6,628 research outputs found
Paramagnetism in the kagome compounds (Zn,Mg,Cd)Cu(OH)Cl
Frustrated magnetism on the kagome lattice has been a fertile ground for rich
and fascinating physics, ranging from experimental evidence of a spin liquid to
theoretical predictions of exotic superconductivity. Among experimentally
realized spin- kagome magnets, herbertsmithite, kapellasite, and
haydeeite [(Zn,Mg)Cu(OH)Cl] are all well described by a
three-parameter Heisenberg model, but they exhibit distinctly different
physics. We address the problem using a pseudofermion functional
renormalization-group approach and analyze the low-energy physics in the
experimentally accessible parameter range. Our analysis places kapellasite and
haydeeite near the boundaries between magnetically ordered and disordered
phases, implying that slight modifications could dramatically affect their
magnetic properties. Inspired by this, we perform \textit{ab initio} density
functional theory calculations of (Zn,Mg,Cd)Cu (OH)Cl at
various pressures. Our results suggest that by varying pressure and composition
one can traverse a paramagnetic regime between different magnetically ordered
phases.Comment: Published version. Main paper (7 pages, 5 figures) and Supplemental
material (7 pages, 4 figures, 3 tables). Change in titl
A Novel Real-Time Non-invasive Hemoglobin Level Detection Using Video Images from Smartphone Camera
Hemoglobin level detection is necessary for evaluating health condition in the human. In the laboratory setting, it is detected by shining light through a small volume of blood and using a colorimetric electronic particle counting algorithm. This invasive process requires time, blood specimens, laboratory equipment, and facilities. There are also many studies on non-invasive hemoglobin level detection. Existing solutions are expensive and require buying additional devices. In this paper, we present a smartphone-based non-invasive hemoglobin detection method. It uses the video images collected from the fingertip of a person. We hypothesized that there is a significant relation between the fingertip mini-video images and the hemoglobin level by laboratory gold standard. We also discussed other non-invasive methods and compared with our model. Finally, we described our findings and discussed future works
Signatures of a gearwheel quantum spin liquid in a spin- pyrochlore molybdate Heisenberg antiferromagnet
We theoretically investigate the low-temperature phase of the recently
synthesized LuMoON material, an extraordinarily rare
realization of a three-dimensional pyrochlore Heisenberg
antiferromagnet in which Mo are the magnetic species. Despite a
Curie-Weiss temperature () of K, experiments have
found no signature of magnetic ordering spin freezing down to
K. Using density functional theory, we find that the compound
is well described by a Heisenberg model with exchange parameters up to third
nearest neighbors. The analysis of this model via the pseudofermion functional
renormalization group method reveals paramagnetic behavior down to a
temperature of at least , in agreement with the
experimental findings hinting at a possible three-dimensional quantum spin
liquid. The spin susceptibility profile in reciprocal space shows
momentum-dependent features forming a "gearwheel" pattern, characterizing what
may be viewed as a molten version of a chiral noncoplanar incommensurate spiral
order under the action of quantum fluctuations. Our calculated reciprocal space
susceptibility maps provide benchmarks for future neutron scattering
experiments on single crystals of LuMoON.Comment: Published version. Main paper (6 pages, 3 figures) + Supplemental
Material (4 pages, 3 figures, 1 table
Quantum Deconstruction of 5D SQCD
We deconstruct the fifth dimension of 5D SCQD with general numbers of colors
and flavors and general 5D Chern-Simons level; the latter is adjusted by adding
extra quarks to the 4D quiver. We use deconstruction as a non-stringy UV
completion of the quantum 5D theory; to prove its usefulness, we compute
quantum corrections to the SQCD_5 prepotential. We also explore the
moduli/parameter space of the deconstructed SQCD_5 and show that for |K_CS| <
N_F/2 it continues to negative values of 1/(g_5)^2. In many cases there are
flop transitions connecting SQCD_5 to exotic 5D theories such as E0, and we
present several examples of such transitions. We compare deconstruction to
brane-web engineering of the same SQCD_5 and show that the phase diagram is the
same in both cases; indeed, the two UV completions are in the same universality
class, although they are not dual to each other. Hence, the phase structure of
an SQCD_5 (and presumably any other 5D gauge theory) is inherently
five-dimensional and does not depends on a UV completion.Comment: LaTeX+PStricks, 108 pages, 41 colored figures. Please print in colo
Quiver Theories from D6-branes via Mirror Symmetry
We study N=1 four dimensional quiver theories arising on the worldvolume of
D3-branes at del Pezzo singularities of Calabi-Yau threefolds. We argue that
under local mirror symmetry D3-branes become D6-branes wrapped on a three torus
in the mirror manifold. The type IIB (p,q) 5-brane web description of the local
del Pezzo, being closely related to the geometry of its mirror manifold,
encodes the geometry of 3-cycles and is used to obtain gauge groups, quiver
diagrams and the charges of the fractional branes.Comment: 30 pages, citations adde
Symmetries in M-theory: Monsters, Inc
We will review the algebras which have been conjectured as symmetries in
M-theory. The Borcherds algebras, which are the most general Lie algebras under
control, seem natural candidates.Comment: 6 pages, talk given by PHL at Cargese 200
Fuzzy rule based profiling approach for enterprise information seeking and retrieval
With the exponential growth of information available on the Internet and various organisational intranets there is a need for profile based information seeking and retrieval (IS&R) systems. These systems should be able to support users with their context-aware information needs. This paper presents a new approach for enterprise IS&R systems using fuzzy logic to develop task, user and document profiles to model user information seeking behaviour. Relevance feedback was captured from real users engaged in IS&R tasks. The feedback was used to develop a linear regression model for predicting document relevancy based on implicit relevance indicators. Fuzzy relevance profiles were created using Term Frequency and Inverse Document Frequency (TF/IDF) analysis for the successful user queries. Fuzzy rule based summarisation was used to integrate the three profiles into a unified index reflecting the semantic weight of the query terms related to the task, user and document. The unified index was used to select the most relevant documents and experts related to the query topic. The overall performance of the system was evaluated based on standard precision and recall metrics which show significant improvements in retrieving relevant documents in response to user queries
Challenges in Developing Applications for Aging Populations
Elderly individuals can greatly benefit from the use of computer applications, which can assist in monitoring health conditions, staying in contact with friends and family, and even learning new things. However, developing accessible applications for an elderly user can be a daunting task for developers. Since the advent of the personal computer, the benefits and challenges of developing applications for older adults have been a hot topic of discussion. In this chapter, the authors discuss the various challenges developers who wish to create applications for the elderly computer user face, including age-related impairments, generational differences in computer use, and the hardware constraints mobile devices pose for application developers. Although these challenges are concerning, each can be overcome after being properly identified
Matrix Models, Geometric Engineering and Elliptic Genera
We compute the prepotential of N=2 supersymmetric gauge theories in four
dimensions obtained by toroidal compactifications of gauge theories from 6
dimensions, as a function of Kahler and complex moduli of T^2. We use three
different methods to obtain this: matrix models, geometric engineering and
instanton calculus. Matrix model approach involves summing up planar diagrams
of an associated gauge theory on T^2. Geometric engineering involves
considering F-theory on elliptic threefolds, and using topological vertex to
sum up worldsheet instantons. Instanton calculus involves computation of
elliptic genera of instanton moduli spaces on R^4. We study the
compactifications of N=2* theory in detail and establish equivalence of all
these three approaches in this case. As a byproduct we geometrically engineer
theories with massive adjoint fields. As one application, we show that the
moduli space of mass deformed M5-branes wrapped on T^2 combines the Kahler and
complex moduli of T^2 and the mass parameter into the period matrix of a genus
2 curve.Comment: 90 pages, Late
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