32,428 research outputs found
On superconformal anyons
In d=2+1 dimensions, there exist field theories which are non-relativistic
and superconformal. These theories describe two species of anyons, whose spins
differ by 1/2, interacting in a harmonic trap. We compute the dimensions of
chiral primary operators. These operators receive large anomalous dimensions
which are related to the unusual angular momentum properties of anyons.
Surprisingly, we find that the dimensions of some chiral primary operators
violate the unitarity bound and we trace this to the fact that the associated
wavefunctions become non-normalisable. We also study BPS non-perturbative
states in this theory: these are Jackiw-Pi vortices. We show that these emerge
at exactly the point where perturbative operators hit the unitarity bound. To
describe the low-energy dynamics of these vortices, we construct a novel type
of supersymmetric gauged linear sigma model.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/JHEP01(2016)13
A matrix model for WZW
We study a U(N) gauged matrix quantum mechanics which, in the large N limit,
is closely related to the chiral WZW conformal field theory. This manifests
itself in two ways. First, we construct the left-moving Kac-Moody algebra from
matrix degrees of freedom. Secondly, we compute the partition function of the
matrix model in terms of Schur and Kostka polynomials and show that, in the
large limit, it coincides with the partition function of the WZW model.
This same matrix model was recently shown to describe non-Abelian quantum Hall
states and the relationship to the WZW model can be understood in this
framework.Science and Technology Facilities Council; European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013), ERC grant agreement STG 279943, “Strongly Coupled Systems”This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/JHEP08(2016)00
What are the holistic care impacts among individuals living through the COVID-19 pandemic in residential or community care settings? An integrative systematic review.
The objective of this study was to critically synthesise evidence in relation to the holistic care impacts (physical, psychological, social, spiritual and environmental well-being) among individuals living in residential aged-care facilities (RACFs) with restrictions during the COVID-19 pandemic. An integrative systematic review followed a pre-registered protocol and has been reported according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) Guidelines. Electronic databases were searched from inception to June 2022. Qualitative, quantitative and mixed methods studies were included. All articles were double-screened according to a pre-determined eligibility criterion. The review process was managed using Covidence systematic review software. Data from the studies were extracted, methodological quality appraisal conducted and a narrative synthesis conducted. 18 studies were included. The impact of restrictive practices and periods of lockdown impacted older people on all levels of individual quality-of-life. With or without COVID-19, residents experienced functional decline and many experienced malnutrition, increased incontinence, increased pain, and poorer general health and significant psychological distress. Depression increased with reduced social contact, as did anxiety and loneliness. Some residents spoke of suicidal ideation. It is highly plausible that further outbreaks may prompt knee-jerk reactions from public health departments and governing bodies to continue to restrict and lockdown facilities. Public health COVID-19 outbreak policy for aged care across the globe will need to consider the benefits verses risk debate, given the findings uncovered in this review. These findings showed that it is vital that policy considers quality-of-life domains - not solely survival rates
Predicted efficiency of Si wire array solar cells
Solar cells based on arrays of CVD-grown Si nano- or micro-wires have attracted interest as potentially low-cost alternatives to conventional wafer-based Si photovoltaics [1-6], and single-wire solar cells have been reported with efficiencies of up to 3.4% [7]. We recently presented device physics simulations which predicted efficiencies exceeding 17%, based on experimentally observed diffusion lengths within our wires [8]. However, this model did not take into account the optical properties of a wire array device - in particular the inherently low packing fraction of wires within CVD-grown wire arrays, which might limit their ability to fully absorb incident sunlight. For this reason, we have combined a device physics model of Si wire solar cells with FDTD simulations of light absorption within wire arrays to investigate the potential photovoltaic efficiency of this cell geometry. We have found that even a sparsely packed array (14%) is expected to absorb moderate (66%) amounts of above-bandgap solar energy, yielding a simulated photovoltaic efficiency of 14.5%. Because the wire array comprises such a small volume of Si, the observed absorption represents an effective optical concentration, which enables greater operating voltages than previously predicted for Si wire array solar cells
Determinants of club head speed in PGA professional golfers
Club head speed (CHS) has been significantly correlated to golf performance, but only in amateurs. The purpose of this study therefore, was to investigate the relationship between field-based measures of strength and power with CHS in PGA professional golfers, and further, determine differences between age groups. A correlation design was used to test relationships between squat jump (SJ), seated medicine ball throw (SMBT), rotational medicine ball throw (RMBT) and CHS. Twenty participants volunteered to take part in the study (age: 31.95 +/- 8.7 years, height: 182.75 +/- 6.88cm, mass: 90.47 +/- 15.6kg). Intraclass correlation coefficients reported high reliability for performance variables (r = 0.85-0.95). Significant correlations (p 30 (n = 10; 39.7 +/- 5.5 years). Correlations to CHS for 30 also had significant correlations to CHS in SMBT (r = 0.881) and SJ (r = 0.729), but also in RMBT (r = 0.642). The results of this study suggest that SJ and SMBT have the largest contribution to CHS in PGA professional golfers. When comparing age groups, it appears that younger golfers ( 30 years) utilise more upper body strength. Results suggest that strength based leg exercises and power based chest exercises may improve CHS in professional golfers
Electron heating mechanisms in dual frequency capacitive discharges
We discuss electron heating mechanisms in the sheath regions of dual-frequency capacitive discharges, with the twin aims of identifying the dominant mechanisms and supplying closed-form expressions from which the heating power can be estimated. We show that the heating effect produced by either Ohmic or collisionless heating is much larger when the discharge is excited by a superposition of currents at two frequencies than if either current had acted alone. This coupling effect occurs because the lower frequency current, while not directly heating the electrons to any great extent, strongly affects the spatial structure of the discharge in the sheath regions
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