On the anomalous mass defect of strange stars in the Field Correlator Method

We investigate general aspects of the mass defects of strange stars in the context of the Field Correlator Method, without magnetic field. The main parameters of the model that enter the corresponding nonperturbative equation of state of the quark gluon plasma are the gluon condensate $G_2$ and the large distance static $Q{\bar Q}$ potential $V_1$. We calculate mass defects of stellar configurations in the central density range $11<\log\rho_c<18$. In general, the mass defects are strongly dependent on the model parameters. For a large range of values of $G_2$ and $V_1$, we obtain anomalous mass defects with magnitudes around $10^{53}\,$erg\,, of the same order of the observed energies of gamma-ray bursts and neutrino emissions in SN1987A, and of the theoretically predicted energies of the quark-novae explosions.Comment: 24 pages, 6 figure

Strange stars properties calculated in the framework of the Field Correlator Method

We calculate the strange star properties in the framework of the Field Correlator Method. We find that for the values of the gluon condensate $G_2=0.006\;{\rm GeV}^4$ and $G_2=0.0068\;{\rm GeV}^4$, which give a critical temperature $T_c\sim170\;{\rm MeV}$ at $\mu_c=0$, the sequences of strange stars are compatible with some of the semi-empirical mass-radius relations and data obtained from astrophysical observations.Comment: 26 pages, 10 figure

Low mass strange stars and the compact star 1E1207.4-5209 in the Field Correlator Method

We investigate the possible existence of anomalous mass defects in the low mass region of stellar sequences of strange stars. We employ the nonperturbative equation of state derived in the framework of the Field Correlator Method to describe the hydrostatic equilibrium of the strange matter. The large distance static $Q{\bar Q}$ potential $V_1$ and the gluon condensate $G_2$ are the main parameters of the model. We use the surface gravitational redshift measurements as a probe to determine the ratio $({\cal P}/{\cal E})_C$ at the center of strange stars. For $V_1=0$ and G_2\gappr0.035\,{\rm GeV}^4\,, we show that $({\cal P}/{\cal E})_C\simeq0.262$ and the corresponding redshift $z_S\simeq0.47$ are limiting values, at the maximum mass of the highest mass stellar sequence. As a direct application of our study, we try to determine the values of $V_1$ and $G_2$ from astrophysical observations of the compact star 1E\,1207.4-5209. Due to the uncertainties in the surface redshift determination, we made two attempts to obtain the model parameters. Our findings show that $({\cal P}/{\cal E})_C=0.073^{+0.029}_{+0.024}$\, at 68\% confidence, $V_1=0.44\pm0.10$\,GeV at 90\% confidence and $G_2=0.008\pm0.001\,{\rm GeV}^4$ at 95\% confidence \, in the first attempt; and $({\cal P}/{\cal E})_C=0.073^{+0.029}_{+0.024}=0.087\pm0.028$\, at 71\% confidence, $V_1=0.43\pm0.085$\,GeV at 94\% confidence and $G_2=0.0093\pm0.00092\,{\rm GeV}^4$ at 94\% confidence in the second attempt. These values of $V_1$ and $G_2$ are in reasonable agreement with the lattice and QCD sum rules calculations. As a consequence of the high values of $V_1$ and $G_2$, the anomalous mass defects of 1E\,1207.4-5209 are $|\Delta_2M|\simeq2.56\times10^{53}$\,erg\, in the first attempt and $|\Delta_2M|\simeq2.94\times10^{53}$\,erg\, in the second attempt.Comment: 34 pages, 15 figure

Enhanced Optical Dichroism of Graphene Nanoribbons

The optical conductivity of graphene nanoribbons is analytical and exactly derived. It is shown that the absence of translation invariance along the transverse direction allows considerable intra-band absorption in a narrow frequency window that varies with the ribbon width, and lies in the THz range domain for ribbons 10-100nm wide. In this spectral region the absorption anisotropy can be as high as two orders of magnitude, which renders the medium strongly dichroic, and allows for a very high degree of polarization (up to ~85) with just a single layer of graphene. The effect is resilient to level broadening of the ribbon spectrum potentially induced by disorder. Using a cavity for impedance enhancement, or a stack of few layer nanoribbons, these values can reach almost 100%. This opens a potential prospect of employing graphene ribbon structures as efficient polarizers in the far IR and THz frequencies.Comment: Revised version. 10 pages, 7 figure

New methodologies for the promotion of Geological Heritage using multimedia technology, 3D and augmented reality.

[Excerpt] The Internet and several hardware and software options that are currently available are very efficient ways for the promotion of geoparks, geoheritage and geosciences. The aim of this paper is to present a new and interactive way of gathering data into a website, based on several new web and photogrammetric technologies, applied to the Terras de Cavaleiros Global Geopark (Portugal). [...]info:eu-repo/semantics/publishedVersio

Características do herbicida S-Metolachlor nas culturas de milho e sorgo.

bitstream/CNPMS/16188/1/Circ_36.pd

Non universality of entanglement convertibility

Recently, it has been suggested that operational properties connected to quantum computation can be alternative indicators of quantum phase transitions. In this work we systematically study these operational properties in 1D systems that present phase transitions of different orders. For this purpose, we evaluate the local convertibility between bipartite ground states. Our results suggest that the operational properties, related to non-analyticities of the entanglement spectrum, are good detectors of explicit symmetries of the model, but not necessarily of phase transitions. We also show that thermodynamically equivalent phases, such as Luttinger liquids, may display different convertibility properties depending on the underlying microscopic model.Comment: 5 pages + references, 4 figures - improved versio