Perturbative Effective Theory in an Oscillator Basis?

The effective interaction/operator problem in nuclear physics is believed to be highly nonperturbative, requiring extended high-momentum spaces for accurate solution. We trace this to difficulties that arise at both short and long distances when the included space is defined in terms of a basis of harmonic oscillator Slater determinants. We show, in the simplest case of the deuteron, that both difficulties can be circumvented, yielding highly perturbative results in the potential even for modest (~6hw) included spaces.Comment: 10 pages, 4 figure

Therapist and client experiences of art therapy in relation to psychosis: a thematic analysis

Background: Evidenced-based theory of art therapy for people experiencing psychosis is relatively under-developed, especially in terms of the detail of what happens in art therapy sessions, and the role of the artmaking. Aims: To explore in-session processes of art therapy from the viewpoint of both service users and art therapists using reflexive thematic analysis. Method: Twelve participants, six service users and six art therapists, were interviewed. Results: From the analysis, four main themes were created, specifically ‘safe space’, ‘power of artmaking’, ‘challenges’ and ‘supporting recovery’. Conclusions: The findings offer triangulated themes from art therapists and service users and explicate the role of the artmaking. Artmaking offers service users a space to express and contain their feelings, needs, wishes and fears within the artwork. This can start a dialogue and provides them with an opportunity to shift how they view their artwork and themselves. Practice implications: Artmaking helps service users express non-verbal and embodied material, which could then be explored through a therapeutic dialogue. Service users who struggle with verbalising their thoughts and feelings may particularly benefit from art therapy

6J Symbols Duality Relations

It is known that the Fourier transformation of the square of (6j) symbols has a simple expression in the case of su(2) and U_q(su(2)) when q is a root of unit. The aim of the present work is to unravel the algebraic structure behind these identities. We show that the double crossproduct construction H_1\bowtie H_2 of two Hopf algebras and the bicrossproduct construction H_2^{*}\lrbicross H_1 are the Hopf algebras structures behind these identities by analysing different examples. We study the case where D= H_1\bowtie H_2 is equal to the group algebra of ISU(2), SL(2,C) and where D is a quantum double of a finite group, of SU(2) and of U_q(su(2)) when q is real.Comment: 28 pages, 2 figure

Area Regge Calculus and Discontinuous Metrics

Taking the triangle areas as independent variables in the theory of Regge calculus can lead to ambiguities in the edge lengths, which can be interpreted as discontinuities in the metric. We construct solutions to area Regge calculus using a triangulated lattice and find that on a spacelike hypersurface no such discontinuity can arise. On a null hypersurface however, we can have such a situation and the resulting metric can be interpreted as a so-called refractive wave.Comment: 18 pages, 1 figur