1,026 research outputs found
Mars Spacecraft Power System Development Final Report
Development of optimum Mariner spacecraft power system for application to future flyby and orbiter mission
A tight Tsirelson inequality for infinitely many outcomes
We present a novel tight bound on the quantum violations of the CGLMP
inequality in the case of infinitely many outcomes. Like in the case of
Tsirelson's inequality the proof of our new inequality does not require any
assumptions on the dimension of the Hilbert space or kinds of operators
involved. However, it is seen that the maximal violation is obtained by the
conjectured best measurements and a pure, but not maximally entangled, state.
We give an approximate state which, in the limit where the number of outcomes
tends to infinity, goes to the optimal state for this setting. This state might
be potentially relevant for experimental verifications of Bell inequalities
through multi-dimenisonal entangled photon pairs.Comment: 5 pages, 2 figures; improved presentation, change in title, as
published
DebtRank: Too central to fail? Financial networks, the FED and systemic risk
Systemic risk, here meant as the risk of default of a large portion of the financial system, depends on the network of financial exposures among institutions. However, there is no widely accepted methodology to determine the systemically important nodes in a network. To fill this gap, we introduce, DebtRank, a novel measure of systemic impact inspired by feedback-centrality. As an application, we analyse a new and unique dataset on the USD 1.2 trillion FED emergency loans program to global financial institutions during 2008g-2010. We find that a group of 22 institutions, which received most of the funds, form a strongly connected graph where each of the nodes becomes systemically important at the peak of the crisis. Moreover, a systemic default could have been triggered even by small dispersed shocks. The results suggest that the debate on too-big-to-fail institutions should include the even more serious issue of too-central-to-fail
Optical computing of quantum revivals
Interference is the mechanism through which waves can be structured into the
most fascinating patterns. While for sensing, imaging, trapping, or in
fundamental investigations, structured waves play nowadays an important role
and are becoming subject of many interesting studies. Using a coherent optical
field as a probe, we show how to structure light into distributions presenting
collapse and revival structures in its wavefront. These distributions are
obtained from the Fourier spectrum of an arrangement of aperiodic diffracting
structures. Interestingly, the resulting interference may present quasiperiodic
structures of diffraction peaks on a number of distance scales, even though the
diffracting structure is not periodic. We establish an analogy with revival
phenomena in the evolution of quantum mechanical systems and illustrate this
computation numerically and experimentally, obtaining excellent agreement with
the proposed theory.Comment: 10 pages, 4 figure
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