Weyl's Gauge Field and Its Behavior

Using a manifestly gauge-invariant Lagrangian density of a system in which a real scalar field (matter field) is interacting with itself and with Weyl's gauge field, we shall study equations of the real scalar field and of Weyl's gauge field, and discuss the self-interacting term of the real scalar field. For a special self-interacting term, we shall obtain an equation of only Weyl's gauge field which plays an important role in solving the equation of Weyl's gauge field interacting with the real scalar field. By making use of the above mentioned equation we shall obtain a rigorous solution for Weyl's gauge field. Next, combining the equation of only Weyl's gauge field with the condition in Weyl's gauge field that the length scale of any vector changes under parallel transfer, we shall obtain a nonlinear equation for the length scale of Weyl's gauge field, which may be important in mathematical physics and is shown to have meron-type solution. By making use of the same techniques being used above, we shall study solution of equation of gradient Weyl's gauge field and as a result, obtain a nonlinear equation of the same type as being found above. Finally we shall study relation between local gauge transformation and symmetric connection in space-time. As a result, we can partly make clear relation between the change in the measure of length scale of a vector due to an infinitesimal parallel transfer and the coefficients of affine connection of Weyl's geometry.     

Non-gravitating scalar field in the FRW background

We study interacting scalar field theory non-minimally coupled to gravity in the FRW background. We show that for a specific choice of interaction terms, the energy–momentum tensor of the scalar field ϕ vanishes, and as a result the scalar field does not gravitate. The naive space dependent solution to equations of motion gives rise to singular field profile. We carefully analyze the energy–momentum tensor for such a solution and show that the singularity of the solution gives a subtle contribution to the energy–momentum tensor. The space dependent solution therefore is not non-gravitating. Our conclusion is applicable to other space–time dependent non-gravitating solutions as well. We study hybrid inflation scenario in this model when purely time dependent non-gravitating field is coupled to another scalar field χ.     

Time-dependent molecular fields created by the interaction of an external electro-magnetic field with a molecular system: the derivation of the wave equations

This article continues a previous study (Int. J. Quantum Chem. 114, 1645 (2014)) in which is presented a theory that discusses the possibility to induce a novel field – to be called molecular field – via the interaction of an external electro-magnetic (EM) field and a molecular system. Assuming the molecular system is made up of two coupled adiabatic states the theory leads from three time-space curl equations and one time-space divergence equation to a set of decoupled wave equations usually encountered for fields. In the present study, wave equations are derived for an external field having two features: (1) the field intensity is relatively high enough; (2) the duration of the interaction is short enough.

For this situation, the study reveals that the just mentioned interaction creates two fields that coexist within a molecule: one is just a scalar EM field essentially identical to the external EM field and the other, a vectorial field, produced by the non-adiabatic coupling terms. In addition, we mention that the wave velocities related to these two fields are identical to the wave velocity, c, of the external EM field.     

Spin-peierls transition in anisotropic Heisenberg chains

We study spin-Peierls transition for anisotropic Heisenberg chains within mean field theory. We find that dimerization occurs in the absence of a magnetic field and when the field is smaller than a critical field H_c. The transition temperature is obtained as a function of anisotropy and magnetic field.     

Charged particle motion in an electromagnetic field on Kerr background geometry

In this paper we study the trajectories of charged particles in an electromagnetic field superimposed on the Kerr background. The electromagnetic fields considered are of two types: (i) a dipole magnetic field with an associated quadrupole electric field, (ii) a uniform magnetic field. The contribution of the background geometry to the electromagnetic field is taken through the solutions of Petterson and Wald respectively. The effective potential is studied in detail for ther-motion of the particles in the equatorial plane and the orbits are obtained. The most interesting aspect of the study is the illustration of the effect of inertial frame dragging due to the rotation of the central star. This appears through the existence of nongyrating bound orbits at and inside the ergo surface. The presence of the magnetic field seems to increase the range of stable orbits, as was found in a previous study involving the Schwarzschild background.     

Braneworld model of dark matter: structure formation

Following a previous work (García-Aspeitia in Gen Rel Grav 43:315–329, 2011), we further study the behavior of a real scalar field in a hidden brane in a configuration of two branes embedded in a five dimensional bulk. We find an expression for the equation of state for this scalar field in the visible brane in terms of the fields of the hidden one. Additionally, we investigated the perturbations produced by this scalar field in the visible brane with the aim to study their dynamical properties. Our results show that if the kinetic energy of the scalar field dominates during the early universe the perturbed scalar field could mimic the observed dynamics for the dark matter in the standard paradigm. Thus, the scalar field dark matter hypothesis in the context of braneworld theory could be an interesting alternative to the nature of dark matter in the Universe.     

Dilaton driven Hawking radiation in AdS2 black hole

A recent study shows that Hawking radiation of a massless scalar field does not appear on the two-dimensional AdS₂ black hole background. We shall study this issue by calculating absorption and reflection coefficients under dilaton coupling with the matter field. If the scalar field does not couple to the dilaton, then it is fully absorbed into the black hole without any outgoing mode. On the other hand, once it couples to the dilaton field, the outgoing mode of the massless scalar field exists, and the nontrivial Hawking radiation appears. Finally, we comment on this dilaton dependence of Hawking radiation in connection with a three-dimensional black hole.     

Formation of Annihilation-Cyclotron Lines in Strong Magnetic Fields Near Neutron Stars

We study cyclotron and polarization spectral features in magnetized vacuum at frequencies near the one-photon annihilation resonance in a subcritical magnetic field. On the basis of this study, we propose a new method for determination of the neutron-star magnetic field. Using the dipole-field model, we show that detection of the annihilation line in absorption and an additional line in emission at MeV energies is evidence of the existence of a magnetic field (2.8-3.6)· 10¹²G on the surface of a neutron star.     

脉冲磁场处理对碳纳米管掺杂MgB2线材临界电流密度的影响

对碳纳米管(CNT)掺杂MgB₂超导体磁场处理后的行为进行了研究. 结果表明，CNT掺杂MgB₂超导体经5T脉冲磁场处理后临界电流密度J_c(H)在低磁场下提高了2—3倍，高场下提高一个数量级以上，扫描电镜结果显示CNT沿着处理磁场方向规则排列并且成为MgB₂基体的形核中心和高效的磁通钉扎中心. 关键词： 2')" href="#">MgB₂ 碳纳米管 脉冲磁场处理     

Formation of N3+ in pulsed-laser stimulated field desorption of nitrogen from metal surfaces

In pulsed-laser stimulated field desorption of nitrogen from metal surfaces, a plenty of N₃⁺ can be detected. Here we present the result of a study of the field dependence and emitter material specificity of N₃⁺ formation in pulsed-laser stimulated field desorption. These ions are formed by field ionization of N₃ molecules which are thermally desorbed from their field adsorption states by laser pulse heating of the surface.     

Osteocytes exposed to far field of therapeutic ultrasound promotes osteogenic cellular activities in pre-osteoblasts through soluble factors

Low intensity pulsed ultrasound (LIPUS) was reported to accelerate the rate of fracture healing. When LIPUS is applied to fractures transcutaneously, bone tissues at different depths are exposed to different ultrasound fields. Measurement of LIPUS shows pressure variations in near field (nearby transducer); uniform profile was found beyond it (far field). Moreover, we have reported that the therapeutic effect of LIPUS is dependent on the axial distance of ultrasound beam in rat fracture model. However, the mechanisms of how different axial distances of LIPUS influence the mechanotransduction of bone cells are not understood. To understand the cellular mechanisms underlying far field LIPUS on enhanced fracture healing in rat model, the present study investigated the effect of ultrasound axial distances on (1) osteocyte, the mechanosensor, and (2) mechanotransduction between osteocyte and pre-osteoblast (bone-forming cell) through paracrine signaling. We hypothesized that far field LIPUS could enhance the osteogenic activities of osteoblasts via paracrine factors secreted from osteocytes. The objective of this study was to investigate the effect of axial distances of LIPUS on osteocytes and osteocyte–osteoblast mechanotransduction. In this study, LIPUS (plane; 2.2 cm in diameter, 1.5 MHz sine wave, I_SATA = 30 mW/cm²) was applied to osteocytes (mechanosensor) at three axial distances: 0 mm (near field), 60 mm (mid-near field) and 130 mm (far field). The conditioned medium of osteocytes (OCM) collected from these three groups were used to culture pre-osteoblasts (effector cell). In this study, (1) the direct effect of ultrasound fields on the mechanosensitivity of osteocytes; and (2) the osteogenic effect of different OCM treatments on pre-osteoblasts were assessed. The immunostaining results indicated the ultrasound beam at far field resulted in more β-catenin nuclear translocation in osteocytes than all other groups. This indicated that osteocytes could detect the acoustic differences of LIPUS at various axial distances. Furthermore, we found that the soluble factors secreted by far field LIPUS exposed osteocytes could further promote pre-osteoblasts cell migration, maturation (transition of cell proliferation into osteogenic differentiation), and matrix calcification. In summary, our results of this present study indicated that axial distance beyond near field could transmit ultrasound energy to osteocyte more efficiently. The LIPUS exposed osteocytes conveyed mechanical signals to pre-osteoblasts and regulated their osteogenic cellular activities via paracrine factors secretion. The soluble factors secreted by far field exposed osteocytes led to promotion in migration and maturation in pre-osteoblasts. This finding demonstrated the positive effects of far field LIPUS on stimulating osteocytes and promoting mechanotransduction between osteocytes and osteoblasts.     

Causal structure of the thermal propagator in real-time formalisms

Within the path-integral approach and the thermal field dynamics we study thefull equilibrium fermion propagator. We clarify its representation in terms of the proper selfenergy. As an example we examine a fermion field coupled to an external gauge field.     

On the axiomatic approach to quasi-classical field theory

We study the connection between quasi-classical field theory and axiomatic statements of the quantum field theory, Schwinger source theory, and the Lehmann-Symanzik-Zimmermann (LSZ) formalism. The classical Schwinger source is connected with the classical field; the LSZ R-function is connected with the quantum field operator. The axioms of the quantum field theory are written in the context of the quasi-classical expansion. In the considered approach, the stationary action principle and canonical commutation relations for field operators are obtained as corollaries and are not postulated as initial statements of the theory.     

Effect of variation of dielectric constant on the magnetic field modulation of exciplex luminescence

The effect of variation of dielectric constant on the relative magnetic field effect in singlet luminescence has been studied using a typical exciplex system at a saturating field. The study indicates strong specificity in the perturbation of the magnetic field effect by alcoholic solvents. In contrast to alcohols where relative singlet magnetic field effect is of the order of 2% only, the magnetic field effect in non-alcoholic medium reaches as high as 9%. Moreover, dielectric constant variation in alcohols yields curves which are distinctly different from those in non-alcoholic media. It turns out that this dependence of magnetic field effect on dielectric constant is similar in all non-alcoholic solvent mixtures. An analytical study based on Hong and Noolandi’s solution of Smoluchowski equation has been made. Derived expressions can interpret experimental curves reasonably well.     

The effect of a 7 T magnetic field on the egg hatching of Heliothis virescens

The effect of a strong magnetic field on the egg hatching of Heliothis virescens (Tobacco bugworm) in a 7 Tesla field was studied, and apparent biological effects of the magnetic field were observed. On average of three batches of eggs in this study, the hatching of the eggs in the 7 T field was delayed about 21.7 ± 0.9 h and the hatching rate was reduced to about 58 ± 8% compared to those of eggs in 1.4 Gauss field. No apparent effect of the 1600 Gauss fringe field of the 7 T magnet on the egg hatching of Heliothis virescens was observed.     

Micropillar resonator in a magnetic field: Zero and finite temperature cases

In this work, we present a theoretical study of a quantum dot–microcavity system which includes a constant magnetic field in the growth direction of the micropillar. First, we study the zero temperature case by means of a self-consistent procedure with a trial function composed of a coherent photon field and a BCS function for the electron–hole pairs. The dependence of the ground state energy on the magnetic field and the number of polaritons is found. We show that the magnetic field can be used as a control parameter for the photon number, and we make explicit the scaling of the total energy with the number of polaritons. Next, we study this problem at finite temperatures and obtain the scaling of the critical temperature with the number of polaritons.     

光场与级联三能级原子相互作用时的熵特性和薛定谔猫态

研究了光场与级联三能级原子相互作用时的熵特性,导出了场(原子)熵的计算公式,讨论了原子初始态和单光子失谐量对场(原子)熵的影响,借助于场的准概率分布Q函数,分析了场态的统计性质,结果表明,原子初始处于中能级时,光场将在t=12T_R(T_{R< /sub>为单光子回复周期)时出现薛定谔猫态. 关键词： 级联三能级原子 熵特性 薛定谔猫态}     

Non-minimal warm inflation and perturbations on the warped DGP brane with modified induced gravity

We construct a warm inflation model with inflaton field non-minimally coupled to induced gravity on a warped DGP brane. We incorporate possible modification of the induced gravity on the brane in the spirit of f(R)-gravity. We study cosmological perturbations in this setup. In the case of two field inflation such as warm inflation, usually entropy perturbations are generated. While it is expected that in the case of one field inflation these perturbations to be removed, we show that even in the absence of the radiation field, entropy perturbations are generated in our setup due to non-minimal coupling and modification of the induced gravity. We study the effect of dissipation on the inflation parameters of this extended braneworld scenario.     

Dynamics of neutralized charged particle beams in external magnetic and self fields

The dynamics of charged particle beams under the influence of their self-magnetic field and an external magnetic field is examined on the basis of equations for the trajectory of a boundary particle. A study is made of the change in the dynamics of fast particles due to the influence of the electric field of the partially neutralized space charge of the beam, the stationary electric field, and the field of the oscillations in the quasineutral beam plasma. Changes in the total beam energy caused by the self-electric field and in the longitudinal velocity owing to the self-magnetic field are taken into account. Zh. Tekh. Fiz. 68, 106–109 (August 1998)