Specific heat behavior of high temperature superconductors in the pseudogap regime

Experimental data obtained from thermodynamic measurements in underdoped high temperature superconductors show unusual anomalies in the temperature dependence of the electronic specific heat both in the normal state and at the critical point associated to the superconducting phase transition. The observed deviations from the standard behavior are probably linked with the opening of a pseudogap in the energy spectrum of the single-particle excitations associated with the normal state. Based on a phenomenological description of the pseudogap phase we perform analytical and numerical calculations for the temperature dependence of the specific heat for both the superconducting and normal state. The reduced specific heat jump at the transition point can be explained by a modified electronic single particle contribution to the specific heat in the presence of the normal state pseudogap. The hump observed in the normal state specific heat can be explained by the electronic pair contribution associated with strong fluctuations of the order parameter in the critical region. The obtained theoretical results are discussed in connection with experimental data for cuprates.Comment: 7 pages, 3 EPS figures. to appear in EPJ

A FUNCTIONAL SKETCH FOR RESOURCES MANAGEMENT IN COLLABORATIVE SYSTEMS FOR BUSINESS

This paper presents a functional design sketch for the resource management module of a highly scalable collaborative system. Small and medium enterprises require such tools in order to benefit from and develop innovative business ideas and technologies. As computing power is a modern increasing demand and no easy and cheap solutions are defined, especially small companies or emerging business projects abide a more accessible alternative. Our work targets to settle a model for how P2P architecture can be used as infrastructure for a collaborative system that delivers resource access services. We are focused on finding a workable collaborative strategy between peers so that the system offers a cheap, trustable and quality service. Thus, in this phase we are not concerned about solutions for a specific type of task to be executed by peers, but only considering CPU power as resource. This work concerns the resource management module as a part of a larger project in which we aim to build a collaborative system for businesses with important resource demandsresource management, p2p, open-systems, service oriented computing, collaborative systems