Search results for " Limits"
showing 10 items of 134 documents
Towards extracting the timelike pion form factor on CLS 2-flavour ensembles
2016
Results are presented from an ongoing study of the $\rho$ resonance. We use the distillation approach in order to create correlator matrices involving $\rho$ and $\pi\pi$ interpolators. The study is done in a centre-of-mass frame and several moving frames. We are able to extract energy levels by solving the GEVP of those correlator matrices. The initial exploratory study is being done on a CLS 2-flavour lattice with a pion mass of $451$ $\mathrm{MeV}$ using $\mathcal{O}(a)$ improved Wilson fermions. One aim of this work is to extract the timelike pion form factor after applying the L\"uscher formalism. We also plan to integrate this study with the existing Mainz programme for the calculatio…
The leading hadronic contribution to (g-2) of the muon: The chiral behavior using the mixed representation method
2015
We extend our analysis of the leading hadronic contribution to the anomalous magnetic moment of the muon using the mixed representation method to study its chiral behavior. We present results derived from local-conserved two-point lattice vector correlation functions, computed on a subset of light two-flavor ensembles made available to us through the CLS effort with pion masses as low as 190 MeV. The data is analyzed also using the more standard four-momentum method. Both methods are systematically compared as the calculations approach the physical point.
Excited state systematics in extracting nucleon electromagnetic form factors
2012
We present updated preliminary results for the nucleon electromagnetic form factors for non-perturbatively $\mathcal{O}(a)$ improved Wilson fermions in $N_f=2$ QCD measured on the CLS ensembles. The use of the summed operator insertion method allows us to suppress the influence of excited states in our measurements. A study of the effect that excited state contaminations have on the $Q^2$ dependence of the extracted nucleon form factors may then be made through comparisons of the summation method to standard plateau fits, as well as to excited state fits.
Durée et catastrophe. Régimes temporels et conflits écologiques à l’heure de la globalisation de l’environnement
2020
Elaborating from anthropology of nature and semiotic of culture, the work aims to illustrate that every ecological crisis is, also, a temporality crisis. In order to do so, it compares different visions of future – and, therefore, of the present of the enunciator – that shape international environmental crisis between ’60 and ’70. The first, insisting on risks, comes from Massachusetts Institute of Technology, advising about the Limits to Growth; the second, insisting on risk normalization, comes from UN first Earth Summit; both discourses are registered in reports published in 1972 and read worldwide. The analysis shows that while the MIT report successfully points the temporality crisis r…
Improving the prediction of air pollution peak episodes generated by urban transport networks
2016
Abstract This paper illustrates the early results of ongoing research developing novel methods to analyse and simulate the relationship between trasport-related air pollutant concentrations and easily accessible explanatory variables. The final scope is to integrate the new models in traditional traffic management support systems for a sustainable mobility of road vehicles in urban areas. This first stage concerns the relationship between the hourly mean concentration of nitrogen dioxide (NO2) and explanatory factors reflecting the NO2 mean level one hour back, along with traffic and weather conditions. Particular attention is given to the prediction of pollution peaks, defined as exceedanc…
The use of a European coinage alloy to compare the detection limits of mobile XRF systems. A feasibility study
2007
The investigation of archaeological and historical materials makes use of techniques that, though borrowed from other fields of research and industrial production, frequently have to be 're-invented' because of peculiar characteristics of the analysed objects. Artistic relevance, limited movability, compositional and structural heterogeneity radically change the experimental approach and often require ad hoc designed equipment. These considerations also apply to x-ray fluorescence, especially regarding mobile systems. The extensive development and use of mobile spectrometers has produced an extremely diversified context and created the need for common criteria to evaluate their performances…
Weighted limits in simplicial homotopy theory
2010
Abstract By combining ideas of homotopical algebra and of enriched category theory, we explain how two classical formulas for homotopy colimits, one arising from the work of Quillen and one arising from the work of Bousfield and Kan, are instances of general formulas for the derived functor of the weighted colimit functor.
Rigged Hilbert spaces and contractive families of Hilbert spaces
2013
The existence of a rigged Hilbert space whose extreme spaces are, respectively, the projective and the inductive limit of a directed contractive family of Hilbert spaces is investigated. It is proved that, when it exists, this rigged Hilbert space is the same as the canonical rigged Hilbert space associated to a family of closable operators in the central Hilbert space.
Jacobian of weak limits of Sobolev homeomorphisms
2016
Abstract Let Ω be a domain in ℝ n {\mathbb{R}^{n}} , where n = 2 , 3 {n=2,3} . Suppose that a sequence of Sobolev homeomorphisms f k : Ω → ℝ n {f_{k}\colon\Omega\to\mathbb{R}^{n}} with positive Jacobian determinants, J ( x , f k ) > 0 {J(x,f_{k})>0} , converges weakly in W 1 , p ( Ω , ℝ n ) {W^{1,p}(\Omega,\mathbb{R}^{n})} , for some p ⩾ 1 {p\geqslant 1} , to a mapping f. We show that J ( x , f ) ⩾ 0 {J(x,f)\geqslant 0} a.e. in Ω. Generalizations to higher dimensions are also given.
Low-Noise Amplification and Frequency Conversion with a Multiport Microwave Optomechanical Device
2016
High-gain amplifiers of electromagnetic signals operating near the quantum limit are crucial for quantum information systems and ultrasensitive quantum measurements. However, the existing techniques have a limited gain-bandwidth product and only operate with weak input signals. Here we demonstrate a two-port optomechanical scheme for amplification and routing of microwave signals, a system that simultaneously performs high-gain amplification and frequency conversion in the quantum regime. Our amplifier, implemented in a two-cavity microwave optomechanical device, shows 41 dB of gain and has a high dynamic range, handling input signals up to $10^{13}$ photons per second, three orders of magn…