61,277 research outputs found
Kondo Lattice Model with Finite Temperature Lanczos Method
We investigate the Kondo Lattice Model on 2D clusters using the Finite
Temperature Lanczos Method. The temperature dependence of thermodynamic and
correlations functions are systematically studied for various Kondo couplings
JK. The ground state value of the total local moment is presented as well.
Finally, the phase diagrams of the finite clusters are constructed for periodic
and open boundary conditions. For the two boundary conditions, two different
regimes are found for small JK/t, depending on the distribution of
non-interacting conduction electron states. If there are states within JK
around the Fermi level, two energy scales, linear and quadratic in JK, exist.
The former is associated with the onsite screening and the latter with the RKKY
interaction. If there are no states within JK around the Fermi level, the only
energy scale is that of the RKKY interaction. Our results imply that the form
of the electron density of states (DOS) plays an important role in the
competition between the Kondo screening and the RKKY interaction. The former is
stronger if the DOS is larger around the Fermi level, while the latter is less
sensitive to the form of the DOS.Comment: 7 pages, 7 figures; corrected typo
The Uncontrolled Social Utility Hypothesis Revisited
The experiment disentangles communication and social effect in face−to−face communication. The results question the previous interpretation of communication effects in ultimatum bargaining, and suggest that separate processes, both of a strategic and of an affective−social nature induce cooperative outcomes.
Diffraction in QCD
This lecture presents a short review of the main features of diffractive
processes and QCD inspired models. It includes the following topics: (1)
Quantum mechanics of diffraction: general properties; (2) Color dipole
description of diffraction; (3) Color transparency; (4) Soft diffraction in
hard reactions: DIS, Drell-Yan, Higgs production; (5) Why Pomerons interact
weakly; (6) Small gluonic spots in the proton; (7) Diffraction near the
unitarity bound: the Goulianos-Schlein "puzzle"; (8) Diffraction on nuclei:
diffractive Color Glass; (9) CGC and gluon shadowing.Comment: Based on the lecture given by B.K. at I LAWHEP, Porto Alegre, Brazil,
December 1-3, 200
Leading Neutrons From Polarized Proton-Nucleus Collisions
Leading neutron production on protons is known to be subject to strong
absorptive corrections, which have been under debate for a long time. On
nuclear targets these corrections are significantly enhanced and push the
partial cross sections of neutron production to the very periphery of the
nucleus. As a result, the A-dependences of inclusive and diffractive neutron
production turn out to be similar. The mechanism of \pi-a_1 interference, which
successfully explained the observed single-spin asymmetry of neutrons in
polarized pp interactions, is extended here to polarized pA collisions.
Corrected for nuclear effects it explains well the magnitude and sign of the
asymmetry A_N observed in inelastic events, resulting in a violent break up of
the nucleus. However the excessive magnitude of A_N observed in the diffractive
sample, remains a challenge.Comment: 5 pages, 4 figures. Invited talk at DIFFRACTION 2016, September 2 -
8, 2016, Sicil
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