Chiral Condensate in Holographic QCD with Baryon Density

We consider the chiral condensate in the baryonic dense medium using the generalized Sakai-Sugimoto model. It is defined as the vacuum expectation value of open Wilson line that is proposed to be calculated by use of the area of world-sheet instanton. We evaluate it in confined as well as deconfined phase. In both phases, the chiral condensate has a minimum as a function of baryon density. In the deconfined phase, taking into account the chiral symmetry restoration, we classify the behavior of chiral condensate into three types. One can set the parameter of the theory such that the results, in low but sufficiently higher density, is in agreement with the expectation from QCD.Comment: 23 pages, 8 figure

Lepton-nucleus scattering in the impulse approximation regime

We discuss theoretical calculations of electron- and neutrino-nucleus scattering, carried out using realistic nuclear spectral functions and including the effect of final state interactions. Comparison between electron scattering data and the calculated inclusive cross sections off oxygen shows that the Fermi gas model fails to provide a satisfactory description of the measured cross sections, and inclusion of nuclear dynamics is needed. The role of Pauli blocking in charged-current neutrino induced reactions at low $Q^2$ is also analyzed.Comment: To be published in the Proceedings of NUFACT05 (Nucl. Phys. B, Proceedings Supplements

Deciding Full Branching Time Logic by Program Transformation

We present a method based on logic program transformation, for verifying Computation Tree Logic (CTL*) properties of finite state reactive systems. The finite state systems and the CTL* properties we want to verify, are encoded as logic programs on infinite lists. Our verification method consists of two steps. In the first step we transform the logic program that encodes the given system and the given property, into a monadic ω -program, that is, a stratified program defining nullary or unary predicates on infinite lists. This transformation is performed by applying unfold/fold rules that preserve the perfect model of the initial program. In the second step we verify the property of interest by using a proof method for monadic ω-program

Winding effects on brane/anti-brane pairs

We study a brane/anti-brane configuration which is separated along a compact direction by constructing a tachyon effective action which takes into account transverse scalars. Such an action is relevant in the study of HQCD model of Sakai and Sugimoto of chiral symmetry breaking, where the size of the compact circle sets the confinement scale. Our approach is motivated by string theory orbifold constructions and gives a route to model inhomogeneous tachyon decay. We illustrate the techniques involved with a relatively simple example of a harmonic oscillator on a circle. We will then repeat the analysis for the Sakai-Sugimoto model and show that by integrating out the winding modes will provide us with a renormalized action with a lower energy than that of truncating to zero winding sector.Comment: 21 pages, 3 figures. v3: discussion and references added, published versio

Optical Potential for the p-Shell Heavy Ion Scattering

開始ページ、終了ページ: 冊子体のページ付

Peristaltic Transport of a Couple Stress Fluid: Some Applications to Hemodynamics

The present paper deals with a theoretical investigation of the peristaltic transport of a couple stress fluid in a porous channel. The study is motivated towards the physiological flow of blood in the micro-circulatory system, by taking account of the particle size effect. The velocity, pressure gradient, stream function and frictional force of blood are investigated, when the Reynolds number is small and the wavelength is large, by using appropriate analytical and numerical methods. Effects of different physical parameters reflecting porosity, Darcy number, couple stress parameter as well as amplitude ratio on velocity profiles, pumping action and frictional force, streamlines pattern and trapping of blood are studied with particular emphasis. The computational results are presented in graphical form. The results are found to be in good agreement with those of Shapiro et. al \cite{r25} that was carried out for a non-porous channel in the absence of couple stress effect. The present study puts forward an important observation that for peristaltic transport of a couple stress fluid during free pumping when the couple stress effect of the fluid/Darcy permeability of the medium, flow reversal can be controlled to a considerable extent. Also by reducing the permeability it is possible to avoid the occurrence of trapping phenomenon

Two Phase Model Analysis for the Stokes Flow past a Sphere Attached to the Circular Tube Wall

微小血管内では,血管壁近傍に赤血球がほとんど通らない領域が見られ,血漿層と呼ばれている.本研究では,細静脈壁に接着している白血球に血流が及ぼす剪断応力に対して,血漿層が与える影響をモデル解析によって調べた.血管を直円管,白血球を剛体球とし,血液の流れを血漿層と,赤血球が多数通過する中心層とからなる二層流と仮定して白血球周りの流れ場を数値的に解析した.その結果として,血漿層の効果によって白血球に作用する剪断応力は増加することが示された.\nThe blood flow past a leukocyte adhered to the microvessel wall is analyzed by a numerical simulation, taking the presence of a cell-free layer into account. The adherent leukocyte is modeled as a sphere attached to the wall of a circular cylindrical tube. The blood flow is modeled as a two-phase flow, consisting of a plasma flow in a cell-free layer adjacent to the vessel wall and the cell-rich flow in the central region of the vessel. It is assumed that each fluid in both regions is Newtonian with a uniform viscosity and that the viscosity of the cell-free layer is smaller than that of the central core. The interface between the two regions is assumed to be parallel to the streamlines. Numerical simulations by a finite element method have demonstrated that there are two different cases of the flow pattern around a sphere: one is a case where the whole sphere is embedded in the cell-free layer, and the other is a case where the sphere is covered by the central core. In both cases, the maximum magnitudes of the shear stress acting on the leukocyte are higher than those in the absence of the cell-free layer

Tunable gigahertz dynamics of low-temperature skyrmion lattice in a chiral magnet

Recently, it has been shown that the chiral magnetic insulator Cu2OSeO3hosts skyrmions in two separated pockets in temperature and magnetic field phase space. It has also been shown that the predominant stabilization mechanism for the low-temperature skyrmion (LTS) phase is via the crystalline anisotropy, opposed to temperature fluctuations that stabilize the well-established high-temperature skyrmion (HTS) phase. Here, we report on a detailed study of LTS generation by field cycling, probed by GHz spin dynamics in Cu2OSeO3. LTSs are populated via a field cycling protocol with the static magnetic field applied parallel to the ⟨100⟩ crystalline direction of plate and cuboid-shaped bulk crystals. By analyzing temperature-dependent broadband spectroscopy data, clear evidence of LTS excitations with clockwise (CW), counterclockwise (CCW), and breathing mode (BR) character at temperatures belowT= 40 K are shown. We find that the mode intensities can be tuned with the number of field-cycles below the saturation field. By tracking the resonance frequencies, we are able to map out the field-cycle-generated LTS phase diagram, from which we conclude that the LTS phase is distinctly separated from the high-temperature counterpart. We also study the mode hybridization between the dark CW and the BR modes as a function of temperature. By using two Cu2OSeO3crystals with different shapes and therefore different demagnetization factors, together with numerical calculations, we unambiguously show that the magnetocrystalline anisotropy plays a central role for the mode hybridization

Aspirin-Trigge red-Resolvin D1 reduces mucosal inflammation and promotes resolution in a murine model of acute lung injury

Acute Lung Injury (ALI) is a severe illness with excess mortality and no specific therapy. Protective actions were recently uncovered for docosahexaenoic acid -derived mediators, including D-series resolvins. Here, we used a murine self-limited model of hydrochloric acid-induced ALI to determine the effects of aspirin-triggered resolvin D1 (AT-RvD1) on mucosal injury. RvD1 and its receptor ALX/FPR2 were identified in murine lung after ALI. AT-RvD1 (~0.5 – 5 μg/kg) decreased peak inflammation, including bronchoalveolar lavage fluid (BALF) neutrophils by ~75%. Animals treated with AT-RvD1 had improved epithelial and endothelial barrier integrity and decreased airway resistance concomitant with increased BALF epinephrine levels. AT-RvD1 inhibited neutrophil-platelet heterotypic interactions by down-regulating both P-selectin and its ligand CD24. AT-RvD1 also significantly decreased levels of BALF pro-inflammatory cytokines, including IL-1β, IL-6, KC and TNF-α, and decreased NF-κB phosphorylated p65 nuclear translocation. Together, these findings indicate that AT-RvD1 displays potent mucosal protection and promotes catabasis after ALI