1,230 research outputs found
Triangle anomaly in Weyl semi-metals
Weyl semimetals possess massless chiral quasi-particles, and are thus
affected by the triangle anomalies. We discuss the features of the chiral
magnetic and chiral vortical effects specific to Weyl semimetals, and then
propose three novel phenomena caused by the triangle anomalies in this
material: 1) anomaly cooling; 2) charge transport by soliton waves as described
by the Burgers' equation, and 3) the shift of the BKT phase transition of
superfluid vortices coupled to Weyl fermions. In addition, we establish the
conditions under which the chiral magnetic current exists in real materials.Comment: v3. Improved figures, minor changes in the text, 24 pages, 3 figure
Chiral Modulations in Curved Space I: Formalism
The goal of this paper is to present a formalism that allows to handle
four-fermion effective theories at finite temperature and density in curved
space. The formalism is based on the use of the effective action and zeta
function regularization, supports the inclusion of inhomogeneous and
anisotropic phases. One of the key points of the method is the use of a
non-perturbative ansatz for the heat-kernel that returns the effective action
in partially resummed form, providing a way to go beyond the approximations
based on the Ginzburg-Landau expansion for the partition function. The
effective action for the case of ultra-static Riemannian spacetimes with
compact spatial section is discussed in general and a series representation,
valid when the chemical potential satisfies a certain constraint, is derived.
To see the formalism at work, we consider the case of static Einstein spaces at
zero chemical potential. Although in this case we expect inhomogeneous phases
to occur only as meta-stable states, the problem is complex enough and allows
to illustrate how to implement numerical studies of inhomogeneous phases in
curved space. Finally, we extend the formalism to include arbitrary chemical
potentials and obtain the analytical continuation of the effective action in
curved space.Comment: 22 pages, 3 figures; version to appear in JHE
A note on a gauge-gravity relation and functional determinants
We present a refinement of a recently found gauge-gravity relation between
one-loop effective actions: on the gauge side, for a massive charged scalar in
2d dimensions in a constant maximally symmetric electromagnetic field; on the
gravity side, for a massive spinor in d-dimensional (Euclidean) anti-de Sitter
space. The inclusion of the dimensionally regularized volume of AdS leads to
complete mapping within dimensional regularization. In even-dimensional AdS, we
get a small correction to the original proposal; whereas in odd-dimensional
AdS, the mapping is totally new and subtle, with the `holographic trace
anomaly' playing a crucial role.Comment: 6 pages, io
Group Chase and Escape
We describe here a new concept of one group chasing another, called "group
chase and escape", by presenting a simple model. We will show that even a
simple model can demonstrate rather rich and complex behavior. In particular,
there are cases in which an optimal number of chasers exists for a given number
of escapees (or targets) to minimize the cost of catching all targets. We have
also found an indication of self-organized spatial structures formed by both
groups.Comment: 13 pages, 12 figures, accepted and to appear in New Journal of
Physic
Pengaruh Penyuplemenan Spirulina Dalam Pakan Terhadap Hematologis Ikan Nilem (Osteochilus Hasselti C.v.) Effect of Supplemented Spirulina in Diet on Nilem Fish (Osteochilus Hasselti C.v.) Haematologys
The aim of this research was to know the effect of supplemented Spirulina in diet on nilem fish haematologys and to obtain the best dose. Pre-treated fishes were acclimated to the laboratory environment for 10 days then allocated randomly into 4 treatment groups. Each group consisted of three aquaria containing 100 L of water equipped with recirculatory system, 12 fishes were allocated into each
aquarium. Fish in group A served as control given pellet without Spirulina. Fishes in groups B, C, and D were given pellet supplemented with 2, 4, and 6 g.kg-1 Spirulina, respectively, given daily at 07.30 and 16.00 at 5% of body weight. The results showed that haematologys profile on the nilem fish was affected by Spirulina. This was indicated by increasing erythrocyte counts, total leucocyte, and haemoglobin level as well as haematocrite value. Supplement with 4 g.kg-1 Spirulina was the best dose
A heterobivalent ligand inhibits mast cell degranulation via selective inhibition of allergen-IgE interactions in vivo
Current treatments for allergies include epinephrine and antihistamines, which treat the symptoms after an allergic response has taken place; steroids, which result in local and systemic immune suppression; and IgE-depleting therapies, which can be used only for a narrow range of clinical IgE titers. The limitations of current treatments motivated the design of a heterobivalent inhibitor (HBI) of IgE-mediated allergic responses that selectively inhibits allergen-IgE interactions, thereby preventing IgE clustering and mast cell degranulation. The HBI was designed to simultaneously target the allergen binding site and the adjacent conserved nucleotide binding site (NBS) found on the Fab of IgE Abs. The bivalent targeting was accomplished by linking a hapten to an NBS ligand with an ethylene glycol linker. The hapten moiety of HBI enables selective targeting of a specific IgE, whereas the NBS ligand enhances avidity for the IgE. Simultaneous bivalent binding to both sites provided HBI with 120-fold enhancement in avidity for the target IgE compared with the monovalent hapten. The increased avidity for IgE made HBI a potent inhibitor of mast cell degranulation in the rat basophilic leukemia mast cell model, in the passive cutaneous anaphylaxis mouse model of allergy, and in mice sensitized to the model allergen. In addition, HBI did not have any observable systemic toxic effects even at elevated doses. Taken together, these results establish the HBI design as a broadly applicable platform with therapeutic potential for the targeted and selective inhibition of IgE-mediated allergic responses, including food, environmental, and drug allergies
Determinant and Weyl anomaly of Dirac operator: a holographic derivation
We present a holographic formula relating functional determinants: the
fermion determinant in the one-loop effective action of bulk spinors in an
asymptotically locally AdS background, and the determinant of the two-point
function of the dual operator at the conformal boundary. The formula originates
from AdS/CFT heuristics that map a quantum contribution in the bulk partition
function to a subleading large-N contribution in the boundary partition
function. We use this holographic picture to address questions in spectral
theory and conformal geometry. As an instance, we compute the type-A Weyl
anomaly and the determinant of the iterated Dirac operator on round spheres,
express the latter in terms of Barnes' multiple gamma function and gain insight
into a conjecture by B\"ar and Schopka.Comment: 11 pages; new comments and references added, typos correcte
Holographic two dimensional QCD and Chern-Simons term
We present a holographic realization of large Nc massless QCD in two
dimensions using a D2/D8 brane construction. The flavor axial anomaly is dual
to a three dimensional Chern-Simons term which turns out to be of leading
order, and it affects the meson spectrum and holographic renormalization in
crucial ways. The massless flavor bosons that exist in the spectrum are found
to decouple from the heavier mesons, in agreement with the general lore of
non-Abelian bosonization. We also show that an external dynamical photon
acquires a mass through the three dimensional Chern-Simons term as expected
from the Schwinger mechanism. Massless two dimensional QCD at large Nc exhibits
anti-vector-meson dominance due to the axial anomaly.Comment: 22 page
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