Quantum Corrections to Q-Balls

We extend calculational techniques for static solitons to the case of field configurations with simple time dependence in order to consider quantum effects on the stability of Q-balls. These nontopological solitons exist classically for any fixed value of an unbroken global charge Q. We show that one-loop quantum effects can destabilize very small Q-balls. We show how the properties of the soliton are reflected in the associated scattering problem, and find that a good approximation to the full one-loop quantum energy of a Q-ball is given by $\omega - E_0$, where $\omega$ is the frequency of the classical soliton's time dependence, and $E_0$ is the energy of the lowest bound state in the associated scattering problem.Comment: 6 pages, 2 figures, uses RevTex4; v2: replaced figure

An exploration of how young people who have offended conceptualise the term ‘family’

This research project aimed to explore how young people who have offended conceptualise the term ‘family’. This was important because ‘family’ has played a central role in policy, theory and research concerning young people who have offended; however, children and young people’s understandings and experiences of ‘family’ has largely been ignored in policy and research that concerns them. Following a grounded theory methodology (GTM) a policy document analysis was conducted to explore how the term ‘family’ has been constructed and defined in policy that concerns young people who have offended. Then, primary data was generated in collaboration with young people to further understand how they conceptualise the term ‘family’, and in essence, what this word means to them. Using questionnaires and focus groups, this facilitated discussions with the young people to discuss the meaning of ‘family’ at their own pace and in the presence of peers from a similar background. The young people who participated in this research were chosen due to their offender status in the youth justice system (YJS), however, many of them also chose to self-report experience of being a looked after child (LAC). The young people were drawn from two geographical locations: London and Glasgow. Key themes that were drawn from the empirical research identified that the young people placed more emphasis on the emotional aspects of ‘family life’ than on the presence of specific ‘family members’. The discussions centred around the importance of love, trust and safety, in determining who should be considered ‘family’, which was significantly different to much of the previous research reviewed. Therefore, this thesis presents an original contribution to knowledge, that young people who have offended use a variety of diverse and flexible ways to conceptualise the term ‘family’. The language used to describe the term ‘family’ was largely based on their own personal experiences of ‘family’ and ‘family life’, which for some of the young people, was significantly affected by their time spent in the care system. The findings from this research not only provide an original contribution to knowledge in the varied and dynamic ways in which young people who have offended choose to describe and define the term ‘family’, but the findings also complement and add to the emerging but limited evidence-base of research that seeks to place children and young people’s voices at the centre

A Kondo impurity in a disordered metal: Anderson's theorem revisited

We consider a local moment which is coupled by a non-random Kondo $J$ to a band of conduction electrons in a random potential. We prove an analog of Anderson's theorem in a large-N limit of this model. The theorem states that when the disorder is weak, the disorder-averaged low-temperature thermodynamics is independent of the strength of the disorder; remarkably, it further states that fluctuation effects in the long-time limit are {\it independent even of the realization of the disorder}. We discuss the relationship of this theorem to theoretical and experimental studies of similar problems.Comment: 4 pages, RevTe

Classical solution of the wave equation

The classical limit of wave quantum mechanics is analyzed. It is shown that the general requirements of continuity and finiteness to the solution $\psi(x)=Ae^{i\phi(x)}+ Be^{-i\phi(x)}$, where $\phi(x)=\frac 1\hbar W(x)$ and $W(x)$ is the reduced classical action of the physical system, result in the asymptote of the exact solution and general quantization condition for $W(x)$, which yields the exact eigenvalues of the system.Comment: 8 Pages, 10 Refs, LaTe

Inversion of polarimetric data from eclipsing binaries

We describe a method for determining the limb polarization and limb darkening of stars in eclipsing binary systems, by inverting photometric and polarimetric light curves. Because of the ill-conditioning of the problem, we use the Backus-Gilbert method to control the resolution and stability of the recovered solution, and to make quantitative estimates of the maximum accuracy possible. Using this method we confirm that the limb polarization can indeed be recovered, and demonstrate this with simulated data, thus determining the level of observational accuracy required to achieve a given accuracy of reconstruction. This allows us to set out an optimal observational strategy, and to critcally assess the claimed detection of limb polarization in the Algol system. The use of polarization in stars has been proposed as a diagnostic tool in microlensing surveys by Simmons et al. (1995), and we discuss the extension of this work to the case of microlensing of extended sources.Comment: 10pp, 5 figures. To appear in A&

Hidden Order in URu2Si2URu_2Si_2

We review current attempts to characterize the underlying nature of the hidden order in $URu_2Si_2$. A wide variety of experiments point to the existence of two order parameters: a large primary order parameter of unknown character which co-exists with secondary antiferromagnetic order. Current theories can be divided into two groups determined by whether or not the primary order parameter breaks time-reversal symmetry. We propose a series of experiments designed to test the time-reversal nature of the underlying primary order in $URu_2Si_2$ and to characterize its local single-ion physics

The Role Of Local Authorities In Health Issues: A Policy Document Analysis

Prior to the passing of the Health and Social Care Act 2012 the Communities and Local Government (CLG) Select Committee conducted an investigation into the proposed changes to the Public Health System in England. The Committee considered 40 written submissions and heard oral evidence from 26 expert witnesses. Their report, which included complete transcripts of both oral and written submissions, provided a rich and informed data on which to base an analysis of the proposed new public health system. This report analyses the main themes that emerged from the evidence submissions and forms part of our preliminary work for PRUComm’s PHOENIX project examining the development of the new public health system

Extending Elliptic Curve Chabauty to higher genus curves

We give a generalization of the method of "Elliptic Curve Chabauty" to higher genus curves and their Jacobians. This method can sometimes be used in conjunction with covering techniques and a modified version of the Mordell-Weil sieve to provide a complete solution to the problem of determining the set of rational points of an algebraic curve $Y$.Comment: 24 page

The Kondo lattice model from strong-coupling viewpoint

We present some preliminary results on the phase diagram of the 2D S=1/2 Kondo lattice model at finite doping. As a starting point the Hamiltonian is written in terms of local spin and charge excitations, and the interactions between these modes are subsequently treated in various perturbative schemes. We find that a paramagnetic-magnetic quantum phase transition does occur, and, at least on a superficial level, the Kondo effect does not break down at the critical point. The latter result however might well be a consequence of the inherent bias of our starting point and/or the level of approximation.Comment: 4 pages, to appear in the Proceedings of SCES 2001, Ann Arbor, August 200