Correction to the geometric phase by structured environments: the onset of non-Markovian effects

We study the geometric phase of a two-level system under the presence of a structured environment, particularly analysing its correction with the ohmicity parameter $s$ and the onset of non-Markovianity. We firstly examine the system coupled to a set of harmonic oscillators and studied the decoherence factor as function of the environment's ohmicity parameter. Secondly, we propose the two-level system coupled to a non-equilibrium environment, and show that these environments display non-Markovian effects for all values of the ohmicity parameter. The geometric phase of the two-level system is therefore computed under the presence of both types of environment. The correction to the unitary geometric phase is analysed in both, Markovian and non-Markovian regimes. Under Markovian environments, the correction induced on the system's phase is mainly ruled by the coupling constant between the system and the environment, while in the non-Markovian regime, memory effects seem to trigger a significant correction to the unitary geometric phase. The result is significant to the quantum information processing based on the geometric phase in quantum open systemsComment: 7 figures. Accepted for publication in Phys. Rev. A. arXiv admin note: text overlap with arXiv:1303.493

Decoherence in composite quantum open systems: the effectiveness of unstable degrees of freedom

The effect induced by an environment on a composite quantum system is studied. The model considers the composite system as comprised by a subsystem A coupled to a subsystem B which is also coupled to an external environment. We study all possible four combinations of subsystems A and B made up with a harmonic oscillator and an upside down oscillator. We analyzed the decoherence suffered by subsystem A due to an effective environment composed by subsystem B and the external reservoir. In all the cases we found that subsystem A decoheres even though it interacts with the environment only through its sole coupling to B. However, the effectiveness of the diffusion depends on the unstable nature of subsystem A and B. Therefore, the role of this degree of freedom in the effective environment is analyzed in detailComment: 20 pages, 4 figures. Version to appear in Int. J. Mod. Phys.

Decoherence of a solid-state qubit by different noise correlation spectra

The interaction between solid-state qubits and their environmental degrees of freedom produces non-unitary effects like decoherence and dissipation. Uncontrolled decoherence is one of the main obstacles that must be overcome in quantum information processing. We study the dynamically decay of coherences in a solid-state qubit by means of the use of a master equation. We analyse the effects induced by thermal Ohmic environments and low-frequency 1/f noise. We focus on the effect of longitudinal and transversal noise on the superconducting qubit's dynamics. Our results can be used to design experimental future setups when manipulating superconducting qubits.Comment: 14 pages, 9 figures. Version to appear in Physics Letters A. arXiv admin note: text overlap with arXiv:0809.4716 by other author

"Inflation Targeting in Brazil"

The purpose of this paper is to examine inflation targeting (IT) in emerging countries by concentrating essentially on the case of Brazil. The IT monetary policy regime has been adopted by a significant number of countries. While the focus of this paper is on Brazil, which began inflation targeting in 1999, we also examine the experience of other countries, both for comparative purposes and for evidence of the extent of this "new" economic policy's success. In addition, we compare the experience of Brazil with that of non-IT countries, and ask the question of whether adopting IT makes a difference in the fight against inflation.

Banking Internationalisation and the Expansion Strategies of European Banks to Brazil during the 1990s

This paper aims at analysing the determinants of the recent wave of European banks to Brazil in the context of the recent phase of banking internationalisation. The first part analyses the process of banking internationalisation from both an analytical and an historical approach. Focusing on the determinants of the banking internationalisation process, the paper shows that (i) the recent wave of banking internationalisation is characterised not only for financial institutions pursuing their existing relationships, but also and increasingly by a greater integration into the local market; (ii) banks operating in countries where the banking sector is larger and more profitable should be able to export a superior skill and are more likely to expand their activities abroad. The second part of the paper examines the determinants of the expansion of European banks in Brazil, as well as the expansion strategy of the four major European banks in Latin America – BSCH, BBVA, HSBC and ABN-Amro. In this regard, it shows that the recent wave of European banks entering Latin America and Brazil is determined by several factors, that include the process of restructuring the banking sector under the EMU; the dynamics of the internationalisation of the Spanish banks, since they have been the main players in the recent influx of foreign banks into Latin America; the process of market deregulation in the region since the early 1990s, in the broader context of economic and political reforms; the better prospects of the region for increasing returns to financial institutions compared to developed countries, as well as the potential gains in efficiency. Besides, it also shows that one of the common features of the four major European banks in Latin America – BSCH, BBVA, HSBC and ABNAmro – is that all the top four are big universal banks that choose to expand abroad as a strategy to expand their activities. More precisely, expanding abroad is not only a source of diversification of earnings, but also a way to strengthen their position in the European banking market under the pressure of economic and monetary union.

Macroscopic tunneling, decoherence and noise-induced activation

We study the effects of the environment at zero temperature on tunneling in an open system described by a static double-well potential. We show that the evolution of the system in an initial Schrodinger cat state, can be summarized in terms of three main physical phenomena, namely decoherence, quantum tunneling and noise-induced activation. Using large-scale numerical simulations, we obtain a detailed picture of the main stages of the evolution and of the relevant dynamical processesComment: Contribution to the Proceedings of DICE'0

Intertwining Judicial Reforms and the Use of ICT in Courts: A Brief Description of the Portuguese Experience

This paper, focusing on the Portuguese experience, analyzes changes on the legal framework and the governance requirements in the different stages of development and implementation of courts’ ICT. To this end, the paper provides for a concise description of the Portuguese justice system and of the main challenges its organization and territorial division has faced in the last decades. Follows a description of the introduction of the two main courts’ information systems in: CITIUS (for judicial courts) and SITAF(for administrative and tax courts). The paper then on focuses the recent measures adopted under the Justiça + Próxima plan, analyzing the main needs they intend to address and goals they expect to fulfill, in the attempt to understand if they will be able to introduce the new era of courts e-services that has been promised