著者

Boero Mauro Oshiyama Atsushi Silvestrelli Pier Luigi Murakami Kouichi

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.86, pp.201910, 2005-05

被引用文献数

17

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Recent experiments have shown that pure Si structures in a matrix of SiO2 can be formed by electron excitation techniques, with appealing applications in nanotechnology. Our ab initio simulations provide an insight into the underlying mechanism, showing that electron excitations weaken Si–O bonds in SiO2, dislodge O atoms and allow Si dangling bonds to reconstruct in stable Si–Si structures below the melting temperature. Differences in diffusivity of O (fast) and Si (slow) are shown to play a decisive role in the process.

著者

Makimura Tetsuya Miyamoto Hisao Kenmotsu Youichi Murakami Kouichi Niino Hiroyuki

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.86, no.10, pp.103111, 2005-03

被引用文献数

38 40

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We have investigated direct micromachining of quartz glass, using pulsed laser plasma soft x-rays (LPSXs) having a potential capability of nanomachining because the diffraction limit is ~10 nm. The LPSX's were generated by irradiation of a Ta target with 532 nm laser light from a conventional Q switched Nd:YAG laser at 700 mJ/pulse. In order to achieve a sufficient power density of LPSX's beyond the ablation threshold, we developed an ellipsoidal mirror to obtain efficient focusing of LPSXs at around 10 nm. It was found that quartz glass plates are smoothly ablated at 45 nm/shot using the focused and pulsed LPSX's.

著者

Hushur Anwar Shigematsu Hirotake Akishige Yukikuni Kojima Seiji

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.86, no.11, pp.112903, 2005-03

被引用文献数

28 25

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Ferroelectric single crystals of BaTi2O5 have been studied in detail by Raman and high-resolution micro-Brillouin scattering with a focus on the central component of the relaxation mode over a wide temperature range (20–600 °C). A relaxation mode has been clearly observed in these single crystals. The temperature dependences of the relaxation time and integrated intensity of the relaxation mode are well reproduced by the extended semiclassical tunneling model. The ferroelectric phase transition shows, at least near the vicinity of Tc, an order-disorder nature. Our results indicate that the spontaneous polarization mainly resulted from the dynamic disorder of the Ti ions in the octahedra along the polar b axis of BaTi2O5.

著者

Shabbir Ghulam Ko Jae-Hyeon Kojima Seiji

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.86, no.1, pp.012908, 2004-12

被引用文献数

11 10

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High-resolution Brillouin scattering experiments have been performed to investigate the low temperature "aging" effect in lanthanum lead zirconate titanate (PLZT) relaxor ferroelectric ceramics. From the temperature dependence of the frequency shift of longitudinal acoustic mode, an acoustic anomaly was observed at T0~46 K in these ceramics with clear "aging" effect below T0. The results have been discussed in the light of stepwise freezing of the related degrees of freedom causing transition from proper to improper dipole glassy states at T0.

著者

Konno Hidetoshi

出版者

Hindawi Publishing Corporation

雑誌

Advances in mathematical physics (ISSN:16879120)

巻号頁・発行日

vol.2010, pp.504267, 2010

被引用文献数

32 3

---

There are two types of master equations in describing nonequilibrium phenomena with memory effect: (i) the memory function type and (ii) the nonstationary type. A generalized Polya process is studied within the framework of a non-stationary type master equation approach. For a transition-rate with an arbitrary time-dependent relaxation function, the exact solution of a generalized Polya process is obtained. The characteristic features of temporal variation of the solution are displayed for some typical time-dependent relaxation functions reflecting memory in the systems.

著者

Taniguchi Yusuke

出版者

Institute of Physics Publishing

雑誌

Journal of high energy physics (ISSN:11266708)

巻号頁・発行日

vol.2006, no.10, pp.027, 2006-09

被引用文献数

9

---

Finite volume renormalization scheme is one of the most fascinating scheme for non-perturbative renormalization on lattice. By using the step scaling function one can follow running of renormalized quantities with reasonable cost. It has been established the Schrödinger functional is very convenient to define a field theory in a finite volume for this purpose. The Schrödinger functional, which is characterized by a Dirichlet boundary condition in temporal direction, is well defined and works well for the Yang-Mills theory and QCD. Furthermore it matches well with lattice regularization. However one easily runs into difficulties if one sets the same sort of the Dirichlet boundary condition for the overlap Dirac operator or the domain-wall fermion on lattice. In this paper we propose an orbifolding projection procedure to impose the Schrödinger functional Dirichlet boundary condition on the domain-wall fermion.

著者

Hatta Y. Iancu E. Mueller A. H.

出版者

Institute of Physics Publishing

雑誌

Journal of high energy physics (ISSN:11266708)

巻号頁・発行日

vol.2008, no.5, pp.37, 2008-05

被引用文献数

101 106

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Within the framework of the AdS/CFT correspondence, we study the timeevolution of an energetic R-current propagating through a finite temperature, stronglycoupled, N = 4 SYM plasma and propose a physical picture for our results. In thispicture, the current splits into a pair of massless partons, which then evolve via successivebranchings, in such a way that energy is quasi-democratically divided among the productsof a branching. We point out a duality between the transverse size of the partonic systemproduced through branching and the radial distance traveled by the dual Maxwell wave inthe AdS geometry. For a time-like current, the branching occurs already in the vacuum,where it gives rise to a system of low-momentum partons isotropically distributed in thetransverse plane. But at finite temperature, the branching mechanism is modified by themedium, in that the rate for parton splitting is enhanced by the transfer of transversemomentum from the partons to the plasma. This mechanism, which controls the partonenergy loss, is sensitive to the energy density in the plasma, but not to the details of thethermal state. We compute the lifetime of the current for various kinematical regimes andprovide physical interpretations for other, related, quantities, so like the meson screeninglength, the drag force, or the trailing string, that were previously computed via AdS/CFTtechniques.

著者

Hatta Yoshitaka Matsuo Toshihiro

出版者

IOP Publishing

雑誌

The journal of high energy physics (ISSN:11266708)

巻号頁・発行日

vol.2009, no.06, pp.011, 2009-06-04

被引用文献数

21 6

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Recently, an exact conformal mapping between soft gluons emitted from jets at large angle in e+e−-annihilation and those in the BFKL evolution of a high energy hadron has been proposed. We elucidate some remarkable aspects of this correspondence and use them to analytically compute the distribution and correlation of gluons in the interjet region. We also establish the timelike counterpart of Mueller's dipole model and discuss the resulting linear and nonlinear evolution equations.

著者

Hatta Yoshitaka Ueda Takahiro Xiao Bo-Wen

出版者

IOP Publishing

雑誌

The journal of high energy physics (ISSN:11266708)

巻号頁・発行日

vol.2009, no.08, pp.007, 2009-08-05

被引用文献数

35 16

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Using the AdS/CFT correspondence, we calculate the polarized structure functions in strongly coupled Script N = 4 supersymmetric Yang-Mills theory deformed in the infrared. We find that the flavor singlet contribution to the g1 structure function is vanishingly small, while the flavor non-singlet contribution shows the Regge behavior at small–x with an intercept slightly less than 1. We explicitly check that the latter satisfies the moment sum rule. We discuss the `spin crisis' problem and suggest that at strong coupling the spin of a hadron entirely comes from the orbital angular momentum.

著者

Sakai Kazuhiro Satoh Yuji

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.3, pp.77, 2010-03

被引用文献数

16

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We construct constant mean curvature surfaces of the general finite-gap type in AdS 3. The special case with zero mean curvature gives minimal surfaces relevant for the study of Wilson loops and gluon scattering amplitudes in $ \mathcal{N} = 4 $ super Yang-Mills. We also analyze properties of the finite-gap solutions including asymptotic behavior and the degenerate (soliton) limit, and discuss possible solutions with null boundaries.

著者

Avsar Emil Hatta Yoshitaka Matsuo Toshihiro

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.3, pp.37, 2010-03

被引用文献数

15 5

---

Based on the AdS/CFT correspondence, we present a holographic description of various C-odd exchanges in high energy baryon-(anti)baryon scattering, and calculate their respective contributions to the difference in the total cross sections. We show that, due to the warp factor of AdS 5, the single Odderon exchange gives a larger total cross section in baryon-baryon collisions than in baryon-antibaryon collisions at asymptotically high energies.

著者

Hatsuda Yasuyuki Ito Katsushi Sakai Kazuhiro Satoh Yuji

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.4, pp.108, 2010-04

被引用文献数

28 17

---

We study classical open string solutions with a null polygonal boundary in AdS 3 in relation to gluon scattering amplitudes in $$ \mathcal{N} = 4 $$ super Yang-Mills at strong coupling. We derive in full detail the set of integral equations governing the decagonal and the dodecagonal solutions and identify them with the thermodynamic Bethe ansatz equations of the homogeneous sine-Gordon models. By evaluating the free energy in the conformal limit we compute the central charges, from which we observe general correspondence between the polygonal solutions in AdS n and generalized parafermions.

著者

Aoki Sinya Balog Janos Weisz Peter

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.5, pp.8, 2010-05

被引用文献数

11 17

---

We investigate the short distance behavior of nucleon-nucleon (NN) potentials defined through Bethe-Salpeter wave functions, by perturbatively calculating anomalous dimensions of 6-quark operators in QCD. Thanks to the asymptotic freedom of QCD, 1-loop computations give certain exact results for the potentials in the zero distance limit. In particular the functional form of the S-state central NN potential at short distance r is predicted to be a little weaker than r −2. On the other hand, due to the intriguing character of the anomalous dimension spectrum, perturbative considerations alone can not determine whether this potential is repulsive or attractive at short distances. A crude estimation suggests that the force at short distance is repulsive, as found numerically in lattice QCD. A similar behavior is found for the tensor potential.

著者

Baba Yutaka Ishibashi Nobuyuki Murakami Koichi

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.8, pp.102, 2010-08

被引用文献数

7 5

---

We propose a dimensional regularization scheme to deal with the divergences caused by colliding supercurrents inserted at the interaction points, in the light-cone gauge NSR superstring field theory. We formulate the theory in d dimensions and define the amplitudes as analytic functions of d. With an appropriately chosen three-string interaction term and large negative d, the tree level amplitudes for the (NS,NS) closed strings can be recast into a BRST invariant form, using the superconformal field theory proposed in ref. [1]. We show that in the limit d →10 they coincide with the results of the first quantized theory. Therefore we obtain the desired results without adding any contact interaction terms to the action.

著者

Hatsuda Yasuyuki Ito Katsushi Sakai Kazuhiro Satoh Yuji

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.9, pp.64, 2010-09

被引用文献数

17 14

---

We study six-point gluon scattering amplitudes in $$ \mathcal{N} = 4 $$ super Yang-Mills theory at strong coupling by investigating the thermodynamic Bethe ansatz equations of the underlying $$ {\mathbb{Z}_4} $$-symmetric integrable model both analytically and numerically. By the conformal field theory (CFT) perturbation, we compute the free energy part of the remainder function with generic chemical potential near the CFT/small mass limit. Combining this with the expansion of the Y-functions, we obtain the remainder function near the small mass limit up to a function of the chemical potential, which can be evaluated numerically. We also find the leading corrections to the remainder function near the large mass limit. We confirm that these results are in good agreement with numerical computations.

著者

Kimura Taro Komatsu Shota Misumi Tatsuhiro Noumi Toshifumi Torii Shingo Aoki Sinya

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2012, no.1, pp.048, 2012-01

被引用文献数

16

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Employing the spin-flavor representation, we investigate the structures of the doubler-mixing symmetries and the mechanisms of their spontaneous breakdown in four types of lattice fermion formulation. We first revisit the U(4) × U(4) symmetries of the naive fermion with the vanishing bare mass m, and re-express them in terms of the spinflavor representation. We apply the same method to the Wilson fermion, which possesses only the U(1) vector symmetry for general values of m. For a special value of m, however, there emerges an additional U(1) symmetry to be broken by pion condensation. We also explore two types of minimally doubled fermion, and discover a similar kind of symmetry enhancement and its spontaneous breakdown.

著者

Aoki Sinya Balog Janos Weisz Peter

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

no.9, pp.83, 2010-09

被引用文献数

7 13

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The short distance behavior of baryon-baryon potentials defined throughNambu-Bethe-Salpeter wave functions is investigated using the operator product expansion.In a previous analysis of the nucleon-nucleon case, corresponding to the SU(3) channels27s and 10a, we argued that the potentials have a repulsive core. A new feature occursfor the case of baryons made up of three flavors: manifestly asymptotically attractive potentialsappear in the singlet and octet channels. Attraction in the singlet channel wasfirst indicated by quark model considerations, and recently been found in numerical latticesimulations. The latter have however not yet revealed asymptotic attraction in the octetchannels; we give a speculative explanation for this apparent discrepancy.

著者

Ishibashi Nobuyuki Murakami Koichi

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2011, no.1, pp.8, 2011-01

被引用文献数

6 4

---

Light-cone gauge superstring theory in noncritical dimensions corresponds to a worldsheet theory with nonstandard longitudinal part in the conformal gauge. The longitudinal part of the worldsheet theory is a superconformal field theory called X ± CFT. We show that the X ± CFT combined with the super-reparametrization ghost system can be described by free variables. It is possible to express the correlation functions in terms of these free variables. Bosonizing the free variables, we construct the spin fields and BRST invariant vertex operators for the Ramond sector in the conformal gauge formulation. By using these vertex operators, we can rewrite the tree amplitudes of the noncritical light-cone gauge string field theory, with external lines in the (R,R) sector as well as those in the (NS,NS) sector, in a BRST invariant way.

著者

Hatta Y. Iancu E. Mueller A. H. Triantafyllopoulos D. N.

出版者

Published for SISSA by Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2011, no.2, pp.065, 2011-02

被引用文献数

19

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We show that a source which radiates in the vacuum of the strongly coupled N = 4=4 SYM theory produces an energy distribution which, in the supergravity approximation, has the same space-time pattern as the corresponding classical distribution: the radiation propagates at the speed of light without broadening. We illustrate this on the basis of several examples: a small perturbation propagating down a steady string, a massless particle falling into AdS5, and the decay of a time-like wave-packet. A similar observation was made in Phys. Rev. D81 (2010) 126001 for the case of a rotating string. In all these cases, the absence of broadening is related to the fact that the energy backreaction on the boundary arises exclusively from the bulk perturbation at, or near, the boundary. This is so since bulk sources which propagate in AdS5 at the speed of light do not generate any energy on the boundary. We interpret these features as an artifact of the supergravity approximation, which fails to encode quantum mechanical fluctuations that should be present even in the strong coupling limit. We argue that such fluctuations should enter the dual string theory as longitudinal string fluctuations, which are not suppressed at strong coupling. We heuristically estimate the effects of such fluctuations and argue that they restore the broadening of the radiation, in agreement with expectations from both quantum mechanics and the ultraviolet/infrared correspondence.

著者

Hatsuda Yasuyuki Ito Katsushi Sakai Kazuhiro Satoh Yuji

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2011, no.4, pp.100, 2011-04

被引用文献数

13

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We study gluon scattering amplitudes/Wilson loops in =4 super Yang-Mills theory at strong coupling by calculating the area of the minimal surfaces in AdS 3 based on the associated thermodynamic Bethe ansatz system. The remainder function of the amplitudes is computed by evaluating the free energy, the T- and Y-functions of the homogeneous sine-Gordon model. Using conformal field theory (CFT) perturbation, we examine the mass corrections to the free energy around the CFT point corresponding to the regular polygonal Wilson loop. Based on the relation between the T-functions and the g-functions, which measure the boundary entropy, we calculate corrections to the T-and Y-functions as well as express them at the CFT point by the modular S-matrix. We evaluate the remainder function around the CFT point for 8 and 10-point amplitudes explicitly and compare these analytic expressions with the 2-loop formulas. The two rescaled remainder functions show very similar power series structures.