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In this paper, we study the dynamic properties of spin–orbit coupling (SOC) hyperfine f =1 spinor antiferromagnetic Bose–Einstein condensates with the external magnetic field. The condensate is confined in a toroidal trap and the numerical results are obtained based on the multicomponent Gross–Pitaevskii equation. Our results show that, in the presence of SOC, the spin dynamics for zero magnetic field slows with an increase of radius of the torus. However, this process accelerates when the magnetic field is considered. In addition, in this case, the oscillation behavior is almost consistent with the considered maximum radius. In the absence of SOC, the periodicity of spin dynamics vanishes. We also compare the thermalization time for different magnetic fields and radii, which decreases considerably for nonzero magnetic fields with the increase of radius. Furthermore, our analysis suggests that for stronger magnetic field strength the density structure can be regulated. As a consequence, the condensate recovers from the necklace to an annular-shaped state. [ABSTRACT FROM AUTHOR]

In this paper, we consider higher dimensional charged black holes to study nonperturbative corrected thermodynamics. This correction is dominant when the black hole size decreases due to the Hawking radiation. The nonperturbative correction on the black hole entropy is proportional to the exponential of the original entropy with a negative sign. We calculate some thermodynamics quantities such as the internal Helmholtz free energies, and obtain the effect of the exponential correction. We study the first law of thermodynamics and investigate how it satisfies. We also study the stability of the black hole through specific heat analysis and investigate the possible phase transition. We find a second-order phase transition that is interpreted as the unstable/stable phase transition. Then, we find a first-order phase transition that makes it unstable. Hence, the final stage of the Reissner–Nordström black holes may be an unstable phase, which means that black hole evaporation at the quantum scale. It may be a cause that we never find a black hole in accelerators. [ABSTRACT FROM AUTHOR]

In this paper, we have considered the flat Friedmann-Lemaître-Robertson-Walker (FRW) model in the framework of f(R, ∇R) gravity. We have analyzed the significance of bulk viscosity in the f(R, ∇R) gravity model to study the expansion of the universe. We have considered two bulk viscosity parameterizations and the use of power-law cosmology to constrain the model parameters H0 and q. Using the Bayesian analysis and likelihood function in conjunction with the Markov Chain Monte Carlo method, we obtained the model parameters H 0 = 70. 76732 − 0.00088 + 0.00010 and q = − 0. 6478 − 0.000075 + 0.000091 . The behaviors of energy density, bulk viscous pressure, and the effective equation of the state parameter with redshift are investigated in detail. These features demonstrate that the bulk viscosity is a valid candidate for acquiring the negative pressure needed to effectively drive the expansion of the universe. To check the validity of the f(R, ∇R) model, we also analyze the behavior of energy conditions. The adiabatic squared speed of the sound is used to test the model's stability. The Om(z) diagnostic is used in the model to identify the quintessence and phantom regions. [ABSTRACT FROM AUTHOR]

Determining absolute electron impact ionization cross-sections for atoms and molecules, whether through experimental or theoretical means, poses a formidable challenge and is typically limited to a narrow selection of species. In this paper, by using measured cross-sections and polarizability data, it was obtained empirical scaling laws for total single ionization and non-dissociative single ionization cross-section maximum of neutral molecules by collisions with electrons. It is found that the total single ionization cross-sections scale linearly with the target electric static polarizability, while the non-dissociate cross-sections exhibit a saturation effect for large target polarizabilities. This saturation effect is interpreted as the increasing role of fragmentation with polarizability. [ABSTRACT FROM AUTHOR]

In this paper, we consider the formation of vortices in multilayer stacks of Bose–Einstein condensates with tilted dipoles by numerical simulations of the Gross–Pitaevskii equation. Different dependencies of critical rotation frequency (CRF) and optical lattice height, vortex number, and rotation frequency are studied, depending on the direction of the dipole axis and dipole strength. Our results show that the CRF in z = 0 is minimum. When the optical lattice height is gradually increased, the CRF decreases gradually. Reducing of dipole strength in anisotropic dipole–dipole interaction (DDI) favours the formation of vortices, and such decline in isotropic DDI hinders the creation of vortices. The reason for this difference is that the repulsive interaction is favorable and the attractive interaction is disadvantageous for the vortex formation. In addition, we study the first-order correlation function and focus on variation of coherence. For small rotation frequency, the break of coherence occurs earlier in the case of purely repulsive interaction. With an increase in rotation frequency, the coherence concurrently disappears in layer z = 2. Moreover, we also investigate the quenched dynamics, showing that the increase of angular momentum is induced by changing the direction of dipoles and in this process the vortex number remains unchanged. [ABSTRACT FROM AUTHOR]

Aim of this paper is to investigate an anisotropic locally rotationally symmetric (LRS) Bianchi type-I space–time in the context of the recently proposed f(Q, T) gravity, where Q is the non-metricity scalar and T is energy–momentum tensor. We have considered f(Q, T) = αQ + βT a linear form, where α and β are model parameters. We have analyzed the exact solution of LRS Bianchi type-I space–time by assuming relation between metric potential A = Bn, where n is arbitrary non-zero real number. To study the anisotropic nature of the dynamical dark energy, we assume that the skewness parameters are time dependent and n ≠ 1. We have constrained to our model by using observational Hubble dataset. Onwards, discussed the physical behavior of cosmological parameters such as energy density, pressure, EoS parameter, deceleration parameter and, Energy conditions. [ABSTRACT FROM AUTHOR]

In this paper, we consider Einstein–Hilbert gravity in the presence of cosmological constant and non-abelian nonlinear electromagnetic field of logarithmic type that is minimally coupled to gravity. First, black brane solution of this model is introduced and then color non-abelian DC conductivity is calculated for this solution by using AdS/conformal field theory (CFT) duality. Our result recovers the Yang–Mills model in λ → 0 limit. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the influence of the angular momentum of the charged particle around non-extremal and extremal charged Taub–NUT black holes on Lyapunov exponent, and find spatial regions where chaos bound is violated. The exponent is determined by the effective potential. When the particle's charge is fixed, circular orbits gradually move away from the event horizons with the angular momentum's increases. We find that the bound is always violated at a certain distance from the horizons when the angular momentum is greater than a certain value. Especially when the black holes' charges are small enough, the Lyapunov exponent's violation always exists for any value of the particle's angular momentum. [ABSTRACT FROM AUTHOR]

In this paper, I have investigated the two-body pure penguin decays of B 0 → K * 0 K ¯ * 0 and B s 0 → K * 0 K ¯ * 0 , that these were collected with the LHCb detector, and the branching fractions were measured to be B (B 0 → K * 0 K ¯ * 0) = (8.0 ± 0.9 ± 0.4) × 10 − 7 and B (B s 0 → K * 0 K ¯ * 0) = (10.8 ± 2.1 ± 1.5) × 10 − 6 . I have studied these decay modes within the framework of the factorization approach by using three different energy scales; while in calculating the amplitude of these decays, the multiplications of four vectors of the polarization vectors, such as (ε K ¯ * 0 · ε K * 0 ) , (ε K ¯ * 0 · p B (s) ) , and (ε K * 0 · p B (s) ) appear. These parameters have been calculated based on helicity amplitudes (A 0 , A + , A −) ; the results obtained for branching fractions in the μ = mb/2 scale are B (B 0 → K * 0 K ¯ * 0) = (7.1 ± 1.3) × 10 − 7 and B (B s 0 → K * 0 K ¯ * 0) = (10.2 ± 1.9) × 10 − 6 . I have also estimated the fractions of longitudinal polarizations in B 0 → K * 0 K ¯ * 0 and B s 0 → K * 0 K ¯ * 0 decay modes by considering the transverse amplitudes (A ⊥ , A ∥) ; at the μ = mb/2 scale the results are obtained to be f L (B 0 → K * 0 K ¯ * 0) = 0.519 ± 0.067 and f L (B s 0 → K * 0 K ¯ * 0) = 0.419 ± 0.054 , which are comparable to the experimental results, 0.724 ± 0.051 ± 0.016 and 0.694 ± 0.016 ± 0.012, respectively, reported by the LHCb collaboration. [ABSTRACT FROM AUTHOR]

In this paper, we have studied the bulk viscous fluid connected with string cosmological model in a higher dimensional (five dimensions) Bianchi type-III space–time in the framework of Lyra's manifold. To get the deterministic solution of the field equations, we assume two physically appropriate conditions: (i) θ in the model parameter that is proportional to the eigen value of σ 2 2 of the shear tensor σ i j and (ii) the periodic time-varying deceleration parameter q specified as q = mcos (kt) − 1, where m, k > 0. In this paper, we have studied the periodic time-varying behaviour of a few quantities, such as the deceleration parameter q, the energy density ρ, the proper pressure p, the string tension density λ, the total pressure p ¯ , the energy density for particle ρp, and the displacement vector β(t), and we have discussed the physical significance of these quantities. It has been found that in the early stages of the universe's evolution, string prevails over particles, whereas the universe is dominated by massive string at late time. It is also noted that the string phase of the cosmos does not vanish in the model since particle density is constantly positive throughout the universe's history. In normal gauge treatment, β(t) acts like cosmological constant (Λ), and the solutions are compatible with observations. For the stability analysis, we have investigated the nature of various energy conditions (ECs). The positive behaviour of DEC indicates the model's validation; on the other hand, SEC and WEC are violating, indicating the universe's accelerated expansion. [ABSTRACT FROM AUTHOR]

In this paper, we consider a one-loop thermal correction to the g-factors of the ground and low-lying excited states in atomic systems with one valence s electron. As an example, we carried out calculations for Rb and Cs atoms, where optical measurements of transition frequencies set the metrological level of accuracy. With the development of atomic systems as the most accurate tool for spectroscopic experiments, it has become increasingly important to improve the accuracy of measuring the electron g-factor, which is currently at10−12. The rapid progress in this field in recent years requires analysis not only of various relativistic, quantum electrodynamics, and other effects, but also theoretical studies of phenomena stimulated by the external thermal environment. We can expect that the thermal contribution to the g-factor calculated in our work may be of interest in the near future. [ABSTRACT FROM AUTHOR]

The motion of droplet on surface with discontinuous wetting gradient is of great importance for understanding lab-on-a-chip systems and other microfluidic devices. Different wetting gradients are known to be the main influencing factor in the droplet self-driven process, but the effect of different wall structures on the droplet migration process also deserves further investigation. In this paper, we analyze the self-driven process of liquid droplets on a local wetting gradient surface under microgravity conditions using front tracking method. The effects of different driving stripe lengths L Ι Ι x * , different restrictive stripe lengths L Ι Ι Ι y * , and different surface wetting gradients Δcos⁡ θ on the droplet migration process and droplet morphology are analyzed. A theoretical formula that can predict the lateral spreading length of droplets is also proposed. The results show that different driving stripe length L Ι Ι x * lengths and the wetting gradient Δcos θ have significant effects on the migration velocity of droplets, while different restrictive stripe length L Ι Ι Ι y * lengths have very significant effects on the final morphological characteristics of droplets. When restrictive stripe length L Ι Ι Ι y * ≥ 1 , the hindering effect generated by the restrictive region ΙΙΙ has more and more significant effects on the morphological structure of droplets in the migration process. When the correction factor ε = 0.735 in the prediction equation, the predicted value calculated by the theoretical equation has a good degree of similarity with the numerical simulation results. [ABSTRACT FROM AUTHOR]

In this paper, a quantitative investigation of the non-classical and quantum non-Gaussian characters of the photon-subtracted displaced Fock state | ψ 〉 = a k D (α) | n 〉 , where k is the number of photons subtracted and n is Fock parameter, is performed by using a collection of measures like Wigner logarithmic negativity, linear entropy potential, skew information-based measure, and relative entropy of quantum non-Gaussianity. It is noticed that the number of photons subtracted (k) changes the nonclassicality and quantum non-Gaussianity in a significant amount in the regime of small values of the displacement parameter, whereas the Fock parameter (n) presents a notable change in the large regime of the displacement parameter. In this respect, the role of the Fock parameter is found to be stronger as compared to the photon subtraction number. Finally, the Wigner function dynamics considering the effects of photon loss channel is used to show that the Wigner negativity can only be detected by highly efficient detectors. [ABSTRACT FROM AUTHOR]

The paper proposes a novel cosmological model based on a two-field scenario, where the two fields are independently coupled with a specific invariant, based on cubic contractions of the Riemann tensor. After obtaining the modified Friedmann equations and the specific Klein–Gordon relations, the investigation studies the corresponding physical features by adopting the linear stability theory in a quintom scenario case where the coupling functions and potential energies have an exponential behavior. The corresponding investigation revealed a high complexity of the phase space structure, with various stationary points which can explain different aspects in the evolution of our Universe, the matter dominated epoch, and the late time accelerated stage. The present model can represent a viable solution to the dark energy problem due to the high complexity of the phase space and the existence of the scaling solutions. [ABSTRACT FROM AUTHOR]

High-level electronic structure calculations were conducted for LiC molecule and compared to other theoretical results. The potential energy curves (PECs) for the 18 states originating from the first three dissociation channels of LiC molecule were calculated by the internally contracted multireference configuration interaction method. The spectral constants and vibrational energy levels are reported. The transition properties for the a2Π, b2Δ, c2Σ−, d2Σ+, and 22Π states are discussed. In addition, the spin-orbit coupling effects were taken into account in the electronic transition d2Σ+–a2Π. The b2Δ and c2Σ− states had radiative lifetimes of approximately 0.03–16.83 and 0.86–8.06 ms, respectively. The d2Σ+ and 22Π states had radiative lifetimes of approximately 1.94–64.83 and 0.31–16.59 µs, respectively. Between these transitions, the emissions from the d2Σ+–a2Π, 22Π–c2Σ−, 22Π–b2Δ, and 22Π–a2Π systems were strongest, while the emissions from the c2Σ−–a2Π, b2Δ–a2Π, and 22Π–d2Σ+ systems were weaker. The d2Σ+1/2 state had radiative lifetimes of approximately 3.75–29.81 µs. Among the spontaneous emissions of the transitions generated by the d2Σ+1/2 state, the emissions from the d2Σ+1/2–a2Π1/2 and d2Σ+1/2–a2Π3/2 systems were relatively strong and easily observed experimentally. The radiative lifetime variation law with the rotational quantum number for the d2Σ+1/2 state at rotational quantum number J ≤ 70 and vibrational quantum number ν ≤ 15 is also presented in this paper. In addition, almost all the strong emissions of the transitions were distributed in the infrared region. It is expected that the results of this study will serve as a helpful reference for future experimental and theoretical studies. [ABSTRACT FROM AUTHOR]

Galperin introduced an interesting method to learn the digits of π by counting the collisions of two billiard balls and a hard wall. This paper studies two quantum versions of the Galperin billiards. It is shown that the digits of π can be observed in the phase shifts of the quantum models. [ABSTRACT FROM AUTHOR]

The minimal length Generalized Uncertainty Principle (GUP) is a proposed theory based on the basic phenomenology of Quantum Gravity (QG) to study the effect of gravity in the quantum realm in a nonrelativistic way. In this paper, we study the GUP effect on anharmonic oscillator by the ladder operator and perturbation theory. Taking different orders of perturbation from the potential of anharmonic oscillator, the first and second order energy corrections and the first order correction of wavefunction have been derived. We have also studied the variation of energy spectrum in general harmonic and anharmonic oscillator in an undergraduate nonrelativistic approach. [ABSTRACT FROM AUTHOR]

In this paper, the cosmic expansion of the universe filled with viscous fluid has been discussed in Bianchi type-I space-time. To solve Einstein's field equations, a time-varying deceleration parameter, (q(t)) yields a time variable scale factor a (t) = [ sinh (α t) ] 1 n , with "α" and "n" are positive constants. We also consider a time-varying gravitational constant (G) via the formulation 8πG = G0am, where "G0" and "m" are positive constants. Further, based on the third constraint, two different viscous cosmological models, one by considering the perfect gas equation of state p = ωρ and the other by considering time-varying bulk viscosity coefficient (ξ(t)), have been constructed. It is mentioned here that this particular choice of scale factor generates a class of accelerating models for n < 1, while for n > 1, the transition of the universe from early deceleration to current acceleration takes place. An important feature of the models is decreasing dark energy candidate, i.e., cosmological constant (Λ) with time, fine-tuning with the results from recent supernovae Ia observations. The various physical parameters involved in the models have been discussed analytically and graphically and are found in good agreement with recent observations. For the physical acceptability of both the models, energy conditions are shown graphically. The models are found to be physically acceptable, particularly in identifying the universe's transition. We have discussed the statefinder and observed that all the trajectories indicate dark energy candidates as Chaplygin gas and quintessence for different constraints (α, n). We have also calculated the cosmographic parameters such as jerk, lerk, and maxout to analyze the physical behavior of the DE models. [ABSTRACT FROM AUTHOR]

In this paper, we studied a spatially homogeneous and anisotropic Bianchi type II space-time in the presence of matter and modified holographic Ricci dark energy in Barber's second self-creation theory of gravitation. We obtained exact solution of the field equations by assuming (i) a special law of variation of the mean Hubble parameter and (ii) the component σ 1 1 of the shear tensor σ i i is proportional to the expansion scalar in the model. Some physical and dynamical parameters were determined and their significant roles are discussed with respect to cosmic evolution of the universe. We observe that the model is consistent with modern cosmological observational data. [ABSTRACT FROM AUTHOR]

One can use the generalized uncertainty principle (GUP) to incorporate the minimum measurable length in quantum gravity. It may be interesting to have a minimal time interval as well as the minimal length in the relativistic version of quantum mechanics in the presence of the gravitational effects. In this paper, we considered a covariant version of the GUP to investigate the effects of both the minimal time and the minimal length. Using the covariant GUP, the energy–momentum dispersion relation was modified. Starting with the modified dispersion relation, the corrections to the wave function were obtained and the problems of the particle in a box and the hydrogen atom were revisited. Considering the minimal time may be an interesting new topic, which is not widely studied before. It may lead to new results that can open a new window into quantum gravity. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of initial conditions characterized by compressibility of turbulence on the changes in scalar such as density, temperature, and pressure within the framework of rapid distortion theory (RDT) in the case of non-isentropic turbulence. This study is a follow-up of the basic work carried out by A. Simone, G.N. Coleman and C. Cambon [J. Fluid Mech. 330, 307 (1997)] in the case of quasi-isentropic turbulence and the previous work of M. Riahi and T. Lili [Fluid Dyn. Res. 52, 025501 (2020)] in the case of non-isentropic turbulence. RDT was used to examine the behavior of the root mean square (rms) fluctuations of density, temperature, and pressure. The coupling between these rms quantities, the partition factor, and the polytropic coefficient was also studied. RDT equations were solved numerically using a code that solves directly evolution equations of two-point spectral correlations for compressible homogeneous sheared non-isentropic turbulence. The RDT analysis was carried out for various initial turbulent Mach numbers Mt0 ranging from 0.1 to 0.4, and the initial compressible turbulence is to be one of the three states concerning the fraction of kinetic energy χ0: solenoidal (χ0 = 0), mixed (χ0 = 0.6), and dilatational (χ0 = 1) (χ0 is the ratio of the initial dilatational kinetic energy to the initial total kinetic energy). It is shown from this study that the changes in scalars are strongly dependent on the initial conditions. Magnitudes and asymptotic values of rms thermodynamics fluctuations and correlations between these thermodynamics fluctuations depend of Mt0. For large times, the isentropic state of the flow is well observed whatever Mt0 and χ0. [ABSTRACT FROM AUTHOR]

In this paper, we study the generalized Klein–Gordon oscillator under the effects of the violation of Lorentz symmetry defined by a tensor field (KF)μναβ out of the standard model extension. We consider a possible scenario of Lorentz-violating with a Cornell-type potential form electric field and a linear magnetic field that contributes a harmonic-type central potential effects in the quantum motions of oscillator fields. The bound-state solutions of the wave equation using the parametric Nikiforov–Uvarov method by considering Coulomb- and Cornell-type potential form functions are obtained. We see that the eigenvalue solutions get modified by the Lorentz symmetry breaking effects in comparison to the Landau levels (without Lorentz-violation effects in flat space). [ABSTRACT FROM AUTHOR]

Inflation has presented solutions for a number of important cosmological problems while leaving some unanswered. In this paper, we present a new cosmological model based on the quantization of the zero-point field, which is consistent with empirical data, requires fewer assumptions, and presents answers to some of those unanswered questions. A comparison between standard cosmology and the theory presented in this paper is given herein. Vacuum energy density: The standard inflationary model needs both Hubble's constant and matter density to estimate the vacuum energy density, but new cosmological model needs only Hubble's constant. Non-vacuum energy density: The standard model cannot predict the non-vacuum energy density, but the new model can predict it using only Hubble's constant. Ratio of vacuum energy to total energy: The standard model cannot predict the ratio of vacuum energy to total energy, but the new model can predict it, without using Hubble's constant. Energy conservation: In the standard model, total energy is not conserved before inflation and at the time of the creation of the universe, but in the new model total energy is mathematically proved to be conserved from the beginning of the universe as net energy (including gravitational potential energy) is always zero. Flatness and homogeneity: The standard model requires an inflaton field with a specific potential energy distribution to explain it, but the new model does not need any such hypothetical field; the zero-point field is sufficient. [ABSTRACT FROM AUTHOR]

In this paper, we extend Shaposhnikov et al.'s parity violating the Einstein–Cartan–Holst action by adding to Holst term H, a Proca photon–torsion coupling χpt = 10−24 as computed by De Sabbata, Garcia de Andrade, and Sivaram. The strength of Holst term is obtained, in the case of early universe torsion as, T ∼ 1 MeV. The gravity part is the Planck mass product with the Holst term. The photon mass in this case yields m2γH ∼ 10−69 GeV4. Therefore, in this case, the photon interacts very weakly with spin-torsion matter in Einstein–Cartan (EC) gravity and the strength of the Maxwell–Proca–Holst interaction is much weaker than in the pure gravity sector. For dark photons, this situation changes drastically since a dark photon mass reaches 1.5 GeV, and from this mass and T = 10−3 GeV, one obtains a Maxwell–Proca–Holst strength of 10−6 GeV4, which is now comparable with the gravity sector. Dynamo mechanism competes with the chirality and dissipation by the handness of the magnetic field with respect to the torsion trace vector to regenerate the magnetic field decay. Bombacigno and Mantovani recently found a sign of the Immirzi parameter in the Holst–Nieh–Yan extension of EC gravity. Here, we also find torsion waves for the Immirzi inverse parameter in the sense that this divergence of torsion trace is porportional to the Immirzi field. [ABSTRACT FROM AUTHOR]

In general relativity, the energy density of the gravitational field is not well defined. However, for asymptotically flat spacetimes, various definitions for total mass of the system have been proposed. In this paper, eight masses are considered and it is shown that some of them correspond to the active gravitational mass while the others correspond to the inertial mass. For example, the ADM mass corresponds to the inertial mass, while the Møller mass corresponds to the active gravitational mass. In general, the inertial and active gravitational masses are not equal. If the spacetime is vacuum at large r, the Einstein equations force the inertial and active gravitational masses to be the same. The Einstein equations also force these masses to be the same if any matter that extends out to large r satisfies the weak, strong, or dominant energy condition. The contributions of the inertial and active gravitational masses to the gravitational redshift, the deflection of light, the Shapiro time delay, the precession of perihelia, and the motion of test bodies in the spacetime are also examined. [ABSTRACT FROM AUTHOR]

Chaotic motion of electrons causes a considerable decrease in gain and efficiency of free-electron lasers (FELs). In this paper, we study chaotic dynamics of electrons moving with relativistic velocity in a realizable (three-dimensional) quadrupole wiggler when the radial dependency of wiggler magnetic field is fully taken into account using time series, Poincaré surface-of-section maps, and Liapunov exponents. The electron beam is also considered to be realizable with Gaussian density profile and an ion channel is considered as a guiding device for the electron beam. We show that the chaotic behavior of electron motion is due to the nonlinearity of quadrupole wiggler magnetic field and the chaotic electron motion occurs at almost large radial distances in which the wiggler magnetic field is large. Also, we find that one can control the electron chaotic motion by using electron beam with Gaussian density rather than the electron beam with uniform density. Furthermore, we investigate the effect of ion channel and find that when the electrostatic force of ion channel overcomes the nonlinearity effect of quadrupole wiggler magnetic field and self-repulsive force arises from electron beam, the electron motion becomes non-chaotic. We also investigate the electron motion under Budker condition and show that the Budker condition cannot guarantee the electron motion becoming completely non-chaotic. [ABSTRACT FROM AUTHOR]

A new experiment for gravitational waves (GWs) detection is proposed. It is shown that the effect of GWs on sound waves (SWs) in a fluid is that GWs vary the pressure of the fluid as they pass through it. This variation can be found by analysing the gauge of the local observer. It is shown that one can, in principle, detect GWs through the proposed new experiment. The variation of the pressure of the fluid, which represents detected signals, is indeed much higher than the corresponding values of GW amplitudes. The examples of rotating neutron stars (NSs) and relic GWs are discussed. Remarkably, a comparison of the proposed new method with a previous paper of Singh et al. (New J. Phys.19, 073023 (2017). doi:10.1088/1367-2630/aa78cb) on a similar approach shows a possible improvement of the sensitivity concerning the potential detection of GWs. It must be emphasized that this proposed procedure may be difficult in practical experiments because of the presence of different types of noise. For this reason, a section of the paper is dedicated to the discussion of such noise. On the other hand, this paper must be considered as pioneering the new proposed approach. Thus, we hope that in future more precise studies of the noise that concerns the proposed new experiment will be done. [ABSTRACT FROM AUTHOR]

The degeneracy associated with dynamical symmetry of a potential can be identified in quantum mechanics, by solving the Schrödinger equation analytically, using the method of separation of variables in at least two different coordinate systems, and in classical mechanics by solving the Hamilton–Jacobi equation. In the present pedagogical review, the notion of separability and superintegrability of a potential, with profound implications, is discussed. In an earlier tutorial paper, we addressed the n2-fold degeneracy of the hydrogen atom using the Casimir operators corresponding to the SO(4) symmetry of the 1/r potential. The present paper is a sequel to that work, in which we solve the Schrödinger equation for the hydrogen atom using separation of variables in the parabolic coordinate systems. In doing so, we take the opportunity to revisit some excellent works on symmetry and degeneracy in classical and quantum physics, if only to draw attention to these insightful studies, which unfortunately miss even a mention in most undergraduate and even graduate level courses in quantum mechanics and atomic physics. [ABSTRACT FROM AUTHOR]

Using the solution generating techniques of Das and Chaudhuri (Pramana J. Phys. 40, 277 (1993); Pramana J. Phys. 58, 449 (2002)), static magnetovac solutions of Einstein–Maxwell equations in general relativity are constructed from the stationary gravitational soliton solutions of Einstein's field equations corresponding to a Kerr object. The techniques followed in the present paper have not been much used in the literature so far although the results are obtained in a straightforward way. The stationary gravitational two-soliton solutions of Einstein's field equations for a Kerr object are generated using the soliton technique of Belinskii and Zakharov (Sov. Phys. JETP 48, 985 (1978); Sov. Phys. JETP 50, 1 (1979)). In the next step, following the procedure of Das and Chaudhuri, mentioned above, static magnetovac solutions of Einstein–Maxwell field equations corresponding to the generated stationary two-soliton solutions of the Kerr object are constructed. The solutions are found to be well behaved at spatial infinity and contain monopole, dipole, and other higher mass multipoles. The mass and the dipole moment of the source are evaluated. It is shown that by redefining some constants appearing in the solutions, Bonnor's (Z. Phys. 190, 444 (1966)) magnetic dipole solutions are faithfully reproduced. [ABSTRACT FROM AUTHOR]

This paper was devoted to studying the structure of the photon spheres and time-like circular orbits in the magnetic Gauss–Bonnet black hole space–time. Herein, the relationship between the photon spheres, the time-like circular orbits, and the black hole horizons was analyzed. We found that the photon sphere curve of the black hole ends at the horizon curve of the extreme black hole. The outer photon sphere is unstable and the inner photon sphere is stable. However, given that there is physically no inner photon sphere of the black hole inside the event horizon, the black hole has only one unstable photon sphere. Specifically, compact massive objects have at most two photon spheres, i.e., stable and unstable. Moreover, the curve of extremal stable time-like circular orbits ends at the coincidence of the inner and outer photon spheres, whereas the inner time-like circular orbits cannot be inside the photon spheres. Therefore, the extremal stable time-like circular orbits become multivalued, which is related to the existence of the photon sphere. When the photon sphere exists, the extremal stable time-like circular orbits behave as the innermost stable circular orbits. When the photon sphere does not exist, the extremal stable time-like circular orbits have both an innermost stable circular orbit and an outermost stable circular orbit. [ABSTRACT FROM AUTHOR]

Loop quantum gravity is a physical theory that aims at unifying general relativity and quantum mechanics. It takes general relativity very seriously and modifies it via quantisation. General relativity describes gravity in terms of geometry; therefore, quantising such theory must be equivalent to quantising geometry and that is what loop quantum gravity does. This sounds like a mathematical task as well, thus, in this paper we will present the mathematics of loop quantum gravity. We will do it from a mathematician's point of view. This paper is intended to be an introduction to loop quantum gravity for postgraduate students of physics and mathematics. In this work we will restrict ourselves to the three-dimensional case. [ABSTRACT FROM AUTHOR]

An introduction is presented in which reports in the issue are discussed on topics including semiconductors, thin films and sensors.

Quantum state transition is the core content of quantum control. This paper presents a control scheme of the state evolution path based on feedback control and reverse engineering design. To achieve high-precision state transition, we first adopt a homodyne-based feedback control strategy to form a closed-loop system. Then, based on the idea of reverse engineering design, the state evolution path of the system is planned and designed by considering the influence of environment decoherence on the state evolution. Numerical simulation results show that the control pulse based on planning design can drive the system from any initial state to the desired target state, and the coherence of the system is effectively protected during state transition. [ABSTRACT FROM AUTHOR]

The article reports that the study "The effect of quasiparticle self-energy on Cd2Re2O7 superconductor," by F.S. Razavi, Y. Rohanizadegan, M. Hajialamdari, M. Reedyk, R.K. Kremer, and B. Mitrovic, has been selected for the Best Paper Award 2015 by the journal.

The article announces the best paper award in the "Canadian Journal of Physics" for 2014 that was given to the article "A review of imaging methods in analysis of works of art: Thermographic imaging method in art analysis" by D. Gavrilov et al.

Modern developments in nonequilibrium thermodynamics have significant implications for the origins of life. The reasons for this are closely related to a generalized version of the second law of thermodynamics recently found for entropy production during irreversible evolution of a given system such as self-replicating RNA. This paper is intended to serve as an introduction to these developments. [ABSTRACT FROM AUTHOR]

In this paper, the structural stability, electronic structure, and magnetic properties of single-layer honeycomb arsenic–phosphorus (AsP) nanoribbons are systematically investigated using density functional theory calculations. Zigzag AsP nanoribbons (ZNRs) possess magnetic moments on the edge atoms. In addition, the ferromagnetic and intraedge antiferromagnetic states of ZNRs can be randomly coupled because of their equal total energy and almost identical electronic band structures. Armchair AsP nanoribbons (ANRs) show clear edge reconstructions and are nonmagnetic. ZNRs and ANRs are indirect and direct semiconductors, respectively, and have significantly smaller bandgaps than that of two-dimensional single-layer AsP due to their edge states. More interestingly, when the edge atoms are saturated by hydrogen atoms, ZNRs change from an indirect bandgap to a direct bandgap. In addition, both the ZNRs and ANRs exhibit enlarged bandgaps and nonmagnetic ground states due to hydrogen saturation. This work indicates that AsP nanoribbons can possess quite different electronic structures from two-dimensional single-layer AsP, extending the application field of AsP nanostructures. [ABSTRACT FROM AUTHOR]

The article announces that researchers A.D. May, W.-K. Liu, F.R.W. McCourt and their colleagues have received the 2013 Best Paper Award from the "Canadian Journal of Physics."

In Amano's comment on Jensen's paper, we notice two important misconceptions: (i) Amano overlooks the fact that all features special for a linear molecule originate in the double degeneracy in the bending motion (i.e., in the fact that for a linear triatomic molecule, the description of the bending motion must necessarily also involve the rotation about the axis of least moment of inertia, the a axis, which becomes the molecular axis at equilibrium), and (ii) the expectation value generated from the wavefunction gives an "average" value of the relevant observable (coordinate); the expectation value can, in principle, be obtained experimentally as the average of very many repeated measurements of the observable. In our previous papers on this subject, in particular the paper by Jensen discussed here, we have attempted to explain our results as coherently and "pedagogically" as we can, starting with the fundamental principles of quantum mechanics, and we encourage interested readers to refer to our previous works on the subject. Thus, we maintain our assertion that the vibrationally averaged structure of a linear molecule is observed as being bent, as we have demonstrated previously from both theoretical and experimental viewpoints. [ABSTRACT FROM AUTHOR]

In our previous papers (Can. J. Phys. 91 (2013) 715; 92 (2014) 1405), we studied Rydberg states of systems consisting of a nucleus of charge Z, a muon, and an electron, both the muon and electron being in circular states. The studies of such quasimolecules μZe were motivated by numerous applications of muonic atoms and molecules, where one of the electrons is substituted by the heavier lepton μ–. We demonstrated that the muonic motion can represent a rapid subsystem, while the electronic motion can represent a slow subsystem. We showed that the spectral lines emitted by the muon in such systems experience a red shift compared to the corresponding spectral lines that would have been emitted by the muon in a muonic hydrogenic atom/ion. In the present paper, we also consider Rydberg states of quasimolecules μZe with Z > 1 (i.e., Rydberg states of muonic–electronic helium and helium-like ions). However, our current approach has important distinctions from our previous papers. The systems considered here are truly stable and the electron orbit is generally elliptical (although the relatively small influence of the electron on the muon is neglected). In our previous papers, the influence of the electron on the muon was taken into account; however, in the rotating frame used in our previous papers, the motion of the muon was only metastable (not truly stable), and furthermore, only circular orbits of the electron were considered in our previous paper. In the present paper, we show that the effective potential energy of the Rydberg electron is mathematically equivalent to the potential energy of a satellite moving around an oblate planet. Based on this, we demonstrate that the unperturbed orbital plane of the Rydberg electron undergoes simultaneously two different precessions: precession within the orbital plane and precession of the orbital plane around the axis of the muonic circular orbit. We provide analytical expressions for the frequencies of both precessions. The shape of the elliptical orbit of the Rydberg electron is not affected by the perturbation, which is the manifestation of the (approximate) conservation of the square of the angular momentum of the Rydberg electron. This means that the above physical systems have a higher than geometrical symmetry (also known as a hidden symmetry) which is a counterintuitive result of general physical interest. We note that the above problem of the motion of the Rydberg electron in muonic–electronic helium atoms or helium-like ions is mathematically equivalent to another problem from atomic physics: a hydrogen Rydberg atom in a linearly-polarized electric field of a high-frequency laser radiation. [ABSTRACT FROM AUTHOR]

We aim to derive a phenomenological approach to link the theories of anomalous transport governed by fractional calculus and stochastic theory with the conductivity behavior governed by the semi-empirical conductivity formalism involving Debye, Cole–Cole, Cole–Davidson, and Havriliak–Negami type conductivity equations. We want to determine the anomalous transport processes in the amorphous semiconductors and insulators by developing a theoretical approach over some mathematical instruments and methods. In this paper, we obtain an analytical expression for the average behavior of conductivity in complex or disordered media via the fractional-stochastic differential equation, the Fourier–Laplace transform, some natural boundary initial conditions, and familiar physical relations. We start with the stochastic equation of motion called the Langevin equation, develop its equivalent master equation called the Klein–Kramers or Fokker–Planck equation, and consider the time-fractional generalization of the master equation. Once we derive the fractional master equation, we then determine the expressions for the mean value of the variables or observables through some calculations and conditions. Finally, we use these expressions in the current density relation to obtain the average conductivity behavior. [ABSTRACT FROM AUTHOR]

This paper reports continuous wave (CW) laser-assisted synthesis of plasmonic aluminium nanoparticles (ANPs) by drastically reducing the laser power density from the existing 105 W/cm2 to 9 W/cm2 using a specially designed ultralow duty cycle chopper. The aluminium target is subjected to laser irradiation by keeping it in a liquid medium maintained at a specific temperature. The effect of chopping frequencies (F), temperatures (T), and surfactant-glucose (C) on the formation of ANPs are investigated through field emission scanning electron microscopic and UV-visible spectroscopic analyses. The energy required for the ejection of ANPs from the target is obtained from the optical source, thermal source, and the molecular collision due to convection current. The purity of the nanoparticle is determined from energy dispersive spectroscopic analysis. The analysis reveals that ANPs of sizes in the range 20–50 nm are formed when F = 30 Hz, T = 60 °C, and C = 18 mg/cc, exhibiting excellent ageing stability. The photoluminescence spectrum, power spectrum, and CIE analyses for the excitations at 350 nm and 390 nm indicate the emission to be blue, suggesting that it is a suitable fluorescence material for UV-plasmonics. [ABSTRACT FROM AUTHOR]

In this paper, we study the scattering and absorption cross sections of a Schwarzschild–anti-de Sitter black hole surrounded by quintessence. The critical values of the cosmological constant and the normalization factor are obtained. We describe the event horizons and the extremal condition of the black hole surrounded by quintessence. The effects of quintessence on the classical and semi-classical scattering cross sections have been estimated. Additionally, the absorption cross section is studied with the sinc approximation in the eikonal limit. We consider the quintessence state parameter in the particular cases ω = –2/3 and –1/2. [ABSTRACT FROM AUTHOR]

Recently gravitational and Nieh–Yan (NY) chiral anomalies have been obtained in Riemann–Cartan space–time (L.C. Garcia de Andrade. Class Quantum Grav. 38(6), 065005 (2021). doi:10.1088/1361-6382/abd25f), where electrodynamics is encoded in the metric geometry. In this paper we follow the same pathway by obtaining a class of deformed de Sitter metrics in teleparallelism. The existence of the unmagnetized de Sitter metric (DSMM) without axial anomalies is proved. Unified theories à la Einstein, Eddington, and Schroedinger, called modified de Sitter metrics, present some novel features. First, we show that a pure DSMM in T4 does not induce gravitational anomalies. This is a motivation to study modifications of DSMM. NY torsional anomaly in DSMM teleparallel T4 geometry is shown to vanish in all cases. Gravitational non-trivial anomalies are obtained from these metrics. Torsional anomaly, much used in condensed matter physics, does not vanish. From these deformed DSMM, we show that a dynamo equation with torsional gradient sources is valid from class III of the metrics but is torsionless sourced in class II. We show that in the gravitational anomaly of new deformed de Sitter metric one may cancel the gravitational anomaly, by a proper choice of the metric function. The axial anomaly is obtained for some metric deformation as well. A simple deformation leads to the existence of the NY density in the case of DSMM. This would be class IV of DSMM. [ABSTRACT FROM AUTHOR]

In this research paper we focus on presenting the local non-similar solutions for two-dimensional steady and mixed convective flow of electrically conducting Carreau nanofluid under the influence of Brownian motion and thermophoresis effects. This research paper also presents the new mass flux boundary condition of nanoparticles. The governing partial differential equations are converted into ordinary differential equations by using the local non-similar transformations called the Sparrow–Quack–Boerner local non-similar method. A numerical approach is used to investigate the local non-similar solutions of the entire problem. Outcomes for the skin friction and rate of heat and mass transfer have been obtained and discussed for parametric variations of the buoyancy parameter ξ, magnetic parameter M, Weissenberg number We, viscosity ratio parameter β*, Brownian motion parameter Nb, thermophoresis parameter Nt, Prandtl number Pr, and Schmidt number Sc. From the obtained results a considerable increase in the skin friction coefficient is observed with an increase in buoyancy parameter ξ. Also, ξ shows relative growth for the momentum and concentration profiles. [ABSTRACT FROM AUTHOR]

In this paper, we study the 9B and 9Be mirror nuclei with shell and cluster models. The modified Eckart plus Coulomb repulsive potentials are selected to describe the interaction between particles. By solving the Schrödinger equation, the exact solution of this equation is obtained by the parametric Nikiforov–Uvarov (PNU) method. The eigenvalues and wave function are calculated for 9B and 9Be. Our results are compared with experimental results, as well as results from other papers, and are in good agreement. [ABSTRACT FROM AUTHOR]

The article lists the co-chairpersons of the 25th International Conference on Amorphous and Nanocrystalline Semiconductors which took place in Toronto, Ontario in August 2013 including Safa Kasap, Andrei Sazonov and John Rowlands.

This paper mainly studied the thermocapillary migration of deformable droplets induced by periodic temperature boundary under microgravity conditions. The finite-difference/front-tracking (FD/FT) method was used to solve the Navier–Stokes equation coupled with the energy equation, and the continuum surface force (CSF) model was used to simplify the surface tension of the phase interface. The results showed that the maximum droplet migration velocity increased with the increase of temperature amplitude, and the droplet cycle period became shorter with the increase of temperature angular frequency. In the 1/4 cycle, the initial movement time of droplet decreased with the increase of temperature phase. If the phase was reversed, the initial movement direction of the droplet changed. With the increase of Reynolds number (Re), the droplet tended to maintain its motion inertia. [ABSTRACT FROM AUTHOR]