81 research outputs found
Can chaotic quantum energy levels statistics be characterized using information geometry and inference methods?
In this paper, we review our novel information geometrodynamical approach to
chaos (IGAC) on curved statistical manifolds and we emphasize the usefulness of
our information-geometrodynamical entropy (IGE) as an indicator of chaoticity
in a simple application. Furthermore, knowing that integrable and chaotic
quantum antiferromagnetic Ising chains are characterized by asymptotic
logarithmic and linear growths of their operator space entanglement entropies,
respectively, we apply our IGAC to present an alternative characterization of
such systems. Remarkably, we show that in the former case the IGE exhibits
asymptotic logarithmic growth while in the latter case the IGE exhibits
asymptotic linear growth. At this stage of its development, IGAC remains an
ambitious unifying information-geometric theoretical construct for the study of
chaotic dynamics with several unsolved problems. However, based on our recent
findings, we believe it could provide an interesting, innovative and
potentially powerful way to study and understand the very important and
challenging problems of classical and quantum chaos.Comment: 21 page
Variance of transmitted power in multichannel dissipative ergodic structures invariant under time reversal
We use random matrix theory (RMT) to study the first two moments of the wave
power transmitted in time reversal invariant systems having ergodic motion.
Dissipation is modeled by a number of loss channels of variable coupling
strength. To make a connection with ultrasonic experiments on ergodic
elastodynamic billiards, the channels injecting and collecting the waves are
assumed to be negligibly coupled to the medium, and to contribute essentially
no dissipation. Within the RMT model we calculate the quantities of interest
exactly, employing the supersymmetry technique. This approach is found to be
more accurate than another method based on simplifying naive assumptions for
the statistics of the eigenfrequencies and the eigenfunctions. The results of
the supersymmetric method are confirmed by Monte Carlo numerical simulation and
are used to reveal a possible source of the disagreement between the
predictions of the naive theory and ultrasonic measurements.Comment: 10 pages, 2 figure
Collectivity Embedded in Complex Spectra of Finite Interacting Fermi Systems: Nuclear Example
The mechanism of collectivity coexisting with chaos in a finite system of
strongly interacting fermions is investigated. The complex spectra are
represented in the basis of two-particle two-hole states describing the nuclear
double-charge exchange modes in Ca. An example of
excitations shows that the residual interaction, which generically implies
chaotic behavior, under certain specific and well identified conditions may
create strong transitions, even much stronger than those corresponding to a
pure mean-field picture. Such an effect results from correlations among the
off-diagonal matrix elements, is connected with locally reduced density of
states and a local minimum in the information entropy.Comment: 16 pages, LaTeX2e, REVTeX, 8 PostScript figures, to appear in
Physical Review
Analysis of symmetry breaking in quartz blocks using superstatistical random matrix theory
We study the symmetry breaking of acoustic resonances measured by Ellegaard
et al., Phys. Rev. Lett. 77, 4918 (1996), in quartz blocks. The observed
resonance spectra show a gradual transition from a superposition of two
uncoupled components, one for each symmetry realization, to a single component
well represented by a Gaussian orthogonal ensemble (GOE) of random matrices. We
discuss the applicability of superstatistical random-matrix theory to the final
stages of the symmetry breaking transition. A comparison is made between
different formula of the superstatistics and a pervious work [Abd El-Hady et
al, J. Phys. A: Math. Theor. 35, 2361 (2002)], which describes the same data by
introducing a third GOE component. Our results suggest that the
inverse-chi-square superstatistics could be used for studying the whole
symmetry breaking process.Comment: 11 pages, 1 figur
Inclusive pion double charge exchange on Oxygen(16) at 0.6-1.1 GeV
The inclusive pion double charge exchange (DCX) on oxygen nuclei has been
measured in the region where additional pion production is kinematically
forbidden. The experiment was performed at ITEP PS at incident pi- kinetic
energies T_0= 0.59, 0.75 and 1.1 GeV. The integrated forward differential cross
section was found to decrease with energy slowly. At 1.1 GeV it exceeds the
theoretical prediction within the conventional sequential single charge
exchange mechanism with a neutral pion in the intermediate state (Glauber
elastic rescattering) by about half an order of magnitude. The sequential
mechanism with two pions in the intermediate state (Glauber inelastic
rescatterings), which was proposed recently, seems to be able to explain the
observed slow energy dependence and allows to predict the DCX cross section for
higher energies.Comment: 27 pages, 13 figures. Minor corrections, one figure added. Accepted
in NP
Multiethnic meta-analysis identifies ancestry-specific and cross-ancestry loci for pulmonary function
Nearly 100 loci have been identified for pulmonary function, almost exclusively in studies of European ancestry populations. We extend previous research by meta-analyzing genome-wide association studies of 1000 Genomes imputed variants in relation to pulmonary function in a multiethnic population of 90,715 individuals of European (N = 60,552), African (N = 8429), Asian (N = 9959), and Hispanic/Latino (N = 11,775) ethnicities. We identify over 50 additional loci at genome-wide significance in ancestry-specific or multiethnic meta-analyses. Using recent fine-mapping methods incorporating functional annotation, gene expression, and differences in linkage disequilibrium between ethnicities, we further shed light on potential causal variants and genes at known and newly identified loci. Several of the novel genes encode proteins with predicted or established drug targets, including KCNK2 and CDK12. Our study highlights the utility of multiethnic and integrative genomics approaches to extend existing knowledge of the genetics of l
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