Local Energy Gap in Deformed Carbon Nanotubes

The effects of graphite surface geometrical deformation on the dynamics of conducting electrons are investigated theoretically. The analysis is performed within the framework of a deformation-induced gauge field and corresponding deformation-induced magnetic field. It is shown that the latter gives a local energy gap along the axis of a deformed nanotube. We compare our energy gap results with experimental data on energy gaps in nanotubes and peapods. We also discuss the mixing of two Fermi points and construct a general model of low energy dynamics, including a short-range deformation of the graphite sheet. This model is equivalent to the Weyl equation in {\it U}(1) Abelian and {\it SU}(2) non-Abelian deformation-induced gauge fields.Comment: 18 pages, 4 figures, corrected typos, added references, improved presentation (v4, published version

Statics and dynamics of phase segregation in multicomponent fermion gas

We investigate the statics and dynamics of spatial phase segregation process of a mixture of fermion atoms in a harmonic trap using the density functional theory. The kinetic energy of the fermion gas is written in terms of the density and its gradients. Several cases have been studied by neglecting the gradient terms (the Thomas-Fermi limit) which are then compared with the Monte-Carlo results using the full gradient corrected kinetic energy. A linear instability analysis has been performed using the random-phase approximation. Near the onset of instability, the fastest unstable mode for spinodal decomposition is found to occur at $q=0$. However, in the strong coupling limit, many more modes with $q\approx K_F$ decay with comparable time scales.Comment: 14 figure

Controlling edge states of zigzag carbon nanotubes by the Aharonov-Bohm flux

It has been known theoretically that localized states exist around zigzag edges of a graphite ribbon and of a carbon nanotube, whose energy eigenvalues are located between conduction and valence bands. We found that in metallic single-walled zigzag carbon nanotubes two of the localized states become critical, and that their localization length is sensitive to the mean curvature of a tube and can be controlled by the Aharonov-Bohm flux. The curvature induced mini-gap closes by the relatively weak magnetic field. Conductance measurement in the presence of the Aharonov-Bohm flux can give information about the curvature effect and the critical states.Comment: 5 pages, 4 figure

Ferroelectric Phase Transitions in Ultra-thin Films of BaTiO3

We present molecular dynamics simulations of a realistic model of an ultrathin film of BaTiO$_3$ sandwiched between short-circuited electrodes to determine and understand effects of film thickness, epitaxial strain and the nature of electrodes on its ferroelectric phase transitions as a function of temperature. We determine a full epitaxial strain-temperature phase diagram in the presence of perfect electrodes. Even with the vanishing depolarization field, we find that ferroelectric phase transitions to states with in-plane and out-of-plane components of polarization exhibit dependence on thickness; it arises from the interactions of local dipoles with their electrostatic images in the presence of electrodes. Secondly, in the presence of relatively bad metal electrodes which only partly compensate the surface charges and depolarization field, a qualitatively different phase with stripe-like domains is stabilized at low temperature

Stability and Reactivity of C60 Studied by All-Electron Mixed-Basis Molecular-Dynamics Simulations at Finite Temperatures

Usia remaja dipandang sebagai usia bermasalah, karena pada masa ini remaja dihadapkan pada banyak persoalan dan cenderung dihadapi secara emosional. Pergolakan emosi yang terjadi pada remaja tidak terlepas dari bermacam pengaruh, seperti lingkungan tempat tinggal, keluarga, sekolah dan teman-teman sebaya. Tidak terpenuhinya tuntutan gejolak energinya, maka remaja seringkali meluapkan kelebihan energinya ke arah yang negatif (perilaku agresif). Dalam rangka menghadapi hal-hal negatif yang dapat merugikan remaja, remaja hendaknya memahami dan memiliki apa yang disebut kecerdasan emosional. Penelitian ini bertujuan untuk megetahui hubungan antara kecerdasan emosional dengan perilaku agresif remaja. Penelitian ini adalah deskriptif analitik dengan pendekatan cross sectional yang dilakukan pada bulan Oktober 2009-Oktober 2010 di SMKN 5 Padang. Pengambilan sampel dilakukan secara proposional random sampling dengan jumlah sampel 260 responden. Instrumen yang digunakan adalah kuesioner yang yang telah di uji dengan uji validitas dan reliabilitas. Hasil dari uji coba kuesioner didapatkan Reliabilitas skala kecerdasan emosional sebesar 0,938. Untuk skala perilaku agresif, diadopsi dari kuesioner agresi yang di susun oleh Buss, & Perry. Pengolahan data dilakukan dengan analisa univariat dan bivariat dengan uji hipotesis Spearman. Berdasarkan hasil penelitian, 55,8% siswa mempunyai kecerdasan emosional rendah, 61,9% siswa mempunyai prilaku agresif yang tinggi. Dari hasil statistik diperoleh nilai korelasi Spearman sebesar -0,666 dengan signifikasi sebesar 0,000 (p<0,05). Berdasarkan penelitian dapat disimpulkan bahwa semakin rendah kecerdasan emosional siswa maka semakin tinggi prilaku agresif siswa. Oleh karena itu perlu merealisasikan rencana pelatihan ESQ (Emotional Spiritual Quotient) sehingga siswa mampu mengendalikan dorongan emosinya dan dapat mengarahkan emosinya ke hal-hal yang positif. Kata kunci : Kecerdasan emosional, remaja, prilaku agresi

The Experimental plan of the 4m Resonant Sideband Extraction Prototype for The LCGT

The 4m Resonant Sideband Extraction (RSE) interferometer is a planned prototype of the LCGT interferometer. The aim of the experiment is to operate a powerrecycled Broadband RSE interferometer with suspended optics and to achieve diagonalization of length signals of the central part of the interferometer directly through the optical setup. Details of the 4m RSE interferometer control method as well as the design of the experimental setup will be presented