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Conformal diagrams for stationary and dynamical strong-field hyperboloidal slices Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-16 Alex Vañó-Viñuales
Conformal Carter–Penrose diagrams are used for the visualization of hyperboloidal slices, which are smooth spacelike slices reaching null infinity. The focus is on the Schwarzschild black hole geometry in spherical symmetry, whose Penrose diagrams are introduced in a pedagogical way. The stationary regime involves time-independent slices. In this case, different options are given for integrating the
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The evaluation for plasma noise in arbitrary time-delay interferometry combinations Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-12 Xin-Lei Zhao, Pan-Pan Wang, Cheng-Gang Shao
The laser interferometer space antenna (LISA) uses laser interferometry to measure gravitational wave-induced distance changes between freely falling test masses on separate spacecraft. In practice, the space-borne gravitational wave detector operates in a plasma medium, and subsequently, the variations in electron density affect the refractive index and add displacement noise to measurements. Geometric
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A covariant tapestry of linear GUP, metric-affine gravity, their Poincaré algebra and entropy bound Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-12 Ahmed Farag Ali, Aneta Wojnar
Motivated by the potential connection between metric-affine gravity and linear generalized uncertainty principle (GUP) in the phase space, we develop a covariant form of linear GUP and an associated modified Poincaré algebra, which exhibits distinctive behavior, nearing nullity at the minimal length scale proposed by linear GUP. We use three-torus geometry to visually represent linear GUP within a
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Gravitational waves with dark matter minispikes: Fourier-domain waveforms of eccentric intermediate-mass-ratio-inspirals Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-09 Xiao-Jun Yue, Zhoujian Cao
An intermediate mass black hole (IMBH) may have a dark matter (DM) minihalo around it and develop a spiky structure called DM minispike. Gravitational waves (GWs) can be produced if a stellar compact object, such as a black hole or neutron star, inspirals into the IMBH. This kind of systems are known as intermediate-mass-ratio-inspirals (IMRIs) and may be observed by space-based GW detectors including
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Dynamical de Sitter black holes in a quasi-stationary expansion Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-09 Aaron Beyen, Efe Hamamcı, Kasper Meerts, Dieter Van den Bleeken
We revisit and improve the analytic study (Gregory et al 2018 Class. Quantum. Grav. 35 155008) of spherically symmetric but dynamical black holes in Einstein’s gravity coupled to a real scalar field. We introduce a series expansion in a small parameter ε that implements slow time dependence. At the leading order (LO), the generic solution is a quasi-stationary Schwarzschild–de Sitter (SdS) metric,
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GYOTO 2.0: a polarized relativistic ray-tracing code Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-05 N Aimar, T Paumard, F H Vincent, E Gourgoulhon, G Perrin
Polarized general-relativistic radiative transfer in the vicinity of black holes and other compact objects has become a crucial tool for probing the properties of relativistic astrophysics plasmas. Instruments like GRAVITY, the Event Horizon telescope, Atacama Large Millimeter/submillimeter Array, or Imaging x-ray Polarimetry Explorer make it very timely to develop such numerical frameworks. In this
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Analyzing warp drive spacetimes with Warp Factory Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-05 Christopher Helmerich, Jared Fuchs, Alexey Bobrick, Luke Sellers, Brandon Melcher, Gianni Martire
The field of warp research has been dominated by analytical methods to investigate potential solutions. However, these approaches often favor simple metric forms that facilitate analysis but ultimately limit the range of exploration of novel solutions. So far the proposed solutions have been unphysical, requiring energy condition violations and large energy requirements. To overcome the analytical
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Emergent modified gravity Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-04 Martin Bojowald, Erick I Duque
A complete canonical formulation of general covariance makes it possible to construct new modified theories of gravity that are not of higher-curvature form, as shown here in a spherically symmetric setting. The usual uniqueness theorems are evaded by using a crucial and novel ingredient, allowing for fundamental fields of gravity distinct from an emergent space-time metric that provides a geometrical
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Dynamical analysis of coupled curvature-matter scenario in viable f(R) dark energy models at de Sitter phase Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-03 Anirban Chatterjee
We explore the interaction between dark matter and curvature-driven dark energy within viable f(R) gravity models, employing the phase-space analysis approach of linear stability theory. By incorporating an interacting term, denoted as Q=αHρ~m(κ23H2ρcurv+1) , into the continuity equations of both sectors, we examine dynamics of two f(R) gravity models that adhere to local gravity constraints and fulfill
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Breaking the cosmological principle into pieces: a prelude to the intrinsically homogeneous and isotropic spacetimes Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-03 L G Gomes
In this manuscript, we show that there are three fundamental building blocks supporting the cosmological principle. The first of them states that there is a special frame in the Universe where the spatial geometry is intrinsically homogeneous and isotropic. The second demands the existence of a fiducial observer to whom the Hubble parameter is isotropic. The last piece states that matter and radiation
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Towards a quantum field theory description of nonlocal spacetime defects Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-03 Christopher D Carone, Noah L Donald
We propose an ansatz for encoding the physics of nonlocal spacetime defects in the Green’s functions for a scalar field theory defined on a causal set. This allows us to numerically study the effects of nonlocal spacetime defects on the discrete Feynman propagator of the theory defined on the causal set in 1+1 dimensions, and to compare to the defect-free limit. The latter approaches the expected continuum
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Adaptive mesh refinement in binary black holes simulations Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-03 Alireza Rashti, Maitraya Bhattacharyya, David Radice, Boris Daszuta, William Cook, Sebastiano Bernuzzi
We discuss refinement criteria for the Berger–Rigoutsos (block-based) refinement algorithm in our numerical relativity code GR-Athena++ in the context of binary black hole (BBH) merger simulations. We compare three different strategies: the ‘box-in-box’ approach, the ‘sphere-in-sphere’ approach and a local criterion for refinement based on the estimation of truncation error of the finite difference
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Gravitational waves in the circular restricted three body problem Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-03 Mikel Martin Barandiaran, Sachiko Kuroyanagi, Savvas Nesseris
The prospect of unprecedented high-quality data of gravitational waves in the upcoming decades demands a theoretical effort to optimally study and analyze the signals that next generation detectors will provide. Here we study the gravitational wave emission and related dynamics during the inspiralling phase of the Circular Restricted Three Body Problem, a modification of the conventional binary scenario
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Non-stoichiometric silicon nitride for future gravitational wave detectors Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-02 G S Wallace, M Ben Yaala, S C Tait, G Vajente, T McCanny, C Clark, D Gibson, J Hough, I W Martin, S Rowan, S Reid
Silicon nitride thin films were deposited at room temperature employing a custom ion beam deposition (IBD) system. The stoichiometry of these films was tuned by controlling the nitrogen gas flow through the ion source and a process gas ring. A correlation is established between the process parameters, such as ion beam voltage and ion current, and the optical and mechanical properties of the films based
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Quasinormal modes of Reissner–Nordström–AdS: the approach to extremality Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-02 Filip Ficek, Claude Warnick
We consider the quasinormal spectrum of scalar and axial perturbations of the Reissner–Nordström–AdS black hole as the horizon approaches extremality. By considering a foliation of the black hole by spacelike surfaces which intersect the future horizon we implement numerical methods which are well behaved up to and including the extremal limit and which admit initial data which is nontrivial at the
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Bayesian real-time classification of multi-messenger electromagnetic and gravitational-wave observations Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-02 Marina Berbel, Miquel Miravet-Tenés, Sushant Sharma Chaudhary, Simone Albanesi, Marco Cavaglià, Lorena Magaña Zertuche, Dimitra Tseneklidou, Yanyan Zheng, Michael W Coughlin, Andrew Toivonen
Because of the electromagnetic (EM) radiation produced during the merger, compact binary coalescences with neutron stars may result in multi-messenger observations. In order to follow up on the gravitational-wave (GW) signal with EM telescopes, it is critical to promptly identify the properties of these sources. This identification must rely on the properties of the progenitor source, such as the component
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Linear graviton as a quantum particle Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-02 Maciej Przanowski, Michał Dobrski, Jaromir Tosiek, Francisco J Turrubiates
Wave function of a single linear graviton and its interpretation are proposed. The evolution equation for this function is given. A Hermitian operator with mutually commuting components canonically conjugated to the momentum operator of the linear graviton is found. Second quantization of the linear graviton quantum mechanics as well as quantization of the classical free linear graviton field are investigated
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Equivalence principle for quantum mechanics in the Heisenberg picture Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-02 Otto C W Kong
We present an exact quantum observable analog of the weak equivalence principle for a ‘relativistic’ quantum particle. The quantum geodesic equations are obtained from Heisenberg equations of motion as an exact analog of a fully covariant classical Hamiltonian evolution picture, with the proper identification of the canonical momentum variables as p µ , rather than p µ . We discuss the meaning of the
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A note on no-hair properties of static black holes in four and higher dimensional spacetimes with cosmological constant Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-28 Akihiro Ishibashi, Satoshi Matsumoto, Yuichiro Yoneo
We study no-hair properties of static black holes in four and higher dimensional spacetimes with a cosmological constant. For the vanishing cosmological constant case, we show a no-hair theorem and also a no-short-hair theorem under certain conditions for the energy-momentum of matter fields. For the positive cosmological constant case, we discuss conditions for hairy static black holes to exist in
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Phenomenology of axionic static neutron stars with masses in the mass-gap region Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-27 V K Oikonomou
In this work we consider an axionic scalar-tensor theory of gravity and its effects on static neutron stars (NSs). The axionic theory is considered in the regime in which the axion oscillates around its potential minimum, which cosmologically occurs post-inflationary, when the Hubble rate is of the same order as the axion mass. We construct the Tolman–Oppenheimer–Volkoff equations for this axionic
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Unimodular Plebański gravity Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-27 Steffen Gielen, Elliot Nash
We present new action principles for unimodular gravity, defined in the chiral Plebański formulation based on (complex) two-forms and a complex SO(3) connection. In these theories, just as in their analogues in the metric formulation, the cosmological constant does not take a prescribed value but is an integration constant whose value can differ between different (classical) solutions. We discuss some
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GSpyNetTree: a signal-vs-glitch classifier for gravitational-wave event candidates Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-26 Sofía Álvarez-López, Annudesh Liyanage, Julian Ding, Raymond Ng, Jess McIver
Despite achieving sensitivities capable of detecting the extremely small amplitude of gravitational waves (GWs), LIGO and Virgo detector data contain frequent bursts of non-Gaussian transient noise, commonly known as ‘glitches’. Glitches come in various time-frequency morphologies, and they are particularly challenging when they mimic the form of real GWs. Given the higher expected event rate in the
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Anti-de Sitter momentum space in 3D and 4D quantum gravity Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-25 Giovanni Amelino-Camelia, Iarley P Lobo, Giovanni Palmisano
There has been strong interest in the possibility that in the quantum-gravity realm momentum space might be curved, mainly focusing, especially for what concerns phenomenological implications, on the case of a de Sitter momentum space. We here take as starting point the known fact that quantum gravity coupled to matter in 2+1 spacetime dimensions gives rise to an effective picture characterized by
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Mode stability for gravitational instantons of type D Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-22 Gustav Nilsson
We study Ricci-flat perturbations of gravitational instantons of Petrov type D. Analogously to the Lorentzian case, the Weyl curvature scalars of extreme spin weight satisfy a Riemannian version of the separable Teukolsky equation. As a step toward infinitesimal rigidity of the type D Kerr and Taub-bolt families of instantons, we prove mode stability, i.e. that the Teukolsky equation admits no solutions
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Solutions with pure radiation and gyratons in 3D massive gravity theories Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-22 Ercan Kilicarslan, Ivan Kolář
We find exact solutions of topologically massive gravity (TMG) and new massive gravity (NMG) in 2 + 1 dimensions (3D) with an arbitrary cosmological constant, pure radiation, and gyratons, i.e. with possibly non-zero T uu and T ux in canonical coordinates. Since any ‘reasonable’ geometry in 3D (i.e. admitting a null geodesic congruence) is either expanding Robinson–Trautman ( Θ≠0 ) or Kundt ( Θ=0 )
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Black holes, conformal symmetry, and fundamental fields Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-19 José Navarro-Salas
Cosmic censorship protects the outside world from black hole singularities and paves the way for assigning entropy to gravity at the event horizons. We point out a tension between cosmic censorship and the quantum backreacted geometry of Schwarzschild black holes, induced by vacuum polarization and driven by the conformal anomaly. A similar tension appears for the Weyl curvature hypothesis at the Big
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Bulk viscous late acceleration under near equilibrium conditions in f(R, T) gravity with mixed dark matter Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-19 Vishnu A Pai, Titus K Mathew
Numerous studies have tried to explain the observed late acceleration of the Universe as being caused by the bulk viscosity associated with the dark matter (DM) component. However, for driving the said accelerated expansion, all such models require a violation of near equilibrium conditions (NECs) associated with the background viscous theory. But recently, it was found that, with the aid of a cosmological
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An approximate application of quantum gravity to the rotation problem Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-19 R Michael Jones
Arbitrary initial conditions allow solutions of Einstein’s field equations for General Relativity to have arbitrarily large relative rotation of matter and inertial frames. The ‘Rotation Problem’ is to explain why the measured relative rotation rate is so small. As it turns out, nearly any reasonable theory of quantum gravity can solve the rotation problem by phase interference. Even as early as about
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The Synge G-Method: cosmology, wormholes, firewalls, geometry Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-15 G F R Ellis, D Garfinkle
Unphysical equations of state result from the unrestricted use of the Synge G-trick of running the Einstein field equations backwards; in particular often this results in ρ+p<0 which implies negative inertial mass density, which does not occur in reality. This is the basis of some unphysical spacetime models including phantom energy in cosmology and traversable wormholes. The slogan ‘ER = EPR’ appears
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Affine linking number estimates for the number of times an observer sees a star Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-15 Vladimir Chernov, Ryan Maguire
Affine linking numbers are the generalization of linking numbers to the case of nonzero homologous linked submanifolds. They were introduced by Rudyak and the first author who used them to study causality in globally hyperbolic spacetimes.In this paper we use affine linking numbers to estimate the number of times an observer sees light from a star, that is how many copies of the star do they see on
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Testing alternative spacetimes by high-frequency quasi-periodic oscillations observed in microquasars and active galactic nuclei Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-15 Misbah Shahzadi, Martin Kološ, Rabia Saleem, Zdeněk Stuchlík
In this article, we try to capture the influence of deviation from standard Kerr black hole (BH) spacetime on observed high-frequency quasi-periodic oscillations (QPOs) signal. We explore the dynamics of test particles in the field of rotating compact objects governed by the various modifications of the standard Kerr BH spacetime and apply the model of epicyclic oscillations of Keplerian discs to the
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Quantum matter and gravitation: photons in a waveguide Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-15 Victor Atanasov, Avadh Saxena
The conditions required by quantum matter to modify space-time geometry are explored within the framework of the general theory of relativity. The required characteristics for space-time modification in solid state structures, are met in either (a) massive photon Bose–Einstein condensate in a waveguide, or (b) the massive photons in superconductor’s bulk, or (c) the Bose–Einstein condensate of acoustic
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Consistency of Lorentz-invariance violation neutrino scenarios in time delay analyses Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-14 J M Carmona, J L Cortés, M A Reyes
Modifications inspired by quantum gravity in the kinematics of special relativity can manifest in various ways, including anomalies in the time of flight of massless particles and the emergence of decay channels for otherwise stable particles. Typically, these effects are studied independently; however, it may be necessary to combine both to perform a consistent analysis. In this work, we study the
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Dark matter effects explanation with the torsion in the Minkowski space Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-14 Petro Romanets
Investigating rotation curves and the Tully–Fisher ratio within galaxies represents a central theme of extensive research and scientific interest. Despite several theoretical models, a comprehensive explanation of the observed correlation between galaxy types and their rotation curves remains elusive. This study endeavors to bridge this knowledge gap by delving into the discernible connection between
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Revisiting loop quantum gravity with selfdual variables: Hilbert space and first reality condition Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-13 Hanno Sahlmann, Robert Seeger
We consider the quantization of gravity as an SL(2,C) gauge theory in terms of Ashtekar’s selfdual variables and reality conditions for the spatial metric (RCI) and its evolution (RCII). We start from a holomorphic phase space formulation. It is then natural to push for a quantization in terms of holomorphic wave functions. Thus we consider holomorphic cylindrical wave functions over SL(2,C) connections
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Revisiting loop quantum gravity with selfdual variables: classical theory Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-12 Hanno Sahlmann, Robert Seeger
We review the classical formulation of general relativity as an SL(2,C) gauge theory in terms of Ashtekar’s self-dual variables and reality conditions for the spatial metric (first reality condition) and its evolution (second reality condition), and we add some new observations and results. We first explain in detail how a connection taking values in the Lie algebra of the complex Lorentz group yields
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Gravitational repulsion in an expanding ball of dust Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-12 Diogo P L Bragança
In general relativity, there is a velocity dependent term in the gravitational acceleration of a test particle for an observer at infinity. Depending on the direction of motion and the speed, that term can be repulsive. We show that this is also the case in the Parametrized Post-Newtonian (PPN) formalism. We compute the magnitude of that repulsive term for an expanding sphere of dust observed at infinity
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Creation of fermions in a two-dimensional de Sitter space via a quantum gravity approach Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-12 M Salti, O Aydogdu, K Sogut
We discuss the production process of Dirac particles in a two-dimensional de Sitter geometry via the framework of rainbow gravity from the general relativity and the teleparallel theory perspectives. On this purpose, we find out the exact analytical solutions for the selected space-time model and then conclude that the general relativity and the teleparallel theory versions of the covariant Dirac equation
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The weak gravity conjecture, overcharged shells and gravitational traps Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-08 Alex Kehagias, Kostas D Kokkotas, Antonio Riotto, John Taskas, George Tringas
The Weak Gravity Conjecture (WGC) predicts that in quantum gravity there should exist overcharged states, that is states with charge larger than their mass. Extending this to large masses and charges, we are expecting similar overcharged classical solutions. This has been demonstrated in higher-derivative extensions of General Relativity. In this paper we investigate the existence of overcharged solutions
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Spherically symmetric elastic bodies in general relativity Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-08 Artur Alho, José Natário, Paolo Pani, Guilherme Raposo
The purpose of this review it to present a renewed perspective of the problem of self-gravitating elastic bodies under spherical symmetry. It is also a companion to the papers (2022 Phys. Rev. D 105 044025, 2022 Phys. Rev. D 106 L041502) and (arXiv:2306.16584 [gr-qc]), where we introduced a new definition of spherically symmetric elastic bodies in general relativity, and applied it to investigate the
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Universality of the quantum energy flux at the inner horizon of asymptotically de Sitter black holes Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-07 Peter Hintz, Christiane K M Klein
Recently, it was found that the energy flux of a free scalar quantum field on a Reissner–Nordström–de Sitter spacetime has a quadratic divergence towards the inner horizon of the black hole. Moreover, the leading divergence was found to be state independent as long as the spectral gap of the wave equation on the spacetime is sufficiently large. In this work, we show that the latter result can be extended
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A torsion balance as a weak-force testbed for novel optical inertial sensors Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-05 Gerald Bergmann, Carolin Cordes, Christoph Gentemann, Vitus Händchen, Wang Qinglan, Hao Yan, Karsten Danzmann, Gerhard Heinzel, Moritz Mehmet
Torsion balances (TBs) are versatile instruments known for their ability to measure tiny forces and accelerations with high precision. We are currently commissioning a new TB facility to support the development and testing of novel optical inertial sensor units for future gravity-related space missions. Here, we report on the status of our apparatus and present first sensitivity curves that demonstrate
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Extracting electromagnetic signatures of spacetime fluctuations Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-01 B Sharmila, Sander M Vermeulen, Animesh Datta
We present a formalism to discern the effects of fluctuations of the spacetime metric on electromagnetic radiation. The formalism works via the measurement of electromagnetic field correlations, while allowing a clear assessment of the assumptions involved. As an application of the formalism, we present a model of spacetime fluctuations that appear as random fluctuations of the refractive index of
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Stationary solutions of the axially symmetric Einstein–Vlasov system: present status and open problems Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-01 Ellery Ames, Håkan Andréasson
The purpose of this work is to review the status about stationary solutions of the axially symmetric Einstein–Vlasov system with a focus on open problems of both analytical and numerical nature. For the latter we emphasize that the code used to construct stationary solutions in Ames et al (2016 Class. Quantum Grav. 33 155008; 2019 Phys. Rev. D 99 024012) is open source, see Ames and Logg (2023 J. Open
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Constraining the graviton mass with the NANOGrav 15 year data set Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-01 Yu-Mei Wu, Zu-Cheng Chen, Yan-Chen Bi, Qing-Guo Huang
The recently detected stochastic signal by several pulsar timing array collaborations, offers an opportunity to scrutinize the fundamental properties of gravity, including the potential mass of the graviton. In this study, we analyze the North American Nanohertz Observatory for Gravitational Waves 15 year data set to search for a stochastic gravitational wave background with modified Hellings–Downs
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The mass gap in five dimensional Einstein–Gauss–Bonnet black holes: a geometrical explanation Classical Quant. Grav. (IF 3.5) Pub Date : 2024-03-01 C Hansraj, R Goswami, S D Maharaj
It is well known that, unlike in higher dimensional general relativity (GR), we cannot have a black hole with an arbitrarily small mass in five dimensional Einstein–Gauss–Bonnet gravity. When we study the dynamical black hole formation via the radiation collapse in the radiating Boulware–Deser spacetime in five dimensions, the central zero mass singularity is weak, conical and naked, and the horizon
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Spinor fields, CPTM symmetry and smallness of cosmological constant in framework of extended manifold Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-26 S Bondarenko, V De La Hoz-Coronell
A model of an extended manifold for the Dirac spinor field is considered. Two Lagrangians related by charge-parity-time-mass symmetry are constructed for a pair of the Dirac spinor fields with each spinor field defined in a separate manifold. An interaction between the matter fields in the manifolds is introduced through gravity. A fermionic effective action of the general system is constructed and
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Mach’s principle-based model of the origin of mass Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-23 Yu-Jie Chen, Yuan-Yuan Liu, Yu-Zhu Chen, Wen-Du Li, Wu-Sheng Dai
In this paper, we present a Mach’s principle-based model of the origin of mass. According to Mach’s principle, the mass of matter arises from the coupling with the rest of the Universe rather than being an inherent property of matter itself. This model, in a sense, provides a model realization of Mach’s principle. In this model, the mass of matter is determined by spacetime. We illustrate the model
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The radiant massive magnetic dipole Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-21 José Diaz Polanco, José Ayala Hoffmann, Maximiliano Ujevic
We present an exact, time-dependent solution for the Einstein field equations that models the coupling between an anisotropic fluid and a magnetic field in an axially symmetric space-time. By carefully selecting the metric components, we achieve a convenient separation of variables that enables us to solve Einstein’s field equations and obtain a solution that evolves into the Gutsunaev–Manko massive
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Robinson–Trautman solutions with scalar hair and Ricci flow Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-21 Masato Nozawa, Takashi Torii
The vacuum Robinson–Trautman solution admits a shear-free and twist-free null geodesic congruence with a nonvanishing expansion. We perform a comprehensive classification of solutions exhibiting this property in Einstein’s gravity with a massless scalar field, assuming that the solution belongs at least to Petrov-type II and some of the components of Ricci tensor identically vanish. We find that these
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The scattering map on collapsing charged spherically symmetric spacetimes Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-20 Fred Alford
In this paper we generalise our previous results (Alford 2020 Ann. Inst. Henri Poincare 21 2031–92) concerning scattering on the exterior of collapsing dust clouds to the charged case, including in particular the extremal case. We analyse the energy boundedness of solutions φ to the wave equation on the exterior of collapsing spherically symmetric charged matter clouds. We then proceed to define the
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Scalar-multi-tensor approach to fT,B,∇μT,∇μB teleparallel gravity Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-16 E M B Assencio, P J Pompeia
In this work we analyze, in the context of modified teleparallel gravity, the equivalence between scalar-vector-tensor theories and geometrical theories of the type fT,B,∇μT,∇μB , where T and B are respectively the scalar torsion and the boundary scalar. This analysis is performed in the Jordan and Einstein frames. In particular, in the latter frame, two distinct cases are analyzed, where the role
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Nested solutions of gravitational condensate stars Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-15 Daniel Jampolski, Luciano Rezzolla
Black holes are normally and naturally associated to the end-point of gravitational collapse. Yet, alternatives have been proposed and a particularly interesting one is that of gravitational condensate stars, or gravastars. We here revisit the gravastar model and increase the degree of speculation by considering new solutions that are inspired by the original model of gravastars with anisotropic pressure
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General-relativistic wave–particle duality with torsion Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-14 Francisco Ribeiro Benard Guedes, Nikodem Janusz Popławski
We propose that the four-velocity of a Dirac particle is related to its relativistic wave function by ui=ψˉγiψ/ψˉψ . This relativistic wave–particle duality relation is demonstrated for a free particle related to a plane wave in a flat spacetime. For a curved spacetime with torsion, the momentum four-vector of a spinor is related to a generator of translation, given by a covariant derivative. The spin
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On the space of compact diamonds of Lorentzian length spaces Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-14 Waldemar Barrera, Luis Montes de Oca, Didier A Solis
In this work we introduce the taxicab and uniform products for Lorentzian pre-length spaces. We further use these concepts to endow the space D(R×TX) of causal diamonds with a Lorentzian length space structure, closely relating its causal properties with its geometry as a metric space furnished with its associated Hausdorff distance. Among the general results, we show that this space is geodesic and
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Laser frequency stabilization with the use of homodyne quadrature interferometers Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-13 C Di Fronzo, N A Holland, A L Mitchell, S J Cooper, M Valentini, D Martynov, L Prokhorov, C M Mow-Lowry
Laser frequency stabilization is a crucial technique for precision metrology. We demonstrate laser frequency control using a compact, interferometric sensor, specially modified for sensitivity to laser frequency noise. This setup achieves a balance between compact size, ease of use, and affordability. We stabilize the laser frequency noise, of a low-cost solid-state laser, to 4.5 kHz Hz−1 at 1 Hz
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Tilt-to-length coupling noise suppression based on transformation of q parameters of Gaussian beams in spaceborne gravitational wave detection Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-13 Jinsong Liu, Xin Xu, Yidong Tan
Suppression of the coupling of unavoidable angular spacecraft jitter into the longitudinal displacement measurement, known as tilt-to-length (TTL) coupling, is crucial for realizing the required sensitivity of picometer /Hz1/2 level within the frequency range of 1 mHz–1 Hz in spaceborne gravitational wave detection. In this paper, we propose a novel method to suppress the TTL coupling between two Gaussian
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Thermodynamics and optical properties of phantom AdS black holes in massive gravity Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-13 Kh Jafarzade, B Eslam Panah, M E Rodrigues
Motivated by high interest in Lorentz invariant massive gravity models known as dRGT massive gravity, we present an exact phantom black hole solution in this theory of gravity and discuss the thermodynamic structure of the black hole in the canonical ensemble. Calculating the conserved and thermodynamic quantities, we check the validity of the first law of thermodynamics and the Smarr relation in the
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Implication of nano-Hertz stochastic gravitational wave on dynamical dark matter through a dark first-order phase transition Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-13 Siyu Jiang, Aidi Yang, Jiucheng Ma, Fa Peng Huang
For the first time, the expected stochastic gravitational wave background is probably discovered after observing the Hellings Downs correlation curve by several pulsar timing array (PTA) collaborations around the globe including NANOGrav, European PTA, Parkes PTA, and Chinese PTA. These new observations can help to explore or constrain the dark matter (DM) formation mechanisms in the early Universe
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Scattering amplitudes for self-force Classical Quant. Grav. (IF 3.5) Pub Date : 2024-02-12 Tim Adamo, Andrea Cristofoli, Anton Ilderton, Sonja Klisch
The self-force expansion allows the study of deviations from geodesic motion due to the emission of radiation and its consequent back-reaction. We investigate this scheme within the on-shell framework of semiclassical scattering amplitudes for particles emitting photons or gravitons on a static, spherically symmetric background. We first present the exact scalar two-point amplitudes for Coulomb and