Violation of multiparticle Bell inequalities for low- and high-flux parametric amplification using both vacuum and entangled input states

We show how polarization measurements on the output fields generated by parametric down conversion will reveal a violation of multiparticle Bell inequalities, in the regime of both low- and high-output intensity. In this case, each spatially separated system, upon which a measurement is performed, is comprised of more than one particle. In view of the formal analogy with spin systems, the proposal provides an opportunity to test the predictions of quantum mechanics for spatially separated higher spin states. Here the quantum behavior possible even where measurements are performed on systems of large quantum (particle) number may be demonstrated. Our proposal applies to both vacuum-state signal and idler inputs, and also to the quantum-injected parametric amplifier as studied by De Martini The effect of detector inefficiencies is included, and weaker Bell-Clauser-Horne inequalities are derived to enable realistic tests of local hidden variables with auxiliary assumptions for the multiparticle situation.

Studies on mosquitoes (Diptera: Culicidae) and anthropic environment: 1- Parity of blood seeking Anopheles (Kerteszia) in South-Eastern Brazil

Populations of Anopheles (Kerteszia) were sampled fortnightly over a one-year period (August 1991 to July 1992) at Ribeira Valley, S. Paulo State, Brazil. Indoor and outdoor collections were made on human bait at evening crepuscular period. The Polovodova technique for age grading was applied to 3,501 females of Anopheles cruzii and to 416 females of An. bellator. That sample represented 34.4% of the total number of mosquitoes collected. The most abundant species found was An. cruzii. However, An. bellator showed an endophagy that was almost three times greater than that of An. cruzii. The overall parous rate was 25.4% and uniparity was practically dominant one. A proportion of 26.9% of An. cruzii and 12.0% of An. bellator were found to be uniparous. Only three outdoor females of the former species (0.1%) showed biparity. Parity of An. cruzii was higher in females caught outdoors than in those caught indoors. Nevertheless, 497 nulliparous females examined (417 cruzii and 80 bellator) had ovaries that had advanced to Christophers and Mer stages III to V. These results imply that these females had already practised hematophagy. Relating these results to those from the parous females, a high statistical significance was found, leading to the conclusion that gonothophic discordance is a common pattern among these anophelines. Further, these results obtained with human bait catches strongly suggest that nearly 38.0% of these host-seeking females had already taken at least one previous blood-meal. So it is possible that enough time could thus be available for the plasmodian development in the vectors.

Studies on mosquitoes (Diptera: Culicidae) and anthropic environment: 11 - Biting activity and blood-seeking parity of Anopheles (Kerteszia) in South-Eastern Brazil

An. (Ker.) cruzii and An. (Ker.) bellator were monitored by the use of human bait and Shannon trap collections during a one-year period in 1994. Indoor and outdoor collections were made on human bait and inside the forest environment a Shannon trap was used. Both were undertaken in the evening crepuscular period. Results showed a greater abundance of An. cruzii in the forest, where as An. bellator was more abundant in the domiciliary environment. Through the application of the Polovodova method an age grading was established. Computing the parous and nulliparous females with Christopher's Stage III and above, more than 30.0% of blood-seeking specimens of both anophelines had had a previous blood meal. The higher abundance of An. bellator as compared with that of An. cruzii in the domiciliary environment may be explained by the influence of the neighboring low-lying coastal islands of the estuary system.

Leptonic CP violation

Several topics on CP violation in the lepton sector are reviewed. A few theoretical aspects concerning neutrino masses, leptonic mixing, and CP violation will be covered, with special emphasis on seesaw models. A discussion is provided on observable effects which are manifest in the presence of CP violation, particularly, in neutrino oscillations and neutrinoless double beta decay processes, and their possible implications in collider experiments such as the LHC. The role that leptonic CP violation may have played in the generation of the baryon asymmetry of the Universe through the mechanism of leptogenesis is also discussed.

Spontaneous leptonic CP violation and nonzero theta(13)

We consider a simple extension of the Standard Model by adding two Higgs triplets and a complex scalar singlet to its particle content. In this framework, the CP symmetry is spontaneously broken at high energies by the complex vacuum expectation value of the scalar singlet. Such a breaking leads to leptonic CP violation at low energies. The model also exhibits an A(4) X Z(4) flavor symmetry which, after being spontaneously broken at a high-energy scale, yields a tribimaximal pattern in the lepton sector. We consider small perturbations around the tribimaximal vacuum alignment condition in order to generate nonzero values of theta(13), as required by the latest neutrino oscillation data. It is shown that the value of theta(13) recently measured by the Daya Bay Reactor Neutrino Experiment can be accommodated in our framework together with large Dirac-type CP violation. We also address the viability of leptogenesis in our model through the out-of-equilibrium decays of the Higgs triplets. In particular, the CP asymmetries in the triplet decays into two leptons are computed and it is shown that the effective leptogenesis and low-energy CP-violating phases are directly linked.

A soft origin for CKM-type CP violation

We present a two-Higgs-doublet model, with a Z(3) symmetry, in which CP violation originates solely in a soft (dimension-2) coupling in the scalar potential, and reveals itself solely in the CKM (quark mixing) matrix. In particular, in the mass basis the Yukawa interactions of the neutral scalars are all real. The model has only eleven parameters to fit the six quark masses and the four independent CKM-matrix observables. We find regions of parameter space in which the flavour-changing neutral couplings are so suppressed that they allow the scalars to be no heavier than a few hundred GeV. (C) 2011 Elsevier B.V. All rights reserved.

Design and performance of a novel low-density parity-check code for distributed video coding

Low-density parity-check (LDPC) codes are nowadays one of the hottest topics in coding theory, notably due to their advantages in terms of bit error rate performance and low complexity. In order to exploit the potential of the Wyner-Ziv coding paradigm, practical distributed video coding (DVC) schemes should use powerful error correcting codes with near-capacity performance. In this paper, new ways to design LDPC codes for the DVC paradigm are proposed and studied. The new LDPC solutions rely on merging parity-check nodes, which corresponds to reduce the number of rows in the parity-check matrix. This allows to change gracefully the compression ratio of the source (DCT coefficient bitplane) according to the correlation between the original and the side information. The proposed LDPC codes reach a good performance for a wide range of source correlations and achieve a better RD performance when compared to the popular turbo codes.

A new bridge between leptonic CP violation and leptogenesis

Flavour effects due to lepton interactions in the early Universe may have played an important role in the generation of the cosmological baryon asymmetry through leptogenesis. If the only source of high-energy CP violation comes from the left-handed leptonic sector, then it is possible to establish a bridge between flavoured leptogenesis and low-energy leptonic CP violation. We explore this connection taking into account our present knowledge about low-energy neutrino parameters and the matter-antimatter asymmetry observed in the Universe. In this framework, we find that leptogenesis favours a hierarchical light neutrino mass spectrum, while for quasi-degenerate and inverted hierarchical neutrino masses there is a very narrow allowed window. The absolute neutrino mass scale turns out to be m less than or similar to 0.1 eV. (c) 2007 Elsevier B.V. All rights reserved.

Leptogenesis, CP violation and neutrino data: what can we learn?

A detailed analytic and numerical study of baryogenesis through leptogenesis is performed in the framework of the standard model of electroweak interactions extended by the addition of three right-handed neutrinos, leading to the seesaw mechanism. We analyze the connection between GUT-motivated relations for the quark and lepton mass matrices and the possibility of obtaining a viable leptogenesis scenario. In particular, we analyze whether the constraints imposed by SO(10) GUTs can be compatible with all the available solar, atmospheric and reactor neutrino data and, simultaneously, be capable of producing the required baryon asymmetry via the leptogenesis mechanism. It is found that the Just-So(2) and SMA solar solutions lead to a viable leptogenesis even for the simplest SO(10) GUT, while the LMA, LOW and VO solar solutions would require a different hierarchy for the Dirac neutrino masses in order to generate the observed baryon asymmetry. Some implications on CP violation at low energies and on neutrinoless double beta decay are also considered. (C) 2002 Elsevier Science B.V. All rights reserved.

Radiatively induced Lorentz and CPT violation in Schwinger constant field approximation

The Schwinger proper-time method is an effective calculation method, explicitly gauge-invariant and nonperturbative. We make use of this method to investigate the radiatively induced Lorentz- and CPT-violating effects in quantum electrodynamics when an axial-vector interaction term is introduced in the fermionic sector. The induced Lorentz- and CPT-violating Chern-Simons term coincides with the one obtained using a covariant derivative expansion but differs from the result usually obtained in other regularization schemes. A possible ambiguity in the approach is also discussed. (C) 2001 Published by Elsevier Science B.V.

Stability of the tree-level vacuum in two Higgs doublet models against charge or CP spontaneous violation

We show that in two Higgs doublet models at tree-level the potential minimum preserving electric charge and CP symmetries, when it exists, is the global one. Furthermore, we derived a very simple condition, involving only the coefficients of the quartic terms of the potential, that guarantees spontaneous CP breaking. (C) 2004 Elsevier B.V. All rights reserved.

Undoubtable signs of CP-violation in Higgs decays at the LHC run 2

With the discovery of the Higgs boson at the Large Hadron Collider the high energy physics community's attention has now turned to understanding the properties of the Higgs boson, together with the hope of finding more scalars during run 2. In this work we discuss scenarios where using a combination of three decays, involving the 125 GeV Higgs boson, the Z boson and at least one more scalar, an indisputable signal of CP-violation arises. We use a complex two-Higgs doublet model as a reference model and present some benchmark points that have passed all current experimental and theoretical constraints, and that have cross sections large enough to be probed during run 2.

Covered interest parity

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and Economics

Risk parity: True versus naive approach

This paper studies the performance of two different Risk Parity strategies, one from Maillard (2008) and a “naïve” that was already used by market practitioners, against traditional strategies. The tests will compare different regions (US, UK, Germany and Japan) since 1991 to 2013, and will use different ways of volatility. The main findings are that Risk Parity outperforms any traditional strategy, and the “true” (by Maillard) has considerable better results than the “naïve” when using historical volatility, while using EWMA there are significant differences.