相关论文: Massless fields infinitely degenerating with respe…

It is shown that nonlinear terms in equations of gravitons on the background of curved space-time of the expanding Universe can solve the problem of the negative square of the effective mass formally arising in linear approximation for…

The spacetime physics of bulk closed string tachyon condensation is studied at the level of a two-derivative effective action. We derive the unique perturbative tachyon potential consistent with a full class of linearized tachyonic…

In a recent paper we showed that a quintessence scalar field plus a dissipative matter fluid can drive late cosmic accelerated expansion and simultaneously solve the coincidence problem [1]. In this brief report we extend this result to the…

We propose that cosmological magnetic fields generated in regions of finite spatial dimensions may manifest themselves in the global dynamics of the Universe as `dark energy'. We test our model in the context of spatially flat cosmological…

We discuss the dynamics and phenomenology of an oscillating scalar field coupled to the Higgs boson that accounts for the dark matter in the Universe. The model assumes an underlying scale invariance such that the scalar field only acquires…

The evolution of scalar, electromagnetic and gravitational fields around spherically symmetric black hole surrounded by quintessence are studied with special interest on the late-time behavior. In the ring down stage of evolution, we find…

We show that the decay of the D2-\bar{D2} system with large worldvolume magnetic fields can be described in noncommutative gauge theory. Tachyon condensation in this system describes the annihilation of D2-\bar{D2} into $D0$-branes. From…

The idea of the quantum state of the Universe described by some density matrix, i.e mixture of at least two vacua, the trivial symmetric and the nontrivial one with spontaneously broken symmetry is discussed. Nonzero cosmological constant…

Recently, the tachyon cosmology has been represented as dark energy model to support the current acceleration of the universe without phantom crossing. In this paper, we study the dynamics of the tachyon cosmology in which the field plays…

We consider a tachyon field whose Fourier components correspond to spatial momenta with modulus smaller than the mass parameter. The plane wave solutions have them a time evolution which is a real exponential. The field is quantized and the…

It is shown that in the cosmological models based on a vacuum energy decaying as a^{-2}, where a is the scale factor of the universe, the fate of the universe in regard to whether it will collapse in future or expand forever is determined…

We perform a full investigation on dynamics of a new dark energy model in which the four-derivative of a non-canonical scalar field (tachyon) is non-minimally coupled to the vector torsion. Our analysis is done in the framework of…

We propose a physical interpretation of the perturbative breakdown of unitarity in time-like noncommutative field theories in terms of production of tachyonic particles. These particles may be viewed as a remnant of a continuous spectrum of…

We consider the motion of tachyons (faster-than-light particles) in the framework of General Relativity. An important feature is the large contribution of low energy tachyons to the energy-momentum tensor. We also calculate the…

In the present work, it is shown that a chameleon scalar field having a nonminimal coupling with dark matter can give rise to a smooth transition from a decelerated to an accelerated phase of expansion for the universe. It is surprising to…

In this paper, we have considered that the universe is filled with tachyon, hessence (or hantom) dark energies. Subsequently we have investigated the interactions between tachyon and hessence (hantom) dark energies and calculated the…

Generating axion dark matter through the kinetic misalignment mechanism implies the generation of large asymmetries for Standard Model fermions in the early universe. Even if these asymmetries are washed out at later times, they can trigger…

Distance measurements to type Ia supernovae (SNe Ia) indicate that the universe is accelerating and it is spatially flat. Otherwise, the rotation curves for galaxies or galaxy clusters reveal the existence of a dark matter component. Then,…

Within some approaches to loop quantum cosmology, the existence of an Euclidean phase at high density has been suggested. In this article, we try to explain clearly what are the observable consequences of this possible disappearance of…

In this work we study the cosmological evolution of a dark energy model with two scalar fields, i.e. the tachyon and the phantom tachyon. This model enables the equation of state $w$ to change from $w>-1$ to $w<-1$ in the evolution of the…