Remarks on the Heavy Quark Potential in the Supergravity Approach

We point out certain unexpected features of the planar QCD3 confining potential, as computed from a classical worldsheet action in an AdS metric via the Maldacena conjecture. We show that there is no Luscher c/R term in the static-quark potential, which is contrary to both the prediction of various effective string models, and the results of some recent lattice Monte Carlo studies. It is also noted that the glueball masses extracted from classical supergravity tend to finite, coupling-independent constants in the strong coupling limit, even as the string tension tends to infinity in the same limit; this is a counter-intuitive result.Comment: 10 pages, 2 figures, Latex2e. Some additional remarks added concerning worldsheet fluctuations in AdS spac

‘Ecstasy’ and the use of sleep medications in a general community sample: a four-year follow-up

Aims: Animal models show that a single dose of MDMA (‘ecstasy’) can result in long-term disruption of sleep. We evaluated the relationship between ecstasy consumption and the use of sleep medications in humans after controlling for key factors. Design: The Personality and Total Health Through Life project uses a longitudinal cohort with follow-up every four years. This study reports data from waves two and three. Setting: Participants were recruited from the electoral roll in the Australian Capital Territory and Queanbeyan, New South Wales, Australia. Participants: Participants were aged 20-24 years at wave one (1999-2000). Measures: The study collected self-reported data on ecstasy, meth/amphetamine, cannabis, alcohol, tobacco and use of sleeping medications (pharmaceutical or other substances). Depression was categorised with the Brief Patient Health Questionnaire (BPHQ). Other psychosocial measures included lifetime traumas. We used generalised estimating equations to model outcomes. Results: Ecstasy data were available from 2128 people at wave two and 1977 at wave three: sleeping medication use was reported by 227 (10.7%) respondents at wave two and 239 (12.1%) at wave three. Increased odds ratios (OR) for sleeping medication use was found for those with depression (OR=1.88, (95% confidence interval (CI) 1.39, 2.53), women (OR=1.44, 95% CI 1.13, 1.84), and increased by 19% for each lifetime trauma. Ecstasy use was not a significant predictor, but >monthly versus never meth/amphetamine use increased the odds (OR=3.03, 95% CI 1.30, 7.03). Conclusion: The use of ecstasy was not associated with the use of sleeping medications controlling for other risk factors.The PATH study was supported by an NHMRC Program Grant 179805 and NHMRC Project Grant 157125. The sponsors had no role in the design, conduct or reporting of the research. None of the authors have connections (direct or indirect) with the tobacco, alcohol, pharmaceutical or gaming industries or any body substantially funded by one of these organisations

From Doubled Chern-Simons-Maxwell Lattice Gauge Theory to Extensions of the Toric Code

We regularize compact and non-compact Abelian Chern-Simons-Maxwell theories on a spatial lattice using the Hamiltonian formulation. We consider a doubled theory with gauge fields living on a lattice and its dual lattice. The Hilbert space of the theory is a product of local Hilbert spaces, each associated with a link and the corresponding dual link. The two electric field operators associated with the link-pair do not commute. In the non-compact case with gauge group $\mathbb{R}$, each local Hilbert space is analogous to the one of a charged "particle" moving in the link-pair group space $\mathbb{R}^2$ in a constant "magnetic" background field. In the compact case, the link-pair group space is a torus $U(1)^2$ threaded by $k$ units of quantized "magnetic" flux, with $k$ being the level of the Chern-Simons theory. The holonomies of the torus $U(1)^2$ give rise to two self-adjoint extension parameters, which form two non-dynamical background lattice gauge fields that explicitly break the manifest gauge symmetry from $U(1)$ to $\mathbb{Z}(k)$. The local Hilbert space of a link-pair then decomposes into representations of a magnetic translation group. In the pure Chern-Simons limit of a large "photon" mass, this results in a $\mathbb{Z}(k)$-symmetric variant of Kitaev's toric code, self-adjointly extended by the two non-dynamical background lattice gauge fields. Electric charges on the original lattice and on the dual lattice obey mutually anyonic statistics with the statistics angle $\frac{2 \pi}{k}$. Non-Abelian $U(k)$ Berry gauge fields that arise from the self-adjoint extension parameters may be interesting in the context of quantum information processing.Comment: 38 pages, 4 figure

From the SU(2)SU(2) Quantum Link Model on the Honeycomb Lattice to the Quantum Dimer Model on the Kagom\'e Lattice: Phase Transition and Fractionalized Flux Strings

We consider the $(2+1)$-d $SU(2)$ quantum link model on the honeycomb lattice and show that it is equivalent to a quantum dimer model on the Kagom\'e lattice. The model has crystalline confined phases with spontaneously broken translation invariance associated with pinwheel order, which is investigated with either a Metropolis or an efficient cluster algorithm. External half-integer non-Abelian charges (which transform non-trivially under the $\mathbb{Z}(2)$ center of the $SU(2)$ gauge group) are confined to each other by fractionalized strings with a delocalized $\mathbb{Z}(2)$ flux. The strands of the fractionalized flux strings are domain walls that separate distinct pinwheel phases. A second-order phase transition in the 3-d Ising universality class separates two confining phases; one with correlated pinwheel orientations, and the other with uncorrelated pinwheel orientations.Comment: 16 pages, 20 figures, 2 tables, two more relevant references and one short paragraph are adde

From the SU(2)SU(2) Quantum Link Model on the Honeycomb Lattice to the Quantum Dimer Model on the Kagom\'e Lattice: Phase Transition and Fractionalized Flux Strings

We consider the $(2+1)$-d $SU(2)$ quantum link model on the honeycomb lattice and show that it is equivalent to a quantum dimer model on the Kagom\'e lattice. The model has crystalline confined phases with spontaneously broken translation invariance associated with pinwheel order, which is investigated with either a Metropolis or an efficient cluster algorithm. External half-integer non-Abelian charges (which transform non-trivially under the $\mathbb{Z}(2)$ center of the $SU(2)$ gauge group) are confined to each other by fractionalized strings with a delocalized $\mathbb{Z}(2)$ flux. The strands of the fractionalized flux strings are domain walls that separate distinct pinwheel phases. A second-order phase transition in the 3-d Ising universality class separates two confining phases; one with correlated pinwheel orientations, and the other with uncorrelated pinwheel orientations.Comment: 16 pages, 20 figures, 2 tables, two more relevant references and one short paragraph are adde

Low-Information Radiation Imaging using Rotating Scatter Mask Systems and Neural Network Algorithms

While recent studies have demonstrated the directional capabilities of the single-detector rotating scatter mask (RSM) system for discrete, dual-particle environments, there has been little progress towards adapting it as a true imaging device. In this research, two algorithms were developed and tested using an RSM mask design previously optimized for directional detection and simulated 137Cs signals from a variety of source distributions. The first, maximum-likelihood expectation-maximization (ML-EM), was shown to generate noisy images, with relatively low accuracy (145% average relative error) and signal-to-noise ratio (0.27) for most source distributions simulated. The second, a novel regenerative neural network (ReGeNN), performed exceptionally well, with significantly higher accuracy (33\% average relative error) over all source types compared to ML-EM and drastically improved signal-to-noise ratio (0.85) in the reconstructed images. The imaging capabilities of ReGeNN were then experimentally validated using an additively-manufactured mask. Measuring two point and one ring 22Na source distributions, a modified ReGeNN was able to successfully train on simulated noisy signals and accurately predict the relative size and direction of the three sources. To support future design optimizations to overcome current limitations of the current mask design, a ray tracing algorithm was also developed as an alternative to more rigorous Monte Carlo RSM simulations. This ray tracing code was shown to significantly improve computational efficiency, at a slight cost to the simulated signal accuracy for more complex mask designs

Impact of Intellectual Property Contract Language on University-Industry Research Consortia

Interactions and collaborations between research universities and industry have a potential to provide significant benefits to both. For universities, these interactions and collaborations can bring additional revenues through license fees or additional research funds, promote economic development in their community, test the practical application of their research, allow for the input of industry on the research, create internships and employment opportunities for students, and-in general-further the research, education, and outreach aspects of their mission. For industry, university interactions and collaborations offer the potential of access to intellectual property (IP) to commercialize, research results that can shape their research and development agenda, faculty and students, students for internships and jobs, and allows for the supporting of basic research (Lee, 2000). The problem university administrators face is how to facilitate these • university-industry collaborations. One means is active engagement. Active engagement brings multiple faculty members together with multiple members of industry to work on a focused area of technology within a research consortia. While the concept of a research consortia is almost universally of interest when described to industry, getting companies to join the consortia is difficult. The stumbling block is often how IP, if it is generated, will be shared. The focus of the study was the examination one aspect of the IP sharing stumbling block, which is the impact of intellectual property regulatory language on university-industry collaborative research. This causal-comparative study explores the impact of intellectual property contract language on the development of patented research, paper publication, industrial research funding, and graduate students supported at the University of California Santa Cruz Storage Systems Research Center (UC SSRC) and the University of Minnesota Digital Technology Center Intelligent Storage Consortium (UM DISC). The hypothesis of the study was that consortia without IP language in their consortia agreements are more successful than those with IP language. Success, for the purpose of this study, was measured by the number of patent disclosures, research papers produced, amount of industrial research funding, number of graduate students supported, and a measurement of direct industry participation in the consortium. The findings indicated that UC SSRC, which does not have IP language in its member agreement, was more successful than UM DISC in terms of publications, industrial research expenditures, and graduate research assistants supported. In each of these areas, UC SSRC out performed UM DISC. In one area, number of patents produced, both had the same result. No patents were issued for either. The results of this study will be applied to the industrial collaboration models used by the University of Minnesota Digital Technology Center (DTC). In particular, it will result in the recommendation that a hybrid approach to university-industry active engagement be developed which would allow industrial partners to join a consortium and share in the IP, join the consortium through a gift, or purchase the services of the consortium for a specific project with IP ownership transferred to the industrial partner