Brick Walls and AdS/CFT

We discuss the relationship between the bulk-boundary correspondence in Rehren's algebraic holography (and in other 'fixed-background' approaches to holography) and in mainstream 'Maldacena AdS/CFT'. Especially, we contrast the understanding of black-hole entropy from the viewpoint of QFT in curved spacetime -- in the framework of 't Hooft's 'brick wall' model -- with the understanding based on Maldacena AdS/CFT. We show that the brick-wall modification of a Klein Gordon field in the Hartle-Hawking-Israel state on 1+2-Schwarzschild AdS (BTZ) has a well-defined boundary limit with the same temperature and entropy as the brick-wall-modified bulk theory. One of our main purposes is to point out a close connection, for general AdS/CFT situations, between the puzzle raised by Arnsdorf and Smolin regarding the relationship between Rehren's algebraic holography and mainstream AdS/CFT and the puzzle embodied in the 'correspondence principle' proposed by Mukohyama and Israel in their work on the brick-wall approach to black hole entropy. Working on the assumption that similar results will hold for bulk QFT other than the Klein Gordon field and for Schwarzschild AdS in other dimensions, and recalling the first author's proposed resolution to the Mukohyama-Israel puzzle based on his 'matter-gravity entanglement hypothesis', we argue that, in Maldacena AdS/CFT, the algebra of the boundary CFT is isomorphic only to a proper subalgebra of the bulk algebra, albeit (at non-zero temperature) the (GNS) Hilbert spaces of bulk and boundary theories are still the 'same' -- the total bulk state being pure, while the boundary state is mixed (thermal). We also argue from the finiteness of its boundary (and hence, on our assumptions, also bulk) entropy at finite temperature, that the Rehren dual of the Maldacena boundary CFT cannot itself be a QFT and must, instead, presumably be something like a string theory.Comment: 54 pages, 3 figures. Arguments strengthened in the light of B.S. Kay `Instability of Enclosed Horizons' arXiv:1310.739

Multi-black rings and the phase diagram of higher-dimensional black holes

Configurations of multiple concentric black rings play an important role in determining the pattern of branchings, connections and mergers between different phases of higher-dimensional black holes. We examine them using both approximate and (in five dimensions) exact methods. By identifying the role of the different scales in the system, we argue that it is possible to have multiple black ring configurations in which all the rings have equal temperature and angular velocity. This allows us to correct and improve in a simple, natural manner, an earlier proposal for the phase diagram of singly-rotating black holes in $D\geq 6$.Comment: 14 pages, 2 figure

Chronology protection in stationary three-dimensional spacetimes

We study chronology protection in stationary, rotationally symmetric spacetimes in 2+1 dimensional gravity, focusing especially on the case of negative cosmological constant. We show that in such spacetimes closed timelike curves must either exist all the way to the boundary or, alternatively, the matter stress tensor must violate the null energy condition in the bulk. We also show that the matter in the closed timelike curve region gives a negative contribution to the conformal weight from the point of view of the dual conformal field theory. We illustrate these properties in a class of examples involving rotating dust in anti-de Sitter space, and comment on the use of the AdS/CFT correspondence to study chronology protection.Comment: 20 pages. V2: minor corrections, Outlook expanded, references added, published versio

Perturbative Construction of Models of Algebraic Quantum Field Theory

We review the construction of models of algebraic quantum field theory by renormalized perturbation theory.Comment: 38 page

Quantitative and Qualitative Findings and Implications of an Intercultural Sensitivity Assessment Among Employees at a Large Health System

Tuesday, November 10, 2009: 2:45 PM Jarret R. Patton, MD , Department of Pediatrics, Lehigh Valley Health Network, Allentown, PA Jay Baglia, PhD , Department of Family Medicine, Lehigh Valley Health Network, Allentown, PA Lynn M. Deitrick, RN, PhD , Department of Community Health, Health Studies and Education, Lehigh Valley Health Network, Allentown, PA Anthony Nerino, MA , Department of Community Health, Health Studies and Education, Lehigh Valley Health Network, Allentown, PA Eric J. Gertner, MD, MPH , Department of Medicine, Lehigh Valley Health Network, Allentown, PA Judith N. Sabino, MPH , Cultural Awareness, Lehigh Valley Health Network, Allentown, PA MaryKay Grim, BS , Human Resources, Lehigh Valley Health Network, Allentown, PA Debbie Salas-Lopez, MD, MPH , Department of Medicine, Lehigh Valley Health Network, Allentown, PABackground: As our nation welcomes people from many cultures, it is essential that healthcare providers understand the cultural background of their patients. In response to this diversity, community hospitals are systematically strengthening and improving services to address the cultural needs of their multi-cultural patient populations. As part of a multi-faceted, system-wide cultural awareness initiative, our health network conducted a baseline intercultural sensitivity assessment of its employees. Research Objectives: To establish measures of intercultural sensitivity among employees through the use of a validated instrument. Population: 9,000+ physicians, nurses, technicians and non-clinical employees of a large health network in mid-Eastern Pennsylvania. Methods: All employees were invited to complete the IRB-reviewed, web-based Intercultural Sensitivity Scale (Chen and Starosta 2000). The ICS scale measures attitudes about interacting with people from different cultural backgrounds. The five sub-scales include: 1) interaction engagement, 2) respect for cultural differences, 3) interaction confidence, 4) interaction enjoyment, and 5) interaction attentiveness. Three open-ended questions asked how the network could enhance cultural sensitivity. Two other questions asked for learning preferences (i.e., e-learning, Grand Rounds) and topic information (i.e. diet, religious practices). Demographic information (i.e., age, position, years of service hospital) was also acquired. Results and Conclusions: A 35% (n=3446) response rate was achieved. Characteristics of the respondent sample were highly similar across age, length of employment, racial and ethnic status, gender and proportions of staff positions. With regard to two of the five sub-scales, the survey revealed relative strength in interaction enjoyment while respect for cultural differences exposed an interesting bi-modal distribution – with many staff achieving perfect scores in this area and another large contingent scoring well below the mean. Baseline measures informed educational interventions, assessed training needs, enabled evaluation of interventions, and revealed individual and/or institutional factors that impeded or enhanced responses to patient experiences of healthcare disparities. Initial findings suggest general staff preferences for diversity workshops and cultural fact sheets as the preferred mode of instruction. Employees requested information about religion, attitudes about death and dying, and attitudes about health care institutions relevant to cultures represented in our local community. Practice Implications: Baseline results are used to direct network initiatives (i.e. creating health information repository, ensuring language-appropriate services, and strengthening educational programs) and to measure intervention outcomes. Along with obtaining uniform racial/ethnic patient data, this information is essential in comprehensive organizational change regarding culturally-appropriate service delivery and will ensure the delivery of equitable health care. Learning Objectives: 1. Explain how quantitative and qualitative results inform system-wide planning related to cultural competency. 2. List the key findings from this assessment 3. Describe a research methodology to measure the intercultural sensitivity of a health care organization employee population. Keywords:Cultural Competency, Hospitals Presenting author\u27s disclosure statement: Qualified on the content I am responsible for because: I am co-chair of Lehigh Valley Health Network\u27s Cultural Awareness Initiative. The abstract describes a baseline assessment that was part of this initiative. Any relevant financial relationships? No I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation

Quantum fields during black hole formation: how good an approximation is the Unruh state?

We study the quantum effects of a test Klein-Gordon field in a Vaidya space-time consisting of a collapsing null shell that forms a Schwazschild black hole, by explicitly obtaining, in a (1 + 1)-dimensional model, the Wightman function, the renormalised stress-energy tensor, and by analysing particle detector rates along stationary orbits in the exterior black hole region, and make a comparison with the folklore that the Unruh state is the state that emerges from black hole formation. In the causal future of the shell, we find a negative ingoing flux at the horizon that agrees precisely with the Unruh state calculation, and is the source of black hole radiation, while in the future null infinity we find that the radiation flux output in the Unruh state is an upper bound for the positive outgoing flux in the collapsing null shell spacetime. This indicates that back-reaction estimates based on Unruh state calculations over-estimate the energy output carried by so-called pre-Hawking radiation. The value of the output predicted by the Unruh state is however approached exponentially fast. Finally, we find that at late times, stationary observers in the exterior black hole region in the collapsing shell spacetime detect the local Hawking temperature, which is also well characterised by the Unruh state, coming from right-movers. Early-time discrepancies between the detector rates for the Unruh state and for the state in the collapsing shell spacetime are explored numerically

Effects of gestational age at birth on cognitive performance : a function of cognitive workload demands

Objective: Cognitive deficits have been inconsistently described for late or moderately preterm children but are consistently found in very preterm children. This study investigates the association between cognitive workload demands of tasks and cognitive performance in relation to gestational age at birth. Methods: Data were collected as part of a prospective geographically defined whole-population study of neonatal at-risk children in Southern Bavaria. At 8;5 years, n = 1326 children (gestation range: 23–41 weeks) were assessed with the K-ABC and a Mathematics Test. Results: Cognitive scores of preterm children decreased as cognitive workload demands of tasks increased. The relationship between gestation and task workload was curvilinear and more pronounced the higher the cognitive workload: GA2 (quadratic term) on low cognitive workload: R2 = .02, p<0.001; moderate cognitive workload: R2 = .09, p<0.001; and high cognitive workload tasks: R2 = .14, p<0.001. Specifically, disproportionally lower scores were found for very (<32 weeks gestation) and moderately (32–33 weeks gestation) preterm children the higher the cognitive workload of the tasks. Early biological factors such as gestation and neonatal complications explained more of the variance in high (12.5%) compared with moderate (8.1%) and low cognitive workload tasks (1.7%). Conclusions: The cognitive workload model may help to explain variations of findings on the relationship of gestational age with cognitive performance in the literature. The findings have implications for routine cognitive follow-up, educational intervention, and basic research into neuro-plasticity and brain reorganization after preterm birth

Algebraic QFT in Curved Spacetime and quasifree Hadamard states: an introduction

Within this chapter (published as [49]) we introduce the overall idea of the algebraic formalism of QFT on a fixed globally hyperbolic spacetime in the framework of unital $*$-algebras. We point out some general features of CCR algebras, such as simplicity and the construction of symmetry-induced homomorphisms. For simplicity, we deal only with a real scalar quantum field. We discuss some known general results in curved spacetime like the existence of quasifree states enjoying symmetries induced from the background, pointing out the relevant original references. We introduce, in particular, the notion of a Hadamard quasifree algebraic quantum state, both in the geometric and microlocal formulation, and the associated notion of Wick polynomials.Comment: v3: better discussion of Unitary Equivalence, thanks to comments of Ko Sanders. v2: minor corrections, added reference to older work by Sahlmann and Verch. v1: 59 pages, 4 figures. arXiv admin note: text overlap with arXiv:1008.1776 by other author

Macroscopic transport by synthetic molecular machines

Nature uses molecular motors and machines in virtually every significant biological process, but demonstrating that simpler artificial structures operating through the same gross mechanisms can be interfaced with—and perform physical tasks in—the macroscopic world represents a significant hurdle for molecular nanotechnology. Here we describe a wholly synthetic molecular system that converts an external energy source (light) into biased brownian motion to transport a macroscopic cargo and do measurable work. The millimetre-scale directional transport of a liquid on a surface is achieved by using the biased brownian motion of stimuli-responsive rotaxanes (‘molecular shuttles’) to expose or conceal fluoroalkane residues and thereby modify surface tension. The collective operation of a monolayer of the molecular shuttles is sufficient to power the movement of a microlitre droplet of diiodomethane up a twelve-degree incline.