Squeezed states: A geometric framework

A general definition of squeezed states is proposed and its main features are illustrated through a discussion of the standard optical coherent states represented by 'Gaussian pure states'. The set-up involves representations of groups on Hilbert spaces over homogeneous spaces of the group, and relies on the construction of a square integrable (coherent state) group representation modulo a subgroup. This construction depends upon a choice of a Borel section which has a certain permissible arbitrariness in its selection; this freedom is attributable to a squeezing of the defining coherent states of the representation, and corresponds in this way to a sort of gauging

Occupational Learning, Financial Knowledge, and the Accumulation of Retirement Wealth

This study explores the relationship between general human capital investment, financial knowledge, occupational spillovers, and the accumulation of wealth in a primarily descriptive manner. Drawing upon human capital theory and following previous related work by Delavande, Rohwedder and Willis (2008), we hypothesized that individuals with daily exposure to financial knowledge through their occupation would benefit by having greater financial knowledge that would translate into greater wealth accumulation than individuals who do not enjoy such spillovers from their occupation. Using data from the Cognitive Economics Study and the Health and Retirement Study, we find strong evidence that individuals in financial occupations tend to have greater financial knowledge and moderate evidence that they also have greater wealth accumulation.

The impact of a post-take ward round pharmacist on the risk score and enactment of medication-related recommendations

There is a scarcity of published research describing the impact of a pharmacist on the post-take ward round (PTWR) in addition to ward-based pharmacy services. The aim of this paper was to evaluate the impact of clinical pharmacists' participation on the PTWR on the risk assessment scores of medication-related recommendations with and without a pharmacist. This includes medication-related recommendations occurring on the PTWR and those recommendations made by the ward-based pharmacist on the inpatient ward. A pre-post intervention study was undertaken that compared the impact of adding a pharmacist to the PTWR compared with ward-based pharmacist services alone. A panel reviewed the risk of not acting on medication recommendations that was made on the PTWR and those recorded by the ward-based pharmacist. The relationship between the risk scores and the number and proportion of recommendations that led to action were compared between study groups. There were more medication-related recommendations on the PTWR in the intervention group when a pharmacist was present. Proportionately fewer were in the 'very high and extreme' risk category. Although there was no difference in the number of ward pharmacist recommendations between groups, there was a significantly higher proportion of ward pharmacist recommendations in the "very high and extreme" category in those patients who had been seen on a PTWR attended by a pharmacist than when a pharmacist was not present. There were a greater proportion of "low and medium" risk actionable medication recommendations actioned on the PTWR in the intervention group; and no difference in the risk scores in ward pharmacist recommendations actioned between groups. Overall, the proportion of recommendations that were actioned was higher for those made on the PTWR compared with the ward. The addition of a pharmacist to the PTWR resulted in an increase in low, medium, and high risk recommendations on the PTWR, more very high and extreme risk recommendations made by the ward-based pharmacist, plus an increased number of recommendations being actioned during the patients' admission

Decoherence-free quantum-information processing using dipole-coupled qubits

We propose a quantum-information processor that consists of decoherence-free logical qubits encoded into arrays of dipole-coupled qubits. High-fidelity single-qubit operations are performed deterministically within a decoherence-free subsystem without leakage via global addressing of bichromatic laser fields. Two-qubit operations are realized locally with four physical qubits, and between separated logical qubits using linear optics. We show how to prepare cluster states using this method. We include all non-nearest-neighbor effects in our calculations, and we assume the qubits are not located in the Dicke limit. Although our proposal is general to any system of dipole-coupled qubits, throughout the paper we use nitrogen-vacancy (NV) centers in diamond as an experimental context for our theoretical results.Comment: 7 pages, 5 figure

Upper Extremity Biomechanics of Children with Spinal Cord Injury during Wheelchair Mobility

While much work is being done evaluating the upper extremity joint dynamics of adult manual wheelchair propulsion, limited work has examined the pediatric population of manual wheelchair users. Our group used a custom pediatric biomechanical model to characterize the upper extremity joint dynamics of 12 children and adolescents with spinal cord injury (SCI) during wheelchair propulsion. Results show that loading appears to agree with that of adult manual wheelchair users, with the highest loading primarily seen at the glenohumeral joint. This is concerning due to the increased time of wheelchair use in the pediatric population and the impact of this loading during developmental years. This research may assist clinicians with improved mobility assessment methods, wheelchair prescription, training, and long-term care of children with orthopaedic disabilities

Transverse instability for non-normal parameters

We consider the behaviour of attractors near invariant subspaces on varying a parameter that does not preserve the dynamics in the invariant subspace but is otherwise generic, in a smooth dynamical system. We refer to such a parameter as ``non-normal''. If there is chaos in the invariant subspace that is not structurally stable, this has the effect of ``blurring out'' blowout bifurcations over a range of parameter values that we show can have positive measure in parameter space. Associated with such blowout bifurcations are bifurcations to attractors displaying a new type of intermittency that is phenomenologically similar to on-off intermittency, but where the intersection of the attractor by the invariant subspace is larger than a minimal attractor. The presence of distinct repelling and attracting invariant sets leads us to refer to this as ``in-out'' intermittency. Such behaviour cannot appear in systems where the transverse dynamics is a skew product over the system on the invariant subspace. We characterise in-out intermittency in terms of its structure in phase space and in terms of invariants of the dynamics obtained from a Markov model of the attractor. This model predicts a scaling of the length of laminar phases that is similar to that for on-off intermittency but which has some differences.Comment: 15 figures, submitted to Nonlinearity, the full paper available at http://www.maths.qmw.ac.uk/~eo

Upper Extremity Biomechanical Model for Evaluation of Pediatric Joint Demands during Wheelchair Mobility

Current methods for evaluating upper extremity (UE) dynamics during pediatric wheelchair use are limited. We propose a new model to characterize UE joint kinematics and kinetics during pediatric wheelchair mobility. The bilateral model is comprised of the thorax, clavicle, scapula, upper arm, forearm, and hand segments. The modeled joints include: sternoclavicular, acromioclavicular, glenohumeral, elbow and wrist. The model is complete and is currently undergoing pilot studies for clinical application. Results may provide considerable quantitative insight into pediatric UE joint dynamics to improve wheelchair prescription, training and long term care of children with orthopaedic disabilities