Energy and spatial momentum of charged rotating frames in tetrad gravity

We compute the total energy and the spatial momentum of four charged rotating (Kerr-Newman) frames by using the gravitational energy-momentum 3-form within the framework of the tetrad formulation of the general relativity theory. We show how the effect of the inertial always makes the total energy divergent. We use a natural regularization method, which yields the physical value for the total energy of the system. We show how the regularization method works on a number of different rotating frames that are related to each other by the local Lorentz transformation. We also show that the inertial has no effect on the spatial momentum components.     

Energy and momentum of a spherically symmetric dilaton frame as regularized by teleparallel gravity

We calculate energy and momentum of a spherically symmetric dilaton frame using the gravitational energy‐momentum 3‐form within the tetrad formulation of general relativity (GR). The frame we use is characterized by an arbitrary function ? with the help of which all the previously found solutions can be reproduced. We show how the effect of inertia (which is mainly reproduced from ?) makes the total energy and momentum always different from the well known result when we use the Riemannian connection . On the other hand, when use is made of the covariant formulation of teleparallel gravity, which implies to take into account the pure gauge connection, teleparallel gravity always yields the physically relevant result for the energy and momentum.     

Energy and momentum of general spherically symmetric frames on the regularizing teleparallelism

In the context of the covariant teleparallel framework, we use the 2-form translational momentum to compute the total energy of two general spherically symmetric frames. The first one is characterized by an arbitrary function H(r), which preserves the spherical symmetry and reproduces all the previous solutions, while the other one is characterized by a parameter ξ which ensures the vanishing of the axial of trace of the torsion. We calculate the total energy by using two procedures, i.e., when the Weitzenböck connection Γ_α^β is trivial, and show how H(r) and ξ play the role of an inertia that leads the total energy to be unphysical. Therefore, we take into account Γ_α^β and show that although the space×we use contain an arbitrary function and one parameter, they have no effect on the form of the total energy and momentum as it should be.     

Pairing and the structure of the -shell nuclei

The influence of the isoscalar and isovector pairing components of the effective nucleon-nucleon interaction is evaluated for several isobaric chains, in the framework of full shell model calculations. We show that the combined effect of both isospin channels of the pairing force is responsible for the appearance of ground states in odd-odd nuclei. However, no evidence is found relating them to the Wigner energy. We study the dependence of their contributions to the total energy on the rotational frequency in the deformed nucleus Cr. Both decrease with increasing angular momentum and go to zero at the band termination. Below the backbending their net effect is a reduction of the moment of inertia, more than half of which comes from the proton-neutron channel.     

Turbulent equipartition and homogenization of plasma angular momentum

A physical model of turbulent equipartition (TEP) of plasma angular momentum is developed. We show that using a simple, model insensitive ansatz of conservation of total angular momentum, a TEP pinch of angular momentum can be obtained. We note that this term corresponds to a part of the pinch velocity previously calculated using quasilinear gyrokinetic theory. We observe that the nondiffusive TEP flux is inward, and therefore may explain the peakedness of the rotation profiles observed in certain experiments. Similar expressions for linear toroidal momentum and flow are computed and it is noted that there is an additional effect due the radial profile of moment of inertia density.     

Neutron Stars in Teleparallel Gravity

In this paper, we deal with neutron stars, which are described by a perfect fluid model, in the context of the teleparallel equivalent of general relativity. We use numerical computations (based on the RNS code) to find the relation between the angular momentum of the field and the angular momentum of the source. One such relation was established for each stable star resulting from the numerical computation with an equation of state, the central energy density, and the ratio between the polar and equatorial radii as input, the central energy density and the ratio between polar and equatorial radii. We also find a regime in which the relation between gravitational angular momentum and moment of inertia (as well as the angular velocity of the fluid) is linear. We give the spatial distribution of the gravitational energy and show that it depends linearly on the squared angular velocity of the source.     

Crust-core properties of neutron stars in the Nambu–Jona-Lasinio model

We adopt the Nambu–Jona-Lasinio(NJL) model to study the crust-core transition properties in neutron stars(NSs). For a given momentum cutoff and symmetry energy of saturation density in the NJL model, decreasing the slope of the symmetry energy gives rise to an increase in the crust-core transition density and transition pressure.Given the slope of the symmetry energy at saturation density, the transition density and corresponding transition pressure increase with increasing symmetry energy. The increasing trend between the fraction of the crustal moment of inertia and the slope of symmetry energy at saturation density indicates that a relatively large momentum cutoff of the NJL model is preferred. For a momentum cutoff of 500 Me V, the fraction of the crustal moment of inertia clearly increases with the slope of symmetry energy at saturation density. Thus, at the required fraction(7%) of the crustal moment of inertia, the NJL model with momentum cutoff of 500 Me V and a large slope of the symmetry energy of saturation density can give the upper limit of the mass of the Vela pulsar to be above 1.40 M_⊙.     

Rotating nuclei in a semiclassical description

A recently proposed semiclassical method for extracting the smoothly varying part of the total energy of an independent particle system is applied to a rotating system. Expressions for the average density distribution, angular momentum, total energy and effective moment of inertia are given.     

用于微型卫星姿态控制的高温超导动量轮

卫星或宇宙飞船在太空中需要精确定位,动量轮是卫星或宇宙飞船姿态控制的关键部件.每个宇宙飞船上有三个或四个动量轮,这些动量轮虽然体积小,但是其角动量占宇宙飞船总角动量的绝大部分.动量轮实质上就是电机的转子,它具有很高的转动惯量.在适当的时间,启动或停止三个电机就能够控制宇宙飞船的姿态.我们已经研制了一个小的动量轮模型,该模型重量轻、结构紧凑,而且能效高.动量轮模型的主要创新点是使用了高温超导磁悬浮轴承,因此,它具有摩擦力小,转速高,储存动量大的特点.动量轮模型的最大设计转速为15,000RPM,储存的角动量为3.5J*s-1.     

A study of the variable moment of inertia models

The variable moment of inertia (VMI) model proposed by Holmberg and Lipas has been shown to be a special case of the VMI model of Mariscottiet al. The solution of Mariscotti’s model is expressed in terms of hypergeometric functions, which directly give the rotational energies or their expansions in terms of the quantityF(F+1), whereF is the total angular momentum. The present way of looking at the VMI model also tells us how to write the general dependence of the vibrational energy and the moment of inertia on the energyE _J.     

Casimir effects: An optical approach II. Local observables and thermal corrections

We recently proposed a new approach to the Casimir effect based on classical ray optics (the “optical approximation”). In this paper we show how to use it to calculate the local observables of the field theory. In particular, we study the energy–momentum tensor and the Casimir pressure. We work three examples in detail: parallel plates, the Casimir pendulum and a sphere opposite a plate. We also show how to calculate thermal corrections, proving that the high temperature ‘classical limit’ is indeed valid for any smooth geometry.     

Physical picture behind the oscillating sign of drag in high Landau levels

We consider the oscillating sign of the drag resistivity and its anomalous temperature dependence discovered experimentally in a bilayer system in the regime of the integer quantum Hall effect. We attribute the oscillating sign to the effect of disorder on the relation between an adiabatic momentum transfer to an electron and the displacement of its position. While in the absence of any Landau level mixing a momentum transfer implies a displacement of (with being the magnetic length), Landau level mixing induced by short range disorder adds a potentially large displacement that depends on the electron's energy, with the sign being odd with respect to the distance of that energy from the center of the Landau level. We show how the oscillating sign of drag disappears when the disorder is smooth and when the electronic states are localized.     

两体相互作用费米系统在自旋轨道耦合和塞曼场中的基态转变

在超冷费米系统中实现人造规范势的突破,吸引了许多新问题的研究,展现了许多新奇的物理现象.本文研究了在环阱中,具有自旋轨道耦合和塞曼作用的两体相互作用费米模型.通过平面波展开的方法,解析求解了两体费米系统的本征能态.系统的总动量为守恒量,可以在不同总动量空间中研究能谱.研究发现:随着塞曼相互作用增大,在不同总动量空间,两体费米系统的本征能量均逐渐降低,系统基态从总动量为零空间转变到有限值空间.从吸引到排斥相互作用,无塞曼相互作用时,基态总动量始终为零,有塞曼相互作用时,基态总动量从零转变为有限值.通过单粒子和基态动量分布研究,本文直观地揭示了由塞曼能级劈裂引起的基态转变.     

热质的运动和传递——热子气的守恒方程和傅立叶定律

本文在热质和热子气概念的基础上建立了热子气的质量、动量、能量守恒方程.基于傅立叶导热定律求得了热子气粘性系数和粘性力的近似表达式.分析了傅立叶定律的物理意义:傅立叶定律是在忽略惯性力的条件下对热子气动量方程的近似.在极低温度或极高热流密度条件下傅立叶定律不再适用.     

Energy and Angular Momentum of Systems in General Relativity

Stemming from our energy localization hypothesis that energy in general relativity is localized in the regions of the energy-momentum tensor, we had devised a test with the classic Eddington spinning rod. Consistent with the localization hypothesis, we found that the Tolman energy integral did not change in the course of the motion. This implied that gravitational waves do not carry energy in vacuum, bringing into question the demand for the quantization of gravity. Also if information is conveyed by the waves, the traditional view that information transfer demands energy is challenged. Later, we showed that the body angular momentum changed at a rate indicating that the moment of inertia increased to higher order, contrary to traditional expectations. We consider the challenges facing the development of a localized expression for the total angular momentum of the body including the contribution from gravity. We find that Komar's expression does not lead to an adequate formulation of localized angular momentum.     

Decomposition of the total momentum in a linear dielectric into field and matter components

The long-standing resolution of the Abraham–Minkowski electromagnetic momentum controversy is predicated on a decomposition of the total momentum of a closed continuum electrodynamic system into separate field and matter components. Using a microscopic model of a simple linear dielectric, we derive Lagrangian equations of motion for the electric dipoles and show that the dielectric can be treated as a collection of stationary simple harmonic oscillators that are driven by the electric field and produce a polarization field in response. The macroscopic energy and momentum are defined in terms of the electric, magnetic, and polarization fields that travel through the dielectric together as a pulse of electromagnetic radiation. We conclude that both the macroscopic total energy and the macroscopic total momentum are entirely electromagnetic in nature for a simple linear dielectric in the absence of significant reflections.     

Rotational energy and limits to fusion reactions between two nuclei

The energy balance of the fusion process between two nuclei is discussed with respect to the rotational energy. Two energy regimes are obtained. In the first regime the increase of rotational energy of the compound system as function of incident energy is governed by the moment of inertia of the two-fragment system at the barrier configuration. The faster increase of rotational energy of the compound system is furnished by theQ-value. In a sliding collision only part of theQ-value can be converted into rotational energy. Therefore, the Yrast limit in the population of the compound nucleus cannot be reached. When this source of energy is exhausted at a certain angular momentum, a second regime is obtained; then the increase of angular momentum and rotational energy as function of incident energy must be determined by the moment of inertia of the compound system.     

Pseudotensors in asymptotically curvilinear coordinates

We show how to calculate pseudotensor-based conserved quantities for isolated systems in general relativity, in a way which allows an arbitrary asymptotic behavior of the coordinate system used. Our method is a generalization of that given by Persides [1], and allows the asymptotic evaluation of energy, momentum, and angular momentum in any coordinate system. We carry out the calculation for the Schutz-Sorkin gravitational Noether operator, which is a pseudotensorial operator on vector fields that reduces to the familiar pseudotensors for particular choices of the fields.     

Nonadiabatic Effect on the Rescattering Trajectories of Electrons in Strong Laser Field Ionization Process

The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17U_p and that of the final energy at 10U_P are obtained,based on the adiabatic approximation in which the initial momentum of the electron is assumed to be zero.We theoretically study the nonadiabatic effect by assuming a nonzero initial momentum on the rescattering trajectories based on the semiclassical simpleman model.We show that the nonzero initial momentum will modify both the maximal return energy at collision and the final energy after backward scattering,but in different ways for odd and even number of return trajectories.The energies are increased for even number of returns but are decreased for odd number of returns when the nonzero(positive or negative) initial momentum is applied.     

Linear chain structure of four-α clusters in 16O

We investigate the linear chain configurations of four-α clusters in 16O using a Skyrme cranked Hartree-Fock method and discuss the relationship between the stability of such states and angular momentum. We show the existence of a region of angular momentum (13-18?) where the linear chain configuration is stabilized. For the first time we demonstrate that stable exotic states with a large moment of inertia (?2/2Θ～0.06-0.08 MeV) can exist.