Search results for "paul"
showing 10 items of 281 documents
Effects of Pauli blocking on pion production in central collisions of neutron-rich nuclei
2020
Pauli blocking is carefully investigated for the processes of $NN \rightarrow N \Delta$ and $\Delta \rightarrow N \pi$ in heavy-ion collisions, aiming at a more precise prediction of the $\pi^-/ \pi^+$ ratio which is an important observable to constrain the high-density symmetry energy. We use the AMD+JAM approach, which combines the antisymmetrized molecular dynamics for the time evolution of nucleons and the JAM model to treat processes for $\Delta$ resonances and pions. As is known in general transport-code simulations, it is difficult to treat Pauli blocking very precisely due to unphysical fluctuations and additional smearing of the phase-space distribution function, when Pauli blockin…
Dephasing of orbital and spin degrees of freedom in semiconductor quantum dots due to phonons and magnons
2006
Phonon-induced decoherence of orbital degrees of freedom in quantum dots (QDs) (GaAs/InAs) is studied and the relevant time-scales are estimated versus dot dimension. Dephasing of excitons due to acoustic phonons and optical phonons, including enhancement of the effective Frohlich constant caused by localization, is assessed for the state-of-art QDs. Temporal inefficiency of Pauli blocking in QDs due to lattice inertia is additionally predicted. For QD placed in a diluted magnetic semiconductor medium a magnon induced dephasing of spin is estimated in accordance with experimental results for Zn(Mn)Se/CdSe. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Unavoidable decoherence in semiconductor quantum dots
2005
Phonon-induced unavoidable decoherence of orbital degrees of freedom in quantum dots is studied and the relevant time scales are estimated. Dephasing of excitons due to acoustic phonons and, in a polar medium, to optical phonons, including anharmonic effects and enhancement of the effective Fr\"ohlich constant due to localization, is assessed for typical self-assembled quantum dots. Temporal inefficiency of Pauli blocking due to lattice inertia is predicted. For quantum dots placed in a diluted magnetic semiconductor medium a magnon-induced dephasing of a spin is also estimated in accordance with experimental results.
Testing electromagnetic proton form factors in the annihilation process p+p¯→π0+e−+e+
2011
We study the annihilation channel in proton antiproton collisions with production of a single neutral pion and an electron-positron pair. It is shown that this reaction allows access to the proton electromagnetic form factors in the ‘unphysical’ region and to the difference between complex phases of the Dirac and Pauli proton form factors. The differential cross section is given in the laboratory frame in an experimental setup where all outgoing particles are fully detected.
Composite Operator Method analysis of the underdoped cuprates puzzle
2014
The microscopical analysis of the unconventional and puzzling physics of the underdoped cuprates, as carried out lately by means of the Composite Operator Method (COM) applied to the 2D Hubbard model, is reviewed and systematized. The 2D Hubbard model has been adopted as it has been considered the minimal model capable to describe the most peculiar features of cuprates held responsible for their anomalous behavior. COM is designed to endorse, since its foundations, the systematic emergence in any SCS of new elementary excitations described by composite operators obeying non-canonical algebras. In this case (underdoped cuprates - 2D Hubbard model), the residual interactions - beyond a 2-pole…
Shell structure in mixed3He−4Hedroplets
2004
Due to the immiscibility of ${}^{3}\mathrm{He}$ into ${}^{4}\mathrm{He}$ at very low temperatures, mixed helium droplets consist of a core of ${}^{4}\mathrm{He}$ atoms coated by a ${}^{3}\mathrm{He}$ layer whose thickness depends on the number of atoms of each isotope. When these numbers are such that the centrifugal kinetic energy of the ${}^{3}\mathrm{He}$ atoms is small and can be considered as a perturbation to the mean-field energy, a novel shell structure arises, with magic numbers different from these of pure ${}^{3}\mathrm{He}$ droplets. If the outermost shell is not completely filled, the valence atoms align their spins up to the maximum value allowed by the Pauli principle.
The Pauli Principle and Systems Consisting of Composite Particles
1993
In nature we often deal with many-body systems that are described in terms of particles that are not elementary but themselves composite. Examples of such composite particles are hadrons, atoms, phonons, and Cooper pairs. For the description of systems consisting of such composite particles in terms of the underlying degrees of freedom group theory plays an important role, in particular the symmetric group to describe the permutational symmetry of the wave function of the system, and unitary groups to describe the symmetry forced on the system by the interaction between the particles.
Phytophthora Root and Collar Rot of Paulownia, a New Disease for Europe
2021
Paulownia species are fast growing trees native to China, which are being grown in managed plantings in several European countries for the production of wood and biomasses. In 2018, wilting, stunting, leaf yellowing, and collapse, as a consequence of root and crown rot, were observed in around 40% of trees of a 2-year-old planting of Paulownia elongata × P. fortunei in Calabria (Southern Italy). Two species of Phytophthora were consistently recovered from roots, basal stem bark, and rhizosphere soil of symptomatic trees and were identified as Ph. nicotianae and Ph. palmivora on the basis of both morphological characteristics and phylogenetic analysis of rDNA ITS sequences. Koch’s postulates…
Cinema as locus theologicus: Popes in film (from Leo XIII till Benedict XVI)
2020
Bishops of Rome have been, since the dawn of the cinema, a subject interesting for filmmakers and important for the Church, as a source of information on the papacy. Numerous feature and documentary films presented biographies, activities or teaching of the Popes. But in the context of theology, we should not forget that a film – be it biographical, historical or telling merely a fictional story – can be regarded as a locus theologicus. However, fictionalised biographies of the Popes are not strictly historical films, neither are these films hagiographies, because the view of the Pope is taken from an external perspective, distant from the faith. Rather, it is a particular genre, which chal…