73,069 research outputs found
Beware of Courts Bearing Gifts: Transparency and the Court of Justice of the European Union
This article reconsiders the principle of transparency in the European Union (EU) legal order and takes as its focal point the contribution of the EU Courts as regards the presumptions of non-disclosure of EU documents. The aim is to investigate the role played by the judiciary in relation to a twofold question: How open can the Union’s decision-making be, and is it possible for citizens to participate in the decision-making process of EU institutions, bodies, offices and agencies? The article argues that accountability deficits in the field of access to documents have been filled, to an extent, by the EU Courts’ imposition of boundaries on the broad derogations to the right of access to documents. But nevertheless, the article concludes that the establishment through the case law of general presumptions against openness has fundamentally weakened the standards of accountability. Rather regrettably, although the EU legislature set the default position to the widest access to documents, this has been reversed to non-disclosure by the EU judiciary as regards non-legislative documents
Superstring dualities and p-brane bound states
We show that the M-theory/IIA and IIA/IIB superstring dualities together with
the diffeomorphism invariance of the underlying theories require the presence
of certain p-brane bound states in IIA and IIB superstring theories preserving
1/2 of the spacetime supersymmetry. We then confirm the existence of IIA and
IIB supergravity solutions having the appropriate p-brane bound states
interpretation.Comment: 21 pages, Phyzzx, Minor corrections, Version that will appear in
Nucl. Phys.
Coleman meets Schwinger
It is well known that spherical D-branes are nucleated in the presence of an
external RR electric field. Using the description of D-branes as solitons of
the tachyon field on non-BPS D-branes, we show that the brane nucleation
process can be seen as the decay of the tachyon false vacuum. This process can
describe the decay of flux-branes in string theory or the decay of quintessence
potentials arising in flux compactifications.Comment: 5 pages, 2 figure
Critical Behavior of a Three-State Potts Model on a Voronoi Lattice
We use the single-histogram technique to study the critical behavior of the
three-state Potts model on a (random) Voronoi-Delaunay lattice with size
ranging from 250 to 8000 sites. We consider the effect of an exponential decay
of the interactions with the distance,, with , and
observe that this system seems to have critical exponents and
which are different from the respective exponents of the three-state Potts
model on a regular square lattice. However, the ratio remains
essentially the same. We find numerical evidences (although not conclusive, due
to the small range of system size) that the specific heat on this random system
behaves as a power-law for and as a logarithmic divergence for
and Comment: 3 pages, 5 figure
Graphene-based spin-pumping transistor
We demonstrate with a fully quantum-mechanical approach that graphene can
function as gate-controllable transistors for pumped spin currents, i.e., a
stream of angular momentum induced by the precession of adjacent
magnetizations, which exists in the absence of net charge currents.
Furthermore, we propose as a proof of concept how these spin currents can be
modulated by an electrostatic gate. Because our proposal involves nano-sized
systems that function with very high speeds and in the absence of any applied
bias, it is potentially useful for the development of transistors capable of
combining large processing speeds, enhanced integration and extremely low power
consumption
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