Search

The possibility of the existence of multiquark hadrons made of 4-quarks for mesons and 5-quarks for baryons was predicted by Gell-Mann [Phys. Lett. 8, 214 (1964)]. The renewed interest for the search for exotic pentaquark states was initiated by the paper by Diakonov, Petrov, and Polyakov [Z. Phys. A 359, 305 (1997)]. The 2003 experimental reports on the observation of Θ + pentaquark with u u d d s ̄ quark content created a great excitement and many following experiments have reported its observation [K. H. Hicks, Eur. Phys. J. H 37, 1 (2012)]. After high-statistics experiments at JLab, which did not confirm previous claims by the CLAS collaboration, the community concluded that the Θ + pentaquark either does not exist at all or has an extremely small cross-section, making it currently unobserved. There were different review papers on this subject, questioning the existence of Θ + or trying to explain the reasons why reaching a conclusion based on production experiments is challenging [M. Amaryan, Eur. Phys. J. Plus 137, 684 (2022)]. To address the challenge of minimal 3-body final states, a formation experiment with a projectile-kaon beam is proposed. In the following, we discuss how the Θ + could be observed in the K L p → Θ + → K + n reaction in the KLF experiment at JLab [M. Amaryan et al. [KLF Collaboration], arXiv:2008.08215 [nucl-ex]]. [ABSTRACT FROM AUTHOR]

The dynamical map represents a fundamental concept in quantum field theory, providing a solution of the field equations in the Fock space of asymptotic fields. In this paper, we show how to express the dynamical map of a scalar field in the language of quantum effective action. This grants us new insights into the study of topological defects in quantum field theory by showing a connection between the usual least-action principle and Umezawa’s boson transformation method. [ABSTRACT FROM AUTHOR]

In this paper, we study the evolution of Bianchi-I spacetimes within the framework of the Horndeski theory with G5=const./X. The spacetimes are filled a global unidirectional electromagnetic field interacting with a scalar field. We consider the minimal interaction and the non-minimal interaction by the law f2(ϕ)FμνFμν. The Horndeski theory allows anisotropy to grow over time, so the question arises of regulating the anisotropic level in this theory. Using the designer method, we build models in which the anisotropic level tends to a small value as the Universe expands. One of the results is a model with a anisotropic bounce. [ABSTRACT FROM AUTHOR]

This paper delves into the exploration of quantum resources within a two-qubit system composed of two 2-level atoms connected to distinct thermal baths. Various quantifiers are employed to evaluate different aspects of the system’s quantum characteristics. Specifically, the ℓ1-norm and relative entropy of coherence (풞ℓ1 and 풞r) are utilized to gauge quantum coherence, while local quantum Fisher information (LQFI) is used to quantify non-classical correlations within the system. The findings suggest that the amount of quantum correlations and coherence decline as the spontaneous emission rate γt and the mean thermal photon number n increase. However, it is observed that manipulating parameters defining the initial state of the two-level atoms system can enhance non-classical correlations and quantum coherence between the two atoms. Additionally, it is noted that these three key metrics entirely vanish in the asymptotic limit of time. Our research underscores the importance of precisely adjusting the parameters of the initial system state, which is prepared in an extended Werner-like state (EWL), to protect quantum resources shared between the two atoms from environmental influences. [ABSTRACT FROM AUTHOR]

Recently, the precise observations have yielded values for the neutrino mixing angles, denoted as θ12 and θ13. Therefore, constructing a neutrino mixing model capable of accurately reflecting these measurements is crucial. In this paper, we propose a novel neutrino mixing model similar to the trimaximal mixing model. Unlike the trimaximal model that falls short of concurrently replicating the best-fit values of θ12 and θ13, our proposed mixing model has the ability to simultaneously reproduce the best-fit values for both angles. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the dynamical behavior of a Carbon atom under the forces of the two fullerenes in the circular restricted three-body (CR3B) configuration with nanoscale. Here, we assume that the mass of a Carbon atom varies according to the Jeans law, and then with the use of Meshcherskii transformation, we determine the equations of motion and quasi-Jacobian integral. Then by the use of numerical values of the parameters, we investigate the potential surfaces, equilibrium points, regions of motion, Poincaré surfaces of sections, periodic orbits, basins of attraction and stability of the equilibrium points. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the properties of a five-dimensional Ricci-flat black hole within the framework of the Space–Time–Matter theory. By employing the Klein–Gordon equation, we derive the wave function equations for both the mass dimensional coordinate and the radial dimensional coordinate. We present the analytical solutions for the wave function on the mass dimensional coordinate under two distinct scenarios. Remarkably, we observe the absence of quantum effects on the mass dimensional coordinate, which aligns with the absence of a barrier in the wave function equation. For the radial component, we employ the B-spline method to numerically solve its wave function. Our findings reveal the existence of Hawking radiation between the event horizon and the cosmological horizon, with the transmission and reflection probabilities being determined by the presence of a barrier. Furthermore, we discover a significantly higher probability of particle detection near the cosmological horizon, while the probability near the event horizon approaches zero. [ABSTRACT FROM AUTHOR]

General theory of relativity can be equivalently formulated on a flat spacetime associating a torsion-free affine connection of non-vanishing non-metricity scalar Q. In this paper, we present an extension of this, viz., the f(Q) theory of gravity, and explore the early evolution of the universe in the background of anisotropic Bianchi-I model. The f(Q) theory in the current setting through its geometric modification is quite successful in explaining the late time accelerated expansion. Here, we note that it accommodates latest released constraints on the inflationary parameters by Planck’s collaboration group with excellent precession, but fails to produce a viable decelerated expansion in the radiation dominated era. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the results for the ground state of a Klein–Gordon oscillator under gravitational effects in a topologically charged Ellis–Bronnikov wormhole derived recently. We show that the authors failed to truncate a power-series and, consequently, could not obtain the desired solution to a differential equation. For this reason, their analytical expression for the ground-state eigenvalue is incorrect, a fact that affects all the conclusions drawn by the authors for the physical problem. [ABSTRACT FROM AUTHOR]

In this paper, we investigate how the electromagnetic field influences the idea of complexity within the framework of squared gravity. The physical traits, including heat dissipation, charge, anisotropic pressure, energy density variations and correction components are found to be significant contributors of complexity in celestial objects. By employing Herrera’s orthogonal splitting approach, scalar functions are obtained yielding a complexity factor that incorporates the crucial attributes of the self-gravitating system. Furthermore, we examine the dynamics of charged spherical configuration by considering homologous mode as the simplest evolutionary pattern. Our investigation includes complexity-free scenarios (dissipative/non-dissipative) with homologous constraints. Moreover, we explore the components that contribute toward complexity during the evolutionary process. We conclude that self-gravitating structures get more complex with the inclusion of extra curvature terms of squared gravity and charge. [ABSTRACT FROM AUTHOR]

In this paper, we introduce and characterize a pseudo-generalized Ricci-recurrent spacetimes and produce an example to verify the existence of such a spacetime. Then we demonstrate that a conformally flat generalized Ricci-recurrent spacetime with certain condition is a pseudo quasi-Einstein spacetime. Besides, it is proved that a pseudo-generalized Ricci-recurrent generalized Robertson–Walker spacetime represents a perfect fluid spacetime. Lastly, we study the impact of this spacetime under f (ℛ , T 2) and f (ℛ ∗) gravity scenario and deduce several energy conditions. [ABSTRACT FROM AUTHOR]

In this paper, we present a new method for searching maximally eight-qubit entangled states. Using 8-tangle and phase parameter orthogonal arrays, we can easily search maximally eight-qubit entangled states and obtain two new forms of maximally entangled eight-qubit states. We find that 8-tangle equaling zero is a necessary condition of maximally eight-qubit entangled states. [ABSTRACT FROM AUTHOR]

In this paper, we will analyze the relationship between both potentials in vacuum electrodynamics and their local gauge transformations. [ABSTRACT FROM AUTHOR]

Alcubierre's warp-drive was the first to introduce superluminal travel from different approaches. Instead of creating a shortcut through spacetime via a wormhole, geometrodynamics of simultaneously contracting and expanding spacetime were conjectured. However, both methods require exotic matter that violates energy conditions. In this paper, we employ the concept of braneworld that naturally influences spacetime geometrodynamics. Starting from defining and developing the spacetime metric of the braneworld warp bubble, the expression for energy densities as a function of relevant parameters which contributes to the braneworld approach of superluminal travel by hyperspace-drive was derived. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to obtain physically stable stellar models coupled with anisotropic matter distribution in the context of f (ℛ , T 2) theory. For this, we consider a static spherical geometry and formulate modified field equations containing various unknowns such as matter determinants and metric potentials. We then obtain a unique solution to these equations by employing Durgapal–Fuloria ansatz possessing a constant doublet. We also use matching criteria to calculate the values of these constants by considering the Schwarzschild exterior spacetime. Two different viable models of this modified theory are adopted to analyze the behavior of effective matter variables, anisotropy, energy conditions, compactness and redshift in the interiors of Her X-1, PSR J0348-0432, LMC X-4, SMC X-1, Cen X-3, and SAX J 1808.4-3658 star candidates. We also check the stability of these models by using three different physical tests. It is concluded that our considered stars satisfy all the physical requirements and are stable in this modified gravity for the considered parametric values. [ABSTRACT FROM AUTHOR]

The dark energy star is a hypothetical model proposed as an alternative to address problems related to the structure of black holes (BHs), such as the presence of singularities. While dark energy star models have been previously explored, their application to BHs remains unexplored. This paper aims to investigate the concept of dark energy stars and compare their properties to BHs. The primary objective is to explore the physical profiles of dark energy stars and evaluate their similarity to the physical properties of BHs described by the Schwarzschild solution. To achieve this, specific properties of the dark energy star models need to be satisfied in the context of BHs, and their physical profiles are studied. The metric function g r r proposed by M. R. Finch and J. E. F. Skea [Class. Quantum Grav. 6, 467 (1989)], as adopted by A. Banerjee, M. K. Jasim and A. Pradhan [Mod. Phys. Lett. A 35, 2050071 (2020), arXiv:1911.09546 [gr-qc]], is used and parametrized, making it close to BH spacetimes. The findings show that the model exhibits properties similar to BHs in terms of the stellar radius, compactness, surface redshift, and nature of gravity. Specifically, the dark energy star model behaves like BHs with a dark energy parameter ω = − 1 ∕ 3 , satisfying all energy conditions. However, it should be noted that the investigation is limited to static spherically symmetric cases and further studies are required to explore the model in rotating cases. Overall, this study sheds light on the potential of dark energy star models in explaining BH properties and presents promising avenues for further research in understanding the nature of BHs and dark energy. [ABSTRACT FROM AUTHOR]

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 τ → 3 μ  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. [ABSTRACT FROM AUTHOR]

This paper investigates the static spherically symmetric vacuum solutions of Brans–Dicke Theory of Gravity. In this paper, we systematically derive the static spherically symmetric solutions by starting with the general static spherically symmetric anzats, discovering the nonzero Christoffel symbols, nonzero Ricci tensor components and the Ricci Scalar. These results allow us to rewrite the four Brans–Dicke gravitational field equations explicitly in terms of the metric components, the scalar field and its scalar potential. This paper systematically explains and shows how to modify these linear second-order ordinary differential equations in order to be able to find the solution of the scalar field, the metric components and the scalar potential analytically. We successfully find the most general solution of the static spherically symmetric vacuum solutions of Brans–Dicke gravity and the well-known Schwarzschild solution is recovered as the simplest solution. [ABSTRACT FROM AUTHOR]

Lots of ready quantum private comparison (QPC) protocols usually only judge whether two users' data are equal, whereas the quantum private magnitude comparison (QPMC) protocol can compare the magnitude of two numbers, whose results are greater than, equal and less than. It is by announcing a comparison result of two bits in two data that the existent QPMC protocols determine the size relationships of the whole data. Although the announcement leaks no information to outside attackers, yet it alerts two participants to know each other's value of a certain bit. This is termed as bit leakage in this paper. In order to remedy this shortage, the paper proposes a novel QPMC protocol using a type of Bell state. The protocol is thoroughly analyzed, correct and secure. Also, it proves free of bit leakage. Additionally, because it is easier to implement because of the usage of a type of Bell state, it counts as a better alternative for QPMC. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This paper puts forward a novel quantum dialogue (QD) protocol without information leakage based on single photons in both polarization and spatial-mode degrees of freedom. In this protocol, the receiver sends his private message to the sender in the way of quantum secure direct communication; and the receiver decodes out the private message of the sender with the help of auxiliary single photons in two degrees of freedom, double controlled-not (CNOT) operations and an auxiliary classical bit sequence sent from the sender. As a result, no information leakage takes place. Moreover, this protocol is proven to defeat the intercept-resend attack, the measure-resend attack, the entangle-measure attack and the Trojan horse attack from an outside eavesdropper. This protocol only employs single photons in two degrees of freedom as quantum resource and needs single-photon measurements. The qubit efficiency of this protocol is as high as 66.7%. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this paper, the basic Einstein–Hilbert cosmological model is extended by adding a new functional F (G , T μ ν T μ ν) in the fundamental action, encoding specific geometrical effects due to a nontrivial coupling with the Gauss–Bonnet invariant (G), and the energy–momentum squared term ( T μ ν T μ ν ). After obtaining the corresponding gravitational field equations for the specific decomposition where F (G , T μ ν T μ ν) = f (G) + g (T μ ν T μ ν) , we have explored the physical features of the cosmological model by considering the linear stability theory, an important analytical tool in the cosmological theory which can reveal the dynamical characteristics of the phase space. The analytical exploration of the corresponding phase space structure revealed that the present model can represent a viable dark energy model, with various stationary points where the effective equation of state corresponds to a de-Sitter epoch, possible explaining the early and late time acceleration of the Universe. [ABSTRACT FROM AUTHOR]

In this paper, we study the 2D Euler equations for Chaplygin gas, which is a model for dark energy of the universe in some of cosmology theories. By using an ansatz developed by Yuen, we present some rotational and self-similar analytical solutions. We obtain the global existence of the constructed solutions and investigate the qualitative properties of the gas density according to various parameters. [ABSTRACT FROM AUTHOR]

In this paper, we study the one-parameter κ -generalized oscillator algebra κ (which includes the case of the standard Weyl–Heisenberg algebra). This algebra admits representations of finite-dimensional for negative values of the parameter κ. We construct the associated Perelomov like coherent states. We discuss their statistical properties. In particular, we derive the expressions of the Mandel parameter and Husimi function and we discuss the squeezing of the κ coherent states. [ABSTRACT FROM AUTHOR]

Recent advances in applying thermodynamic ideas to quantum systems have raised the novel prospect of using non-thermal, non-classical sources of energy, of purely quantum origin, like quantum statistics, to extract mechanical work in macroscopic quantum systems like Bose–Einstein condensates. On the other hand, thermodynamic ideas have also been applied to small systems like single molecules and quantum dots. In this paper, we study the quantum thermodynamics of small systems of anyons, with specific emphasis on the quantum Otto engine which uses, as its working medium, just one or two anyons. Formulae are derived for the efficiency of the Otto engine as a function of the statistics parameter. [ABSTRACT FROM AUTHOR]

Quantum coherence is an important feature that distinguishes quantum mechanics from classical physics. In this paper, we study the coherence of a quantum state with respect to a quantum channel, and introduce a coherence measure in terms of the generalized Wigner–Yanase–Dyson skew information. The basic properties and operational significance of the measure are expounded in detail, which shows that it is indeed a veritable quantity and satisfies many desirable conditions intuitively required for the coherence measures. We illustrate the significance of characterizing channels from the coherence perspective through some examples. Finally, we consider the average coherence of a state based on the generalized Wigner–Yanase–Dyson skew information with respect to any complete mutually unbiased bases in prime power dimensional systems, as well as with respect to all orthonormal bases, and show that these two averages are equivalent since they both can be seen as the coherence of the quantum state with respect to the depolarizing quantum channel. [ABSTRACT FROM AUTHOR]

The Mössbauer rotor effect recently gained a renewed interest due to the discovery and explanation of an additional effect of clock synchronization which has been missed for about 50 years, i.e. starting from a famous book of Pauli, till some more recent experimental analyses. The theoretical explanation of such an additional effect is due to some recent papers in the general relativistic framework. Here, we show that the additional effect of clock synchronization can be calculated in another way via the third postulate of relativity. [ABSTRACT FROM AUTHOR]

The Parisi–Wu scheme of quantization opens up the possibility of using anomalous fermionic gauge theories. An analysis of ultra-violet divergences reveals that the structure of counter terms is different from what is expected in conventional quantization schemes. In this paper, it is argued that there exists a possible mechanism of CP violation that requires at least three generations of quarks, a result well known from a phenomenological analysis of mass mixing of quarks. A few observations on possible ways of going beyond the Standard Model are included. [ABSTRACT FROM AUTHOR]

In this paper, we study two-point correlation function in a medium composed of two kinds of matter, which is the dual of a three-dimensional generalized p-brane gas geometry. Following the holographic prescription, we calculate temporal and spatial two-point functions in the medium. In general, the screening effect of the medium makes two-point functions decreases more rapidly than the CFTs two-point function. In the extremal limit, however, we find that a temporal two-point function is still conformal. This indicates that a two-dimensional UV CFT flows into a one-dimensional quantum mechanics in the IR limit. This is consistent with the fact that the near horizon geometry in the extremal limit reduces to AdS2. We also investigate holographic mutual information representing the correlation between two subsystems. We show that a critical distance in the IR region, where the mutual information vanishes, leads to a similar behavior to the correlation length of a two-point function. [ABSTRACT FROM AUTHOR]

Einstein–Podolsky–Rosen steering is a form of inseparable quantum correlations that exhibits an inherent asymmetric property, i.e. one-way steering. In this paper, we show that the radiation pressure effect can be profitably exploited to generate stationary Gaussian quantum steering between an optical cavity mode and a mechanical mode. The optical mode is driven by a blue-detuned laser within the unresolved sideband regime. Under realistic experimental conditions, we show that strong asymmetric steering can be generated between the two considered modes. Besides, we show that the direction of one-way steering can be controlled by varying the physical parameters of the system at hand (coupling, dissipation, and detuning). Also, we discuss how the generated steering can be estimated experimentally. The demonstrated optomechanical steering may have practical implications for asymmetric quantum information tasks, e.g. one-sided device-independent quantum key distribution and quantum teleportation. [ABSTRACT FROM AUTHOR]

In this paper, we study an isotropic and homogeneous Friedmann–Lemaitre–Robertson–Walker cosmological model in Weyl type f (Q , T) gravity with a dynamic deceleration parameter. The solution of the field equations is found using a variable deceleration parameter, viz., q = n + m H , with q the deceleration parameter, n and m constants, and H the Hubble parameter [Tiwari et al., Eur. Phys. J. Plus 132, 1 (2017)]. Then we calculate the values of the model parameters that are most likely to accord with the most recent observational data sets. We make use of the 57 CC points, SN and BAO datasets. We have contracted a graphical representation of the dynamical behavior of the cosmological parameters (the Hubble parameter, the deceleration parameter, the energy density and the equation of state) in terms of the redshift. To investigate the various eras of the universe, the evolution of the statefinder trajectory pairs (s , r) and (q , r) are studied. It is shown that the main energy component of the model is ordinary matter, which behaves initially as the SCDM model and then later as a fluid resembling quintessence, which behaves as the well-known Λ CDM model. A suitable cosmological model is constructed after analyzing the physical parameters of the model, the O m (z) diagnostic analysis. [ABSTRACT FROM AUTHOR]

In this paper, we study the quantum mechanical behavior of a deformed bare optomechanical oscillator interacting with a heat bath. This statistical study takes into account the temperature effect and the time dependency. Many material realizations can be inspired from our work during the experimental process to adjust many physical parameter values to have the right mechanical sensitivity of these materials. [ABSTRACT FROM AUTHOR]

In this paper, we discuss Klein–Gordon (KG) oscillators in the (1 + 2) -dimensional Gürses spacetime and under position-dependent mass (PDM) settings. We observe that the KG Gürses oscillators are introduced as a byproduct of the very nature of the Gürses spacetime structure. We report that the energy levels of such KG Gürses oscillators admit vorticity–energy correlations as well as spacetime-associated degeneracies (STADs). Moreover, we introduce a new set of KG pseudo-Gürses oscillators that admits isospectrality and invariance with the KG Gürses oscillators and inherits the same vorticity–energy correlations as well as STADs. [ABSTRACT FROM AUTHOR]

For black holes with more than one horizon, the existence of a global temperature is not fully understood. This can affect the thermodynamics of these black holes to be unclear. In this paper, using the method of quantum tunneling, we find a global temperature for asymptotically AdS multi-horizon black holes appeared in three-dimensional quasitopological gravities given by T H = κ eff / 2 π , in which the effective surface gravity is related to the surface gravity of each horizon. We also find a global temperature for the asymptotically warped AdS3 black holes, having the same expression as the AdS multi-horizon black holes. In all of the cases the global temperature differs from the conventional Hawking temperature. [ABSTRACT FROM AUTHOR]

With the popularization of E-payment, more and more electronic payment protocols have been proposed. In 2021, Lin et al. proposed a trusted third-party E-Payment protocol based on a set of three-particle local indistinguishable orthogonal product (X-LIOP) states. In this paper, we first point out that there is a security flaw where the merchant can forge the purchase goods information to sell something that the customer does not want to buy in Lin et al. protocol. Besides, the X-LIOP states used by Lin are not orthogonal and can be discriminated by Local Operation and Classical Communication (LOCC). Second, we propose a new electronic payment protocol that combines group signature and the three-particle X-LIOP states. Compared with Lin et al. protocol, customers can purchase goods anonymously in our protocol and the unforgeability of messages and signatures is guaranteed. [ABSTRACT FROM AUTHOR]

This paper is dedicated to the precise computation of anisotropic extensions for the Tolman IV solution. These extensions are achieved through the utilization of the extended gravitational decoupling scheme within the framework of f (R , T 2) gravity, where R is the Ricci scalar and T 2 is the contraction of energy–momentum tensor. In this context, we select a linear model characterized by the expression f (R , T 2) = R + ξ T 2 , where the parameter ξ establishes a connection between the geometric and matter components. The extended gravitational decoupling technique incorporates a decoupling parameter that governs the extent of the induced anisotropy. Deformations in the radial and temporal metric components lead to the decomposition of the field equations into two distinct subsystems. One of these sets pertains to the isotropic solution, while the other is addressed by implementing the extra constraints. We examine the outcomes through graphical analysis and investigate the viability and stability of the obtained anisotropic solutions for the celestial object. Moreover, we study the mass, compactness and surface redshift of the system to gain a comprehensive understanding of its characteristics. It is concluded that this technique in this modified gravity yields physically acceptable solutions. [ABSTRACT FROM AUTHOR]

This paper deals with the thermodynamics of gravitational radiation arising from the Bondi-Sachs space-time. The equation of state found allows us to conclude that the dependence of the energy density on the temperature is a quadratic power of the latter. Such a conclusion is possible once the consequences of the first law of thermodynamics are analyzed. Then, in analogy to electromagnetic radiation, the same approach used by Planck to obtain the quantum of energy of the gravitational radiation is proposed. An energy for the graviton proportional to the cubic frequency is found. The graviton is here understood as the quantum of gravitational energy. [ABSTRACT FROM AUTHOR]

In this paper, generalized Friedmann–Robertson–Walker universe for Strange Quark Matter (SQM) and Normal Matter (NM) coupled with Domain Wall (DW) in form perfect fluid have been investigated in f (R , T) modified theory. f (R , T) function has been assumed as f (R , T) = R + μ T and Modified Field Equations (MEFEs) have been attained. The MEFEs of the constructed model do not allow solutions of open and closed FRW universe. Obtained modified field equations of higher dimensional flat FRW universe have been solved by using Linearly Varying Deceleration Parameter (LVDP) suggested by Akarsu and Dereli [Int. J. Theor. Phys. 51, 612 (2012)]. Pressure and energy density of the matter distributions for the Linearly Expansion Model (LEM) and Constant Expansion Model (CEM) have been attained as decreasing values by the cosmic time t and constant μ in f (R , T) gravity. But for the Exponential Expansion Model (XEM), these quantities have been obtained as time-independent. It is found out that the domain wall behaves like invisible matter when s 1 = 0 due to negative domain wall tension ( σ w LSQM = − B c ) for SQM with DW of LEM. Strange quark matters for LDW and CDW models behave like cold dark matter when s 1 = 0 and s 3 = 0 , respectively. One can say that SQM with DW for LEM and CEM may cause the expansion of the universe in these special situations. Also, solutions of XEM have shown that domain wall matter behaves like stiff matter when μ = 2 0 π. All solutions of the constructed model in f (R , T) theory have been reduced to General Relativity (GR) theory solutions by assuming μ = 0. Finally, all solutions obtained have been discussed in detail. [ABSTRACT FROM AUTHOR]

The 2 6 Mg (n , γ) 2 7 Mg reaction plays a crucial role in the process of nucleosynthesis in stars. It occurs primarily in massive stars during their late evolutionary stages or during explosive events like supernovae. This paper focuses on investigating discrepancies in the ANC values of the 2 6 Mg (n , γ) 2 7 Mg reaction by analyzing experimental angular distributions of 2 6 Mg (d , p) 2 7 Mg using the DWBA, ADWA and CDCC methods for both ground and first excited states. We then use a mirror nucleus procedure to extract information on the ANCs of the ground state 2 6 Si (p , γ) 2 7 P reaction. The Hauser–Feshbach formalism of the statistical Compound Nucleus (CN) model was applied in this study to perform a compound-nucleus analysis of the 2 6 Mg (d , p) 2 7 Mg reaction. The 2 6 Mg (d , p) 2 7 Mg reaction has almost fulfilled the condition of peripherality, which is necessary for understanding the magnitude of the direct reaction contribution. ANCs for the 2 7 Mg → 2 6 Mg + n virtual decay system were obtained. Moreover, according to charge symmetry of mirror nuclei, the square of proton ANC for a 2 7 P → 2 6 Si + p is determined and comparison between the values of the presented ANCs. [ABSTRACT FROM AUTHOR]

In this paper, we quantize the Friedberg–Lee–Pang–Ren (FLPR) model, using an admissible gauge condition, within the framework of modified Faddeev–Jackiw formalism. Further, we deduce the gauge symmetries and establish off-shell nilpotent and absolutely anti-commuting (anti-)BRST symmetries. We also show that the physical states of the theory are annihilated by the first class constraints which is consistent à la Dirac formalism. [ABSTRACT FROM AUTHOR]

In this paper, we propose a compositional approach to construct subspaces consisting entirely of r-uniform states, i.e. states with each reduction to r subsystems being maximally mixed. The approach generates new objects from old ones by combining encoding isometries of pure quantum error correcting codes with entangled multipartite states and subspaces. Such a scheme allows for construction of states in heterogeneous systems, i.e. those having unequal local dimensions. The presented methods can be also used to obtain new pure quantum error correcting codes from certain combinations of old ones. The approach is illustrated with various examples including constructions of 2-, 3-, 4- and 5-uniform subspaces. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the behavior of a scalar bosonic field within the backdrop of Eddington-inspired Born–Infeld gravity with a global monopole configuration. Additionally, we consider the presence of both scalar and vector potentials. To introduce the scalar potential, we perform a transformation on the mass term, replacing M 2 with (M + S) 2 . For the vector potential, we apply a minimal coupling scheme, transforming p μ → D μ ≡ (p μ − e A μ) within the relativistic Klein–Gordon equation. We opt for a harmonic oscillator scenario where the scalar and vector potentials are equal, i.e. S = V ∝ x 2 . Through this setup, we analytically solve the wave equation using the confluent Heun equation form. Subsequently, we delve into the quantum system in the absence of any potential, determining the permissible values for bound-state relativistic energy levels and the scalar field's wave function. Our analysis reveals that the energy levels and wave function are influenced by various parameters present in the eigenvalue expression. [ABSTRACT FROM AUTHOR]

In this paper, F (ν) cosmology is proposed for the accelerating universe with asymptotic de Sitter expansion in terms of Hankel function index ν. To some extent, both the initial expansion during early inflation and the current accelerated expansion can be studied with a vacuum cosmic fluid, i.e. Λ in the pure de Sitter phase. Observational data further support the notion of a quasi-vacuum fluid, rather than a pure vacuum, contributing to the quasi-de Sitter acceleration in both the early and late universe. By examining the asymptotic expansion of the Henkel function as an approximate solution of the Mukhanov–Sasaki equation, we seek a more detailed study of quasi-de Sitter solutions in cosmology containing vacuum-like fluid. [ABSTRACT FROM AUTHOR]

In this paper, we introduce the black brane solutions in anti-de Sitter (AdS) space in four-dimensional (4D) Einstein–Gauss–Bonnet–Yang–Mills theory in the presence of string cloud and quintessence. Shear viscosity to entropy density ratio is computed via fluid–gravity duality, as a transport coefficient for this model. [ABSTRACT FROM AUTHOR]

We know that space and time are treated almost equally in classical physics, but we also know that this is not the case for quantum mechanics. A quantum description of both space and time is important to really understand the quantum nature of reality. The Page–Wootters mechanism of quantum time is a promising starting point, according to which the evolution of the quantum system is described by the entanglement between it and quantum temporal degrees of freedom. In this paper, we consider a qubit clock that is entangled with a quantum system due to the Wigner rotation induced by Lorentz transformation. We study how this time-system entanglement depends on the rapidity of the Lorentz boost. We consider the case of a spin-1/2 particle with Gaussian momentum distribution as a concrete example. We also compare the time-system entanglement entropy with the spin-momentum entanglement entropy and find that the former is smaller than the latter. [ABSTRACT FROM AUTHOR]

In this paper, we briefly survey open questions in cosmology that either have been or could potentially be addressed with the help of the causal set theory approach to quantum gravity. Our discussion includes topics ranging from dark matter and dark energy to primordial quantum fluctuations and horizon entropy. By putting together all in one place, these cosmologically relevant directions of work within causal set theory, we hope to impart a bird's-eye view of this important research theme. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a novel model for collective-dephasing noise in d -dimensional space. After that, we construct a multi-particle entangled state to resist the given collective-dephasing noise. Based on the measurement laws of multi-particle entangled state under two different bases, we propose a multipartite quantum key agreement protocol. In this protocol, multiple participants would obtain d -dimensional secret key even if the quantum channel is influenced by collective-dephasing noise. The security analysis indicates that this protocol can resist both dishonest participant attack and the outsider attacks which include intercept-resend attack and entangle-measure attack. By comparing with the existing QKA protocols, it is clear that our protocol has greater universality from the perspective of dimensionality and number of participants. [ABSTRACT FROM AUTHOR]

In this paper, the complete discrimination system for the polynomial method is applied to solve the Wu–Zhang system, and all the possible exact solutions are obtained, these exact solutions can be applied to the exploration of nonlinear physical phenomena, the method in this paper is different from the existing literature studies on the Wu–Zhang equation. By taking different parameters, interesting graphs are plotted for all the obtained solutions. The results confirm that the proposed method is effective and can be used to solve a variety of nonlinear consistency time fractional partial differential equations. [ABSTRACT FROM AUTHOR]

In this paper, we have suggested that the late time expansion of the Universe is caused by the absorption of baby universes. This absorption leads to a modified Friedmann equation with one free parameter B replacing the cosmological constant. The late time cosmology is modified in such a way that one can obtain agreement with the measured values of the Hubble parameter H(z) for z between 0 and the value corresponding to the time of last scattering of CMB for a suitable choice of B. In this paper, we show that the modified Friedmann equation with this choice of B also describes well other aspects of the large-scale structure of the Universe. [ABSTRACT FROM AUTHOR]