1,415 research outputs found
Notes on Superconformal Chern-Simons-Matter Theories
The three dimensional N=2 supersymmetric Chern-Simons theory coupled to
matter fields, possibly deformed by a superpotential, give rise to a large
class of exactly conformal theories with Lagrangian descriptions. These
theories can be arbitrarily weakly coupled, and hence can be studied
perturbatively. We study the theories in the large N limit, and compute the
two-loop anomalous dimension of certain long operators. Our result suggests
that various N=2 U(N) Chern-Simons theories coupled to suitable matter fields
are dual to open or closed string theories in AdS4, which are not yet
constructed.Comment: 47 pages, 20 figure
Implementation of a two-qubit controlled-U gate based on unconventional geometric phase with a constant gating time
We propose an alternative scheme to implement a two-qubits Controlled-U gate
in the hybrid system atom- (coupled cavities array). Our scheme results in
a constant gating time and, with an adjustable qubit-bus coupling
(atom-resonator), one can specify a particular transformation on the target
qubit. We believe that this proposal may open promising perspectives for
networking quantum information processors and implementing distributed and
scalable quantum computation.Comment: 4 pages, 1 figure, APS format, an extended version is in progress
with some improvement
The rare top quark decays in the topcolor-assisted technicolor model
We consider the rare top quark decays in the framework of topcolor-assisted
technicolor (TC2) model. We find that the contributions of top-pions and
top-Higgs predicted by the TC2 model can enhance the SM branching ratios by as
much as 6-9 orders of magnitude. i.e., in the most case, the orders of
magnitude of branching ratios are , , . With the reasonable values of the
parameters in TC2 model, such rare top quark decays may be testable in the
future experiments. So, rare top quark decays provide us a unique way to test
TC2 model.Comment: 14 pages, 4 figure
Examples of M5-Brane Elliptic Genera
We determine the modified elliptic genus of an M5-brane wrapped on various
one modulus Calabi-Yau spaces, using modular invariance together with some
known Gopakumar-Vafa invariants of small degrees. As a bonus, we find
nontrivial relations among Gopakumar-Vafa invariants of different degrees and
genera from modular invariance.Comment: 13 page
Probability Distribution Function of the Order Parameter: Mixing Fields and Universality
We briefly review the use of the order parameter probability distribution
function as a useful tool to obtain the critical properties of statistical
mechanical models using computer Monte Carlo simulations. Some simple discrete
spin magnetic systems on a lattice, such as Ising, general spin- Blume-Capel
and Baxter-Wu, -state Potts, among other models, will be considered as
examples. The importance and the necessity of the role of mixing fields in
asymmetric magnetic models will be discussed in more detail, as well as the
corresponding distributions of the extensive conjugate variables.Comment: 14 pages, 13 figures, accepted for publication (Computer Physics
Communications
An Afferent Vagal Nerve Pathway Links Hepatic PPARα Activation to Glucocorticoid-Induced Insulin Resistance and Hypertension
SummaryGlucocorticoid excess causes insulin resistance and hypertension. Hepatic expression of PPARα (Ppara) is required for glucocorticoid-induced insulin resistance. Here we demonstrate that afferent fibers of the vagus nerve interface with hepatic Ppara expression to disrupt blood pressure and glucose homeostasis in response to glucocorticoids. Selective hepatic vagotomy decreased hyperglycemia, hyperinsulinemia, hepatic insulin resistance, Ppara expression, and phosphoenolpyruvate carboxykinase (PEPCK) enzyme activity in dexamethasone-treated Ppara+/+ mice. Selective vagotomy also decreased blood pressure, adrenergic tone, renin activity, and urinary sodium retention in these mice. Hepatic reconstitution of Ppara in nondiabetic, normotensive dexamethasone-treated PPARα null mice increased glucose, insulin, hepatic PEPCK enzyme activity, blood pressure, and renin activity in sham-operated animals but not hepatic-vagotomized animals. Disruption of vagal afferent fibers by chemical or surgical means prevented glucocorticoid-induced metabolic derangements. We conclude that a dynamic interaction between hepatic Ppara expression and a vagal afferent pathway is essential for glucocorticoid induction of diabetes and hypertension
Solidification of Al alloys under electromagnetic pulses and characterization of the 3D microstructures under synchrotron x-ray tomography
A novel programmable electromagnetic pulse device was developed and used to study the solidification of Al-15 pct Cu and Al-35 pct Cu alloys. The pulsed magnetic fluxes and Lorentz forces generated inside the solidifying melts were simulated using finite element methods, and their effects on the solidification microstructures were characterized using electron microscopy and synchrotron X-ray tomography. Using a discharging voltage of 120 V, a pulsed magnetic field with the peak Lorentz force of ~1.6 N was generated inside the solidifying Al-Cu melts which were showed sufficiently enough to disrupt the growth of the primary Al dendrites and the Al2Cu intermetallic phases. The microstructures exhibit a strong correlation to the characteristics of the applied pulse, forming a periodical pattern that resonates the frequency of the applied electromagnetic field
Olympic legacy and cultural tourism: Exploring the facets of Athens' Olympic heritage
This study examines the effects of the Olympic Games on Athensâ cultural tourism and the cityâs potential to leverage the Olympic legacy in synergy with its rich heritage in order to enhance its tourism product during the post-Games period. In doing so, a qualitative and interpretive approach was employed. This includes a literature review on Athensâ 2004 Olympics to identify the sport facilities and regeneration projects, which constitute the Olympic legacy and heritage. Based on that, an empirical analysis was undertaken, by collecting official documents about the 2004 Olympics, and conducting five semi-structured interviews with tourism/administrative officials. The findings indicate that the Olympiad contributed significantly to Athensâ built and human heritage, revealing the dimensions of new venues/facilities, infrastructure, transportation and aesthetic image of the city, and human capital enhancement. Hence, the Games affected to the multifaceted representation and reconstruction of the cityâs identity and cultural heritage. However, the potential afforded from the post-Olympic Athens remains unrealised due to lack of strategic planning/management. The study concludes that there is a need to develop cross-leveraging synergies between the Olympic legacy and cultural tourism for the host city. Finally, a strategic planning framework for leveraging post-Games Olympic tourism is suggested in order to maximise the benefits of Olympic legacy and heritage in a host cityâs tourism development
Monte Carlo integration in Glauber model analysis of reactions of halo nuclei
Reaction and elastic differential cross sections are calculated for light
nuclei in the framework of the Glauber theory. The optical phase-shift function
is evaluated by Monte Carlo integration. This enables us to use the most
accurate wave functions and calculate the phase-shift functions without
approximation. Examples of proton nucleus (e.g. p-He, p-Li) and
nucleus-nucleus (e.g. HeC) scatterings illustrate the effectiveness
of the method. This approach gives us a possibility of a more stringent
analysis of the high-energy reactions of halo nuclei.Comment: 20 pages, 8 figure
Spin Chains in N=6 Superconformal Chern-Simons-Matter Theory
In this note we study spin chain operators in the N=6 Chern-Simons-matter
theory recently proposed by Aharony, Bergman, Jafferis and Maldacena to be dual
to type IIA string theory in AdS4xCP3. We study the two-loop dilatation
operator in the gauge theory, and compare to the Penrose limit on the string
theory side.Comment: 19 pages, 15 figures; minor corrections, references adde
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