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1.
The spacetime metric of a spinning cosmic string may be formally represented in flat spacetime by a nonhomogeneous bianisotropic medium. The constitutive parameters of this bianisotropic medium can be established using a noncovariant formalism, thereby paving the way for laboratory simulations of a spinning cosmic string using metamaterial technology. 相似文献
2.
K. Bakke 《General Relativity and Gravitation》2013,45(10):1847-1859
In this contribution, we study the Dirac oscillator under the influence of noninertial effects of a rotating frame in the cosmic string spacetime. We show that both noninertial effects and the topology of the cosmic string spacetime restrict the physical region of the spacetime where the quantum particle can be placed, and discuss two different cases of bound states solutions of the Dirac equation by analysing the behaviour of the Dirac oscillator frequency. 相似文献
3.
《Physics letters. [Part B]》2006,632(2-3):151-154
We calculate the corrections to the fine structure constant in the spacetime of a cosmic string. These corrections stem from the generalized uncertainty principle. In the absence of a cosmic string our result here is in agreement with our previous result. 相似文献
4.
Josevi de S. Carvalho E. Passos Claudio Furtado Fernando Moraes 《The European Physical Journal C - Particles and Fields》2008,57(4):817-822
The relativistic quantum dynamics of a spinorial quantum particle in the presence of a chiral conical background is investigated.
We study the gravitational Berry geometric quantum phase acquired by a spin 1/2 particle in the chiral cosmic string spacetime.
We obtain the result that this phase depends on the global features of this spacetime. We also consider the case that a string
possesses an internal magnetic flux and obtain the geometric quantum phase in this case. The spacetime of multiple chiral
cosmic strings is considered and the relativistic Berry quantum phase is also obtained. 相似文献
5.
In this paper, we study the influence of the Aharonov–Casher effect [Y. Aharonov, A. Casher, Phys. Rev. Lett. 53 (1984) 319] on the Dirac oscillator in three different scenarios of general relativity: the Minkowski spacetime, the cosmic string spacetime and the cosmic dislocation spacetime. In this way, we solve the Dirac equation and obtain the energy levels for bound states and the Dirac spinors for positive-energy solutions. We show that the relativistic energy levels depend on the Aharonov–Casher geometric phase. We also discuss the influence of curvature and torsion on the relativistic energy levels and the Dirac spinors due to the topology of the cosmic string and cosmic dislocation spacetimes. 相似文献
6.
Knut Bakke 《Brazilian Journal of Physics》2012,42(5-6):437-444
We discuss the behavior of external fields interacting with a Dirac neutral particle with a permanent electric dipole moment in order to achieve relativistic bound state solutions in a noninertial frame and in the presence of a topological defect spacetime. We show that the noninertial effects of the Fermi?CWalker reference frame induce a radial magnetic field even in the absence of magnetic charges, which is influenced by the topology of the cosmic string spacetime. We then discuss the conditions that the induced fields must satisfy to yield the relativistic bound states corresponding to the Landau?CHe?CMcKellar?CWilkens quantization in the cosmic string spacetime. Finally, we obtain the Dirac spinors for positive-energy solutions and the Gordon decomposition of the Dirac probability current. 相似文献
7.
L. C. N. Santos C. C. BarrosJr. 《The European Physical Journal C - Particles and Fields》2017,77(3):186
In this paper we present two different classes of solutions for the Klein–Gordon equation in the presence of a scalar potential under the influence of noninertial effects in the cosmic string spacetime. We show that noninertial effects restrict the physical region of the spacetime where the particle can be placed, and furthermore that the energy levels are shifted by these effects. In addition, we show that the presence of a Coulomb-like scalar potential allows the formation of bound states when the Klein–Gordon equation is considered in this kind of spacetime. 相似文献
8.
In this Letter the equation of circular loops of cosmic string with periodic tension is investigated in the Minkowski spacetime and Robertson–Walker universe respectively. We find that the cosmic string loops possessing this kind of time-varying tension will evolve to oscillate instead of collapsing to form a black hole if their initial radii are not small enough. 相似文献
9.
Mainuddin Ahmed Elias Uddin Biswas 《International Journal of Theoretical Physics》1996,35(12):2625-2630
We study the equilibrium configurations of a cosmic string described by the Nambu action in curved spacetime such as the Kerr-Newman-Kasuya spacetime, which is the Kerr-Newman spacetime involved with extra magnetic monopole charge. In this study it is interesting to note that the physical results remain the same whether or not the magnetic monopole does exist in nature. 相似文献
10.
From the modified Maxwell theory coupled to gravity, we establish a possible scenario of the violation of the Lorentz symmetry and write an effective metric for the cosmic string spacetime. Then, we investigate the arising of an analogue of the Anandan quantum phase for a relativistic Dirac neutral particle with a permanent magnetic dipole moment in the cosmic string spacetime under Lorentz symmetry breaking effects. Besides, we analyse the influence of the effects of the Lorentz symmetry violation and the topology of the defect on the Aharonov–Casher geometric quantum phase in the nonrelativistic limit. 相似文献
11.
We study the equilibrium configurations of a cosmic string described by the Nambu action in the NUT-Kerr-Newman spacetime which includes as special cases the Kerr-Newman black hole spacetime as well as the NUT spacetime which is considered as a cosmological model. In this study it is interesting to note that one can obtain parallel results for the Kerr-Newman black hole as well as the NUT spacetime. 相似文献
12.
A study of ray trajectories was undertaken for the Tamm medium which represents the spacetime of a zero-tension cosmic spinning string, under the geometric-optics approximation. Our numerical studies revealed that: (i) rays never cross the string's boundary; (ii) the Tamm medium supports evanescent waves in regions of phase space that correspond to those regions of the string's spacetime which could support closed timelike curves; and (iii) a spinning string can be slightly visible while a non-spinning string is almost perfectly invisible. 相似文献
13.
《Nuclear Physics B》1986,278(3):550-576
We construct string theory versions of cosmic strings by considering orbifold compactifications of spacetime down to two dimensions. 相似文献
14.
We calculate the electrostatic self-force on an electric dipole in the spacetime generated by a static, thin, infinite and straight cosmic string. The electric dipole is held fixed in different configurations, namely, parallel, perpendicular to the cosmic string and oriented along the azimuthal direction around this topological defect, which is stretched along the z axis. We show that the self-force is equivalent to an interaction of the electric dipole with an effective dipole moment which depends on the linear mass density of the cosmic string and on the configuration. The plots of the self-forces as functions of the parameter which determines the angular deficit of the cosmic string are shown for those different configurations. 相似文献
15.
WANG Jun WANG Yong-Jiu 《理论物理通讯》2006,46(12)
In this paper the generalized equations for spinning space are investigated and the constants of motion are derived in terms of the solutions of these equations. We study the geodesic motion of the pseudo-classical spinning particles in the spacetime produced by an idealized cosmic string and the non-extreme stationary axisymmetric black hole spacetime. The bound state orbits in a plane are discussed. We also show, for a conical spacetime and the Kerr spacetime, that the geodesic motion of spinning particles is different. 相似文献
16.
WANG Jun WANG Yong-Jiu 《理论物理通讯》2006,46(6):995-1000
In this paper the generalized equations for spinning space are investigated and the constants of motion are derived in terms of the solutions of these equations. We study the geodesic motion of the pseudo-classical spinning particles in the spacetime produced by an idealized cosmic string and the non-extreme stationary axisymmetric black hole spacetime. The bound state orbits in a plane are discussed. We also show, for a conical spacetime and the Kerr spacetime, that the geodesic motion of spinning particles is different. 相似文献
17.
In this work the equation of circular loops of cosmic string possessing time-dependent tension is studied in the de Sitter
spacetime. We find that the cosmic string loops with initial radius r(t
0)>0.707L, L de Sitter radius, should not collapse to form a black hole. It is also found that in the case of r(t
0)<0.707L a loop of cosmic string whose tension depends on some power of cosmic time can not become a black hole if the power is lower
than a critical value which is associated with the initial size of the loop. Our research gives rise to some important corrections
to the conclusion in the case of loops of cosmic string with constant tension in the same background. 相似文献
18.
We investigate noninertial effects on the scattering problem of a nonrelativistic particle in the cosmic string spacetime. By considering the nonrelativistic limit of the Dirac equation we are able to show, in the regime of small rotational frequencies, that the phase shift has two contribution: one related to the noninertial reference frame, and the other, due to the cosmic string conical topology. We also show that both the incident wave and the scattering amplitude are altered as a consequence of the noninertial reference frame and depend on the rotational frequency. 相似文献
19.
We present the spacetime interval of thenonradiated cosmic string oscillating as standing waves.The influence of string oscillations on the dynamics ofa probe cosmic thread that performs free oscillations and moves in its vicinity, isdiscussed. 相似文献
20.
Peter Nwabuzor Collins Edet Akpan Ndem Ikot Uduakobong Okorie Morris Ramantswana Ridha Horchani Abdel-Haleem Abdel-Aty Gaotsiwe Rampho 《Entropy (Basel, Switzerland)》2021,23(8)
In this study, the impacts of TD on the energy spectra and thermal properties of LiH, TiC and I2 diatomic molecules is considered. The Schrodinger equation in cosmic string spacetime is solved with the generalized Morse potential using the well-known (NU) method. The energy spectra and eigenfunction are obtained respectively. The energy spectra is used to obtain the partition function which is then used to evaluate the thermal properties of the system is evaluated accordingly. We find that the energy spectra in the presence of the TD differ from their flat Minkowski spacetime analogue. The effects of the deformation parameter and TD on the thermal properties of the system is also analysed in detail. We observe that the specific heat capacity of the system tends to exhibit quasi-saturation as the deformation parameter and topological defect approaches unity. The results of our study can be applied in the astrophysical situation where these modifications exist in the understanding of spectroscopical data and it may be used as a probe of the presence of a cosmic string or a global monopole in the Universe. 相似文献