On the contribution of the Hall term in small-scale magnetohydrodynamic dynamo

A detailed study of small-scale Hall magnetohydrodynamic dynamo has been performed both analytically and numerically. Assuming the magnetic field and the current to be separate fields, the contribution of the Hall term has been decomposed into two parts and their individual contributions have been studied separately. Calculating the scale-separated transfer rates described in Dar \textit{et. al.} (Physica D, 157 (207), 2001), it is found that the small-scale current fields are the primary contributors in sustaining large scale magnetic fields. Furthermore, the nature of the scale-to-scale fluxes are found to be globally intact with the ion inertial scale

A Three Dimensional Lattice of Ion Traps

We propose an ion trap configuration such that individual traps can be stacked together in a three dimensional simple cubic arrangement. The isolated trap as well as the extended array of ion traps are characterized for different locations in the lattice, illustrating the robustness of the lattice of traps concept. Ease in the addressing of ions at each lattice site, individually or simultaneously, makes this system naturally suitable for a number of experiments. Application of this trap to precision spectroscopy, quantum information processing and the study of few particle interacting system are discussed.Comment: 4 pages, 4 Figures. Fig 1 appears as a composite of 1a, 1b, 1c and 1d. Fig 2 appears as a composite of 2a, 2b and 2

Non-equilibrium quantum magnetism in a dipolar lattice gas

Research on quantum magnetism with ultra-cold gases in optical lattices is expected to open fascinating perspectives for the understanding of fundamental problems in condensed-matter physics. Here we report on the first realization of quantum magnetism using a degenerate dipolar gas in an optical lattice. In contrast to their non-dipolar counterparts, dipolar lattice gases allow for inter-site spin-spin interactions without relying on super-exchange energies, which constitutes a great advantage for the study of spin lattice models. In this paper we show that a chromium gas in a 3D lattice realizes a lattice model resembling the celebrated t-J model, which is characterized by a non-equilibrium spinor dynamics resulting from inter-site Heisenberg-like spin-spin interactions provided by non-local dipole-dipole interactions. Moreover, due to its large spin, chromium lattice gases constitute an excellent environment for the study of quantum magnetism of high-spin systems, as illustrated by the complex spin dynamics observed for doubly-occupied sites.Comment: 10 pages, 5+5 figure

Transverse laser cooling of a thermal atomic beam of dysprosium

A thermal atomic beam of dysprosium (Dy) atoms is cooled using the $4f^{10}6s^2 (J=8) \to 4f^{10}6s6p (J=9)$ transition at 421 nm. The cooling is done via a standing light wave orthogonal to the atomic beam. Efficient transverse cooling to the Doppler limit is demonstrated for all observable isotopes of dysprosium. Branching ratios to metastable states are demonstrated to be $<5\times10^{-4}$. A scheme for enhancement of the nonzero-nuclear-spin-isotope cooling, as well as a method for direct identification of possible trap states, is proposed.Comment: 5 pages, 4 figures v2: 7 pages, 7 figure

Optical control of resonant light transmission for an atom-cavity system

We demonstrate the manipulation of transmitted light through an optical Fabry-Pérot cavity, built around a spectroscopy cell containing enriched rubidium vapor. Light resonant with the 87RbD2 (F=2,F=1) ↔F′ manifold is controlled by the transverse intersection of the cavity mode by another resonant light beam. The cavity transmission can be suppressed or enhanced depending on the coupling of atomic states due to the intersecting beams. The extreme manifestation of the cavity-mode control is the precipitous destruction (negative logic switching) or buildup (positive logic switching) of the transmitted light intensity on intersection of the transverse control beam with the cavity mode. Both the steady-state and transient responses are experimentally investigated. The mechanism behind the change in cavity transmission is discussed in brief

Diagnostic and therapeutic approaches to optic disc pit maculopathy in children

Background: Optic disc pit (ODP) is a rare congenital defect of the optic disc that can lead to maculopathy and gradual visual impairment. This review summarizes our current knowledge on the diagnostic and therapeutic approaches to ODP maculopathy (ODP-M) in children. Methods: A thorough literature search was performed using the PubMed/MEDLINE database from 1960 to 2020. An additional search was conducted using Google Scholar for completeness. Results: ODP-M is characterized by the accumulation of subretinal and/or intraretinal fluid. The exact pathogenetic mechanisms are not fully understood, and the origin of the fluid remains unknown. Although ODP-M is more likely to occur during the third or fourth decade of life, cases of children with serous retinal detachment have been recorded. Early diagnosis of ODP-M and prompt, appropriate management are crucial, particularly in patients of amblyogenic age. In adults, ODP-M may resolve spontaneously, but most cases require surgical intervention to prevent permanent loss of vision. However, the fact that ODP-M may spontaneously resolve in children cannot be ignored. Various surgical methods have been described, including pars plana vitrectomy (PPV) combined with various techniques, including laser photocoagulation, intravitreal gas injection, and macular buckling. Conclusions: PPV remains the mainstay surgical approach for ODP-M. However, ODP-M may differ between children and adults. Children constitute a unique population of patients that require a different and probably more tailor-made approach. Detailed clinical examination, combined with a thorough analysis of retinal imaging, may improve our understanding of the background and pathophysiology of the disease and eventually provide us with new insights into the management of ODP-M in the pediatric population. How to cite this article: Kalogeropoulos D, Asproudis I,&nbsp; Ch’ng SW, Mitra A, Sharma A, Katsikatsos K, Asproudis C, Kalogeropoulos C. Diagnostic and therapeutic approaches to optic disc pit maculopathy in children. Med Hypothesis Discov Innov Optom.2021 Spring; 2(1): 24-35. DOI: https://doi.org/10.51329/mehdioptometry12

Intravitreal Fluocinolone Acetonide (ILUVIEN) Implant for the Treatment of Refractory Cystoid Macular Oedema After Retinal Detachment Repair

Cystoid macular oedema (CMO) is one of the most frequent postoperative macular complications to cause partial visual recovery after successful retinal detachment (RD) repair. Refractory CMO is difficult to treat and many strategies have been employed with varying degrees of success. We report for the first time the use of ILUVIEN implant to treat refractory CMO after successful RD repair. A 65-year-old female presented with right eye full-thickness macular hole and underwent pars plana vitrectomy, internal limiting membrane peeling and cryotherapy with gas tamponade with 12% C3F8. She subsequently developed right eye macula-on RD and proliferative vitreoretinopathy and required multiple procedures for successful retinal reattachment. Later, she developed CMO that responded to intravitreal triamcinolone injections and intravitreal dexamethasone 0.7-mg implants but recurrence of CMO continued to be a problem. After receiving ILUVIEN intravitreal implant, her visual acuity improved and CMO resolved without recurrence for 13 months. Refractory CMO after RD repair is difficult to treat and in a quarter of cases will not improve without treatment. Our case shows that a single ILUVIEN implant maintained anatomical dry fovea and improved vision. This also demonstrates that ILUVIEN is an effective management strategy to reduce the need for repeated treatments