9,780 research outputs found
Incoherent Mollow triplet
A counterpart of the Mollow triplet (luminescence lineshape of a two-level
system under coherent excitation) is obtained for the case of incoherent
excitation in a cavity. Its analytical expression, in excellent agreement with
numerical results, pinpoints analogies and differences between the conventional
resonance fluorescence spectrum and its cavity QED analogue under incoherent
excitation.Comment: 4 pages, 3 figure
Quantitative Description of Strong-Coupling of Quantum Dots in Microcavities
We have recently developed a self-consistent theory of Strong-Coupling in the
presence of an incoherent pumping [arXiv:0807.3194] and shown how it could
reproduce quantitatively the experimental data [PRL 101, 083601 (2008)]. Here,
we summarize our main results, provide the detailed analysis of the fitting of
the experiment and discuss how the field should now evolve beyond merely
qualitative expectations, that could well be erroneous even when they seem to
be firmly established.Comment: Submitted to the AIP Conference Proceedings Series for the ICPS 2008
(Rio de Janeiro). 2 pages, reduced-quality figur
Electrostatic control of quantum dot entanglement induced by coupling to external reservoirs
We propose a quantum transport experiment to prepare and measure
charge-entanglement between two electrostatically defined quantum dots.
Coherent population trapping, as realized in cavity quantum electrodynamics,
can be carried out by using a third quantum dot to play the role of the optical
cavity. In our proposal, a pumping which is quantum mechanically
indistinguishable for the quantum dots drives the system into a state with a
high degree of entanglement. The whole effect can be switched on and off by
means of a gate potential allowing both state preparation and entanglement
detection by simply measuring the total current.Comment: 5 pages, 4 figures, Latex2e with EPL macros, to appear in Europhysics
Letter
Lasing in Strong Coupling
An almost ideal thresholdless laser can be realized in the strong-coupling
regime of light-matter interaction, with Poissonian fluctuations of the field
at all pumping powers and all intensities of the field. This ideal scenario is
thwarted by quantum nonlinearities when crossing from the linear to the
stimulated emission regime, resulting in a universal jump in the second order
coherence, which measurement could however be used to establish a standard of
lasing in strong coupling.Comment: 5 pages, 2 figure
Optimization of photon correlations by frequency filtering
Photon correlations are a cornerstone of Quantum Optics. Recent works [NJP 15
025019, 033036 (2013), PRA 90 052111 (2014)] have shown that by keeping track
of the frequency of the photons, rich landscapes of correlations are revealed.
Stronger correlations are usually found where the system emission is weak.
Here, we characterize both the strength and signal of such correlations,
through the introduction of the 'frequency resolved Mandel parameter'. We study
a plethora of nonlinear quantum systems, showing how one can substantially
optimize correlations by combining parameters such as pumping, filtering
windows and time delay.Comment: Small updates to take into account the recent experimental
observation of the physics here analyze
A model for assembly sequence planning in a multirobot environment
2002 IFAC15th Triennial World Congress, Barcelona, SpainThis paper presents a model for the selection of optimal assembly sequences for a product in multirobot systems. The objective of the plan is the minimization of the total assembly time (makespan). To meet this objective, the model takes into account, in addition to the assembly times and resources for each task, the times needed to change tools in the robots, and the delays due to the transportation of intermediate subassemblies between different machines. An A* algorithm that solves the problem is also presented, which starts from the And/Or graph for the product (compressed representation of all feasible assembly plans)
Heavy Neutrinos and Lepton Flavour Violation in Left-Right Symmetric Models at the LHC
We discuss lepton flavour violating processes induced in the production and
decay of heavy right-handed neutrinos at the LHC. Such particles appear in
left-right symmetrical extensions of the Standard Model as the messengers of
neutrino mass generation, and can have masses at the TeV scale. We determine
the expected sensitivity on the right-handed neutrino mixing matrix, as well as
on the right-handed gauge boson and heavy neutrino masses. By comparing the
sensitivity of the LHC with that of searches for low energy LFV processes, we
identify favourable areas of the parameter space to explore the complementarity
between LFV at low and high energies.Comment: 34 pages, 16 figures, PRD versio
Current trends, figures and challenges in out of home child care: An international comparative analysis
AbstractThis article closes the special issue of this journal about an international review of out-of-home child care, principally family foster care and residential care, tough several aspects related to adoption were included as well. Although a comparison on some data about residential and foster care, or kinship and non-kinship care, is carried out, the article tries above all to make a reflection on the implications of several themes that have emerged as more interesting or important. Matters such as the use of residential care and its role in the current child care system, the overrepresentation of ethnic minorities in foster care in several countries, the situation of unaccompanied young people asylum seeking, the use of adoption as a permanent solution, the challenges of the transition to the adulthood from care, the relevance of the professionalization and models based on social pedagogy, the evaluation and planning based on data, and the current financial crisis and its impact on child care systems are some of the remarkable topics that will be reviewed
Production and decays of supersymmetric Higgs bosons in spontaneously broken R-parity
We study the mass spectra, production and decay properties of the lightest
supersymmetric CP-even and CP-odd Higgs bosons in models with spontaneously
broken R-parity (SBRP). We compare the resulting mass spectra with expectations
of the Minimal Supersymmetric Standard Model (MSSM), stressing that the model
obeys the upper bound on the lightest CP-even Higgs boson mass. We discuss how
the presence of the additional scalar singlet states affects the Higgs
production cross sections, both for the Bjorken process and the "associated
production". The main phenomenological novelty with respect to the MSSM comes
from the fact that the spontaneous breaking of lepton number leads to the
existence of the majoron, denoted J, which opens new decay channels for
supersymmetric Higgs bosons. We find that the invisible decays of CP-even
Higgses can be dominant, while those of the CP-odd bosons may also be sizeable.Comment: 21 pages, 8 figures; minor changes, final version for publicatio
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