17,012 research outputs found
Education, Gender and Youth in the labor market in Argentina
The main goal of this paper is to show the importance of secondary education in the results of Argentine youth in the labor market, both empirically and with existing data, and differentiating impacts by gender. The evidence suggests that secondary education promotes greater participation in the labor force and it does so in a higher degree among young women than young men. Also, compared with primary education, secondary school increases the employment opportunity of youth and has a positive effect on remuneration for both gender, but effect is more positive among boys than among girls.
Decoherence induced by a chaotic environment: A quantum walker with a complex coin
We study the differences between the process of decoherence induced by
chaotic and regular environments. For this we analyze a family of simple models
wich contain both regular and chaotic environments. In all cases the system of
interest is a "quantum walker", i.e. a quantum particle that can move on a
lattice with a finite number of sites. The walker interacts with an environment
wich has a D dimensional Hilbert space. The results we obtain suggest that
regular and chaotic environments are not distinguishable from each other in a
(short) timescale t*, wich scales with the dimensionality of the environment as
t*~log(D). Howeber, chaotic environments continue to be effective over
exponentially longer timescales while regular environments tend to reach
saturation much sooner. We present both numerical and analytical results
supporting this conclusion. The family of chaotic evolutions we consider
includes the so-called quantum multi-baker-map as a particular case.Comment: 7 pages, 8 figure
A General Transfer-Function Approach to Noise Filtering in Open-Loop Quantum Control
We present a general transfer-function approach to noise filtering in
open-loop Hamiltonian engineering protocols for open quantum systems. We show
how to identify a computationally tractable set of fundamental filter
functions, out of which arbitrary transfer filter functions may be assembled up
to arbitrary high order in principle. Besides avoiding the infinite recursive
hierarchy of filter functions that arises in general control scenarios, this
fundamental filter-functions set suffices to characterize the error suppression
capabilities of the control protocol in both the time and frequency domain. We
prove that the resulting notion of filtering order reveals conceptually
distinct, albeit complementary, features of the controlled dynamics as compared
to the order of error cancellation, traditionally defined in the Magnus sense.
Examples and implications are discussed.Comment: Paper plus supplementary material. 10 pages, 1 figure. Unnumbered
equation between 2 and 3 corrected. Results are unchange
Decoherence induced by a dynamic spin environment (II): Disentanglement by local system-environment interactions
This article studies the decoherence induced on a system of two qubits by
local interactions with a spin chain with nontrivial internal dynamics
(governed by an XY Hamiltonian). Special attention is payed to the transition
between two limits: one in which both qubits interact with the same site of the
chain and another one where they interact with distant sites. The two cases
exhibit different behaviours in the weak and strong coupling regimes: when the
coupling is weak it is found that decoherence tends to decrease with distance,
while for strong coupling the result is the opposite. Also, in the weak
coupling case, the long distance limit is rapidly reached, while for strong
coupling there is clear evidence of an expected effect: environment-induced
interactions between the qubits of the system. A consequence of this is the
appearance of quasiperiodic events that can be interpreted as ``sudden deaths''
and ``sudden revivals'' of the entanglement between the qubits, with a time
scale related to the distance between them.Comment: 10 pages, 9 figure
Palomar/Las Campanas Imaging Atlas of Blue Compact Dwarf Galaxies: II. Surface Photometry and the Properties of the Underlying Stellar Population
We present the results from an analysis of surface photometry of B, R, and
Halpha images of a total of 114 nearby galaxies drawn from the Palomar/Las
Campanas Imaging Atlas of Blue Compact Dwarf galaxies. Surface brightness and
color profiles for the complete sample have been obtained. We determine the
exponential and Sersic profiles that best fit the surface brightness
distribution of the underlying stellar population detected in these galaxies.
We also compute the (B-R) color and total absolute magnitude of the underlying
stellar population and compared them to the integrated properties of the
galaxies in the sample. Our analysis shows that the (B-R) color of the
underlying population is systematically redder than the integrated color,
except in those galaxies where the integrated colors are strongly contaminated
by line and nebular-continuum emission. We also find that galaxies with
relatively red underlying stellar populations (typically (B-R)>~1mag) show
structural properties compatible with those of dwarf elliptical galaxies (i.e.
a smooth light distribution, fainter extrapolated central surface brightness
and larger scale lengths than BCD galaxies with blue underlying stellar
populations). At least ~15% of the galaxies in the sample are compatible with
being dwarf elliptical (dE) galaxies experiencing a burst of star formation.
For the remaining BCD galaxies in the sample we do not find any correlation
between the recent star formation activity and their structural differences
with respect to other types of dwarf galaxies.Comment: 35 pages, 6 figures, accepted for publication in ApJS. Postscript
files of panels f1a-f1o of figure 1 are available online at
http://www.ociw.edu/~agpaz/astro-ph/apjs2004
Total correlations as fully additive entanglement monotones
We generalize the strategy presented in Refs. [1, 2], and propose general
conditions for a measure of total correlations to be an entanglement monotone
using its pure (and mixed) convex-roof extension. In so doing, we derive
crucial theorems and propose a concrete candidate for a total correlations
measure which is a fully additive entanglement monotone.Comment: 8 pages, 3 figures. Title changed, new result
Global velocity field and bubbles in the BCD Mrk86
We have studied the velocity field of the Blue Compact Dwarf galaxy Mrk86
(NGC2537) using data provided by 14 long-slit optical spectra. This kinematical
information is complemented with narrow-band ([OIII]5007A and Halpha) and
broad-band (B, V, Gunn-r and K) imaging. The analysis of the galaxy global
velocity field suggests that the ionized gas could be distributed in a rotating
inclined disk, with projected central angular velocity of Omega=34 km/s/kpc.
The comparison between the stellar, HI and modeled dark matter density profile,
indicates that the total mass within its optical radius is dominated by the
stellar component. Peculiarities observed in its velocity field can be
explained by irregularities in the ionized gas distribution or local motions
induced by star formation. Kinematical evidences for two expanding bubbles,
Mrk86-B and Mrk86-C, are given. They show expanding velocities of 34 km/s and
17 km/s, Halpha luminosities of 3x10^38 erg/s and 1.7x10^39 erg/s, and physical
radii of 374 and 120 pc, respectively. The change in the [SII]/Halpha,
[NII]/Halpha, [OII]/[OIII] and [OIII]/Hbeta line ratios with the distance to
the bubble precursor suggests a diminution in the ionization parameter and, in
the case of Mrk86-B, an enhancement of the shock-excited gas emission. The
optical-near-infrared colours of the bubble precursors are characteristic of
low metallicity star forming regions (0.2 Zsun) with burst strengths of about 1
per cent in mass.Comment: 14 pages, 12 PostScript figures, accepted for publication in MNRAS,
also available at ftp://cutrex.fis.ucm.es/pub/OUT/gil/PAPERS
Measuring work and heat in ultracold quantum gases
We propose a feasible experimental scheme to direct measure heat and work in
cold atomic setups. The method is based on a recent proposal which shows that
work is a positive operator valued measure (POVM). In the present contribution,
we demonstrate that the interaction between the atoms and the light
polarisation of a probe laser allows us to implement such POVM. In this way the
work done on or extracted from the atoms after a given process is encoded in
the light quadrature that can be measured with a standard homodyne detection.
The protocol allows one to verify fluctuation theorems and study properties of
the non-unitary dynamics of a given thermodynamic process.Comment: Published version in the Focus Issue on "Quantum Thermodynamics
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