This work is dedicated to discussing the influence of diverse redshift functions on the dynamics of traversable Morris–Thorne wormhole supported by a magnetic fluid source and a Yukawa–Casimir shape function. The field equations are used to determine the dynamical quantities of the supporting matter and are analyzed for the stability of wormholes. The study considers three different redshift functions [Formula: see text] For the zero-tidal-force cases ([Formula: see text] and [Formula: see text]), the constant gravitational potential eliminates radial tidal acceleration. At [Formula: see text] and [Formula: see text], the energy density remains negative near the throat, violating both the null and the strong energy conditions, confirming that exotic matter is required to maintain throat openness. Conversely, setting [Formula: see text] elevates the constant redshift parameter above a critical threshold ([Formula: see text]), enhancing the local classical gravitational binding energy relative to the negative Casimir vacuum fluctuations. As a result, the total effective energy density becomes positive throughout the domain, validating both the weak and null energy conditions, and demonstrating that a traversable wormhole can be physically sustained by non-exotic matter combined with a localized classical magnetic fluid. Finally, for the variable redshift case [Formula: see text], non-zero gravitational tidal forces are introduced; while tidal forces remain finite at the throatensuring human traversability for sufficiently large throat radiithe non-constant potential acts constructively with quantum vacuum fluctuations to require exotic negative energy density near the throat. Thus, the analysis demonstrates that the choice of redshift function significantly governs the supporting matter distribution.
This work presents a model of highly massive neutron stars within the f(R, T) gravity framework by investigating the combined effects of anisotropy, electric charge, and matter-geometry coupling on their equilibrium and stability in Karmarkar spacetime. Employing a generalized Chaplygin gas equation of state, the modified Einstein field equations yield the corresponding Tolman-Oppenheimer-Volkoff equation. The resulting Mass-Radius relation predicts the existence of supermassive neutron stars, PSR J0614-3329 and PSR J0437-4715, with masses of 3.23M ⊙ and 3.18M ⊙ and radii of 8.33 km and 8.40 km, respectively, exceeding the general relativistic mass limit while remaining consistent with current astrophysical observations.
Quantum fluctuation theorems provide fundamental constraints on entropy production but rely on a trajectory-based description that becomes problematic in the presence of coherence and incompatible measurements. While deviations from standard fluctuation relations in quantum regimes are often attributed to coherence, the precise nonclassical mechanism underlying such effects remains under active discussion. In this work, we investigate contextual interference effects in nonequilibrium thermodynamics using a minimal analytically solvable two-qubit heat-exchange model with a phase-tunable partial-swap interaction. By employing a coherence-preserving Kirkwood–Dirac (KD) quasiprobability formulation of energy exchange, we identify a single correction term, [Formula: see text], that quantifies deviations from the conventional fluctuation-theorem symmetry. We show that this correction originates from interference between incompatible measurement contexts within the degenerate single-excitation subspace and vanishes both in the incoherent limit and at thermal equilibrium. The resulting expression is fully analytic, depends on experimentally tunable parameters, and explicitly connects entropy-current fluctuations to phase-sensitive coherence effects. Our results provide an operationally accessible signature of KD-interference contributions in quantum thermodynamics and demonstrate that coherence, when combined with measurement incompatibility, induces a well-defined correction to fluctuation relations. This establishes a minimal framework linking contextual interference and thermodynamic irreversibility and suggests experimentally feasible routes for probing such effects on current quantum platforms.
This study explored several options for organizing the longitudinal spin orientation of a polarized electron beam at its collision point with positrons in the currently accepted geometry of super-tau charm factory of the University of Science and Technology of China (USTC) in Hefei. Modifications to the collider’s optics were considered, using either one or three spin rotators of Siberian snake-type. A variant with two partial Siberian snakes with a half-strength longitudinal magnetic field was also studied. The best polarization lifetime, achieved by injecting a linearly accelerated beam of polarized electrons from a gun with a polarized photocathode with an initial polarization degree greater than 90% into the collider ring, is achieved with a variant with three Siberian snakes. In the range from 1 GeV to 2.5[Formula: see text]GeV, this time, taking into account the depolarizing effect of damping wigglers, smoothly decreases from 1600 s to 300 s. However, even with shorter polarization lifetimes, it is possible to maintain a high average polarization level, say above 80%, by frequently completely replacing spent bunches with fresh ones with a high initial degree of polarization. This approach is envisioned in the STCF project. Technically less complex and cheaper options with a single Siberian snake or two partial snakes provide acceptable polarization lifetimes in the energy range from 1 GeV to 1.7[Formula: see text]GeV. The paper also discusses the technical possibility of frequent particle spin flips, thereby creating equal background conditions when collecting statistics with a change in the sign of the spin projection onto the collision axis.
A full causal treatment of the dynamics of viscous dissipative gravitational collapse is developed in this study in the framework of Rastall gravity. We extend the Misner-Sharp formalism for gravitational collapse to account for dissipative effects in both the free-streaming and diffusive regimes. The former regime is valid when the characteristic size of the system is much smaller than the typical distance a particle travels before undergoing a collision (its mean free path), and the latter regime is appropriate in optically thick environments where spatial gradients serve as the primary driver of the fluxes. Subsequently, the Israel-Stewart framework couples the dynamical equation to relativistic relaxation equations for the energy flux, viscous shear, and dissipative bulk term, while maintaining the thermodynamic coupling coefficients between viscosity and heat. The obtained results are also contrasted with earlier studies in which those coefficients were omitted and viscous quantities were not described by causal transport equations. Our findings could find applications in specific astrophysical environments and physical conditions.
In this work, we construct a formulation of mixed systems, i.e. wormholes embedded within modified Tolman VII-like shells of neutron fluid. We derive the formalism for the temporal metric function, the mass-radius relation of the system, and the exact expression of the echo time. All considered configurations lead to mixed systems that can enter the ultracompact regime, allowing the echo time to be computed reliably. Our numerical results show that echo time have extremely short durations, of order 10 -1 ms and 10 -2 ms.
In this study, we consider a cosmological model based on Rényi holographic dark energy within the context of an anisotropic Bianchi type III space-time geometry. The dark energy density is taken as a modified function of the Hubble parameter, which enables us to express the Einstein field equations in a closed dynamical system. By solving these equations, we obtain the evolution of the Hubble parameter and examine the main cosmological implications of the model. The physical behavior of the universe is discussed through the analysis of the equation-of-state parameter as well as the deceleration parameter. Our results indicate that the universe evolves from an initial decelerated expansion phase toward a late-time accelerated regime. In the asymptotic limit, the model tends to a de Sitter phase, suggesting the presence of a stable attractor configuration. In addition, we reconstruct the dark energy component in terms of different scalar field frameworks, namely quintessence, tachyon, and k-essence models. The associated scalar fields and their potentials are derived and numerically investigated. The obtained results show a coherent late-time behavior, which is in agreement with the observed accelerated expansion of the universe. The small value of the mean anisotropy parameter indicates that this evolution occurs within a quasi-isotropic Bianchi type III background.
We study chiral symmetry breaking in the Nambu-Jona-Lasinio model on a de Sitter background, treating it as a non-renormalizable effective field theory with a physical ultraviolet cutoff. Using exponential proper-time regularization, we obtain an exact solution for the constituent fermion mass in the strong-curvature regime via the Lambert W function. The consistency condition for real-valued solutions leads to an upper bound on the cosmological constant, indicating a limitation of the mean-field description rather than a fundamental physical constraint on the spacetime geometry.
The astrophysical S-factor of the 7 Li(p,[Formula: see text]Be reaction has been studied at low energies with including an information about asymptotic normalization coefficient for the 7 Li+p[Formula: see text]Be configuration. In order to do this, the differential cross-section of the proton transfer reaction 7 Li( 3 He,d) 8 Be at energy of 24.3[Formula: see text]MeV has been analyzed within the framework of the modified distorted wave Born approximation (MDWBA). The value of ANC for the 7 Li+p[Formula: see text]Be(0[Formula: see text], E = 0.0[Formula: see text]MeV) configuration was derived to be 58.43[Formula: see text]1.95 fm[Formula: see text]. The values of ANCs for the 7 Li+p[Formula: see text]Be(2[Formula: see text], E = 3.04[Formula: see text]MeV) configuration were extracted to be 16.67[Formula: see text] [Formula: see text] [Formula: see text]0.54[Formula: see text]fm[Formula: see text] and 9.73[Formula: see text] [Formula: see text] [Formula: see text]0.31[Formula: see text]fm[Formula: see text] for total angular momentum [Formula: see text] and [Formula: see text], respectively. These ANC values were used in estimating the astrophysical [Formula: see text] factor of proton radiative capture by the 7 Li nucleus at astrophysically relevant energies within the framework of the modified R-matrix method. The value of the total astrophysical S factor of the 7 Li(p,[Formula: see text]Be reaction at zero energy was found to be [Formula: see text] = 1.35[Formula: see text]keV b. The reaction rate of the 7 Li(p,[Formula: see text]Be process was calculated over the relevant temperature range of astrophysical interest.
The main objective of this work is to determine the energy spectrum and the associated eigenfunctions of specific diatomic molecules. This study of light diatomic molecules with zero electronic spin is carried out in a relativistic framework, restricted to either weak relativistic corrections or the non-relativistic limit. To this end, we use the extended conformable fractional Nikiforov-Uvarov method together with the conformable biconfluent Heun equation method to solve the Klein-Gordon equation associated with the conformable inverse decimal power potential. The fractional parameter alpha represents the exponent of deformation of the spatial metric, transforming the usual distance r into an effective distance r alpha alpha. This parameter extends the family of exactly solvable potentials and generates unprecedented fine structures in the spectra of HCl, LiH, and other diatomic molecules. It thus allows the spectrum to be tuned to describe systems ranging from the Kratzer potential to more general forms. The impact of the parameter alpha on the quantum energy spectra is discussed in detail. Decreasing alpha reduces the molecular energy and produces a narrower potential well, making the system more stable than in the classical case. This stability is accompanied by a reduction in vibrational motion, potentially allowing other types of motion to become dominant. Finally, alpha does not lift degeneracy; it simply shifts all energy levels globally. The accurate reproduction of the experimental spectra of HCl and LiH validates the approach of using the Klein-Gordon equation with a four-term inverse-power potential to describe real molecular systems while preserving relativistic consistency. The systematic behavior as a function of the parameter alpha provides a useful tool for exploring molecular properties under different bonding regimes.
We discuss the recent observation of an excess of events at the threshold energy for t (t) over bar production at the LHC - interpreted as a quasi-bound state of toponium - as possible evidence for strong gravity at the attometer scale. By incorporating in the theoretical analysis, the Sommerfeld factor for a putative strong gravity term related to the gravitoweak conjecture - in which gravity at the attometer scale has the same strength as charged weak interactions - an agreement within less than one standard deviation is achieved with the measured cross-section at CMS and ATLAS experiments. The consequences of this gravitoweak conjecture are then extended to t (t) over bar scattering at higher energies, predicting suppression of the related cross-sections above root s similar or equal to 4 TeV, when the produced t (t) over bar should merge into a microscopic black hole with no available decay channels other than Hawking radiation.
In this paper, we develop a unified semiclassical framework to quantify quantum-geometric corrections to the Hawking temperature of the (2+1)-dimensional BTZ black hole arising from noncommutative geometry and the Generalized Uncertainty Principle (GUP). The GUP correction is implemented through a perturbative deformation of the Hamilton-Jacobi tunneling structure, whereas noncommutative effects are introduced through a Seiberg-Witten deformation of the BTZ geometry. By using the WKB approximation applied to the GUP-modified Dirac equation (and its scalar analogue), we obtain analytical expressions for the corrected radial action and derive a common spin-independent first-order shift for the two field sectors considered. Noncommutative contributions appear at order Theta 2 through the Seiberg-Witten map, while GUP corrections depend on a geometric combination of the particle mass and angular momentum. Within the perturbative regime, the GUP correction suppresses the BTZ temperature, while the noncommutative correction produces a controlled temperature shift whose sign is governed by the coefficient & Cscr;NC. The results provide a mathematically coherent bridge between minimal length deformations, noncommutative geometry, and lower dimensional black hole thermodynamics.
In this work, we investigate a spatially homogeneous and anisotropic BT-[Formula: see text] cosmological model filled with a perfect fluid source in the framework of modified [Formula: see text] gravity. Exact solutions of the nonlinear field equations are obtained by assuming a power-law relation between [Formula: see text] and the average scale factor together with a proportionality condition between the shear and expansion scalars. The obtained model describes a continuously expanding Universe with positive energy density, negative pressure, and a negative deceleration parameter, supporting late-time accelerated expansion. The EoS parameter remains entirely in the phantom region [Formula: see text], while the [Formula: see text] phase-plane analysis exhibits attractor-like behavior. Energy condition analysis shows that the DEC is satisfied, whereas the NEC and SEC are violated, consequently, NEC violation is a sign of exotic phantom behavior arising from modified [Formula: see text] gravity effects, while accelerated expansion results from SEC violation. Perturbative analysis indicates unstable behavior under small fluctuations. Furthermore, observational diagnostics including Hubble evolution, distance modulus show consistency with DA, BAO, [Formula: see text]CDM, and Pantheon datasets. Therefore, the obtained BT-[Formula: see text] framework provides an observationally viable description of late-time accelerated expansion in anisotropic modified gravity cosmology.
Using CUDA numerical methods exploited in machine learning computations, we investigate the ModMax AdS black holes in the presence of dark matter. After examining the singular and horizon behaviors, we study the effect of this dark sector on physical properties, including thermodynamics and shadows. By computing the associated quantities, we first reveal that such AdS black holes exhibit certain similarities to Van der Waals fluid systems. After that, we examine the effect of the dark matter on the associated optical quantities. Due to the complexity of the optical equations, we employ CUDA techniques to approach how external dark matter distributions influence optical properties such as shadows and energy emission rates. This provides a better understanding of how the charge and the dark matter external parameters alter optical observables, offering insights into astrophysical possibilities.
Resolving mass ordering is an important issue in the neutrino physics. In [Y. Hyodo and T. Kitabayashi, Mod. Phys. Lett. A 40, 2550097 (2025)] the authors investigate the phenomenology of a unified neutrino mixing framework and reveal that the predicted sum of neutrino masses derived from an approximate [Formula: see text] reflection symmetric flavor neutrino mass matrix based on the unified neutrino mixing with an inverted mass ordering, is excluded from DESI2024 and Supernova Ia luminosity distance data. We note that in [Y. Hyodo and T. Kitabayashi, Mod. Phys. Lett. A 40, 2550097 (2025)] an error is present in Eq. (20), i.e., the expression for [Formula: see text], a similar error also appears in Eq. (26) for [Formula: see text]. That is, the condition that [Formula: see text] and [Formula: see text] are real is omitted. We impose this condition and analyze its consequences. Using the newest data [O. Azzolini et al., Phys. Rev. Lett. 129, 111801 (2022); H. Acharya et al., Phys. Rev. Lett. 136, 022701 (2026)], it is obtained that the predicted sm derived from the approximate [Formula: see text] reflection symmetric neutrino mass matrices [Formula: see text] for both NO and IO are allowed. We note also that their conclusion is invalid, as it is based on outdated data.
In this work, we examine the kaon which comprises a light quark (q=u/d) and a strange antiquark ((s) over bar). The interaction between the constituent quark and antiquark is described using an effective equal admixture of scalar and vector linear potential V-q(r)=1/2(1+gamma(0))(a(2)r + V-0). This form of potential is thought to represent non-perturbative interactions between gluons. We compute hyperfine mass splitting for K-meson systems. Our computations consider the perturbative contributions of quark-gluon coupling, notably the effects of one-gluon exchange, center-of-mass, LS coupling and tensor corrections. The measured mass splitting produced in this investigation is reasonably consistent with the relevant experimental values. The estimated states 1(1)S(0)(494.71MeV) and 2(1)S(0)(1483.23MeV) for the K-meson agree satisfactorily with the Particle Data Group's estimates (495 MeV and 1482 MeV, respectively). The calculated masses of the 1(3)P(0),1(3)P(2),1(3)D(1),1(3)D(2),1(3)D(3), and 1(1)D(2) states reproduce the observed values with percentage deviations generally below 3%. The remaining radial and orbital excited states show adequate concordance with other theoretical models. Considering the equivalent parameters, we compute the various radiative decay widths of K*(nS) -> K(nS),n=1,2. Most of our outcomes are consistent with experimental and theoretical predictions.
We have investigated the deformation and orientation effects arising because of the deformed shape of the target on fusion excitation functions for various fusion mechanisms induced by 6 Li projectile on [Formula: see text]Tb target at around barrier energies using a semi-classical approach. The results indicate that target deformation and orientation alter the barrier characteristics and enhance the fusion cross-sections, especially at sub-barrier energies. The inclusion of deformation and orientation effects significantly improves agreement between predictions and data.
