the Feynman propagator can be realized as the …

Set-lists primed and ready for the trad jazz that ain't yer dad's trad @… at the spacetime place of #Toronto #DromTaberna Friday June 6th 8pm.
It's like Bix said, why do I like this #jazz? Because I don't know what's going to happen next, do you? Nolan, Pat Smith, Patricio Llovet and I will be joined by Paul Callander and Sean McCarthy for you #jazzintoronto heads, I heard 'bass sax' and signed on! So, really, anything is possible! 😊
there is only a quantum probability we will resemble this:

Covariant Lie Derivatives and (Super-)Gravity
Grigorios Giotopoulos
https://arxiv.org/abs/2507.00140 https://arxiv.org/pdf/2507.00140…

Covariant Lie Derivatives and (Super-)Gravity
The slightly subtle notion of covariant Lie derivatives of \textit{bundle-valued} differential forms is crucial in many applications in physics, notably in the computation of conserved currents in gauge theories, and yet the literature on the topic has remained fragmentary. This note provides a complete and concise mathematical account of covariant Lie derivatives on a spacetime (super-)manifold $M,$ defined via choices of lifts of spacetime vector fields to principal $G$-bundles over it, or eq…

Conservation Laws and Boundedness for Linearised Einstein--Maxwell Equations on the Reissner--Nordstr\"om Black Hole
Marios A. Apetroaie, Sam C. Collingbourne, Elena Giorgi
https://arxiv.org/abs/2506.04812

Conservation Laws and Boundedness for Linearised Einstein--Maxwell Equations on the Reissner--Nordström Black Hole
We study the linearised Einstein--Maxwell equations on the Reissner--Nordström spacetime and derive the canonical energy conservation law in double null gauge. In the spirit of the work of Holzegel and the second author, we avoid any use of the hyperbolic nature of the Teukolsky equations and rely solely on the conservation law to establish control of energy fluxes for the gauge-invariant Teukolsky variables, previously identified by the third author, along all outgoing null hypersurfaces, for…

Periodic Orbits and Gravitational Wave Radiation of Black Holes in 4D-EGB gravity
Liping Meng, Zhaoyi Xu, Meirong Tang
https://arxiv.org/abs/2506.05015 htt…

Periodic Orbits and Gravitational Wave Radiation of Black Holes in 4D-EGB gravity
In the paper, we study the dynamical behavior of a particle around a charged black hole within the framework of 4D-EGB gravity theory. Based on the spacetime metric of the black hole, we rigorously derived the effective potential of the particle and analyzed the particle's MBO and ISCO. The results show that the key physical quantities of MBO and ISCO-including orbital radius, angular momentum, and energy-all exhibit significant dependence on parameter $α$ and charge $Q$. As these two paramete…

This https://arxiv.org/abs/2502.08748 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Vacuum Polarization, Geodesic Equation and Sachs-Wolfe Effect
We show that the null geodesic equation for photons is modified in the presence of a charged scalar field, with quantum fluctuations acting as an effective mass term that changes the null paths to timelike curves. This effect can be interpreted as a vacuum polarization phenomenon in curved spacetime. The resulting contribution to the Sachs-Wolfe effect varies with photon frequency, leading to frequency-dependent corrections to the cosmic microwave background (CMB) blackbody spectrum in the form…

On conformal Komar currents in LRS spacetimes
Abbas M. Sherif
https://arxiv.org/abs/2506.04888 https://arxiv.org/pdf/2506.04888

On conformal Komar currents in LRS spacetimes
For locally rotationally symmetric (LRS) spacetimes, we construct two equivalent forms of the Komar current derived from a conformal Killing vector. One is a kinematic construction and the other is in terms of the matter quantities on the spacetime. The required conservation condition for the current is derived and discussed in various instances, and the implications of the conservation of the current, and in the case of a vanishing current, are analyzed. A relationship between the conservation…

The Generalized Dirac Equation in the Metric Affine Spacetime
Muzaffer Adak, Ali Bagci, Caglar Pala, Ozcan Sert
https://arxiv.org/abs/2506.23609 https://…

The Generalized Dirac Equation in the Metric Affine Spacetime
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 referred to as the {\it direct Dirac equation} for seek of clarity and to preserve the tractability. Secon…

Physics-Informed Neural Networks for the Relativistic Burgers Equation in the Exterior of a Schwarzschild Black Hole
Shuyang Xiang
https://arxiv.org/abs/2506.00951

Physics-Informed Neural Networks for the Relativistic Burgers Equation in the Exterior of a Schwarzschild Black Hole
We introduce a Physics-Informed Neural Networks(PINN) to solve a relativistic Burgers equation in the exterior domain of a Schwarzschild black hole. Our main contribution is a PINN architecture that is able to simulate shock wave formations in such curved spacetime, by training a shock- aware network block and introducing a Godunov-inspired residuals in the loss function. We validate our method with numerical experiments with different kinds of initial conditions. We show its ability to reprodu…

This https://arxiv.org/abs/2505.20078 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_hept…

Notes on Rindler wave packets in Minkowski spacetime
We consider wave packets of a massless scalar field that have well-localized Rindler energy, and examine how their energy appears to a Minkowski observer to see how the classical gravitational blue-shift formula is modified quantum mechanically. We derive, by using the saddle point approximation, an analytic expression for the Minkowski momentum distribution of such Rindler wave packets. We find a universal lower bound on the uncertainty of Minkowski momentum; the momentum distribution can neve…

Black hole optical analogue: photon sphere microlasers
Chenni Xu, Aswathy Sundaresan, Nazire-Beg\"um Kazkal, Clement Lafargue, Lior Zarfaty, Li-Gang Wang, Ofek Birnholtz, Dominique Decanini, Melanie Lebental, Patrick Sebbah
https://arxiv.org/abs/2507.01751

Black hole optical analogue: photon sphere microlasers
The bell-like ringdown of the gravitational field in the last stage of the merging of massive black holes is now routinely detected on earth by the last generation of gravitational wave detectors. Its spectrum is interpreted as a sum of damped sinusoidal vibrations of the spacetime in the vicinity of the black hole. These so-called quasinormal modes are currently the subject of extensive studies, yet, their true nature remains elusive. Here, we emulate, in the laboratory, genuine four-dimension…

Anomaly of conserved and nonconserved axial charges in Hamiltonian lattice gauge theory
Yoshimasa Hidaka, Arata Yamamoto
https://arxiv.org/abs/2506.01336 h…

Anomaly of conserved and nonconserved axial charges in Hamiltonian lattice gauge theory
We investigate the axial anomaly in Hamiltonian lattice gauge theory. The definition of axial charge operators is ambiguous, especially between conserved and nonconserved axial charges. While these charges appear to differ only by a higher-order term in lattice spacing, they do not coincide in the continuum limit. We demonstrate, through analytical and numerical calculations, that the conserved axial charge correctly reproduces the axial anomaly relation in continuous spacetime. Our finding wou…

This https://arxiv.org/abs/2505.03551 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_qu…

From Mass-Shell Factorisation to Spin: An Attempt at a Matrix-Valued Liouville Framework for Relativistic Classical and Quantum Phase-Spacetime
While Liouville's theorem is first-order in time for the phase-space distribution itself, the relativistic mass-shell constraint $p^μp_μ= m^2$ is naively second-order in energy. We argue that it is reasonable to unify both energy branches within a single Hamiltonian by factorizing $(p^2 - m^2)$ in analogy with Dirac's approach in relativistic quantum mechanics. We show the resulting matrix-based Liouville equation remains first order and naturally yields a $4\times4$ matrix-valued probability…

This https://arxiv.org/abs/2412.01012 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Optimal transport and regularity of weak Kantorovich potentials on a globally hyperbolic spacetime
We consider the optimal transportation problem on a globally hyperbolic spacetime for some cost function $c_2$, which corresponds to the optimal transportation problem on a complete Riemannian manifold where the cost function is the Riemannian distance squared. Building on insights from previous studies on the Riemannian and Lorentzian case, our main goal is to investigate the regularity of $π$-solutions (weak versions of Kantorovich potentials), from which we can conclude, in a classical way,…

Singularity Avoidance in Gravitational Collapse of an Inhomogeneous Fluid in Rastall Gravity
Akbar Jahan, Halime Miraghaei, Shayesteh Ghaffari, Amir Hadi Ziaie
https://arxiv.org/abs/2507.02026

Singularity Avoidance in Gravitational Collapse of an Inhomogeneous Fluid in Rastall Gravity
Various types of inhomogeneous collapse models in general relativity (GR) lead to the formation of spacetime singularities either visible or hidden by a spacetime horizon. Our aim in the present work is to search for nonsingular models in Rastall gravity that arise as the final outcomes of spherically symmetric gravitational collapse of an inhomogeneous matter cloud. We firstly assume linear equations of state (EoS) for radial and tangential pressure profiles, i.e., $p_r=w_rρ$ and $p_θ=w_θρ…

This https://arxiv.org/abs/2306.15290 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_hept…

On boundary degrees of freedom in three dimensional Anti-de Sitter spacetime and thermofield-double
We will give two representations for thermofield-double (TFD). The first representation is the well-known Kerr-BTZ black hole geometry, which is the solution of Einstein's equation. The second representation is a disjoint union of two circles, which is a solution to two copies of the Schwarzian theory. This representation, in particular, admits the reparametrization modes, which are absent in any two dimensional CFT on a torus, and are essential for (dis-)entangling the TFD. Since the two repre…

Scalable Spatiotemporal Modeling for Bicycle Count Prediction
Rishikesh Yadav, Alexandra M. Schmidt, Aurelie Labbe, Pratheepa Jeganathan, Luis F. Miranda-Moreno
https://arxiv.org/abs/2506.07582

Scalable Spatiotemporal Modeling for Bicycle Count Prediction
We propose a novel sparse spatiotemporal dynamic generalized linear model for efficient inference and prediction of bicycle count data. Assuming Poisson distributed counts with spacetime-varying rates, we model the log-rate using spatiotemporal intercepts, dynamic temporal covariates, and site-specific effects additively. Spatiotemporal dependence is modeled using a spacetime-varying intercept that evolves smoothly over time with spatially correlated errors, and coefficients of some temporal co…

Spacetime reconstruction by order and number
Mathias Braun
https://arxiv.org/abs/2507.01907 https://arxiv.org/pdf/2507.01907

Spacetime reconstruction by order and number
We show that the random adjacency matrices induced by the chronological relations and i.i.d. samples of two spacetimes coincide in law if and only if the spacetimes in question are smoothly isometric. A similar result holds for weighted spacetimes. In the smooth framework of our article, this relaxes the hypotheses of the recent Gromov reconstruction theorem in Lorentzian signature by Braun-Sämann from a.s. isometry of the respective time separation functions to a.s. order isometry. In a proba…

A hyperboloidal method for numerical simulations of multidimensional nonlinear wave equations
Oliver Rinne
https://arxiv.org/abs/2507.00674 https://…

A hyperboloidal method for numerical simulations of multidimensional nonlinear wave equations
We consider the scalar wave equation with power nonlinearity in n+1 dimensions. Unlike previous numerical studies, we go beyond the radial case and do not assume any symmetries for n=3, and we only impose an SO(n-1) symmetry in higher dimensions. Our method is based on a hyperboloidal foliation of Minkowski spacetime and conformal compactification. We focus on the late-time power-law decay (tails) of the solutions and compute decay exponents for different spherical harmonic modes, for subcritic…

Shock formation in 1D conservation laws I: Inviscid structure
John Anderson, Sanchit Chaturvedi, Cole Graham
https://arxiv.org/abs/2506.17148 https://

Shock formation in 1D conservation laws I: Inviscid structure
We study the stability and structure of shock formation in 1D hyperbolic conservation laws. We show that shock formation is stable near shocking simple waves: perturbations form a shock nearby in spacetime. We also characterize the boundary of the classical development in a spacetime neighborhood of the first time singularity. Finally, we describe the precise nature of nondegenerate shock formation through an expansion in homogeneous functions of fractional degree. We use these results in a com…

Helically twisted spacetime: study of geometric and wave optics, and physical analysis
Edilberto O. Silva, Frankbelson dos S. Azevedo, Faizuddin Ahmed
https://arxiv.org/abs/2506.23291

Helically twisted spacetime: study of geometric and wave optics, and physical analysis
We analyse a stationary, cylindrically symmetric spacetime endowed with an intrinsic helical twist, $ds^{2} = -dt^{2} + dr^{2} + r^{2} dϕ^{2} + (dz + ω\, r\,dϕ)^{2}$. Solving the Einstein equations exactly yields an anisotropic energy-momentum tensor whose density is negative and decays as $r^{-2}$, thus violating the weak energy condition near the axis. Three notable features emerge: (i) axis-centred negative energy; (ii) unequal transverse stresses; (iii) a torsional momentum flux $T_{ϕz}…

Gravitational Wave Signals in a Promising Realization of SO(10) Unification
Injun Jeong (Center for Quantum Spacetime, Sogang University, Department of Physics, Sogang University), J\"orn Kersten (Department of Physics and Technology, University of Bergen, Department of Physics and IPAP, Yonsei University), Stefano Scopel (Center for Quantum Spacetime, Sogang University, Department of Physics, Sogang University), Liliana Velasco-Sevilla (Center for Quantum Spacetime, Sogang Univer…

Gravitational Wave Signals in a Promising Realization of SO(10) Unification
We investigate gravitational wave signals in a non-supersymmetric grand unified model where the group $SO(10)$ is broken in two steps to the Standard Model gauge group. We calculate the analytical form of the one-loop effective potential responsible for the first step of symmetry breaking and show that it can lead to a first-order phase transition with gravitational wave production. We also determine the gravitational wave background produced by the primordial plasma of relativistic particles. …

Numerical analysis of quasiperiodic oscillations in the Hartle-Thorne spacetime
K. Boshkayev, T. Konysbayev, Ye. Kurmanov, M. Muccino, H. Quevedo
https://arxiv.org/abs/2506.11581 …

Numerical analysis of quasiperiodic oscillations in the Hartle-Thorne spacetime
We numerically analyze quasiperiodic oscillations (QPOs) using a well-established spacetime model with neutron star sources. Within the framework of general relativity, we present expressions for the fundamental frequencies of test particles in the gravitational field of a slowly rotating and slightly deformed compact object defined by the Hartle-Thorne (HT) metric. Using the Relativistic Precession Model (RPM) formulated by Stella and Morinsk, we examine quasiperiodic oscillation data from eig…

Quantum stress-energy at timelike boundaries: testing a new beyond-$\Lambda$CDM parameter with cosmological data
Oliver H. E. Philcox, Eva Silverstein, Gonzalo Torroba
https://arxiv.org/abs/2507.00115

Quantum stress-energy at timelike boundaries: testing a new beyond-$Λ$CDM parameter with cosmological data
We analyze the basic cosmological effects of a population of timelike boundaries -- a form of nontrivial spacetime topology -- containing a boundary layer of quantum stress energy. This accumulation of vacuum fluctuations of quantum fields can be consistently negative and UV sensitive, providing an additional source of cosmic energy density strong enough to compete with matter and dark energy. For boundary conditions enabling a solution with fixed comoving boundary size, this effect contributes…

This https://arxiv.org/abs/2505.16026 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_hept…

Edge modes of tetrad gravity: Unlike diffeomorphisms, all shifts are integrable
We present an improved notion of internal tetrad shifts in 4 dimensions which is always integrable in the presence of corners. This allows us to study the fully extended corner symmetry algebra of gauge charges, which is a deformation of $ISO(1,3)^S$ involving spacetime curvature. We argue this implies corner noncommutativity of the spin connection $ω$. The latter in particular hints that an extended BF theory might be a better way understand the dynamics of tetrad gravity. This result present…

Compact binary systems in Einstein-{\AE}ther gravity. II. Radiation reaction to 2.5 post-Newtonian order
Fatemeh Taherasghari, Clifford M. Will
https://arxiv.org/abs/2506.03843

Compact binary systems in Einstein-Æther gravity. II. Radiation reaction to 2.5 post-Newtonian order
We obtain the equations of motion for compact binary systems (black holes or neutron stars) in an alternative theory of gravity known as Einstein-AEther theory, which supplements the standard spacetime metric with a timelike four-vector (the AEther field) that is constrained to have unit norm. The equations make use of solutions obtained in Paper I for the gravitational and AEther field potentials within the near zone of the system, evaluated to 2.5 post-Newtonian (PN) order ($O(v/c)^5$ beyond …

Quantum multicriticality and emergent symmetry in Dirac systems with two order parameters at three-loop order
Max Uetrecht, Igor F. Herbut, Michael M. Scherer, Emmanuel Stamou, Tom Steudtner
https://arxiv.org/abs/2505.22723

Quantum multicriticality and emergent symmetry in Dirac systems with two order parameters at three-loop order
Two-dimensional materials with interacting Dirac excitations can host quantum multicritical behavior near the phase boundaries of the semimetallic and two-ordered phases. We study such behavior in Gross--Neveu--Yukawa field theories where $N_f$ flavors of Dirac fermions are coupled to two order-parameter fields with $SO(N_A)$ and $SO(N_B)$ symmetry, respectively. To that end, we employ the perturbative renormalization group up to three-loop order in $4-ε$ spacetime dimensions. We distinguish t…

Measurements in stochastic gravity and thermal variance
Markus B. Fr\"ob, Dra\v{z}en Glavan, Paolo Meda
https://arxiv.org/abs/2506.23193 https://

Measurements in stochastic gravity and thermal variance
We analyze the thermal fluctuations of a free, conformally invariant, Maxwell quantum field (photon) interacting with a cosmological background spacetime, in the framework of quantum field theory in curved spacetimes and semiclassical and stochastic gravity. The thermal fluctuations give rise to backreaction effects upon the spacetime geometry, which are incorporated in the semiclassical Einstein-Langevin equation, evaluated in the cosmological Friedmann-Lemaître-Robertson-Walker spacetime. We…

$\mathrm{SL}(2,\mathbb{R})$ families of Kerr black holes
Robert Penna
https://arxiv.org/abs/2506.00184 https://arxiv.org/pdf/2506.001…

$\mathrm{SL}(2,\mathbb{R})$ families of Kerr black holes
The stationary, axisymmetric sector of vacuum general relativity (with zero cosmological constant) enjoys an $\mathrm{SL}(2,\mathbb{R})$ symmetry called the Matzner-Misner group. We study the action of the Matzner-Misner group on the Kerr black hole. We show that the group acts naturally on a three parameter generalization of the usual two parameter Kerr solution. The new parameter represents a large diffeomorphism which gives the spacetime an asymptotic angular velocity. We explain how the $\m…

Ultra High Energy Neutrino Event KM3-230213A as a Signal of Electroweak Vacuum Turbulence in Merging Black Hole Binaries
Alexander S. Sakharov, Rostislav Konoplich, Merab Gogberashvili
https://arxiv.org/abs/2506.23387

Ultra High Energy Neutrino Event KM3-230213A as a Signal of Electroweak Vacuum Turbulence in Merging Black Hole Binaries
The recent detection of the ultra-high-energy neutrino event KM3-230213A ($\sim$220 PeV) by KM3NeT telescope poses a challenge to conventional astrophysical models, particularly in light of the absence of similar $\gtrsim$100 PeV events in IceCube data, despite its larger exposure. We propose a novel mechanism in which binary black hole mergers act as transient neutrino sources via gravitationally induced electroweak vacuum instability. In this scenario, the extreme spacetime curvature near the…

This https://arxiv.org/abs/2410.20529 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Formation of nonsingular spherical black holes with holonomy corrections
We present a canonical model of spherical gravity with covariant corrections motivated by loop quantum gravity. The effective Hamiltonian defines univocally a family of geometries that generalizes the Lemaître-Tolman-Bondi spacetimes, and they can be matched to the vacuum of the theory across a timelike hypersurface comoving with the flow of matter. Such is precisely the complete spacetime picture of a spherical star subject to its own gravitational pull. The singularity gets replaced with a s…

State updates and useful qubits in relativistic quantum information
Jos\'e Polo-G\'omez, T. Rick Perche, Eduardo Mart\'in-Mart\'inez
https://arxiv.org/abs/2506.18906

State updates and useful qubits in relativistic quantum information
We address the longstanding challenge of consistently updating quantum states after selective measurements in a relativistic spacetime. Standard updates along the future lightcones preserve causality but break correlations between causally disconnected parties, whereas updates along the past lightcone either imply retrocausality or do not respect the causal propagation of information. We introduce a minimal extension of multipartite states to encode subsystem-specific contextual information. Th…

Torsional modulation of atmospheric neutrino oscillation
Riya Barick, Amitabha Lahiri
https://arxiv.org/abs/2506.19354 https://arxiv.…

Torsional modulation of atmospheric neutrino oscillation
Fermions act as sources of spacetime torsion. However, this torsion is non-dynamical and can be eliminated using its equations of motion. The resulting theory features an effective four-fermion interaction in a torsion-free background. Generically this interaction is non-universal and violates parity. When neutrinos propagate through matter, they experience the effect of this geometrical interaction, which is similar to the MSW effect, but diagonal in the mass basis. Since this quartic interact…

The $Spin(4)$ gauge theory of space, time, gravitation, matter and dark matter
Tomi Koivisto, Lucy Zheng, Tom Zlosnik
https://arxiv.org/abs/2507.00968 http…

The $Spin(4)$ gauge theory of space, time, gravitation, matter and dark matter
A novel gauge-theoretic framework for spacetime and gravitation is proposed, in which a {\it Cartan khronon} field dynamically breaks the symmetry between space and time, enabling the emergence of temporality within a fundamentally Euclidean setting. Based on a $Spin(4)$ gauge structure, the theory provides a real-valued formulation of chiral spacetime, wherein the effects typically attributed to dark matter could instead be explained by the dynamics of gravitation. New results are presented wi…

This https://arxiv.org/abs/2505.14446 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Light deflection in unified gravity and measurable deviation from general relativity
Light, though massless, does not travel in a perfectly straight line when it passes near a massive object. Instead, it follows the curvature of spacetime - a phenomenon predicted by Einstein's general theory of relativity. This effect, known as gravitational lensing, occurs because massive bodies like stars, galaxies, or black holes distort the fabric of spacetime around them, bending the path of light much like a lens bends rays in optics. In this work, we study gravitational lensing using the…

Emergent Holographic Spacetime from Quantum Information
Tadashi Takayanagi
https://arxiv.org/abs/2506.06595 https://arxiv.org/pdf/250…

Emergent Holographic Spacetime from Quantum Information
Holographic duality describes gravitational theories in terms of quantum many-body systems. In holography, quantum information theory provides a crucial tool that directly connects microscopic structures of these systems to the geometries of gravitational spacetimes. One manifestation is that the entanglement entropy in quantum many-body systems can be calculated from the area of an extremal surface in the corresponding gravitational spacetime. This implies that a gravitational spacetime can em…

This https://arxiv.org/abs/2505.01312 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Dynamical dark energy and gravitational coupling from moving geometries
We introduce the notion of moving Cartan geometries described by quotients of Lie groups and Lie algebras with spacetime dependant structure constants and construct associated deformed topological gauge action functionals for Lorentzian (including dS and AdS) and Lorentz$\times$Weyl moving geometries. The actions feature a generalization of the Nieh-Yan topological term for a varying coupling constant. We compute the equations of motion of the gauge $+$ matter actions and show that they dictate…

This https://arxiv.org/abs/2505.23679 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Boundary terms in cosmology
In the derivation of the Einstein field equations via Hamilton's principle, the inclusion of a boundary term is essential to render the variational problem well-posed, as it addresses variations that do not vanish at the boundary of the spacetime manifold. Typically, this term is chosen as the Gibbons-Hawking-York boundary term. In this work, we propose an alternative treatment of the boundary term within a cosmological framework by employing the Lagrange multiplier method. This approach enforc…

Einstein causality of quantum measurements in the Tomonaga-Schwinger picture
Samuel Fedida
https://arxiv.org/abs/2506.14693 https://a…

Einstein causality of quantum measurements in the Tomonaga-Schwinger picture
When quantum measurements are conducted over spacelike-separated regions of spacetime, a natural and commonly assumed physical postulate, called Einstein causality, asserts that they should commute. In this paper, we provide a generalisation to Lüders' rule à la Aharonov-Albert in those globally hyperbolic spacetimes which allow unitarily equivalent Hilbert spaces to be defined along Cauchy hypersurfaces, thus relying on the existence of an interaction picture à la Tomonaga-Schwinger. We sho…

Dynamical-System analysis of single-axion monodromy inflation with periodically-modulated potentials
Panagiotis Dorlis, Nick E. Mavromatos, Sotirios-Neilos Vlachos, Makarios Vyros
https://arxiv.org/abs/2507.02746

Dynamical-System analysis of single-axion monodromy inflation with periodically-modulated potentials
In this work, we study field theoretic systems of a single axion-like field with linear potentials modulated by cosine terms, allegedly induced by non-perturbative instanton configurations. These systems are considered in expanding-Universe spacetime backgrounds (of Friedman-Lema$\hat{\rm i}$tre-Robertson-Walker type). Using a dynamical-system approach, we classify the various de-Sitter like (inflationary) vacua from the point of view of their stability, which depend on the values of the model …

This https://arxiv.org/abs/2505.15886 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_hept…

Fundamental Complement of a Gravitating Region
Any gravitating region $a$ in any spacetime gives rise to a generalized entanglement wedge, the hologram $e(a)$. Holograms exhibit properties expected of fundamental operator algebras, such as strong subadditivity, nesting, and no-cloning. But the entanglement wedge EW of an AdS boundary region $B$ with commutant $\bar B$ satisfies an additional condition, complementarity: EW$(B)$ is the spacelike complement of EW$(\bar B)$ in the bulk. Here we identify an analogue of the boundary commutant $…

Exploring black hole shadows in axisymmetric spacetimes with coordinate-independent methods and neural networks
Temurbek Mirzaev, Bobomurat Ahmedov, Cosimo Bambi
https://arxiv.org/abs/2507.02520

Exploring black hole shadows in axisymmetric spacetimes with coordinate-independent methods and neural networks
The study of black hole shadows provides a powerful tool for testing the predictions of general relativity and exploring deviations from the standard Kerr metric in the strong gravitational field regime. Here, we investigate the shadow properties of axisymmetric gravitational compact objects using a coordinate-independent formalism. We analyze black hole shadows in various spacetime geometries, including the Kerr, Taub-NUT, $γ$, and Kaluza-Klein metrics, to identify distinctive features that c…

This https://arxiv.org/abs/2403.05284 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Gravity as a deformed topological gauge theory
We describe gauge theories which allow to retrieve a large class of gravitational theories, including, MacDowell-Mansouri gravity and its topological extension to Loop Quantum Gravity via the Pontrjagin characteristic class involving the Nieh-Yan term. Considering symmetric spaces parametrized by mutations allows to naturally obtain a bare cosmological constant which in particular cases gives rise to a positive effective cosmological constant while having an AdS spacetime. Two examples are st…

Entangled Unruh-DeWitt detectors amplify quantum coherence
Shu-Min Wu, Yu-Xuan Wang, Wentao Liu
https://arxiv.org/abs/2506.14115 https://

Entangled Unruh-DeWitt detectors amplify quantum coherence
We explore the quantum coherence between a pair of entangled Unruh-DeWitt detectors, interacting with a quantum field, using a nonperturbative approach in a (3+1)-dimensional Minkowski spacetime with instantaneous switching ($δ$-switching). It is intriguing to observe that for a maximally entangled state, increasing the coupling strength enhances the detectors' initial quantum coherence while simultaneously causing a monotonic decrease in their initial entanglement. This reveals a remarkable p…

Anisotropic conformal Carroll field theories and their gravity duals
Emilie Despontin, Stephane Detournay, Sudipta Dutta, Dima Fontaine
https://arxiv.org/abs/2505.23755

Anisotropic conformal Carroll field theories and their gravity duals
We investigate anisotropic conformal Carroll field theories and their holographic duals. On the field theory side, we focus on the case with scaling exponent $z=0$ in two and three spacetime dimensions. These theories exhibit infinite-dimensional symmetry algebras, including supertranslations and superrotations, and are closely related to, but distinct from, Warped Conformal Field Theories. We construct the associated Carrollian stress tensor, derive its transformation properties, and analyse t…

Quantum Effective Dynamics of Papapetrou Spacetime
Xiaokan Guo, Faqiang Yuan
https://arxiv.org/abs/2506.08821 https://arxiv.org/pdf/2…

Quantum Effective Dynamics of Papapetrou Spacetime
In this paper, we investigate the quantum effective dynamics of Papapetrou spacetime by using methods from loop quantum gravity. The Papapetrou spacetime is an extension of the Schwarzschild spacetime with an extra coupled anti-scalar field. By solving the equations of motion generated by the Hamiltonian constraint for Papapetrou spacetime, we can construct the quantum effective metric. The resulting effective metric for the quantum-corrected Papapetrou spacetime demonstrates the quantum effect…

Bulk Spacetime Encoding via Boundary Ambiguities
Zhenkang Lu, Cheng Ran, Shao-feng Wu
https://arxiv.org/abs/2506.12890 https://arxiv.…

Bulk Spacetime Encoding via Boundary Ambiguities
We propose a method to reconstruct the exterior of a static, planar-symmetric black hole from an infinite set of discrete momentum-space locations, known as pole-skipping points, where the boundary Green's function becomes ambiguous. The reconstruction is fully analytical and involves solving only linear equations. It further enables a reinterpretation of any pure gravitational field equation in pole-skipping data. Moreover, our method reveals that the pole-skipping points are redundant: only a…

Quasinormal modes of nonlocal gravity black holes
Rocco D'Agostino, Vittorio De Falco
https://arxiv.org/abs/2507.01698 https://ar…

Quasinormal modes of nonlocal gravity black holes
We present a comprehensive study of the quasinormal modes of a new class of nonlocal static and spherically symmetric black hole (BH) solutions within the framework of the revised Deser-Woodard theory of gravity. These solutions are constructed as linear perturbations of the Schwarzschild spacetime and are characterized by an inverse power-law behavior of the lapse metric function. We derive the radial profiles of the effective potentials corresponding to scalar, electromagnetic and axial gravi…

Dirty Black Holes, Clean Signals: Near-Horizon vs. Environmental Effects on Grey-Body Factors and Hawking Radiation
Roman A. Konoplya, Thomas D. Pappas
https://arxiv.org/abs/2507.01954

Dirty Black Holes, Clean Signals: Near-Horizon vs. Environmental Effects on Grey-Body Factors and Hawking Radiation
Grey-body factors are not only essential ingredients for computing the intensity of Hawking radiation, but also serve as characteristics of black hole's geometry that are closely related to their quasinormal modes. Importantly, they tend to be more stable under small deformations of the background spacetime. In this work, we carry out a detailed analysis of grey-body factors and Hawking radiation for a spherically symmetric black hole subject to localized deformations which do not alter the Haw…

Observational Constraints on Scalar Field--Matter Interaction in Weyl Integrable Spacetime
Andronikos Paliathanasis
https://arxiv.org/abs/2506.16223 https:…

Observational Constraints on Scalar Field--Matter Interaction in Weyl Integrable Spacetime
We test an analytic cosmological solution within the framework of Weyl Integrable Spacetime using current observational data. In this model, dark energy is described by a pressureless fluid, while a scalar field arises naturally through the definition of the connection. This gravitational theory reveals a Chameleon Mechanism leading to a nonzero interaction between the scalar field and the matter sector. This model extends the standard $Λ$CDM cosmology by introducing one additional degree of f…

Gravity Duality of Networks
Yu Guo, Rong-Xin Miao
https://arxiv.org/abs/2506.21305 https://arxiv.org/pdf/2506.21305

Gravity Duality of Networks
The network has been attracting increasing attention for its role in driving the artificial intelligence revolution and enabling profound insights into gravity. This paper investigates the gravity dual of the conformal field theory defined on a network (AdS/NCFT). A typical network, consisting of edges and nodes, is dual to a spacetime with branches and connecting branes, which we refer to as Net-branes. We demonstrate that the junction condition on the Net-brane results in energy conservation …

This https://arxiv.org/abs/2503.10716 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Warm Inflation in $f(Q)$ gravity
This paper investigates warm inflation within the context of $f(Q)$ gravity for the Friedmann-Robertson-Walker spacetime. We formulate the governing field equations using slow-roll approximations and examine a power-law model to evaluate critical inflationary parameters including slow-roll parameters, scalar and tensor power spectra, and their associated spectral indices. The distinguishing feature of warm inflation lies in its fundamental premise that both radiation and inflaton coexist and in…

Holography with Null Boundaries
Christian Ferko, Savdeep Sethi
https://arxiv.org/abs/2506.20765 https://arxiv.org/pdf/2506.20765

Holography with Null Boundaries
One of the key issues in holography is going beyond $\mathrm{AdS}$ and defining quantum gravity in spacetimes with a null boundary. Recent examples of this type involve linear dilaton asymptotics and are related to the $T \overline{T}$ deformation. We present a holographic correspondence derived from string theory, which is an example of a kind of celestial holography. The holographic definition is a spacetime non-commutative open string theory supported on D1-D5 branes together with fundamenta…

This https://arxiv.org/abs/2412.06043 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Probing Gravity -- Fundamental Aspects of Metric Theories and their Implications for Tests of General Relativity
Guided by the Einstein equivalence principle that identifies the phenomenon of gravitation as a manifestation of the dynamics of spacetime in contrast to a localizable force, we review and explore its consequences on formulating a theory of gravity. The resulting space of metric theories of gravity may address open conceptual and observational puzzles through a wealth of effects beyond general relativity, whose traces can be searched for within today's and tomorrow's gravitational testing groun…

This https://arxiv.org/abs/2409.02188 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Stochastic dark matter: Covariant Brownian motion from Planckian discreteness
Quantum gravity has long remained elusive from an observational standpoint. Developing effective cosmological models motivated by the fundamental aspects of quantum gravity is crucial for bridging theory with observations. One key aspect is the granularity of spacetime, which suggests that free particles would deviate from classical geodesics by following a covariant Brownian motion. This notion is further supported by swerves models in causal set theory, a discrete approach to quantum gravity.…

Charged rotating quantum black holes
Dyuman Bhattacharya, Robie A. Hennigar, Robert B. Mann, Ming Zhanga
https://arxiv.org/abs/2506.19941 https://

Charged rotating quantum black holes
We investigate the thermodynamic and holographic properties of charged and rotating quantum black holes in a doubly holographic braneworld setup. These quantum black holes are derived from the anti-de Sitter C-metric and are exact solutions to a semi-classical gravitational theory which incorporates all orders of the backreaction of quantum fields on spacetime. The inclusion of both charge and rotation extends and generalizes previous studies. The thermodynamics and critical behavior of the bla…

Norm of the no-boundary state
Jordan Cotler, Kristan Jensen
https://arxiv.org/abs/2506.20547 https://arxiv.org/pdf/2506.20547

Norm of the no-boundary state
We consider Einstein gravity with positive cosmological constant coupled to matter in an asymptotically de Sitter universe with sphere boundary at timelike infinity. In this setting we show that, to one-loop order and at late time, the norm of the no-boundary state vanishes, going as $ e^{S_0} \frac{Z S_0^{-d(d+1)/4}}{\text{vol}(SO(d,1))}$ with $S_0$ the tree-level entropy of the static patch, $d$ the spacetime dimension, and $Z$ non-negative. While we expect a non-zero norm to arise at two loo…

Analytical solutions of CPT-odd Maxwell equations in Schwarzschild spacetime
Hao Wang, Zhi Xiao, Bing Sun
https://arxiv.org/abs/2506.10409 https://

Analytical solutions of CPT-odd Maxwell equations in Schwarzschild spacetime
In this work, we present the CPT-violating (CPTV) Maxwell equations in curved spacetime using the Newman-Penrose (NP) formalism. We obtain a semi-analytical solution to the Maxwell equations in Schwarzschild spacetime under the assumption that the CPT-odd $\left(k_{AF}\right)^μ$ term exhibits spherical symmetry in the Schwarzschild background. Retaining only terms up to linear order in the $\left(k_{AF}\right)^μ$ coefficient, we obtain perturbative solutions by treating the solutions of the L…

Observer Time from Causality in Perturbative Quantum Gravity
Allic Sivaramakrishnan
https://arxiv.org/abs/2506.16109 https://arxiv.or…

Observer Time from Causality in Perturbative Quantum Gravity
It is unclear whether an observable notion of time exists in quantum gravity even in principle because spacetime itself fluctuates. We propose a form of observable time in perturbative quantum gravity. First, we define an elapsed proper time in curved space using intersections of worldlines and future light cones. Here, time arises from causality via the dependence on light cones. We then propose that performing the gravitational path integral describes quantum gravity corrections to this notio…

Static Spherical Vacuum Solution to Bumblebee Gravity with Time-like VEVs
Hao Li, Jie Zhu
https://arxiv.org/abs/2506.17957 https://ar…

Static Spherical Vacuum Solution to Bumblebee Gravity with Time-like VEVs
The static spherical vacuum solution in a bumblebee gravity model where the bumblebee field \(B_μ\) has a time-like vacuum expectation value \(b_μ\) is studied. We show that in general curved spacetime solutions are not allowed and only the Minkowski spacetime exists. However, it is surprising that a non-trivial solution can be obtained so long as a unique condition for the vacuum expectation \(b^2\equiv -b^μb_μ=2/κ\), where \(κ=8πG\) is satisfied. We argue that naturally this solution i…

Observable signatures of Black Holes with Hernquist Dark Matter Halo having a cloud of strings: From Geodesics to Shadow
Faizuddin Ahmed, Ahmad Al-Badawi, \.Izzet Sakall{\i}
https://arxiv.org/abs/2506.18457

Observable signatures of Black Holes with Hernquist Dark Matter Halo having a cloud of strings: From Geodesics to Shadow
We present a comprehensive theoretical investigation of a novel black hole (BH) spacetime: a Schwarzschild BH embedded in a Hernquist-type dark matter halo (HDMH) and surrounded by a cloud of cosmic strings (CSs) -- collectively termed the Schwarzschild-HDMH with CS (SHDMHCS) configuration. By analyzing the spacetime geometry, we explore how key parameters -- the core radius and halo density of the dark matter, along with the string tension -- affect the geodesic motion of both massless and mas…

$N=1$ Supersymmetry invariance of the Abelian Stueckelberg model
M. A. L. Capri, D. R. Granado, I. F. Justo, L. S. S. Mendes
https://arxiv.org/abs/2506.17021

$N=1$ Supersymmetry invariance of the Abelian Stueckelberg model
In this paper we investigate the invariance of the Abelian Stueckelberg-like model under gauge and $N=1$ supersymmetric (SUSY) transformations in (3+1) spacetime. We show that the Stueckelberg-like mass term explicitly breaks $N=1$ supersymmetry under the Wess-Zumino (WZ) gauge condition. Nevertheless, we demonstrate that the WZ gauge is not needed in order to construct an action independent of compensating fields, manifestly supersymmetric and gauge invariant.

Pseudo-Complex Gravity as a Geometric Resolution of the Black Hole Information Paradox
Fridolin Weberand Peter O. Hess, Cesar A. Zen Vasconcellos
https://arxiv.org/abs/2506.21761 …

Pseudo-Complex Gravity as a Geometric Resolution of the Black Hole Information Paradox
We investigate the black hole information paradox in the setting of pseudo-complex gravity, a covariant geometric extension of general relativity that introduces a minimal length scale by deforming the spacetime manifold. In this framework, curvature invariants stay finite, and the classical singularity is geometrically regularized via a smooth core. We show that the correction term B/(6r**4) alters the Schwarzschild metric, generating the regularized geometry above, yielding a finite Hawking t…

Constraint on the Deviation of Kerr Metric via Bumpy Parameterization and Particle Swarm Optimization in Extreme Mass-Ratio Inspirals
Xiaobo Zou, Xingyu Zhong, Wen-Biao Han, Soumya D. Mohanty
https://arxiv.org/abs/2506.21955

Constraint on the Deviation of Kerr Metric via Bumpy Parameterization and Particle Swarm Optimization in Extreme Mass-Ratio Inspirals
Measurement of deviations in the Kerr metric using gravitational wave (GW) observations will provide a clear signal of new Physics. Previous studies have developed multiple parameterizations (e.g. ``bumpy" spacetime) to characterize such deviations in extreme mass ratio inspirals (EMRI) and employed analyses based on the Fisher information matrix (FIM) formalism to quantify the constraining power of space-borne GW detectors like LISA and Tianqin, e.g., achieving a constraint sensitivity levels …

High-frequency backreaction for the Einstein equations under $\mathbb U(1)$ symmetry: from Einstein-dust to Einstein-Vlasov
C\'ecile Huneau, Jonathan Luk
https://arxiv.org/abs/2506.21779

High-frequency backreaction for the Einstein equations under $\mathbb U(1)$ symmetry: from Einstein-dust to Einstein-Vlasov
Given suitable small, localized, $\mathbb U(1)$-symmetric solutions to the Einstein-massless Vlasov system in an elliptic gauge, we prove that they can be approximated by high-frequency vacuum spacetimes. This extends previous constructions where the limiting spacetime solves the Einstein-(multiple) null dust system (i.e., where the limiting massless Vlasov field can be written as a finite sum of delta measures). The proof proceeds by first approximating solutions to the Einstein-massless Vlaso…

Exploring the role of accretion disk geometry in shaping black hole shadows
Zi-Liang Wang
https://arxiv.org/abs/2506.21148 https://ar…

Exploring the role of accretion disk geometry in shaping black hole shadows
We study black hole imaging in the context of geometrically thick accretion disks in Schwarzschild spacetime. By decomposing the emitting region into a set of one-dimensional luminous segments, each characterized by its inclination angle and inner radius, we construct transfer functions that capture key image features-namely, the direct image, lensing ring, and photon ring. This approach allows a unified treatment of disk geometry and viewing angle. We explore three regimes: optically thin, opt…

Compact Cauchy horizons admit constant surface gravity
Raymond A. Hounnonkpe, Ettore Minguzzi
https://arxiv.org/abs/2506.20004 https://

Compact Cauchy horizons admit constant surface gravity
We prove that in any spacetime dimension and under the dominant energy condition, every totally geodesic connected smooth compact null hypersurface (hence every compact Cauchy horizon) admits a smooth lightlike tangent vector field of constant surface gravity. That is, we solve the open degenerate case by showing that, if there is a complete generator, then there exists a smooth future-directed geodesic lightlike tangent field. The result can be stated as an existence result for a particular co…

Exact vacuum solution with Hopf structure in general relativity
Junpei Harada
https://arxiv.org/abs/2506.20878 https://arxiv.org/pdf/…

Exact vacuum solution with Hopf structure in general relativity
An exact solution to the vacuum Einstein equations is presented, whose structure is based on the Hopf fibration. The solution employs a geodesic null vector field that defines a twisting congruence and appears in the metric in Kerr-Schild form. This solution is of Petrov type D and involves two parameters. Remarkably, the resulting spacetime is regular, with no curvature singularities. Both the Kretschmann scalar and the Chern-Pontryagin scalar are nonzero and remain finite throughout the space…

Dynamical Horizon Segments and Spacetime Isometries
Abhay Ashtekar, Badri Krishnan
https://arxiv.org/abs/2506.10190 https://arxiv.org…

Dynamical Horizon Segments and Spacetime Isometries
Given a space-time $(\mathscr{M}, g_{ab})$ admitting a dynamical horizon segment (DHS) $\mathscr{H}$, we show that there are stringent constraints on the Killing fields $ξ^a$ that $g_{ab}$ can admit in a neighborhood of $\mathscr{H}$: Generically, $ξ^a$ can only be a rotational Killing field which, furthermore, leaves each marginally trapped 2-sphere cross-section $\mathcal{S}$ of $\mathscr{H}$ invariant. Finally, if $ξ^a$ happens to be hypersurface orthogonal near $\mathscr{H}$, then, not o…

Lorentz violation signatures in the low-energy sector of Ho\v{r}ava gravity from black hole shadow observations
Wentao Liu, Hongxia Huang, Di Wu, Jieci Wang
https://arxiv.org/abs/2506.13504

Lorentz violation signatures in the low-energy sector of Hořava gravity from black hole shadow observations
In this paper, we use the Hořava gravity model and EHT observations of supermassive black holes (BHs) to investigate signatures of Lorentz violation in real astrophysical environments. The Lorentz violation in the rotating Hořava BH spacetime are confined to the strong gravitational field region, being induced by the BH's rotation. Due to the non-separability of the photon motion equations in this spacetime, we employed a numerical backward ray-tracing method to generate shadow images for var…

A viable wormhole model in a five-dimensional spacetime
Peter K. F. Kuhfittig
https://arxiv.org/abs/2506.09111 https://arxiv.org/pdf/…

A viable wormhole model in a five-dimensional spacetime
This paper generalizes two of the author's earlier wormhole solutions that are characterized by an extra spatial dimension. This paper adds the assumption that the components of the line element are functions not only of the radial coordinate $r$ but of the extra coordinate $l$ as well, resulting in a significant generalization. It is shown that the throat of the wormhole can be threaded with ordinary matter and that the unavoidable violation of the null energy condition can be attributed to th…

DSR-relativistic spacetime picture and the phenomenology of Planck-scale-modified time dilation
Giovanni Amelino-Camelia, Giulia Gubitosi, Pietro Pellecchia, Marco Refuto, Giacomo Rosati
https://arxiv.org/abs/2506.08111

DSR-relativistic spacetime picture and the phenomenology of Planck-scale-modified time dilation
The most active area of research in quantum-gravity phenomenology investigates the possibility of Planck-scale-modified dispersion relations, focusing mainly on two alternative scenarios: the "LIV" scenario, characterized by a specific mechanism of breakdown of relativistic symmetries, and the "DSR" scenario, which preserves overall relativistic invariance but with deformed laws of relativistic transformation. Two recent studies of modified dispersion relations, one relying on Finsler geometry …

Non-oscillatory gravitational quasinormal modes of Reissner-Nordstr\"om-de Sitter spacetime
Z. Stuchl\'ik, A. Zhidenko
https://arxiv.org/abs/2506.09829

Non-oscillatory gravitational quasinormal modes of Reissner-Nordström-de Sitter spacetime
Proper oscillation frequencies of black holes (quasinormal modes) of asymptotically de Sitter black holes were extensively studied, yet the non-oscillatory (purely imaginary) branch of modes of gravitational perturbations of the four-dimensional Reissner-Nordström-de Sitter solution was omitted in the literature. This branch of modes appears as deformations of the modes of empty de Sitter space. Here we find accurate numerical values of this branch of quasinormal modes and show that they are r…

Precision predictions of Starobinsky inflation with self-consistent Weyl-squared corrections
Eugenio Bianchi, Mauricio Gamonal
https://arxiv.org/abs/2506.10081

Precision predictions of Starobinsky inflation with self-consistent Weyl-squared corrections
Starobinsky's $R+αR^2$ inflation provides a compelling one-parameter inflationary model that is supported by current cosmological observations. However, at the same order in spacetime derivatives as the $R^2$ term, an effective theory of spacetime geometry must also include the Weyl-squared curvature invariant $W^2$. In this paper, we study the inflationary predictions of the gravitational theory with action of the form $R+αR^2 - βW^2$, where the coupling constant $α$ sets the scale of infl…

Asymptotia of Kerr-de Sitter Black Holes
Samuel Blitz, Jaros{\l}aw Kopi\'nski
https://arxiv.org/abs/2506.18169 https://arxiv.org/…

Asymptotia of Kerr-de Sitter Black Holes
Exterior geometries of physical black holes are believed to asymptotically approach the Kerr--de Sitter spacetime at late times. A characteristic feature of that vacuum Einstein solution is the presence of a hidden symmetry generated by a closed conformal Killing--Yano tensor. Using this symmetry and modern conformal geometry technology, we find necessary conditions for generic solutions to asymptotically approach the Kerr--de Sitter metric. Further, we constrain the admissible form of the geom…

A discussion on the symmetry of relativistic Vlasov gas and its accretion in Kerr-Newman black hole
Yong-qiang Liu
https://arxiv.org/abs/2506.08341 https:/…

A discussion on the symmetry of relativistic Vlasov gas and its accretion in Kerr-Newman black hole
We investigate the kinetic properties of collisionless Vlasov gas in Kerr-Newman spacetime, focusing on how spacetime symmetries constrain the distribution functions. By establishing the general relationship between distribution functions and constants of motion (mass $m$, energy $E$, angular momentum $L_z$, Carter constant $L$) along with $L$'s conjugate configuration variable $Q^{3}$, we derive the analytical framework for particle dynamics in stationary axisymmetric spacetimes. Within the Lo…

Replaced article(s) found for gr-qc. https://arxiv.org/list/gr-qc/new
[2/2]:
- Effect of spacetime geometry on neutrino oscillations
Riya Barick, Indrajit Ghose, Amitabha Lahiri

Theories of the gravity gauge type in de Sitter space
Julian Lang, Yasha Neiman
https://arxiv.org/abs/2506.16707 https://arxiv.org/pd…

Theories of the gravity+gauge type in de Sitter space
We study theories of the "General Relativity + Yang-Mills" type in 4d spacetime with cosmological constant, focusing on formulations where the basic variables are connections and curvatures (but no metric). We present a new Lagrangian for GR coupled to Yang-Mills, which uses the same kind of variables for both sectors, and has a manifest double-copy structure. This Lagrangian comes in both non-chiral (real) and chiral (complex) versions. The chiral version makes it easy to isolate the self-dual…

Greybody factors of charged black holes with axion hair
Ratchaphat Nakarachinda, Petarpa Boonserm, Antonio De Felice, Shinji Tsujikawa, Pitayuth Wongjun
https://arxiv.org/abs/2506.18241

Greybody factors of charged black holes with axion hair
We study the greybody factor of charged hairy black holes (BHs) that arise due to the presence of an axion coupled to the electromagnetic field. Specifically, we consider spin-0 and spin-1 test particles propagating in the background of BHs with axion hair, where the spacetime geometry is modified compared to that of the Reissner-Nordstrom (RN) BH. In contrast to the RN solution, with a given total BH charge, the effective potential for test particles depends on the ratio of electric to magneti…

Universality on thermodynamic relation with corrections in Einstein-Bel-Robinson gravity Black hole
Hai-Long Zhen, Huai-Fan Li, Yu-Bo Ma
https://arxiv.org/abs/2506.08466

Universality on thermodynamic relation with corrections in Einstein-Bel-Robinson gravity Black hole
The generalized thermodynamic extremum relation, as proposed by Goon and Penco, establishes a novel theoretical framework for the study of spacetime thermodynamics. However, extant investigations generally assume that the black hole state parameter is solely a first-order function of the perturbation parameter when exploring the Goon-Penco relation in diverse spacetime contexts. An analytic expression for the perturbation parameter as a function of the black hole entropy can be expressed by tre…

Weak null singularity for the Einstein-Euler system
Yuefeng Song
https://arxiv.org/abs/2506.16635 https://arxiv.org/pdf/2506.16635

Weak null singularity for the Einstein-Euler system
We study the behavior of a self-gravitating perfect relativistic fluid satisfying the Einstein-Euler system in the presence of a weak null terminal spacetime singularity. This type of singularities is expected in the interior of generic dynamical black holes. In the vacuum case, weak null singularities have been constructed locally by Luk, where the metrics extend continuously to the singularities while the Christoffel symbols fail to be square integrable in any neighborhood of any point on the…

From Barthel Randers Kropina Geometries to the Accelerating Universe: A Brief Review of Recent Advances in Finslerian Cosmology
Amine Bouali, Himanshu Chaudhary, Lehel Csillag, Rattanasak Hama, Tiberiu Harko, Sorin V. Sabau, Shahab Shahidi
https://arxiv.org/abs/2506.18422

From Barthel Randers Kropina Geometries to the Accelerating Universe: A Brief Review of Recent Advances in Finslerian Cosmology
We review recent developments in cosmological models based on Finsler geometry and extensions of general relativity within this framework. Finsler geometry generalizes Riemannian geometry by allowing the metric tensor to depend on position and an additional internal degree of freedom, typically represented by a vector field at each point of the spacetime manifold. We explore whether Finsler-type geometries can describe gravitational interaction and cosmological dynamics. In particular, we exami…