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  • Electromagnetic coupling effects in natural inflation
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-29
    Hing-Tong Cho and Kin-Wang Ng

    In this work we study the effects of the electromagnetic coupling in natural inflation in a systematic manner using the Schwinger–Keldysh formalism. The corresponding influence functional is evaluated in the one-loop level. It can be interpreted as due to a single stochastic force. The equation of motion of the inflaton field is therefore given in the form of a Langevin equation. Lastly, the two-point

    更新日期:2020-07-30
  • Constraining gravity with eccentric gravitational waves: projected upper bounds and model selection
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-28
    Blake Moore and Nicolás Yunes

    Gravitational waves allow us to test general relativity in the highly dynamical regime. While current observations have been consistent with waves emitted by quasi-circular binaries, eccentric binaries may also produce detectable signals in the near future with ground- and space-based detectors. We here explore how tests of general relativity scale with the orbital eccentricity of the source during

    更新日期:2020-07-29
  • Initial data and first evolutions of dust clouds in bimetric relativity
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-28
    Mikica Kocic, Francesco Torsello, Marcus Högås and Edvard Mörtsell

    We present a method for solving the constraint equations in the Hassan–Rosen bimetric theory to determine the initial data for the gravitational collapse of spherically symmetric dust. The setup leads to equations similar to those for a polytropic fluid in general relativity, here called Lane–Emden-like equations. Using a numerical code which solves the evolution equations in the standard 3 + 1 form

    更新日期:2020-07-29
  • A cryogenic silicon interferometer for gravitational-wave detection
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-28
    R X Adhikari, K Arai, A F Brooks, C Wipf, O Aguiar, P Altin, B Barr, L Barsotti, R Bassiri, A Bell, G Billingsley, R Birney, D Blair, E Bonilla, J Briggs, D D Brown, R Byer, H Cao, M Constancio, S Cooper, T Corbitt, D Coyne, A Cumming, E Daw, R deRosa, G Eddolls, J Eichholz, M Evans, M Fejer, E C Ferreira, A Freise, V V Frolov, S Gras, A Green, H Grote, E Gustafson, E D Hall, G Hammond, J Harms, G

    The detection of gravitational waves from compact binary mergers by LIGO has opened the era of gravitational wave astronomy, revealing a previously hidden side of the cosmos. To maximize the reach of the existing LIGO observatory facilities, we have designed a new instrument able to detect gravitational waves at distances 5 times further away than possible with Advanced LIGO, or at greater than 100

    更新日期:2020-07-29
  • A method of enhancing the detection sensitivity of transient sources in time series with Gaussian stationary noise
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-28
    Richard Lieu and Kristen A Lackeos

    The Gaussian phase noise of intensity time series is demonstrated to be drastically reduced when the raw voltage data are digitally filtered through an arbitrarily large number n of orthornormal bandpass profiles (eigen-filters) sharing the same intensity bandwidth, and the resulting intensity series are co-added. Specifically, the relative noise variance of the summed series at the resolution of one

    更新日期:2020-07-29
  • Asymptotic symmetries and charges at spatial infinity in general relativity
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-28
    Kartik Prabhu and Ibrahim Shehzad

    We analyze the asymptotic symmetries and their associated charges at spatial infinity in four-dimensional asymptotically-flat spacetimes. We use the covariant formalism of Ashtekar and Hansen where the asymptotic fields and symmetries live on the three-manifold of spatial directions at spatial infinity, represented by a timelike unit-hyperboloid (or de Sitter space). Using the covariant phase space

    更新日期:2020-07-29
  • Cosmological viable models in f ( T , B ) theory as solutions to the H 0 tension
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-28
    Celia Escamilla-Rivera and Jackson Levi Said

    In this work we present a further investigation about teleparallel gravity cosmology. We demonstrate that according to the current astrophysical data (CC + Pantheon + BAO samplers with late Universe measurements SH0ES + H0LiCOW), an f ( T , B ) theory can provide another interpretation to the oscillatory behaviour of the dark energy equation of state when applied to late times. The four f ( T , B )

    更新日期:2020-07-29
  • The null-timelike boundary problems of linear wave equations in asymptotically anti-de Sitter spacetime
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-28
    Lin Zhang and Xiaoning Wu

    In this paper, we study the initial-boundary problem of the massive wave equation which is conformal regular on an asymptotically anti-de Sitter spacetime, where the initial-boundary data are given on an outgoing null hypersurface and a timelike hypersurface, and the asymptotic information is given on the future null infinity. After a conformal rescaling, this problem will reduce to a null-timelike

    更新日期:2020-07-29
  • Bose–Fermi cancellation of cosmological Coleman–Weinberg potentials
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-28
    S P Miao, L Tan and R P Woodard

    Cosmological Coleman–Weinberg potentials are induced when normal matter is coupled to the inflaton. It has long been known that the corrections from bosonic fields are positive whereas those from fermionic fields are negative. In flat space both take the form ± φ 4 ln( φ ), and they can be made to cancel by appropriately choosing the coupling constants. In an expanding Universe the bosonic and fermionic

    更新日期:2020-07-29
  • Supergravity on a three-torus: quantum linearization instabilities with a supergroup
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-28
    Atsushi Higuchi and Lasse Schmieding

    It is well known that linearized gravity in spacetimes with compact Cauchy surfaces and continuous symmetries suffers from linearization instabilities: solutions to classical linearized gravity in such a spacetime must satisfy so-called linearization stability conditions (or constraints) for them to extend to solutions in the full non-linear theory. Moncrief investigated implications of these conditions

    更新日期:2020-07-29
  • Solving the curvature and Hubble parameter inconsistencies through structure formation-induced curvature
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-28
    Asta Heinesen and Thomas Buchert

    Recently it has been noted by Di Valentino, Melchiorri and Silk (2019) that the enhanced lensing signal relative to that expected in the spatially flat ΛCDM model poses a possible crisis for the Friedmann–Lemaître–Robertson–Walker (FLRW) class of models usually used to interpret cosmological data. The ‘crisis’ amounts to inconsistencies between cosmological datasets arising when the FLRW curvature

    更新日期:2020-07-29
  • Generalised effective cosmology from group field theory
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-28
    Steffen Gielen and Axel Polaczek

    We extend various recent results regarding the derivation of effective cosmological Friedmann equations from the dynamics of group field theory (GFT). Restricting ourselves to a single GFT field mode (or fixed values of Peter–Weyl representation labels), we first consider dynamics given by a quadratic Hamiltonian, which takes the form of a squeezing operator, and then add a quartic interaction that

    更新日期:2020-07-29
  • Numerical investigations of the asymptotics of solutions to the evolutionary form of the constraints
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-16
    Károly Csukás and István Rácz

    Systematic numerical investigations of the asymptotics of near Schwarzschild vacuum initial data sets is carried out by inspecting solutions to the parabolic–hyperbolic and to the algebraic–hyperbolic forms of the constraints, respectively. One of our most important findings is that the concept of near Schwarzschild configurations, applied previously in [4, 5], is far too restrictive. It is demonstrated

    更新日期:2020-07-17
  • Numerical solutions to Einstein’s equations in a shearing-dust universe: a code comparison
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-15
    Julian Adamek, Cristian Barrera-Hinojosa, Marco Bruni, Baojiu Li, Hayley J Macpherson and James B Mertens

    A number of codes for general-relativistic simulations of cosmological structure formation have been developed in recent years. Here we demonstrate that a sample of these codes produce consistent results beyond the Newtonian regime. We simulate solutions to Einstein’s equations dominated by gravitomagnetism—a vector-type gravitational field that does not exist in Newtonian gravity and produces frame-dragging

    更新日期:2020-07-16
  • Quantum effects in gravity waves
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-12
    Thiago Guerreiro

    We discuss the quantum mechanical description of a gravitational wave interacting with a cavity electromagnetic field. Quantum fluctuations of the gravitational vacuum induce squeezing in the optical field. Moreover, this squeezing experiences revivals, a purely quantum effect. Measuring these gravitationally induced revivals, although out of reach from experiments, would provide evidence on the quantum

    更新日期:2020-07-13
  • Symmetry-breaking and zero-one laws
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-12
    Fay Dowker and Rafael D Sorkin

    We offer further evidence that discreteness of the sort inherent in a causal set cannot, in and of itself, serve to break Poincaré invariance. In particular we prove that a Poisson sprinkling of Minkowski spacetime cannot endow spacetime with a distinguished spatial or temporal orientation, or with a distinguished lattice of spacetime points, or with a distinguished lattice of timelike directions (corresponding

    更新日期:2020-07-13
  • Dynamics of a ##IMG## [http://ej.iop.org/images/0264-9381/37/15/155003/toc_cqgab9bbbieqn1.gif] {${\mathbb{Z}}_{2}$} symmetric EdGB gravity in spherical symmetry
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-09
    Justin L Ripley and Frans Pretorius

    We report on a numerical investigation of black hole evolution in an Einstein dilaton Gauss–Bonnet (EdGB) gravity theory where the Gauss–Bonnet coupling and scalar (dilaton) field potential are symmetric under a global change in sign of the scalar field (a ‘ ##IMG## [http://ej.iop.org/images/0264-9381/37/15/155003/cqgab9bbbieqn2.gif] {${\mathbb{Z}}_{2}$} ’ symmetry). We find that for sufficiently small

    更新日期:2020-07-10
  • Inside the final black hole: puncture and trapped surface dynamics
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-09
    Christopher Evans, Deborah Ferguson, Bhavesh Khamesra, Pablo Laguna and Deirdre Shoemaker

    A popular approach in numerical simulations of black hole binaries is to model black holes as punctures in the fabric of spacetime. The location and the properties of the black hole punctures are tracked with apparent horizons, namely outermost marginally outer trapped surfaces (MOTSs). As the holes approach each other, a common apparent horizon suddenly appears, engulfing the two black holes and signaling

    更新日期:2020-07-10
  • Matter-geometry entanglement in quantum cosmology
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-09
    Viqar Husain and Suprit Singh

    We present a study of the evolution of entanglement entropy of matter and geometry in quantum cosmology. For a variety of Gaussian initial states and their linear combinations, and with evolution defined with respect to a relational time, we show numerically that (i) entanglement entropy increases rapidly at very early times, and subsequently saturates to a constant non-zero value, and (ii) that the

    更新日期:2020-07-10
  • Hamilton–Jacobi hydrodynamics of pulsating relativistic stars
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-09
    John Ryan Westernacher-Schneider, Charalampos Markakis and Bing Jyun Tsao

    The dynamics of self-gravitating fluid bodies is described by the Euler–Einstein system of partial differential equations. The break-down of well-posedness on the fluid–vacuum interface remains a challenging open problem, which is manifested in simulations of oscillating or inspiraling binary neutron-stars. We formulate and implement a well-posed canonical hydrodynamic scheme, suitable for neutron-star

    更新日期:2020-07-10
  • Regular decoupling sector and exterior solutions in the context of MGD
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-09
    Ernesto Contreras, Francisco Tello-Ortiz and S K Maurya

    We implement the gravitational decoupling through the minimal geometric deformation method and explore its effect on exterior solutions by imposing a regularity condition in the Tolman–Oppenheimer–Volkoff equation of the decoupling sector. We obtain that the decoupling function can be expressed formally in terms of an integral involving the g tt component of the metric of the seed solution. As a particular

    更新日期:2020-07-10
  • Time-energy uncertainty relation for neutrino oscillations in curved spacetime
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-09
    Massimo Blasone, Gaetano Lambiase, Giuseppe Gaetano Luciano, Luciano Petruzziello and Luca Smaldone

    We derive the Mandelstam–Tamm time–energy uncertainty relation for neutrino oscillations in a generic stationary curved spacetime. In particular, by resorting to Stodolsky covariant formula of the quantum mechanical phase, we estimate gravity effects on the neutrino energy uncertainty. Deviations from the standard Minkowski result are explicitly evaluated in Schwarzschild, Lense–Thirring and Rindler

    更新日期:2020-07-10
  • Conformally flat slices of asymptotically flat spacetimes
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-08
    Miguel Duarte and David Hilditch

    For mathematical convenience initial data sets in numerical relativity are often taken to be conformally flat. Employing the dual-foliation formalism, we investigate the physical consequences of this assumption. Working within a large class of asymptotically flat spacetimes we show that the ADM linear momentum is governed by the leading Lorentz part of a boost even in the presence of supertranslation-like

    更新日期:2020-07-09
  • Gmunu : toward multigrid based Einstein field equations solver for general-relativistic hydrodynamics simulations
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-06
    Patrick Chi-Kit Cheong, Lap-Ming Lin and Tjonnie Guang Feng Li

    We present a new open-source axisymmetric general relativistic hydrodynamics code Gmunu ( g eneral-relativistic mu ltigrid nu merical solver) which uses a multigrid method to solve the elliptic metric equations in the conformally flat condition (CFC) approximation on a spherical grid. Most of the existing relativistic hydrodynamics codes are based on formulations which rely on a free-evolution approach

    更新日期:2020-07-07
  • Non-relativistic four dimensional p-brane supersymmetric theories and Lie algebra expansion
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-05
    Luca Romano

    We apply the Lie algebra expansion method to the ##IMG## [http://ej.iop.org/images/0264-9381/37/14/145016/cqgab8bbcieqn2.gif] {$\mathcal{N}=1$} super-Poincaré algerba in four dimensions. We define a set of p-brane projectors that induce a decomposition of the super-Poincaré algebra preparatory for the expansion. We show that starting from the ##IMG## [http://ej.iop.org/images/0264-9381/37/14/145016/cqgab8bbcieqn3

    更新日期:2020-07-06
  • Gravitation in terms of observables 2: the algebra of fundamental observables
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Rodolfo Gambini, Saeed Rastgoo and Jorge Pullin

    In a previous paper, we showed how to use the techniques of the group of loops to formulate the loop approach to gravity proposed by Mandelstam in the 1960’s. Those techniques allow to overcome some of the difficulties that had been encountered in the earlier treatment. In this approach, gravity is formulated entirely in terms of Dirac observables without constraints, opening attractive new possibilities

    更新日期:2020-07-02
  • Gravitational anomalies in nAdS 2 /nCFT 1
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Alejandra Castro and Beatrix Mühlmann

    We revisit the holographic description of the near horizon geometry of the BTZ black hole in AdS 3 gravity, with a gravitational Chern–Simons term included. After a dimensional reduction of the three dimensional theory, we use the framework of nAdS 2 /nCFT 1 to describe the near horizon physics. This setup allows us to contrast the role of the gravitational and conformal anomaly inherited from AdS

    更新日期:2020-07-02
  • Collins in Wonderland
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Ben David Normann and Sigbjørn Hervik

    What is the asymptotic future of a scalar-field model if the assumption of isotropy is relaxed in generic, homogeneous Universe models? This paper is a continuation of our previous work on Bianchi cosmologies with a p -form field (where p ∈ {1, 3})—or equivalently: an inhomogeneous, mass-less scalar gauge field with a homogeneous gradient. In this work we investigate such matter sector in general relativity

    更新日期:2020-07-02
  • Probing massive scalar fields from a pulsar in a stellar triple system
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Brian C Seymour and Kent Yagi

    Pulsar timing observations precisely test general relativity. Recently, the hierarchical triple system PSR J0337 + 1715 has placed new constraints on the existence of a fifth force from violation in the strong equivalence principle. Many alternative gravity theories exist with massive (pseudo-)scalar fields to explain a variety of phenomena from the accelerating expansion of the Universe at large scales

    更新日期:2020-07-02
  • More on dual actions for massive spin-2 particles
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    D Dalmazi and A L R dos Santos

    Here we start from a dual version of Vasiliev’s first order action for massless spin-2 particles (linearized first order Einstein–Hilbert) and derive, via Kaluza–Klein dimensional reduction from D + 1 to D dimensions, a set of dual massive spin-2 models. This set includes the massive ‘BR’ model, a spin-2 analogue of the spin-1 Cremmer–Scherk model. In our approach the linearized Riemann curvature emerges

    更新日期:2020-07-02
  • Generalized Vaidya solutions in bimetric gravity
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Marcus Högås, Mikica Kocic, Francesco Torsello and Edvard Mörtsell

    In general relativity, the endpoint of spherically symmetric gravitational collapse is a Schwarzschild–[(A)dS] black hole. In bimetric gravity, it has been speculated that a static end state must also be Schwarzschild–[(A)dS]. To this end, we present a set of exact solutions, including collapsing massless dust particles. For these, the speculation is confirmed.

    更新日期:2020-07-02
  • Hamilton–Jacobi approach for Regge–Teitelboim cosmology
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Alejandro Aguilar-Salas, Alberto Molgado and Efraín Rojas

    The Hamilton–Jacobi formalism for a geodetic brane-like Universe described by the Regge–Teitelboim model is developed. We focus on the description of the complete set of Hamiltonians that ensure the integrability of the model in addition to obtaining the Hamilton principal function S . In order to do this, we avoid the second-order in derivative nature of the model by appropriately defining a set of

    更新日期:2020-07-02
  • Rotating five-dimensional electrically charged Bardeen regular black holes
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-07-01
    Muhammed Amir, Md Sabir Ali and Sunil D Maharaj

    We derive a rotating counterpart of the five-dimensional electrically charged Bardeen regular black holes spacetime by employing the Giampieri algorithm on static one. The associated nonlinear electrodynamics source is computed in order to justify the rotating solution. We thoroughly discuss the energy conditions and the other properties of the rotating spacetime. The black hole thermodynamics of the

    更新日期:2020-07-02
  • Quantized scalar fields in curved spacetime background of thick brane
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-30
    Jian Wang and Yu-Xiao Liu

    In this paper, we adopt the method of quantum fields in curved spacetime to quantize a free scalar matter field in the braneworld background whose warped factor is of the form that could generate Pöschl–Teller potential. Then we consider the interaction between the scalar field ϕ ( x ) and a classical scalar source ρ ( x ) with the form ##IMG## [http://ej.iop.org/images/0264-9381/37/14/145009/cqgab971bieqn1

    更新日期:2020-07-01
  • Scattered light noise characterisation at the Virgo interferometer with tvf-EMD adaptive algorithm
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-30
    Alessandro Longo, Stefano Bianchi, Wolfango Plastino, Nicolas Arnaud, Antonino Chiummo, Irene Fiori, Bas Swinkels and Michal Was

    A methodology of adaptive time series analysis, based on empirical mode decomposition (EMD) and on its time varying version tvf-EMD, has been applied to strain data from the gravitational wave interferometer (IFO) Virgo in order to characterise scattered light noise affecting the sensitivity of the IFO in the detection frequency band. Data taken both during hardware injections, when a part of the IFO

    更新日期:2020-07-01
  • Perturbative deflection angles of timelike rays
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-24
    Yujie Duan, Weiyu Hu, Ke Huang and Junji Jia

    Geodesics of both lightrays and timelike particles with nonzero mass are deflected in a gravitational field. In this work we apply the perturbative method developed in reference [1] to compute the deflection angle of both null and timelike rays in the weak field limit for four spacetimes. We obtained the deflection angles for the Bardeen spacetime to the eleventh order of m / b where m is the ADM mass

    更新日期:2020-06-25
  • Opening the Pandora’s box at the core of black holes
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-24
    Raúl Carballo-Rubio, Francesco Di Filippo, Stefano Liberati and Matt Visser

    We present a geometric classification of all spherically symmetric spacetimes that could result from singularity regularization, using a kinematic construction that is both exhaustive and oblivious to the dynamics of the fields involved. Due to the minimal geometric assumptions underlying it, this classification encompasses virtually all modified gravity theories, and any theory of quantum gravity

    更新日期:2020-06-25
  • Utilizing aLIGO glitch classifications to validate gravitational-wave candidates
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-24
    Derek Davis, Laurel V White and Peter R Saulson

    Advanced LIGO data contains numerous noise transients, or ‘glitches’, that have been shown to reduce the sensitivity of matched filter searches for gravitational waves from compact binaries. These glitches increase the rate at which random coincidences occur, which reduces the significance of identified gravitational-wave events. The presence of these transients has precipitated extensive work to establish

    更新日期:2020-06-25
  • On perturbative constraints for vacuum f ( R ) gravity
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-24
    Daniel Molano, Fabián Darío Villalba, Leonardo Castañeda and Pedro Bargueño

    Perturbative techniques are important for modified theories of gravity since they allow to calculate deviations from general relativity without recurring to exact solutions, which can be difficult to find. When applied to models such as f ( R ) gravity, these techniques introduce corrections in the field equations that involve higher order derivatives. Such corrections must be handled carefully to

    更新日期:2020-06-25
  • Analytic solutions for parallel transport along generic bound geodesics in Kerr spacetime
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-24
    Maarten van de Meent

    We provide analytical closed form solutions for the parallel transport along a bound geodesic in Kerr spacetime. This can be considered the lowest order approximation for the motion of a spinning black hole in an extreme mass-ratio inspiral. As an illustration of the usefulness of our new found expressions we scope out the locations of spin–spin resonances in quasi-circular EMRIs. All solutions are

    更新日期:2020-06-25
  • Verlinde gravity effects on the orbits of the planets and the Moon in the Solar System
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-14
    Youngsub Yoon and Luciano Ariel Darriba

    In this work, we address the effects of a phenomenon known as Verlinde gravity. Here we show that its effect over the planets and the Moon in our Solar System is quite negligible. We find that the Verlinde gravity effects on the orbits of planets are at least 10 times smaller than the precision with which we can determine the Sun’s mass, and the one on the orbit of the Moon is about 100 times smaller

    更新日期:2020-06-14
  • On the oscillations and future asymptotics of locally rotationally symmetric Bianchi type III cosmologies with a massive scalar field
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-14
    David Fajman, Gernot Heißel and Maciej Maliborski

    We analyse spatially homogenous cosmological models of locally rotationally symmetric Bianchi type III with a massive scalar field as matter model. Our main result concerns the future asymptotics of these spacetimes and gives the dominant time behaviour of the metric and the scalar field for all solutions for late times. This metric is forever expanding in all directions, however, in one spatial direction

    更新日期:2020-06-14
  • Predicting the properties of black-hole merger remnants with deep neural networks
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-14
    L Haegel and S Husa

    We present the first estimation of the mass and spin magnitude of Kerr black holes resulting from the coalescence of binary black holes using a deep neural network. The network is trained on a dataset containing 80% of the full publicly available catalog of numerical simulations of gravitational waves emission by binary black hole systems, including full precession effects for spinning binaries. The

    更新日期:2020-06-14
  • Spritz: a new fully general-relativistic magnetohydrodynamic code
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-14
    F Cipolletta, J V Kalinani, B Giacomazzo and R Ciolfi

    The new era of multimessenger astrophysics requires the capability of studying different aspects of the evolution of compact objects. In particular, the merger of neutron star binaries is a strong source of gravitational waves and electromagnetic radiation, from radio to γ-rays, as demonstrated by the detection of GW170817 and its electromagnetic counterparts. In order to understand the physical mechanisms

    更新日期:2020-06-14
  • Cosmological quantum entanglement: a possible testbed for the existence of Kalb–Ramond field
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-14
    Tanmoy Paul and Narayan Banerjee

    In the present paper, we explore the possible effects of a second rank antisymmetric tensor field, known as Kalb–Ramond (KR) field, on cosmological particle production as well as on quantum entanglement for a massive scalar field propagating in a four dimensional FRW spacetime evolves through a symmetric bounce. For this purpose, the scalar field is considered to be coupled with the KR field and also

    更新日期:2020-06-14
  • Quantum corrections to a finite temperature BIon
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-14
    Behnam Pourhassan, Sanjib Dey, Sumeet Chougule and Mir Faizal

    In this paper, we will analyze a finite temperature BIon, which is a finite temperature brane–anti-brane wormhole configuration. We will analyze the quantum fluctuations to this BIon solution using the Euclidean quantum gravity. It will be observed that these quantum fluctuations produce logarithmic corrections to the entropy of this finite temperature BIon solution. These corrections to the entropy

    更新日期:2020-06-14
  • Joint search for isolated sources and an unresolved confusion background in pulsar timing array data
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-14
    Bence Bécsy and Neil J. Cornish

    Supermassive black hole binaries are the most promising source of gravitational-waves in the frequency band accessible to pulsar timing arrays. Most of these binaries will be too distant to detect individually, but together they will form an approximately stochastic background that can be detected by measuring the correlation pattern induced between pairs of pulsars. A small number of nearby and especially

    更新日期:2020-06-14
  • Black hole and cosmological particle production in Schwarzschild de Sitter
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-14
    Yue Qiu and Jennie Traschen

    We compute the spectra and total fluxes of quantum mechanically produced particles crossing the black hole and cosmological horizons in Schwarzchild de Sitter (SdS). Particle states are defined with respect to well-behaved, Kruskal coordinates near the horizons, and as a consequence we find that these spectra are generally non-thermal. The non-thermal Bogoliubov coefficient for a vacuum fluctuation

    更新日期:2020-06-14
  • Casimir plates under Robin boundary conditions: the case for curved spacetime
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-11
    Borzoo Nazari

    Influence of gravity on the quantum vacuum of a massless minimally coupled scalar field under Robin boundary conditions on parallel plates is investigated. We introduce the detailed calculation of the volume energy for the case the gravitational background is weak in its most general form for a static spacetime. It founds that the quantum vacuum usually reacts to the gravitational field by decreasing

    更新日期:2020-06-11
  • Toward fidelity and scalability in non-vacuum mergers
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-11
    Steven L Liebling, Carlos Palenzuela and Luis Lehner

    We study the evolution of two fiducial configurations for binary neutron stars using two different general relativistic hydrodynamics (GRHD), distributed adaptive mesh codes. One code, Had , has for many years been used to study mergers of compact object binaries, while a new code, MHDuet , has been recently developed with the experience gained with the older one as well as several novel features for

    更新日期:2020-06-11
  • Colliding waves in a model of nonlinear electrodynamics
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-11
    S Habib Mazharimousavi and M Halilsoy

    Bell–Szekeres (BS) solution for colliding electromagnetic waves in Einstein–Maxwell (EM) theory describes also colliding waves in nonlinear electrodynamics (NED) with an emergent cosmological constant. Our NED model covers the first leading orders to the well-known Heisenberg–Euler (HE) type in a particular gauge of pure magnetic field. Prior to the problem of collision we obtain dyonic solution for

    更新日期:2020-06-11
  • Isometries from gauge transformations
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-11
    Ernesto Frodden and Kirill Krasnov

    In four dimensions one can use the chiral part of the spin connection as the main object that encodes geometry. The metric is then recovered algebraically from the curvature of this connection. We address the question of how isometries can be identified in this ‘pure connection’ formalism. We show that isometries are recovered from gauge transformation parameters satisfying the requirement that the

    更新日期:2020-06-11
  • Massive unimodular gravity
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-10
    Enrique Alvarez, Jesus Anero, Guillermo Milans del Bosch and Raquel Santos-Garcia

    A ghost free massive deformation of unimodular gravity (UG), in the spirit of mimetic massive gravity , is shown to exist. This construction avoids the no-go theorem for a Fierz–Pauli type of mass term in UG by giving up on Lorentz invariance. In our framework, the mimetic degree of freedom vanishes on-shell.

    更新日期:2020-06-10
  • Investigating the complexity-equals-action conjecture in regular magnetic black holes
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-10
    Deyou Chen and Jie Jiang

    In this paper, we investigate the ‘complexity equals action’ conjecture in regular magnetic black holes for the Einstein gravity coupled to the nonlinear electrodynamics. Motivated by the result of the dyonic Reissner–Nordstrom-AdS black hole founded by Goto et al , we first evaluate the complexity for a static regular magnetic black hole and find that the growth rate also vanishes at the late times

    更新日期:2020-06-10
  • Quantum Einstein equations
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-10
    Detlef Dürr and Ward Struyve

    We derive the quantum Einstein equations (which are the quantum generalisation of the Einstein equations of classical gravity) from Bohmian quantum gravity. Bohmian quantum gravity is a non-classical geometrodynamics (in the ADM formalism) which describes the time evolution of a three-geometry and of a matter field (or other matter degrees of freedom) on a three manifold. The evolution is determined

    更新日期:2020-06-10
  • Gravitational-wave versus x-ray tests of strong-field gravity
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-06-10
    Alejandro Cárdenas-Avendaño, Sourabh Nampalliwar and Nicolás Yunes

    Electromagnetic observations of the radiation emitted by an accretion disk around a black hole, as well as gravitational wave observations of coalescing binaries, can be used to probe strong-field gravity. We here compare the constraints that these two types of observations can impose on theory-agnostic, parametric deviations from the Schwarzschild metric. On the gravitational wave side, we begin by

    更新日期:2020-06-10
  • Hidden symmetries for transparent de Sitter space
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-05-31
    Garrett Compton and Ian A Morrison

    It is known that odd-dimensional de Sitter space acts as a transparent potential for free fields. Previous studies have explained this phenomena by relating de Sitter free field equations of motion to the time-independent Schrödinger equation with known transparent potentials. In this work we show that de Sitter’s transparency is a consequence of an infinite set of ‘hidden’ symmetries. These symmetries

    更新日期:2020-05-31
  • Non-Euclidean Newtonian cosmology
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-05-28
    John D Barrow

    We formulate and solve the problem of Newtonian cosmology under the assumption that the absolute space of Newton is non-Euclidean. In particular, we focus on the negatively-curved hyperbolic space, H 3 . We point out the inequivalence between the curvature term that arises in the Friedmann equation in Newtonian cosmology in Euclidean space and the role of curvature in the H 3 space. We find the generalisation

    更新日期:2020-05-28
  • Contoured thermal deformation of mirror surface for detuning parametric instability in an optical cavity
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-05-28
    Bin Wu, Carl Blair, Li Ju and Chunnong Zhao

    Independent mode frequency control will improve the ability to suppress parametric instabilities in gravitational wave detectors. In this article we investigate a formalism that allows multiple cavity optical modes to be thermally tuned independently based on the transformation between the change in mode spacing and the mirror surface deformation. An FFT based cavity simulation software is used to

    更新日期:2020-05-28
  • Cosmological models with asymmetric quantum bounces
    Classical Quant. Grav. (IF 3.071) Pub Date : 2020-05-28
    P C M Delgado and N Pinto-Neto

    In quantum cosmology, one has to select a specific wave function solution of the quantum state equations under consideration in order to obtain concrete results. The simplest choices have been already explored, in different frameworks, yielding, in many cases, quantum bounces. As there is no consensually established boundary condition proposal in quantum cosmology, we investigate the consequences of

    更新日期:2020-05-28
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