4,304 research outputs found
Neutron matter under strong magnetic fields: a comparison of models
The equation of state of neutron matter is affected by the presence of a
magnetic field due to the intrinsic magnetic moment of the neutron. Here we
study the equilibrium configuration of this system for a wide range of
densities, temperatures and magnetic fields. Special attention is paid to the
behavior of the isothermal compressibility and the magnetic susceptibility. Our
calculation is performed using both microscopic and phenomenological approaches
of the neutron matter equation of state, namely the Brueckner--Hartree--Fock
(BHF) approach using the Argonne V18 nucleon-nucleon potential supplemented
with the Urbana IX three-nucleon force, the effective Skyrme model in a
Hartree--Fock description, and the Quantum Hadrodynamic formulation with a mean
field approximation. All these approaches predict a change from completely spin
polarized to partially polarized matter that leads to a continuous equation of
state. The compressibility and the magnetic susceptibility show characteristic
behaviors, which reflect that fact. Thermal effects tend to smear out the
sharpness found for these quantities at T=0. In most cases a thermal increase
of 10 MeV is enough to hide the signals of the change of polarization. The set
of densities and magnetic field intensities for which the system changes it
spin polarization is different for each model. However, there is an overall
agreement between the three theoretical descriptions.Comment: updated to correspond with the published versio
Type-II super-Backlund transformation and integrable defects for the N=1 super sinh-Gordon model
A new super-Backlund transformation for the N=1 supersymmetric sinh-Gordon
equation is constructed. Based on this construction we propose a type-II
integrable defect for the supersymmetric sinh-Gordon model consistent with this
new transformation through the Lagrangian formalism. Explicit expressions for
the modified conserved energy, momentum and supercharges are also computed. In
addition, we show for the model that the type-II defect can also been regarded
as a pair of fused defects of a previously introduced type. The explicit
derivation of the associated defect matrices is also presented as a necessary
condition for the integrability of the model.Comment: Latex 31 pages. Version accepted for publicatio
Scharoun, conferencia con ocasión de la exposición “Berlin plant - Erster Bericht” [Berlín planifica - Primer Informe], leída el 5 de Septiembre de 1946
N=1 super sinh-Gordon model with defects revisited
The Lax pair formalism is considered to discuss the integrability of the N=1
supersymmetric sinh-Gordon model with a defect. We derive associated defect
matrix for the model and construct the generating functions of the modified
conserved quantities. The corresponding defect contributions for the modified
energy and momentum of the model are explicitly computed.Comment: Latex 26 page
An Information-Processing Perspective of IS-Business Integration: A Review of Research and a Conceptual Model
This paper presents a review framework of research related to inter-departmental integration, with a focus toward research into the IS-business relationship. While much of the literature reviewed lies outside the Information Systems realm, it is proposed here that related research in other business disciplines has much to contribute to the current interest in the integration between the Information Systems function, and line management in organizations. The main contribution of this manuscript lies in the identification of an appropriate theoretical base that can be employed in the study of this relationship
The Impact of the Reform of the Coast Act on the Body of Laws Governing the Catalan Coastline, with Special Reference to the Reduction of Protected Areas and the Invasions of the Powers of the Catalan Regional Government
La aprobación de la Ley 2/2013, de 29 de mayo, de Protección y Uso Sostenible del Litoral y de modificación de la Ley 22/1988, de 28 de julio, de Costas supone la mayor reforma del texto de la ley de costas desde su promulgación en 1988. La polémica, que ha acompañado a su redacción, ha abierto numerosas dudas jurídicas sobre cuáles son las consecuencias reales de la reforma para el litoral catalán, tanto desde la perspectiva de reducción del espacio protegido, como desde la perspectiva de nuevas invasiones competenciales en relación a las competencias de la Generalitat de Catalunya y los ayuntamientos. Este artículo aborda las dudas intentando aportar respuestas a las cuestiones planteadas y defendiendo la necesidad de redactar una ley propia de ordenación del litoral catalán que sirva para limitar los efectos negativos que la reforma supone.L’aprovació de la Llei 2/2013, de 29 de maig, de protecció i ús sostenible del litoral i de modificació de la Llei 22/1988, de 28 de juliol, de costes, suposa la major reforma del text de la Llei de costes des de la seva promulgació el 1988. La polèmica, que ha acompanyat la seva redacció, ha obert nombrosos dubtes jurídics sobre quines són les conseqüències reals de la reforma per al litoral català, tant des de la perspectiva de reducció de l’espai protegit com des de la perspectiva de noves invasions competencials en relació amb les competències de la Generalitat de Catalunya i els ajuntaments. Aquest article n’aborda els dubtes, tot intentant aportar respostes a les qüestions plantejades i defensant la necessitat de redactar una llei pròpia d’ordenació del litoral català que serveixi per limitar els efectes negatius que la reforma suposa.The passage of Act 2/2013, May 29, 2013, for the Protection and Sustainable Use of the Coastline, and the Modification of Coast Act 22/1988, July 28, 1988, represents the single greatest reform to the text of the Coast Act since it was enacted in 1988. The controvery surrounding the drafting of the Act has raised numerous legal doubts about just what the real consequences of the reform are for the Catalan coastline, both from the perspective of the reduction of protected areas and from the perspective of a new invasion of the powers that had previously been reserved to the Autonomous Government (Generalitat) and city councils of Catalonia. This article addresses these doubts, attempting to offer answers to the questions raised and defending the need to draft a local coastal planning law for Catalonia that could serve to limit the negative effects of the reform
Defects in the supersymmetric mKdV hierarchy via Backlund transformations
The integrability of the supersymmetric modified Korteweg
de-Vries (smKdV) hierarchy in the presence of defects is investigated through
the construction of its super B\"acklund transformation. The construction of
such transformation is performed by using essentially two methods: the
B\"acklund-defect matrix approach and the superfield approach. Firstly, we
employ the defect matrix associated to the hierarchy which turns out to be the
same for the supersymmetric sinh-Gordon (sshG) model. The method is general for
all flows and as an example we derive explicitly the B\"acklund equations in
components for the first few flows of the hierarchy, namely and .
Secondly, the supersymmetric extension of the B\"acklund transformation in the
superspace formalism is constructed for those flows. Finally, this super
B\"acklund transformation is employed to introduce type I defects for the
supersymmetric mKdV hierarchy. Further integrability aspects by considering
modified conserved quantities are derived from the defect matrix.Comment: 40 pages. Some comments and references added. Version accepted for
publication in JHE
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