Completeness and Nonclassicality of Coherent States for Generalized Oscillator Algebras

The purposes of this work are (1) to show that the appropriate generalizations of the oscillator algebra permit the construction of a wide set of nonlinear coherent states in unified form; and (2) to clarify the likely contradiction between the nonclassical properties of such nonlinear coherent states and the possibility of finding a classical analog for them since they are P-represented by a delta function. In (1) we prove that a class of nonlinear coherent states can be constructed to satisfy a closure relation that is expressed uniquely in terms of the Meijer G-function. This property automatically defines the delta distribution as the P-representation of such states. Then, in principle, there must be a classical analog for them. Among other examples, we construct a family of nonlinear coherent states for a representation of the su(1,1) Lie algebra that is realized as a deformation of the oscillator algebra. In (2), we use a beam splitter to show that the nonlinear coherent states exhibit properties like anti-bunching that prohibit a classical description for them. We also show that these states lack second order coherence. That is, although the P-representation of the nonlinear coherent states is a delta function, they are not full coherent. Therefore, the systems associated with the generalized oscillator algebras cannot be considered `classical' in the context of the quantum theory of optical coherence.Comment: 26 pages, 10 figures, minor changes, misprints correcte

Spectroscopic search for binaries among EHB stars in globular clusters

We performed a spectroscopic search for binaries among hot Horizontal Branch stars in globular clusters. We present final results for a sample of 51 stars in NGC6752, and preliminary results for the first 15 stars analyzed in M80. The observed stars are distributed along all the HBs in the range 8000 < Teff < 32000 K, and have been observed during four nights. Radial velocity variations have been measured with the cross-correlation technique. We carefully analyzed the statistical and systematic errors associated with the measurements in order to evaluate the statistical significance of the observed variations. No close binary system has been detected, neither among cooler stars nor among the sample of hot EHB stars (18 stars with Teff > 22000 K in NGC6752). The data corrected for instrumental effects indicate that the radial velocity variations are always below the 3sigma level of ~15 km/s. These results are in sharp contrast with those found for field hot subdwarfs, and open new questions about the formation of EHB stars in globular clusters, and possibly of the field subdwarfs.Comment: To appear in Baltic Astronomy. Proceedings of the 2nd meeting on Hot Subdwarf Stars, La Palma, June 2005. 4 pages, 2 figure

A New Feature Along the Extended Blue Horizontal Branch of NGC 6752

In this letter we report on the detection of a new feature in the complex structure of the horizontal branch (HB) of the Galactic globular cluster NGC 6752. In the U vs. (U-V) plane, the HB shows a discontinuity (``jump'') at U-V ~= -1.0 (corresponding T_e ~ 23,000 K). This ``second U-jump'' adds to the u-jump identified by Grundahl et al. (1999) in a dozen of clusters at T_e ~ 11,500 K. We show that this new discontinuity might be due to the combination of post zero age HB evolution and diffusion effects. We identify 11 AGB-manque stars. The comparison between post-HB star counts and evolutionary lifetimes, as predicted by canonical stellar models, shows good agreement, at variance with similar estimates for NGC 6752 available in the literature.Comment: 13 pages, 3 figures, accepted by ApJ

Abundance anomalies in hot horizontal branch stars of the Galactic globular cluster NGC 2808

Astronomy and Astrophysics, 452, pp. 493-501, http://dx.doi.org./10.1051/0004-6361:20054593International audienc

Atmospheric-Pressure Non-thermal Plasma-JET effects on PS and PE surfaces

https://www.scopus.com/inward/record.url?eid=2-s2.0-84938125206&partnerID=40&md5=c2325a28f944e7e3e20b601b8d9a73efThe Atmospheric-Pressure Non-Thermal Plasma (APNTP) has become a topic of a great interest for a wide spectrum of applications in different industry branches, including the surface of treatment processes. In this work we evaluate the effect of an argon APNTP exposure to determine changes suffered by a polystyrene (PS) and polyethylene (PE) polymer surface through RAMAN spectroscopy and SEM. It was determined that the hydrophilic change in energetic terms, i.e. surface activation in the PS and PE polymers is addition of oxygen by surface activation when the samples with jet plasma are exposed with the inert argon gas. It was possible to characterize the hydrophilic shift based on the change in intensity of the spectra. © Published under licence by IOP Publishing Ltd.Ad Astra Rocket Company,Instituto Tecnologico de Costa Rica,International Atomic Energy Agency (IAEA),Universidad Nacional de Costa Ric

A new topological aspect of the arbitrary dimensional topological defects

We present a new generalized topological current in terms of the order parameter field $\vec \phi$ to describe the arbitrary dimensional topological defects. By virtue of the $$-mapping method, we show that the topological defects are generated from the zero points of the order parameter field $\vec \phi$, and the topological charges of these topological defects are topological quantized in terms of the Hopf indices and Brouwer degrees of $\phi$-mapping under the condition that the Jacobian $$. When $J(\frac \phi v)=0$, it is shown that there exist the crucial case of branch process. Based on the implicit function theorem and the Taylor expansion, we detail the bifurcation of generalized topological current and find different directions of the bifurcation. The arbitrary dimensional topological defects are found splitting or merging at the degenerate point of field function $\vec \phi$ but the total charge of the topological defects is still unchanged.Comment: 24 pages, 10 figures, Revte

Electromagnetic emission of white dwarf binary mergers

It has been recently proposed that the ejected matter from white dwarf (WD) binary mergers can produce transient, optical and infrared emission similar to the "kilonovae" of neutron star (NS) binary mergers. To confirm this we calculate the electromagnetic emission from WD-WD mergers and compare with kilonova observations. We simulate WD-WD mergers leading to a massive, fast rotating, highly magnetized WD with an adapted version of the smoothed-particle-hydrodynamics (SPH) code Phantom. We thus obtain initial conditions for the ejecta such as escape velocity, mass and initial position and distribution. The subsequent thermal and dynamical evolution of the ejecta is obtained by integrating the energy-conservation equation accounting for expansion cooling and a heating source given by the fallback accretion onto the newly-formed WD and its magneto-dipole radiation. We show that magnetospheric processes in the merger can lead to a prompt, short gamma-ray emission of up to $\approx 10^{46}$ erg in a timescale of $0.1$-$1$ s. The bulk of the ejecta initially expands non-relativistically with velocity $0.01 c$ and then it accelerates to $0.1 c$ due to the injection of fallback accretion energy. The ejecta become transparent at optical wavelengths around $\sim 7$ days post-merger with a luminosity $10^{41}$-$10^{42}$ erg s$^{-1}$. The X-ray emission from the fallback accretion becomes visible around $\sim 150$-$200$ day post-merger with a luminosity of $10^{39}$ erg s$^{-1}$. We also predict the post-merger time at which the central WD should appear as a pulsar depending on the value of the magnetic field and rotation period.Comment: 12 pages, Accepted for publication in JCA

Tratamiento quirúrgico de ptosis palpebral miogénica adquirida

Objective: To report the surgical outcome of aponeurosis surgery in patients with acquired myogenic eyelid ptosis and describe surgical guidelines for their correction. Methods: The clinical records of two patients with acquired myogenic eyelid ptosis after surgical correction were reviewed. Results: In two patients with acquired myogenic eyelid ptosis and barely good levator function, levator resection surgery was performed. Corneal complications appeared in both cases. Conclusion: Patients with acquired myogenic eyelid ptosis are at risk of post-operative surgical complications from corneal exposure. Surgical correction should be conservative and performed only when the visual axis is compromise

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Poor weather doesn’t dissuade voting in noncompetitive elections – not even Hurricane Sandy did in 2012

Rational choice theories of voter behavior suggest that factors such as bad weather and a busy schedule should discourage voting in noncompetitive elections. Considering voter turnout in New York City in 2012 – in the immediate aftermath of Hurricane Sandy – Viviana Rivera-Burgos, Narayani Lasala-Blanco and Robert Y. Shapiro find that personal motivation to vote can override minor and even major costs of voting, even in noncompetitive elections