55,689 research outputs found

    Does a thin foreign exchange market lead to destabilizing capital-market speculation in the Asian Crisis countries?

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    The authors investigate how the thinness of foreign-exchange markets causes destabilization speculation, especially when exchange-rate flexibility is increased, as it has been in the countries involved in the Asian crisis. They analyze the impact of this market thinness on the dynamic capital mobility and capital market risk of four countries involved in the Asian crisis: Indonesia, the Republic of Korea, Malaysia, and Thailand. Using the vector-autoregression model, impulse response functions, and variance decomposition, they show that in response to one-standard-deviation shock to interest and exchange rates, the dynamic capital mobility of all four countries decreases in the short run. These shocks also cause the capital market risk of these countries to rise. Since the onset of the Asian crisis, the countries involved responded by raising their interest rates and devaluing their currencies. These measures were intended to stem capital flight from the borrowing countries and to encourage capital inflows. But in an environment of protracted financial sector reform and thin foreign exchange markets, these standard policies did not stabilize capital inflows into these countries. The authors'research supports the view that because standard policies were unable to change institutional investors'(self-fulfilling) expectations and herding behavior, the countries'policies have, in the short run, not been successful. This failure is in large part attributable to the very thin foreign exchange markets in these Asian countries.Fiscal&Monetary Policy,Banks&Banking Reform,Payment Systems&Infrastructure,Economic Theory&Research,Capital Markets and Capital Flows,Banks&Banking Reform,Economic Theory&Research,Macroeconomic Management,International Terrorism&Counterterrorism,Insurance&Risk Mitigation

    Random-phase-approximation-based correlation energy functionals: Benchmark results for atoms

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    The random phase approximation (RPA) for the correlation energy functional of density functional theory has recently attracted renewed interest. Formulated in terms of the Kohn-Sham (KS) orbitals and eigenvalues, it promises to resolve some of the fundamental limitations of the local density and generalized gradient approximations, as for instance their inability to account for dispersion forces. First results for atoms, however, indicate that the RPA overestimates correlation effects as much as the orbital-dependent functional obtained by a second order perturbation expansion on the basis of the KS Hamiltonian. In this contribution, three simple extensions of the RPA are examined, (a) its augmentation by an LDA for short-range correlation, (b) its combination with the second order exchange term, and (c) its combination with a partial resummation of the perturbation series including the second order exchange. It is found that the ground state and correlation energies as well as the ionization potentials resulting from the extensions (a) and (c) for closed sub-shell atoms are clearly superior to those obtained with the unmodified RPA. Quite some effort is made to ensure highly converged RPA data, so that the results may serve as benchmark data. The numerical techniques developed in this context, in particular for the inherent frequency integration, should also be useful for applications of RPA-type functionals to more complex systems.Comment: 11 pages, 7 figure

    Discovery Reach of Charged MSSM Higgs Bosons at CMS

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    We review the 5 sigma discovery contours for the charged MSSM Higgs boson at the CMS experiment with 30/fb for the two cases M_H+ m_t. In order to analyze the search reach we combine the latest results for the CMS experimental sensitivities based on full simulation studies with state-of-the-art theoretical predictions of MSSM Higgs-boson production and decay properties. Special emphasis is put on the SUSY parameter dependence of the 5 sigma contours. The variation of ÎĽ\mu can shift the prospective discovery reach in tan_beta by up to Delta tan_beta = 40.Comment: 3 pages, 2 figures, talk given at SUSY08, Seoul, Kore

    Hexagonal SU(3) Unification and its Manifestation at the TeV Scale

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    We consider SU(3)C×SU(2)AL×SU(2)BL×U(1)YSU(3)_{C}\times SU(2)_{AL}\times SU(2)_{BL}\times U(1)_{Y} as the low-energy subgroup of supersymmetric SU(3)6SU(3)^{6} unification. This may imply small deviations from quark-lepton universality at the TeV scale, as allowed by neutron-decay data. New particles are predicted with specific properties. We discuss in particular the new heavy gauge bosons corresponding to SU(2)AL×SU(2)BL→SU(2)LSU(2)_{AL} \times SU(2)_{BL} \to SU(2)_L

    Spin-Orbit Coupling and Tunneling Current in a Parabolic Quantum Dot

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    We propose a novel approach to explore the properties of a quantum dot in the presence of the spin-orbit interaction and in a tilted magnetic field. The spin-orbit coupling within the quantum dot manifest itself as anti-crossing of the energy levels when the tilt angle is varied. The anti-crossing gap has a non-monotonic dependence on the magnitude of the magnetic field and exhibits a peak at some finite values of the magnetic field. From the dependence of the tunneling current through the quantum dot on the bias voltage and the tilt angle, the anti-crossing gap and most importantly the spin-orbit strength can be uniquely determined

    Flavor symmetry breaking effects on SU(3) Skyrmion

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    We study the massive SU(3) Skyrmion model to investigate the flavor symmetry breaking (FSB) effects on the static properties of the strange baryons in the framework of the rigid rotator quantization scheme combined with the improved Dirac quantization one. Both the chiral symmetry breaking pion mass and FSB kinetic terms are shown to improve cc the ratio of the strange-light to light-light interaction strengths and cˉ\bar{c} that of the strange-strange to light-light.Comment: 12 pages, latex, no figure

    Effect of nonlocal interactions on the disorder-induced zero-bias anomaly in the Anderson-Hubbard model

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    To expand the framework available for interpreting experiments on disordered strongly correlated systems, and in particular to explore further the strong-coupling zero-bias anomaly found in the Anderson-Hubbard model, we ask how this anomaly responds to the addition of nonlocal electron-electron interactions. We use exact diagonalization to calculate the single-particle density of states of the extended Anderson-Hubbard model. We find that for weak nonlocal interactions the form of the zero-bias anomaly is qualitatively unchanged. The energy scale of the anomaly continues to be set by an effective hopping amplitude renormalized by the nonlocal interaction. At larger values of the nonlocal interaction strength, however, hopping ceases to be a relevant energy scale and higher energy features associated with charge correlations dominate the density of states.Comment: 9 pages, 7 figure

    Re-embedding a 1-Plane Graph into a Straight-line Drawing in Linear Time

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    Thomassen characterized some 1-plane embedding as the forbidden configuration such that a given 1-plane embedding of a graph is drawable in straight-lines if and only if it does not contain the configuration [C. Thomassen, Rectilinear drawings of graphs, J. Graph Theory, 10(3), 335-341, 1988]. In this paper, we characterize some 1-plane embedding as the forbidden configuration such that a given 1-plane embedding of a graph can be re-embedded into a straight-line drawable 1-plane embedding of the same graph if and only if it does not contain the configuration. Re-embedding of a 1-plane embedding preserves the same set of pairs of crossing edges. We give a linear-time algorithm for finding a straight-line drawable 1-plane re-embedding or the forbidden configuration.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016). This is an extended abstract. For a full version of this paper, see Hong S-H, Nagamochi H.: Re-embedding a 1-Plane Graph into a Straight-line Drawing in Linear Time, Technical Report TR 2016-002, Department of Applied Mathematics and Physics, Kyoto University (2016

    The Optimal Inhomogeneity for Superconductivity: Finite Size Studies

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    We report the results of exact diagonalization studies of Hubbard models on a 4×44\times 4 square lattice with periodic boundary conditions and various degrees and patterns of inhomogeneity, which are represented by inequivalent hopping integrals tt and t′t^{\prime}. We focus primarily on two patterns, the checkerboard and the striped cases, for a large range of values of the on-site repulsion UU and doped hole concentration, xx. We present evidence that superconductivity is strongest for UU of order the bandwidth, and intermediate inhomogeneity, 0<t′<t0 <t^\prime< t. The maximum value of the ``pair-binding energy'' we have found with purely repulsive interactions is Δpb=0.32t\Delta_{pb} = 0.32t for the checkerboard Hubbard model with U=8tU=8t and t′=0.5tt^\prime = 0.5t. Moreover, for near optimal values, our results are insensitive to changes in boundary conditions, suggesting that the correlation length is sufficiently short that finite size effects are already unimportant.Comment: 8 pages, 9 figures; minor revisions; more references adde
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