2,886 research outputs found
Signatures of Dark Matter in Cosmic-Ray Observations
I provide a short review of the current status of indirect dark matter
searches with gamma rays, charged cosmic rays and neutrinos. For each case I
will focus on various excesses reported in the literature which have been
interpreted as possible hints of dark matter, and I will use them as examples
to discuss theoretical aspects and analysis methodologies.Comment: 8 pages, 2 figures, contribution to the proceedings of the 16th TAUP
conference, Sept. 9-13 2019, Toyama, Japa
Phenomenological model for magnetotransport in a multi-orbital system
By means of the Boltzmann equation, we have calculated some magnetotransport
quantities for the layered multi-orbital compound SrRuO. The Hall
coefficient, the magnetoresistance and the in-plane resistivity have been
determined taking into account the Fermi surface curvature and different time
collisions for the electrons in the bands. A consistent explanation of
the experimental results has been obtained assuming different relaxation rates
for the in-plane transport with and without an applied magnetic field,
respectively.Comment: 4 pages, 3 Figure; to appear in Phys. Rev.
Image-based deep learning for classification of noise transients in gravitational wave detectors
The detection of gravitational waves has inaugurated the era of gravitational
astronomy and opened new avenues for the multimessenger study of cosmic
sources. Thanks to their sensitivity, the Advanced LIGO and Advanced Virgo
interferometers will probe a much larger volume of space and expand the
capability of discovering new gravitational wave emitters. The characterization
of these detectors is a primary task in order to recognize the main sources of
noise and optimize the sensitivity of interferometers. Glitches are transient
noise events that can impact the data quality of the interferometers and their
classification is an important task for detector characterization. Deep
learning techniques are a promising tool for the recognition and classification
of glitches. We present a classification pipeline that exploits convolutional
neural networks to classify glitches starting from their time-frequency
evolution represented as images. We evaluated the classification accuracy on
simulated glitches, showing that the proposed algorithm can automatically
classify glitches on very fast timescales and with high accuracy, thus
providing a promising tool for online detector characterization.Comment: 25 pages, 8 figures, accepted for publication in Classical and
Quantum Gravit
Secondary radiation from the Pamela/ATIC excess and relevance for Fermi
The excess of electrons/positrons observed by the Pamela and ATIC experiments
gives rise to a noticeable amount of synchrotron and Inverse Compton Scattering
(ICS) radiation when the e^+e^- interact with the Galactic Magnetic Field, and
the InterStellar Radiation Field (ISRF). In particular, the ICS signal produced
within the WIMP annihilation interpretation of the Pamela/ATIC excess shows
already some tension with the EGRET data. On the other hand, 1 yr of Fermi data
taking will be enough to rule out or confirm this scenario with a high
confidence level. The ICS radiation produces a peculiar and clean "ICS Haze"
feature, as well, which can be used to discriminate between the astrophysical
and Dark Matter scenarios. This ICS signature is very prominent even several
degrees away from the galactic center, and it is thus a very robust prediction
with respect to the choice of the DM profile and the uncertainties in the ISRF.Comment: 5 pages, 3 figures; v2: improved figures, enlarged discussion on the
gamma signal and data; to appear in ApJ
Curvature-induced Rashba spin-orbit interaction in strain-driven nanostructures
We derive the effective dimensionally reduced Schr\"odinger equation with
spin-orbit interaction in low-dimensional electronic strain driven
nanostructures. A method of adiabatic separation among fast normal quantum
degrees of freedom and slow tangential quantum degrees of freedom is used to
show the emergence of a strain-induced Rashba-like spin-orbit interaction
(SOI). By applying this analysis to one-dimensional curved quantum wires we
demonstrate that the curvature-induced Rashba SOI leads to enhanced spin-orbit
effects.Comment: 5 pages, 3 figures, to be published in SPIN (World Scientific) as
Topical Issue on Functional Nanomembrane
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