Investigating effects of oil price changes on the US, the UK and Japan

Based on the structural VAR model of the global crude oil market proposed by Kilian(2009), this article investigates the causes for wild fluctuations in oil prices since the mid-2000s. A main contribution of the study is to compare the effects of changes in oil price on three major economies, the US, the UK, and Japan. I find oil-specific demand shocks as well as aggregate demand shocks played an important role in the rise in the real price of oil since early 2002 and the subsequent sharp drops after the failure of Lehman Brothers Holdings Inc.. Moreover I have found that oil-specific demand shocks increase real GDP in Japan, which is very different from the US and the UK where oil-specific demand shocks lead to reduction in real GDP. This difference possibly comes from the oil efficiency of Japanese products.SVAR,Oil price

Theory of proximity effect in ferromagnet/superconductor heterostructures in the presence of spin dependent interfacial phase shift

We study the proximity effect and charge transport in ferromagnet (F)/superconductor (S) and S/F/I/F/S junctions (where I is insulator) by taking into account simultaneously exchange field in F and spin-dependent interfacial phase shifts (SDIPS) at the F/S interface. We solve the Usadel equations using extended Kupriyanov–Lukichev boundary conditions which include SDIPS, where spin-independent part of tunneling conductance GT and spin-dependent one Gφ coexist. The resulting local density of states (LDOS) in a ferromagnet depends both on the exchange energy Eex and Gφ/GT. We show that the magnitude of zero-temperature gap and the height of zero-energy LDOS have a non-monotonic dependence on Gφ/GT. We also calculate Josephson current in S/F/I/F/S junctions and show that crossover from 0-state to

Strong evidence for the three-dimensional Fermi liquid behaviour of quasiparticles in high-TCT_{\rm C} cupurates

It is generally believed that behaviours of quasiparticles (holes) in high-$T_{\rm C}$ cupurates should be attributed to the two-dimensional (2D) electronic states in the CuO$_{2}$ planes. The various anomalies of the transport coefficients for temperatures above $T_{\rm C}$ are long-standing insoluble puzzles and cause serious controversy. Here we reanalyse the published experimental date of LSCO cupurates. We find that the normal-state susceptibility, resistivity, Hall coefficient etc vary precisely as $T^{2}\ln T$ as a function of temperature $T$ in agreement with the prediction of the Fermi liquid model. The quasiparticles are shown to definitely behave as a 3D Fermi liquid. Various attempts to describe the system in terms of non-Fermi liquids,e.g. the RVB state, seem to be erroneous.Comment: 2 pages, 3 Postscript figures, To appear in Physica

On the accuracy of the numerical integrals of the newmark’s method for computing inelastic seismic response

The paper proposes an algorithm of the numerical integration with the modal analysis for computing inelastic seismic responses, and furthermore, the accuracy of the numerical integration with the Newmark’s =1/4 method that is most popular in the earthquake engineering is discussed by comparing with the response computed by the proposed method

Weber's class number problem and its variants

We survey Weber's class number problem and its variants in the spirit of arithmetic topology; we recollect some history, present a relation to certain units and generalized Pell's equation, and overview a study of the $p$-adic limits of class numbers in $\mathbb{Z}_p$-towers together with numerical investigation for knots and elliptic curves

Generalized Pell's equations and Weber's class number problem

We study a generalization of Pell's equation, whose coefficients are certain algebraic integers. Let $X_0=0$ and $X_n=\sqrt{2+X_{n-1}}$ for each $n\in \mathbb{Z}_{\ge 1}$. We study the $\mathbb{Z}[X_{n-1}]$-solutions of the equation $x^2-X_n^2y^2=1$. By imitating the solution to the classical Pell's equation, we introduce new continued fraction expansions for $X_n$ over $\mathbb{Z}[X_{n-1}]$ and obtain an explicit solution of the generalized Pell's equation. In addition, we show that our explicit solution generates all the solutions if and only if the answer to Weber's class number problem is affirmative. We also obtain a congruence relation for the ratios of the class numbers of the $\mathbb{Z}_2$-extension over the rationals and show the convergence of the class numbers in $\mathbb{Z}_2$.Comment: 17 page