Evaluation of the effects of space environment exposure on index of refraction and extinction coefficients of Apollo window materials

Temperature and radiation effects on index of refraction and extinction coefficients of Apollo window material

Comment on "Quantum Friction - Fact or Fiction?"

If quantum friction existed [J.B. Pendry, New J. Phys. 12, 033028 (2010)] an unlimited amount of useful energy could be extracted from the quantum vacuum and Lifshitz theory would fail. Both are unlikely to be true.Comment: Comment on J.B. Pendry, New J. Phys. 12, 033028 (2010

Casimir effect from macroscopic quantum electrodynamics

The canonical quantization of macroscopic electromagnetism was recently presented in New J. Phys. 12 (2010) 123008. This theory is here used to derive the Casimir effect, by considering the special case of thermal and zero-point fields. The stress-energy-momentum tensor of the canonical theory follows from Noether's theorem, and its electromagnetic part in thermal equilibrium gives the Casimir energy density and stress tensor. The results hold for arbitrary inhomogeneous magnetodielectrics and are obtained from a rigorous quantization of electromagnetism in dispersive, dissipative media. Continuing doubts about the status of the standard Lifshitz theory as a proper quantum treatment of Casimir forces do not apply to the derivation given here. Moreover, the correct expressions for the Casimir energy density and stress tensor inside media follow automatically from the simple restriction to thermal equilibrium, without the need for complicated thermodynamical or mechanical arguments.Comment: Minor corrections. 21 pages. To appear in New J. Phy

Canonical quantization of macroscopic electromagnetism

Application of the standard canonical quantization rules of quantum field theory to macroscopic electromagnetism has encountered obstacles due to material dispersion and absorption. This has led to a phenomenological approach to macroscopic quantum electrodynamics where no canonical formulation is attempted. In this paper macroscopic electromagnetism is canonically quantized. The results apply to any linear, inhomogeneous, magnetodielectric medium with dielectric functions that obey the Kramers-Kronig relations. The prescriptions of the phenomenological approach are derived from the canonical theory.Comment: 21 pages, additional reference

Molecular van der Waals fluids in cavity quantum electrodynamics

Intermolecular van der Waals interactions are central to chemical and physical phenomena ranging from biomolecule binding to soft-matter phase transitions. However, there are currently very limited approaches to manipulate van der Waals interactions. In this work, we demonstrate that strong light-matter coupling can be used to tune van der Waals interactions, and, thus, control the thermodynamic properties of many-molecule systems. Our analysis reveals orientation-dependent intermolecular interactions between van der Waals molecules (for example, H2) that depend on the distance between the molecules R as R−3 and R0. Moreover, we employ non-perturbative \textit{ab initio} cavity quantum electrodynamics calculations to develop machine learning-based van der Waals interaction potentials for molecules inside optical cavities. By simulating fluids of up to 1,000 H2 molecules, we demonstrate that strong light-matter coupling can tune the structural and thermodynamic properties of molecular fluids. In particular, we observe collective orientational order in many-molecule systems as a result of cavity-modified van der Waals interactions. These simulations and analyses demonstrate both local and collective effects induced by strong light-matter coupling and open new paths for controlling the properties of condensed phase systems

Understanding Care Linkage and Engagement Across 15 Adolescent Clinics: Provider Perspectives and Implications for Newly HIV-Infected Youth

The National HIV/AIDS Strategy emphasizes rapid care linkage and engagement for HIV-infected individuals, though many adolescents are never tested, delay entering care, and frequently drop out. We conducted 183 staff interviews at 15 adolescent medicine clinics (baseline, n = 64; Year 1, n = 60; Year 2, = 59). We used a constant comparative thematic method to examine how providers approached and discussed care linkage/engagement. Qualitative analyses revealed differences in providers' conceptualizations of linkage and engagement. Providers saw linkage as mechanistic and health system driven. It was defined by number of clinic visits and involved relatively little youth agency. In contrast, providers defined engagement by youths' responsibility and participation in their own care. Linkage and engagement are related but distinct aspects of care that require different resources and levels of staff involvement. Integrating an understanding of these differences into future interventions will allow clinic staff to help youth improve long-term health outcomes

Cylindrical spacetimes with a cosmological constant and their sources

We review and investigate some basic properties of static, cylindrically symmetric spacetimes with non-zero cosmological constant, find non-singular sheet sources of these spacetimes and discuss their characteristics, and clarify their relation to the 4D black-string solutions.Comment: 15 pages, 2 figure

Canonical quantization of electromagnetism in spatially dispersive media

Copyright © 2014 IOP PublishingOpen Access JournalWe find the action that describes the electromagnetic field in a spatially dispersive, homogeneous medium. This theory is quantized and the Hamiltonian is diagonalized in terms of a continuum of normal modes. It is found that the introduction of nonlocal response in the medium automatically regulates some previously divergent results, and we calculate a finite value for the intensity of the electromagnetic field at a fixed frequency within a homogeneous medium. To conclude we discuss the potential importance of spatial dispersion in taming the divergences that arise in calculations of Casimir-type effects.EPSR

Factors affecting linkage to care and engagement in care for newly diagnosed HIV-positive adolescents within fifteen adolescent medicine clinics in the United States

Early linkage to care and engagement in care are critical for initiation of medical interventions. However, over 50 % of newly diagnosed persons do not receive HIV-related care within 6 months of diagnosis. We evaluated a linkage to care and engagement in care initiative for HIV-positive adolescents in 15 U.S.-based clinics. Structural and client-level factors (e.g. demographic and behavioral characteristics, clinic staff and location) were evaluated as predictors of successful linkage and engagement. Within 32 months, 1,172/1,679 (69.8 %) of adolescents were linked to care of which 1,043/1,172 (89 %) were engaged in care. Only 62.1 % (1,043/1,679) of adolescents were linked and engaged in care. Linkage to care failure was attributed to adolescent, provider, and clinic-specific factors. Many adolescents provided incomplete data during the linkage process or failed to attend appointments, both associated with failure to linkage to care. Additional improvements in HIV care will require creative approaches to coordinated data sharing, as well as continued outreach services to support newly diagnosed adolescents

HIV Testing, Care Referral, and Linkage to Care Intervals Affect Time to Engagement in Care for Newly Diagnosed HIV-Infected Adolescents in 15 Adolescent Medicine Clinics in the United States

OBJECTIVE: To examine how the time from HIV testing to care referral and from referral to care linkage influenced time to care engagement for newly diagnosed HIV-infected adolescents. METHODS: We evaluated the Care Initiative, a care linkage and engagement program for HIV-infected adolescents in 15 US clinics. We analyzed client-level factors, provider type, and intervals from HIV testing to care referral and from referral to care linkage as predictors of care engagement. Engagement was defined as a second HIV-related medical visit within 16 weeks of initial HIV-related medical visit (linkage). RESULTS: At 32 months, 2143 youth had been referred. Of these, 866 were linked to care through the Care Initiative within 42 days and thus eligible for study inclusion. Of the linked youth, 90.8% were ultimately engaged in care. Time from HIV testing to referral (eg, ≤7 days versus >365 days) was associated with engagement [adjusted odds ratio = 2.91; 95% confidence interval (CI): 1.43 to 5.94] and shorter time to engagement (adjusted hazard ratio = 1.41; 95% CI: 1.11 to 1.79). Individuals with shorter care referral to linkage intervals (eg, ≤7 days versus 22-42 days) engaged in care faster (adjusted hazard ratio = 2.90; 95% CI: 2.34 to 3.60) and more successfully (adjusted odds ratio = 2.01; 95% CI: 1.04 to 3.89). CONCLUSIONS: These data address a critical piece of the care continuum and can offer suggestions of where and with whom to intervene to best achieve the care engagement goals outlined in the US National HIV/AIDS Strategy. These results may also inform programs and policies that set concrete milestones and strategies for optimal care linkage timing for newly diagnosed adolescents