The Expanding Zoo of Calabi-Yau Threefolds

This is a short review of recent constructions of new Calabi-Yau threefolds with small Hodge numbers and/or non-trivial fundamental group, which are of particular interest for model-building in the context of heterotic string theory. The two main tools are topological transitions and taking quotients by actions of discrete groups. Both of these techniques can produce new manifolds from existing ones, and they have been used to bring many new specimens to the previously sparse corner of the Calabi-Yau zoo where both Hodge numbers are small. Two new manifolds are also obtained here from hyperconifold transitions, including the first example with fundamental group S3, the smallest non-Abelian group.Comment: 24 pages, PDFLaTeX. To be published in the special issue "Computational Algebraic Geometry in String and Gauge Theory" of Advances in High Energy Physics. v2: Added reference, and data for four new manifolds constructed therei

Weird counsels: the critic and the critics

No abstract available

Hyperconifold Transitions, Mirror Symmetry, and String Theory

Multiply-connected Calabi-Yau threefolds are of particular interest for both string theorists and mathematicians. Recently it was pointed out that one of the generic degenerations of these spaces (occurring at codimension one in moduli space) is an isolated singularity which is a finite cyclic quotient of the conifold; these were called hyperconifolds. It was also shown that if the order of the quotient group is even, such singular varieties have projective crepant resolutions, which are therefore smooth Calabi-Yau manifolds. The resulting topological transitions were called hyperconifold transitions, and change the fundamental group as well as the Hodge numbers. Here Batyrev's construction of Calabi-Yau hypersurfaces in toric fourfolds is used to demonstrate that certain compact examples containing the remaining hyperconifolds - the Z_3 and Z_5 cases - also have Calabi-Yau resolutions. The mirrors of the resulting transitions are studied and it is found, surprisingly, that they are ordinary conifold transitions. These are the first examples of conifold transitions with mirrors which are more exotic extremal transitions. The new hyperconifold transitions are also used to construct a small number of new Calabi-Yau manifolds, with small Hodge numbers and fundamental group Z_3 or Z_5. Finally, it is demonstrated that a hyperconifold is a physically sensible background in Type IIB string theory. In analogy to the conifold case, non-perturbative dynamics smooth the physical moduli space, such that hyperconifold transitions correspond to non-singular processes in the full theory.Comment: 23 pages, PDFLaTeX. v2: Abstract and introduction slightly expanded, and examples of new manifolds added. Also added references and hyperref. v3: Minor corrections, including to relations on pg.

Militarising Mumbai? The ‘politics’ of response

This article focuses on how urban security has been governed in Mumbai in the aftermath of the 2008 terrorist attacks (26/11). The event was widely cited as a major turning point in the securitisation and militarisation of Indian cities. It also produced significant political upheaval, which in turn generated calls for a major institutional overhaul of the governmental architecture for handling terrorism. This article takes the political and policy repercussions of 26/11 as an intervention into critical debates about the (para-)militarisation of policing and the politics of urban security. Here I shift the focus from the disciplinary and divisive effects of policies towards an emphasis on their spectacular and theatrical dimensions. If we are to make sense of the ‘militarised’ focus of the policy response to 26/11, I argue, we need to take seriously its populist, aspirational qualities

China and Brazil: Economic impacts of a growing relationship

The paper analyses the economic impacts of China's re-emergence on Brazil, looking at both the direct effects of China on Brazil in terms of bilateral trade and investment flows and the indirect effects through increased competition in export markets for manufactured goods and higher world prices for primary commodities. Despite a surge in Chinese FDI in Brazil in 2010, the main driver of bilateral relations is trade. While bilateral trade has grown rapidly, the pattern that has emerged has given rise to concern because Brazil's exports are concentrated in a small number of primary products while imports from China are almost entirely of manufactured goods that are becoming more technologically sophisticated over time. Brazil has benefitted in the short term from the high prices of primary commodities (partly caused by growing Chinese demand), but has lost export markets to China in manufactures, contributing to the "primarization" of the country's export basket