3,981 research outputs found
Multiscaling in Ising quantum chains with random Hilhorst-van Leeuwen perturbations
We consider the influence on the surface critical behaviour of a quantum
Ising chain of quenched random surface perturbations decaying as a power of the
distance from the surface (random Hilhorst-van Leeuwen models). We study,
analytically and numerically, the multiscaling behaviour of the surface
magnetization and the surface energy density in the case of marginal
perturbations.Comment: 14 pages, 5 figures, LaTeX2e, epsf, elsar
A nonperturbative Real-Space Renormalization Group scheme
Based on the original idea of the density matrix renormalization group
(DMRG), i.e. to include the missing boundary conditions between adjacent blocks
of the blocked quantum system, we present a rigorous and nonperturbative
mathematical formulation for the real-space renormalization group (RG) idea
invented by L.P. Kadanoff and further developed by K.G. Wilson. This is
achieved by using additional Hilbert spaces called auxiliary spaces in the
construction of each single isolated block, which is then named a superblock
according to the original nomenclature. On this superblock we define two maps
called embedding and truncation for successively integrating out the small
scale structure. Our method overcomes the known difficulties of the numerical
DMRG, i.e. limitation to zero temperature and one space dimension.Comment: 13 pages, 5 figures, late
Effects of pressure, oxygen concentration, and forced convection on flame spread rate of Plexiglas, Nylon and Teflon
Experiments were conducted in which the burning of cylindrical materials in a flowing oxidant stream was studied. Plexiglas, Nylon, and Teflon fuel specimens were oriented such that the flames spread along the surface in a direction opposed to flowing gas. Correlations of flame spread rate were obtained that were power law relations in terms of pressure, oxygen concentration, and gas velocity
CLIC Muon Sweeper Design
There are several background sources which may affect the analysis of data
and detector performans at the CLIC project. One of the important background
source is halo muons, which are generated along the beam delivery system (BDS),
for the detector performance. In order to reduce muon background, magnetized
muon sweepers have been used as a shielding material that is already described
in a previous study for CLIC [1]. The realistic muon sweeper has been designed
with OPERA. The design parameters of muon sweeper have also been used to
estimate muon background reduction with BDSIM Monte Carlo simulation code [2,
3].Comment: Talk presented at the International Workshop on Future Linear
Colliders (LCWS15), Whistler, Canada, 2-6 November 2015, 7 pages, 6 figure
Simulation of two-dimensional quantum systems using a tree tensor network that exploits the entropic area law
This work explores the use of a tree tensor network ansatz to simulate the
ground state of a local Hamiltonian on a two-dimensional lattice. By exploiting
the entropic area law, the tree tensor network ansatz seems to produce
quasi-exact results in systems with sizes well beyond the reach of exact
diagonalisation techniques. We describe an algorithm to approximate the ground
state of a local Hamiltonian on a L times L lattice with the topology of a
torus. Accurate results are obtained for L={4,6,8}, whereas approximate results
are obtained for larger lattices. As an application of the approach, we analyse
the scaling of the ground state entanglement entropy at the quantum critical
point of the model. We confirm the presence of a positive additive constant to
the area law for half a torus. We also find a logarithmic additive correction
to the entropic area law for a square block. The single copy entanglement for
half a torus reveals similar corrections to the area law with a further term
proportional to 1/L.Comment: Major rewrite, new version published in Phys. Rev. B with highly
improved numerical results for the scaling of the entropies and several new
sections. The manuscript has now 19 pages and 30 Figure
Creating A Normalized Montessori Classroom
The purpose of this report is to describe the findings of a study on how the implementation of the Accelerated Reader Program, use of five different management strategies, as well as the introduction of routines and rituals affects students\u27 ability to create a normalized 1st through 3rd grade Montessori classroom. The research was conducted with a lower elementary Montessori classroom within a public school setting. More than half of the students had never experienced a Montessori environment. The data collecting methods used were a summative assessment, tally sheets, field notes, attitude scale inquiries, and semi-structured conversations with the students. The results of this research indicated only a marginal increase in a positive direction toward a normalized class. A large part of the difficulty in reaching a normalized class was due to the lack of ability to concentrate on work because of noise in the classroom. The implications of this action plan include reducing extraneous distractions, increasing positive reinforcement, and teaching more time management and self-monitoring skills
Beam-size effect and particle losses at Super factory (Italy)
In the colliders, the macroscopically large impact parameters give a
substantial contribution to the standard cross section of the process. These impact parameters may be much larger than the
transverse sizes of the colliding bunches. It means that the standard cross
section of this process has to be substantially modified. In the present paper
such a beam-size effect is calculated for bremsstrahlung at Super factory
developed in Italy. We find out that this effect reduces beam losses due to
bremsstrahlung by about 40%.Comment: 11 pages, 4 figure
Conformal off-diagonal boundary density profiles on a semi-infinite strip
The off-diagonal profile phi(v) associated with a local operator (order
parameter or energy density) close to the boundary of a semi-infinite strip
with width L is obtained at criticality using conformal methods. It involves
the surface exponent x_phi^s and displays a simple universal behaviour which
crosses over from surface finite-size scaling when v/L is held constant to
corner finite-size scaling when v/L -> 0.Comment: 5 pages, 1 figure, IOP macros and eps
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