Electron Spin Resonance in Quasi-One-Dimensional Quantum Antiferromagnets: Relevance of Weak Interchain Interactions

We discuss universal features on the electron spin resonance (ESR) of a temperature-induced Tomonaga-Luttinger liquid phase in a wide class of weakly coupled $S=1/2$ antiferromagnetic spin chains such as spin ladders, spin tubes and three-dimensionally coupled spin chains. We show that the ESR linewidth of various coupled chains increases with lowering temperature while the linewidth of a single spin chain is typically proportional to temperature. This broadening with lowering temperature is attributed to anisotropic interchain interactions and has been indeed observed in several kinds of three-dimensional (3D) magnets of weakly coupled spin chains above the 3D ordering temperature. We demonstrate that our theory can account for anomalous behaviors of the linewidths in an $S=1/2$ four-leg spin tube compound Cu$_2$Cl$_4 \cdot$H$_8$C$_4$SO$_2$ (abbreviated to Sul-Cu$_2$Cl$_4$) and a three-dimensionally coupled $S=1/2$ spin chain compound CuCl$_2\cdot 2$NC$_5$H$_5$

Spring Temperature Predicts the Long-term Molting Phenology of Two Cicadas, Cryptotympana facialis and Graptopsaltria nigrofuscata (Hemiptera: Cicadidae)

To investigate how seasonal insects respond to changing environments, nymphal skins of the two cicadas Cryptotympana facialis (Walker) and Graptopsaltria nigrofuscata (Motschulsky) (Hemiptera: Cicadidae) were monitored weekly from late July to August over 12 yr in a suburban habitat of central Japan. Based on over 8, 000 skins collected from 1995 to 2006, the authors estimated the period during which temperature or precipitation impacted skin abundance and phenology. Adults of C. facialis tended to emerge earlier than those of G. nigrofuscata, for which total skin counts fluctuated up to sevenfold among years. The effective accumulated temperature from the previous 3.0–3.5 mo to the most recent 1.0–1.5 mo at a threshold of approximately >18°C showed the best fit to the cumulative skin counts within a season. Temperature explained 47 and 64% of the total variation in the skin counts for C. facialis and G. nigrofuscata, respectively. The point at which temperature had this effect was consistent between male and female cicadas. Conversely, accumulated precipitation accounted for <16% of the variation in the skin counts for both species. In summary, this long-term study revealed that late-spring temperature plays a key role in predicting the molting phenology of C. facialis and G. nigrofuscata but does not necessarily explain a large amount of the abundance fluctuation

Analysis of Japan\u27s RTA and WTO Dispute Settlement Mechanism

This thesis analyzes Japan’s decision to use Dispute Settlement Mechanisms (DSMs) in trade agreements. International trade rules are effective when properly applied: they prevent abrogation of the obligations that come with membership in international economic organizations. The DSMs are important ways to enforce the international trade commitments agreed upon by signatory countries. To date, member countries have filed more than 500 cases through the World Trade Organization (WTO), effectively enforcing the rules of the largest multilateral trade organization. On the other hand, in Japan\u27s regional trade agreements (RTAs), none of the DSMs have ever been invoked despite the presence of many potential disputes. This paper first looks through the previous literature related to the use/non-use of DSMs. After that it introduces originally collected data on Japan’s DSMs in trade agreements and analyzes which variables affect Japan’s decision to initiate a formal dispute settlement process in the World Trade Organization. It finds that the amount of export, the degree of democracy, and sectoral characteristics positively affect Japan’s decision of using a DSM. On the other hand, Japan’s decision to use or join a DSM is negatively affected by RTA with a disputing country, Southeast Asian category, the number of use times when Japan used DSMs with that disputing country, and even the disputing country’s Gross Domestic Product (GDP) per capita. The results of analysis implies that the Japan is concerned that using a DSM may worsen the relations with a disputing country. I suggest multilateral DSM would be a better option to mitigate Japan’s concerns about using a DSM in its RTAs

Coupled forward-backward trajectory approach for non-equilibrium electron-ion dynamics

We introduce a simple ansatz for the wavefunction of a many-body system based on coupled forward and backward-propagating semiclassical trajectories. This method is primarily aimed at, but not limited to, treating nonequilibrium dynamics in electron-phonon systems. The time-evolution of the system is obtained from the Euler-Lagrange variational principle, and we show that this ansatz yields Ehrenfest mean field theory in the limit that the forward and backward trajectories are orthogonal, and in the limit that they coalesce. We investigate accuracy and performance of this method by simulating electronic relaxation in the spin-boson model and the Holstein model. Although this method involves only pairs of semiclassical trajectories, it shows a substantial improvement over mean field theory, capturing quantum coherence of nuclear dynamics as well as electron-nuclear correlations. This improvement is particularly evident in nonadiabatic systems, where the accuracy of this coupled trajectory method extends well beyond the perturbative electron-phonon coupling regime. This approach thus provides an attractive route forward to the ab-initio description of relaxation processes, such as thermalization, in condensed phase systems