3,474 research outputs found
Entanglement, subsystem particle numbers and topology in free fermion systems
We study the relationship between bipartite entanglement, subsystem particle
number and topology in a half-filled free fermion system. It is proposed that
the spin-projected particle numbers can distinguish the quantum spin Hall state
from other states, and can be used to establish a new topological index for the
system. Furthermore, we apply the new topological invariant to a disordered
system and show that a topological phase transition occurs when the disorder
strength is increased beyond a critical value. It is also shown that the
subsystem particle number fluctuation displays behavior very similar to that of
the entanglement entropy. This provides a lower-bound estimation for the
entanglement entropy, which can be utilized to obtain an estimate of the
entanglement entropy experimentally.Comment: 14 pages, 6 figure
Theory of Underdoped Cuprates
We develop a slave-boson theory for the t-J model at finite doping which
respects an SU(2) symmetry -- a symmetry previously known to be important at
half filling. The mean field phase diagram is found to be consistent with the
phases observed in the cuprate superconductors, which contains d-wave
superconductor, spin gap, strange metal, and Fermi liquid phases. The spin gap
phase is best understood as the staggered flux phase, which is nevertheless
translationally invariant for physical quantities. The electron spectral
function shows small Fermi pockets at low doping which continuously evolve into
the large Fermi surface at high doping concentrations.Comment: 4 pages, latex(revtex,epsf), 3 figure
EvIcon: Designing High-Usability Icon with Human-in-the-loop Exploration and IconCLIP
Interface icons are prevalent in various digital applications. Due to limited
time and budgets, many designers rely on informal evaluation, which often
results in poor usability icons. In this paper, we propose a unique
human-in-the-loop framework that allows our target users, i.e., novice and
professional UI designers, to improve the usability of interface icons
efficiently. We formulate several usability criteria into a perceptual
usability function and enable users to iteratively revise an icon set with an
interactive design tool, EvIcon. We take a large-scale pre-trained joint
image-text embedding (CLIP) and fine-tune it to embed icon visuals with icon
tags in the same embedding space (IconCLIP). During the revision process, our
design tool provides two types of instant perceptual usability feedback. First,
we provide perceptual usability feedback modeled by deep learning models
trained on IconCLIP embeddings and crowdsourced perceptual ratings. Second, we
use the embedding space of IconCLIP to assist users in improving icons' visual
distinguishability among icons within the user-prepared icon set. To provide
the perceptual prediction, we compiled IconCEPT10K, the first large-scale
dataset of perceptual usability ratings over interface icons, by
conducting a crowdsourcing study. We demonstrated that our framework could
benefit UI designers' interface icon revision process with a wide range of
professional experience. Moreover, the interface icons designed using our
framework achieved better semantic distance and familiarity, verified by an
additional online user study
Classification of Quantum Hall Universality Classes by $\ W_{1+\infty}\ $ symmetry
We show how two-dimensional incompressible quantum fluids and their
excitations can be viewed as edge conformal field theories,
thereby providing an algebraic characterization of incompressibility. The
Kac-Radul representation theory of the algebra leads then to
a purely algebraic complete classification of hierarchical quantum Hall states,
which encompasses all measured fractions. Spin-polarized electrons in
single-layer devices can only have Abelian anyon excitations.Comment: 11 pages, RevTeX 3.0, MPI-Ph/93-75 DFTT 65/9
Study of Decays with Polarization in Perturbative QCD Approach
The , decays are useful to determine the CKM
angle . Their polarization fractions are also interesting since
the polarization puzzle of the decay. We study these decays in
the perturbative QCD approach based on factorization.
After calculating of the non-factorizable and annihilation type
contributions, in addition to the conventional factorizable contributions, we
find that the contributions from the annihilation diagrams are crucial. They
give dominant contribution to the strong phases and suppress the longitudinal
polarizations. Our results agree with the current existing data. We also
predict a sizable direct CP asymmetries in , , and decays, which can be tested by the
oncoming measurements in the B factory experiments.Comment: 15 pages, latex, including 4 figure
Possible high temperature superconductivity in Ti-doped A-Sc-Fe-As-O (A= Ca, Sr) system
We report a systematic study on the effect of partial substitution of
Sc by Ti in SrScFeAsO, CaScFeAsO and
SrScFeAsO on their electrical properties. High
level of doping results in an increased carrier concentration and leads to the
appearance of superconductivity with the onset of T up to 45 K.Comment: 8 pages, 4 figures, 2 new figure
Advancing the additive manufacturing of PLA-ZnO nanocomposites by fused filament fabrication
Poly(lactic acid)-zinc oxide (PLA-ZnO) nanocomposites for fused filament fabrication have potential applications in the biomedical field as they combine the bio-compatibility of PLA with the antibacterial properties of ZnO. This work investigates the effects of masterbatch mixing strategy, ZnO concentration and ZnO surface treatment (silanisation) on the printability and the mechanical performance of the nanocomposites as a pre-requirement to the wider uptake of these materials. The results showed that the printability decreased as the filler loading increased. However, the surface treatment of the ZnO powder enhanced the matrix-filler interfacial interactions and reduced the thermal degradation of PLA. This ameliorated the printability and the tensile properties of the nanocomposites filled with up to 5 wt.% of ZnO. Moreover, despite the additional thermal treatment, melt-mixing prevented the degradative effect induced by the solvent used for solvent mixing. Future work will focus on assessing the antibacterial properties of the nanocomposite FFF parts
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