57,533 research outputs found
Solvable Lattice Gas Models with Three Phases
Phase boundaries in p-T and p-V diagrams are essential in material science
researches. Exact analytic knowledge about such phase boundaries are known so
far only in two-dimensional (2D) Ising-like models, and only for cases with two
phases. In the present paper we present several lattice gas models, some with
three phases. The phase boundaries are either analytically calculated or
exactly evaluated.Comment: 5 pages, 6 figure
Quark Coalescence with Quark Number Conservation and the Effect on Quark-Hadron Scaling
We develop a new formulation of the quark coalescence model by including the
quark number conservation in order to describe the hadronization of the bulk of
the quark-gluon plasma. The scalings between hadron and quark phase space
distributions are shown to depend on the transverse momentum. For hard quarks,
our general scalings reproduce the usual quadratic scaling relation for mesons
and the cubic scaling relation for baryons. For softer quarks, however, the
inclusion of the quark number conservation leads to a linear scaling for the
hadron species that dominates the quark number of each flavor, while the
scalings of non-dominant hadrons depend on the coalescence dynamics. For charm
mesons, we find that the distribution of soft mesons does not depend on the
light quark distribution but the distribution of soft mesons is
inversely correlated to the light quark distribution.Comment: Added 6 more equations to explain the derivations; added discussions;
final published versio
Adaptive just-in-time code diversification
We present a method to regenerate diversified code dynamically in a Java bytecode JIT compiler, and to update the diversification frequently during the execution of the program. This way, we can significantly reduce the time frame in which attackers can let a program leak useful address space information and subsequently use the leaked information in memory exploits. A proof of concept implementation is evaluated, showing that even though code is recompiled frequently, we can achieved smaller overheads than the previous state of the art, which generated diversity only once during the whole execution of a program
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Squeeze-film levitation characteristics of plates excited by piezoelectric actuators
A small mass is levitated by a vibrating plate with an arrangement of four piezoelectric actuators that generate a squeeze-film in the gap between the plate and the mass. Different arrangements of actuators and plate design are explored using simulation in order to produce better performance
Pair Distribution Function of One-dimensional "Hard Sphere" Fermi and Bose Systems
The pair distributions of one-dimensional "hard sphere" fermion and boson
systems are exactly evaluated by introducing gap variables.Comment: 4 page
One-dimensional Ising model built on small-world networks: competing dynamics
In this paper, we offer a competing dynamic analysis of the one-dimensional
Ising model built on the small-world network (SWN). Adding-type SWNs are
investigated in detail using a simplified Hamiltonian of mean-field nature, and
the result of rewiring-type is given because of the similarities of these two
typical networks. We study the dynamical processes with competing Glauber
mechanism and Kawasaki mechanism. The Glauber-type single-spin transition
mechanism with probability p simulates the contact of the system with a heat
bath and the Kawasaki-type dynamics with probability 1-p simulates an external
energy flux. By studying the phase diagram obtained in the present work, we can
realize some dynamical properties influenced by the small-world effect.Comment: 5 pages, one figure, accepted for publication in Physical Review
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Plate actuator vibration modes for levitation
The design of an aluminium or steel plate of various thicknesses for achieving levitation of a small aluminum disk is investigated by simulation using ANSYS. Each plate design is excited by an arrangement of four hard piezoelectric actuators driven with an AC voltage, which produces a centre displacement for generating a squeeze-film in the gap between the vibrating plate and the disk. Physical experiments show levitation conditions for one of the designs
Connections of geometric measure of entanglement of pure symmetric states to quantum state estimation
We study the geometric measure of entanglement (GM) of pure symmetric states
related to rank-one positive-operator-valued measures (POVMs) and establish a
general connection with quantum state estimation theory, especially the maximum
likelihood principle. Based on this connection, we provide a method for
computing the GM of these states and demonstrate its additivity property under
certain conditions. In particular, we prove the additivity of the GM of pure
symmetric multiqubit states whose Majorana points under Majorana representation
are distributed within a half sphere, including all pure symmetric three-qubit
states. We then introduce a family of symmetric states that are generated from
mutually unbiased bases (MUBs), and derive an analytical formula for their GM.
These states include Dicke states as special cases, which have already been
realized in experiments. We also derive the GM of symmetric states generated
from symmetric informationally complete POVMs (SIC~POVMs) and use it to
characterize all inequivalent SIC~POVMs in three-dimensional Hilbert space that
are covariant with respect to the Heisenberg--Weyl group. Finally, we describe
an experimental scheme for creating the symmetric multiqubit states studied in
this article and a possible scheme for measuring the permanent of the related
Gram matrix.Comment: 11 pages, 1 figure, published versio
The ordered K-theory of a full extension
Let A be a C*-algebra with real rank zero which has the stable weak
cancellation property. Let I be an ideal of A such that I is stable and
satisfies the corona factorization property. We prove that 0->I->A->A/I->0 is a
full extension if and only if the extension is stenotic and K-lexicographic. As
an immediate application, we extend the classification result for graph
C*-algebras obtained by Tomforde and the first named author to the general
non-unital case. In combination with recent results by Katsura, Tomforde, West
and the first author, our result may also be used to give a purely
K-theoretical description of when an essential extension of two simple and
stable graph C*-algebras is again a graph C*-algebra.Comment: Version IV: No changes to the text. We only report that Theorem 4.9
is not correct as stated. See arXiv:1505.05951 for more details. Since
Theorem 4.9 is an application to the main results of the paper, the main
results of this paper are not affected by the error. Version III comments:
Some typos and errors corrected. Some references adde
Radius and chirality dependent conformation of polymer molecule at nanotube interface
Temperature dependent conformations of linear polymer molecules adsorbed at
carbon nanotube (CNT) interfaces are investigated through molecule dynamics
simulations. Model polyethylene (PE) molecules are shown to have selective
conformations on CNT surface, controlled by atomic structures of CNT lattice
and geometric coiling energy. PE molecules form entropy driven assembly
domains, and their preferred wrapping angles around large radius CNT (40, 40)
reflect the molecule configurations with energy minimums on a graphite plane.
While PE molecules prefer wrapping on small radius armchair CNT (5, 5)
predominantly at low temperatures, their configurations are shifted to larger
wrapping angle ones on a similar radius zigzag CNT (10, 0). A nematic
transformation around 280 K is identified through Landau-deGennes theory, with
molecule aligning along tube axis in extended conformationsComment: 19 pages, 7 figure2, submitted to journa
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