The European Physical Journal C最新文献

The effect of gravity is a key factor in understanding the physical phenomenon. Quantizing gravity is challenging task due to weak interactions of gravity in quantum world. The quantum nature of gravity can be witnessed by entanglement in an interferometric platform [Phys. Rev. D 105, 086024 (2022)]. A natural question arises concerning whether the quantization of gravity can be observed via other means. In this work, we propose an effective approach to witnessing the gravity-induced quantumness by quantum uncertainty relations, including entropy-based and coherence-based uncertainty relations. The theoretical frameworks for wave-particle, entropic uncertainty and coherence are established, which can prove the quantum nature of gravity. The three-measurement entropic uncertainty and coherence exhibit the oscillatory features for the gravity-induced phases in the interferometric scheme. It is found that the evolutionary dynamics of coherence is inversely correlated with the measured uncertainty. It can be interpreted that the reduction of systemic quantum resource leads to the increase of entropic uncertainty, and vice versa. When the entropic uncertainty reaches zero, systemic coherence is the maximum value, providing a viable physical explanation for the gravity-induced quantumness. It shows that the entropic uncertainty and coherence can be regarded as the reliable indicators for capturing the gravity-induced quantumness. Compared to entanglement-based gravity quantization scheme, it shows that the capabilities are equivalent for detecting the gravity-induced quantumness using entropy uncertainty, coherence, and entanglement. The results could lay a solid theoretical foundation for the potential applications of quantum gravity in quantum information science.

In this paper, we perform small perturbations around the circular timelike orbit in the equatorial plane of the Horndeski rotating black hole, and analyze the effects of Horndeski hair on the three fundamental frequencies of the epicyclic oscillations. Since this operation can model the quasiperiodic oscillations (QPOs) phenomena of the surrounding accretion disc, we then employ the MCMC simulation to fit the theoretical results with three QPO events, including GRO J1655-40, XTE J1859+226 and H1743-322, and constrain the characteristic radius r, black hole mass M and spinning parameter a, and the Horndeski hair parameter h. Our constraint on the Horndeski hair parameter is much tighter than QPOs simulation from the existed accretion models, suggesting slight deviation from classical Kerr black hole.

In this work, we construct new classes of topological black hole solutions in anti-de Sitter (AdS) spacetime using a novel model of nonlinear electrodynamics called Modification Maxwell (ModMax) and Modification phantom or Modification anti-Maxwell (ModAMax). We then evaluate the thermodynamic quantities and verify the first law of thermodynamics. Our study examines how the parameters of the ModMax and ModAMax fields, as well as the topological constant, affect the black hole solutions, thermodynamic quantities, and local and global thermal stabilities. Furthermore, within the framework of extended phase space thermodynamics, we analyze the Joule–Thomson expansion process and determine the inversion curves. This analysis reveals that the ModMax and ModAMax parameters significantly alter the cooling and heating behavior of these AdS black holes, depending on their topology. Finally, by treating these topological Mod(A)Max AdS black holes as heat engines, we assess their efficiencies, demonstrating that the parameters of nonlinear electrodynamics and horizon topology play crucial roles in enhancing or suppressing the system’s thermodynamic performance.

We develop and apply the Batalin–Fradkin–Vilkovisky (BFV) formalism for the covariant quantization of generic off-diagonal solutions of the Einstein equations in general relativity (GR). In the classical regime, such nonholonomic configurations are formulated entirely within GR and are characterized by nonlinear symmetries of generating functions, running cosmological constants, integration functions, and effective matter sources. These constructions are further extended to quantum gravity (QG) models involving effective local Lorentz symmetry violations and anisotropic scaling, as realized in Hořva–Lifshitz (HL)-type theories. The classical geometric framework is formulated on Lorentz manifolds endowed with nonholonomic 2+2 and 3+1 splitting structures and subsequently generalized to quantum configurations determined by HL-type generating functions. The 2+2 dyadic splitting, incorporating connection distortions, provides a systematic method for constructing exact and parametric classical and quantum solutions described by generating functions and effective sources depending on all spacetime coordinates, physical constants, and anisotropic scaling or deformation parameters. The complementary 3+1 splitting allows for a consistent implementation of the BFV quantization procedure. We demonstrate the renormalizability of off-diagonal quantum HL-type deformations of GR. The resulting classical and quantum nonholonomic BFV models represent viable candidates for asymptotically free theories of gravity and may provide a mechanism for resolving unitarity issues in QG. In appropriate classical limits, the framework reproduces physically relevant off-diagonal GR solutions with or without locally anisotropic scaling, offering potential applications to nonlinear classical and quantum phenomena in accelerating cosmology and dark energy and dark matter physics.

We present a systematic investigation of the thermodynamic topology for a broad class of asymptotically charged Anti-de Sitter (AdS) black holes in Einstein–Maxwell-Dilaton (EMD) theories, examining how scalar coupling parameters and spacetime dimensions influence black hole thermodynamics. Employing a topological approach that utilizes the torsion number of vector fields constructed from the generalized free energy, we characterize black hole states as topological defects within the thermodynamic parameter space. Through analytical solutions spanning dimensions (d = 4,) (d=5,) and (d=6,) including the Gubser–Rocha model, we demonstrate that variations in the dilaton coupling constant (delta ,) particularly near its critical value (delta _c,) induce transitions between distinct thermodynamic topological phases. Our analysis reveals that certain black hole solutions constitute a novel class designated as (W^{0-leftrightarrow 1+},) characterized by a torsion number (W = 1) that corresponds to a unique stability structure. We establish that Gubser–Rocha models belong to this topological classification. These results significantly expand the existing classification framework while reinforcing thermodynamic topology as a robust analytical tool for probing the universal properties of black holes in both gravitational and holographic contexts. The findings provide new insights into the relationship between microscopic couplings and macroscopic thermodynamic behavior in extended gravity theories.

In this article, we performed Simpson–Visser (SV)-regularization scheme to Anti-de Sitter (AdS) black holes and then studied thermal properties of the resulting spacetime geometry. We considered the validity of the first law of black hole thermodynamics in this case and derived an entropy formula consistent with this new regular geometry. Next, we carried out the free energy analysis and studied the phase structure of these black holes. We discovered non-trivial phase transition properties dependent on the SV-regularization parameter. We also considered the validity of the second law of black hole thermodynamics and analyzed a merger scenario of two equal mass SV-regular black holes. In particular, we investigated the impact of the SV-regularization parameter on the constraints on post-merger black hole mass. Interestingly, we found that the bounds initially increase and then fall sharply with increasing the SV-regularization parameter. All results are compared with standard black holes for vanishing SV-regularization parameter.

Maps of cosmic microwave background (CMB) are extracted from multi-frequency observations using a variety of cleaning procedures. However, in regions of strong microwave emission, particularly in the galactic plane from our own galaxy Milky Way and some extended or point sources, the recovered CMB signal is not reliable. Thus, a galactic mask is provided along with the cleaned CMB sky for use with that CMB map which excises sky regions that may still be potentially contaminated even after cleaning. So, to avoid bias in our inferences, we impose such a foreground mask. In this paper, we analyze a cleaned CMB map from Planck public release 3 to probe for any foreground residuals that may still be present outside the galactic mask where the derived CMB sky is considered clean. To that end, we employ a local cross-correlation coefficient statistic where we cross-correlate widely used foreground templates that trace galactic synchrotron, free-free, and thermal dust emission from our galaxy with the cleaned CMB sky. Using simulations, we find that few regions of the derived CMB sky are still contaminated and have to be omitted. Based on this study, we derived a mask that could be used in conjugation with the standard mask to further improve the purpose of galactic masks.

The dependence of (textrm{f}_{0})(980) production on the final-state charged-particle multiplicity is reported for proton–proton (pp) collisions at the centre-of-mass energy, (sqrt{s}=) 13 TeV. The production of (textrm{f}_{0})(980) is measured with the ALICE detector via the (textrm{f}_0 (980) rightarrow pi ^{+}pi ^{-}) decay channel in a midrapidity region of (|y|<) 0.5. The evolution of the integrated yields and mean transverse momentum of f(_{0})(980) as a function of charged-particle multiplicity measured in pp at (sqrt{s}=) 13 TeV follows the trends observed in pp at (sqrt{s}=) 5.02 TeV and in proton–lead (p–Pb) collisions at (sqrt{s_{textrm{NN}}}=) 5.02 TeV. Particle yield ratios of (textrm{f}_{0})(980) to (pi ^{pm }) and (textrm{K}^{*})(892)(^{0}) are found to decrease with increasing charged-particle multiplicity. These particle ratios are compared with calculations from the canonical statistical thermal model as a function of charged-particle multiplicity. The thermal model calculations provide a better description of the decreasing trend of particle ratios when no strange or antistrange quark composition for f(_{0})(980) is assumed, which suggests that the data do not support significant hidden strangeness in the (textrm{f}_{0} (980)).

We investigate the effects of Hawking radiation on quantum steering and steering asymmetry in a tripartite system embedded in Schwarzschild spacetime. All tripartite steering types were classified, comprising three (1rightarrow 2) and three (2rightarrow 1) steering cases. Through a systematic analysis of all physically relevant scenarios (including accessible and inaccessible modes), we classify three canonical scenarios with one, two and three physically accessible modes. In the scenario of three physically accessible modes, Hawking radiation disrupts quantum steering, with the maximum steering asymmetry during the two-way steering to one-way steering transition precisely demarcating the phase boundary between these regimes. For two physically accessible modes, Hawking radiation exhibits dual behavior: enhancing the steering from Alice and Bob to anti-Charlie under certain parameters while suppressing it under others, while net strengthening other steering types. When considering one physically accessible mode, the Hawking effect of the black hole significantly enhances quantum steering. These findings provide new insights into quantum correlations in curved spacetime and establish observable signatures of Hawking effects in quantum steering phenomena.

A finite formulation of quantum field theory based on a system of differential equations reminiscent of the Callan–Symanzik equations is discussed. This system of equations was previously formulated in the bare language, and we re-derive it in a fully renormalized language. For the latter, within a simple (phi ^4) toy model, it is shown that with a specific choice of renormalization conditions—namely, the on-shell scheme for the renormalized mass—this class of finite renormalization prescriptions is equivalent to the standard renormalization group equation written in the Callan–Symanzik–Ovsyannikov form.