3,023 research outputs found
Present and Future Prospects for GRB Standard Candles
Following our previous work, we conclude that a GRB standard candle
constructed from the Ghirlanda et al. power-law relation between the
geometry-corrected energy (E_gamma) and the peak of the rest-frame prompt burst
spectrum (E_p) is not yet cosmographically useful, despite holding some
potential advantages over SNe Ia. This is due largely to the small sample of
\~20 GRBs with the required measured redshifts, jet-breaks, and peak energies,
and to the strong sensitivity of the goodness-of-fit of the power-law to input
assumptions. The most important such finding concerns the sensitivity to the
generally unknown density (and density profile), of the circumburst medium.
Although the E_p-E_gamma relation is a highly significant correlation over many
cosmologies, until the sample expands to include many low-z events, it will be
most sensitive to Omega_M but essentially insensitive to Omega_Lambda and w,
with some hope of constraining dw/dt with high-z GRB data alone. The relation
clearly represents a significant improvement in the search for an empirical GRB
standard candle, but is further hindered by an unknown physical basis for the
relation, the lack of a low-z training set to calibrate the relation in a
cosmology-independent way, and several major potential systematic uncertainties
and selection effects. Until these concerns are addressed, a larger sample is
acquired, and attempts are made to marginalize or perform Monte Carlo
simulations over the unknown density distribution, we urge caution concerning
claims of the utility of GRBs for cosmography and especially the attempts to
combine GRBs with SNe Ia.Comment: 5 pages, 2 figures, "Proceedings, Gamma-Ray Bursts in the Afterglow
Era: 4th Workshop, Rome, Italy, Oct 18-22, 2004". Accepted to Il Nuovo
Cimento. For more details, see astro-ph/0408413 (ApJ accepted), and other
work from the cosmicbooms.net Team at http://www.cosmicbooms.net
Subcompact cardinals, squares, and stationary reflection
We generalise Jensen's result on the incompatibility of subcompactness with
square. We show that alpha^+-subcompactness of some cardinal less than or equal
to alpha precludes square_alpha, but also that square may be forced to hold
everywhere where this obstruction is not present. The forcing also preserves
other strong large cardinals. Similar results are also given for stationary
reflection, with a corresponding strengthening of the large cardinal assumption
involved. Finally, we refine the analysis by considering Schimmerling's
hierarchy of weak squares, showing which cases are precluded by
alpha^+-subcompactness, and again we demonstrate the optimality of our results
by forcing the strongest possible squares under these restrictions to hold.Comment: 18 pages. Corrections and improvements from referee's report mad
Financial Crises: Recent Experience in U.S. and International Markets
macroeconomics, financial crisis, crises, U.S. markets, international markets
Testing Bell's Inequality with Cosmic Photons: Closing the Setting-Independence Loophole
We propose a practical scheme to use photons from causally disconnected
cosmic sources to set the detectors in an experimental test of Bell's
inequality. In current experiments, with settings determined by quantum random
number generators, only a small amount of correlation between detector settings
and local hidden variables, established less than a millisecond before each
experiment, would suffice to mimic the predictions of quantum mechanics. By
setting the detectors using pairs of quasars or patches of the cosmic microwave
background, observed violations of Bell's inequality would require any such
coordination to have existed for billions of years --- an improvement of 20
orders of magnitude.Comment: 5 pages, 4 figures. Minor edits to closely match journal version to
be published in Physical Review Letter
Mr. President
This creative nonfiction essay describe the author\u27s memories of running for senior class president in high school
Theatres of Reality, Fiction, and Temporality: Vegard Vinge and Ida Müller’s \u3cem\u3eIbsen-Saga\u3c/em\u3e (2006 - 2015)
This dissertation examines the influence of modernist aesthetics and ideologies on contemporary, European and U.S. experimental theatre. I argue that modernist and contemporary experimental theatres offer competing notions of reality, fiction, and temporality, which I interrogate through Vegard Vinge and Ida Müller’s Ibsen-Saga. I illuminate this tension by reading current modes of performance against the Saga’s productions and work practices, as well as their aesthetic and ideological foundation in three modernist sources: the artificiality of Ibsen’s realism, the utopianism and totality of Richard Wagner’s Gesamtkunstwerk, and the temporal provocations of the historical avant-gardes. I contend that the Saga reanimates Ibsen, Wagner, and the avant-gardes’ modernist forms and ideas to reject the conventions of twenty-first century practice
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