nan Arianto

Some impacts of Lorentz violation on cosmology

The impact of Lorentz violation on the dynamics of a scalar field is investigated. In particular, we study the dynamics of a scalar field in the scalar-vector-tensor theory where the vector field is constrained to be unity and time like. By taking a generic form of the scalar field action, a generalized dynamical equation for the scalar-vector-tensor theory of gravity is obtained to describe the cosmological solutions. We present a class of exact solutions for an ordinary scalar field or phantom field corresponding to a power law coupling vector and the Hubble parameter. As the results, we find a constant equation of state in de Sitter space-time and power law expansion with the quadratic of coupling vector, while a dynamic equation of state is obtained for n > 2. Then, we consider the inflationary scenario based on the Lorentz violating scalar-vector-tensor theory of gravity with general power-law coupling vector and two typical potentials: inverse power-law and power-law potentials. In fact, both the coupling vector and the potential models affect the dynamics of the inflationary solutions. Finally, we use the dynamical system formalism to study the attractor behavior of a cosmological model containing a scalar field endowed with a quadratic coupling vector and a chaotic potential.

BPS domain walls and vacuum structure of N=1 supergravity coupled to a chiral multiplet

We study BPS domain walls of N=1 supergravity coupled to a chiral multiplet and their Lorentz invariant vacuums which can be viewed as critical points of BPS equations and the scalar potential. Supersymmetry further implies that gradient flows of BPS equations controlled by a holomorphic superpotential and the Kahler geometry are unstable near local maximum of the scalar potential, whereas they are stable around local minimum and saddles of the scalar potential. However, the analysis using renormalization group flows shows that such gradient flows do not always exist particularly in infrared region.

Cosmological evolution of interacting dark energy in Lorentz violation

AbstractThe cosmological evolution of an interacting scalar-field model in which the scalar field interacts with dark matter, radiation, and baryons via Lorentz violation is investigated. We propose a model of interaction through the effective coupling,

Kaluza-Klein brane cosmology with a bulk scalar field

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Attractor Solutions in Lorentz Violating Scalar-Vector-Tensor Theory

. Using dynamical system analysis, we study the linear dynamics of an interacting model and show that the dynamics of critical points are completely controlled by two parameters. Some results can be mentioned as follows. Firstly, the sequence of radiation, the dark matter, and the scalar-field dark energy exist and baryons are subdominant. Secondly, the model also allows for the possibility of having a universe in the phantom phase with constant potential. Thirdly, the effective gravitational constant varies with respect to time through

Some Aspects of Spherical Symmetric Extremal Dyonic Black Holes in 4d N = 1 Supergravity

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Accelerating universe from nonminimal derivative coupling in 5D universal extra dimension

. In particular, we consider the simple case where

Kaluza-Klein two brane worlds cosmology at low energy

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Parameterized Post-Newtonian Expansion of Scalar-Vector-Tensor Theory of Gravity

has a quadratic form and has a good agreement with the modified ΛCDM and quintessence models. Finally, we also calculate the first post-Newtonian parameters for our model.

Dynamics of BPS Domain Walls on Toric Self Dual Einstein Spaces

The brane-world cosmological model in higher-dimensional spacetime with a bulk scalar field is investigated. We derive the