1,289 research outputs found
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 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 , that produces a unique zero energy solution (as
we have confirmed for up to 12 particles). This state, referred to as the
-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 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
and 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.
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