Analytic Methods in Open String Field Theory

Yuji Okawa — 2012-12-10T09:00:00+09:00

Authors: Yuji Okawa
We review the basics of recent developmentsof analytic methods in open string field theory.We in particular explain Schnabl's analytic solutionfor tachyon condensation in detail,assuming only the basic knowledge on conformal field theory.

Subbarrier Fusion Reactions and Many-Particle Quantum Tunneling

Kouichi Hagino and Noboru Takigawa — 2012-12-10T09:00:00+09:00

Authors: Kouichi Hagino and Noboru Takigawa
Low-energy heavy-ion fusion reactions are governed by quantum tunneling through the Coulomb barrier formed by the strong cancellation of the repulsive Coulomb force with the attractive nuclear interaction between the colliding nuclei. Extensive experimental as well as theoretical studies have revealed that fusion reactions are strongly influenced by couplings of the relative motion of the colliding nuclei to several nuclear intrinsic motions. Heavy-ion subbarrier fusion reactions thus provide a good opportunity to address the general problem of quantum tunneling in the presence of couplings, which has been a popular subject in recent decades in many branches of physics and chemistry. Here, we review theoretical aspects of heavy-ion subbarrier fusion reactions from the viewpoint of quantum tunneling in systems with many degrees of freedom. Particular emphases are put on the coupled-channels approach to fusion reactions and the barrier distribution representation for multichannel penetrability. We also discuss an application ofthe barrier distribution method to elucidate the mechanism of the dissociative adsorption of H_{2} molecules in surface science.

Quaternionic Variational Formalism for General Relativity in Riemann and Riemann-Cartan Space-Times

Katsusada Morita — 2012-12-10T09:00:00+09:00

Authors: Katsusada Morita
It is shown that there exists a 2-dimensional matrixrepresentation of complex quaternions over real quaternions,which allows to define Pauli matrix in 4 dimensions over thequaternionic field and leads to the quaternionic spinor grouppreviously proposed. It is also attempted to apply complexquaternions to general relativity at the level of the variationalformalism. Linear gravitational Lagrangian in Riemann-Cartanspace-time U_{4} is derived using quaternion caluculus;namely scalar curvature in U_{4} is put into a quaternionicform. Consequently, Einstein-Hilbert Lagrangian in Riemannspace R_{4} is also defined over quaternions, as first shownby Sachs. The matter fields coupled to gravity are assumedto be the scalar and the Dirac fields. The quaternionicvariational formalism corresponds to the first-order formalismbut with a limited pattern of allowed fields such that thequaternionic fields carry only coordinate tensor indices butno local Lorentz indices which are contracted with thatpossessed by the basis of complex quaternions. In particular,both the quaternionic vierbein field and Lorentz gauge field(corresponding to the spin connection) are regarded ascoordinate vectors which are independently varied, obtainingEinstein and Cartan equations, respectively. It is incidentallyshown that the consistent condition of Einstein equation inU_{4} is proved via the variational formalism and theanti-symmetric part of Einstein equation together withCartan equation in U_{4} leads to an identity which expressesthe anti-symmetric part of the enegy-momentum tensor by meansof the covariant divergence of the spin angular momentum tensor,both of Dirac field. We also present pedagogical proofs ofBianchi and Bach-Lanczos identities in U_{4} using thequaternionic formalism.

Synchronization Thresholds of Coupled Self-Excited Nonidentical Pendula Suspended on the Vertically Displacing Beam

2012-12-10T09:00:00+09:00

Authors: Marcin Kapitaniak, Piotr Brzeski, Krzysztof Czolczynski, Przemysław Perlikowski, Andrzej Stefanski and Tomasz Kapitaniak
The synchronization of a number of self-excited nonidentical pendula (with the same masses and different lengths) hanging on the same beam which can move vertically has been investigated. We identify different synchronous configurations and investigate their stability. An approximate analytical analysis of the energy balance allows to derive the synchronization conditions, phase difference between the pendula and explains the observed types of synchronizations. We give evidence of two thresholds (in a number of pendula and differences in lengths) after which the synchronization is not observed. It has been shown that for more than three pendula with sufficiently large differences in the lengths the synchronization is not observed and the pendula perform quasi-periodic oscillations. Our results are robust as they exist for the wide set of system parameters.

Confinement and Dynamical Symmetry Breaking in Non-SUSY Gauge Theory from S-Duality in String Theory

Shigeki Sugimoto — 2012-12-10T09:00:00+09:00

Authors: Shigeki Sugimoto
We discuss an attempt to understand confinement and dynamical symmetrybreaking in a 4-dimensional non-supersymmetric gauge theory usingS-duality in type IIB string theory. The electric theory is a USp(2n)gauge theory and its magnetic dual is argued to be an SO(2n) orSO(2n-1) gauge theory. These theories are obtained as the low-energyeffective theory of O3-\overlineD3 systems in type IIB string theory, whichare related by S-duality. Confinement and dynamical symmetrybreaking in the USp(2n) gauge theory are caused by thecondensation of scalar fields in the magnetic dual description, which isconsistent with the scenario of the dual Meissner mechanism for the confinement.

Analytical Calculation on Critical Magnetic Field in Holographic Superconductors with Backreaction

Xian-Hui Ge and Hong-Qiang Leng — 2012-12-10T09:00:00+09:00

Authors: Xian-Hui Ge and Hong-Qiang Leng
We investigate the effect of spacetime backreaction on the upper critical magnetic field for s-wave holographic superconductors by using the matching method.The backreaction of the constant external magnetic field and the electric fieldto the background geometry leads to a dyonic black hole solution.The magnetic fields as well as the electric fields acting as gravitationalsources tend to depress the critical temperature of the superconductor.We derive the analytical expression for the upper critical magnetic field up toO(κ^{2}) order and find that backreaction makes the uppercritical magnetic field stronger. The result is consistent with the previousnumerical and analytical results.

Suppressing Proton Decay by Cancellation in S_{4} Flavor Symmetric Extra U(1) Model

Yasuhiro Daikoku and Hiroshi Okada — 2012-12-10T09:00:00+09:00

Authors: Yasuhiro Daikoku and Hiroshi Okada
We consider proton stability based on E_{6} inspired extra U(1) model with S_{4} flavor symmetry.In this model, a long life time of proton is realized by the flavor symmetry.One of the interesting effects of flavor symmetry is thatthe proton decay widths of p →µ^{+} X are suppressed by cancellation. This suppression mechanism is important in the case thatYukawa coupling constants are hierarchical.Our model predicts p →e^{+}K^{0} has larger decay width than that ofp →µ^{+}K^{0}.

Mass Insertion Formula for Chargino Contribution to ΔB = 1 Wilson Coefficients and Its Application to CP Asymmetries of B →Kπ

Motoi Endo and Takahiro Yoshinaga — 2012-12-10T09:00:00+09:00

Authors: Motoi Endo and Takahiro Yoshinaga
The comprehensive mass insertion formula of the b →s \barq q transitionswas provided for the chargino contributions. The method clarifies physicsbehind the calculations of the supersymmetric contributions to FCNCs. Theresult was applied to the analysis of the difference of the CP asymmetries ofthe B →Kπ decays. It is shown that the supersymmetry is not responsiblefor the discrepancy.

Toward an Understanding of Short Distance Repulsions among Baryons in QCD

Sinya Aoki, Janos Balog and Peter Weisz — 2012-12-10T09:00:00+09:00

Authors: Sinya Aoki, Janos Balog and Peter Weisz
We report on our recent attempts to determine the short distance behaviors of general 2-baryon and 3-baryon forces, which are defined from the Nambu-Bethe-Salpeter (NBS) wave function,by using the operator product expansion and a renormalization group analysis in QCD.We have found that the repulsion at short distance increases as the number of valence quarks increases or when the number of different flavors involved decreases. This global tendency suggests a Pauli suppression principle among quark fields at work.

Level Spacings of Parametric Chiral Random Matrices and Two-Color QCD with Twisted Boundary Condition

Shinsuke M. Nishigaki — 2012-12-10T09:00:00+09:00

Authors: Shinsuke M. Nishigaki
We evaluate the level spacing and smallest eigenvalue distributionsof chiral random matrix ensembles transiting from symplectic or orthogonal to unitary symmetry classes with a crossover parameter ρ.As expected from the effective σ model description,these results can be fitted perfectly to the fundamental or adjoint staggered Dirac spectrum of SU(2) quenched lattice gauge theory under the imaginary chemical potential (twisting) µ.The linear dependence of the parameter ρ on µ determines the pion decay constant F as its proportionality constant.

Extrinsic Spin Hall Effect Due to Transition-Metal Impurities

Takuro Tanaka and Hiroshi Kontani — 2012-11-19T09:00:00+09:00

Authors: Takuro Tanaka and Hiroshi Kontani
We investigate the extrinsic spin Hall effect in the electron gas model due to transition-metal impurities based on thesingle-impurity Anderson model with orbital degrees of freedom.Both the skew scattering and side jump mechanisms are analyzed in a unified way, and the significant role of orbital degrees of freedom are clarified. The obtained spin Hall conductivities are in proportion to the spin-orbit polarization at the Fermi level <l ·s >_{µ} as is the case with the intrinsic spin Hall effect: skew scattering term σ_{ SH}^{ ss} ∝<l ·s >_{µ} δ_{1} σ_{xx}, and side jump term σ_{ SH}^{ sj} ∝<l ·s >_{µ}, where δ_{1} is the phase shift for p (l = 1) partial wave. Furthermore, the present study indicates the existence of a nontrivial close relationship between the intrinsic term σ_{ SH}^{ int} and the extrinsic side jump term σ_{ SH}^{ sj}.

Spinless Basis for Spin-Singlet FQH States

Taro Kimura — 2012-11-19T09:00:00+09:00

Authors: Taro Kimura
We investigate an alternative description of the SU(M)-singlet FQHstate by using the spinless basis.The SU(M)-singlet Halperin state is obtained via the q-deformationof the Laughlin state and its root of unity limit, by applying theYangian Gelfand-Zetlin basis for the spin Calogero-Sutherland model.The squeezing rule for the SU(M) state is also investigated in terms of thespinless basis.

New Period-Doubling and Equiperiod Bifurcations of the Reversible Area-Preserving Map

Yoshihiro Yamaguchi and Kiyotaka Tanikawa — 2012-11-19T09:00:00+09:00

Authors: Yoshihiro Yamaguchi and Kiyotaka Tanikawa
Two types of period-doubling and equiperiod bifurcations of the reversible area-preserving map are studied. Ordinary period-doubling bifurcation means that the eigenvalue of the mother elliptic periodic orbit (u) is -1, u becomes a saddle periodic orbit with reflection, and an elliptic daughterperiodic orbit (v) appears, where the period of v is twice that of u. The other period-doubling bifurcation named the reverseperiod-doubling bifurcation means that the eigenvalue of the mother saddleperiodic orbit with reflection (u') is -1, u' becomes an elliptic orbit, and a daughter periodicorbit (v') appears, where the period of v' is twice that of u'. The daughter periodic orbit is a saddle with reflection. We prove that both the daughters v and v' exist in the reversible Smale horseshoe. The forcing relation of the ordinary and reverse period-bifurcations is obtained.Similarly, the ordinary equiperiod and reverse equiperiodbifurcations are also discussed.

On Static Charged Black Holes in Type IIA on a Nearly-Kähler Coset

Tetsuji Kimura — 2012-11-19T09:00:00+09:00

Authors: Tetsuji Kimura
We study static, spherically symmetric black hole solutions in four-dimensional N = 2 gauged supergravity with one vector multiplet and one hyper-tensor multiplet.This is derived from massive type IIA theory compactified on the nearly-Kähler coset space G_{2}/SU(3).It is well known that the Romans' mass parameter yields the Stückelberg-type deformation of the gauge field strengths in the four-dimensional system.This deformation requires that all the (covariant) derivatives of the scalar fields must vanish and the two-form field is closed.It turns out that charged solutions are forbidden. This implies that only AdS vacua or Schwarzschild-AdS black holes are allowed as the static, spherically symmetric solutions.

Exponential Fall-Off Behavior of Regge Scatterings in Compactified Open String Theory

Song He, Jen-Chi Lee and Yi Yang — 2012-11-19T09:00:00+09:00

Authors: Song He, Jen-Chi Lee and Yi Yang
We calculate massive string scattering amplitudes ofcompactified open stringin the Regge regime. We extract the complete infinite ratios amonghigh-energy amplitudes of different string states in the fixed angle regimefrom these Regge string scattering amplitudes. The complete ratios calculatedby this indirect method include and extend the subset of ratios calculatedpreviously [J. C. Lee and Y. Yang, Nucl. Phys. B 784 (2007), 22;J. C. Lee, T. Takimi and Y. Yang, Nucl. Phys. B 804 (2008), 250]by the more difficult direct fixed anglecalculation. In this calculation of compactified open stringscattering, we discover a realization of arbitrary real values L in theidentity Eq. (4·18), rather than integer value only in all previoushigh-energy string scattering amplitude calculations. The identity inEq. (4·18) was explicitly proved recently in [J. C. Lee, C. H. Yan and Y. Yang, SIGMA 8 (2012), 045, arXiv:1012.5225]to link fixed angle and Regge string scattering amplitudes. In addition, we discover a kinematic regime with stringy highly winding modes, which shows the unusualexponential fall-off behavior in the Regge string scattering. This is complimentary with a kinematic regime discovered previously [J. C. Lee, T. Takimi and Y. Yang, Nucl. Phys. B 804 (2008), 250]which shows the unusual power-law behavior in the high-energy fixed anglecompactified string scatterings.

Massive Modes in Magnetized Brane Models

Yuta Hamada and Tatsuo Kobayashi — 2012-11-19T09:00:00+09:00

Authors: Yuta Hamada and Tatsuo Kobayashi
We study higher dimensional models with magnetic fluxes, which can be derived from superstring theory. We study mass spectrum and wavefunctions of massless and massive modes for spinor, scalar and vector fields.We compute the 3-point couplings and higher order couplings among massless modes and massive modes in 4D low-energy effective field theory.These couplings have non-trivial behaviors, because wavefunctions of massless and massive modes are non-trivial.

Separation of Chiral and Deconfinement Phase Transitions in Curved Space-Time

Shuji Sasagawa and Hidekazu Tanaka — 2012-11-19T09:00:00+09:00

Authors: Shuji Sasagawa and Hidekazu Tanaka
We calculated the chiral condensate and the dressed Polyakov loop in thespace-time R ×S^{3} and R ×H^{3}. The chiral condensate is theorder parameter for the chiral phase transition, whereas the dressed Polyakovloop is the order parameter for the deconfinement phase transition. When thereis a current mass, critical points for the chiral and deconfinement phasetransitions are different in the crossover region. We show that the differenceis changed by the gravitational effect.

Quark-Anti-Quark Potentials from Nambu-Bethe-Salpeter Amplitudes on Lattice

Yoichi Ikeda and Hideaki Iida — 2012-11-19T09:00:00+09:00

Authors: Yoichi Ikeda and Hideaki Iida
Quark–anti-quark (\barq-q) potentials with finite quark masses are studied from the \barq-q Nambu-Bethe-Salpeter (NBS) wave functions in quenched lattice QCD. With the use of a method which has been recently developed in the derivation of nuclear forces from lattice QCD,we derive the \barq-q potentials from the NBS wave functions.We calculate the \barq-q NBS wave functions in pseudo-scalar and vector channels for several quark masses.The derived potentials at each quark mass in both channels show linear plus Coulomb form. We also discuss the quark-mass and channel dependence of the \barq-q potentials.

Application of Fixed Scale Approach to Static Quark Free Energies in Quenched and 2 + 1 Flavor Lattice QCD with Improved Wilson Quark Action

2012-11-19T09:00:00+09:00

Authors: Yu Maezawa, Takashi Umeda, Sinya Aoki, Shinji Ejiri, Tetsuo Hatsuda, Kazuyuki Kanaya and Hiroshi Ohno (WHOT-QCD Collaboration)
The free energies of static quarks and the Debye screening masses in the quark gluon plasma are studied using Polyakov-line correlation functions in lattice QCD adopting the fixed-scale approach in which temperature is varied without changing the spatial volume and the renormalization factors.We calculate static-quark free energies in various color channels in the high temperature phase up to about 3.5 times the (pseudo-)critical temperature, performing lattice simulations both in quenched and 2 + 1 flavor QCD. For the quenched simulations, we adopt the plaquette gauge action on anisotropic 20^{3} ×N_{t} lattices with N_{t} = 8–26 at the renormalized anisotropy a_{s} / a_{t} ≃4. For 2 + 1 flavor QCD, we adopt the renormalization-group improved Iwasaki gluon action and the non-perturbatively O(a)-improved Wilson quark action on isotropic 32^{3} ×N_{t} lattices with N_{t} = 4–12 at m_{ PS}/m_{ V} = 0.63 (0.74) for the light (strange) flavors.We find that the color-singlet free energies at high temperatures converge to the zero-temperature static-quark potential evaluated from the Wilson-loop at short distances. This is in accordance with the theoretical expectation that the short distance physics is insensitive to the temperature. At long distances, the free energies approach twice the single-quark free energies, implying that the interaction between static quarks is fully screened.We find that the static-quark free energies for various color channels turn out to be well described by the screened Coulomb form, and the color-channel dependence of the inter-quark interaction can be described by the kinetic Casimir factor inspired from the lowest order perturbation theory.We also discuss comparison with a prediction of the thermal perturbation theory and flavor dependence of the screening masses.

Gravitational Waves from a Particle in Circular Orbits around a Schwarzschild Black Hole to the 22nd Post-Newtonian Order

Ryuichi Fujita — 2012-11-19T09:00:00+09:00

Authors: Ryuichi Fujita
We extend our previous results of the 14th post-Newtonian (PN) order expansion of gravitational waves for a test particle in circular orbits around a Schwarzschild black hole to the 22PN order, i.e. v^{44} beyond the leading Newtonian approximation where v is the orbital velocity of a test particle. Comparing our 22PN formula for the energy flux with high precision numerical results, we find that the relative error of the 22PN flux at the innermost stable circular orbit is about 10^{-5}. We also estimate the phase difference between the 22PN waveforms and numerical waveforms after a two-year inspiral. We find that the dephase is about 10^{-9} for µ/M = 10^{-4} and 10^{-2} for µ/M = 10^{-5} where µ is the mass of the compact object and M the mass of the central supermassive black hole. Finally, we construct a hybrid formula of the energy flux by supplementing the 4PN formula of the energy flux for circular and equatorial orbits around a Kerr black hole with all the present 22PN terms for the case of a Schwarzschild black hole. Comparing the hybrid formula with the the full numerical results, we examine the performance of the hybrid formula for the case of Kerr black hole.

Exact Stationary Solution Method for the Wadati-Konno-Ichikawa-Shimizu (WKIS) Equation

Robert A. Van Gorder — 2012-11-19T09:00:00+09:00

Authors: Robert A. Van Gorder
We consider a method of obtaining exact implicit relations governingstationary solutions to the Wadati-Konno-Ichikawa-Shimizu (WKIS) equation.After a suitable transform, we put the WKIS equation into the form of anonlinear ordinary differential equation. This equation has exact first andsecond integrals of motion. From this second integral, the exact equationgoverning the stationary solution to the WKIS equation is obtained. Thisrelation may easily be inverted and plotted, to give the exact solutionprofiles. Furthermore, an exact formula for the period of oscillation in termsof the model parameters is obtained.

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