Statistical mechanics on the square lattice

We investigate the statistical mechanical properties of spin models on the square lattice, using the technique of transfer matrices. With the aid of exact diagonalisation we obtain results which indicate that excitations of the transfer matrix can be thought of as physical objects which we term topological excitations, which are domain walls in the case of the Ising model at low temperature. Inspired by these results, we extend the usefulness of Baker-Campbell-Hausdorff formula by finding and proving a new representation. This mathematical result is the major contribution of this thesis to the wider literature. Applying perturbation theory to it allows us to perturbatively find the eigenvalues of a square lattice transfer matrix in a way reminiscent of a high-temperature expansion. We then do so for the Ising model, comparing our results to known formulae, and extend the calculation to Potts models

Family Matters: (e)migration, familial networks and Irish women in Britain

The recent increase in transnational migration among women has lead to a reappraisal of theoretical explanations of migratory movement (Castles and Miller, 2003; Fortier, 2000; Zulauf, 2001). This paper reviews a number of theoretical explanations of transnational migration and then applies these theories to a qualitative study of women who migrated from Ireland to Britain in the 1930s. I explore the women's reasons for leaving Ireland and their experiences as young economic migrants in Britain in the inter-war years. Women have made up the majority of Irish migrants to Britain for much of the twentieth century yet the dominant stereotype of the Irish migrant has been the Mick or Paddy image (Walter, 2001). Through an analysis of these twelve women's narratives of migration, I explore themes such as household strategies and familial networks. I am interested in the interwoven explanations of migration as both a form of escape (O'Carroll, 1990) and a rational family strategy and, hence, the ways in which women's decision to migrate can be seen as a combination of both active agency and family obligation. Drawing on the work of Phizacklea (1999) as well as Walter (2001) and Gray (1996, 1997), I will analyse the ways in which family connections may transcend migration and engage with the concept of 'transnational family' (Chamberlain, 1995). In so doing, I raise questions about the complex nature of migration and the extent to which it could be described in terms of empowerment