Einstein-Cartan-Dirac gravity with U(1)U(1) symmetry breaking

Einstein-Cartan theory is an extension of the standard formulation of General Relativity where torsion (the antisymmetric part of the affine connection) is non-vanishing. Just as the space-time metric is sourced by the stress-energy tensor of the matter fields, torsion is sourced via the spin density tensor, whose physical effects become relevant at very high spin densities. In this work we introduce an extension of the Einstein-Cartan-Dirac theory with an electromagnetic (Maxwell) contribution minimally coupled to torsion. This contribution breaks the $U(1)$ gauge symmetry, which is suggested by the possibility of a torsion-induced phase transition in the early Universe, yielding new physics in extreme (spin) density regimes. We obtain the generalized gravitational, electromagnetic and fermionic field equations for this theory, estimate the strength of the corrections, and discuss the corresponding phenomenology. In particular, we briefly address some astrophysical considerations regarding the relevance of the effects which might take place inside ultra-dense neutron stars with strong magnetic fields (magnetars).Comment: 15 double column pages; v2: removed one section and added content to other sections. Version accepted for publication on EPJ

Strong consumer data protection can be a disruptive innovation

Apparent consumer disinterest in privacy may result precisely from a lack of options, writes Francisco Costa-Cabra

Does Inflation Targeting Matter for Output Growth? Evidence from Industrial and Emerging Economies

This paper examines the effects of inflation targeting on industrial and emerging economies' output growth over the "globalization years" of 1986-2004. Controlling for trade openness and two indicators of financial globalization, the authors find systematic positive and significant effects of inflation targeting on real output growth. In dynamic models, the findings show strong output persistence in industrial economies, in which partial and full inflation targeting regimes have a positive long-run impact on growth. In emerging markets, only full inflation targeting policies have any output effect in the long-run. The results suggest that strict inflation targeting is needed to make the discipline effect of the disinflation process outweigh the output costs of promoting high interest rates to attract capital flows in a global world. These findings are robust to the treatment of endogenous globalization measures.Economic Growth; Globalization; Inflation Targeting; Panel Data Methods

The euro at twenty : follies of youth?

This paper overviews the early history of the euro and argues that the euro was suboptimally designed, without monetary sovereignty of Eurozone (EZ) Member States, in order to comply with political goals set by wealthier Member States. Given this constraint, the euro architects designed a single currency in which its irreversibility is achieved through the EZ banking system, with recourse to the TARGET2 payment system. This allowed the banking systems of deficit Member States to fund large cumulative current account deficits in the first decade of the euro. The euro crisis led EZ policy makers to define new far more demanding fiscal rules and a new Banking Union to constrain the ability of EZ banking systems to fund sovereigns and current account deficits. Thus, the euro at twenty has become more fragile.info:eu-repo/semantics/publishedVersio