3,499 research outputs found
The imprints of superstatistics in multiparticle production processes
We provide an update of the overview of imprints of Tsallis nonextensive
statistics seen in a multiparticle production processes. They reveal an
ubiquitous presence of power law distributions of different variables
characterized by the nonextensivity parameter q > 1. In nuclear collisions one
additionally observes a q-dependence of the multiplicity fluctuations
reflecting the finiteness of the hadronizing source. We present sum rules
connecting parameters q obtained from an analysis of different observables,
which allows us to combine different kinds of fluctuations seen in the data and
analyze an ensemble in which the energy (E), temperature (T) and multiplicity
(N) can all fluctuate. This results in a generalization of the so called
Lindhard's thermodynamic uncertainty relation. Finally, based on the example of
nucleus-nucleus collisions (treated as a quasi-superposition of nucleon-nucleon
collisions) we demonstrate that, for the standard Tsallis entropy with degree
of nonextensivity q < 1, the corresponding standard Tsallis distribution is
described by q' = 2 - q > 1.Comment: 12 pages, 3 figures. Based on invited talk given by Z.Wlodarczyk at
SigmaPhi2011 conference, Larnaka, Cyprus, 11-15 July 2011. To be published in
Cent. Eur. J. Phys. (2011
Estimating the inelasticity with the information theory approach
Using the information theory approach, in both its extensive and nonextensive
versions, we estimate the inelasticity parameter of hadronic reactions
together with its distribution and energy dependence from and
data. We find that the inelasticity remains essentially constant in energy
except for a variation around , as was originally expected.Comment: 14 pages, 8 figures. Misprints correcte
Consequences of temperature fluctuations in observables measured in high energy collisions
We review the consequences of intrinsic, nonstatistical temperature
fluctuations as seen in observables measured in high energy collisions. We do
this from the point of view of nonextensive statistics and Tsallis
distributions. Particular attention is paid to multiplicity fluctuations as a
first consequence of temperature fluctuations, to the equivalence of
temperature and volume fluctuations, to the generalized thermodynamic
fluctuations relations allowing us to compare fluctuations observed in
different parts of phase space, and to the problem of the relation between
Tsallis entropy and Tsallis distributions. We also discuss the possible
influence of conservation laws on these distributions and provide some examples
of how one can get them without considering temperature fluctuations.Comment: Revised version of the invited contribution to The European Physical
Journal A (Hadrons and Nuclei) topical issue about 'Relativistic Hydro- and
Thermodynamics in Nuclear Physics' guest eds. Tamas S. Biro, Gergely G.
Barnafoldi and Peter Va
RDF Querying
Reactive Web systems, Web services, and Web-based publish/
subscribe systems communicate events as XML messages, and in
many cases require composite event detection: it is not sufficient to react
to single event messages, but events have to be considered in relation to
other events that are received over time.
Emphasizing language design and formal semantics, we describe the
rule-based query language XChangeEQ for detecting composite events.
XChangeEQ is designed to completely cover and integrate the four complementary
querying dimensions: event data, event composition, temporal
relationships, and event accumulation. Semantics are provided as
model and fixpoint theories; while this is an established approach for rule
languages, it has not been applied for event queries before
Nonextensive thermal sources of cosmic rays?
The energy spectrum of cosmic rays (CR) exhibits power-like behavior with a
very characteristic "knee" structure. We consider a possibility that such a
spectrum could be generated by some specific nonstatistical temperature
fluctuations in the source of CR with the "knee" structure reflecting an abrupt
change of the pattern of such fluctuations. This would result in a generalized
nonextensive statistical model for the production of CR. The possible physical
mechanisms leading to these effects are discussed together with the resulting
chemical composition of the CR, which follows the experimentally observed
abundance of nuclei.Comment: 16 pages, 3 figures, rewritten and updated version, to be published
in Centr. Eur. J. Phy
Histiocytoid cardiomyopathy and microphthalmia with linear skin defects syndrome: phenotypes linked by truncating variants in NDUFB11
Variants in NDUFB11, which encodes a structural component of complex I of the mitochondrial respiratory chain (MRC), were recently independently reported to cause histiocytoid cardiomyopathy (histiocytoid CM) and microphthalmia with linear skin defects syndrome (MLS syndrome). Here we report an additional case of histiocytoid CM, which carries a de novo nonsense variant in NDUFB11 (ENST00000276062.8: c.262C > T; p.[Arg88*]) identified using whole-exome sequencing (WES) of a family trio. An identical variant has been previously reported in association with MLS syndrome. The case we describe here lacked the diagnostic features of MLS syndrome, but a detailed clinical comparison of the two cases revealed significant phenotypic overlap. Heterozygous variants in HCCS (which encodes an important mitochondrially targeted protein) and COX7B, which, like NDUFB11, encodes a protein of the MRC, have also previously been identified in MLS syndrome including a case with features of both MLS syndrome and histiocytoid CM. However, a systematic review of WES data from previously published histiocytoid CM cases, alongside four additional cases presented here for the first time, did not identify any variants in these genes. We conclude that NDUFB11 variants play a role in the pathogenesis of both histiocytoid CM and MLS and that these disorders are allelic (genetically related)
Heralded single photon absorption by a single atom
The emission and absorption of single photons by single atomic particles is a
fundamental limit of matter-light interaction, manifesting its quantum
mechanical nature. At the same time, as a controlled process it is a key
enabling tool for quantum technologies, such as quantum optical information
technology [1, 2] and quantum metrology [3, 4, 5, 6]. Controlling both emission
and absorption will allow implementing quantum networking scenarios [1, 7, 8,
9], where photonic communication of quantum information is interfaced with its
local processing in atoms. In studies of single-photon emission, recent
progress includes control of the shape, bandwidth, frequency, and polarization
of single-photon sources [10, 11, 12, 13, 14, 15, 16, 17], and the
demonstration of atom-photon entanglement [18, 19, 20]. Controlled absorption
of a single photon by a single atom is much less investigated; proposals exist
but only very preliminary steps have been taken experimentally such as
detecting the attenuation and phase shift of a weak laser beam by a single atom
[21, 22], and designing an optical system that covers a large fraction of the
full solid angle [23, 24, 25]. Here we report the interaction of single
heralded photons with a single trapped atom. We find strong correlations of the
detection of a heralding photon with a change in the quantum state of the atom
marking absorption of the quantum-correlated heralded photon. In coupling a
single absorber with a quantum light source, our experiment demonstrates
previously unexplored matter-light interaction, while opening up new avenues
towards photon-atom entanglement conversion in quantum technology.Comment: 10 pages, 4 figure
Equivalence of volume and temperature fluctuations in power-law ensembles
Relativistic particle production often requires the use of Tsallis statistics
to account for the apparently power-like behavior of transverse momenta
observed in the data even at a few GeV/c. In such an approach this behavior is
attributed to some specific intrinsic fluctuations of the temperature in
the hadronizing system and is fully accounted by the nonextensivity parameter
. On the other hand, it was recently shown that similar power-law spectra
can also be obtained by introducing some specific volume fluctuations,
apparently without invoking the introduction of Tsallis statistics. We
demonstrate that, in fact, when the total energy is kept constant, these volume
fluctuations are equivalent to temperature fluctuations and can be derived from
them. In addition, we show that fluctuations leading to multiparticle power-law
Tsallis distributions introduce specific correlations between the considered
particles. We then propose a possible way to distinguish the fluctuations in
each event from those occurring from event-to-event. This could have
applications in the analysis of high density events at LHC (and especially in
ALICE).Comment: Revised version with new figure, footnotes and references adde
Leading nucleon and inelasticity in hadron-nucleus interactions
We present in this paper a calculation of the average proton-nucleus ine-
lasticity. Using an Iterative Leading Particle Model and the Glauber model, we
relate the leading particle distribution in nucleon-nucleus interactions with
the respective one in nucleon-proton collisions. To describe the leading
particle distribution in nucleon-proton collisions, we use the Regge-Mueller
formalism. To appear in Journal of Physics G.Comment: 11 pages, 2 figure
Nationalism, ethnicity and religion: Fundamental conflicts and the politics of identity in Tanzania
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