2,745 research outputs found
Curvature function and coarse graining
A classic theorem in the theory of connections on principal fiber bundles
states that the evaluation of all holonomy functions gives enough information
to characterize the bundle structure (among those sharing the same structure
group and base manifold) and the connection up to a bundle equivalence map.
This result and other important properties of holonomy functions has encouraged
their use as the primary ingredient for the construction of families of quantum
gauge theories. However, in these applications often the set of holonomy
functions used is a discrete proper subset of the set of holonomy functions
needed for the characterization theorem to hold. We show that the evaluation of
a discrete set of holonomy functions does not characterize the bundle and does
not constrain the connection modulo gauge appropriately.
We exhibit a discrete set of functions of the connection and prove that in
the abelian case their evaluation characterizes the bundle structure (up to
equivalence), and constrains the connection modulo gauge up to "local details"
ignored when working at a given scale. The main ingredient is the Lie algebra
valued curvature function defined below. It covers the holonomy
function in the sense that .Comment: 34 page
Decolonizing Trauma: A Study of Multidirectional Memory in Zadie Smith’s “The Embassy of Cambodia”
The present article analyses Zadie Smith’s short story “The Embassy of Cambodia” (2013) as a narrative that contributes to the decolonization of trauma studies. In the introduction I will lay out briefly the state of affairs in trauma studies and the relevance of trauma in Smith’s work as represented in White Teeth and NW. For the purpose of this paper, I will provide a close reading of “The Embassy of Cambodia” and I will rely on Michael Rothberg’s theory of multidirectional memory to illustrate how the history of genocide in Cambodia and the history of the protagonist of the story, which is effectively one of slavery, conflate in Smith’s text to bring to the fore silenced histories in a more ethical manner that seeks to put an end to competition and hierarchies within traumatic histories and trauma theory. This paper will explore the different juxtapositions that the story offers between individual and collective experiences of trauma and, in its explorations of multidirectional memory, the juxtaposition of collective histories of suffering
In situ conservation of crop wild relatives
Poster presented at 13. Meeting of the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA) held in FAO, Rome (Italy), 18-22 Feb 200
The Economic Value of Basin Protection to Improve the Quality and Reliability of Potable Water Supply: Some Evidence from Ecuador
This study estimates the willingness to pay (WTP) of Loja’s households to protect two micro-basins that supply over 40 percent of potable water to the city. Results indicate that households have an average WTP of $5.80 per month, which corresponds to a 25 percent increase in the self-reported monthly water bill, to preserve the basins.Basin protection, contingent valuation, Loja, Ecuador, Environmental Economics and Policy, Land Economics/Use,
A crop wild relative global portal. Meeting the information challenge for CWR in situ conservation
Lepton masses and mixing without Yukawa hierarchies
We investigate the neutrino masses and mixing patten in a version of the
model with one extra exotic charged
lepton per family as introduced by Ozer. It is shown that an extended scalar
sector, together with a discrete symmetry, is able to reproduce a
consistent lepton mass spectrum without a hierarchy in the Yukawa coupling
constants, the former as a carefull balance between one universal see-saw and
two radiative mechanisms.Comment: 7 pages, 2 figures, accepted for publication in Phys. Rev. D
Pre- and Post-burst Radio Observations of the Class 0 Protostar HOPS 383 in Orion
There is increasing evidence that episodic accretion is a common phenomenon
in Young Stellar Objects (YSOs). Recently, the source HOPS 383 in Orion was
reported to have a mid-infrared -- and bolometric -- luminosity
increase between 2004 and 2008, constituting the first clear example of a class
0 YSO (a protostar) with a large accretion burst. The usual assumption that in
YSOs accretion and ejection follow each other in time needs to be tested. Radio
jets at centimeter wavelengths are often the only way of tracing the jets from
embedded protostars. We searched the Very Large Array archive for the available
observations of the radio counterpart of HOPS 383. The data show that the radio
flux of HOPS 383 varies only mildly from January 1998 to December 2014, staying
at the level of to 300 Jy in the X band ( GHz), with a
typical uncertainty of 10 to 20 Jy in each measurement. We interpret the
absence of a radio burst as suggesting that accretion and ejection enhancements
do not follow each other in time, at least not within timescales shorter than a
few years. Time monitoring of more objects and specific predictions from
simulations are needed to clarify the details of the connection betwen
accretion and jets/winds in YSOs.Comment: ApJ Letters, in pres
Oscillatory decay of a two-component Bose-Einstein condensate
We study the decay of a two-component Bose-Einstein condensate with negative
effective interaction energy. With a decreasing atom number due to losses, the
atom-atom interaction becomes less important and the system undergoes a
transition from a bistable Josephson regime to the monostable Rabi regime,
displaying oscillations in phase and number. We study the equations of motion
and derive an analytical expression for the oscillation amplitude. A quantum
trajectory simulation reveals that the classical description fails for low
emission rates, as expected from analytical considerations. Observation of the
proposed effect will provide evidence for negative effective interaction.Comment: 4 pages, 3 figue
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