Ipteks Om-span Pada Direktorat Jenderal Perbendaharaan Negara Sulawesi Utara

This report shows how modernization greatly influences the performance carried out, which makes work easier and faster precisely. using the online monitoring application SPAN on the performance of employees at the directorate general of the state of North Sulawesi, especially in the internal part of the company to be more efficient in monitoring stakeholders. this report is compiled descriptively and qualitative data collection. the results of which affect work, resulting in satisfactory work results in the directorate general of the state treasury of North Sulawesi

Domain Patterns in the Microwave-Induced Zero-Resistance State

It has been proposed that the microwave-induced ``zero-resistance'' phenomenon, observed in a GaAs two-dimensional electron system at low temperatures in moderate magnetic fields, results from a state with multiple domains, in which a large local electric field \bE(\br) is oriented in different directions. We explore here the questions of what may determine the domain arrangement in a given sample, what do the domains look like in representative cases, and what may be the consequences of domain-wall localization on the macroscopic dc conductance. We consider both effects of sample boundaries and effects of disorder, in a simple model, which has a constant Hall conductivity, and is characterized by a Lyapunov functional.Comment: 19 pages, 5 figures; submitted to a special issue of Journal of Statistical Physics, in honor of P. C. Hohenberg and J. S. Lange

Spin Tunneling, Berry phases and Doped Antiferromagnets

Interference effects between Berry phase factors in spin tunneling systems have been discussed in recent Letters by Loss, DiVincenzo and Grinstein and von Delft and Henley. This Comment points out that Berry phases in spin tunneling are important in another interesting case: the two dimensional doped antiferromagnet. I show that the dispersion of a single hole in the t-J model changes sign as $e^{2\pi s}$ where $s$ is the size of the spins. This provides an interpretation of the numerical results for the s=\half model, and a prediction for other spin sizes.Comment: 5 pages, LaTe

Oscillating Superfluidity of Bosons in Optical Lattices

We follow up on a recent suggestion by C. Orzel et. al., Science, 291, 2386 (2001), whereby bosons in an optical lattice would be subjected to a sudden parameter change from the Mott to the superfluid phase. We analyze the Bose Hubbard model with a modified coherent states path integral which can escribe - both - phases. The saddle point theory yields collective oscillations of the uniform superfluid order parameter. These would be seen in time resolved interference patterns made by the released gas. We calculate the collective oscillation's damping rate by phason pair emission. In two dimensions the overdamped region largely overlaps with the quantum critical region. Measurements of critical dynamics on the Mott side are proposed.Comment: 4 pages 1 eps figures; Final version as appears in PRL. Added discussion on spontaneous generation of vortice

Polarization transitions in interacting ring 1D arrays

Periodic nanostructures can display the dynamics of arrays of atoms while enabling the tuning of interactions in ways not normally possible in Nature. We examine one dimensional arrays of a ``synthetic atom,'' a one dimensional ring with a nearest neighbor Coulomb interaction. We consider the classical limit first, finding that the singly charged rings possess antiferroelectric order at low temperatures when the charge is discrete, but that they do not order when the charge is treated as a continuous classical fluid. In the quantum limit Monte Carlo simulation suggests that the system undergoes a quantum phase transition as the interaction strength is increased. This is supported by mapping the system to the 1D transverse field Ising model. Finally we examine the effect of magnetic fields. We find that a magnetic field can alter the electrostatic phase transition producing a ferroelectric groundstate, solely through its effect of shifting the eigenenergies of the quantum problem.Comment: 12 pages in two column format, 18 figure

Generalized Elitzur's Theorem and Dimensional Reduction

We extend Elitzur's theorem to systems with symmetries intermediate between global and local. In general, our theorem formalizes the idea of {\it dimensional reduction}. We apply the results of this generalization to many systems that are of current interest. These include liquid crystalline phases of Quantum Hall systems, orbital systems, geometrically frustrated spin lattices, Bose metals, and models of superconducting arrays.Comment: 10 pages, 1 figur

Effective Spin Quantum Phases in Systems of Trapped Ions

A system of trapped ions under the action of off--resonant standing--waves can be used to simulate a variety of quantum spin models. In this work, we describe theoretically quantum phases that can be observed in the simplest realization of this idea: quantum Ising and XY models. Our numerical calculations with the Density Matrix Renormalization Group method show that experiments with ion traps should allow one to access general properties of quantum critical systems. On the other hand, ion trap quantum spin models show a few novel features due to the peculiarities of induced effective spin--spin interactions which lead to interesting effects like long--range quantum correlations and the coexistence of different spin phases.Comment: 11 pages, 13 figure