By applying the island rule proposed recently, we compute the entanglement entropy of Hawking radiation and study the Page curve for the eternal black holes in massive gravity. We investigate for ...both the neutral and charged black holes which the corresponding results of Schwarzschild and Reissner–Nordström black holes are restored in the limit of massless graviton. We show for the neutral and non-extremal charged black holes that the island is not formed at the early times of the evaporation and hence the entanglement entropy increases linearly in time. However, for the extremal charged black hole, the calculation of the entanglement entropy at the early times without the island is ill-defined because the metric is divergent at the curvature singularity. This implies that new physics in the UV region must be taken into account to make the metric behaving smoothly at the very short distances. At the late times, with the emergence of one island near the event horizon, the entanglement entropy is saturated by the Bekenstein–Hawking entropy of black holes. In addition, we analyze the impact of massive gravity parameters on the size of island, the entanglement entropy, the Page time, and the scrambling time in detail.
In this paper, we represent a resolution for the hierarchy problem where the inverse size of the extra dimension and the fundamental Planck scale would all be of the order of the TeV scale by ...proposing a fiber fabric of spacetime. The origin of the large hierarchy is essentially due to the
cosh
function which is physically originated from the dynamics of the horizontal metric in the vacuum of non-zero energy. In addition, the fiber fabric of spacetime allows us to resolve elegantly and naturally the problems of the chirality fermions and stabilizing potential for the size of the extra dimension, which are usually encountered in the higher dimensional theories. Then, we explore the inflation with the modulus of the extra dimension identified as the inflaton where our slow-roll inflationary model belongs to the E-model class with
n
=
1
. We calculate the main inflationary observables which are consistent with the present experiments. Finally, we study how the geodesic motion of neutral test particles gets modified from the extension of spacetime. We compute the radius of the photon sphere, the innermost stable circular orbit, the perihelion shift, the light bending angle, and the observables of the strong gravitational lensing and the retrolensing phenomenon. By comparing the predicted values with the experimental observations, we determine the constraints on the fiber fabric of spacetime.
Background and purpose
Previous studies suggested that the overall burden of prior infections contributes to cardiovascular diseases and stroke. In the present study, the association between ...infectious burden (IB) and Alzheimer's disease (AD) was examined.
Methods
Antibody titers to common infectious pathogens including cytomegalovirus (CMV), herpes simplex virus type 1 (HSV‐1), Borrelia burgdorferi, Chlamydophila pneumoniae and Helicobacter pylori were measured by enzyme‐linked immunosorbent assay in 128 AD patients and 135 healthy controls. IB was defined as a composite serological measure of exposure to these common pathogens.
Results
Seropositivities toward zero−two, three and four−five of these pathogens were found in 44%, 40% and 16% of healthy controls but in 20%, 44% and 36% of AD patients, respectively. IB, bacterial burden and viral burden were independently associated with AD after adjusting for age, gender, education, APOE genotype and various comorbidities. Mini‐Mental State Examination scores were negatively correlated with IB in all cases. Serum beta‐amyloid protein (Aβ) levels (i.e. Aβ40, Aβ42 and total Aβ) and inflammatory cytokines (i.e. interferon‐γ, tumor necrosis factor α, interleukin‐1β and interleukin‐6) in individuals exposed to four−five infectious pathogens were significantly higher than those exposed to zero−two or three pathogens.
Conclusions
IB consisting of CMV, HSV‐1, B. burgdorferi, C. pneumoniae and H. pylori is associated with AD. This study supports the role of infection/inflammation in the etiopathogenesis of AD.
Click here to view the accompanying paper in this issue. Videocasts of this article are available in: English: http://player.polyv.net/videos/player.swf?vid=f6ee5715d9808c7a481b7ae727da00dd_f Mandarin: http://player.polyv.net/videos/f6ee5715d98ae743a9b0509d0900c91f_f.swf
An anomaly observed recently in the
8
Be
nuclear transition by the Atomki collaboration hints at a weakly-coupled, light new gauge boson with a mass of about 17 MeV. In this paper, we propose that ...this new gauge boson comes from a short-distance structure of the spacetime, rather than from an extension of the Standard Model through adding an extra
U
(
1
)
gauge symmetry. The dominant contribution to the relevant matrix element of the
8
Be
nuclear transition is given by the axial couplings. In order to account for the
8
Be
anomaly and satisfy the current experimental constraints, the coupling constant of the new gauge boson should be about
O
(
10
-
4
-
10
-
5
)
. Our theoretical model allows understanding the origin of the smallness of the coupling constant, which is still missing or being incompletely understood in the models at which the new gauge boson has the axial couplings.
The rotation curve (RC) of the Milky Way out to ~100 kpc has been constructed using ~16,000 primary red clump giants (PRCGs) in the outer disc selected from the LAMOST Spectroscopic Survey of the ...Galactic Anti-centre (LSS-GAC) and the Sloan Digital Sky Survey (SDSS)-III/APOGEE survey, combined with ~5700 halo K giants (HKGs) selected from the SDSS/SEGUE survey. To derive the RC, the PRCG sample of the warm disc population and the HKG sample of halo stellar population are, respectively, analysed using a kinematical model allowing for the asymmetric drift corrections and re-analysed using the spherical Jeans equation along with measurements of the anisotropic parameter beta currently available. The typical uncertainties of RC derived from the PRCG and HKG samples are, respectively, 5-7 km s super( -1) and several tens km s super( -1). We determine a circular velocity at the solar position, ... and an azimuthal peculiar speed of the Sun, ..., both in good agreement with the previous determinations. The newly constructed RC has a generally flat value of 240 km s super( -1) within a Galactocentric distance rof 25 kpc and then decreases steadily to 150 km s super( -1) at r ~ 100 kpc. On top of this overall trend, the RC exhibits two prominent localized dips, one at r ~ 11 kpc and another at r ~ 19 kpc. From the newly constructed RC, combined with other constraints, we have built a parametrized mass model for the Galaxy, yielding a virial mass of the Milky Way's dark matter halo of ... and a local dark matter density, ... (ProQuest: ... denotes formulae/symbols omitted.)
In this paper, we have considered the heat engine and Joule–Thomson expansion for the charged AdS black hole in the context of the nonlinear electrodynamics and massive gravity. For the black hole ...heat engine, we obtained the analytical expression for the efficiency in terms of either the entropies or the temperatures and pressures in various limits. For the Joule–Thomson expansion of the black hole, we derived the isenthalpic curves in
T
-
P
diagram, the Joule–Thomson coefficient, and the inversion curves. We also indicated in detail the effects of the nonlinear electrodynamics and massive gravity on the heat engine efficiency and the Joule–Thomson expansion of the black hole.
We have derived a non-linear charged black hole solution, in the AdS spacetime, which behaves asymptotically like the RN-AdS black hole but at the short distances like a dS geometry. Thus, the black ...hole is regular. The thermodynamic quantities of the black hole are derived. Also, we analyzed in details the phase transitions of the black hole by observing the discontinuity of the heat capacity at constant pressure and the cusp type double points in the Gibbs free energy-temperature graph. Furthermore, the thermodynamic phases and their stability are investigated relying on the off-sell Gibbs free energy. Finally, we calculated the critical exponents characterizing the behavior of the relevant thermodynamic quantities near the critical point.
In this paper, we have constructed a bottom-up holographic model for the color superconductivity (CSC) of the Yang-Mills theory with including the higher derivative corrections which allow us to ...study the CSC phase with the color number Nc ≥ 2 . First, we consider the CSC phase transition in the context of Einstein-Gauss-Bonnet (EGB) gravity. We analyze the Cooper pair condensate in the deconfinement and confinement phases which are dual to the planar GB-RN-AdS black hole and GB-AdS soliton, respectively, where the backreaction of the matter part is taken into account. By examining the breakdown of the Breitenlohner-Freedman bound in the background of the planar GB-RN-AdS black hole, we find that the positive GB coupling parameter α > 0 leads to a lower upper bound of the color number in comparison to Einstein gravity where the CSC phase for Nc ≥ 2 is not realized. But, with the α < 0 case it is possible to observe the Cooper pair condensate for Nc ≥ 2 with the reasonable magnitude of α . This is confirmed and the corresponding phase diagram is found by solving numerically the equations of motion for the gravitational system. In addition, we show that the CSC phase disappears in the confinement phase for the magnitude of α below a certain value which means that beyond that value it might lead to the breakdown region of the EGB gravity in investigating the CSC phase. However, the CSC phase transition occurring with Nc ≥ 2 requires the magnitude of the GB coupling parameter to be rather large. As a result, the GB term would no longer be considered as the correction and it also violates the boundary causality bound. We resolve this problem by including additionally the higher derivative correction for the Maxwell electrodynamics and the nonminimal coupled Maxwell field. Figure
From solving the equations of the motion for a system of Einstein gravity coupled to a non-linear electromagnetic field in the dS spacetime with two integral constants, we derived a static and ...spherical symmetric non-linear magnetic-charged black hole. It is indicated that this black hole solution behaves like a dS geometry in the short-distance regime. And, thus this black hole is regular. The structure of the black hole horizons is studied in detail. Also, we investigated the thermodynamics and the thermal phase transition of the black hole in both the local and global views. By observing the discontinuous change of the specific heat sign and the swallowtail structure of the free energy, we showed that the black hole can undergo a thermal phase transition between a thermodynamically unstable phase and a thermodynamically stable phase.
Blazars at the Cosmic Dawn Paliya, Vaidehi S.; Ajello, M.; Cao, H.-M. ...
The Astrophysical journal,
07/2020, Volume:
897, Issue:
2
Journal Article
Peer reviewed
Open access
The uncharted territory of the high-redshift (z 3) universe holds the key to understanding the evolution of quasars. In an attempt to identify the most extreme members of the quasar population, that ...is, blazars, we have carried out a multiwavelength study of a large sample of radio-loud quasars beyond z = 3. Our sample consists of nine γ-ray-detected blazars and 133 candidate blazars selected based on the flatness of their soft X-ray spectra (0.3-10 keV photon index ≤1.75), including 15 with Nuclear Spectroscopic Telescope Array (NuSTAR) observations. The application of the likelihood profile stacking technique reveals that the high-redshift blazars are faint γ-ray emitters with steep spectra. The high-redshift blazars host massive black holes ( ) and luminous accretion disks ( erg s−1). Their broadband spectral energy distributions are found to be dominated by high-energy radiation, indicating their jets are among the most luminous ones. Focusing on the sources exhibiting resolved X-ray jets (as observed with the Chandra satellite), we find the bulk Lorentz factor to be larger with respect to other z > 3 blazars, indicating faster moving jets. We conclude that the presented list of high-redshift blazars may act as a reservoir for follow-up observations, such as with NuSTAR, to understand the evolution of relativistic jets at the dawn of the universe.
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