Results for "H. Kotegawa"

total 85632took 0.12s
Abrupt Emergence of Pressure-Induced Superconductivity of 34 K in SrFe2As2: A Resistivity Study under PressureOct 27 2008Nov 19 2008We report resistivity measurement under pressure in single crystals of SrFe_2As_2, which is one of the parent materials of Fe-based superconductors. The structural and antiferromagnetic (AFM) transition of T_0 = 198 K at ambient pressure is suppressed ... More
Effect of Uniaxial Stress for Pressure-Induced Superconductor SrFe_2As_2Apr 29 2009Jun 17 2009We report that the pressure-temperature phase diagram of single-crystalline SrFe$_2$As$_2$ is easily affected by the hydrostaticity of a pressure-transmitting medium. For all of the three mediums we used, superconductivity with zero resistance appears, ... More
Nonsaturating large magnetoresistance in the high carrier density nonsymmorphic metal CrPMar 14 2019The band structure of high carrier density metal CrP features an interesting crossing at the Y point of the Brillouin zone. The crossing, which is protected by the nonsymmorphic symmetry of the space group, results in a hybrid, semi-Dirac-like energy-momentum ... More
Evidence for Strong-coupling S-wave Superconductivity in MgB2 :11B NMR StudyFeb 19 2001We have investigated a gap structure in a newly-discovered superconductor, MgB2 through the measurement of 11B nuclear spin-lattice relaxation rate, ^{11}(1/T_1). ^{11}(1/T_1) is proportional to the temperature (T) in the normal state, and decreases exponentially ... More
Contrasting Pressure Effects in Sr2VFeAsO3 and Sr2ScFePO3Aug 11 2009Oct 27 2009We report the resistivity measurements under pressure of two Fe-based superconductors with a thick perovskite oxide layer, Sr2VFeAsO3 and Sr2ScFePO3. The superconducting transition temperature Tc of Sr2VFeAsO3 markedly increases with increasing pressure. ... More
Sb-NQR probe for superconducting property in the Pr-based filled skutterudite compound PrRu4Sb12Mar 27 2003We report the electronic and superconducting properties in the Pr-based filled-skutterudite superconductor PrRu$_4$Sb$_{12}$ with $T_c = 1.3$ K via the measurements of nuclear-quadrupole-resonance (NQR) frequency $\nu_Q$ and nuclear-spin-lattice-relaxation ... More
Pressure-Temperature-Magnetic Field Phase Diagram of Ferromagnetic Kondo Lattice CeRuPONov 06 2013We report the temperature-pressure-magnetic field phase diagram made from electrical resistivity measurements for the ferromagnetic (FM) Kondo lattice CeRuPO. The ground state at zero field changes from the FM state to another state, which is suggested ... More
Evidence for Unconventional Superconductivity in Arsenic-Free Iron-Based Superconductor FeSe : A ^77Se-NMR StudyJul 31 2008Sep 09 2008We report the results of $^{77}$Se--nuclear magnetic resonance (NMR) in $\alpha$-FeSe, which exhibits a similar crystal structure to the LaFeAsO$_{1-x}$F$_x$ superconductor and shows superconductivity at 8 K. The nuclear-spin lattice relaxation rate $1/T_1$ ... More
Evidence for High-frequency Phonon Mediated S-wave Superconductivity : 11B-NMR Study of Al-doped MgB2Jan 31 2002We report $^{11}$B-NMR study on Al-doped MgB$_2$ that addresses a possible mechanism for a high superconducting (SC) transition temperature ($T_c$) of $\sim 40$ K in recently discovered MgB$_2$. The result of nuclear spin lattice relaxation rate $1/T_1$ ... More
Precise Pressure Dependence of the Superconducting Transition Temperature of FeSe: Resistivity and ^77Se--NMR StudyMar 15 2009Apr 20 2009We report the precise pressure dependence of FeSe from a resistivity measurement up to 4.15 GPa. Superconducting transition temperature (T_c) increases sensitively under pressure, but shows a plateau between 0.5-1.5 GPa. The maximum T_c, which is determined ... More
NMR Investigation of the iron-based superconductors Ca4(Mg,Ti)3Fe2As2O8-y and Ca5(Sc,Ti)4Fe2As2O11-yOct 22 2012$^{75}$As and $^{45}$Sc NMR measurements unravel the electronic state for Fe-based superconductors with perovskite-type blocking layers Ca$_4$(Mg,Ti)$_3$Fe$_2$As$_2$O$_{8-y}$ ($T_c^{onset}=47$ K) and Ca$_5$(Sc,Ti)$_4$Fe$_2$As$_2$O$_{11-y}$ ($T_c^{onset}=41$ ... More
Anion height dependence of Tc for the Fe-based superconductorJan 12 2010Mar 13 2010We have established a plot of the anion height dependence of Tc for the typical Fe-based superconductors. The plot appeared a symmetric curve with a peak around 1.38 A. Both data at ambient pressure and under high pressure obeyed the unique curve. This ... More
Quasilinear quantum magnetoresistance in pressure-induced nonsymmorphic superconductor CrAsDec 22 2016In conventional metals, modification of electron trajectories under magnetic field gives rise to a magnetoresistance that varies quadratically at low field, followed by a saturation at high field for closed orbits on the Fermi surface. Deviations from ... More
Evidence for Unconventional Strong-coupling Superconductivity in PrOs_4Sb_12 : An Sb Nuclear Quadrupole Resonance (NQR) StudySep 04 2002Sep 05 2002We report Sb-NQR results which evidence a heavy-fermion (HF) behavior and an unconventional superconducting (SC) property in the filled-skutterudite compound PrOs_4Sb_12 revealing a SC transition temperature T_c=1.85 K. The temperature (T) dependence ... More
Evidence for unconventional superconducting fluctuations in heavy-fermion compound CeNi2Ge2Mar 09 2006We present evidence for unconventional superconducting fluctuations in a heavy-fermion compound CeNi$_2$Ge$_2$. The temperature dependence of the $^{73}$Ge nuclear-spin-lattice-relaxation rate $1/T_1$ indicates the development of magnetic correlations ... More
Coexistence of Superconductivity and Antiferromagnetism in Multilayered High-$T_c$ Superconductor HgBa$_2$Ca$_4$Cu$_5$O$_y$: A Cu-NMR StudyJan 22 2004We report a coexistence of superconductivity and antiferromagnetism in five-layered compound HgBa$_2$Ca$_4$Cu$_5$O$_y$ (Hg-1245) with $T_c=108$ K, which is composed of two types of CuO$_2$ planes in a unit cell; three inner planes (IP's) and two outer ... More
Evidence for Uniform Coexistence of Ferromagnetism and Unconventional Superconductivity in UGe_2: A ^73Ge-NQR Study under PressureDec 13 2004We report on the itinerant ferromagnetic superconductor UGe_2 through ^73Ge-NQR measurements under pressure (P). The P dependence of the NQR spectrum signals a first-order transition from the low-temperature (T) and low-P ferromagnetic phase (FM2) to ... More
Superconductivity of 2.2 K under Pressure in Helimagnet CrAsJul 05 2014Aug 04 2014We report resistivity measurements of the helimagnet CrAs under pressures. The helimagnetic transition with T_N ~ 265 K at ambient pressure is completely suppressed above a critical pressure of P_c ~ 0.7 GPa, and superconductivity is observed at ~2.2 ... More
Evolution toward Quantum Critical End Point in UGe_2Jul 05 2011We report on Hall resistivity and electrical resistivity measurements under pressure and magnetic field in UGe_2 with ferromagnetic (FM) tricriticality. The Hall resistivity sensitively detects the first order metamagnetic transition from a paramagnetic ... More
Ferromagnetic Quantum Critical Endpoint in UCoAlJul 22 2011Resistivity and magnetostriction measurements were performed at high magnetic fields and under pressure on UCoAl. At ambient pressure, the 1st order metamagnetic transition at H_m ~ 0.7 T from the paramagnetic ground state to the field-induced ferromagnetic ... More
Novel Phase Transition Near the Quantum Critical Point in the Filled-Skutterudite Compound CeOs4Sb12: an Sb-NQR StudyJul 20 2005We report on a novel phase transition at $T$ = 0.9 K in the Ce-based filled-skutterudite compound CeOs$_{4}$Sb$_{12}$ via measurements of the nuclear-spin lattice relaxation rate $1/T_{1}$ and nuclear quadrupole resonance (NQR) spectrum of Sb nuclei. ... More
Pressure Dependence of Superconducting Transition Temperature on Perovskite-Type Fe-Based Superconductors and NMR Study of Sr2VFeAsO3Sep 28 2010We report the pressure dependences of the superconducting transition temperature (T_c) in several perovskite-type Fe-based superconductors through the resistivity measurements up to ~4 GPa. In Ca_4(Mg,Ti)_3Fe_2As_2O_y with the highest T_c of 47 K in the ... More
Weak Spin Fluctuation with Finite Wave Vector and Superconducting Gap Symmetry in KxFe2-ySe2: 77Se Nuclear Magnetic ResonanceJun 08 2012Aug 22 2012We report $^{77}$Se-nuclear magnetic resonance (NMR) results down to sufficiently low temperatures under magnetic fields parallel to both the $ab$-plane and the c-axis in a paramagnetic/superconducting (PM/SC) phase of K$_x$Fe$_{2-y}$Se$_2$. The observation ... More
Strong Suppression of Coherence Effect and Appearance of Pseudogap in Layered Nitride Superconductor Li_xZrNCl: ^91Zr- and ^15N- NMR StudiesJul 11 2014We present NMR measurements of the layered nitride superconductor Li_xZrNCl. The nuclear spin-lattice relaxation rate, 1/T_1, shows that the coherence peak is strongly suppressed in Li_xZrNCl in contrast to conventional BCS superconductors. In the lightly-doped ... More
Detection of an Unconventional Superconducting Phase in the Vicinity of the Strong First-Order Magnetic Transition in CrAs Using ^75As-Nuclear Quadrupole ResonanceAug 14 2014Mar 11 2015Pressure-induced superconductivity was recently discovered in the binary helimagnet CrAs. We report the results of measurements of nuclear quadrupole resonance for CrAs under pressure. In the vicinity of the critical pressure P_c between the helimagnetic ... More
Possible Superconducting Symmetry and Magnetic Correlations in K0.8Fe2Se2: A 77Se-NMR StudyJan 24 2011Apr 12 2011We report ^77Se-NMR measurements in the recent discovered K_0.8Fe_2Se_2 with the superconducting transition temperature T_c=32 K. The characteristic point of this system is that the high density of state is located in the vicinity of the Fermi level. ... More
Pressure-Induced Superconductivity in Mineral Calaverite AuTe2Sep 18 2013Oct 07 2013The pressure dependences of resistivity and ac susceptibility have been measured in the mineral calaverite AuTe$_2$. Resistivity clearly shows a first-order phase transition into a high-pressure phase, consistent with the results of a previous structural ... More
Phase diagram of CeRuPO under pressure investigated by $^{31}$P-NMR - Comparison between CeRuPO under pressure and the Ce(Ru$_{1-x}$Fe$_{x}$)PO system -Oct 08 2014We have performed $^{31}$P-NMR measurements on single-crystalline CeRuPO under pressure in order to understand the variation in magnetic character against pressure. The NMR spectra for $H \perp c$ and $H \parallel c$ at 2.15GPa split below the ordered ... More
Cooperative Phenomenon of Ferromagnetism and Unconventional Superconductivity in UGe$_2$: A ^73^Ge-NQR Study under PressureAug 30 2005We report on a cooperative phenomenon of ferromagnetism and unconventional superconductivity (SC) in UGe$_2$ through the measurements of $^{73}$Ge nuclear-quadrupole-resonance (NQR) under pressure ($P$). The NQR spectra evidenced phase separation into ... More
Pressure Study of BiS2-Based Superconductors Bi4O4S3 and La(O,F)BiS2Jul 30 2012Aug 20 2012We report the electrical resistivity measurements under pressure for the recently discovered BiS2-based layered superconductors Bi4O4S3 and La(O,F)BiS2. In Bi4O4S3, the transition temperature Tc decreases monotonically without a distinct change in the ... More
Superconductivity in New Iron Pnictide Oxide (Fe2As2)(Sr4(Mg,Ti)2O6)Dec 09 2009We have discovered a new iron pnictide oxide superconductor (Fe2As2)(Sr4(Mg,Ti)2O6). This material is isostructual with (Fe2As2)(Sr4M2O6) (M = Sc, Cr, V), which were found in previous studies. The structure of this compound is tetragonal with a space ... More
Strong Longitudinal Magnetic Fluctuations near Critical End Point in UCoAl: A ^59Co-NMR StudyJul 26 2011We report ^59Co-NMR measurements in UCoAl where a metamagnetism occurs due to enhancement of ferromagnetism by magnetic field. The metamagnetic transition from a paramagnetic (PM) state to a ferromagnetic state is a first order transition at low temperatures, ... More
73Ge-NMR/NQR Investigation of Magnetic Properties of URhGeMar 16 2015We report 73Ge-NMR and NQR results for ferromagnetic (FM) superconductor URhGe. The magnitude and direction of the internal field, H_int, and parameters of the electric field gradient at the Ge site were determined experimentally. Using powdered polycrystalline ... More
Superconductivity Reinforced by Magnetic Field and the Magnetic Instability in Uranium FerromagnetsDec 09 2010We review our recent results on ferromagnetic superconductors, URhGe and UCoGe. High quality single crystals of both compounds were successfully grown. The specific heat shows a clear jump related to the superconducting transition in UCoGe. The finite ... More
New Superconducting and Magnetic Phases Emerge on the Verge of Antiferromagnetism in CeIn$_3$Apr 16 2004We report the discovery of new superconducting and novel magnetic phases in CeIn$_3$ on the verge of antiferromagnetism (AFM) under pressure ($P$) through the In-nuclear quadrupole resonance (NQR) measurements. We have found a $P$-induced phase separation ... More
Decoupling between Field-instabilities of Antiferromagnetism and Pseudo-metamagnetism in Rh-doped CeRu2Si2 Kondo LatticeJan 23 2012Doping Kondo lattice system CeRu2Si2 with Rh-8% (Ce(Ru0.92Rh0.08)2Si2) leads to drastic consequences due to the mismatch of the lattice parameters between CeRu2Si2 and CeRh2Si2. A large variety of experiments clarifies the unusual properties of the ground ... More
Rhythmic cluster generation in strongly driven colloidal dispersionsJun 28 2006We study the response of a nematic colloidal dispersion of rods to a driven probe particle which is dragged with high speed through the dispersion perpendicular to the nematic director. In front of the dragged particle, clusters of rods are generated ... More
Field-induced Phenomena in Ferromagnetic Superconductors UCoGe and URhGeJan 14 2012We review our recent studies on ferromagnetic superconductors, UGe2, URhGe and UCoGe, where the spin-triplet state with the so-called equal spin pairing is realized. We focus on experimental results of URhGe and UCoGe in which the superconductivity occurs ... More
Aggregation of self-propelled colloidal rods near confining wallsSep 03 2008Non-equilibrium collective behavior of self-propelled colloidal rods in a confining channel is studied using Brownian dynamics simulations and dynamical density functional theory. We observe an aggregation process in which rods self-organize into transiently ... More
Cooperative single-photon subradiant states in a three-dimensional atomic arrayJun 21 2016We propose a complete superradiant and subradiant states that can be manipulated and prepared in a three-dimensional atomic array. These subradiant states can be realized by absorbing a single photon and imprinting the spatially-dependent phases on the ... More
Effects of Spin Fluctuations in Quasi-One-Dimensional Organic SuperconductorsMay 05 1999We study the electronic states of quasi-one-dimensional organic conductors using the single band Hubbard model at half-filling. We treat the effects of the on-site Coulomb interaction by the fluctuation-exchange (FLEX) method, and calculate the phase ... More
Application of the Limit Cycle Model to Star Formation Histories in Spiral Galaxies: Variation among Morphological TypesMay 04 2000We propose a limit-cycle scenario of star formation history for any morphological type of spiral galaxies. It is known observationally that the early-type spiral sample has a wider range of the present star formation rate (SFR) than the late-type sample. ... More
On the extrapolation of perturbation seriesDec 21 2002We discuss certain special cases of algebraic approximants that are given as zeroes of so-called "effective characteristic polynomials" and their generalization to a multiseries setting. These approximants are useful for the convergence acceleration or ... More
The size-extensitivity of correlation energy estimators based on effective characteristic polynomialsApr 08 1997Estimators $\Pi n$ for the correlation energy can be computed as roots of effective characteristic polynomials of degree $n$. The coefficients of these polynomials are derived from the terms of the perturbation series of the energy. From a fourth-order ... More
Integrability and Canonical Structure of d=2, N=16 SupergravityApr 23 1998Jul 01 1998The canonical formulation of d=2, N=16 supergravity is presented. We work out the supersymmetry generators (including all higher order spinor terms) and the N=16 superconformal constraint algebra. We then describe the construction of the conserved non-local ... More
Inherent global stabilization of unstable local behavior in coupled map latticesJul 05 2004The behavior of two-dimensional coupled map lattices is studied with respect to the global stabilization of unstable local fixed points without external control. It is numerically shown under which circumstances such inherent global stabilization can ... More
Quark mean field model for nuclear matter and finite nucleiNov 15 1999We study nuclear matter and finite nuclei in terms of the quark mean field (QMF) model, in which we describe the nucleon using the constituent quark model. The meson mean fields, in particular the sigma meson, created by other nucleons act on quarks inside ... More
A focusable, convergent fast-electron beam from ultra-high-intensity laser-solid interactionsJan 29 2015A novel scheme for the creation of a convergent, or focussing, fast-electron beam generated from ultra-high-intensity laser-solid interactions is described. Self-consistent particle-in-cell simulations are used to demonstrate the efficacy of this scheme ... More
Pentaquark $Θ^+$ in nuclear matter and $Θ^+$ hypernucleiOct 17 2004Jul 05 2005We study the properties of the $\Theta^+$ in nuclear matter and $\Theta^+$ hypernuclei within the quark mean-field (QMF) model, which has been successfully used for the description of ordinary nuclei and $\Lambda$ hypernuclei. With the assumption that ... More
Comment on "Conjectures on exact solution of three-dimensional (3D) simple orthorhombic Ising lattices" [arXiv:0705.1045]Nov 12 2008Nov 22 2008It is shown that a recent article by Z.-D. Zhang [arXiv:0705.1045] is in error and violates well-known theorems.
A Simple Method to Reduce Thermodynamic Derivatives by ComputerJan 09 2014Studies in thermodynamics often require the reduction of some first or second order partial derivatives in terms of a smaller basic set. A simple algorithm to perform such a reduction is presented here, together with a review of earlier related works. ... More
Variational Calculation of Effective Classical Potential at $T \neq 0$ to Higher OrdersApr 16 1995Using the new variational approach proposed recently for a systematic improvement of the locally harmonic Feynman-Kleinert approximation to path integrals we calculate the partition function of the anharmonic oscillator for all temperatures and coupling ... More
Entropy of entanglement in continuous frequency space of the biphoton state from multiplexed cold atomic ensemblesJan 05 2016We consider a scheme of multiplexed cold atomic ensembles that generate a frequency-entangled biphoton state with controllable entropy of entanglement. The biphoton state consists of a telecommunication photon (signal) immediately followed by an infrared ... More
On K(E_9)Jul 08 2004We study the maximal compact subgroup K(E_9) of the affine Lie group E_9(9) and its on-shell realization as an R symmetry of maximal N=16 supergravity in two dimensions. We first give a rigorous definition of the group K(E_9), which lives on the double ... More
Compact and Noncompact Gauged Maximal Supergravities in Three DimensionsMar 06 2001Apr 21 2001We present the maximally supersymmetric three-dimensional gauged supergravities. Owing to the special properties of three dimensions -- especially the on-shell duality between vector and scalar fields, and the purely topological character of (super)gravity ... More
A nontrivial solvable noncommutative φ^3 model in 4 dimensionsMar 07 2006May 24 2006We study the quantization of the noncommutative selfdual \phi^3 model in 4 dimensions, by mapping it to a Kontsevich model. The model is shown to be renormalizable, provided one additional counterterm is included compared to the 2-dimensional case which ... More
Renormalization of the noncommutative phi^3 model through the Kontsevich modelDec 16 2005We point out that the noncommutative selfdual phi^3 model can be mapped to the Kontsevich model, for a suitable choice of the eigenvalues in the latter. This allows to apply known results for the Kontsevich model to the quantization of the field theory, ... More
Transition Amplitudes within the Stochastic Quantization SchemeSep 30 1993Quantum mechanical transition amplitudes are calculated within the stochastic quantization scheme for the free nonrelativistic particle, the harmonic oscillator and the nonrelativistic particle in a constant magnetic field; we close with free Grassmann ... More
Independent Component Analysis of Spatiotemporal ChaosMay 13 2005Two types of spatiotemporal chaos exhibited by ensembles of coupled nonlinear oscillators are analyzed using independent component analysis (ICA). For diffusively coupled complex Ginzburg-Landau oscillators that exhibit smooth amplitude patterns, ICA ... More
Superradiant laser: Effect of long-ranged dipole-dipole interactionSep 02 2016We theoretically investigate the effect of long-ranged dipole-dipole interaction (LRDDI) on a superradiant laser (SL). This effect is induced from the atom-photon interaction in the dissipation process. In the bad-cavity limit usually performed to initiate ... More
Supereigenvalue Model and Dijkgraaf-Vafa ProposalApr 22 2003We present a variant of the supereigenvalue model proposed before by Alvarez-Gaume, Itoyama, Manes, and Zadra. This model derives a set of three planar loop equations which takes the same form as the set of three anomalous Ward-Takahashi identities on ... More
Scalar Levin-Type Sequence TransformationsMay 22 2000Sequence transformations are important tools for the convergence acceleration of slowly convergent scalar sequences or series and for the summation of divergent series. Transformations that depend not only on the sequence elements or partial sums $s_n$ ... More
Theory of the Hall Coefficient and the Resistivity on the Layered Organic Superconductors κ-(BEDT-TTF)Nov 20 2000Feb 22 2001In the organic superconducting \kappa-(BEDT-TTF) compounds, various transport phenomena exhibit striking non-Fermi liquid behaviors, which should be the important clues to understanding the electronic state of this system. Especially, the Hall coefficient ... More
Thermodynamical description of modified generalized Chaplygin gas model of dark energyApr 10 2015May 17 2016We consider a universe filled by a modified generalized Chaplygin gas together with a pressureless dark matter component. We get a thermodynamical interpretation for the modified generalized Chaplygin gas confined to the apparent horizon of FRW universe, ... More
Stabilization of causally and non-causally coupled map latticesJul 07 2004Two-dimensional coupled map lattices have global stability properties that depend on the coupling between individual maps and their neighborhood. The action of the neighborhood on individual maps can be implemented in terms of "causal" coupling (to spatially ... More
Asymptotic function for multi-growth surfaces using power-law noiseNov 06 2002Numerical simulations are used to investigate the multiaffine exponent $\alpha_q$ and multi-growth exponent $\beta_q$ of ballistic deposition growth for noise obeying a power-law distribution. The simulated values of $\beta_q$ are compared with the asymptotic ... More
Study of $Λ$ hypernuclei in the quark mean field modelApr 24 2001Jul 11 2001We extend the quark mean field model to the study of $\Lambda$ hypernuclei. Without adjusting parameters, the properties of $\Lambda$ hypernuclei can be described reasonably well. The small spin-orbit splittings for $\Lambda$ in hypernuclei are achieved, ... More
Comment on `Mathematical structure of the three-dimensional (3D) Ising model'Jul 06 2013The review paper by Zhang Zhi-Dong contains many errors and is based on several earlier works that are equally wrong.
Scalings between Physical and their Observationally related Quantities of Merger RemnantsSep 07 2005We present scaling relations between the virial velocity (V) and the one-dimensional central velocity dispersion (Sig0); the gravitational radius (Rv) and the effective radius (Re); and the total mass (M) and the luminous mass (ML) found in N-body simulations ... More
Superradiant cascade emissions in an atomic ensemble via four-wave mixingJan 21 2015May 04 2015We investigate superradiant cascade emissions from an atomic ensemble driven by two-color classical fields. The correlated pair of photons (signal and idler) is generated by adiabatically driving the system with large-detuned light fields via four-wave ... More
Spectral analysis for cascade-emission-based quantum communication in atomic ensemblesMar 11 2014The ladder configuration of atomic levels provides a source for telecom photons (signal) from the upper atomic transition. \ For rubidium and cesium atoms, the signal field has the range around 1.3-1.5 $\mu$m that can be coupled to an optical fiber and ... More
Positive-P phase space method simulation in superradiant emission from a cascade atomic ensembleJan 12 2012The superradiant emission properties from an atomic ensemble with cascade level configuration is numerically simulated. The correlated spontaneous emissions (signal then idler fields) are purely stochastic processes which are initiated by quantum fluctuations. ... More
AdS/CFT correspondence in the Euclidean contextNov 02 2006May 23 2007We study two possible prescriptions for AdS/CFT correspondence by means of functional integrals. The considerations are non-perturbative and reveal certain divergencies which turn out to be harmless, in the sense that reflection-positivity and conformal ... More
Correlation Energy Estimators based on Møller-Plesset Perturbation TheoryMar 05 1996Some methods for the convergence acceleration of the M{\o}ller-Plesset perturbation series for the correlation energy are discussed. The order-by-order summation is less effective than the Feenberg series. The latter is obtained by renormalizing the unperturbed ... More
N=8 matter coupled AdS_3 supergravitiesJun 18 2001Following the recent construction of maximal (N=16) gauged supergravity in three dimensions, we derive gauged D=3, N=8 supergravities in three dimensions as deformations of the corresponding ungauged theories with scalar manifolds SO(8,n)/(SO(8)x SO(n)). ... More
Maximal gauged supergravity in three dimensionsOct 11 2000Jan 07 2001We construct maximally supersymmetric gauged N=16 supergravity in three dimensions, thereby obtaining an entirely new class of AdS supergravities. These models are not derivable from any known higher-dimensional theory, indicating the existence of a new ... More
Surface anisotropy in nanomagnets: transverse or Néel ?Jul 17 2003Mar 31 2004Through the hysteresis loop and magnetization spatial distribution we study and compare two models for surface anisotropy in nanomagnets: a model with transverse anisotropy axes and N\'eel's model. While surface anisotropy in the transverse model induces ... More
String-Scale BaryogenesisMar 25 1997Mar 26 1997Baryogenesis scenarios at the string scale are considered. The observed baryon to entropy ratio, $n_B /s \sim 10^{-10}$, can be explained in these scenarios.
Thermodynamic of universe with a varying dark energy componentMay 04 2015Aug 03 2015We consider a FRW universe filled by a dark energy candidate together with other possible sources which may include the baryonic and non-baryonic matters. Thereinafter, we consider a situation in which the cosmos sectors do not interact with each other. ... More
Analysis of the thermal cross section of the capture reaction 13C(n,gamma)14COct 02 1997We investigate the thermal cross section of the reaction 13C(n,gamma)14}C which takes place in the helium burning zones of red giant star as well as in the nucleosynthesis of Inhomogeneous Big Bang models. We find that we can reproduce the experimentally ... More
The two-fermion vector potential of constraint theory from Feynman diagramsOct 16 1995The relativistic fermion-antifermion bound state vector potential of constraint theory is calculated, in perturbation theory, by means of the Lippmann-Schwinger type equation that relates it to the scattering amplitude. Leading contributions of n-photon ... More
Energy and decay width of the pi-K atomMay 24 2006The energy and decay width of the pi-K atom are evaluated in the framework of the quasipotential-constraint theory approach. The main electromagnetic and isospin symmetry breaking corrections to the lowest-order formulas for the energy shift from the ... More
Whitham Prepotential and SuperpotentialDec 30 2003Jan 24 2004N=2 supersymmetric U(N) Yang-Mills theory softly broken to N=1 by the superpotential of the adjoint scalar fields is discussed from the viewpoint of the Whitham deformation theory for prepotential. With proper identification of the superpotential we derive ... More
Onsager algebra and cluster XY-models in a transverse magnetic fieldOct 10 2017Nov 09 2017The correlation functions of certain $n$-cluster XY models are explicitly expressed in terms of those of the standard Ising chain in transverse field.
Effect of size polydispersity on the pitch of nanorod cholestericsMar 14 2019Many nanoparticle-based chiral liquid crystals are composed of polydisperse rod-shaped particles with considerable spread in size or shape, affecting the mesoscale chiral properties in, as yet, unknown ways. Using an algebraic interpretation of Onsager-Straley ... More
Molecular dynamics simulation of aging in amorphous silicaDec 06 1999By means of molecular dynamics simulations we examine the aging process of a strong glass former, a silica melt modeled by the BKS potential. The system is quenched from a temperature above to one below the critical temperature, and the potential energy ... More
An indefinite metric model for interacting quantum fields with non-stationary background gravitationAug 25 2004We consider a relativistic Ansatz for the vacuum expectation values (VEVs) of a quantum field on a globally hyperbolic space-time which is motivated by certain Euclidean field theories. The Yang-Feldman asymptotic condition w.r.t. a "in"-field in a quasi-free ... More
Boundary blow-up solutions of elliptic equations involving regional fractional LaplacianFeb 09 2016In this paper, we study existence of boundary blow-up solutions for elliptic equations involving regional fractional Laplacian. We also discuss the optimality of our results.
A 5D noncompact Kaluza -Klein cosmology in the presence of Null perfect fluidMay 18 2010Jun 08 2011For the description of the early inflation, and acceleration expansion of the Universe, compatible with observational data, the 5D noncompact Kaluza--Klein cosmology is investigated. It is proposed that the 5D space is filled with a null perfect fluid, ... More
Schwinger-Dyson and Large $N_{c}$ Loop Equation for Supersymmetric Yang-Mills TheoryApr 04 1996We derive an infinite sequence of Schwinger-Dyson equations for $N=1$ supersymmetric Yang-Mills theory. The fundamental and the only variable employed is the Wilson-loop geometrically represented in $N=1$ superspace: it organizes an infinite number of ... More
The Early History of the Integrable Chiral Potts Model and the Odd-Even ProblemNov 26 2015Jan 18 2016In the first part of this paper I shall discuss the round-about way of how the integrable chiral Potts model was discovered about 30 years ago. As there should be more higher-genus models to be discovered, this might be of interest. In the second part ... More
On pseudo B-Weyl operators and generalized Drazin invertibility for operator matricesMar 23 2015We introduce a new class which generalizes the class of B-Weyl operators. We say that $T\in L(X)$ is pseudo B-Weyl if $T=T_1\oplus T_2$ where $T_1$ is a Weyl operator and $T_2$ is a quasi-nilpotent operator. We show that the corresponding pseudo B-Weyl ... More
Series Prediction based on Algebraic ApproximantsJul 12 2011It is described how the Hermite-Pad\'e polynomials corresponding to an algebraic approximant for a power series may be used to predict coefficients of the power series that have not been used to compute the Hermite-Pad\'e polynomials. A recursive algorithm ... More
Quantum-coherence-enhanced subradiance in a chiral-coupled atomic chainMar 13 2019We theoretically study the quantum-coherence-enhanced subradiance in a chiral-coupled atomic chain with nonreciprocal decay channels. The collective radiation in this one-dimensional (1D) nanophotonics system results from the resonant dipole-dipole interactions ... More
The System of Multi Color-flux-tubes in the Dual Ginzburg-Landau TheoryFeb 27 1996We study the system of multi color-flux-tubes in terms of the dual Ginzburg -Landau theory. We consider two ideal cases, where the directions of all the color-flux-tubes are the same in one case and alternative in the other case for neighboring flux-tubes. ... More
Feynman graphs for non-Gaussian measuresJan 12 2005Nov 30 2006Partition- and moment functions for a general (not necessarily Gaussian) functional measure that is perturbed by a Gibbs factor are calculated using generalized Feynman graphs. From the graphical calculus, a new notion of Wick ordering arises, that coincides ... More
Feynman graph representation of the perturbation series for general functional measuresAug 20 2004A representation of the perturbation series of a general functional measure is given in terms of generalized Feynman graphs and -rules. The graphical calculus is applied to certain functional measures of L\'evy type. A graphical notion of Wick ordering ... More
Asymptotic Analysis of High-Contrast Phononic Crystals and a Criterion for the Band-Gap OpeningSep 30 2006We investigate the band-gap structure of the frequency spectrum for elastic waves in a high-contrast, two-component periodic elastic medium. We consider two-dimensional phononic crystals consisting of a background medium which is perforated by an array ... More
Neutron-Deuteron System and Photon Polarization Parameter at Thermal Neutron EnergiesApr 28 2007Effective Field Theory(EFT) is, the unique, model independent and systematic low-energy version of QCD for processes involving momenta below the pion mass. A low-energy photo-nuclear observable in three-body systems, photon polarization parameter at thermal ... More
Application of EFT at Thermal EnergiesAug 14 2009We have been evaluated some observables of n-d systems by using pionless Effective Field Theory(\EFTNoPion) and insertion of the three-body force up to next-to-next to leading order(N$^2$LO). The evaluated data has been compared with experimental and ... More