Combining the general relativity and the uncertainty relation in quantum mechanics, the energy density of quantum fluctuations of space-time can be viewed as dark energy. The so-called agegraphic dark energy model is ...Combining the general relativity and the uncertainty relation in quantum mechanics, the energy density of quantum fluctuations of space-time can be viewed as dark energy. The so-called agegraphic dark energy model is just based on this viewpoint, in which the age of the universe is introduced as the length measure. Recently, the new agegraphic dark energy model was proposed, where the dynamical dark energy is measured by the conformal age of the universe. On the other hand, scalar-field dark energy models like tachyons are often regarded as an effective description of some underlying theory of dark energy. In this paper, we show that the new agegraphic dark energy can be described completely by a tachyon scalar-field. We thus reconstruct the potential and the dynamics of the tachyon scalar-field, according to the evolution of the new agegraphic dark energy.展开更多
Schrödinger equation for pair of two massless Dirac particles when magnetic field is applied in Landau gauge is solved exactly. In this case, the separation of center of mass and relative motion is obtained. L...Schrödinger equation for pair of two massless Dirac particles when magnetic field is applied in Landau gauge is solved exactly. In this case, the separation of center of mass and relative motion is obtained. Landau quantization ε = ±B/?l for pair of two Majorana fermions coupled via a Coulomb potential from massless chiral Dirac equation in cylindric coordinate is found. The root ambiguity in energy spectrum leads into Landau quantization for bielectron, when the states in which the one simultaneously exists are allowed. The tachyon solution with imaginary energy in Cooper problem (ε 2 < 0) is found. The continuum symmetry of Dirac equation allows perfect pairing between electron Fermi spheres when magnetic field is applied in Landau gauge creating a Cooper pair.展开更多
Production of tachyons in, among other things, air showers would be in accordance with predictions of general relativity. Some such tachyons would travel with a precisely determined speed, almost equal to 5c/3 relativ...Production of tachyons in, among other things, air showers would be in accordance with predictions of general relativity. Some such tachyons would travel with a precisely determined speed, almost equal to 5c/3 relative to the earth, and would be registered high above the region of creation of air showers, e.g. on board of a satellite. A very simple experiment designed to detect these tachyons is outlined here. Brief justification to search for tachyons is also given.展开更多
In this work the concept of generally covariant duality is treated with the introduction of generalized Levi-Civita tensor within the framework of vierbein formalism. The equations for the attached Lorentz scalar fiel...In this work the concept of generally covariant duality is treated with the introduction of generalized Levi-Civita tensor within the framework of vierbein formalism. The equations for the attached Lorentz scalar fields are derived from vierbein postulate. It is shown that the masses of the associated particles including that with negative square mass are completely determined by Einstein’s cosmological constant.展开更多
We have studied the tachyon intermediate and logamediate warm inflation in loop quantum cosmological background by taking the dissipative co-efficient Γ = Γ_0(where Γ_0 is a constant) in "intermediate" in...We have studied the tachyon intermediate and logamediate warm inflation in loop quantum cosmological background by taking the dissipative co-efficient Γ = Γ_0(where Γ_0 is a constant) in "intermediate" inflation and Γ = V(φ),(where V(φ) is the potential of tachyonic field) in "logamediate" inflation. We have assumed slow-roll condition to construct scalar field φ, potential V, N-folds, etc. Various slow-roll parameters have also been obtained.We have analyzed the stability of this model through graphical representations.展开更多
We investigate the structure of solutions of boundary value problems for a non-linear pseudodifferential equation describing the dynamics(rolling)of p-adic closed strings for a scalar tachyon field.
In this study,the scenario of a two-component warm tachyon inflation is considered,where the tachyon field plays the role of the inflaton by driving the inflation.During inflation,the tachyon scalar field interacts wi...In this study,the scenario of a two-component warm tachyon inflation is considered,where the tachyon field plays the role of the inflaton by driving the inflation.During inflation,the tachyon scalar field interacts with the other component of the Universe,which is assumed to be photon gas,i.e.,radiation.The interacting term contains a dissipation coefficient,and the study is modeled based on two different and familiar choices of the coefficient that were studied in the literature.By employing the latest observational data,the acceptable ranges for the free parameters of the model are obtained.For any choice within the estimated ranges,there is an acceptable concordance between the theoretical predictions and observations.Although the model is established based on several assumptions,it is crucial to verify their validity for the obtained values of the free parameters of the model.It is found that the model is not self-consistent for all values of the ranges,and for some cases,the assumptions are violated.Therefore,to achieve both self-consistency and agreement with the data,the parameters of the model must be constrained.Subsequently,we consider the recently proposed swampland conjecture,which imposes two conditions on the inflationary models.These criteria rule out some inflationary models;however,warm inflation is among those that successfully satisfy the swampland criteria.We conduct a precise investigation,which indicates that the proposed warm tachyon inflation cannot satisfy the swampland criteria for some cases.In fact,for the first case of the dissipation coefficient,in which,there is dependency only on the scalar field,the model agrees with observational data.However,it is in direct tension with the swampland criteria.Nevertheless,for the second case,wherein the dissipation coefficient has a dependency on both the scalar field and temperature,the model exhibits acceptable agreement with observational data,and suitably satisfies the swampland criteria.展开更多
We consider a tachyonic model of dark energy in which scalar field non-minimally coupled with curvature and kinetic part of its Lagrangian density.Additionally the model contains the Gauss–Bonnet coupling to the scal...We consider a tachyonic model of dark energy in which scalar field non-minimally coupled with curvature and kinetic part of its Lagrangian density.Additionally the model contains the Gauss–Bonnet coupling to the scalar field through an arbitrary function.The non-minimal Gauss–Bonnet coupling function and scalar field potential have been obtained for power-law solution and then for a dynamically varying equation of state.We have extracted the required condition for the so-called phantom divide line crossing in the model and represented such a crossing numerically.展开更多
This paper deals with some aspects of two-time physics (i.e., 2T + 3S five-dimensional space) for a Minkowski-like space with distinct speeds of causality for the time dimensions. Detailed calculations are provided to...This paper deals with some aspects of two-time physics (i.e., 2T + 3S five-dimensional space) for a Minkowski-like space with distinct speeds of causality for the time dimensions. Detailed calculations are provided to obtain results of Kaluza-Klein type compactification for free massive scalar fields and abelian free gauge fields. As already indicated in the literature, a tower of massive fields results from the compactification with mass terms having signs opposite to those of the ones appearing in other five-dimensional theories with an extra space dimension. We perform elaborate numerical calculations to highlight the magnitude of the imaginary masses and ask if we need to explore alternative compactification techniques.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 10705041)
文摘Combining the general relativity and the uncertainty relation in quantum mechanics, the energy density of quantum fluctuations of space-time can be viewed as dark energy. The so-called agegraphic dark energy model is just based on this viewpoint, in which the age of the universe is introduced as the length measure. Recently, the new agegraphic dark energy model was proposed, where the dynamical dark energy is measured by the conformal age of the universe. On the other hand, scalar-field dark energy models like tachyons are often regarded as an effective description of some underlying theory of dark energy. In this paper, we show that the new agegraphic dark energy can be described completely by a tachyon scalar-field. We thus reconstruct the potential and the dynamics of the tachyon scalar-field, according to the evolution of the new agegraphic dark energy.
文摘Schrödinger equation for pair of two massless Dirac particles when magnetic field is applied in Landau gauge is solved exactly. In this case, the separation of center of mass and relative motion is obtained. Landau quantization ε = ±B/?l for pair of two Majorana fermions coupled via a Coulomb potential from massless chiral Dirac equation in cylindric coordinate is found. The root ambiguity in energy spectrum leads into Landau quantization for bielectron, when the states in which the one simultaneously exists are allowed. The tachyon solution with imaginary energy in Cooper problem (ε 2 < 0) is found. The continuum symmetry of Dirac equation allows perfect pairing between electron Fermi spheres when magnetic field is applied in Landau gauge creating a Cooper pair.
文摘Production of tachyons in, among other things, air showers would be in accordance with predictions of general relativity. Some such tachyons would travel with a precisely determined speed, almost equal to 5c/3 relative to the earth, and would be registered high above the region of creation of air showers, e.g. on board of a satellite. A very simple experiment designed to detect these tachyons is outlined here. Brief justification to search for tachyons is also given.
文摘In this work the concept of generally covariant duality is treated with the introduction of generalized Levi-Civita tensor within the framework of vierbein formalism. The equations for the attached Lorentz scalar fields are derived from vierbein postulate. It is shown that the masses of the associated particles including that with negative square mass are completely determined by Einstein’s cosmological constant.
文摘新一代Tachyon光纤通道控制器HPFC-6600 QE4为四通道4Gbit／s光纤通道控制器，带有PCI-Express总线，可以与PMC-Sierra的4 Gbit／s光纤通道回路交换器件进行无缝连接，为企业级存储系统提供完整的光纤到磁盘的解决方案。另外QE4还可与PMC-Sierra的3G Max SAS扩展器及SAS／SATA多路复用器一起使用，以构建成本优化的层叠存储系统架构。
文摘We have studied the tachyon intermediate and logamediate warm inflation in loop quantum cosmological background by taking the dissipative co-efficient Γ = Γ_0(where Γ_0 is a constant) in "intermediate" inflation and Γ = V(φ),(where V(φ) is the potential of tachyonic field) in "logamediate" inflation. We have assumed slow-roll condition to construct scalar field φ, potential V, N-folds, etc. Various slow-roll parameters have also been obtained.We have analyzed the stability of this model through graphical representations.
基金The work was partially supported by grant of the President RF(No.NSh-1542.2003.1)
文摘We investigate the structure of solutions of boundary value problems for a non-linear pseudodifferential equation describing the dynamics(rolling)of p-adic closed strings for a scalar tachyon field.
基金The work of A.M.has been supported financially by‘Vice Chancellorship of Research and Technology,University of Kurdistan’under research Project No.98/10/34704The work of T.G.has been supported financially by‘Vice Chancellorship of Research and Technology,University of Kurdistan’under research Project No.98/11/2724。
文摘In this study,the scenario of a two-component warm tachyon inflation is considered,where the tachyon field plays the role of the inflaton by driving the inflation.During inflation,the tachyon scalar field interacts with the other component of the Universe,which is assumed to be photon gas,i.e.,radiation.The interacting term contains a dissipation coefficient,and the study is modeled based on two different and familiar choices of the coefficient that were studied in the literature.By employing the latest observational data,the acceptable ranges for the free parameters of the model are obtained.For any choice within the estimated ranges,there is an acceptable concordance between the theoretical predictions and observations.Although the model is established based on several assumptions,it is crucial to verify their validity for the obtained values of the free parameters of the model.It is found that the model is not self-consistent for all values of the ranges,and for some cases,the assumptions are violated.Therefore,to achieve both self-consistency and agreement with the data,the parameters of the model must be constrained.Subsequently,we consider the recently proposed swampland conjecture,which imposes two conditions on the inflationary models.These criteria rule out some inflationary models;however,warm inflation is among those that successfully satisfy the swampland criteria.We conduct a precise investigation,which indicates that the proposed warm tachyon inflation cannot satisfy the swampland criteria for some cases.In fact,for the first case of the dissipation coefficient,in which,there is dependency only on the scalar field,the model agrees with observational data.However,it is in direct tension with the swampland criteria.Nevertheless,for the second case,wherein the dissipation coefficient has a dependency on both the scalar field and temperature,the model exhibits acceptable agreement with observational data,and suitably satisfies the swampland criteria.
文摘We consider a tachyonic model of dark energy in which scalar field non-minimally coupled with curvature and kinetic part of its Lagrangian density.Additionally the model contains the Gauss–Bonnet coupling to the scalar field through an arbitrary function.The non-minimal Gauss–Bonnet coupling function and scalar field potential have been obtained for power-law solution and then for a dynamically varying equation of state.We have extracted the required condition for the so-called phantom divide line crossing in the model and represented such a crossing numerically.
文摘This paper deals with some aspects of two-time physics (i.e., 2T + 3S five-dimensional space) for a Minkowski-like space with distinct speeds of causality for the time dimensions. Detailed calculations are provided to obtain results of Kaluza-Klein type compactification for free massive scalar fields and abelian free gauge fields. As already indicated in the literature, a tower of massive fields results from the compactification with mass terms having signs opposite to those of the ones appearing in other five-dimensional theories with an extra space dimension. We perform elaborate numerical calculations to highlight the magnitude of the imaginary masses and ask if we need to explore alternative compactification techniques.
