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Indonesian Journal of Physics (IJP)

ijp
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Published by Institut Teknologi Bandung

ISSN : 23018151 EISSN : 29870828 DOI : https://doi.org/10.5614/itb.ijp

Core Subject : Science, Engineering,

Astronomy Computer Science & IT Earth & Planetary Sciences Electrical & Electronics Engineering Energy Engineering

Indonesian Journal of Physics welcomes full research articles in the area of Sciences and Engineering from the following subject areas: Physics, Mathematics, Astronomy, Mechanical Engineering, Civil and Structural Engineering, Chemical Engineering, Electrical Engineering, Geotechnical Engineering, Engineering Science, Environmental Science, Materials Science, and Earth-Surface Processes. Authors are invited to submit articles that have not been published previously and are not under consideration elsewhere.

Arjuna Subject : Fisika dan Astronomi - Fisika Nuklir dan Molekuler, dan Ooptik

Articles 334 Documents

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Effect of Dimensionality on The Electronic Properties of SnSe: A Density Functional Theory Study Fatimah Arofiati Noor; Erik Bhekti Yutomo; Toto Winata
Indonesian Journal of Physics Vol 32 No 2 (2021): Vol 32 No 2 (2021)
Publisher : Institut Teknologi Bandung

This study investigated the structural and electronic properties of bulk, bilayer, and monolayer SnSe using the density functional theory (DFT) method. We succeeded in calculating the bandgap and identifying accurately the transformation of the band structure from bulk to monolayer systems using generalized gradient approximation. An increase in the lattice parameter a and a decrease in the lattice parameter b were observed when the bulk dimensions were reduced to a monolayer. The reduction of van der Waals interactions when the dimensions of a system are reduced is the main factor that causes changes in lattice parameters. The indirect bandgap of bulk SnSe (0.56 eV, 0.3∆→0.7Σ) becomes wider in the monolayer system (0.94 eV, 0.2∆→0.8Σ). Bandgap widening is predicted due to the emergence of the quantum confinement effect in low-dimensional systems. Furthermore, we found the formation of a quasi-degenerate minimum conduction band in the monolayer SnSe. With the formation of these bands, we predict the monolayer SnSe will have better thermoelectric properties than the bulk or bilayer system. This study provides an in-depth understanding of the electronic structure of SnSe and its correlation to thermoelectric properties.

The Effect of Niobium and Rubidium Doping on the Energy Band Gap of a Lithium Tantalate (LiTaO3) Thin Film Agus Ismangil; Fatimah Arofiati Noor; Toto Winata
Indonesian Journal of Physics Vol 32 No 2 (2021): Vol 32 No 2 (2021)
Publisher : Institut Teknologi Bandung

Chemical solution deposition (CSD) is a technique for making a film by keeping synthetic arrangements on the outer layer of the substrate. The outcomes show that the band gap energy of the LiTaO3 film is 1 eV. Electrons are more effectively invigorated to the valence band than to the conduction band on the grounds that the energy required is not excessively huge. Niobium-doped LiTaO3 film has a band gap energy of 1.15 eV. A large amount of energy is needed for electrons to be energized from the valence band to the conduction band. The rubidium-doped LiTaO3 film has a band gap energy of 1.30 eV.

MODIFIED CORRELATION WEIGHT K-NEAREST NEIGHBOR CLASSIFIER USING TRAINING DATASET CLEANING METHOD Efraim Kurniawan Dairo Kette
Indonesian Journal of Physics Vol 32 No 2 (2021): Vol 32 No 2 (2021)
Publisher : Institut Teknologi Bandung

In pattern recognition, the k-Nearest Neighbor (kNN) algorithm is the simplest non-parametric algorithm. Due to its simplicity, the model cases and the quality of the training data itself usually influence kNN algorithm classification performance. Therefore, this article proposes a sparse correlation weight model, combined with the Training Data Set Cleaning (TDC) method by Classification Ability Ranking (CAR) called the CAR classification method based on Coefficient-Weighted kNN (CAR-CWKNN) to improve kNN classifier performance. Correlation weight in Sparse Representation (SR) has been proven can increase classification accuracy. The SR can show the 'neighborhood' structure of the data, which is why it is very suitable for classification based on the Nearest Neighbor. The Classification Ability (CA) function is applied to classify the best training sample data based on rank in the cleaning stage. The Leave One Out (LV1) concept in the CA works by cleaning data that is considered likely to have the wrong classification results from the original training data, thereby reducing the influence of the training sample data quality on the kNN classification performance. The results of experiments with four public UCI data sets related to classification problems show that the CAR-CWKNN method provides better performance in terms of accuracy.

Einstein-Klein-Gordon System in Higher Dimensional Mirda Prisma Wijayanto; Fiki Taufik Akbar Sobar; Bobby Eka Gunara
Indonesian Journal of Physics Vol 32 No 2 (2021): Vol 32 No 2 (2021)
Publisher : Institut Teknologi Bandung

In this present work, we study the Einstein equation coupled with the nonlinear Klein-Gordon equation. We obtain Ricci tensor, scalar curvature, and Einstein equation of the Einstein-Klein-Gordon system in higher dimensional. If we put D=4, our formulations reduce to the four dimensional Einstein-Klein-Gordon system.

Scalar-Torsion Theories in Four Dimensional Static Spacetimes Mulyanto .; Fiki Taufik Akbar; Bobby Eka Gunara
Indonesian Journal of Physics Vol 32 No 2 (2021): Vol 32 No 2 (2021)
Publisher : Institut Teknologi Bandung

In this paper, we consider a class of static spacetimes scalar-torsion theories in four dimensioanal static spacetimes with the scalar potential turned on. We discover that the 2-dimensional submanifold must admit constant triplet structures, one of which is the torsion scalar. This indicates that these equations of motion can be reduced to a single highly non-linear ordinary differential equation known as the master equation. Then, we show that there are no exact solution of the scalar-torsion theory in four dimensions considering the Sinh-Gordon potential.

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

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.

Compatibility of Einstein-Gauss-Bonnet inflation theory with non-minimal derivative coupling in the constant-roll Naufal Aulia Adam; Getbogi Hikmawan; Freddy Permana Zen
Indonesian Journal of Physics Vol 33 No 1 (2022): Vol 33 No 1 (2022)
Publisher : Institut Teknologi Bandung

Inflation is a theory in cosmology that explains that the early universe experienceda very fast expansion in a very short time and is able to explain some cosmological problemsand the presence of gravitational waves generated during the inflation period. Based on theevent GW170817, it was found that c2t = 1, which indicates that the speed of gravitationalwaves is nearly equal to the speed of light. This contradicts several modified theories of gravity,one of which is the Einstein-Gauss-Bonnet theory. This paper examines the compatibility ofEinstein-Gauss-Bonnet inflation theory with the GW170817 phenomenon, with the addition ofthe Non-minimal derivative coupling term and the constant-roll approach and its characteristics.The formulation of observational quantities is carried out using Horndeski theory and EffectiveField Theory with ADM formalism and the calculations are done numerically. The constantvalues are selected in such a way that the spectral index values and tensor-scalar ratios are closeto the 2018 Planck data. The results found that this theory is compatible with GW170817 withthe influence of Gauss-Bonnet term and constant-roll parameter β most dominant.

GW170817 Implementation on Einstein-Gauss-Bonnet Theory with Non Minimal and Non Minimal Derivative Coupling Fitria Khairunnisa; Getbogi Hikmawan; Freddy Permana Zen
Indonesian Journal of Physics Vol 33 No 1 (2022): Vol 33 No 1 (2022)
Publisher : Institut Teknologi Bandung

The GW170817 event manifests that gravitational wave velocity is close to thespeed of light. As a result, several theories of gravity are no longer applicable, including EinsteinGauss-Bonnet (EGB) inflation. However, a constraint equation could be applied so that thetheory could produce a viable result. In this study, the EGB inflation is being extended byadding a non-minimal coupling (NMC) and a non-minimal derivative coupling (NMDC). Freeparameters values were evaluated to obtained viability with observational indices. We use powerlaw and exponential Gauss-Bonnet coupling functions. Each model provides observational valuesof ns and r that are compatible with the observations and has its characteristic. It specifiesthe free parameter that controls the alteration of ns and r values. The power-law model iscontrolled by the power m of the Gauss-Bonnet coupling function and the potential integrationconstant, V2. While the exponential model is controlled by the potential integration constant cand the power m of the exponential function. Some approximations do not hold true so that themodels need to be rectified. Apparently, the rectified power-law model is violating null energycondition (NEC), so we also provide the non-violating NEC power-law model.

Study of Entangled K-meson and Its Decoherence Abas Syahbana; Freddy Permana Zen; Donny Dwiputra
Indonesian Journal of Physics Vol 33 No 1 (2022): Vol 33 No 1 (2022)
Publisher : Institut Teknologi Bandung

In this paper, entangled K-meson model and decoherence phenomenon in thesystem is studied. Using Lindblad equation, dynamical equation of entangled K-meson systemthat interacts with the environment is obtained. We find that non-Hermitian Hamiltonian ofthe system makes completely positive and trace-preserving map (CPT-map) on the space ofdensity matrix does not satisfy trace preserving properties. We also find that purity of densitymatrix can be less than 1=d which does not satisfy the property of purity. From the dynamicalequation, parameters related to the decoherence of the system, decoherence parameter (λ) andeffective decoherence parameter (ζ), are determined. Using Standard Least-Squares method,we obtain ζ = 0; 13±0; 865. This result is in accordance with references result that use effectivevariance method, ζ = 0; 13±+0 -0;;16 15. We show that ζ = 0; 13±+0 -0;;16 15 corresponds with referencesresult, λ = (1; 84±+2 -2;;50 17) × 10-12 MeV. The value of both parameters are close to zero relativeto ζ = 1 or λ ! 1. It means that the interaction between system and environment doesnot affect the system significantly. Therefore, quantum properties in the system related to theentanglement of the strangeness is preserved.

Blow-up Dynamics of Higher Dimensional Klein-Gordon Equation with Nonminimal Coupling in Subcritical Case Mirda Prisma Wijayanto; Fiki Taufik Akbar; Bobby Eka Gunara
Indonesian Journal of Physics Vol 33 No 1 (2022): Vol 33 No 1 (2022)
Publisher : Institut Teknologi Bandung

The aim of this present work is to study the blow-up dynamics and lifespanestimate for solution to higher dimensional Klein-Gordon Equation in subcritical case, in which1 < p < psc. We construct the equation of motion from the Lagrangian of Klein-Gordon withnon-minimal coupling, where the coupling interaction of the scalar field is proportional to thescalar curvature of the spacetime. The equation of motion has the form like nonlinear dampedwave equation with mass. The novelty of this work is the time dependent of nonlinear term. Weuse test function method to proof the lifespan estimate.

Page 30 of 34 | Total Record : 334

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Asril Pramutadi Andi Mustari

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IJPhysicsITB@gmail.com

Phone
+6222-2500834

Journal Mail Official
ijp-journal@itb.ac.id

Editorial Address
Prodi Sarjana dan Pascasarjana Fisika Fakultas Matematika dan Ilmu Pengetahuan Alam Institut Teknologi Bandung Gedung Fisika, Jalan Ganesa 10, Bandung 40132, INDONESIA

Location
Kota bandung,

Jawa barat

INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Home Page

OAI Link

Editorial Team

Contact

Reviewer

Google Scholar

Contact Name Asril Pramutadi Andi Mustari

Contact Email IJPhysicsITB@gmail.com

Phone +6222-2500834

Journal Mail Official ijp-journal@itb.ac.id

Editorial Address Prodi Sarjana dan Pascasarjana Fisika Fakultas Matematika dan Ilmu Pengetahuan Alam Institut Teknologi Bandung Gedung Fisika, Jalan Ganesa 10, Bandung 40132, INDONESIA

Location Kota bandung, Jawa barat INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Contact Name
Asril Pramutadi Andi Mustari

Contact Email
IJPhysicsITB@gmail.com

Phone
+6222-2500834

Journal Mail Official
ijp-journal@itb.ac.id

Editorial Address
Prodi Sarjana dan Pascasarjana Fisika Fakultas Matematika dan Ilmu Pengetahuan Alam Institut Teknologi Bandung Gedung Fisika, Jalan Ganesa 10, Bandung 40132, INDONESIA

Location
Kota bandung,

Jawa barat

INDONESIA