Aspects of warm-flat directions

Considering the mechanism of dissipative slow-roll that has been used in warm inflation scenario, we show that dissipation may alter usual cosmological scenarios associated with SUSY-flat directions. We mainly consider SUSY-flat directions that have strong interactions with non-flat directions and may cause strong dissipation both in thermal and non-thermal backgrounds. An example is the Affleck-Dine mechanism in which dissipation may create significant (both qualitative and quantitative) discrepancies between the conventional scenario and the dissipative one. We also discuss several mechanisms of generating curvature perturbations in which the dissipative field, which is distinguished from the inflaton field, can be used as the source of cosmological perturbations. Considering the Morikawa-Sasaki dissipative coefficient, the damping caused by the dissipation may be significant for many MSSM flat directions even if the dissipation is far from thermal equilibrium.Comment: 22 pages, accepted for publication in International Journal of Modern Physics

Can The Majorana neutrino CP-violating phases be restricted ?

We reanalyze the constraints in neutrino masses and MNS lepton mixing parameters using the new data from the terrestrial (KamLAND) and astrophysical (WMAP) observations together with the HEIDELBERG-MOSCOW double beta decay experiment. It leads us to the almost degenerate or inverse hierarchy neutrino mass scenario. We discuss the possibility of getting the bound for the Majorana CP violating phase.Comment: 6 pages, 2 figure

Elliptic Inflation: Generating the curvature perturbation without slow-roll

There are many inflationary models in which inflaton field does not satisfy the slow-roll condition. However, in such models, it is always difficult to generate the curvature perturbation during inflation. Thus, to generate the curvature perturbation, one must introduce another component to the theory. To cite a case, curvatons may generate dominant part of the curvature perturbation after inflation. However, we have a question whether it is unrealistic to consider the generation of the curvature perturbation during inflation without slow-roll. Assuming multi-field inflation, we encounter the generation of the curvature perturbation during inflation without slow-roll. The potential along equipotential surface is flat by definition and thus we do not have to worry about symmetry. We also discuss about KKLT models, in which corrections lifting the inflationary direction may not become a serious problem if there is a symmetry enhancement at the tip (not at the moving brane) of the inflationary throat.Comment: 27pages, 8figures, to appear in JCA

The Structural Change in the Supply Chain of Oil Palm – A Case of North Sumatra Province, Indonesia

In this paper, we analyze the structural change in the supply chain of oil palm in North Sumatra, Indonesia, especially after the financial crisis of the late 20th century. We first describe the past and present market structure and conduct of oil palm industries in North Sumatra with an industrial organization approach based on our field study. The analysis reveals that the supply chain of oil palm in North Sumatra has changed such that farmers had more power to determine FFB prices over crushing companies, especially from 2001 through 2004. However, farmers lost bargaining power during 2007-2008 due to a decrease in palm oil demand, plunging of palm oil prices, and a regulation imposed upon crushing companies by the Ministry of Agriculture. To analyze such structural changes empirically, we test the existence of Asymmetric Price Transmission (APT), in which the speed of adjustments of the output price after the input price increases or decreases is different; the existence of APT implies the existence of market power. We apply the (Momentum) Threshold Autoregressive ((M-)TAR) model to estimate APT. According to the estimation results, crushing companies had more power to determine FFB prices over farmers until around March 2002. This situation changed such that farmers had more bargaining power from around April 2002 to around April 2007 before the power became balanced. The structural change test also shows these time points as optimal structural change points. The APT estimation, however, has little rigorous theoretical background, and the concept of APT is not necessarily related to market power. Hence, we next analyze the market power of crushers and farmers both theoretically and empirically. The estimation result of market power indicates that the farmers had no market power before the third quarter of 2002, but they did have market power from the next quarter to the first quarter of 2008, after which time they again lose market power. These empirical results are consistent both with each other and with the descriptions of the structural change. Finally, we conclude and draw some implications for farmers, crushers, and consumers of palm oil.Indonesian palm oil, market power, Asymmetric Price Transmission (APT), (Momentum) Threshold Autoregressive ((M-)TAR) model., Agribusiness, Agricultural and Food Policy, Community/Rural/Urban Development, Food Consumption/Nutrition/Food Safety, Labor and Human Capital,

Observation of a half step magnetization in the {Cu-3}-type triangular spin ring

We report pulsed field magnetization and ESR experiments on a {Cu-3} nanomagnet, where antiferromagnetically coupled Cu2+ (S=1/2) ions form a slightly distorted triangle. The remarkable feature is the observation of a half step magnetization, hysteresis loops, and an asymmetric magnetization between a positive and a negative field in a fast sweeping external field. This is attributed to an adiabatic change of magnetization. The energy levels determined by ESR unveil that the different mixing nature of a spin chirality of a total S=1/2 Kramers doublet by virtue of Dzyaloshinskii-Moriya interactions is decisive for inducing half step magnetization.</p

HH-TT phase diagram of solid oxygen

Comprehensive magnetic-field-temperature ($H$-$T$) phase diagram of solid oxygen including the $\theta$ phase is discussed in the context of the ultrahigh-field measurement and the magnetocaloric effect (MCE) measurement. The problems originating from the short duration of the pulse field, non-equilibrium condition and MCEs, are pointed out and dealt with. The obtained phase diagram manifests the entropy relation between the phases as $S_\theta \sim S_\alpha<S_\beta<<S_\gamma$.Comment: 5 pages, 5 figure