Modern Physics Letters A最新文献

We investigate an isotropic and homogeneous flat dark energy model in $f(Q,C)$ gravity theory that is linear in non-metricity Q and quadratic in boundary term C as $f(Q,C)=Q+\alpha C^2$, where $\alpha$ is a model parameter. We have solved the field equations in flat Friedmann–Lemaitre–Robertson–Walker (FLRW) spacetime geometry and considered a relation in the form of Hubble function in total energy density parameters ${\mathrm{\Omega }}_{m0}$, ${\mathrm{\Omega }}_{0(Q,C)}$, and Hubble constant $H_0$. We have compared our results with two observational datasets $H(z)$ and Pantheon SNe Ia datasets by using MCMC analysis and have obtained the best fit present values of parameters. We have used these best fit values throughout in result analysis and discussion. We have found the equation of state (EoS) parameter as $-1\le \omega \le 0.2$ over $-1\le z\le 3$. We have also investigated the Om diagnostic function and present age of the universe for these two datasets.

We study generalized ghost dark energy model in Brans–Dicke theory within the framework of flat Friedmann–Lemaitre–Robertson–Walker Universe. We assume the well-motivated logarithmic form of Brans–Dicke scalar field in terms of the scale factor to find the observational parameters such as equation of state parameter $w_g$ and deceleration parameter q. It is observed that the equation of state parameter crosses the phantom divide line $(w_g=-1)$ for a suitable range of model parameters. We observe that the deceleration parameter is time-dependent which shows the recent phase transition from decelerated to accelerated expansion of the Universe. Moreover, the model shows that the Universe will go through two future phase transitions, recent accelerated expansion to decelerated expansion and again decelerated expansion to accelerated expansion. We have also plotted the trajectories of the model in the $w_g-w_g^{\prime }$ plane for different values of parameters and explored the freezing and thawing regions. Further, we apply the sound squared speed method to check the stability of the model and found that the model is stable for suitable range of parameters.

Searches for Lepton Flavor Violation (LFV) stand at the forefront of experimental particle physics research, offering a sensitive probe to many scenarios of physics beyond the Standard Model. The high proton–proton collision energy and luminosity provided by the CERN Large Hadron Collider (LHC) and the excellent CMS detector performance allow for an extensive program of LFV searches. This paper reviews a broad range of LFV searches conducted at the CMS experiment using data collected in LHC Run 2, including $\tau \to 3\mu$ decays, Higgs boson decays, and top quark production and decays. In each analysis, the online and offline event selections, signal modeling, background suppression and estimation, and statistical interpretation are elucidated. These searches involve various final state particles in a large transverse momentum range, showcasing the capability of the CMS experiment in exploring fundamental questions in particle physics.

Both statistical and thermodynamic aspects are used to analyze the collapse of N self-gravitating black holes that result in the formation of supermassive black holes. The change in energy and entropy of the system in relation to the masses of the constituent black holes and their numbers are obtained. The transition temperature for the change from the high-temperature interacting gas (or particles) to the low-temperature condensed state of black holes in forming supermassive black hole is determined.

The binary tetrahedral group ($T^{\prime }$) has provided the most successful flavor symmetry in understanding simultaneously the three mixing angles both for quarks in the CKM matrix and for neutrinos in the PMNS matrix. One prediction, invariant under leptonic CP violation, relates the atmospheric and reactor neutrino mixings ${\theta }_{32}$ and ${\theta }_{13}$, respectively. We study sedulously this relation using the latest neutrino data. It is natural to focus on the frustrating experimental octant ambiguity of ${\theta }_{32}$. We conclude that the flavor symmetry requires that ${\theta }_{32}$ is in the second octant ${\theta }_{32}>45^{\circ }$, not in the first one ${\theta }_{32}<45^{\circ }$, and eagerly await experimental confirmation of this prediction.

The observed absence of the small-t oscillations in differential cross-section of the elastic scattering is considered as a consequence of the reflective scattering mode appearance at the highest energy of the LHC $\sqrt{s}=13$$$TeV.

Einstein–Podolsky–Rosen (EPR) paradox highlights the absence of a local realistic explanation for quantum mechanics, and shows the incompatibility of the local-hidden-state models with quantum theory. For N-qubit states, or more importantly, the N-qubit mixed states, we present the EPR steering paradox in the form of the contradictory equality “$2=1$”. We show that the contradiction holds for any N-qubit state as long as both “the pure state requirement” and “the measurement requirement” are satisfied. This also indicates that the EPR steering paradox exists in more general cases. Finally, we give specific examples to demonstrate and analyze our arguments.

In this paper, a tripartite quantum teleportation scheme in de Sitter vacuum is constructed. Then we investigate the influence of vacuum fluctuation, temperature and two-atom distance on performance of the tripartite quantum teleportation. It is found that fidelity drops fast with temperature and evolution time increasing. While temperature is low relatively, the influence of two-atom distance cannot be negligible, the change of fidelity is different with two-atom separation and time varying. The results may be helpful for dealing with quantum information tasks in curve spacetime and exploring the properties of curve spacetime through quantum information means.

In this paper, we study the Van der Waals black holes (the case $b=0$) in the anti-de Sitter space under the effect of the linear extended uncertainty principle (EUP). The analysis was undertaken using deep learning by employing physics-informed neural networks in addition to the semi-classical approach, we have calculated the thermal quantities, including mass, volume, temperature, entropy, and Gibbs free energy. Additionally, we visually depict the effects of the EUP-term on the thermodynamic properties of the studied black holes.