6,960 research outputs found
Charge Gap in the One-Dimensional Extended Hubbard Model at Quarter Filling
We propose a new combined approach of the exact diagonalization, the
renormalization group and the Bethe ansatz for precise estimates of the charge
gap in the one-dimensional extended Hubbard model with the onsite and
the nearest-neighbor interactions and at quarter filling. This approach
enables us to obtain the absolute value of including the prefactor
without ambiguity even in the critical regime of the metal-insulator transition
(MIT) where is exponentially small, beyond usual renormalization group
methods and/or finite size scaling approaches. The detailed results of
down to of order of near the MIT are shown as contour lines on the
- plane.Comment: 4 pages, 4 figure
Dimerization in a half-filled one-dimensional extended Hubbard model
We use a density matrix renormalization group method to study quantitatively
the phase diagram of a one-dimensional extended Hubbard model at half-filling
by investigating the correlation functions and structure factors. We confirm
the existence of a novel narrow region with long-rang bond-order-wave order
which is highly controversial recently between the charge-density-wave phase
and Mott insulator phase. We determined accurately the position of the
tricritical point , which is quite different
from previous studies
Les réformes de l'administration publique en Suisse
Cet article fait le point sur les réformes de la gestion publique en Suisse. Après avoir montré que ce pays est marqué par une tradition de modernisation qui le rend très réceptif aux nouvelles approches de gestion, l'article analyse en particulier le mouvement de Nouvelle Gestion Publique (NGP) à la mode helvétique. Les principales orientations de la NGP suisse, ainsi que les évaluations qui en ont été faites sous l'angle des autorités politiques, de l'administration et des citoyens, permettent d'esquisser les défis qui attendent le système suisse dans l'ère de l'après-NGP
Rewarding civil service performance through team bonuses : findings, analysis and recommendations
Performance-related pay within public organizations is continuing to spread. Although it can help to strengthen an entrepreneurial spirit in civil servants, its implementation is marred by technical, financial, managerial and cultural problems. This article identifies an added problem, namely the contradiction that exists between a managerial discourse that emphasizes the team and collective performance, on the one hand, and the use of appraisal and reward tools that are above all individual, on the other. Based on an empirical survey carried out within Swiss public organizations, the analysis shows that the team is currently rarely taken into account and singles out the principal routes towards an integrated system for the management and rewarding of civil servants
La gestion par les résultats dans les organisations publiques : de l'idée aux défis de la réalisation
Gestion prévisionnelle du personnel au XXIème siècle : les défis d'un processus-clés de la GRH
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