190 research outputs found
Relational Quantum Mechanics and Probability
We present a derivation of the third postulate of Relational Quantum
Mechanics (RQM) from the properties of conditional probabilities.The first two
RQM postulates are based on the information that can be extracted from
interaction of different systems, and the third postulate defines the
properties of the probability function. Here we demonstrate that from a
rigorous definition of the conditional probability for the possible outcomes of
different measurements, the third postulate is unnecessary and the Born's rule
naturally emerges from the first two postulates by applying the Gleason's
theorem. We demonstrate in addition that the probability function is uniquely
defined for classical and quantum phenomena. The presence or not of
interference terms is demonstrated to be related to the precise formulation of
the conditional probability where distributive property on its arguments cannot
be taken for granted. In the particular case of Young's slits experiment, the
two possible argument formulations correspond to the possibility or not to
determine the particle passage through a particular path.Comment: Foundations of Physics, Springer Verlag, 201
Doppler-tuned Bragg Spectroscopy of Excited Levels in He-Like Uranium: a discussion of the uncertainty contributions
We present the uncertainty discussion of a recent experiment performed at the
GSI storage ring ESR for the accurate energy measurement of the He-like uranium
1s2p3P2- 1s2s3S1 intra-shell transition. For this propose we used a Johann-type
Bragg spectrometer that enables to obtain a relative energy measurement between
the He-like uranium transition, about 4.51 keV, and a calibration x-ray source.
As reference, we used the Ka fluorescence lines of zinc and the Li-like uranium
1s22p2P3/2 - 1 s22s 2S1/2 intra-shell transition from fast ions stored in the
ESR. A comparison of the two different references, i.e., stationary and moving
x-ray source, and a discussion of the experimental uncertainties is presented
Doppler-tuned Bragg Spectroscopy of Excited Levels in He-Like Uranium: a discussion of the uncertainty contributions
We present the uncertainty discussion of a recent experiment performed at the
GSI storage ring ESR for the accurate energy measurement of the He-like uranium
1s2p3P2- 1s2s3S1 intra-shell transition. For this propose we used a Johann-type
Bragg spectrometer that enables to obtain a relative energy measurement between
the He-like uranium transition, about 4.51 keV, and a calibration x-ray source.
As reference, we used the Ka fluorescence lines of zinc and the Li-like uranium
1s22p2P3/2 - 1 s22s 2S1/2 intra-shell transition from fast ions stored in the
ESR. A comparison of the two different references, i.e., stationary and moving
x-ray source, and a discussion of the experimental uncertainties is presented
Doppler-tuned Bragg Spectroscopy of Excited Levels in He-Like Uranium: a discussion of the uncertainty contributions
We present the uncertainty discussion of a recent experiment performed at the
GSI storage ring ESR for the accurate energy measurement of the He-like uranium
1s2p3P2- 1s2s3S1 intra-shell transition. For this propose we used a Johann-type
Bragg spectrometer that enables to obtain a relative energy measurement between
the He-like uranium transition, about 4.51 keV, and a calibration x-ray source.
As reference, we used the Ka fluorescence lines of zinc and the Li-like uranium
1s22p2P3/2 - 1 s22s 2S1/2 intra-shell transition from fast ions stored in the
ESR. A comparison of the two different references, i.e., stationary and moving
x-ray source, and a discussion of the experimental uncertainties is presented
Mean shift cluster recognition method implementation in the nested sampling algorithm
Nested sampling is an efficient algorithm for the calculation of the Bayesian evidence and posterior parameter probability distributions. It is based on the step-by-step exploration of the parameter space by Monte Carlo sampling with a series of values sets called live points that evolve towards the region of interest, i.e. where the likelihood function is maximal. In presence of several local likelihood maxima, the algorithm converges with difficulty. Some systematic errors can also be introduced by unexplored parameter volume regions. In order to avoid this, different methods are proposed in the literature for an efficient search of new live points, even in presence of local maxima. Here we present a new solution based on the mean shift cluster recognition method implemented in a random walk search algorithm. The clustering recognition is integrated within the Bayesian analysis program NestedFit. It is tested with the analysis of some difficult cases. Compared to the analysis results without cluster recognition, the computation time is considerably reduced. At the same time, the entire parameter space is efficiently explored, which translates into a smaller uncertainty of the extracted value of the Bayesian evidence
Extension of charge-state-distribution calculations for ion-solid collisions towards low velocities and many-electron ions
Knowledge of the detailed evolution of the whole charge-state distribution of projectile ions colliding with targets is required in several fields of research such as material science and atomic and nuclear physics but also in accelerator physics, and in particular in regard to the several foreseen large-scale facilities. However, there is a lack of data for collisions in the nonperturbative energy domain and that involve many-electron projectiles. Starting from the etacha model we developed [Rozet, Nucl. Instrum. Methods Phys. Res., Sect. B 107, 67 (1996)10.1016/0168-583X(95)00800-4], we present an extension of its validity domain towards lower velocities and larger distortions. Moreover, the system of rate equations is able to take into account ions with up to 60 orbital states of electrons. The computed data from the different new versions of the etacha code are compared to some test collision systems. The improvements made are clearly illustrated by 28.9MeVu-1Pb56+ ions, and laser-generated carbon ion beams of 0.045 to 0.5MeVu-1, passing through carbon or aluminum targets, respectively. Hence, those new developments can efficiently sustain the experimental programs that are currently in progress on the "next-generation" accelerators or laser facilities.Fil: Lamour, E.. Centre National de la Recherche Scientifique; Francia. Universite de Paris; FranciaFil: Fainstein, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Galassi, Mariel Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Prigent, C.. Centre National de la Recherche Scientifique; Francia. Universite de Paris; FranciaFil: Ramirez, C. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Rivarola, Roberto Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Rozet, J. P.. Centre National de la Recherche Scientifique; Francia. Universite de Paris; FranciaFil: Trassinelli, M.. Centre National de la Recherche Scientifique; Francia. Universite de Paris; FranciaFil: Vernhet, D.. Centre National de la Recherche Scientifique; Francia. Universite de Paris; Franci
Characterization of a CCD array for Bragg spectroscopy
The average pixel distance as well as the relative orientation of an array of
6 CCD detectors have been measured with accuracies of about 0.5 nm and 50
rad, respectively. Such a precision satisfies the needs of modern crystal
spectroscopy experiments in the field of exotic atoms and highly charged ions.
Two different measurements have been performed by illuminating masks in front
of the detector array by remote sources of radiation. In one case, an aluminum
mask was irradiated with X-rays and in a second attempt, a nanometric quartz
wafer was illuminated by a light bulb. Both methods gave consistent results
with a smaller error for the optical method. In addition, the thermal expansion
of the CCD detectors was characterized between -105 C and -40 C.Comment: Submitted to Review of Scientific Instrument
Measurement of the charged pion mass using X-ray spectroscopy of exotic atoms
The transitions in pionic nitrogen and muonic oxygen were measured
simultaneously by using a gaseous nitrogen-oxygen mixture at 1.4\,bar. Due to
the precise knowledge of the muon mass the muonic line provides the energy
calibration for the pionic transition. A value of
(139.57077\,\,0.00018)\,MeV/c (\,1.3ppm) is derived for the
mass of the negatively charged pion, which is 4.2ppm larger than the present
world average
Modulating the phase transition temperature of giant magnetocaloric thin films by ion irradiation
Magnetic refrigeration based on the magnetocaloric effect at room temperature
is one of the most attractive alternative to the current gas
compression/expansion method routinely employed. Nevertheless, in giant
magnetocaloric materials, optimal refrigeration is restricted to the narrow
temperature window of the phase transition (Tc). In this work, we present the
possibility of varying this transition temperature into a same giant
magnetocaloric material by ion irradiation. We demonstrate that the transition
temperature of iron rhodium thin films can be tuned by the bombardment of ions
of Ne 5+ with varying fluences up to 10 14 ions cm --2 , leading to optimal
refrigeration over a large 270--380 K temperature window. The Tc modification
is found to be due to the ion-induced disorder and to the density of new
point-like defects. The variation of the phase transition temperature with the
number of incident ions opens new perspectives in the conception of devices
using giant magnetocaloric materials
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