cicyt UNIZAR

General Relativity and Quantum Cosmology

New submissions

[ total of 38 entries: 1-38 ]
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New submissions for Tue, 20 Mar 18

[1]  arXiv:1803.06346 [pdf, ps, other]
Title: Improving performance of SEOBNRv3 by $\sim$300x
Comments: 15 pages, 1 figure, 9 tables
Subjects: General Relativity and Quantum Cosmology (gr-qc)

When a gravitational wave is detected by Advanced LIGO/Virgo, sophisticated parameter estimation (PE) pipelines spring into action. These pipelines leverage approximants to generate large numbers of theoretical gravitational waveform predictions to characterize the detected signal. One of the most accurate and physically comprehensive classes of approximants in wide use is the "Spinning Effective One Body--Numerical Relativity" (SEOBNR) family. Waveform generation with these approximants can be computationally expensive, which has limited their usefulness in multiple data analysis contexts. In prior work we improved the performance of the aligned-spin approximant SEOBNR version 2 (v2) by nearly 300x. In this work we focus on optimizing the full eight-dimensional, precessing approximant SEOBNR version 3 (v3). While several v2 optimizations were implemented during its development, v3 is far too slow for use in state-of-the-art source characterization efforts for long-inspiral detections. Completion of a PE run after such a detection could take centuries to complete using v3. Here we develop and implement a host of optimizations for v3, calling the optimized approximant v3_Opt. Our optimized approximant is about 340x faster than v3, and generates waveforms that are numerically indistinguishable.

[2]  arXiv:1803.06368 [pdf, ps, other]
Title: Doppelgänger dark energy: modified gravity with non-conformal couplings after GW170817
Comments: 20 pages, no figures
Subjects: General Relativity and Quantum Cosmology (gr-qc)

Gravitational Wave (GW) astronomy severely narrowed down the theoretical space for scalar-tensor theories. We propose a (non-conformal) class of attractor models in which GWs propagate at the speed of light in the nearby universe but not in the past. To do so we derive new solutions to the interacting dark sector in which the ratio of dark energy and dark matter remains constant, which we refer to as {\it doppelg{\"a}nger dark energy} (DDE). We then remove the interaction between dark matter and dark energy by a suitable change of variables. The accelerated expansion that (we) baryons observe is due to a conformal coupling to the dark energy scalar field. We show how in this context it is possible to find a non trivial subset of solutions in which GWs propagate at the speed of light only at low red-shifts. The model is an attractor, thus reaching the limit $c_{T}\to1$ relatively fast. However, the effect of baryons turns out to be non-negligible and severely constrains the form of the Lagrangian. In passing, we found that in the simplest DDE models the no-ghost conditions for perturbations require a non-universal coupling to gravity. In the end, we comment on possible ways to solve the lack of matter domination stage for DDE models.

[3]  arXiv:1803.06400 [pdf, ps, other]
Title: The Unruh effect for mixing neutrinos
Comments: 7 pages
Subjects: General Relativity and Quantum Cosmology (gr-qc)

Recently, the inverse $\beta$-decay rate calculated with respect to uniformly accelerated observers (experiencing the Unruh thermal bath) was revisited. Concerns have been raised regarding the compatibility of inertial and accelerated observers' results when neutrino mixing is taken into account. Here, we show that these concerns are unfounded by discussing the properties of the Unruh thermal bath with mixing neutrinos and explicitly calculating the decay rates according to both sets of observers and confirming that they are in agreement. The Unruh effect is perfectly valid for mixing neutrinos.

[4]  arXiv:1803.06431 [pdf]
Title: Is Quintessence an Indication of a Time-Varying Gravitational Constant?
Subjects: General Relativity and Quantum Cosmology (gr-qc)

A model is presented where the quintessence parameter, w, is related to a time-varying gravitational constant. Assuming a present value of w equals -.98, we predict a current variation of G dot/G = -.06 H0. H0 is Hubbles parameter, G is Newtons constant and G dot is the derivative of G with respect to time. Thus, G has a cosmic origin, is decreasing with respect to cosmological time, and is proportional to H0, as originally proposed by the Dirac-Jordan hypothesis. Within our model, we can explain the cosmological constant fine-tuning problem, the discrepancy between the present very weak value of the cosmological constant, and the much greater vacuum energy found in earlier epochs. To formalize and solidify our model, we give two distinct functions of G(a), the cosmic scale parameter. We treat inverse G as an order parameter, which vanishes at high energies; at low temperatures, it reaches a saturation value, a value we are close to today. Our first function for inverse G is motivated by a charging capacitor; the second treats inverse G by analogy to a magnetic response. Both functions, even though very distinct, give a remarkably similar tracking behavior for w(a). Interestingly, both functions indicate the onset of G formation at a temperature of approximately 7 *1021 degrees Kelvin, in contrast to the concordance model. At the temperature of formation, we find that G has increased to roughly 4*1020 times its present value. For most of cosmic evolution, however, our variable G model gives results similar to the predictions of the concordance model, except in the very early universe, as we shall demonstrate. Within our framework, the weakening of G to its current value G0 is speculated as the true cause for the observed unanticipated acceleration of the universe.

[5]  arXiv:1803.06486 [pdf, ps, other]
Title: Rotating accretion flows in $D$ dimensions: sonic points, critical points and photon spheres
Comments: 11 pages
Subjects: General Relativity and Quantum Cosmology (gr-qc)

We give the formulation and the general analysis of the rotational accretion problem on $D$-dimensional spherical spacetime and investigate sonic points and critical points. First, we construct the simple two-dimensional rotating accretion flow model in general $D$-dimensional static spherically symmetric spacetime and formulate the problem. The flow forms a two-dimensional disk lying on the equatorial plane and the disk is assumed to be geometrically thin and has uniform distribution in the polar angle directions. Analyzing the critical point of the problem, we give the conditions for the critical point and its classification explicitly and show the coincidence with the sonic point for generic equation of state (EOS). Next, adopting the EOS of ideal photon gas to the analysis, we reveal that there always exists a correspondence between the sonic points and the photon spheres of the spacetime. Our main result is that the sonic point of the rotating accretion flow of ideal photon gas must be on (one of) the unstable photon sphere(s) of the spacetime in arbitrary spacetime dimensions. This paper extends this correspondence for spherical flows shown in the authors' previous work to rotating accretion disks.

[6]  arXiv:1803.06527 [pdf, other]
Title: Presence of horizon makes particle motion chaotic
Comments: 5 pages + supplementary material, 6 figures
Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th); Chaotic Dynamics (nlin.CD)

We analyze the motion of a massless particle very near to the event horizon. It reveals that the radial motion has exponential growing nature which is the signature of the presence of chaos in the particle motion. This is being confirmed by investigating the Poincar$\acute{e}$ section of the trajectories with the introduction of a harmonic trap to confine the particle's motion. Two situations are investigated: (a) the black hole is {\it any} static, spherically metric and, (b) spacetime represents a stationary, axisymetric black hole (e.g., Kerr metric). In both cases, the largest Lyapunov exponent has upper bound which is the surface gravity of the horizon. We find that the inclusion of rotation in the spacetime introduces more chaotic fluctuations in the system. The possible implications are finally discussed.

[7]  arXiv:1803.06640 [pdf, ps, other]
Title: Quantum gravity corrections to white dwarf dynamics
Comments: 31 pages, 4 figures
Subjects: General Relativity and Quantum Cosmology (gr-qc)

We study the invariant Planck scale correction to the white dwarf dynamics. We have considered the modified dispersion relation and the cut-off to the maximum possible momentum/energy of the non-interacting Fermi gas particles as a signal of appearance of the effects of Quantum Gravity phenomena. With such a modification the expression for the degenerate pressure of white dwarf gets modified accordingly and so does the Chandrasekhar mass limit. The mass-radius M-R plot shows that the modified/ corrected radius of the white dwarf can be greater than, equal to and smaller than the usual special relativity (SR) value for particular masses. We found that the Chandrasekhar mass limit gets a positive correction i.e, the maximum possible mass for white dwarf increases in this formalism. The correction is purely perturbative in the SR limit which is quite unusual for a theory having an ultraviolet energy cut-off. Therefore this correction is solely because of the modified dispersion relation. The value of the obtained degenerate pressure for a given mass is found to be greater than, equal to and smaller than the usual special relativity (SR) value for particular masses as expected. It is shown by Mishra et al. that the Stefan-Boltzmann law gets a correction in such a theory with an ultraviolet cut-off. Using this result we have calculated the luminosity of the white dwarf by taking the model of partially degenerate gas and considering the modified radiative envelope equation. In such an analysis we observe that the pressure for a given mass and temperature value is less than that predicted by the usual SR theory. The luminosity also gets a negative correction. The correction to luminosity is nonperturbative as expected for such a theory.

[8]  arXiv:1803.06666 [pdf, other]
Title: Causality Aspects of Modified Kerr-Newman spacetimes
Comments: 17 pages, 18 figures
Subjects: General Relativity and Quantum Cosmology (gr-qc)

In this paper, we address the problem of causality violation in the solutions of Einstein equations and seek possible causality restoration mechanisms in modifed theories of gravity. We choose for the above problem, the causality violation due to the existence of closed time-like curves in the context of Kerr-Newman black hole. We first revisit and quantify the details of the causality violation in the Kerr-Newman spacetime. We then show that the issue is also existent in two of the modified solutions to the Kerr Newman spacetime: The Non-Commutativity inspired solution and the f(R)-Gravity modifed solution. We explore the possibility of mechanisms present within the model that prevent causality violation. We show that, in both the models, the model parameters can be chosen such that the causality violating region is eliminated. We argue that in the context of non commutativity inspired solution, the non commutativity parameter can be chosen such that the causality violating region is eliminated and the inner horizon is no longer the Cauchy horizon. We then discuss the geodesic connectivity of the causality violating region in both the scenarios and quantify the geodesics that have points in the causality violating regions. We also discuss the causal aspects of Kerr Newman deSitter/antideSitter spacetimes.

[9]  arXiv:1803.06747 [pdf, other]
Title: Quantum effects near the Cauchy horizon of a Reissner-Nordstrom black hole
Authors: Orr Sela
Comments: 21 pages, 1 figure
Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)

We consider a massless, minimally-coupled quantum scalar field on a Reissner-Nordstrom black hole background, and study the leading asymptotic behavior of the expectation value of the stress energy tensor operator $<\hat{T}_{\mu\nu}>_{ren}$ and of $<\hat{\Phi}^{2}>_{ren}$ near the inner horizon, in both the Unruh and Hartle-Hawking quantum states. We find that the coefficients of the expected leading-order divergences of these expectation values vanish, indicating that the modifications of the classical geometry due to quantum vacuum effects might be weaker than expected. In addition, we calculate the leading-order divergences of $<\hat{T}_{\mu\nu}>_{ren}$ and $<\hat{\Phi}^{2}>_{ren}$ in Boulware state near the outer (event) horizon, and obtain analytical expressions that correspond to previous numerical results.

[10]  arXiv:1803.06836 [pdf, other]
Title: The art of the state
Comments: Expanded version of a talk given at the IV Amazonian Symposium on Physics. To appear in Int J Mod Phys D
Subjects: General Relativity and Quantum Cosmology (gr-qc)

Quantum field theory on curved spacetimes lacks an obvious distinguished vacuum state. We review a recent no-go theorem that establishes the impossibility of finding a preferred state in each globally hyperbolic spacetime, subject to certain natural conditions. The result applies in particular to the free scalar field, but the proof is model-independent and therefore of wider applicability. In addition, we critically examine the recently proposed "SJ states", that are determined by the spacetime geometry alone, but which fail to be Hadamard in general. We describe a modified construction that can yield an infinite family of Hadamard states, and also explain recent results that motivate the Hadamard condition without direct reference to ultra-high energies or ultra-short distance structure.

[11]  arXiv:1803.06946 [pdf, other]
Title: Dark energy and its manifestations
Comments: 12 pages, 6 figures
Subjects: General Relativity and Quantum Cosmology (gr-qc)

In a five-dimensional formalism we study the evolutionary behavior as well as the ultimate fate of the universe, in the course of which the contribution of dark energy in these phases are investigated. At one stage we get a situation (a condition) where the dark energy contained may contribute in maintaining the ecological balance of the universe. In the model universes we obtain here the dark energy is found to be of $\wedge$CDM and quintessence types-which bear testimony to being real universes. In one of the cases where the equation of state between the fluid pressure and density is of the type of the Van der waals equation, it is found that our universe may end in dust. And, also, it is seen that the behavior of the deceleration parameter is almost compatible with the recent observation.

Cross-lists for Tue, 20 Mar 18

[12]  arXiv:1803.01672 (cross-list from hep-th) [pdf, ps, other]
Title: On the observer dependence of the Hilbert space near the horizon of black holes
Comments: 56 pages plus appendix and references, 5 figures
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)

One of the pronounced characteristics of gravity, distinct from other interactions, is that there are no local observables which are independent of the choice of the spacetime coordinates. This property acquires crucial importance in the quantum domain in that the structure of the Hilbert space pertinent to different observers can be drastically different. Such intriguing phenomena as the Hawking radiation and the Unruh effect are all rooted in this feature. As in these examples, the quantum effect due to such observer-dependence is most conspicuous in the presence of an event horizon and there are still many questions to be clarified in such a situation. In this paper, we attempt to perform a comprehensive study of the observer dependence of the quantum Hilbert space of a massless scalar field in the vicinity of the horizon of the Schwarzschild black holes in four dimensions, both in the eternal (two-sided) case and in the physical (one-sided) case created by collapsing matter. Specifically, we compare and relate the Hilbert spaces of the three types of observers, namely (i) the freely falling observer, (ii) the observer who stays at a fixed proper distance outside of the horizon and (iii) the natural observer inside of the horizon analytically continued from outside. The relations we obtain have a number of important implications, such as on the quantum equivalence principle and the related firewall phenomenon, on the number of degrees of freedom seen by each type of observer, and on the "thermal-type" spectrum of particles realized in a pure state.

[13]  arXiv:1803.02548 (cross-list from cond-mat.quant-gas) [pdf, ps, other]
Title: Dynamics of first-order quantum phase transitions in extended Bose-Hubbard model: From density wave to superfluid and vice-versa
Comments: 10 pages, 13 figures
Subjects: Quantum Gases (cond-mat.quant-gas); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)

In this paper, we study the nonequilibrium dynamics of the Bose-Hubbard model with the nearest-neighbor repulsion by using time-dependent Gutzwiller (GW) methods. In particular, we vary the hopping parameters in the Hamiltonian as a function of time, and investigate the dynamics of the system from the density wave (DW) to the superfluid (SF) crossing a first-order phase transition and vice-versa. From the DW to SF, we find scaling laws for the correlation length and vortex density with respect to the quench time. This is a reminiscence of the Kibble-Zurek scaling for continuous phase transitions and contradicts the common expectation. On the other hand from the SF to DW, the system evolution depends on the initial SF state. When the initial state is the ground-state obtained by the static GW methods, a coexisting state of the SF and DW domains forms after passing through the critical point. Coherence of the SF order parameter is lost as the system evolves. This is a phenomenon similar to the glass transition in classical systems. Starting from the SF with small local phase fluctuations, the system is getting a large-size DW-domain structure with thin domain walls.

[14]  arXiv:1803.06756 (cross-list from hep-th) [pdf, other]
Title: Chaos of Wilson Loop from String Motion near Black Hole Horizon
Comments: 12 pages, 7 figures
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)

To find the origin of chaos near black hole horizon in string-theoretic AdS/CFT correspondence, we perform a chaos analysis of a suspended string in AdS black hole backgrounds. It has a definite CFT interpretation: chaos of Wilson loops, or in other words, sensitive time-evolution of a quark antiquark force in thermal gauge theories. Our nonlinear numerical simulation of the suspended Nambu-Goto string shows chaos, which would be absent in pure AdS background. The calculated Lyapunov exponent $\lambda$ satisfies the universal bound $\lambda \leq 2\pi T_{\rm H}$ for the Hawking temperature $T_{\rm H}$. We also analyze a toy model of a rectangular string probing the horizon and show that it contains a universal saddle characterized by the surface gravity $2\pi T_{\rm H}$. Our work demonstrates that the black hole horizon is the origin of the chaos, and suggests a close interplay between chaos and quark deconfinement.

[15]  arXiv:1803.06764 (cross-list from hep-th) [pdf, other]
Title: Exact holographic RG flows and the $A_{1}\times A_{1}$ Toda chain
Comments: latex, 55 pages, 34 figures
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); Mathematical Physics (math-ph)

We construct analytic solutions of Einstein gravity coupled to a dilaton field with a potential given by a sum of two exponentials, by rewriting the equations of motion in terms of an integrable Toda chain. Such solutions can be interpreted as domain walls interpolating between different asymptotics, and as such they can have interesting applications in holography. In some cases we can find flows that start from an AdS fixed point. We also find analytic black brane solutions at finite temperature. We discuss the properties of the solutions and the interpretation in terms of RG flow.

[16]  arXiv:1803.06851 (cross-list from astro-ph.CO) [pdf, ps, other]
Title: Cosmological Tests With Strong Gravitational Lenses using Gaussian Processes
Comments: 8 pages, 12 figures, 6 tables. Accepted for publication in the European Physical Journal C
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); Astrophysics of Galaxies (astro-ph.GA); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)

Strong gravitational lenses provide source/lens distance ratios D_obs useful in cosmological tests. Previously, a catalog of 69 such systems was used in a one-on-one comparison between the standard model, LCDM, and the R_h=ct universe, which has thus far been favored by the application of model selection tools to many other kinds of data. But in that work, the use of model parametric fits to the observations could not easily distinguish between these two cosmologies, in part due to the limited measurement precision. Here, we instead use recently developed methods based on Gaussian Processes (GP), in which D_obs may be reconstructed directly from the data without assuming any parametric form. This approach not only smooths out the reconstructed function representing the data, but also reduces the size of the 1-sigma confidence regions, thereby providing greater power to discern between different models. With the current sample size, we show that analyzing strong lenses with a GP approach can definitely improve the model comparisons, producing probability differences in the range ~10-30%. These results are still marginal, however, given the relatively small sample. Nonetheless, we conclude that the probability of R_h=ct being the correct cosmology is somewhat higher than that of LCDM, with a degree of significance that grows with the number of sources in the subsamples we consider. Future surveys will significantly grow the catalog of strong lenses and will therefore benefit considerably from the GP method we describe here. In addition, we point out that if the R_h=ct universe is eventually shown to be the correct cosmology, the lack of free parameters in the study of strong lenses should provide a remarkably powerful tool for uncovering the mass structure in lensing galaxies.

[17]  arXiv:1803.06910 (cross-list from astro-ph.CO) [pdf, other]
Title: Exploring neutrino mass and mass hierarchy in the scenario of vacuum energy interacting with cold dark matter
Comments: 11 pages, 4 figures
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Phenomenology (hep-ph)

We investigate the constraints on the total neutrino mass in the scenario of vacuum energy interacting with cold dark matter. We focus on two typical interaction forms, i.e., $Q=\beta H\rho_{\rm c}$ and $Q=\beta H\rho_{\Lambda}$. To avoid the occurrence of large-scale instability in interacting dark energy cosmology, we adopt the parameterized post-Friedmann approach to calculate the perturbation evolution of dark energy. We employ the observational data including the Planck cosmic microwave background temperature and polarization data, the baryon acoustic oscillation data, the JLA sample of type Ia supernovae observation, the direct measurement of the Hubble constant, and the redshift space distortions data. We find that, compared with those in the $\Lambda$CDM model, much looser constraints on $\sum m_{\nu}$ are obtained in the $Q=\beta H\rho_{\rm c}$ model, while slightly tighter constraints are obtained in the $Q=\beta H\rho_{\Lambda}$ model. After considering the mass hierarchies of neutrinos, the smallest upper limit results of $\sum m_{\nu}$ are given in the degenerate hierarchy case. By comparing the values of $\chi^2_{\rm min}$, we find that the normal hierarchy case is more favored than the inverted one. In particular, we find that the difference $\Delta \chi^2_{\rm min} \equiv \chi^2_{\rm IH; min}-\chi^2_{\rm NH; min}> 2$ in the $Q=\beta H\rho_{\rm c}$ model. In addition, we find that $\beta=0$ is consistent with the current observations in the $Q=\beta H\rho_{\rm c}$ model, and $\beta < 0$ is favored at the more than $1\sigma$ level in the $Q=\beta H\rho_{\Lambda}$ model.

[18]  arXiv:1803.06944 (cross-list from astro-ph.CO) [pdf, ps, other]
Title: Interacting Dark Energy: Possible Explanation for 21-cm Absorption at Cosmic Dawn
Comments: 4 pages, 2 figures
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)

A recent observation points to an excess in the expected 21-cm brightness temperature from cosmic dawn. In this paper, we present an alternative explanation of this phenomenon, an interaction in the dark sector. Interacting dark energy models have been extensively studied recently and there is a whole variety of such in the literature. Here we particularize to a specific model in order to make explicit the effect of an interaction.

[19]  arXiv:1803.06948 (cross-list from hep-th) [pdf, ps, other]
Title: Gravitational form factors and decoupling in 2D
Comments: 19 pages
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)

We calculate and analyse non-local gravitational form factors induced by quantum matter fields in curved two-dimensional space. The calculations are performed for scalars, spinors and massive vectors by means of the covariant heat kernel method up to the second order in the curvature and confirmed using Feynman diagrams. The analysis of the ultraviolet (UV) limit reveals a generalized "running" form of the Polyakov action for a nonminimal scalar field and the usual Polyakov action in the conformally invariant cases. In the infrared (IR) we establish the gravitational decoupling theorem, which can be seen directly from the form factors or from the physical beta function for fields of any spin.

Replacements for Tue, 20 Mar 18

[20]  arXiv:1507.08755 (replaced) [pdf, ps, other]
Title: The Cosmological Constant Problem and Quantum Spacetime Reference Frame
Authors: M.J.Luo
Comments: 15 pages; v4: updated to the published version in IJMPD, interpretation of NLSM being a theory of spacetime reference frame improved, running dimension in renormalization of NLSM and asymptotic safety formally demonstrated, limitations discussed, refs. added
Journal-ref: Int. J. Mod. Phys. D Vol.27(2018)1850081
Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th); Quantum Physics (quant-ph)
[21]  arXiv:1608.04014 (replaced) [pdf, ps, other]
Title: Cosmology of non-minimal derivative coupling to gravity in Palatini formalism and its chaotic inflation
Authors: Narakorn Kaewkhao (IF Naresuan), Burin Gumjudpai (IF Naresuan)
Comments: 12 pages, no figures, chaotic inflation potential section and appendices added, minor correction on Planck unit
Journal-ref: Physics of the Dark Universe 20 (2018) 20
Subjects: General Relativity and Quantum Cosmology (gr-qc)
[22]  arXiv:1701.02034 (replaced) [pdf, ps, other]
Title: Can black hole superradiance be induced by galactic plasmas?
Comments: 5 pages; v2. accepted version
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc)
[23]  arXiv:1702.03905 (replaced) [pdf, ps, other]
Title: Quantum principle of sensing gravitational waves: From the zero-point fluctuations to the cosmological stochastic background of spacetime
Comments: 14 pages, 4 figures, with typo corrections
Journal-ref: Phys. Rev. D 96, 044018 (2017)
Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Quantum Physics (quant-ph)
[24]  arXiv:1702.04916 (replaced) [pdf, ps, other]
Title: Constraints on a generalized deceleration parameter from cosmic chronometers
Authors: Abdulla Al Mamon
Comments: 9 pages, 5 figures, minor change in title, new references added, revised version accepted for publication in MPLA
Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
[25]  arXiv:1707.05351 (replaced) [pdf, ps, other]
Title: The reduced phase space of Palatini-Cartan-Holst theory
Comments: Corrected a minor mistake and reformulated some of the results. Main theorem restructured and overall improvements. 26 pages
Subjects: Mathematical Physics (math-ph); General Relativity and Quantum Cosmology (gr-qc); Symplectic Geometry (math.SG)
[26]  arXiv:1708.00204 (replaced) [pdf, ps, other]
Title: The extended Einstein-Maxwell-aether-axion model: Exact solutions for axionically controlled pp-wave aether modes
Comments: 8 pages, 0 figures. Replaced by the revised version published in Modern Physics Letters A; Introduction is extended, Remark, additional explanations and references are added
Journal-ref: Modern Physics Letters A, 33 (2018), 1850050
Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Theory (hep-th)
[27]  arXiv:1708.01253 (replaced) [pdf, other]
Title: Gravitational waves from first-order phase transitions: Towards model separation by bubble nucleation rate
Comments: 36 pages, 13 figures, 1 figure from arXiv:1605.01403
Journal-ref: JCAP 1711 (2017) no.11, 050
Subjects: High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
[28]  arXiv:1710.04965 (replaced) [pdf, ps, other]
Title: Lorentz signature and twisted spectral triples
Comments: minor corrections. To be published in JHEP
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); Mathematical Physics (math-ph)
[29]  arXiv:1710.05318 (replaced) [pdf, ps, other]
Title: On Finsler spacetimes with a timelike Killing vector field
Comments: 28 pages, AMSLaTex. v3: First part of the introduction and conclusions section expanded, some new references added; v3 matches the published version
Journal-ref: Class. Quantum Grav. 35 (2018) 085007 (28pp)
Subjects: Differential Geometry (math.DG); General Relativity and Quantum Cosmology (gr-qc)
[30]  arXiv:1710.06102 (replaced) [pdf, other]
Title: Exploring Short-GRB afterglow parameter space for observations in coincidence with gravitational waves
Comments: Published in MNRAS
Journal-ref: Monthly Notices of the Royal Astronomical Society, 474(4), 5340-5350 (2018)
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
[31]  arXiv:1710.06111 (replaced) [pdf, other]
Title: Rates of Short-GRB afterglows in association with Binary Neutron Star mergers
Comments: Published in MNRAS
Journal-ref: Monthly Notices of the Royal Astronomical Society 475(1), 699-707, (2018)
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
[32]  arXiv:1711.00283 (replaced) [pdf, ps, other]
Title: Center-of-Mass Equations of Motion and Conserved Integrals of Compact Binary Systems at the Fourth Post-Newtonian Order
Comments: 39 pages, published version
Journal-ref: Phys. Rev. D 97, 044037 (2018)
Subjects: General Relativity and Quantum Cosmology (gr-qc)
[33]  arXiv:1801.00966 (replaced) [pdf, ps, other]
Title: The black hole interior and the type II Weyl fermions
Authors: M.A.Zubkov
Comments: Latex, 14 pages
Journal-ref: Modern Physics Letters A Vol. 33, Nos. 7 & 8 (2018) 1850047
Subjects: General Relativity and Quantum Cosmology (gr-qc)
[34]  arXiv:1802.01193 (replaced) [pdf]
Title: Gravitational Wave Polarization Analysis of GW170814
Comments: Version 1 used incorrect strain signal ratios for GW170814 and should be discarded. Here we report on finding a larger range of source sky locations within the LIGO-VIRGO 90% credible region for which a vector polarization model is consistent with the observed strain signal ratios. Figures and references updated in v3
Subjects: General Relativity and Quantum Cosmology (gr-qc)
[35]  arXiv:1802.04264 (replaced) [pdf, other]
Title: White Holes as Remnants: A Surprising Scenario for the End of a Black Hole
Comments: 12 pages, 8 figures, references added
Subjects: General Relativity and Quantum Cosmology (gr-qc)
[36]  arXiv:1803.00332 (replaced) [pdf, other]
Title: Geometry Transition in Covariant Loop Quantum Gravity
Comments: PhD thesis submitted for the degree of Doctor in Theoretical and Mathematical Physics. Defended at the Center for Theoretical Physics/CNRS/Aix-Marseille University, the 23rd of October 2017. The manuscript is written in English and begins with a short summary in French
Subjects: General Relativity and Quantum Cosmology (gr-qc); Mathematical Physics (math-ph)
[37]  arXiv:1803.00738 (replaced) [pdf, ps, other]
Title: Notes on the gravitational, electromagnetic and axion memory effects
Comments: 18 pages
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)
[38]  arXiv:1803.04306 (replaced) [pdf, ps, other]
Title: Is there any consistent boundary condition for f (R) Gravity ?
Comments: 24 pages
Subjects: General Relativity and Quantum Cosmology (gr-qc)
[ total of 38 entries: 1-38 ]
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