1,237 research outputs found
Spinodal instabilities within BUU approach
Using a recently developed method for the inclusion of fluctuation in the BUU
dynamics, we study the self-consistent propagation of inherent thermal noise of
unstable nuclear matter. The large time behaviour of the evolving system
exhibits synergism between fluctuation and non-linearities in a universal
manner which manifest in the appearance of macroscopic structure in the average
description.Comment: 12 pages Revtex. Two figures, uuencoded, are enclosed in a separate
fil
Hybrid neutron stars within the Nambu-Jona-Lasinio model and confinement
Recently, it has been shown that the standard Nambu-Jona-Lasinio (NJL) model
is not able to reproduce the correct QCD behavior of the gap equation at large
density, and therefore a different cutoff procedure at large momenta has ben
proposed. We found that, even with this density dependent cutoff procedure, the
pure quark phase in neutron stars (NS) interiors is unstable, and we argue that
this could be related to the lack of confinement in the original NJL model.Comment: 2 pages, 1 figure, to be published in the proceedings of the
conference EXOCT07, Catania, 11-15 June, 200
A holistic multimodal approach to the non-invasive analysis of watercolour paintings
A holistic approach using non-invasive multimodal imaging and spectroscopic techniques to study the materials (pigments, drawing materials and paper) and painting techniques of watercolour paintings is presented. The non-invasive imaging and spectroscopic techniques include VIS-NIR reflectance spectroscopy and multispectral imaging, micro-Raman spectroscopy, X-ray fluorescence spectroscopy (XRF) and optical coherence tomography (OCT). The three spectroscopic techniques complement each other in pigment identification. Multispectral imaging (near infrared bands), OCT and micro-Raman complement each other in the visualisation and identification of the drawing material. OCT probes the microstructure and light scattering properties of the substrate while XRF detects the elemental composition that indicates the sizing methods and the filler content . The multiple techniques were applied in a study of forty six 19th century Chinese export watercolours from the Victoria & Albert Museum (V&A) and the Royal Horticultural Society (RHS) to examine to what extent the non-invasive analysis techniques employed complement each other and how much useful information about the paintings can be extracted to address art conservation and history questions
A Dynamical Model of Color Confinement
A dynamical model of confinement based on a transport theoretical description
of the Friedberg-Lee model is extended to explicit color degrees of freedom.
The string tension is reproduced by an adiabatic string formation from the
nucleon ground state. Color isovector oscillation modes of a -system
are investigated for a wide range of relative -momenta and the
dynamical impact of color confinement on the quark motion is shown.Comment: 12 pages plus 5 figure
The Equation of State of Dense Matter : from Nuclear Collisions to Neutron Stars
The Equation of State (EoS) of dense matter represents a central issue in the
study of compact astrophysical objects and heavy ion reactions at intermediate
and relativistic energies. We have derived a nuclear EoS with nucleons and
hyperons within the Brueckner-Hartree-Fock approach, and joined it with quark
matter EoS. For that, we have employed the MIT bag model, as well as the
Nambu--Jona-Lasinio (NJL) and the Color Dielectric (CD) models, and found that
the NS maximum masses are not larger than 1.7 solar masses. A comparison with
available data supports the idea that dense matter EoS should be soft at low
density and quite stiff at high density.Comment: 8 pages, 5 figures, invited talk given at NPA3, Dresden, March 200
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