单极子荷电黑洞时空背景中有质量标量场的衰减

通过对在单极子荷电黑洞背景中有质量标量场后期演化的研究,发现振荡反幂函数的衰减方式支配了有质量标量场的后期衰减.有质量标量场在单极子荷电黑洞时空背景中的后期衰减比在无整体单极子的ReissnerNordstrm时空度规下的后期衰减更快     

Nonuniversality in Low-Volume-Fraction Ostwald Ripening

We study Ostwald ripening in the regime of small volume fraction and consider spatially periodic systems whose size is smaller than the screening length. Within the snapshot perspective we obtain an explicit characterization of the leading-order deviation to the classical mean-field theory by Lifshitz, Slyozov and Wagner (LSW). Using this representation, we show that the corrections are not universal, in the sense that the mean value has a strong dependence on geometry, and arbitrarily large fluctuations can happen with finite probability. AMS Subject classification: 35B27, 74N20, 82C26.     

Global Monopole in Kalb–Ramond Background

In recent, S. SenGupta and S. Sur [Phys. Lett. B 502 (2001) 350] have obtained static vacuum solutions of the gravitational field equations in back ground space time with torsion. The torsion is identified with the field strength of a second-rank anti-symmetric tensor field, namely Kalb-Ramond field. In this work, we present the solutions for the metric outside a monopole resulting from the breaking of a global 0(3) symmetry in Kalb-Ramond background. A comparison is made with the corresponding results predicted by general relativity.     

Finite-Range Electromagnetic Interaction and Magnetic Charges Spacetime Algebra or Algebra of Physical Space?

A finite-range electromagnetic (EM) theory containing both electric and magnetic charges constructed using two vector potentials A^μ and Z^μ is formulated in the spacetime algebra (STA) and in the algebra of the three-dimensional physical space (APS) formalisms. Lorentz, local gauge and EM duality invariances are discussed in detail in the APS formalism. Moreover, considerations about signature and dimensionality of spacetime are discussed. Finally, the two formulations are compared. STA and APS are equally powerful in formulating our model, but the presence of a global commuting unit pseudoscalar in the APS formulation and the consequent possibility of providing a geometric interpretation for the imaginary unit employed throughout physics lead us to prefer the APS approach.     

Information-Theoretic Features of Many Fermion Systems: An Exploration Based on Exactly Solvable Models

Finite quantum many fermion systems are essential for our current understanding of Nature. They are at the core of molecular, atomic, and nuclear physics. In recent years, the application of information and complexity measures to the study of diverse types of many-fermion systems has opened a line of research that elucidates new aspects of the structure and behavior of this class of physical systems. In this work we explore the main features of information and information-based complexity indicators in exactly soluble many-fermion models of the Lipkin kind. Models of this kind have been extremely useful in shedding light on the intricacies of quantum many body physics. Models of the Lipkin kind play, for finite systems, a role similar to the one played by the celebrated Hubbard model of solid state physics. We consider two many fermion systems and show how their differences can be best appreciated by recourse to information theoretic tools. We appeal to information measures as tools to compare the structural details of different fermion systems. We will discover that few fermion systems are endowed by a much larger complexity-degree than many fermion ones. The same happens with the coupling-constants strengths. Complexity augments as they decrease, without reaching zero. Also, the behavior of the two lowest lying energy states are crucial in evaluating the system’s complexity.     

电单极子和磁单极子的统一模型

证明磁单极子和电单极子可以在Hopf丛(S³=S²×S¹)的基础上统一生成,该丛有结构群U(1).它在底流形S²上的联络可以分为电单极型和磁单极型两类.磁荷有量子化条件而电单极子就是磁量子数n=0时的解.这样,电单极子和磁单极子在理论上具有同一性.它们是同一事物的两种不同的形态.通过映射的伦移引入时间坐标,从而使电单极子成为Minkowski空间中的一个〈活化〉的模型.它具有Lorentz变换下的不变性.     

相对论核多体理论中的自洽问题和求和规则

着重讨论了建立在相对论平均场基态上的相对论无规位相近似的自洽处理 .自洽处理要求基态和巨共振激发态的研究从同一个拉氏量出发,采用同一种建立在相对论下的完备基上的近似 .同时也讨论了自洽条件下Dirac海核子态的作用 ,指出 Dirac海核子态的贡献不能忽略 ,特别是在核的巨单极共振的情况.用约束的相对论平均场方法得到核的巨单极共振的能量逆权重的求和规则 ,从数值上验证了 Dirac海核子态的贡献. A consistent treatment is extremely important in relativistic approaches. We emphasized the consistent approach in relativistic random phase approximation built on relativistic mean filed ground states. The consistent treatment requires that the studies of the ground state and excited states of giant resonances are based on same effective Lagrangian, and on a same complete set of basis. It was found that the effect of the Dirac states could not be neglected, especially in the case of giant...     

Compression modes and the nuclear matter incompressibility coefficient

We review the current status of the nuclear matter (N=Z and no Coulomb interaction) incompressibility coefficient, K _nm , and describe the theoretical and the experimental methods used to determine K _nm from properties of compression modes in nuclei. In particular we consider the long standing problem of the conflicting results obtained for K _nm , deduced from experimental data on excitation cross sections for the isoscalar giant monopole resonance (ISGMR) and data for the isoscalar giant dipole resonance (ISGDR).     

Letter: Generating Static Black Holes in Higher Dimensional Space-Times

In this article we extend to higher dimensional space-times a recent theorem proved by Salgado which characterizes a three-parameter family of static and spherically symmetric solutions to the Einstein Field Equations. As it happens in four dimensions, it is shown that the Schwarzschild, Reissner-Nordström and global monopole solutions in higher dimensions are particular cases from this family.     

Casimir Effect Under Two Dimensional Black Hole Spacetime Background with Global Monopole

A thin layer of the event horizon vicinity to the two-dimension black hole with a global monopole is considered as a system of the Casimir type. The energy-momentum tensor is derived in Boulware vacuum, Hartle-Hawking vacuum and Unruh vacuum respectively. The values are derived in the massless scalar field which satisfies the Dirichlet boundary conditions. Using the Wald's axioms, the result is got which is the same with the one derived by the usual regularized methods. Meanwhile, the energy, energy density, and pressure acting on the boundaries at the asymptotically flat background also are calculated too, and from the energy, Casimir force is derived. The Casimir energy and Casimir force are compared respectively in the background before and after radiation. PACS: 42.50.Lc.