Self-duality equations for spherically symmetric SU(2) gauge fields

A model of spherically symmetric SU(2) gauge theory is considered. The self-duality equations are written and it is shown that they are compatible with the Einstein-Yang-Mills equations. It is proven that this property is true for any gauge theory with curved base space-time and having a compact Lie group as structural group.Comment: 8 page

Solutions without singularities in gauge theory of gravitation

A de-Sitter gauge theory of the gravitational field is developed using a spherical symmetric Minkowski space-time as base manifold. The gravitational field is described by gauge potentials and the mathematical structure of the underlying space-time is not affected by physical events. The field equations are written and their solutions without singularities are obtained by imposing some constraints on the invariants of the model. An example of such a solution is given and its dependence on the cosmological constant is studied. A comparison with results obtained in General Relativity theory is also presented. Keywords: gauge theory, gravitation, singularity, computer algebraComment: 9 pages, no figure

On Black Holes and Cosmological Constant in Noncommutative Gauge Theory of Gravity

Deformed Reissner-Nordstr\"om, as well as Reissner-Nordstr\"om de Sitter, solutions are obtained in a noncommutative gauge theory of gravitation. The gauge potentials (tetrad fields) and the components of deformed metric are calculated to second order in the noncommutativity parameter. The solutions reduce to the deformed Schwarzschild ones when the electric charge of the gravitational source and the cosmological constant vanish. Corrections to the thermodynamical quantities of the corresponding black holes and to the radii of different horizons have been determined. All the independent invariants, such as the Ricci scalar and the so-called Kretschmann scalar, have the same singularity structure as the ones of the usual undeformed case and no smearing of singularities occurs. The possibility of such a smearing is discussed. In the noncommutative case we have a local disturbance of the geometry around the source, although asymptotically at large distances it becomes flat.Comment: Based on a talk given at the International Conference on Fundamental and Applied Research in Physics "Farphys 2007", 25-28 October 2007, Iasi, Romani

Noncommutative gauge theory using covariant star product defined between Lie-valued differential forms

We develop an internal gauge theory using a covariant star product. The space-time is a symplectic manifold endowed only with torsion but no curvature. It is shown that, in order to assure the restrictions imposed by the associativity property of the star product, the torsion of the space-time has to be covariant constant. An illustrative example is given and it is concluded that in this case the conditions necessary to define a covariant star product on a symplectic manifold completely determine its connection.Comment: AMS-LaTeX 19 pages. v2: corrections in language and equations (typos), expanded sections 3-5, added references. v3: minor presentational and grammatical corrections, completed, corrected and reordered some references

Covariant star product on symplectic and Poisson spacetime manifolds

A covariant Poisson bracket and an associated covariant star product in the sense of deformation quantization are defined on the algebra of tensor-valued differential forms on a symplectic manifold, as a generalization of similar structures that were recently defined on the algebra of (scalar-valued) differential forms. A covariant star product of arbitrary smooth tensor fields is obtained as a special case. Finally, we study covariant star products on a more general Poisson manifold with a linear connection, first for smooth functions and then for smooth tensor fields of any type. Some observations on possible applications of the covariant star products to gravity and gauge theory are made.Comment: AMS-LaTeX, 27 pages. v2: minor corrections in presentation and language, added one referenc

Mikrozonasi Seismic dan Analisis Respon Site Spec Ific Kota Palu

Beberapa peneliti telah melakukan penelitian dan membuat Peta Gempa Indonesia denganversi masing – masing, penelitian ini menyajikan penelitian untuk mendapatkan Peak GroundAcceleration (PGA) untuk beberapa tempat di Kota Palu berdasarkan metoda yang lebihlengkap, sistematis dan berusaha mengurangi faktor ketidak pastian dalam setiap langkahperhitungan yang dilakukan.Penelitian ini akan meliputi pengumpulan dan pengolahan data gempa, studi seismotektonikdan analisis resiko gempa. Data-data gempa dikumpulkan dari tahun 1904 – 2006. Data gempakemudian diolah sehingga didapat data gempa utama dan kelengkapannya.Untukmemperhitungkan faktor ketidak pastian dari masing - masing tahapan perhitungan dipakaimetoda logic tree.Analisis dilakukan dengan bantuan program Equevalent Linear Earthquake Respons Analysis(EERA). Properties dinamik tanah dievaluasi dari data-data hasil penyelidikan tanah yangdikumpulkan dibeberapa tempat di Kota Palu. Hasil dari analisis respon site denganmenggunakan program EERA, dapat digunakan sebagai data masukan untuk pembuatanrespon spectr

PENGARUH MODEL PEMBELAJARAN DIRECT LEARNING TERHADAP HASIL BELAJAR SISWA PADA MATA PELAJARAN PEMOGRAMAN DASAR MENGGUNAKAN APLIKASI DEV- C++ KELAS X TKJ SMKN 6 KUPANG

Penelitian ini bertujuan untuk mengetahui 1) adanya pengaruh penggunaanmodel pembelajaran direct learning terhadap hasil belajar siswa mata pelajaranpemograman dasar kelas X TKJ 1 SMK Negeri 6 Kupang. 2) bagaimana pengaruhpenggunaan model pembelajaran direct learning terhadap hasil belajar siswa matapelajaran pemograman dasar kelas X TKJ 1 SMK Negeri 6 Kupang. Metodepenelitian yang digunakan dalam penelitian ini yaitu penelitian eksperimen, desainperancangan penelitian yang digunakan yaitu Pre-experimental Design, penelitian inimemiliki satu kelompok sebagai subjek penelitian yaitu kelas experimen. Jenispenelitian yang digunakan adalah One Group Pretest-Posttest Design. Pengumpulandata yang dilakukan melalui tes awal, tes akhir dan pengamatan. Analisis data yangdigunakan adalah uji persyaratan analisis dengan uji homogenitas serta uji hipotesisdengan analisis uji regeresi sederhana dan uji t korelasi dengan bantuan StatisticalProduct and Service Solution (SPSS). Hasil penelitian menunjukkan bahwa modelpembelajaran direct learning terhadap hasil belajar dilihat dari nilai Y= 52,875 +0,571X P value < ꭤ sebesar (0,000<0,05), maka disimpulkan bahwa ada pengaruhantara model pembelajaran direct learning dengan hasil belajar siswa. Untukmengetahui bagaimana pengaruh model pembelajaran direct learning terhadap hasilbelajar diperoleh thitung =6,156 didapatkan nilai ttabel 2,032 dengan df = 34. Jadi Nilaithitung > ttabel (6,156>2,032) dan nilai Rsquer = 0,527 maka dapat disimpulkan bahwaterdapat pengaruh yang signifikan sebesar 52,7% antara model pembelajaran directlearning terhadap hasil belajar siswa

Gauge field theories with covariant star-product

A noncommutative gauge theory is developed using a covariant star-product between differential forms defined on a symplectic manifold, considered as the space-time. It is proven that the field strength two-form is gauge covariant and satisfies a deformed Bianchi identity. The noncommutative Yang-Mills action is defined using a gauge covariant metric on the space-time and its gauge invariance is proven up to the second order in the noncommutativity parameter.Comment: Dedicated to Ioan Gottlieb on the occasion of his 80th birthday anniversary. 12 page

Corrections to Schwarzschild Solution in Noncommutative Gauge Theory of Gravity

A deformed Schwarzschild solution in noncommutative gauge theory of gravitation is obtained. The gauge potentials (tetrad fields) are determined up to the second order in the noncommutativity parameters $\Theta^{\mu\nu}$. A deformed real metric is defined and its components are obtained. The noncommutativity correction to the red shift test of General Relativity is calculated and it is concluded that the correction is too small to have observable effects. Implications of such a deformed Schwarzschild metric are also mentioned.Comment: 12 page

Tensor calculus on noncommutative spaces

It is well known that for a given Poisson structure one has infinitely many star products related through the Kontsevich gauge transformations. These gauge transformations have an infinite functional dimension (i.e., correspond to an infinite number of degrees of freedom per point of the base manifold). We show that on a symplectic manifold this freedom may be almost completely eliminated if one extends the star product to all tensor fields in a covariant way and impose some natural conditions on the tensor algebra. The remaining ambiguity either correspond to constant renormalizations to the symplectic structure, or to maps between classically equivalent field theory actions. We also discuss how one can introduce the Riemannian metric in this approach and the consequences of our results for noncommutative gravity theories.Comment: 17p; v2: extended version, to appear in CQ