Organisational Challenges Facing Civil Society Networks in Malawi

The research results provide a snapshot of civil society networks in Malawi today, whilst highlighting the critical organisational challenges in 2006. The project did not aim for nor did it achieve an exhaustive impact assessment of all civil society networks in the country. Interviews focussed on three networks: Malawi Economic Justice Network (MEJN), Land Task Force (LTF) and Civil Society Coalition on Basic Quality Education (CSCQBE). The findings therefore directly relate to thesethree networks; although they have resonance with other civil society networks in Malawi and globally.The main elements of the research methodology included: Literature review to provide an overview of current thinking (see references);Semi-structured interviews with up to 25 stakeholders for Malawi Economic Justice Network (MEJN), Civil Society Coalition for Quality Basic Education (CSCQBE), Land Task Force (LTF), other CSO networks, donors, and government;Analysis of consultancy work with MEJN and Civil Society Agriculture Network (CISANET);Analysis and write up;Publication and dissemination.The paper will briefly discuss the development impact of the CSOs before proceeding to discuss the critical organisational capacity issues facing the networks

Optimized Perturbation Theory at Finite Temperature--- Two-Loop Analysis---

We study the optimized perturbation theory (OPT) at finite temperature, which is a self-consistent resummation method. Firstly, we generalize the idea of the OPT to optimize the coupling constant in lambda phi^4 theory, and give a proof of the renormalizability of this generalized OPT. Secondly, the principle of minimal sensitivity and the criterion of the fastest apparent convergence, which are conditions to determine the optimal parameter values, are examined in lambda phi^4 theory. Both conditions exhibit a second-order transition at finite temperature with critical exponent beta = 0.5 in the two-loop approximation.Comment: PTPTeX 22 pages, with 18 eps figure

Linear Sigma model in the Gaussian wave functional approximation II: Analyticity of the S-matrix and the effective potential/action

We show an explicit connection between the solution to the equations of motion in the Gaussian functional approximation and the minimum of the (Gaussian) effective potential/action of the linear $\Sigma$ model, as well as with the N/D method in dispersion theory. The resulting equations contain analytic functions with branch cuts in the complex mass squared plane. Therefore the minimum of the effective action may lie in the complex mass squared plane. Many solutions to these equations can be found on the second, third, etc. Riemann sheets of the equation, though their physical interpretation is not clear. Our results and the established properties of the S-matrix in general, and of the N/D solutions in particular, guide us to the correct choice of the Riemann sheet. We count the number of states and find only one in each spin-parity and isospin channel with quantum numbers corresponding to the fields in the Lagrangian, i.e. to Castillejo-Dalitz-Dyson (CDD) poles. We examine the numerical solutions in both the strong and weak coupling regimes and calculate the Kallen-Lehmann spectral densities and then use them for physical interpretation.Comment: 14 pages, 4 ps figures, to appear in Nucl. Phy

Thermodynamics of O(N) sigma models: 1/N corrections

The thermodynamics of the O(N) linear and nonlinear sigma models in 3+1 dimensions is studied. We calculate the pressure to next-to-leading order in the 1/N expansion and show that at this order, temperature-independent renormalization is only possible at the minimum of the effective potential. The 1/N expansion is found to be a good expansion for N as low as 4, which is the case relevant for low-energy QCD phenomenology. We consider the cases with and without explicit symmetry breaking. We show that previous next-to-leading order calculations of the pressure are either breaking down in the temperatures of interest, or based on unjustifiable high-energy approximations.Comment: 11 pages, 5 figures, revte

Optimized perturbation theory at finite temperature

The naive perturbation theory is known to break down at high temperature (T). This is because higher order terms are enhanced by the powers of T and eventually exceed the lower order terms even if the expansion parameter in the perturbation is small. These large terms at high T are called the hard thermal loops (HTLs).Therefore, we need to resum HTLs to obtain sensible results at high T. So far, several methods have been proposed to carry out this resummation. Asone of the promising candidates, self-consistent resummation method has been studied for a long time. However, it was found that the method has difficulties in therenormalization at finite T and in the proof of the Nambu-Goldstone theorem at finite T. In this thesis, we develop an optimized perturbation theory (OPT) at finite temperature in the O(N) Φ4 theory, which can resum higher order terms at finite T without the problems mentioned above. It has the following features: 1. Hard thermal loops are correctly resummed at high T. 2. The renormalization of the ultra-violet divergences can be carried out systematically in any given order of OPT. 3. The Nambu-Goldstone theorem is fulfilled for arbitrary N and the any givenorder of OPT.Thesis (Ph. D. in Physics)--University of Tsukuba, (A), no. 2306, 2000.3.24Bibliography: p. 85-9

Low-momentum Pion Enhancement Induced by Chiral Symmetry Restoration

The thermal and nonthermal pion production by sigma decay and its relation with chiral symmetry restoration in a hot and dense matter are investigated. The nonthermal decay into pions of sigma mesons which are popularly produced in chiral symmetric phase leads to a low-momentum pion enhancement as a possible signature of chiral phase transition at finite temperature and density.Comment: 3 pages, 2 figure

The boundary of the first order chiral phase transition in the m_pi-m_K--plane with a linear sigma model

Tree-level and complete one-loop parametrisation of the linear sigma model (LSM) is performed and the phase boundary between first order and crossover transition regions of the m_pi-m_K-plane is determined using the optimised perturbation theory (OPT) as a resummation tool of perturbative series. Away from the physical point the parameters of the model were determined by making use of chiral perturbation theory (ChPT). The location of the phase boundary for m_pi=m_K and of the tricritical point (TCP) on the m_pi=0 were estimated.Comment: 4 pages, 1 figure, uses espcrc1.sty; to appear in the proceedings of Strong and Electroweak Matter 2006 (SEWM06), BNL, May 200

The Fokker-Planck equation for bistable potential in the optimized expansion

The optimized expansion is used to formulate a systematic approximation scheme to the probability distribution of a stochastic system. The first order approximation for the one-dimensional system driven by noise in an anharmonic potential is shown to agree well with the exact solution of the Fokker-Planck equation. Even for a bistable system the whole period of evolution to equilibrium is correctly described at various noise intensities.Comment: 12 pages, LATEX, 3 Postscript figures compressed an

Mean field theory for collective motion of quantum meson fields

Mean field theory for the time evolution of quantum meson fields is studied in terms of the functional Schroedinger picture with a time-dependent Gaussian variational wave functional. We first show that the equations of motion for the variational wavefunctional can be rewritten in a compact form similar to the Hartree-Bogoliubov equations in quantum many-body theory and this result is used to recover the covariance of the theory. We then apply this method to the O(N) model and present analytic solutions of the mean field evolution equations for an N-component scalar field. These solutions correspond to quantum rotations in isospin space and represent generalizations of the classical solutions obtained earlier by Anselm and Ryskin. As compared to classical solutions new effects arise because of the coupling between the average value of the field and its quantum fluctuations. We show how to generalize these solutions to the case of mean field dynamics at finite temperature. The relevance of these solutions for the observation of a coherent collective state or a disoriented chiral condensate in ultra-relativistic nuclear collisions is discussed.Comment: 31 pages, 2 Postscript figures, uses ptptex.st