Phase transitions and anomalous normal state in superconductors with broken time reversal symmetry

Using Monte Carlo simulations, we explore the phase diagram and the phase transitions in \groupUZ $n$-band superconductors with spontaneously broken time-reversal symmetry (also termed $s+is$ superconductors), focusing on the three-band case. In the limit of infinite penetration length, the system under consideration can, for a certain parameter regime, have a single first order phase transition from a \groupUZ broken state to a normal state due to a nontrivial interplay between \groupU vortices and \groupZ domain walls. This regime may also apply to multicomponent superfluids. For other parameters, when the free energy of the domain walls is low, the system undergoes a restoration of broken \groupZ time reversal symmetry at temperatures lower than the temperature of the superconducting phase transition.{We show that inclusion of fluctuations can strongly suppress the temperature of the \groupZ-transition when frustration is weak. The main result of our paper is that} for relatively short magnetic field penetration lengths, the system has a superconducting phase transition at a temperature lower than the temperature of the restoration of the broken \groupZ symmetry. Thus, there appears a new phase which is \groupU-symmetric, but breaks \groupZ time reversal symmetry, an anomalous dissipative (metallic) state.Comment: 12 pages, 12 figures, submitted to Physical Review

Phase structure and phase transitions in a three dimensional SU(2) superconductor

We study the three dimensional SU(2)-symmetric noncompact CP1 model, with two charged matter fields coupled minimally to a noncompact Abelian gauge-field. The phase diagram and the nature of the phase transitions in this model have attracted much interest after it was proposed to describe an unusual continuous transition associated with deconfinement of spinons. Previously, it has been demonstrated for various two-component gauge theories that weakly first-order transitions may appear as continuous ones of a new universality class in simulations of relatively large, but finite systems. We have performed Monte-Carlo calculations on substantially larger systems sizes than those in previous works. We find that in some area of the phase diagram where at finite sizes one gets signatures consistent with a single first-order transition, in fact there is a sequence of two phase transitions with an O(3) paired phase sandwiched in between. We report (i) a new estimate for the location of a bicritical point and (ii) the first resolution of bimodal distributions in energy histograms at relatively low coupling strengths. We perform a flowgram analysis of the direct transition line with rescaling of the linear system size in order to obtain a data collapse. The data collapses up to coupling constants where we find bimodal distributions in energy histograms.Comment: 16 pages, 11 figures. Submitted to Physical Review

I/MLEs and the uneven return of pastoral power

Informed by the work of the work of Michel Foucault, Ian Hunter, and Ansgar Allen, this paper argues that I/MLEs are not the creation of a ‘modern’ or ‘innovative’ learning environment but rather the reclamation of an educational technique that was pioneered en masse almost two centuries ago (and based on practices many centuries older than that), where established pastoral methods were key to shaping particularly formed educated subjects. Drawing on work produced by the OECD, as well as UK and NZ education policies and school building design guidance, this argument couches two claims, the first of which is that whether or not education systems and school buildings are conforming to I/MLE models, the ubiquity of ideologically narrow conceptions of the learning subject are enforced regardless, through subtle or unsubtle means. However, the second claim is that, despite their overarching and unsurprising ideological homogeneity with other more outcome oriented forms of schooling, I/MLEs have the potential to offer a much more substantial formative experience than other schooling systems due to their implicit recovery of the traditional pastoral aspect of education

The Future of Institutional Listening:Conversation in the Cracks of the University

Listening to students is not only often a deficiency in educational theory, but also for educational leaders, policy-makers, teachers, parents, and educational actors in society more broadly. This article outlines this problem while suggesting that educational conversations that occur "within" the context of institutions can afford particular benefits to their participants and the institutions themselves. Topics of interest specific to the institutional experience of individuals, including those that are highly critical of them, can be developed in non-linear and non-efficiency-orientated directions, in a manner that is both individualised and pluralistic