Search for exact local Hamiltonians for general fractional quantum Hall states

We report on our systematic attempts at finding local interactions for which the lowest-Landau-level projected composite-fermion wave functions are the unique zero energy ground states. For this purpose, we study in detail the simplest non-trivial system beyond the Laughlin states, namely bosons at filling $\nu=\frac{2}{3}$ and identify local constraints among clusters of particles in the ground state. By explicit calculation, we show that no Hamiltonian up to (and including) four particle interactions produces this state as the exact ground state, and speculate that this remains true even when interaction terms involving greater number of particles are included. Surprisingly, we can identify an interaction, which imposes an energetic penalty for a specific entangled configuration of four particles with relative angular momentum of $6\hbar$, that produces a unique zero energy solution (as we have confirmed for up to 12 particles). This state, referred to as the $\lambda$-state, is not identical to the projected composite-fermion state, but the following facts suggest that the two might be topologically equivalent: the two sates have a high overlap; they have the same root partition; the quantum numbers for their neutral excitations are identical; and the quantum numbers for the quasiparticle excitations also match. On the quasihole side, we find that even though the quantum numbers of the lowest energy states agree with the prediction from the composite-fermion theory, these states are not separated from the others by a clearly identifiable gap. This prevents us from making a conclusive claim regarding the topological equivalence of the $\lambda$ state and the composite-fermion state. Our study illustrates how new candidate states can be identified from constraining selected many particle configurations and it would be interesting to pursue their topological classification.Comment: 21 pages, 11 figure

Fractional statistics in the fractional quantum Hall effect

A microscopic confirmation of the fractional statistics of the {\em quasiparticles} in the fractional quantum Hall effect has so far been lacking. We calculate the statistics of the composite-fermion quasiparticles at $\nu=1/3$ and $\nu=2/5$ by evaluating the Berry phase for a closed loop encircling another composite-fermion quasiparticle. A careful consideration of subtle perturbations in the trajectory due to the presence of an additional quasiparticle is crucial for obtaining the correct value of the statistics. The conditions for the applicability of the fractional statistics concept are discussed.Comment: Phys. Rev. Lett., in pres

Pengaruh Budaya Organisasi, Teknologi Informasi, dan Sistem Informasi Akuntansi Manajemen terhadap Kinerja Manajerial PT. Propan Raya I.c.c Cab. Bandung

Penelitian ini bertujuan untuk mengetahui adanya pengaruh budaya organisasi, teknologi informasi dan sistem informasi akuntansi manajemen terhadap kinerja manajerial. Populasi dalam  penelitian ini manajer karyawan PT. Propan Raya I.C.C Cab. Bandung. Penelitian ini menggunakan metode survey dengan jumlah responden karyawan manajer. Data penelitian merupakan data primer dan metode pengumpulan data menggunakan kuesioner. Hasil penelitian menunjukan bahwa: 1) Budaya organisasi berpengaruh terhadap kinerja manajerial 2) Teknologi informasi berpengaruh signifikan terhadap kinerja manajerial 3) sistem akuntansi informasi manajemen berpengaruh signifikan terhadap kinerja manajerial

Tyrosine dephosphorylation of H2AX modulates apoptosis and survival decisions.

Life and death fate decisions allow cells to avoid massive apoptotic death in response to genotoxic stress. Although the regulatory mechanisms and signalling pathways controlling DNA repair and apoptosis are well characterized, the precise molecular strategies that determine the ultimate choice of DNA repair and survival or apoptotic cell death remain incompletely understood. Here we report that a protein tyrosine phosphatase, EYA, is involved in promoting efficient DNA repair rather than apoptosis in response to genotoxic stress in mammalian embryonic kidney cells by executing a damage-signal-dependent dephosphorylation of an H2AX carboxy-terminal tyrosine phosphate (Y142). This post-translational modification determines the relative recruitment of either DNA repair or pro-apoptotic factors to the tail of serine phosphorylated histone H2AX (gamma-H2AX) and allows it to function as an active determinant of repair/survival versus apoptotic responses to DNA damage, revealing an additional phosphorylation-dependent mechanism that modulates survival/apoptotic decisions during mammalian organogenesis

Spatiotemporal Stochastic Resonance in Fully Frustrated Josephson Ladders

We consider a Josephson-junction ladder in an external magnetic field with half flux quantum per plaquette. When driven by external currents, periodic in time and staggered in space, such a fully frustrated system is found to display spatiotemporal stochastic resonance under the influence of thermal noise. Such resonance behavior is investigated both numerically and analytically, which reveals significant effects of anisotropy and yields rich physics.Comment: 8 pages in two columns, 8 figures, to appear in Phys. Rev.