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<jats:title>Abstract</jats:title> <jats:p>It has been shown that the Christodoulou version of the strong cosmic censorship (SCC) conjecture can be violated for a scalar field in a near-extremal Reissner-Nordstrom-de Sitter black hole. In this paper, we investigate the effects of higher derivative corrections to the Einstein-Hilbert action on the validity of SCC, by considering a neutral massless scalar perturbation in <jats:inline-formula> <jats:tex-math><?CDATA $ 5 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025103_M1.jpg" xlink:type="simple" /> </jats:inline-formula>- and <jats:inline-formula> <jats:tex-math><?CDATA $ 6 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025103_M2.jpg" xlink:type="simple" /> </jats:inline-formula>-dimensional Einstein-Maxwell-Gauss-Bonnet-de Sitter black holes. Our numerical results show that the higher derivative term plays a different role in the <jats:inline-formula> <jats:tex-math><?CDATA $ d = 5 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025103_M3.jpg" xlink:type="simple" /> </jats:inline-formula> case than it does in the <jats:inline-formula> <jats:tex-math><?CDATA $ d = 6 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025103_M4.jpg" xlink:type="simple" /> </jats:inline-formula> case. For <jats:inline-formula> <jats:tex-math><?CDATA $ d = 5 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025103_M5.jpg" xlink:type="simple" /> </jats:inline-formula>, the SCC violation region increases as the strength of the higher derivative term increases. For <jats:inline-formula> <jats:tex-math><?CDATA $ d = 6 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025103_M6.jpg" xlink:type="simple" /> </jats:inline-formula>, the SCC violation region first increases and then decreases as the higher derivative correction becomes stronger, and SCC can always be restored for a black hole with a fixed charge ratio when the higher derivative correction is strong enough. Finally, we find that the <jats:inline-formula> <jats:tex-math><?CDATA $ C^{2} $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025103_M7.jpg" xlink:type="simple" /> </jats:inline-formula> version of SCC is respected in the <jats:inline-formula> <jats:tex-math><?CDATA $ d = 6 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025103_M8.jpg" xlink:type="simple" /> </jats:inline-formula> case, but can be violated in some near-extremal regimes in the <jats:inline-formula> <jats:tex-math><?CDATA $ d = 5 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025103_M9.jpg" xlink:type="simple" /> </jats:inline-formula> case. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We studied the instability of regularized 4D charged Einstein-Gauss-Bonnet de-Sitter black holes under charged scalar perturbations. The unstable modes satisfy the superradiant condition, but not all of the modes satisfying the superradiant condition are unstable. The instability occurs when the cosmological constant is small and the black hole charge is not too large. The Gauss-Bonnet coupling constant further destabilizes black holes when both the black hole charge and the cosmological constant are small and further stabilizes black holes when the black hole charge is large.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We investigate the axion-like particle (ALP)-photon oscillation effect in the high-energy <jats:inline-formula> <jats:tex-math><?CDATA $\gamma$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025105_M1.jpg" xlink:type="simple" /> </jats:inline-formula>-ray spectra of PG 1553+113 and PKS 2155−304 measured by Fermi-LAT and H.E.S.S. The choice of extragalactic background light (EBL) model, which induces the attenuation effect in observed <jats:inline-formula> <jats:tex-math><?CDATA $\gamma$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025105_M2.jpg" xlink:type="simple" /> </jats:inline-formula>-ray spectra, affects the ALP implications. For the ordinary EBL model that prefers a null hypothesis, we set constraints on the ALP-photon coupling constant at 95% C.L. as <jats:inline-formula> <jats:tex-math><?CDATA $g_{a\gamma}\lesssim 5\times 10^{-11} ~{\rm{GeV}}^{-1}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025105_M3.jpg" xlink:type="simple" /> </jats:inline-formula> for the ALP mass <jats:inline-formula> <jats:tex-math><?CDATA $\sim 10$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025105_M4.jpg" xlink:type="simple" /> </jats:inline-formula> neV. We also consider the CIBER observation of the cosmic infrared radiation, which shows an excess at wavelengths of <jats:inline-formula> <jats:tex-math><?CDATA $\sim 1~\mu$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025105_M5.jpg" xlink:type="simple" /> </jats:inline-formula>m after the substraction of foregrounds. High-energy gamma-rays from extragalactic sources at high redshifts would suffer from a more significant attenuation effect caused by this excess. In this case, we find that the ALP-photon oscillation would improve the fit to the observed spectra of PKS 2155−304 and PG 1553+113 and find a favored parameter region at 95% C.L.. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We obtain an exact slowly rotating Einstein-bumblebee black hole solution by solving the corresponding <jats:inline-formula> <jats:tex-math><?CDATA $rr$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025106_M1.jpg" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math><?CDATA $t\phi$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025106_M2.jpg" xlink:type="simple" /> </jats:inline-formula> components of the gravitational field equations for both cases: A) <jats:inline-formula> <jats:tex-math><?CDATA $b_\mu=(0,b(r),0,0)$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025106_M3.jpg" xlink:type="simple" /> </jats:inline-formula> and B) <jats:inline-formula> <jats:tex-math><?CDATA $b_\mu= (0,b(r), \mathfrak{b}(\theta),0)$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025106_M4.jpg" xlink:type="simple" /> </jats:inline-formula>. Then, we check the other gravitational field equations and the bumblebee field motion equations using this solution. We find that for case A, there indeed exists a slowly rotating black hole solution for an arbitrary LV (Lorentz violation) coupling constant <jats:inline-formula> <jats:tex-math><?CDATA $\ell$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025106_M5.jpg" xlink:type="simple" /> </jats:inline-formula>; however, for case B, this slowly rotating solution exists if and only if coupling constant <jats:inline-formula> <jats:tex-math><?CDATA $\ell$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025106_M6.jpg" xlink:type="simple" /> </jats:inline-formula> is as small as or smaller than angular momentum <jats:italic>a</jats:italic>. Thus far, no full rotating black hole solution has been published; hence, the Newman-Janis algorithm cannot be used to generate a rotating solution in the Einstein-bumblebee theory. This is similar to the Einstein-aether theory, wherein only some slowly rotating black hole solutions exist. To study the effects of this broken Lorentz symmetry, we consider the black hole greybody factor and find that, for angular index <jats:inline-formula> <jats:tex-math><?CDATA $l=0$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025106_M7.jpg" xlink:type="simple" /> </jats:inline-formula>, LV constant <jats:inline-formula> <jats:tex-math><?CDATA $\ell$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025106_M8.jpg" xlink:type="simple" /> </jats:inline-formula> decreases the effective potential and enhances the absorption probability, which is similar to the results for the non-minimal derivative coupling theory. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We probe the universality of acceleration scale <jats:inline-formula> <jats:tex-math><?CDATA $ a_0$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025107_M1.jpg" xlink:type="simple" /> </jats:inline-formula> in Milgrom's modified Newtonian dynamics (MOND) using the recently released rotation curve data from SPARC galaxies. We divide the SPARC data into different subsamples according to the morphological types of galaxies, and fit the rotation curve data of each subsample with the theoretical prediction of MOND. MOND involves an arbitrary interpolation function which connects the Newtonian region and the MOND region. Here we consider five different interpolation functions that are widely discussed in the literature. It is shown that the best-fitting <jats:inline-formula> <jats:tex-math><?CDATA $ a_0$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025107_M2.jpg" xlink:type="simple" /> </jats:inline-formula> significantly depends on the interpolation functions. For a specific interpolation function, <jats:inline-formula> <jats:tex-math><?CDATA $ a_0$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025107_M3.jpg" xlink:type="simple" /> </jats:inline-formula> also depends on the morphological types of galaxies, implying that <jats:inline-formula> <jats:tex-math><?CDATA $ a_0$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025107_M4.jpg" xlink:type="simple" /> </jats:inline-formula> may be not a universal constant. Introducing a dipole correction to <jats:inline-formula> <jats:tex-math><?CDATA $ a_0$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025107_M5.jpg" xlink:type="simple" /> </jats:inline-formula> can significantly improve the fits. The dipole directions for four of the five interpolation functions point towards an approximately consistent direction, but <jats:inline-formula> <jats:tex-math><?CDATA $ a_0$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025107_M6.jpg" xlink:type="simple" /> </jats:inline-formula> still varies for different interpolation functions. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>A universal relation between the leading correction to the entropy and extremality was proposed in the work of Goon and Penco. In this paper, we extend this work to massive gravity and investigate thermodynamic extremality relations in a topologically higher-dimensional black hole. A rescaled cosmological constant is added to the action of the massive gravity as a perturbative correction. This correction modifies the extremality bound of the black hole and leads to shifts in the mass, entropy, etc. Regarding the cosmological constant as a variable related to pressure, we obtain the thermodynamic extremality relations between the mass and entropy, pressure, charge, and parameters <jats:italic>c<jats:sub>i</jats:sub> </jats:italic> by accurate calculations. Finally, these relations are verified by a triple product identity, which shows that the universal relation exists in black holes. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this paper, the Joule-Thomson expansion of Born-Infeld AdS black holes is studied in the extended phase space, where the cosmological constant is identified with the pressure. The Joule-Thomson coefficient, the inversion curves and the isenthalpic curves are discussed in detail using a 4-dimensional black hole. The critical point of a Born-Infeld black hole is depicted with varying parameter <jats:inline-formula> <jats:tex-math><?CDATA $ \beta $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025109_M1.jpg" xlink:type="simple" /> </jats:inline-formula> and the charge <jats:italic>Q</jats:italic>. In <jats:inline-formula> <jats:tex-math><?CDATA $ T-P $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025109_M2.jpg" xlink:type="simple" /> </jats:inline-formula> plane, the inversion temperature curves and isenthalpic curves are obtained with different parameter <jats:inline-formula> <jats:tex-math><?CDATA $ \beta $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025109_M3.jpg" xlink:type="simple" /> </jats:inline-formula> and charge <jats:italic>Q</jats:italic>. We find that the missing negative slope is still conserved in Born-Infeld black holes. We also extend our discussion to arbitrary dimension higher than 4. The critical temperature and the minimum of inversion temperature are compared. The ratio is asymptotically <jats:inline-formula> <jats:tex-math><?CDATA $ 1/2 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025109_M4.jpg" xlink:type="simple" /> </jats:inline-formula> as <jats:italic>Q</jats:italic> increases or <jats:inline-formula> <jats:tex-math><?CDATA $ \beta\to\infty $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025109_M5.jpg" xlink:type="simple" /> </jats:inline-formula> with <jats:inline-formula> <jats:tex-math><?CDATA $ D = 4 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025109_M6.jpg" xlink:type="simple" /> </jats:inline-formula>, and reproduces previous results at higher dimensions. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this study, we implemented the type II seesaw mechanism into the framework of the <jats:inline-formula> <jats:tex-math><?CDATA $U(1)_{\rm B-L}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025110_M1.jpg" xlink:type="simple" /> </jats:inline-formula> gauge model. To achieve this, we added a scalar triplet, <jats:inline-formula> <jats:tex-math><?CDATA $ \Delta $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025110_M2.jpg" xlink:type="simple" /> </jats:inline-formula>, to the canonical particle content of the <jats:inline-formula> <jats:tex-math><?CDATA $U(1)_{\rm B-L}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025110_M3.jpg" xlink:type="simple" /> </jats:inline-formula> gauge model. By imposing that the <jats:inline-formula> <jats:tex-math><?CDATA $U(1)_{\rm B-L}$?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025110_M4.jpg" xlink:type="simple" /> </jats:inline-formula> gauge symmetry be spontaneously broken at TeV scale, we show that the type II seesaw mechanism is realized at an intermediate energy scale, more precisely, at approximately <jats:inline-formula> <jats:tex-math><?CDATA $ 10^9 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025110_M5.jpg" xlink:type="simple" /> </jats:inline-formula> GeV. To prevent heavy right-handed neutrinos from disturbing the mechanism, we evoke a <jats:inline-formula> <jats:tex-math><?CDATA $ Z_2 $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025110_M6.jpg" xlink:type="simple" /> </jats:inline-formula> discrete symmetry. Interestingly, as a result, we have standard neutrinos with mass around eV scale and right-handed neutrinos with mass in TeV scale, with the lightest one fulfilling the condition of dark matter. We developed all of these in this study. In addition, we show that the neutral component of <jats:inline-formula> <jats:tex-math><?CDATA $ \Delta $?></jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpc_45_2_025110_M7.jpg" xlink:type="simple" /> </jats:inline-formula> may perform unproblematic non-minimal inflation with loss of unitarity. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>We study the linear instability of the charged massless scalar perturbation in regularized 4D charged Einstein-Gauss-Bonnet-AdS black holes by exploring their quasinormal modes. We find that the linear instability is triggered by superradiance. The charged massless scalar perturbation becomes more unstable with increasing Gauss-Bonnet coupling constant or black hole charge. Decreasing the AdS radius, on the other hand, will make the charged massless scalar perturbation more stable. The stable region in parameter space (<jats:italic>α</jats:italic>, <jats:italic>Q</jats:italic>, Λ) is given. Moreover, we find that the charged massless scalar perturbation is more unstable for larger scalar charge. The modes of multipoles are more stable than that of the monopole. </jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this study, we examine the laws of thermodynamics and the weak cosmic censorship conjecture in the normal and extended phase spaces of Born-Infeld-anti-de Sitter black holes by considering a charged particle absorption. In the normal phase space, the first and second laws of thermodynamics as well as the weak cosmic censorship are still valid. However, in the extended phase space, the second law of thermodynamics is violated for double-horizon black holes and part of single-horizon black holes. The first law of thermodynamics and the weak cosmic censorship conjecture are still valid for all types of black holes. In addition, we found that the shift of the metric function, which determines the locations of the horizons, takes the same form at the minimum point in both the normal and extended phase spaces, indicating that the weak cosmic censorship conjecture is independent of the thermodynamic phase space.</jats:p>