Green Functions for the Wrong-Sign Quartic

It has been shown that the Schwinger-Dyson equations for non-Hermitian theories implicitly include the Hilbert-space metric. Approximate Green functions for such theories may thus be obtained, without having to evaluate the metric explicitly, by truncation of the equations. Such a calculation has recently been carried out for various $PT$-symmetric theories, in both quantum mechanics and quantum field theory, including the wrong-sign quartic oscillator. For this particular theory the metric is known in closed form, making possible an independent check of these approximate results. We do so by numerically evaluating the ground-state wave-function for the equivalent Hermitian Hamiltonian and using this wave-function, in conjunction with the metric operator, to calculate the one- and two-point Green functions. We find that the Green functions evaluated by lowest-order truncation of the Schwinger-Dyson equations are already accurate at the (6-8)% level. This provides a strong justification for the method and a motivation for its extension to higher order and to higher dimensions, where the calculation of the metric is extremely difficult

Design Margins: Impact on Building Energy Performance

This paper examines the addition of design margins for building services energy infrastructure during the design process. It argues that care must be taken when applying margins; ensuring cumulative effects do not undermine the ability of systems to be energy efficient. An example of a hospital Trust is provided showing the addition of design margins impacting the energy efficiency of services provided. Tensions are found between delivery of flexibility, adaptability and other change parameters and the need for the system to be bounded, so as to encourage effectiveness

How do Multinationals Build Social Capital? Evidence from South Africa.

This paper looks at the self-reporting of social engagement by multinational firms in South Africa, developing previous measures of social capital to fit the unique context of the multinational firm in particular mapping the configurations of declared engagement and the firms' provision. It finds large intersectoral variation which cannot be predicted by one factor alone, and sometimes wide intrasectoral variation. In particular (and for different reasons) 'extractive' and 'industrial' sector firms traditionally criticised for their impact on communities - and 'medical' sector firms are engaged in practices conducive to the generation of social capital.Social Capital, Corporate Social Responsibility, Business Ethics, South Africa, Multinational Companies

Extending PT symmetry from Heisenberg algebra to E2 algebra

The E2 algebra has three elements, J, u, and v, which satisfy the commutation relations [u,J]=iv, [v,J]=-iu, [u,v]=0. We can construct the Hamiltonian H=J^2+gu, where g is a real parameter, from these elements. This Hamiltonian is Hermitian and consequently it has real eigenvalues. However, we can also construct the PT-symmetric and non-Hermitian Hamiltonian H=J^2+igu, where again g is real. As in the case of PT-symmetric Hamiltonians constructed from the elements x and p of the Heisenberg algebra, there are two regions in parameter space for this PT-symmetric Hamiltonian, a region of unbroken PT symmetry in which all the eigenvalues are real and a region of broken PT symmetry in which some of the eigenvalues are complex. The two regions are separated by a critical value of g.Comment: 8 pages, 7 figure

PT-Symmetry Quantum Electrodynamics--PTQED

The construction of $\mathcal{PT}$-symmetric quantum electrodynamics is reviewed. In particular, the massless version of the theory in 1+1 dimensions (the Schwinger model) is solved. Difficulties with unitarity of the $S$-matrix are discussed.Comment: 11 pages, 1 figure, contributed to Proceedings of 6th International Workshop on Pseudo-Hermitian Hamiltonians in Quantum Physic

Inductive Signals: Revolving vertebrates

AbstractAn old idea about the relationship between arthropod and vertebrate body plans has been given new life by studies of the signalling genes controlling dorsal and ventral development in Drosophila and Xenopus

Quantum Mechanics of the Doubled Torus

We investigate the quantum mechanics of the doubled torus system, introduced by Hull [1] to describe T-folds in a more geometric way. Classically, this system consists of a world-sheet Lagrangian together with some constraints, which reduce the number of degrees of freedom to the correct physical number. We consider this system from the point of view of constrained Hamiltonian dynamics. In this case the constraints are second class, and we can quantize on the constrained surface using Dirac brackets. We perform the quantization for a simple T-fold background and compare to results for the conventional non-doubled torus system. Finally, we formulate a consistent supersymmetric version of the doubled torus system, including supersymmetric constraints.Comment: 31 pages, 1 figure; v2: references added, minor corrections to final sectio

Generalised Geometry for M-Theory

Generalised geometry studies structures on a d-dimensional manifold with a metric and 2-form gauge field on which there is a natural action of the group SO(d,d). This is generalised to d-dimensional manifolds with a metric and 3-form gauge field on which there is a natural action of the group $E_{d}$. This provides a framework for the discussion of M-theory solutions with flux. A different generalisation is to d-dimensional manifolds with a metric, 2-form gauge field and a set of p-forms for $p$ either odd or even on which there is a natural action of the group $E_{d+1}$. This is useful for type IIA or IIB string solutions with flux. Further generalisations give extended tangent bundles and extended spin bundles relevant for non-geometric backgrounds. Special structures that arise for supersymmetric backgrounds are discussed.Comment: 31 page

Superstring partition functions in the doubled formalism

Computation of superstring partition function for the non-linear sigma model on the product of a two-torus and its dual within the scope of the doubled formalism is presented. We verify that it reproduces the partition functions of the toroidally compactified type--IIA and type--IIB theories for appropriate choices of the GSO projection.Comment: 15 page

Guided self-help cognitive behavioral intervention for VoicEs (GiVE): study protocol for a pilot randomized controlled trial

Background: Cognitive behavior therapy for psychosis (CBTp) is an effective intervention for people who hear distressing voices (auditory hallucinations). However, there continues to be a problem of poor access to CBTp. Constraints on health care funding require this problem to be addressed without a substantial increase in funding. One solution is to develop guided self-help forms of CBTp to improve access, and a symptom-specific focus on, for example, distressing voices (auditory verbal hallucinations) has the potential to enhance effectiveness. We term this cognitive behavior therapy for distressing voices (CBTv). Methods/design: This trial is an external pilot randomized controlled trial comparing the effects of 12 week guided self-help CBTv (with eight therapist support sessions) with a wait list control condition. Informed consent will be obtained from each participant. Half of the 30 participants will be randomized to receive guided self-help CBTv immediately; the remaining half will receive the intervention after a 12-week delay. All participants will continue with their usual treatment throughout the study. Outcomes will be assessed using questionnaires completed at baseline and 12 weeks postrandomization. Interviews will be offered to all those who receive therapy immediately to explore their experiences with the intervention. Discussion: The outcomes of this trial, both quantitative and qualitative, will inform the design of a definitive randomized controlled trial of guided self-help CBTv. If this intervention is effective, it could help to increase access to CBT for those who hear distressing voices