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Abstrak :
Telah dihitung polarisasi, penampang lintang diferensial dan jalan bebas rata-rata pada interaksi neutrino-gas elektron dengan mempertimbangkan faktor bentuk elektromagnetik neutrino, untuk temperahu' berhingga. Faktor- faktor yang dipertimbangkan pada perhitungan adalah retardasi, detail balans dan Pauli bloking serta anti partikel. Efek banyak benda masuk dalam perhitungan polarisasi melalui pendekatan korelasi fase random ( random phase approximation ) dan massa foton efktif. Hasil yang didapat digunakan untuk mempelajari interaksi neutrino dengan materi pada atmosfir Supernova. Hasil penelitian ini menunjukkan seberapa besar pengaruh faktor-faktor temperatur, kerapatan elektron, momen dipol neutrino, jari-jari muatan neutrino, korelasi random phase approximation, massa foton efektif dan koreksi relativitas umum pada jalan bebas rata-rata neutrino pada atmosfir supernova. ......The polarizations, differential cross section and mean free path of neutrino-electron gas interaction have been calculated by taking into account the neutrino electromagnetic form factor, for finite temperature. 'The retarded, detailed balance, Pauli blocking and anti-particle factors have been also taken into account in the calculations. Many~body effects enter into polarizations calculations through random phase approximation correlation and photon effective mass. The results are used to study the interaction of neutrino with matter in supernova atmosphere. It has also shown how large the influence of temperature, electron density, neutrino moment dipole, neutrino charge radius, random phase approximation correlation, photon effective mass and general relativity correction in mean free path at supernova atmosphere.

Abstrak :
Termotivasi untuk memperluas studi teoritis yang pernah dilakukan sebelumnya, kami melakukan perhitungan konduktivitas optik tergantung temperatur pada La0:7Ca0:3MnO3 dalam rentang energi foton yang luas hingga 22 eV, untuk menangkap transisi logam ke insulator, dengan tetap mempertahankan profil ketergantungan terhadap temperatur yang sesuai dengan data eksperimen pada energi foton yang lebih tinggi. Sistem dimodelkan dengan koordinasi Mn-O sederhana melalui metode tight binding dengan beberapa integral hopping dianggap sebagai fungsi magnetisasi. Menggabungkan efek Jahn-Teller statis, Coulomb-Hubbard dan interaksi pertukaran magnetik, kami dapat mereproduksi tren kualitatif dari konduktivitas optik yang tergantung pada suhu, terutama untuk rezim energi rendah dan tinggi, seperti yang diamati dalam data eksperimen. Hasil kami menggarisbawahi pentingnya efek korelasi yang saling mempengaruhi pada derajat kebebasan kisi, muatan dan magnet dalam menentukan profil keseluruhan respon optik terhadap temperatur dari manganite, hubungannya dengan respon fisika optik energi tinggi dan sifat transpor listrik DC. ...... Motivated to extend our previous theoretical study, we perform temperaturedependent optical conductivity calculation on La0:7Ca0:3MnO3 in a wide photon energy range up to 22 eV, to capture the metal to insulator transition, while still preserving in most way the correct temperature-dependent profile at higher photon energies. The system is modeled with a simple Mn-O coordination via the tight binding method with some hopping integrals being considered as functions of magnetization. Incorporating static Jahn-Teller effect, Coulomb-Hubbard and magnetic exchange interactions, we are able to reproduce the qualitative trend of the temperature-dependent optical conductivity, especially for the low-and high-energy regimes, as observed in the experimental data. Our results underline the importance of correlation effects due to interplay of lattice, charge, and magnetic degrees of freedom in determining the overall profile of temperature-dependent optical response of manganites, connecting the physics of high-energy optical response and the transport properties at the dc limit.

Abstrak :
The differential cross-section of neutrino interaction with dense and warm electron gasses has been calculated by taking into account the neutrino electromagnetic form factors. The significant effect of electromagnetic properties of neutrino can be found if the neutrino dipole moment, μν, is ≥5.10-9 μB and neutrino charge radius, Rv, is ≥5.10-6MeV-1. The importance of the retarded correction, detailed balance and Pauli blocking factors is shown and analyzed. Many-body effects on the target matter which are included via random phase approximation (RPA) correlation as well as photon effective mass are also investigated.