4,937 research outputs found
Decoherence and entropy of primordial fluctuations II. The entropy budget
We calculate the entropy of adiabatic perturbations associated with a
truncation of the hierarchy of Green functions at the first non trivial level,
i.e. in a self-consistent Gaussian approximation. We give the equation
governing the entropy growth and discuss its phenomenology. It is parameterized
by two model-dependent kernels. We then examine two particular inflationary
models, one with isocurvature perturbations, the other with corrections due to
loops of matter fields. In the first model the entropy grows rapidely, while in
the second the state remains pure (at one loop).Comment: 28 page
High-intensity cyclotron for the IsoDAR experiment
The IsoDAR experiment is the MIT proposal to investigate about several neutrino properties, in order to explain some anomalies experimentally observed. It requires 10mA of proton beam at the energy of 60MeV to produce a high-intensity electron antineutrino flux from the production and the decay of 8Li: it is an ambitious goal for the accelerator design, due also to the fact that the machine
has to be placed near a neutrino detector, like KAMLAND or WATCHMAN, located in underground sites. A compact cyclotron able to accelerate H+2 molecule beam up to energy of 60 MeV/amu is under study. The critical issues of this machine
concern the beam injection due to the effects of space charge, the efficiency of the beam extraction and the technical solutions needed to the machine assembly. Here,
the innovative solutions and the preliminary results achieved by the IsoDAR team are discussed
Multiresolution analysis (discrete wavelet transform) through Daubechies family for emotion recognition in speech
We propose a study of the mathematical properties of voice as an audio signal -- This work includes signals in which the channel conditions are not ideal for emotion recognition -- Multiresolution analysis- discrete wavelet transform – was performed through the use of Daubechies Wavelet Family (Db1-Haar, Db6, Db8, Db10) allowing the decomposition of the initial audio signal into sets of coefficients on which a set of features was extracted and analyzed statistically in order to differentiate emotional states -- ANNs proved to be a system that allows an appropriate classification of such states -- This study shows that the extracted features using wavelet decomposition are enough to analyze and extract emotional content in audio signals presenting a high accuracy rate in classification of emotional states without the need to use other kinds of classical frequency-time features -- Accordingly, this paper seeks to characterize mathematically the six basic emotions in humans: boredom, disgust, happiness, anxiety, anger and sadness, also included the neutrality, for a total of seven states to identify20th Argentinean Bioengineering Society Congress, SABI 2015 (XX Congreso Argentino de BioingenierĂa y IX Jornadas de IngenierĂa ClĂnica)28–30 October 2015, San Nicolás de los Arroyos, Argentin
Stability of spinor Fermi gases in tight waveguides
The two and three-body correlation functions of the ground state of an
optically trapped ultracold spin-1/2 Fermi gas (SFG) in a tight waveguide (1D
regime) are calculated in the plane of even and odd-wave coupling constants,
assuming a 1D attractive zero-range odd-wave interaction induced by a 3D p-wave
Feshbach resonance, as well as the usual repulsive zero-range even-wave
interaction stemming from 3D s-wave scattering. The calculations are based on
the exact mapping from the SFG to a ``Lieb-Liniger-Heisenberg'' model with
delta-function repulsions depending on isotropic Heisenberg spin-spin
interactions, and indicate that the SFG should be stable against three-body
recombination in a large region of the coupling constant plane encompassing
parts of both the ferromagnetic and antiferromagnetic phases. However, the
limiting case of the fermionic Tonks-Girardeau gas (FTG), a spin-aligned 1D
Fermi gas with infinitely attractive p-wave interactions, is unstable in this
sense. Effects due to the dipolar interaction and a Zeeman term due to a
resonance-generating magnetic field do not lead to shrinkage of the region of
stability of the SFG.Comment: 5 pages, 6 figure
R^2-corrections to Chaotic Inflation
Scalar density cosmological perturbations, spectral indices and reheating in
a chaotic inflationary universe model, in which a higher derivative term is
added, are investigated. This term is supposed to play an important role in the
early evolution of the Universe, specifically at times closer to the Planck
era.Comment: 14 pages, accepted for publication in MPL
Autopia's End: The Decline and Fall of Detroit's Automotive Manufacturing Landscape
Since the 1980s, Detroit’s once- monumental building stock of historic automotive manufacturing facilities has mostly disappeared. Demolition, redevelopment, and abandonment have left little to mark the city’s twentieth-century history as the world capital of the automobile industry. Planning and policymaking have been complicit through publicly subsidizing destructive redevelopment and by failing to argue for retention or preservation. Even today the city calls for the demolition of one of its last remaining historic auto factories. This paper surveys the disappearance of Detroit’s auto factories, and documents the histories of three of the largest complexes: the Chrysler-Chalmers Plant, cleared for a redeveloped factory; the Cadillac Plant, cleared for a failed economic development project; and the Packard Plant, slowly abandoned over 60 years. The paper calls for a revised theory and practice of preservation that accommodates the weak markets, imperfect condition, and informal uses that characterize abandoned industrial buildings in shrinking cities
Diffraction in time of a confined particle and its Bohmian paths
Diffraction in time of a particle confined in a box which its walls are
removed suddenly at is studied. The solution of the time-dependent
Schr\"{o}dinger equation is discussed analytically and numerically for various
initial wavefunctions. In each case Bohmian trajectories of the particles are
computed and also the mean arrival time at a given location is studied as a
function of the initial state.Comment: 8 pages, 6 figure
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