Z_{12-I} Orbifold Compactification toward SUSY Standard Model

We explain the orbifold compactification in string models and present a Z_{12-I} orbifold compactification toward supersymmetric standard models. We also point out an effective R-parity from this string construction. The VEVs of gauge singlets are chosen such that phenomenological constraints are satisfied.Comment: 13 pages with 5 figure. Talk presented at "CTP Symposium on SUSY at LHC", Cairo, 11-14 March 200

Scalable Task-Based Algorithm for Multiplication of Block-Rank-Sparse Matrices

A task-based formulation of Scalable Universal Matrix Multiplication Algorithm (SUMMA), a popular algorithm for matrix multiplication (MM), is applied to the multiplication of hierarchy-free, rank-structured matrices that appear in the domain of quantum chemistry (QC). The novel features of our formulation are: (1) concurrent scheduling of multiple SUMMA iterations, and (2) fine-grained task-based composition. These features make it tolerant of the load imbalance due to the irregular matrix structure and eliminate all artifactual sources of global synchronization.Scalability of iterative computation of square-root inverse of block-rank-sparse QC matrices is demonstrated; for full-rank (dense) matrices the performance of our SUMMA formulation usually exceeds that of the state-of-the-art dense MM implementations (ScaLAPACK and Cyclops Tensor Framework).Comment: 8 pages, 6 figures, accepted to IA3 2015. arXiv admin note: text overlap with arXiv:1504.0504

Supersymmetric three family chiral SU(6) grand unification model from F-theory

We obtain a supersymmetric three family chiral SU(6) grand unification model with the global family symmetry SU(3)[family] from F-theory. This model has nice features such as all the fermion masses are reasonably generated and there results only one pair of Higgs doublets, realizing the doublet-triplet splitting from the family symmetry SU(3)[family]. The proton hexality is realized toward the proton stability problem. There is a room to fit the three gauge couplings using the F-theory flux idea and we obtain the proton lifetime in the 10^{36-37} yr region.Comment: 5 pages, to be published in Phys. Rev.

Genetic Contamination of Traditional Products

Cross-pollination can be caused by birds, insects and wind. Genetically modified (GM) seeds are produced each year in a controlled environment to maintain their purity. However, pollen from the GM crop can be transferred to traditional crops. When the GM crop producers are in long-run equilibrium and buy seeds from a monopolistic seed producer, the resulting market equilibrium is identical to that when a seed monopolist produces the GM crop directly. When involuntary genetic contamination occurs, the monopolist eventually loses its advantage and stops its protection of GM seeds. A terminator gene can stop genetic contamination but imposes spillover costs on the traditional producers and reduces their outputs.genetic contamination

Cosmological constant is probably adjustable in brane worlds

In the brane world scenario, possessing the self-tuning property of the cosmological constant, we study the probability amplitude for an initial state of the Universe to transform to final states with some curvatures. In the Kim, Kyae and Lee model, there exists a finite range of parameters such that the transition amplitude to a near flat universe is exponentially dominated by the smallness of curvature, > e^{positive number}/{Lambda-bar}^2}, i.e. is dominated by an almost flat universe of |Lambda-bar|<epsilon.Comment: 6 pages with 2 figure

Dynamic transition and Shapiro-step melting in a frustrated Josephson-junction array

We consider a two-dimensional fully frustrated Josephson-junction array driven by combined direct and alternating currents. Interplay between the mode locking phenomenon, manifested by giant Shapiro steps in the current-voltage characteristics, and the dynamic phase transition is investigated at finite temperatures. Melting of Shapiro steps due to thermal fluctuations is shown to be accompanied by the dynamic phase transition, the universality class of which is also discussed

Charmonium levels near threshold and the narrow state X(3872) \to \pi^{+}\pi^{-}\jpsi

We explore the influence of open-charm channels on charmonium properties, and profile the 1:3D2, 1:3D3 and 2:1P1 charmonium candidates for X(3872). The favored candidates, the 1:3D2 and 1:3D3 levels, both have prominent radiative decays. The 1:3D2 might be visible in the $D^{0}\bar{D}^{*0}$ channel, while the dominant decay of the 1:3D3 state should be into $D\bar{D}$. We propose that additional discrete charmonium levels can be discovered as narrow resonances of charmed and anticharmed mesons.Comment: 8 pages, 6 figures, uses RevTeX and boxedeps; few transcription errors corrected in Tables IV and VI, three entries added in Table V, updated references. Version to appear in Phys. Rev.

REGULATION OF NITROGEN POLLUTION: TAXES VERSUS QUOTAS

This paper investigates the effects of first-best policies to regulate nitrogen application. Some nitrogen fertilizer is applied ex ante before a random rainfall, but sidedressed nitrogen may be applied ex post. First-best policy is a tax or a quota on ex ante application, because sidedressed nitrogen is not leached. Since a risk-averse farmer uses more nitrogen ex ante than a risk-neutral farmer, a higher tax must be imposed on the former. Action equivalent first-best taxes and quotas are also welfare equivalent. An empirical model for wheat in Israel was used to demonstrate the analytical findings.Environmental Economics and Policy,

Breaks in the Chain of Comparative Advantage

chain; comparative advantage

Variation in Boilerplate: Rational Design or Random Mutation?

Standard contract doctrine presumes that sophisticated parties choose their terminology carefully because they want courts or counterparts to understand what they intended. The implication of this “Rational Design” model of rational behavior is that courts should pay careful attention to the precise phrasing of contracts. Using a study of the sovereign bond market, we examine the Rational Design model as applied to standard-form contracting. In NML v. Argentina, federal courts in New York attached importance to the precise phrasing of the boilerplate contracts at issue. The industry promptly condemned the decision for a supposedly erroneous interpretation of a variant of a hoary boilerplate clause. Utilizing data on how contracting practices responded to the decision, we ask whether the market response indicates that parties in fact intended for the small variations in their contract language to embody a particular meaning. We find the data supports a model closer to random mutation rather than rational design