نتایج جستجو برای: fermi

تعداد نتایج: 21809  

1997
Ludovico Lanz Bassano Vacchini

Coherent and incoherent neutron-matter interaction is studied inside a recently introduced approach to subdynamics of a macrosystem. The equation describing the interaction is of the Lindblad type and using the Fermi pseudopotential we show that the commutator term is an optical potential leading to well-known relations in neutron optics. The other terms, usually ignored in optical descriptions...

2003
R. M. NIEMINEN

We have calculated electron and positron states in the Nd2_/ZexCuOq compound, for the perfect bulk lattice as well as when vacancy defects are included. We study the sensitivity of the results to different approximations in the positron potential. We also compute the annihilation rate and the electron-positron momentum density using the local density approximation and the newly developed gradie...

2016
H.H.J.E. Kicken

In recent magneto optical experiments (TR-MOKE) the timescale of laser induced demagnetization was found to be shorter than 0.5 ps. However, doubts have been raised if the measured signal reflects genuine loss of magnetic moment at all. Also, for these experiments no broadly accepted theory exists. Although a few models are able to fit the data, they generally have in common that they violate o...

2001
Maria C. Ruivo Pedro Costa Célia A. de Sousa

The behavior of kaons and pions in hot non strange quark matter, simulating neutron matter, is investigated within the SU(3) Nambu-Jona-Lasinio [NJL] and in the Enlarged Nambu-Jona-Lasinio [ENJL] (including vector pseudo-vector interaction) models. At zero temperature, it is found that in the NJL model, where the phase transition is first order, low energy modes with K, π+ quantum numbers, whic...

2017
J. W. Jeon W. J. Mullin

2014 A kinetic equation, which includes the effects of degeneracy, is derived for dilute, polarized systems by the Green’s function method of Kadanoff and Baym. When the Born approximation is used for the self-energy, the equation reduces to a result due to Silin. In the Boltzmann limit our result is equivalent to the equation of Lhuillier and Laloë, with the addition of a mean-field drift term...

1993
A. Dell'Acqua M. Hansen Sami J. Inkinen B. Lofstedt J. P. Vanuxem Christer Svensson Jiren Yuan H. Hentzell L. Del Buono J. David J. F. Genat H. Lebbolo O. LeDortz P. Nayman Aurore Savoy-Navarro R. Zitoun Cesare Alippi Luca Breveglieri Luigi Dadda Vincenzo Piuri Fabio Salice Mariagiovanna Sami Renato Stefanelli P. Cattaneo G. Fumagalli G. Goggi S. Brigati Umberto Gatti Franco Maloberti Guido Torelli P. Carlson A. Kerek Goran Appelquist S. Berglund C. Bohm Magnus Engström N. Yamdagni Rolf Sundblad I. Höglund S. T. Persson

The FERMl system, performing acquisition and DSP of calorimeter data in high energy collision experiments, planned at the LHC collider (CEW, Geneva, CH) is briefly overviewed. The system relies mainly upon the FERMI module, a dedicated VLSI multi-chip device per orming immediate neighbourhood of the collider itserJ; requiring rad-hard features. The issues for a system which absolutely requires ...

2006
Krishna Rajagopal Rishi Sharma

We analyze and compare candidate crystal structures for the crystalline color superconducting phase that may arise in cold, dense but not asymptotically dense, three-flavor quark matter. We determine the gap parameter ∆ and free energy Ω(∆) for many possible crystal structures within a Ginzburg-Landau approximation, evaluating Ω(∆) to order ∆. In contrast to the two-flavor case, we find a posit...

2008
J. B. Staunton J. Poulter B. Ginatempo E. Bruno D. D. Johnson

A scheme for making ab-initio calculations of the dynamic paramagnetic spin susceptibilities of solids at finite temperatures is described. It is based on TimeDependent Density Functional Theory and employs an electronic multiple scattering formalism. Incommensurate and commensurate anti-ferromagnetic spin fluctuations in paramagnetic Cr and compositionally disordered Cr95V5 and Cr95Re5 alloys ...

1998
Thomas Schäfer

Over the past years, important progress has been achieved in our understanding of the phase structure of QCD at finite temperature. Even though many important points remain to be worked out (like the nature of the QCD phase transition for realistic values of the quark masses), there is a nice frame work based on universality arguments and our ability to perform simulations on the lattice. For r...

Journal: :Caderno Brasileiro de Ensino de Física 2014

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