Deuteron form factors in chiral effective theory: regulator-independent results and the role of two-pion exchange

We evaluate the deuteron charge, quadrupole, and magnetic form factors using wave functions obtained from chiral effective theory ($\chi$ET) when the potential includes one-pion exchange, chiral two-pion exchange, and genuine contact interactions. We study the manner in which the results for form factors behave as the regulator is removed from the $\chi$ET calculation, and compare co-ordinate- and momentum-space approaches. We show that, for both the LO and NNLO chiral potential, results obtained by imposing boundary conditions in co-ordinate space at $r=0$ are equivalent to the $\Lambda \to \infty$ limit of momentum-space calculations. The regulator-independent predictions for deuteron form factors that result from taking the $\Lambda \to \infty$ limit using the LO $\chi$ET potential are in reasonable agreement with data up to momentum transfers of order 600 MeV, provided that phenomenological information for nucleon structure is employed. In this range the use of the NNLO $\chi$ET potential results in only small changes to the LO predictions, and it improves the description of the zero of the charge form factor

Italo Calvino and the organizational imagination: Reading social organization through urban metaphors

© 2014 Taylor & Francis. This article explores the way in which uses or abuses of urban metaphors can inform differing polities and ethics of human organization. From its earliest inception, the city has taken on a metaphorical significance for human communities; being, at one and the same time, a discursive textual product of culture and, reciprocally, a provider of artefacts and architecture that produces culture and meaning. The city can be interpreted as a trope that operates bidirectionally in cultural terms. It is a sign that can be worked to serve the principles of both metonymy and synecdoche. In metonymical or reductive form, the city has the propensity to become weighty and deadening. The work of Michael Porter on competitive strategy is invoked to illustrate this effect. In the guise of synecdoche, on the other hand, the city offers imaginative potential. Drawing inspiration from the literary works of Italo Calvino (in particular, his novel Invisible Cities), the article attempts to reveal the fecundity of the city for interpreting technologically mediated organizational life. Calvino's emphasis on the principle of ‘lightness’ provides a link to the social theoretical writing of Boltanski and Chiapello on the ‘projective city’. A synthesis of these two stylistically different literatures yields a novel way of critically approaching and understanding the reticular form and emerging ethics of contemporary human organization