Phase coherence and the Nernst effect at magic angles in organic conductors

A giant Nernst signal was recently observed for fields near crystallographic directions in (TMTSF)$_2$PF$_6$. Such large Nernst signals are most naturally associated with the motion of pancake vortices. We propose a model in which phase coherence is destroyed throughout the sample except in planes closely aligned with the applied field $\bf H$. A small tilt above or below the plane changes the direction and density of the penetrating vortices and leads to a Nernst signal that varies with the tilt angle of $\bf H$ as observed. The resistance notches at magic angles are understood in terms of flux-flow dissipation from field-induced vortices.Comment: 4 pages, 4 figure

Efektifitas Program Pusat Kegiatan Belajar Masyarakat Dinas Pendidikan Kota Manado dalam Meningkatkan Sumber Daya Manusia1

Dijelaskan dalam Bab 1 Pasal 1 Undang-Undang no 20 tahun 2003 tentang sistempendidikan nasional, pendidikan adalah USAha sadar dan berencana untuk mewujudkan suasanabelajar dan proses pembelajaran agar peserta didik secara aktif mengembangkan potensi dirinyauntuk memiliki kekuatan spiritual keagamaan, pengendalian diri, kepribadian , kecerdasan ,akhlak mulia serta ketrampilan yang diperlukan dirinya, masyarakat, bangsa dan negara.Pendidikan termasuk dalam kegiatan investasi masa depan. Investasi pendidikan padaumumnya dilakukan sejak usia anak-anak sampai usia muda atau pemuda. Pendidikanmerupakan faktor yang berkaitan langsung dengan pemuda mengingat usia muda merupakanusia sekolah. Problem yang terutama muncul adalah penyediaan fasilitas pendidikan meliputigedung sekolah, tenaga guru, buku-buku dan lain sarana pendidikan dalam jumlah yang lebihbanyak. Didapati berdasarkan data yang ada bahwa rendahnya pendidikan di Indonesiadisebabkan oleh berbagai faktor. Biaya pendidikan yang mahal dan dan terus meningkatdianggap sebagai faktor utama namun secara psikologis didapati juga faktor yang beranggapanbahwa juga pendidikan tidak dianggap penting karena tidak bisa menghasilkan peningkatanekonomi.Efektifitas pendidikan dalam hal ini karakter tidak cukup hanya dilaksanakan disekolah ataulembaga-lembaga formal. Bahkan dalam langkah selajutnya pendidikan perlu dilaksanakan olehseluruh lapisan masyarakat diseluruh instansi pemerintah, ormas, parpol, lembaga swadayamasyarakat dan kelompok masyarakat Pusat Kegiatan Belajar Masyarakat

The Nernst effect in high-TcT_c superconductors

The observation of a large Nernst signal $e_N$ in an extended region above the critical temperature $T_c$ in hole-doped cuprates provides evidence that vortex excitations survive above $T_c$. The results support the scenario that superfluidity vanishes because long-range phase coherence is destroyed by thermally-created vortices (in zero field), and that the pair condensate extends high into the pseudogap state in the underdoped (UD) regime. We present a series of measurements to high fields $H$ which provide strong evidence for this phase-disordering scenario.Comment: 21 pages, 28 figure

Unusual Nernst effect suggestive of time-reversal violation in the striped cuprate La2−x_{2-x}Bax_xCuO4_4

The striped cuprate La$_{2-x}$Ba$_x$CuO$_4$ ($x=\frac18)$ undergoes several transitions below the charge-ordering temperature $T_{co}$ = 54 K. From Nernst experiments, we find that, below $T_{co}$, there exists a large, anomalous Nernst signal $e_{N,even}(H,T)$ that is symmetric in field $H$, and remains finite as $H\to 0$. The time-reversal violating signal suggests that, below $T_{co}$, vortices of one sign are spontaneously created to relieve interlayer phase frustration.Comment: 5 pages, 4 figure

A 3-D Multilateration: A Precision Geodetic Measurement System

A system was designed with the capability of determining 1-cm accuracy station positions in three dimensions using pulsed laser earth satellite tracking stations coupled with strictly geometric data reduction. With this high accuracy, several crucial geodetic applications become possible, including earthquake hazards assessment, precision surveying, plate tectonics, and orbital determination

Field-Tuning of the electron and hole populations in the ruthenate Bi_3Ru_3O_11

Experiments on the Hall coefficient R_H and heat capactity C reveal an unusual, compensated electronic ground state in the ruthenate Bi_3Ru_3O_11. At low temperature T, R_H decreases linearly with magnetic field |H| for fields larger than the field scale set by the Zeeman energy. The results suggest that the electron and hole populations are tuned by H in opposite directions via coupling of the spins to the field. As T is decreased below 5 K, the curve C(T)/T vs. T^2 shows an anomalous flattening consistent with a rapidly growing Sommerfeld parameter \gamma(T). We discuss shifts of the electron and hole chemical potentials by H to interpret the observed behavior of R_H.Comment: 5 pages, 6 figures, reference adde

Heat capacity anomaly at the quantum critical point of the Transverse Ising Magnet CoNb_2O_6

The transverse Ising magnet Hamiltonian describing the Ising chain in a transverse magnetic field is the archetypal example of a system that undergoes a transition at a quantum critical point (QCP). The columbite CoNb$_2$O$_6$ is the closest realization of the transverse Ising magnet found to date. At low temperatures, neutron diffraction has observed a set of discrete collective spin modes near the QCP. We ask if there are low-lying spin excitations distinct from these relatively high energy modes. Using the heat capacity, we show that a significant band of gapless spin excitations exists. At the QCP, their spin entropy rises to a prominent peak that accounts for 30$\%$ of the total spin degrees of freedom. In a narrow field interval below the QCP, the gapless excitations display a fermion-like, temperature-linear heat capacity below 1 K. These novel gapless modes are the main spin excitations participating in, and affected, by the quantum transition.Comment: 14 pages total, 8 figure

Three-D multilateration: A precision geodetic measurement system

A technique of satellite geodesy for determining the relative three dimensional coordinates of ground stations within one centimeter over baselines of 20 to 10,000 kilometers is discussed. The system is referred to as 3-D Multilateration and has applications in earthquake hazard assessment, precision surveying, plate tectonics, and orbital mechanics. The accuracy is obtained by using pulsed lasers to obtain simultaneous slant ranges between several ground stations and a moving retroreflector with known trajectory for aiming the lasers