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

Perfect imaging with positive refraction in three dimensions

Maxwell's fish eye has been known to be a perfect lens within the validity range of ray optics since 1854. Solving Maxwell's equations we show that the fish-eye lens in three dimensions has unlimited resolution for electromagnetic waves

Lipkin's conservation law, Noether's theorem, and the relation to optical helicity

Copyright © 2013 American Physical SocietyA simple conserved quantity for electromagnetic fields in vacuum was discovered by Lipkin in 1964. In recent years this "zilch" has been used as a measure of the chirality of light. The conservation of optical zilch is here derived from a simple symmetry of the standard electromagnetic action. The symmetry transformation allows the identification of circularly polarized plane waves as zilch eigenstates. The same symmetry is present for electromagnetism in a homogeneous, dispersive medium, allowing the derivation of the zilch density and flux in such a medium. Optical helicity density and flux are also derived for a homogeneous, dispersive medium. For monochromatic beams in vacuum, optical zilch is proportional to optical helicity. This monochromatic zilch-helicity relation acquires a factor of the square of the phase index in a dispersive medium

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

General Relativity in Electrical Engineering

In electrical engineering metamaterials have been developed that offer unprecedented control over electromagnetic fields. Here we show that general relativity lends the theoretical tools for designing devices made of such versatile materials. Given a desired device function, the theory describes the electromagnetic properties that turn this function into fact. We consider media that facilitate space-time transformations and include negative refraction. Our theory unifies the concepts operating behind the scenes of perfect invisibility devices, perfect lenses, the optical Aharonov-Bohm effect and electromagnetic analogs of the event horizon, and may lead to further applications

Gyroscope precession in cylindrically symmetric spacetimes

We present calculations of gyroscope precession in spacetimes described by Levi-Civita and Lewis metrics, under different circumstances. By doing so we are able to establish a link between the parameters of the metrics and observable quantities, providing thereby a physical interpretation for those parameters, without specifying the source of the field.Comment: 13 pages, Latex. To appear in Class.Q.Gra

Transitioning HIV-infected adolescents to adult care at 14 clinics across the United States: Using adolescent and adult providers’ insights to create multi-level solutions to address transition barriers

HIV-infected adolescents have disproportionately low rates of care retention and viral suppression. Approximately half disengage from care while transitioning to adult clinics, in part due to fragmented care systems and lack of streamlined protocols. We conducted 58 qualitative interviews with social service and health care providers across 14 Adolescent Trials Network clinics (n=28) and 20 adult clinics that receive transitioning adolescents (n=30) from August 2015 – June 2016. We used the constant comparative approach to examine processes, barriers, and facilitators of adult care transition. Transition barriers coalesced around three levels. Structural: insurance eligibility, transportation, and HIV-related stigma; Clinical: inter-clinic communication, differences in care cultures, and resource/personnel limitations; and Individual: adolescents’ transition readiness and developmental capacity. Staff-initiated solutions (e.g., grant-funded transportation) were often unsustainable and applied individual-level solutions to structural-level barriers. Comprehensive initiatives, which develop collaborative policies and protocols that support providers’ ability to match the solution and barrier level (i.e., structural-to-structural), are sorely needed. These initiatives should also support local systematic planning to facilitate inter-clinic structures and communication. Such approaches will help HIV-infected adolescents transition to adult care and improve long-term health outcomes

Divergence of Casimir stress in inhomogeneous media

Copyright © 2013 American Physical SocietyWe examine the local behavior of the regularized stress tensor commonly used in calculations of the Casimir force for a dielectric medium inhomogeneous in one direction. It is shown that the usual expression for the stress tensor is not finite anywhere within the medium, whatever the temporal dispersion or index profile, and that this divergence is unlikely to be removed through a simple modification to the regularization procedure. Our analytic argument is illustrated numerically for a medium approximated as a series of homogeneous strips, as the width of these strips is taken to zero. The findings hold for all magnetodielectric media

On parameters of the Levi-Civita solution

The Levi-Civita (LC) solution is matched to a cylindrical shell of an anisotropic fluid. The fluid satisfies the energy conditions when the mass parameter $\sigma$ is in the range $0 \le \sigma \le 1$. The mass per unit length of the shell is given explicitly in terms of $\sigma$, which has a finite maximum. The relevance of the results to the non-existence of horizons in the LC solution and to gauge cosmic strings is pointed out.Comment: Latex, no figure