8,337 research outputs found
Yangian Symmetry, S-Matrices and Bethe Ansatz for the AdS5 x S5 Superstring
We discuss the relation between the recently derived bound state S-matrices
for the AdS5 x S5 superstring and Yangian symmetry. We will study the relation
between this Yangian symmetry and the Bethe ansatz. In particular we can use it
to derive the Bethe equations for bound states.Comment: Proceedings of the work presented at the 4-th EU RTN Workshop in
Varna, Bulgari
Bound States, Yangian Symmetry and Classical r-matrix for the AdS5 x S5 Superstring
We show that the recently found S-matrices describing the scattering of
two-particle bound states of the light-cone string sigma model on AdS5 x S5 are
compatible with Yangian symmetry. In case the invariance with respect to the
centrally extended su(2|2) algebra is not sufficient to fully specify the
scattering matrix, the requirement of Yangian symmetry provides an alternative
to the Yang-Baxter equation and leads to a complete, up to an overall phase,
determination of the S-matrix. We then compare the semi-classical limit of the
bound state S-matrices with the universal classical r-matrix by Beisert and
Spill evaluated in the corresponding bound state representations and find
perfect agreement.Comment: V3: Published version, reference adde
Biolegality: How Biology and Law Redefine Sociality
As an empirical concept, biolegality emerged at the height of biotechnological advances in Euro-American societies when rapid changes in the life sciences (including molecular biology, immunology, and the neurosciences) and their attendant techniques (including reproductive technologies and gene editing) started to challenge ethical norms, legal decisions, and legal forms. As a theoretical concept, biolegality deepens the Foucauldian notion of biopolitics with an operation of legality that emphasizes how biology and its attendant technologies alter legal form, knowledge, practice, and experience. These empirical and theoretical developments affect how we understand sociality. While public discourse remains preoccupied with the call for more regulation mdash thereby underscoring law's lag in its dealings with technology mdash the social science scholarship describes instead how bioscience and biotechnology are fragmenting and rearranging legal knowledge about property, personhood, parenthood, and collective identity. As it opens broader anthropological debates around exchange, self, kinship, and community, the study of biolegality brings a novel currency to the discipline, addressing how biology and law inform new ways of relating and knowing
Bound States of the q-Deformed AdS5 x S5 Superstring S-matrix
The investigation of the q deformation of the S-matrix for excitations on the
string world sheet in AdS5 x S5 is continued. We argue that due to the lack of
Lorentz invariance the situation is more subtle than in a relativistic theory
in that the nature of bound states depends on their momentum. At low enough
momentum |p|<E the bound states transform in the anti-symmetric representation
of the super-algebra symmetry and become the solitons of the Pohlmeyer reduced
theory in the relativistic limit. At a critical momentum |p|=E they become
marginally unstable, and at higher momenta the stable bound states are in the
symmetric representation and become the familiar magnons in the string limit as
q->1. This subtlety fixes a problem involving the consistency of crossing
symmetry with the relativistic limit found in earlier work. With mirror
kinematics, obtained after a double Wick rotation, the bound state structure is
simpler and there are no marginally unstable bound states.Comment: 25 page
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Evaluation of ERA-Interim reanalysis precipitation products using England and Wales observations
Precipitation forecast data from the ERA-Interim reanalysis (33 years) are evaluated using the daily England and Wales Precipitation (EWP) observations obtained from a rain gauge network. Observed and reanalysis daily precipitation data are both described well by Weibull distributions with indistinguishable shapes but different scale parameters, such that the reanalysis underestimates the observations by an average factor of 22%. The correlation between the observed and ERA-Interim time series of regional, daily precipitation is 0.91. ERA-Interim also captures the statistics of extreme precipitation including a slightly lower likelihood of the heaviest precipitation events (>15 mm day− 1 for the regional average) than indicated by the Weibull fit. ERA-Interim is also closer to EWP for the high precipitation events. Since these carry weight in longer accumulations, a smaller underestimation of 19% is found for monthly mean precipitation. The partition between convective and stratiform precipitation in the ERA-Interim forecast is also examined. In summer both components contribute equally to the total precipitation amount, while in winter the stratiform precipitation is approximately double convective. These results are expected to be relevant to other regions with low orography on the coast of a continent at the downstream end of mid-latitude stormtracks
Mechanisms of CO2 Capture in Ionic Liquids: A Computational Perspective
We present computational studies of CO2 sorption in two different classes of ionic liquid. The addition of carbon dioxide to four superbase ionic liquids, [P3333][Benzim], [P3333][124Triz], [P3333][123Triz] and [P3333][Bentriz] was studied using DFT approach and considering anions alone and individual ion pairs. Addition of CO2 to the anion alone clearly resulted in the formation of a covalently-bound carbamate function with the strength of binding correlated to experimental capacity. In the ion pair however the cation significantly alters the nature of the bonding such that the overall cohesive energy is reduced. Formation of a strong carbamate function occurs at the expense of weakening the interaction between anion and cation. In [N111][L-ALA], a representative amino acid ionic liquid, evidence was found for a low-enegy monomolecular mechanism for carbamate formation, explaining the 1:1 molar uptake ratio observed in some amino acid ionic liquids. The mechanism involves proton transfer to to the carboxylate group of the aminate anion
Grid computing and molecular simulations: the vision of the eMinerals Project
This paper discusses a number of aspects of using grid computing methods in support of molecular simulations, with examples drawn from the eMinerals project. A number of components for a useful grid infrastructure are discussed, including the integration of compute and data grids, automatic metadata capture from simulation studies, interoperability of data between simulation codes, management of data and data accessibility, management of jobs and workflow, and tools to support collaboration. Use of a grid infrastructure also brings certain challenges, which are discussed. These include making use of boundless computing resources, the necessary changes, and the need to be able to manage experimentation
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