963 research outputs found
Freezing of an unconventional two-dimensional plasma
We study an unconventional two-dimensional, two-component classical plasma on
a sphere, with emphasis on detecting signatures of melting transitions. This
system is relevant to Ising-type quantum Hall states, and is unconventional in
the sense that it features particles interacting via two different
two-dimensional Coulomb interactions. One species of particles in the plasma
carries charge of both types (Q_1,Q_2), while the other species carries only
charge of the second type (0,-Q_2). We find signatures of a freezing transition
at Q_1^2 approximately 140. This means that the species with charge of both
types will form a Wigner crystal, whereas the species with charge of the second
type also shows signatures of being a Wigner crystal, due to the attractive
inter-component interaction of the second type. Moreover, there is also a
Berezinskii-Kosterlitz-Thouless phase transition at Q_2^2 approximately 4, at
which the two species of particles bind to form molecules that are neutral with
respect to the second Coulomb interaction. These two transitions appear to be
independent of each other, giving a rectangular phase diagram. As a special
case, Q_2=0 describes the (conventional) two-dimensional one-component plasma.
Our study is consistent with previous studies of this plasma, and sheds new
light on the freezing transition of this system.Comment: 8 pages, 8 figures. Submitted to Physical Review
Detecting Non-Abelian Statistics in the nu=5/2 Fractional Quantum Hall State
In this letter we propose an interferometric experiment to detect non-Abelian
quasiparticle statistics -- one of the hallmark characteristics of the
Moore-Read state expected to describe the observed FQHE plateau at nu=5/2. The
implications for using this state for constructing a topologically protected
qubit as has been recently proposed by Das Sarma et. al. are also addressed.Comment: 5 pages, 2 eps figures v2: A few minor changes and citation
corrections. In particular, the connection to cond-mat/9711087 has been
clarified. v3: Minor changes: fixed references to Fig. 2, updated citations,
changed a few words to conform to the version published in PR
Screening properties and phase transitions in unconventional plasmas for Ising-type quantum Hall states
Utilizing large-scale Monte-Carlo simulations, we investigate an
unconventional two-component classical plasma in two dimensions which controls
the behavior of the norms and overlaps of the quantum-mechanical wavefunctions
of Ising-type quantum Hall states. The plasma differs fundamentally from that
which is associated with the two-dimensional XY model and Abelian fractional
quantum Hall states. We find that this unconventional plasma undergoes a
Berezinskii-Kosterlitz-Thouless phase transition from an insulator to a metal.
The parameter values corresponding to Ising-type quantum Hall states lie on the
metallic side of this transition. This result verifies the required properties
of the unconventional plasma used to demonstrate that Ising-type quantum Hall
states possess quasiparticles with non-Abelian braiding statistics.Comment: 16 pages, 14 figures. Submitted to Physical Review
Techniques for data prediction, smoothing, and updating of operator errors in commercial nuclear power plants
http://www.worldcat.org/oclc/533896
Formalism for chaotic behavior of the bunched beam
Using Cesaro mid of Fourier series the quasi-linear Vlasov’s equation is transformed to the integral Fredholm equation. New results on the oscillatory behavior of solution are obtained. An extension to perturbing equation is also included
Global-in-time solutions of 3-dimensional Vlasov-Poisson system
In this paper, we consider 3-dimensional Vlasov-Poisson system and study their qualitative properties of globalin-time
solutions from the point of view integrability, stability, and optimality using the concept of special constructed
integral equations and the Lyapunov direct method. We provide criteria that guarantee the existence of solution
for the above mentioned properties By using this approach we reduce the problem of the charged-particle beam
transport, in particular, focusing with acceleration, to a problem of optimal control of dynamic system.В этой работе мы рассматриваем 3-х мерную систему уравнений Власова-Пуассона и изучаем качественные свойства их глобальных во времени решений с точки зрения интегрируемости, устойчивости и оптимальности использования концепции специально сконструированных интегральных уравнений и прямого метода Ляпунова. Мы приводим критерии, которые гарантируют существование решения для вышеупомянутых свойств. Благодаря использованию этого подхода мы свели проблему транспорта пучка заряженных частиц, в частности, фокусировку с ускорением к задаче оптимального управления динамической системой.В цій роботі ми розглядаємо 3-и вимірну систему рівнянь Власова-Пуассона та вивчаємо якісні
властивості їх глобальних за часом розв’язків з точки зору інтегрованості, стійкості і оптимальності
використання концепції спеціально сконструйованих інтегральних рівнянь та прямого методу Ляпунова. Ми
приводимо критерії, котрі гарантують існування розв’язків для вищезазначених властивостей. Завдяки
застосуванню цього підходу ми звели проблему транспорту пучка заряджених частинок, зокрема,
фокусування з прискоренням до задачі оптимального керування динамічною системою
Plasma Analogy and Non-Abelian Statistics for Ising-type Quantum Hall States
We study the non-Abelian statistics of quasiparticles in the Ising-type
quantum Hall states which are likely candidates to explain the observed Hall
conductivity plateaus in the second Landau level, most notably the one at
filling fraction nu=5/2. We complete the program started in Nucl. Phys. B 506,
685 (1997) and show that the degenerate four-quasihole and six-quasihole
wavefunctions of the Moore-Read Pfaffian state are orthogonal with equal
constant norms in the basis given by conformal blocks in a c=1+1/2 conformal
field theory. As a consequence, this proves that the non-Abelian statistics of
the excitations in this state are given by the explicit analytic continuation
of these wavefunctions. Our proof is based on a plasma analogy derived from the
Coulomb gas construction of Ising model correlation functions involving both
order and (at most two) disorder operators. We show how this computation also
determines the non-Abelian statistics of collections of more than six
quasiholes and give an explicit expression for the corresponding conformal
block-derived wavefunctions for an arbitrary number of quasiholes. Our method
also applies to the anti-Pfaffian wavefunction and to Bonderson-Slingerland
hierarchy states constructed over the Moore-Read and anti-Pfaffian states.Comment: 68 pages, 3 figures; v2: substantial revisions and additions for
clarity, minor correction
Nuclear Activity and the Conditions of Star-formation at the Galactic Center
The Galactic Center is the closest galactic nucleus that can be studied with
unprecedented angular resolution and sensitivity. We summarize recent basic
observational results on Sagittarius A* and the conditions for star formation
in the central stellar cluster. We cover results from the radio, infrared, and
X-ray domain and include results from simulation as well. From (sub-)mm and
near-infrared variability and near-infrared polarization data we find that the
SgrA* system (supermassive black hole spin, a potential temporary accretion
disk and/or outflow) is well ordered in its geometrical orientation and in its
emission process that we assume to reflect the accretion process onto the
supermassive black hole (SMBH).Comment: 11 pages, 4 figures, 1 table; published in PoS-SISSA Proceedings of
the: Frontier Research in Astrophysics - II, 23-28 May 2016, Mondello
(Palermo), Ital
Akt and SHIP Modulate Francisella Escape from the Phagosome and Induction of the Fas-Mediated Death Pathway
Francisella tularensis infects macrophages and escapes phago-lysosomal fusion to replicate within the host cytosol, resulting in host cell apoptosis. Here we show that the Fas-mediated death pathway is activated in infected cells and correlates with escape of the bacterium from the phagosome and the bacterial burden. Our studies also demonstrate that constitutive activation of Akt, or deletion of SHIP, promotes phago-lysosomal fusion and limits bacterial burden in the host cytosol, and the subsequent induction of Fas expression and cell death. Finally, we show that phagosomal escape/intracellular bacterial burden regulate activation of the transcription factors sp1/sp3, leading to Fas expression and cell death. These data identify for the first time host cell signaling pathways that regulate the phagosomal escape of Francisella, leading to the induction of Fas and subsequent host cell death
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