289 research outputs found
Hamilton-Jacobi approach to Berezinian singular systems
In this work we present a formal generalization of the Hamilton-Jacobi
formalism, recently developed for singular systems, to include the case of
Lagrangians containing variables which are elements of Berezin algebra. We
derive the Hamilton-Jacobi equation for such systems, analizing the singular
case in order to obtain the equations of motion as total differential equations
and study the integrability conditions for such equations. An example is solved
using both Hamilton-Jacobi and Dirac's Hamiltonian formalisms and the results
are compared.Comment: LaTex, 30 pages, no figure
Fermionic Linear Optics Revisited
We provide an alternative view of the efficient classical simulatibility of
fermionic linear optics in terms of Slater determinants. We investigate the
generic effects of two-mode measurements on the Slater number of fermionic
states. We argue that most such measurements are not capable (in conjunction
with fermion linear optics) of an efficient exact implementation of universal
quantum computation. Our arguments do not apply to the two-mode parity
measurement, for which exact quantum computation becomes possible, see
quant-ph/0401066.Comment: 16 pages, submitted to the special issue of Foundation of Physics in
honor of Asher Peres' 70th birthda
The State in Retreat? Why has India Experienced Such Half?hearted ‘Liberalisation’ in the 1980s?
Summary Summary The promise of economic liberalisation in the 1985 Budget and the rapid retreat from it that ensued, are described and then explained in relation to long?term trends of India's political economy. The very half?hearted liberalisation that took place can be understood as the outcome of fiscal problems of long?standing; and these in turn are the result of the compromise of power between propertied classes (Bardhan's model) and the weakness of the state as an organisation. The Rajiv regime did attempt to reassert the autonomy of high politics, but the attempt was short?lived because of the lack of political capacity to confront propertied groups — amongst which there are strong interests in the maintenance of regulation. Resumen Resumen ¿El estado en retirada? ¿Por qué India experimentó una ‘liberalización’ tan tenue en la décade de 1980? Se describe la liberalización económica anunciada en el presupuesto de 1985 de la India y su rápido abandono, explicándose ésto por las tendencias de largo plazo de su economía política. La liberalización extremadamente suave que tuvo lugar, puede entenderse como resultado de problemas fiscales de larga data. Esto a su vez, es consecuencia del compromiso de poder entre las clases propietarias (mode 10 Bardhan) y la debilidad de la organización estatal. El régimen Rajiv intentó reasegurar la autonomía de la alta política, pero el intento fue de corta duración por la insuficiente capacidad para enfrentar a los grupos proprietarios, entre los cuales hay fuertes intereses para mantener la regulación
Geometrodynamical Formulation of Two-Dimensional Dilaton Gravity
Two-dimensional matterless dilaton gravity with arbitrary dilatonic potential
can be discussed in a unitary way, both in the Lagrangian and canonical
frameworks, by introducing suitable field redefinitions. The new fields are
directly related to the original spacetime geometry and in the canonical
picture they generalize the well-known geometrodynamical variables used in the
discussion of the Schwarzschild black hole. So the model can be quantized using
the techniques developed for the latter case. The resulting quantum theory
exhibits the Birkhoff theorem at the quantum level.Comment: 15 pages, LATE
Characterising the impact of heatwaves on work-related injuries and illnesses in three Australian cities using a standard heatwave definition- Excess Heat Factor (EHF)
BACKGROUND AND AIMS:Heatwaves have potential health and safety implications for many workers, and heatwaves are predicted to increase in frequency and intensity with climate change. There is currently a lack of comparative evidence for the effects of heatwaves on workers' health and safety in different climates (sub-tropical and temperate). This study examined the relationship between heatwave severity (as defined by the Excess Heat Factor) and workers' compensation claims, to define impacts and identify workers at higher risk. METHODS:Workers' compensation claims data from Australian cities with temperate (Melbourne and Perth) and subtropical (Brisbane) climates for the years 2006-2016 were analysed in relation to heatwave severity categories (low and moderate/high severity) using time-stratified case-crossover models. RESULTS:Consistent impacts of heatwaves were observed in each city with either a protective or null effect during heatwaves of low-intensity while claims increased during moderate/high-severity heatwaves compared with non-heatwave days. The highest effect during moderate/high-severity heatwaves was in Brisbane (RR 1.45, 95% CI: 1.42-1.48). Vulnerable worker subgroups identified across the three cities included: males, workers aged under 34 years, apprentice/trainee workers, labour hire workers, those employed in medium and heavy strength occupations, and workers from outdoor and indoor industrial sectors. CONCLUSION:These findings show that work-related injuries and illnesses increase during moderate/high-severity heatwaves in both sub-tropical and temperate climates. Heatwave forecasts should signal the need for heightened heat awareness and preventive measures to minimise the risks to workers.Blesson M. Varghese, Adrian G. Barnett, Alana L. Hansen, Peng Bi, John Nairn, Shelley Rowett, Monika Nitschke, Scott Hanson-Easey, Jane S. Heyworth, Malcolm R. Sim, Dino L. Pisaniell
Measurement of inclusive charged current interactions on carbon in a few-GeV neutrino beam
We report a measurement of inclusive charged current interactions of muon neutrinos on carbon with an average energy of 0.8 GeV using the Fermilab Booster Neutrino Beam. We compare our measurement with two neutrino interaction simulations: NEUT and NUANCE. The charged current interaction rates (product of flux and cross section) are extracted by fitting the muon kinematics, with a precision of 6%-15% for the energy dependent and 3% for the energy integrated analyses. We also extract charged current inclusive interaction cross sections from the observed rates, with a precision of 10%-30% for the energy dependent and 8% for the energy integrated analyses. This is the first measurement of the charged current inclusive cross section on carbon around 1 GeV. These results can be used to convert previous SciBooNE cross-section ratio measurements to absolute cross-section values. © 2011 American Physical Society
Improved measurement of neutral current coherent π0 production on carbon in a few-GeV neutrino beam
The SciBooNE Collaboration reports a measurement of neutral current coherent π0 production on carbon by a muon neutrino beam with average energy 0.8 GeV. The separation of coherent from inclusive π0 production has been improved by detecting recoil protons from resonant π0 production. We measure the ratio of the neutral current coherent π0 production to total charged current cross sections to be (1.16±0.24)×10-2. The ratio of charged current coherent π+ to neutral current coherent π0 production is calculated to be 0.14-0.28+0.30, using our published charged current coherent pion measurement. © 2010 The American Physical Society
Search for charged current coherent pion production on carbon in a few-GeV neutrino beam
The SciBooNE Collaboration has performed a search for charged current coherent pion production from muon neutrinos scattering on carbon, νμC12→μ-C12π+, with two distinct data samples. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio of charged current coherent pion production to the total charged current cross section at 0.67×10-2 at mean neutrino energy 1.1 GeV and 1.36×10-2 at mean neutrino energy 2.2 GeV. © 2008 The American Physical Society
Measurement of inclusive neutral current π0 production on carbon in a few-GeV neutrino beam
The SciBooNE Collaboration reports inclusive neutral current neutral pion production by a muon neutrino beam on a polystyrene target (C8H8). We obtain (7.7±0.5(stat)±0.5(sys))×10-2 as the ratio of the neutral current neutral pion production to total charged current cross section; the mean energy of neutrinos producing detected neutral pions is 1.11/2 GeV. The result agrees with the Rein-Sehgal model implemented in our neutrino interaction simulation program with nuclear effects. The spectrum shape of the π0 momentum and angle agree with the model. We also measure the ratio of the neutral current coherent pion production to total charged current cross section to be (0.7±0.4)×10-2. © 2010 The American Physical Society
Measurement of K\u3csup\u3e+\u3c/sup\u3e production cross section by 8 GeV protons using high-energy neutrino interactions in the SciBooNE detector
The SciBooNE Collaboration reports K+ production cross section and rate measurements using high-energy daughter muon neutrino scattering data off the SciBar polystyrene (C8H8) target in the SciBooNE detector. The K+ mesons are produced by 8 GeV protons striking a beryllium target in Fermilab Booster Neutrino Beam line (BNB). Using observed neutrino and antineutrino events in SciBooNE, we measure d2σdpdΩ=(5. 34±0.76)mb/(GeV/c×sr) for p+Be→K++X at mean K + energy of 3.9 GeV and angle (with respect to the proton beam direction) of 3.7 degrees, corresponding to the selected K+ sample. Compared to Monte Carlo predictions using previous higher energy K+ production measurements, this measurement, which uses the NUANCE neutrino interaction generator, is consistent with a normalization factor of 0.85±0.12. This agreement is evidence that the extrapolation of the higher energy K+ measurements to an 8 GeV beam energy using Feynman scaling is valid. This measurement reduces the error on the K+ production cross section from 40% to 14%. © 2011 American Physical Society
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