1,906 research outputs found
Quantum correlations and classical resonances in an open chaotic system
We show that the autocorrelation of quantum spectra of an open chaotic system
is well described by the classical Ruelle-Pollicott resonances of the
associated chaotic strange repeller. This correspondence is demonstrated
utilizing microwave experiments on 2-D n-disk billiard geometries, by
determination of the wave-vector autocorrelation C(\kappa) from the
experimental quantum spectra S_{21}(k). The correspondence is also established
via "numerical experiments" that simulate S_{21}(k) and C(\kappa) using
periodic orbit calculations of the quantum and classical resonances.
Semiclassical arguments that relate quantum and classical correlation functions
in terms of fluctuations of the density of states and correlations of particle
density are also examined and support the experimental results. The results
establish a correspondence between quantum spectral correlations and classical
decay modes in an open systems.Comment: 10 pages, 5 eps figures, "Quantum chaos Y2K" Nobel symposium, to
appear in Physica Script
Acoustical-Mode-Driven Electron-Phonon Coupling in Transition-Metal Diborides
We show that the electron-phonon coupling in the transition-metal diborides
NbB2 and TaB2 is dominated by the longitudinal acoustical (LA) mode, in
contrast to the optical E_{2g} mode dominated coupling in MgB2. Our ab initio
results, described in terms of phonon dispersion, linewidth, and partial
electron-phonon coupling along Gamma to A, also show that (i) NbB2 and TaB2
have a relatively weak electron-phonon coupling, (ii) the E_{2g} linewidth is
an order of magnitude larger in MgB2 than in NbB2 or TaB2, (iii) the E_{2g}
frequency in NbB2 and TaB2 is considerably higher than in MgB2, and (iv) the LA
frequency at A for TaB2 is almost half of that of MgB2 or NbB2.Comment: 4 pages, 4 figures, and 1 tabl
Ed-Fed: A generic federated learning framework with resource-aware client selection for edge devices
Federated learning (FL) has evolved as a prominent method for edge devices to
cooperatively create a unified prediction model while securing their sensitive
training data local to the device. Despite the existence of numerous research
frameworks for simulating FL algorithms, they do not facilitate comprehensive
deployment for automatic speech recognition tasks on heterogeneous edge
devices. This is where Ed-Fed, a comprehensive and generic FL framework, comes
in as a foundation for future practical FL system research. We also propose a
novel resource-aware client selection algorithm to optimise the waiting time in
the FL settings. We show that our approach can handle the straggler devices and
dynamically set the training time for the selected devices in a round. Our
evaluation has shown that the proposed approach significantly optimises waiting
time in FL compared to conventional random client selection methods
Petrology and geochemitstry of late Archaean granitoids in the northern part of EDC, Southern India: implications for transitional geodynamic setting
The results of field, petrographic and geochemical work of the granitoids of Hutti-Gurgunta area in the northern part of Eastern Dharwar Craton (EDC) is presented in this paper. This crustal section comprises polyphase banded to foliated TTG gneisses, middle amphibolite facies Gurgunta schist belt and upper greenschist facies Hutti schist belt and abundant granite plutons. The focus of the present study is mainly on basement TTG gneisses and a granite pluton (∼ 240 sq km areal extent), to discuss crustal accretion processes including changing petrogenetic mechanism and geodynamic setting. The TTGs contain quartz, plagioclase, lesser K-feldspar and hornblende with minor biotite while the granite contain quartz, plagioclase, K-feldspar and hornblende. Late stage alteration (chloritisation, sericitisation and epidotisation) is wide spread in the entire area. A huge synplutonic mafic body which is dioritic to meladioritic in composition injects the granite and displays all stages of progressive mixing and hybridization. The studied TTGs and granite show distinct major and trace element patterns. The TTGs are characterized by higher SiO2, high Al2O3, and Na2O, low TiO2, Mg#, CaO, K2O and LILE, and HFS elements compared to granite. TTGs define strong trondhjemite trend whilst granite shows calc-alkaline trend. However, both TTGs and granite show characteristics of Phanerozoic high-silica adakites. The granite also shows characteristics of transitional TTGs in its high LILE, and progressive increase in K2O with differentiation. Both TTGs and granite define linear to sub-linear trends on variation diagrams. The TTGs show moderate total REE contents with fractionated REE patterns (La/YbN =17.73–61.73) and slight positive or without any significant Eu anomaly implying little amount of amphibole or plagioclase in residual liquid. On the other hand, the granite displays poor to moderate fractionation of REE patterns (La/YbN = 9.06–67.21) without any significant Eu anomaly. The TTGs have been interpreted to be produced by low-K basaltic slab melting at shallow depth, whereas the granite pluton has been formed by slab melting at depth and these melts interacted with peridotite mantle wedge. Such changing petrogenetic mechanisms and geodynamic conditions explain increase in the contents of MgO, CaO, Ni and Cr from 2700 Ma to 2500 Ma granitoids in the EDC
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