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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.
Analisis Pengaruh Viskositas pada Self-Siphon Nurhayati, Nurhayati; Viridi, Sparisoma; Zen, Freddy Permana
Phi: Jurnal Pendidikan Fisika dan Terapan Vol 4, No 1 (2018)
Publisher : Universitas Islam Negeri Ar-Raniry

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22373/p-jpft.v4i1.7438

Abstract

Penelitian ini bertujuan untuk mengetahui pengaruh nilai viskositas terhadap terjadinya aliran fluida pada self-siphon secara simulasi. Simulasi dilakukan dengan mempertimbangkan gaya-gaya yang bekerja pada single fluid volume element (SFVE). Persamaan gerak pada masingmasing segmen diselesaikan dengan menerapkan hukum Newton. Persamaan-persamaan diselesaikan secara numerik dengan metode Euler. Parameter fisika yang divariasikan dalam simulasi adalah nilai viskositas fluida, karena viskositas mempengaruhi aliran fluida dalam pipa. Berdasarkan penelitian, nilai viskositas fluida η berpengaruh pada dinamika sistem (yang digambarkan oleh kurva terjadinya aliran fluida) namun tidak signifikan pada diameter yang berbeda. Pada nilai viskositas η yang besar, diperlukan panjang pipa yang tercelup dalam fluida (L) yang besar pula. Besarnya panjang pipa L akan memperbesar nilai tekanan hidrostatis sehingga terjadi aliran pada self-siphon.
A cosmological inflation model with inverse minimal and non-minimal coupling between scalar fields and curvature tensors Hikmawan, Getbogi; Zen, Freddy Permana
Indonesian Physics Communication Vol 22, No 2 (2025)
Publisher : Universitas Riau

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31258/jkfi.22.2.111-118

Abstract

This work reviews the cosmological inflation model involving inverted minimal and non-minimal interactions between the scalar field ϕ and its derivatives with the space curvature tensor. The de Sitter exponential expansion and the decaying scalar field conditions are also reviewed to move the model towards the inflationary condition, where as a generator of inflation, the scalar field must decay at the end of time. The scalar and tensor perturbation equations, their respective spectral indices, and the tensor-to-scalar ratio have been calculated to study the nonlinearity of the reviewed model. It is shown that the spectral indices and tensor-to-scalar ratio of the model are in good agreement with the observational data.