Destruction of Long-range Order by Quenching the Hopping Range in One Dimension

We study the dynamics in a one dimensional hard-core Bose gas with power-law hopping after an abrupt reduction of the hopping range using the time-dependent density-matrix renormalization group (t-DMRG) and bosonization techniques. In particular, we focus on the destruction of the Bose-Einstein condensate (BEC), which is present in the initial state in the thermodynamic limit. We argue that this type of quench is akin to a sudden reduction in the effective dimensionality $d$ of the system (from $d > 1$ to $d = 1$). We identify two regimes in the evolution of the BEC fraction. For short times the decay of the BEC fraction is Gaussian while for intermediate to long times, it is well described by a stretched exponential with an exponent that depends on the initial effective dimensionality of the system. These results are potentially relevant for cold trapped-ion experiments which can simulate an equivalent of hard-core bosons, i.e. spins, with tunable long-range interactions.Comment: 8 pages, 7 figures, accepted for publication in Phys. Rev.

Multiple goals and ownership structure : effects on the performance of Spanish savings banks.

Spanish savings banks (SBs) are financial institutions with a wide mission that includes different stakeholders’ goals. Profit maximization is only one among several goals, and the widespread use of cost or profit efficiency as the only comparative performance measure may prove to be insufficient in this context. To overcome this problem, we build an aggregate performance index for organizations with multiple goals. Furthermore, we show how the ownership structure of SBs influences their economic behavior in two basic ways: (1) the performance level and (2) their goal priorities. In particular, we distinguish two types of ownership structures in our application, namely, organizations controlled by Public Administrations and those controlled by insiders (i.e. managers and workers). Our results indicate that each type has different priorities and differ in their performance indexes. More specifically, the empirical analysis shows that insider-controlled SBs favor goals related to profit maximization and the universal access to financial services and, furthermore, they perform better. In contrast, contributing to regional development becomes the most favored goal when Public Administrations have a majority in the bank.

Assessing Judicial Efficiency of Egyptian First Instance Courts: A DEA Analysis

Egypt started a recent judicial reform program in 2007, which can be considered the first ever since the establishment of the National Egyptian Judicial System in 1952. It focuses mainly on solving organizational problems within First Instance Courts (FIC), as they form the active cell of the Egyptian judicial system. However the efficiency of FICs is still doubtable to a large extent. This paper provides for the first time an efficiency analysis of 22 FICs in Egypt using the technique of Data Envelop Analysis (DEA). The main strength of this study is to consider the number of computers per court, as none of the previous papers on court efficiency has included a capital variable when defining their court production function before. Our results show that there are no significant differences observed in terms of management efficiency between the civil and criminal FICs, however criminal FICs districts are superior with respect to their corresponding civil districts in terms of program efficiency.Egyptian Judicial System; Efficiency; Data envelopment analysis