Sutiono, Azwar
Lab Fisika Teori, THEPI, Program Studi Fisika, Fakultas Matematika Dan Ilmu Pengetahuan Alam, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132, Indonesia

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Persamaan Gelombang Gravitasi untuk Teori Proca yang Digeneralisasi Marliana Marliana; Agustina Widiyani; Azwar Sutiono; Agus Suroso; Freddy P. Zen
Prosiding SNFA (Seminar Nasional Fisika dan Aplikasinya) 2020: Prosiding SNFA (Seminar Nasional Fisika dan Aplikasinya) 2020
Publisher : Universitas Sebelas Maret

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/prosidingsnfa.v5i0.46604

Abstract

Abstract: The direct detection of gravitational waves from binary black holes and neutron stars have been taking a new oportunities to test teori of gravity.The gravitational wave is affected by the modification of a gravity theory during propagation at cosmological distances. By comparing general equation of gravtiational wave and modification of gravity theory, is obtained equation of gravitational wave for the generalized Proca theories. As a result, we find equation of gravitational wave for the generalized Proca theory. We conclude that the massive vector field affected propagation of gravitational wave.  we can use the result to test the generalized Proca theory.    Abstrak: Dengan terdeteksinya gelombang gravitasi secara langsung dari biner lubang hitam dan bintang neutron menjadi kesempatan untuk dapat menguji teori gravitasi yang sedang dikembangkan.Gelombang gravitasi secara umum dipengaruhi oleh modifikasi teori gravitasi selama penjalarannya pada jarak kosmologi. Dengan membandingkan persamaan gelombang gravitasi dengan teori modifikasi yang dikembangkan, diperoleh persamaan umum gelombang gravitasi dari teori gravitasi yang dikembangkan. Pada artikel ini diperoleh persamaan gelombang gravitasi untuk teori Proca yang digeneralisasi. Dapat disimpulkan bahwa fungsi yang mengandung vektor medan masif dapat mempengaruhi gelombang gravitasi. Persamaan ini dapat digunakan untuk menguji teori Proca yang digeneralisasi.
Thin-shell Solution of Chameleon Mechanism in Brans-Dicke Scalar-Tensor Model Azwar Sutiono; Agustina Widiyani; Marliana Marliana; Getbogi Hikmawan; Agus Suroso; Freddy Permana Zen
Indonesian Journal of Physics Vol 33 No 1 (2022): Vol 33 No 1 (2022)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (277.95 KB) | DOI: 10.5614/itb.ijp.2022.33.1.1

Abstract

We investigated the chameleon screening mechanism in Brans-Dicke scalar-tensor theory. We preserved the fundamental premise of the typical chameleon mechanism, which is that the field is huge in high-density environments but essentially free in low-density environments like the solar system. We discovered thin-shell solutions for a static and spherical symmetric body and demonstrated the model’s applicability to local data.
Gravitational Wave Propagation for The Generalized Proca Theories marliana lutan; Agustina Widiyani; Azwar Sutiono; Getbogi Hikmawan; Agus Suroso; Freddy Permana Zen
Indonesian Journal of Physics Vol 33 No 1 (2022): Vol 33 No 1 (2022)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (177.093 KB) | DOI: 10.5614/itb.ijp.2022.33.1.7

Abstract

In general relativity, a gravitational wave propagates with the speed of light, but inthe alternative theories of gravity, propagation speed could deviate from the speed of lightdue to the modification of gravity. Gravitational waves are influenced by modified gravityduring propagation at the cosmological distance. In this paper, we investigate thepropagation of a gravitational wave of the generalized Proca theories by consideringgravitational wave as the gravitational field propagates in spacetime as a wave perturbing flatspacetime. We show that the arbitrary functions G3, G4, and G5 can be the sources ofdeviation of the speed of the gravitational wave.
An Interacting Dark Energy Model with Nonminimal Derivative Coupling in the Parameterized Post-Friedmannian Framework Agustina Widiyani; Azwar Sutiono
Indonesian Journal of Physics Vol 33 No 2 (2022): Vol 33 No 2 (2022)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (312.321 KB) | DOI: 10.5614/itb.ijp.2022.33.2.1

Abstract

We investigation the parameterization of the cosmological model with the nonminimal derivative coupling of a scalar field where gravity is coupled nonminimally with the derivatives of dark energy components in the form of a scalar field. We follow the parameterized post-Friedmannian approach for the interacting dark energy theories. We show how the big number of free functions can be reduced by limiting certain assumptions to a few non-zero coefficients. We only consider the case that the dark sector contains at most second order in time derivatives of the metric and scalar fields. In this paper, we demonstrate their use through an example of the dark sector interactions model and classify them according to the current literature.