5,062 research outputs found
Quantum phase transitions in odd-A nuclei: The effect of the odd particle from spherical to oblate shapes
Quantum shape-phase transitions in odd-nuclei are investigated within the framework of the interacting boson-fermion model (IBFM). We consider the case of a single-j fermion coupled to an even-even boson core that performs a transition from spherical to oblate shapes varying a control parameter in the boson Hamiltonian. The aim of this work is to see the effect of the coupling of the unpaired fermion on the transition, to understand how the coupled single particle modifies the geometric shape of the system and how each of the odd states behaves when the boson core shifts along the transitional path.Scientific and Technical Research Council of Turkey BIDEB-2224AMinisterio de Economía y Competitividad FIS2011-28738- c02-01, CSD2007-00042Junta de Andalucía FQM160, P11-FQM-763
Hermitian and G2-structures with large symmetry groups
In the context of Hermitian geometry, the Hull--Strominger system is a system of non-linear PDEs on heterotic string theory, over a six-dimensional manifold endowed with an SU(3)-structure. Its seven-dimensional analogue, the heterotic G2 system, is a system for both geometric fields and gauge fields over a manifold with a G2-structure. In this thesis, we study manifolds with geometric structures compatible with the Hull--Strominger system and the heterotic G2 system in the cohomogeneity one setting. In the former case, we develop a case-by-case analysis to provide a non-existence result for balanced non-Kähler SU(3)-structures which are invariant under a cohomogeneity one action on a simply connected six-manifold. In the latter case, we study two different SU(2)2-invariant cohomogeneity one manifolds, one non-compact M = R4 x S3, and one compact M = S4 x S3. For R4 x S3, we prove the existence of a family of coclosed (but not necessarily torsion-free) G2-structures which is given by three smooth functions satisfying certain boundary conditions around the singular orbit and a non-zero parameter. Moreover, any coclosed G2-structure constructed from a half-flat SU(3)-structure is in this family. For S4 x S3, we prove that there are no SU(2)2-invariant coclosed G2-structures constructed from half-flat SU(3)-structures. Then, we study the existence of SU(2)2-invariant G2-instantons on R4 x S3 manifold with the coclosed G2-structures found. We find two 1-parameter families of smooth SU(2)3-invariant G2-instantons with gauge group SU(2) on R4 x S3 and study its ``bubbling'' behaviour. We also provide existence results for locally defined SU(2)2-invariant G2-instantons
That Night Has a Color
There are no human words to express the pain and the sadness. To begin to understand the reasons why a life so young ends, one must do it through a divine glance. Whether that is love or God herself. I try to do it through music, with the hope to heal that emptiness that is left in the world. I hope that by swimming and submerging yourself fully in the pain, it helps loose the fear of it and therefore, in consequence, we can see the love and happiness again that we only but missed.https://remix.berklee.edu/graduate-studies-scoring/1154/thumbnail.jp
Caracterización económica-financiera de las empresas agroalimentarias. Un análisis comparado entre España y Portugal
El análisis de la información contable de las empresas es de vital importancia para diagnosticar la situación de un sector y para identificar problemas y definir estrategias. El objetivo de este trabajo es realizar una caracterización de las empresas agroalimentarias de España y Portugal en el periodo 1991-2006 a partir de los documentos contables que las empresas presentan voluntariamente a sus respectivos bancos centrales. La información se ha tomado de la base de datos BACH (Bank for the Accounts of Companies Harmonised) que contiene información contable armonizada de las empresas no financieras de 11 países europeos, Japón y Estados Unidos. Para estudiar las empresas agroalimentarias, se ha tomado información de las empresas incluidas en la clase DA, manufacturas de alimentos, bebidas y tabacos
Review of critical point symmetries and shape phasetransitions within algebraic and collective models
Several aspect of shape phase transitions and critical point symmstries are reviewed inthis contribution within the frameworks of the Interacting Boson Model(IBM) and theInteracting Boson Fermion Model(IBFM) for even and odd sysstems respectively andcompared with collective geometric models. We discuss in particular the case of an oddj= 3/2 particle coupled to an even-even boson core that undergoes a transition from thespherical limitU(5) to theγ-unstable limitO(6). The spectrum and transition rates atthe critical point are similar to those of the even core and they agree qualitatively with theE(5/4) boson-fermion symmetry. We discuss also theUBF(5) toSUBF(3) shape phasetransition in which the allowed fermionic orbitals arej= 1/2,3/2,5/2. The formalismof the intrinsic or coherent states is used to describe in details the ground state as wellas the excitedβ−andγ−bands. This formalism is also used to calculate the PotentialEnergy Surface of the cubic quadrupole operator that leads to traixial
Importance of the single-particle continuum in BCS pairing with a pseudostate basis
In a recent work [arXiv:1510.03185] the use of the Transformed Harmonic Oscillator (THO) basis for the discretization of the singleparticle continuum into a Generalized Bardeen-Cooper-Schrieffer (BCS) formalism was proposed for the description of weakly bound nuclei. We make use of the flexibility of this formalism to study the evolution of the pairing when the nucleus becomes more and more weakly bound. Specifically we focus on the evolution of the occupation of the different partial waves in 22O when the Fermi level approaches zer
Basic symptoms and cognitive dynamic disorders in schizophrenic patients
Producción CientíficaUsing a new scientific paradigm, chaotic-deterministic
dynamics, our research group developed a new cognitive
instrument which is administered by means of a computen
the Test of Random Rhythm Generation (ARG). Theoretical
background and preliminary results in two young male,
defectual schizophrenic patients (paranoid type) are here
presented. Basic symptoms were explored by means of the
Frankfurt Complaint Questionnaire of FBF (Frankfurter
Beschwerde-Fragebogen) and the Bonn Scale for the Assessment
of Basic Symptoms of Gross et al. Possible relationships
between cerebral complexity and basic symptoms
are discussed. It is concluded that the ARG is a valuable
technique to measure the patient's cognitive potential as
well as his complexity level (or cerebral chaotic dynamic
complexity). Finally, it is hypothesized that defectual psychotic
patients genérate more rigid and rhythmic series
than control groups. Further work must be done in this new
research field
Cost of energy and mutual shadows in a two-axis tracking PV system
The performance improvement obtained from the use of trackers in a PV system cannot be separated from the higher requirement of land due to the mutual shadows between generators. Thus, the optimal choice of distances between trackers is a compromise between productivity and land use to minimize the cost of the energy produced by the PV system during its lifetime.
This paper develops a method for the estimation and optimization of the cost of energy function. It is built upon a set of equations to model the mutual shadows geometry and a procedure for the optimal choice of the wire cross-section. Several examples illustrate the use of the method with a particular PV system under different conditions of land and equipment costs.
This method is implemented using free software available as supplementary material
UBF(5) to SUBF(3) shape phase transition in odd nuclei for j=1/2, 3/2, and 5/2 orbits: The role of the odd particle at the critical point
We investigate the phase transition in odd nuclei within the Interacting Boson Fermion Model in correspondence with the transition from spherical to stable axially deformed shape. The odd particle is assumed to be moving in the single-particle orbitals with angular momenta j=1/2,3/2,5/2 with a boson-fermion Hamiltonian that leads to the occurrence of the SUBF(3) boson-fermion symmetry when the boson part approaches the SU(3) condition. Both energy spectra and electromagnetic transitions show characteristic patterns similar to those displayed by the even nuclei at the corresponding critical point. The role of the additional particle in characterizing the properties of the critical points in finite quantal systems is investigated by resorting to the formalism based on the intrinsic frame.Ministerio de Educación y Ciencia y FEDER FIS2008-04189Programa Consolider-Ingenio 2010 CSD2007-00042Junta de Andalucía FQM160 P07-FQM-0289
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