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Suppression of spacetime singularities in quantum gravity Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-15 Johanna N Borissova
We investigate the requirement of suppressing spacetime geometries with a curvature singularity via destructive interference in the Lorentzian gravitational path integral as a constraint on the microscopic action for gravity. Based on simple examples of static spherically symmetric spacetimes, we demonstrate that complete singularity suppression in the path integral stipulates that the action for gravity
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Cosmography with next-generation gravitational wave detectors Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-14 Hsin-Yu Chen, Jose María Ezquiaga and Ish Gupta
Advancements in cosmology through next-generation (XG) ground-based gravitational wave (GW) observatories will bring in a paradigm shift. We explore the pivotal role that GW standard sirens will play in inferring cosmological parameters with XG observatories, not only achieving exquisite precision but also opening up unprecedented redshifts. We examine the merits and the systematic biases involved
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A trick for calculating surface gravities of Killing horizons Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-14 Jinbo Yang
We propose a trick for calculating the surface gravity of the Killing horizon, especially for cases of rotating black holes. By choosing nice slices, the surface gravity and angular velocities can be directly read from relevant components of the inverse metric. We give several cases to show how to apply the trick step by step.
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Comment on ‘Index-free heat kernel coefficients’ Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-14 S A Franchino-Viñas
The article by van de Ven (1998 Class. Quantum Grav.15 2311–44), is one of the fundamental references for higher-order heat kernel coefficients in curved backgrounds and with non-Abelian gauge connections. In this manuscript, we point out two errors and ambiguities in the coefficient, which may also affect the higher-order ones.
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Neural network time-series classifiers for gravitational-wave searches in single-detector periods Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-13 A Trovato, E Chassande-Mottin, M Bejger, R Flamary and N Courty
The search for gravitational-wave (GW) signals is limited by non-Gaussian transient noises that mimic astrophysical signals. Temporal coincidence between two or more detectors is used to mitigate contamination by these instrumental glitches. However, when a single detector is in operation, coincidence is impossible, and other strategies have to be used. We explore the possibility of using neural network
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Quick recipes for gravitational-wave selection effects Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-13 Davide Gerosa and Malvina Bellotti
Accurate modeling of selection effects is a key ingredient to the success of gravitational-wave astronomy. The detection probability plays a crucial role in both statistical population studies, where it enters the hierarchical Bayesian likelihood, and astrophysical modeling, where it is used to convert predictions from population-synthesis codes into observable distributions. We review the most commonly
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Thermal defocus-free Hartmann Wavefront Sensors for monitoring aberrations in Advanced Virgo Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-12 Lorenzo Aiello, Pier Paolo Palma, Matteo Lorenzini, Elisabetta Cesarini, Maria Cifaldi, Chiara Di Fronzo, Diana Lumaca, Yury Minenkov, Ilaria Nardecchia, Alessio Rocchi, Claudia Taranto and Viviana Fafone
Earth-based gravitational waves interferometric detectors are shot-noise limited in the high-frequency region of their sensitivity band. While enhancing the laser input power is the natural solution to improve on the shot noise limit, higher power also increases the optical aberration budget due to the laser absorption in the highly reflective coatings of mirrors, resulting in a drop of the sensitivity
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Ar transport and blister growth kinetics in titania-doped germania-based optical coatings Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-09 Émile Lalande, Aaron Davenport, Lory Marchand, Ashot Markosyan, Daniel Martinez, Annalisa Paolone, Michael Rezac, Marco Bazzan, Martin Chicoine, Julien L Colaux, Matthieu Coulon, Martin M Fejer, Alexandre W Lussier, Ettore Majorana, Ludvik Martinu, Carmen Menoni, Christophe Michel, Fulvio Ricci, François Schiettekatte, Nikita Shcheblanov, Joshua R Smith, Julien Teillon, Guy Terwagne, Gabriele Vajente
Blistering is a phenomenon sometimes observed in sputtered-deposited thin films but seldom investigated in detail. Here, we consider the case of titania-doped germania (TGO)/silica multilayers deposited by ion beam sputtering. TGO is a candidate as high refractive index material in the Bragg mirrors for the next iteration of gravitational waves detectors. It needs to be annealed at 600 ∘C for 100 h
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New Generation of Superattenuator for Einstein Telescope: preliminary studies Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-08 A Bertocco, M Bruno, R De Rosa, L Di Fiore, D D’Urso, F Frasconi, A Gennai, L Lucchesi, M Refat, F Pilo, D Rozza, P Ruggi, V Sipala, I Tosta e Melo, L Trozzo
Seismic noise and local disturbances are dominant noise sources for ground-based gravitational waves detectors in the low frequency region (0.1–10 Hz) limiting their sensitivity and duty cycle. With the introduction of high-performance seismic isolation systems based on mechanical pendula, the 2nd generation laser interferometric detectors have reached the scientific goal of the first direct observation
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Charged rotating BTZ solution revisited: new coordinates and algebraic classifications Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-08 Hideki Maeda, Jiří Podolský
We revisit the charged rotating Bañados–Teitelboim–Zanelli (BTZ) solution in the three-dimensional Einstein–Maxwell-Λ system. After the erroneous announcement of its discovery at the end of the original BTZ paper in 1992, the solution was first obtained by Clément in the paper published in 1996 by coordinate transformations from the charged non-rotating BTZ solution. While Clément’s form of the solution
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On point-ahead angle control strategies for TianQin Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-08 Dezhi Wang, Xuefeng Zhang, Hui-Zong Duan
Pointing-related displacement noises are crucial in space-based gravitational wave detectors, where point-ahead angle control of transmitted laser beams may contribute significantly. For TianQin that features a geocentric concept, the circular high orbit design with a nearly fixed constellation plane gives rise to small variations of the point-ahead angles within ±25 nrad in-plane and ±10 nrad off-plane
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Anisotropic compact star in linear f(Q)-action Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-07 S K Maurya, Abdelghani Errehymy, Gabriel-Eduard Vîlcu, Haifa I Alrebdi, Kottakkaran Sooppy Nisar, Abdel-Haleem Abdel-Aty
In this paper, a significant leap forward in understanding compact stellar systems and the modified f(Q) gravity theory is achieved. The pivotal discovery lies in the successful derivation of an exact solution that fulfils the static geometry and spherical symmetry criteria, permitting the study of compact stellar configurations with an anisotropic fluid. The model is rigorously tested and satisfies
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On the covariant formulation of gauge theories with boundaries Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-07 Mehdi Assanioussi, Jerzy Kowalski-Glikman, Ilkka Mäkinen, Ludovic Varrin
In the present article, we review the classical covariant formulation of Yang–Mills theory and general relativity in the presence of spacetime boundaries, focusing mainly on the derivation of the presymplectic forms and their properties. We further revisit the introduction of the edge modes and the conditions which justify them, in the context where only field-independent gauge transformations are
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Algebraic classification of 2+1 geometries: a new approach Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-07 Matúš Papajčík, Jiří Podolský
We present a convenient method of algebraic classification of 2+1 spacetimes into the types I, II, D, III, N and O, without using any field equations. It is based on the 2+1 analogue of the Newman–Penrose curvature scalars ΨA of distinct boost weights, which are specific projections of the Cotton tensor onto a suitable null triad. The algebraic types are then simply determined by the gradual vanishing
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Does spacetime have memories? Searching for gravitational-wave memory in the third LIGO-Virgo-KAGRA gravitational-wave transient catalogue Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-07 Shun Yin Cheung, Paul D Lasky, Eric Thrane
Gravitational-wave memory is a non-linear effect predicted by general relativity that remains undetected. We apply a Bayesian analysis framework to search for gravitational-wave memory using binary black hole mergers in LIGO-Virgo-KAGRA’s third gravitational-wave transient catalogue. We obtain a Bayes factor of lnBF=0.01 , in favour of the no-memory hypothesis, which implies that we are unable to
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Simulating electromagnetic cascades with Lorentz invariance violation Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-07 Andrey Saveliev, Rafael Alves Batista
Lorentz invariance violation (LIV) is a phenomenon featuring in various quantum gravity models whereby Lorentz symmetry is broken at high energies, potentially impacting the behaviour of particles and their interactions. Here we investigate the phenomenology of LIV within the context of gamma-ray–induced electromagnetic cascades. We conduct detailed numerical simulations to explore the expected manifestations
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How the spherical modes of gravitational waves can be detected despite only seeing one ray Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-07 Alejandro Torres-Orjuela
The spherical modes of gravitational waves (GWs) have become a major focus of recent detection campaigns due to the additional information they can provide about different properties of the source. However, GW detection is restricted to only detecting one ray and hence it is not obvious how we can extract information about angular properties. In this note, we introduce a new gauge that makes visible
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Sagnac-type neutron displacement-noise-free interferometeric gravitational-wave detector Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-07 Yuki Kawasaki, Shoki Iwaguchi, Tomohiro Ishikawa, Atsushi Nishizawa, Masaaki Kitaguchi, Yutaka Yamagata, Yanbei Chen, Bin Wu, Ryuma Shimizu, Kurumi Umemura, Kenji Tsuji, Hirohiko Shimizu, Yuta Michimura, Kazuhiro Kobayashi, Takafumi Onishi, Seiji Kawamura
The detection of low-frequency gravitational waves on Earth requires the reduction of displacement noise, which dominates the low-frequency band. One method to cancel test mass displacement noise is a neutron displacement-noise-free interferometer (DFI). This paper proposes a new neutron DFI configuration, a Sagnac-type neutron DFI, which uses a Sagnac interferometer in place of the Mach–Zehnder interferometer
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Schwinger correlation of Dirac fields in accelerated frames Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-03 Hao-Sheng Zeng, Heng Liu, Lian-Jie Wu
We study the Schwinger correlation of Dirac fields in the noninertial frames under the influences of both constant and pulsed electric fields. We use both the entanglement negativity and quantum mutual information between particle and antiparticle as the indicator of the Schwinger correlation observed by the accelerated observers. We find that the Schwinger correlation in the inertial frames is the
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A realist interpretation of unitarity in quantum gravity Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-03 Indrajit Sen, Stephon Alexander, Justin Dressel
Unitarity is a difficult concept to implement in canonical quantum gravity because of state non-normalisability and the problem of time. We take a realist approach based on pilot-wave theory to address this issue in the Ashtekar formulation of the Wheeler–DeWitt equation. We use the postulate of a definite configuration in the theory to define a global time for the gravitational-fermionic system recently
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Gravitational wave peeps from EMRIs and their implication for LISA signal confusion noise Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-03 Daniel J Oliver, Aaron D Johnson, Joel Berrier, Kostas Glampedakis, Daniel Kennefick
Scattering events around the center of massive galaxies will occasionally toss a stellar-mass compact object into an orbit around the massive black hole (MBH) at the center, beginning an extreme mass ratio inspiral (EMRI). The early stages of such a highly eccentric orbit are not likely to produce detectable gravitational waves (GWs), as the source will only be in a suitable frequency band briefly
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Symmetry and instability of marginally outer trapped surfaces Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-02 Ivan Booth, Graham Cox, Juan Margalef-Bentabol
We consider an initial data set having a continuous symmetry and a marginally outer trapped surface (MOTS) that is not preserved by this symmetry. We show that such a MOTS is unstable except in an exceptional case. In non-rotating cases we provide a Courant-type lower bound on the number of unstable eigenvalues. These results are then used to prove the instability of a large class of exotic MOTSs that
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Worldline path integrals for the graviton Classical Quant. Grav. (IF 3.5) Pub Date : 2024-05-02 Fiorenzo Bastianelli, Mattia Damia Paciarini
We present an extension to arbitrary dimensions of a worldline path integral approach to one-loop quantum gravity, which was previously formulated in four spacetime dimensions. By utilizing this method, we recalculate gauge invariant coefficients related to the UV divergences of quantum gravity. These gauge invariant coefficients were previously obtained in arbitrary dimensions through two alternative
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Constant velocity physical warp drive solution Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-29 Jared Fuchs, Christopher Helmerich, Alexey Bobrick, Luke Sellers, Brandon Melcher, Gianni Martire
Warp drives are exotic solutions of general relativity that offer novel means of transportation. In this study, we present a solution for a constant-velocity subluminal warp drive that satisfies all of the energy conditions. The solution involves combining a stable matter shell with a shift vector distribution that closely matches well-known warp drive solutions such as the Alcubierre metric. We generate
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From minimal strings towards Jackiw–Teitelboim gravity: on their resurgence, resonance, and black holes Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-29 Paolo Gregori, Ricardo Schiappa
Two remarkable facts about Jackiw–Teitelboim (JT) two-dimensional dilaton-gravity have been recently uncovered: this theory is dual to an ensemble of quantum mechanical theories; and such ensembles are described by a random matrix model which itself may be regarded as a special (large matter-central-charge) limit of minimal string theory. This work addresses this limit, putting it in its broader matrix-model
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Spherical warp-based bubble with non–trivial lapse function and its consequences on matter content Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-26 G Abellán, N Bolívar, I Vasilev
In the present work, we study the consequences of including the lapse function as an additional degree of freedom for a general spherical warp-based geometry. By allowing a non-uniform lapse function to evolve, we find that it is possible to accommodate a fluid that includes heat flow. This broadens the range of fluid types that have been studied in these systems and is consistent with the spherical
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Gravitational wave pulse and memory effects for hairy Kiselev black hole and its analogy with Bondi–Sachs formalism Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-21 H Hadi, Amin Rezaei Akbarieh and David F Mota
The investigation of non-vacuum cosmological backgrounds containing black holes is greatly enhanced by the Kiselev solution. This solution plays a crucial role in understanding the properties of the background and its relationship with the features of the black hole. Consequently, the gravitational memory effects at large distances from the black hole offer a valuable means of obtaining information
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Cosmology in Lorentzian Regge calculus: causality violations, massless scalar field and discrete dynamics Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-21 Alexander F Jercher and Sebastian Steinhaus
We develop a model of spatially flat, homogeneous and isotropic cosmology in Lorentzian Regge calculus, employing four-dimensional Lorentzian frusta as building blocks. By examining the causal structure of the discrete spacetimes obtained by gluing such four-frusta in spatial and temporal direction, we find causality violations if the sub-cells connecting spatial slices are spacelike. A Wick rotation
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Unveiling the cation ratio mediated structural modifications in TiO2:GeO2 mixtures for gravitational-wave detectors Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-21 Sangita Bhowmick, Ruth Osovsky, Aaron Davenport, François Schiettekatte, Martin Chicoine and Carmen S Menoni
Amorphous thin films of Ti doped GeO2 are of interest for coatings of the mirrors in gravitational wave detectors (GWDs) due to their low internal friction (Vajente et al 2021 Phys. Rev. Lett.127 071101). The addition of Ti to amorphous GeO2 (a-GeO2) enables tailoring of the optical and structural properties of the mixtures. However, the specific modifications that occur in the amorphous network with
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Generalized K-essence inflation in Jordan and Einstein frames Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-21 Orlando Luongo and Tommaso Mengoni
We here explore a generalized K-essence model which exhibits characteristics akin to ordinary matter. The inflationary framework proposed aims to unify old with chaotic inflation into a single scheme and it considers minimally and non-minimally coupled scenarios, adopting three classes of potentials, in both Jordan and Einstein frames. We show that, to obtain a suitable amount of particles obtained
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Reduction of mechanical losses in ion-beam sputtered tantalum oxide thin films via partial crystallization Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-24 Giulio Favaro, Valeria Milotti, Diego Alonso Diaz Riega, Nicole Busdon, Marco Bazzan, Massimo Granata, David Hofman, Christophe Michel, Laurent Pinard, Livia Conti, Simone Capaccioli, Nikita S Shcheblanov, Anaël Lemaître, Valérie Martinez, Gianpietro Cagnoli, Francesco Piergiovanni, Federica Fabrizi, Maria G Pelizzo, Alain J Corso
This study explores the impact of crystalline fraction on the mechanical losses of amorphous tantalum oxide (tantala, Ta2O5) thin films intended for gravitational wave detectors. We use ion beam sputtering technique to prepare a series of samples, which are then subjected to controlled thermal annealing to achieve varying degrees of crystallized fraction. The microscopic structure of the annealed samples
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Fuzzy bounces Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-24 Massimo Giovannini
We observe that the energy and the enthalpy densities can be smeared by two fudge factors that are constrained by the contracted Bianchi identities. Depending on the analytic properties of the smearing functions the underlying cosmological solutions belong to two physically different classes, namely the bounces of the scale factor and the curvature bounces. While the curvature bounces are naturally
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Design of optical telescopes for laser field wavefront reconstruction in gravitational-wave detectors Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-24 A Allocca, E Genin, M Mantovani, A Chiummo
Pick-off beams in Interferometric Gravitational Wave Detectors are often used to derive information on the field circulating in the interferometer. In order to retrieve the wavefront of the field at some chosen location, an optical system has to be deployed so to image the desired field characteristics to an optical bench and ultimately to suitable sensors. In this paper, we detail the requirements
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Hybrid geometrodynamics: a Hamiltonian description of classical gravity coupled to quantum matter Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-22 J L Alonso, C Bouthelier-Madre, J Clemente-Gallardo, D Martínez-Crespo
We generalize the Hamiltonian picture of general relativity coupled to classical matter, known as geometrodynamics, to the case where such matter is described by a quantum field theory in curved spacetime, but gravity is still described by a classical metric tensor field over a spatial hypersurface and its associated momentum. Thus, in our approach there is no non-dynamic background structure, apart
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Twistor initial data characterisation of pp-waves Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-17 Edgar Gasperín and Francisco Pais
This note gives a concise derivation of a twistor-initial-data characterisation of pp-wave spacetimes in vacuum. The construction is based on a similar calculation for the Minkowski spacetime in Bäckdahl and Kroon [2011 Class. Quantum Grav.28 075010]. The key difference is that for the Minkowski spacetime a necessary condition is that . In this note it is shown that if then the development is a pp-wave
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Conformal diagrams for stationary and dynamical strong-field hyperboloidal slices Classical Quant. Grav. (IF 3.5) Pub Date : 2024-04-15 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 )