15,921 research outputs found
Impact of the Delta (1232) resonance on neutral pion photoproduction in chiral perturbation theory
We present an ongoing project to assess the importance of D-waves and the
resonance for descriptions of neutral pion photoproduction in
Heavy Baryon Chiral Perturbation Theory. This research has been motivated by
data published by the A2 and CB-TAPS collaborations at MAMI [1]. This data has
reached unprecedented levels of accuracy from threshold through to the
resonance. Accompanying the experimental work, there has also been a series of
publications studying the theory that show that, to go beyond an energy of
MeV, it is necessary to include other aspects, in particular the
as a degree of freedom [2] and possibly higher partial waves
[3].Comment: Proceedings to the 8th International Workshop on Chiral Dynamics 201
Extension Ideal Development Address
Development of the Extension Ideal in the Association of Land-Grant Colleges and Universities, an address prepared for delivery May 8, 1944, before the Mu Chapter, Epsilon Sigma Phi, Washington, D.C., by W. A. Lloyd.https://scholarsjunction.msstate.edu/ua-vertical-file/1065/thumbnail.jp
Buyer power in U.K. food retailing: a 'first-pass' test
Habtu Weldegebriel, University of Warwick
Abstract
The potential existence of buyer power in U.K. food retailing has attracted the scrutiny of the U.K.'s anti-trust authorities, culminating in the second of two comprehensive regulatory inquiries in recent years. Such inquiries are authoritative but correspondingly time-consuming and costly. Moreover, detection of buyer power has been dogged by the paucity of reliable evidence of its existence. In this paper, we present a simple theoretical model of oligopsony which delivers quasi-reduced form retailer-producer pricing equations with which the null of perfect competition can be tested using readily available market data. Using a cointegrated vector autoregression, we find empirical results that show the null of perfect competition can be rejected in seven of the nine food products investigated. Though not conclusive on the existence of buyer power, the proposed test offers a means via which the behaviour of the retail-producer price spread is consistent with it. At the very least, it can corroborate the concerns of the anti-trust authorities as to whether buyer power is potentially one source of concern
Exponential complexity of an adiabatic algorithm for an NP-complete problem
We prove an analytical expression for the size of the gap between the ground
and the first excited state of quantum adiabatic algorithm for the
3-satisfiability, where the initial Hamiltonian is a projector on the subspace
complementary to the ground state. For large problem sizes the gap decreases
exponentially and as a consequence the required running time is also
exponential.Comment: 5 pages, 2 figures; v3. published versio
Probing spacetime foam with extragalactic sources
Due to quantum fluctuations, spacetime is probably ``foamy'' on very small
scales. We propose to detect this texture of spacetime foam by looking for
core-halo structures in the images of distant quasars. We find that the Very
Large Telescope interferometer will be on the verge of being able to probe the
fabric of spacetime when it reaches its design performance. Our method also
allows us to use spacetime foam physics and physics of computation to infer the
existence of dark energy/matter, independent of the evidence from recent
cosmological observations.Comment: LaTeX, 11 pages, 1 figure; version submitted to PRL; several
references added; very useful comments and suggestions by Eric Perlman
incorporate
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