Non-disturbing quantum measurements

We consider pairs of quantum observables (POVMs) and analyze the relation between the notions of non-disturbance, joint measurability and commutativity. We specify conditions under which these properties coincide or differ---depending for instance on the interplay between the number of outcomes and the Hilbert space dimension or on algebraic properties of the effect operators. We also show that (non-)disturbance is in general not a symmetric relation and that it can be decided and quantified by means of a semidefinite program.Comment: Minor corrections in v

Sensory acceptance of organic and conventional food by children in the age of 2 to 7 years

This study is initialized to find out which sensory factors might influence the acceptance of organic food by young children. 138 children aged from 2 to 7 years were recruited at the German Research Institute of Child Nutrition in Dortmund. All these children are participating in the DONALD-Study. Detailed nutrition records are available about breastfeeding and feeding of these children from birth to the age of one and further on. In a 2-year testing-period children tasted organic and conventional food in two-sided Paired Comparison Tests. In both years parents were asked a number of questions, mainly about the nutrition behaviour of their children. Sensory tests were analyzed and connected in different ways: with data of sensory profiles, nutrition records and different questionnaires

Non-Markovianity in atom-surface dispersion forces

We discuss the failure of the Markov approximation in the description of atom-surface fluctuation-induced interactions, both at equilibrium (Casimir-Polder forces) and out-of-equilibrium (quantum friction). Using general theoretical arguments, we show that the Markov approximation can lead to erroneous predictions of such phenomena with regard to both strength and functional dependencies on system parameters. Our findings highlight the importance of non-Markovian effects in dispersion interactions. In particular, we show that the long-time power-law tails of temporal correlations, and the corresponding low-frequency behavior, of two-time dipole correlations, neglected in the Markovian limit, dramatically affect the prediction of the force.Comment: 17 pages, 6 figure

Fitting in a complex chi^2 landscape using an optimized hypersurface sampling

Fitting a data set with a parametrized model can be seen geometrically as finding the global minimum of the chi^2 hypersurface, depending on a set of parameters {P_i}. This is usually done using the Levenberg-Marquardt algorithm. The main drawback of this algorithm is that despite of its fast convergence, it can get stuck if the parameters are not initialized close to the final solution. We propose a modification of the Metropolis algorithm introducing a parameter step tuning that optimizes the sampling of parameter space. The ability of the parameter tuning algorithm together with simulated annealing to find the global chi^2 hypersurface minimum, jumping across chi^2{P_i} barriers when necessary, is demonstrated with synthetic functions and with real data

Position Reconstruction in Drift Chambers operated with Xe, CO2 (15%)

We present measurements of position and angular resolution of drift chambers operated with a Xe,CO$_2$(15%) mixture. The results are compared to Monte Carlo simulations and important systematic effects, in particular the dispersive nature of the absorption of transition radiation and non-linearities, are discussed. The measurements were carried out with prototype drift chambers of the ALICE Transition Radiation Detector, but our findings can be generalized to other drift chambers with similar geometry, where the electron drift is perpendicular to the wire planes.Comment: 30 pages, 18 figure

Pseudorapidity dependence of the anisotropic flow of charged particles in Pb?Pb collisions at View the MathML source

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Measuring K 0 S K ± interactions using Pb–Pb collisions at √sNN = 2 . 76 TeV

We present the first ever measurements of femtoscopic correlations between the Kos and K± particles. The analysis was performed on the data from Pb–Pb collisions at √sNN=2.76 TeV measured by the ALICE experiment. The observed femtoscopic correlations are consistent with final-state interactions proceeding via the a0(980) resonance. The extracted kaon source radius and correlation strength parameters for K os K- are found to be equal within the experimental uncertainties to those for K os K+ . Comparing the results of the present study with those from published identical-kaon femtoscopic studies by ALICE, mass and coupling parameters for the ao resonance are tested. Our results are also compatible with the interpretation of the ao having a tetraquark structure instead of that of a diquark

W and Z boson production in p-Pb collisions at √sNN=5.02 TeV

The W and Z boson production was measured via the muonic decay channel in proton-lead collisions at sNN−−−√=5.02 TeV at the Large Hadron Collider with the ALICE detector. The measurement covers backward (−4.46 10 GeV/c are determined. The results are compared to theoretical calculations both with and without including the nuclear modification of the parton distribution functions. The W-boson production is also studied as a function of the collision centrality: the cross section of muons from W-boson decays is found to scale with the average number of binary nucleon-nucleon collisions within uncertainties