SU(N) Antiferromagnets and Strongly Coupled QED: Effective Field Theory for Josephson Junctions Arrays

We review our analysis of the strong coupling of compact QED on a lattice with staggered Fermions. We show that, for infinite coupling, compact QED is exactly mapped in a quantum antiferromagnet. We discuss some aspects of this correspondence relevant for effective field theories of Josephson junctions arrays.Comment: 33 pages,latex,Proceedings of "Common Trends in Condensed Matter and High Energy Physics",DFUPG 1/9

SU(N) Quantum Antiferromagnets and the Phase Structure of QED in the Strong Coupling Limit

We examine the strong coupling limit of both compact and non compact QED on a lattice with staggered fermions. We show that every SU(N) antiferromagnet with spins in a particular fundamental representation of the SU(N) Lie Algebra and with nearest neighbor couplings on a bipartite lattice is exactly equivalent to the infinite coupling limit of lattice QED with the numbers of flavors of electrons related to N and the dimension of spacetime D+1. We find that,for both compact and noncompact QED,when N is odd the ground state of the strong coupling limit breaks chiral symmetry in any dimensions and for any N and the condensate is an isoscalar mass operator. When N is even,chiral symmetry is broken if D is bigger or equal to 2 and N is small enough and the order parameter is an isovector mass operator. We also find the exact ground state of the lattice Coulomb gas as well as a variety of related lattice statistical systems with long ranged interactions.Comment: latex, 45 pages, DFUPG 69/9

The Dutch sociology of education: Its origins, significance and future

Contains fulltext : 28833.pdf (publisher's version ) (Open Access)As in many other countries the Dutch sociology of education has blossomed into a fully-fledged specialised branch of sociology since the beginning of the 1970s. A tradition of policy-oriented research has also consolidated the position of the sociology of education at the universities. The strength of this relatively small group of specialists lies in the solid empirical basis and use of advanced research techniques and analyses in their work. Theory and reflection are not the strongest qualities of this group. A good organisational structure naturally helps keep the ranks closed. Recently, however, marginalisation of the specialism is threatening because of isolation from general sociology. Mainstream educationalists and policy-makers are also challenging the sociologists of education to make their contribution more explicit than ever