Enhanced quantum interface with collective ion-cavity coupling.

We prepare a maximally entangled state of two ions and couple both ions to the mode of an optical cavity. The phase of the entangled state determines the collective interaction of the ions with the cavity mode, that is, whether the emission of a single photon into the cavity is suppressed or enhanced. By adjusting this phase, we tune the ion-cavity system from sub- to superradiance. We then encode a single qubit in the two-ion superradiant state and show that this encoding enhances the transfer of quantum information onto a photon.

[Applications of optical coherence tomography (OCT) in neuro-ophthalmology]. / Anwendungsgebiete für die Optische Kohärenztomografie (OCT) in der Neuroophthalmologie.

Optical coherence tomography (OCT) has revolutionised ophthalmology. Due to modern instruments with extremely high resolution there are more and more applications also in neuro-ophthalmological disorders. This review gives an overview on typical changes in OCT for the following diseases: autosomal dominant optic atrophy, Leber hereditary optic neuropathy, toxic, traumatic and compressive optic neuropathy, optic nerve drusen, anterior ischaemic optic neuropathy, optic disc pit, papilledema, optic neuritis (isolated or associated with multiple sclerosis or neuromyelitis optica), neurodegenerative diseases and hereditary retinal diseases. A diagnosis exclusively based on an OCT examination is not always possible, but in several diseases there are pathognomonic changes that directly lead to the correct diagnosis. Particularly with the often complex settings in neuro-ophtalmology the OCT should be seen as a supplementary modality and not as a replacement for other techniques.

Quantum-state transfer from an ion to a photon.

One model for quantum networks1,2 is based on the probabilistic measurement of two photons, each entangled with a distant node, e.g., an atom or atomic ensemble3-7. A second, deterministic model transfers information directly from an atom onto a cavity photon, which carries it to a second node8, as recently demonstrated with neutral atoms9. In both cases, the challenge is to transfer information efficiently while preserving coherence. Here, following the second scheme, we map the quantum state of an ion onto a photon within an optical cavity. Using an ion enables deterministic state initialization10,11, while the cavity provides coherent coupling to a well-defined output mode12-15. Although it is often assumed that a cavity-based quantum interface requires the strong-coupling regime, we show transfer fidelities of 92% in the presence of non-negligible decoherence and characterize the interplay between fidelity and efficiency. Our time-independent mapping process offers a promising route toward ion-based quantum networks.

Integrated fiber-mirror ion trap for strong ion-cavity coupling.

We present and characterize fiber mirrors and a miniaturized ion-trap design developed to integrate a fiber-based Fabry-Perot cavity (FFPC) with a linear Paul trap for use in cavity-QED experiments with trapped ions. Our fiber-mirror fabrication process not only enables the construction of FFPCs with small mode volumes, but also allows us to minimize the influence of the dielectric fiber mirrors on the trapped-ion pseudopotential. We discuss the effect of clipping losses for long FFPCs and the effect of angular and lateral displacements on the coupling efficiencies between cavity and fiber. Optical profilometry allows us to determine the radii of curvature and ellipticities of the fiber mirrors. From finesse measurements, we infer a single-atom cooperativity of up to 12 for FFPCs longer than 200 µm in length; comparison to cavities constructed with reference substrate mirrors produced in the same coating run indicates that our FFPCs have similar scattering losses. We characterize the birefringence of our fiber mirrors, finding that careful fiber-mirror selection enables us to construct FFPCs with degenerate polarization modes. As FFPCs are novel devices, we describe procedures developed for handling, aligning, and cleaning them. We discuss experiments to anneal fiber mirrors and explore the influence of the atmosphere under which annealing occurs on coating losses, finding that annealing under vacuum increases the losses for our reference substrate mirrors. X-ray photoelectron spectroscopy measurements indicate that these losses may be attributable to oxygen depletion in the mirror coating. Special design considerations enable us to introduce a FFPC into a trapped ion setup. Our unique linear Paul trap design provides clearance for such a cavity and is miniaturized to shield trapped ions from the dielectric fiber mirrors. We numerically calculate the trap potential in the absence of fibers. In the experiment additional electrodes can be used to compensate distortions of the potential due to the fibers. Home-built fiber feedthroughs connect the FFPC to external optics, and an integrated nanopositioning system affords the possibility of retracting or realigning the cavity without breaking vacuum.

Heralded entanglement of two ions in an optical cavity.

We demonstrate precise control of the coupling of each of two trapped ions to the mode of an optical resonator. When both ions are coupled with near-maximum strength, we generate ion-ion entanglement heralded by the detection of two orthogonally polarized cavity photons. The entanglement fidelity with respect to the Bell state Ψ+ reaches F≥(91.9±2.5)%. This result represents an important step toward distributed quantum computing with cavities linking remote atom-based registers.

Levels of interleukin-6 and interleukin-8 in seminal fluid of men attending an andrological clinic.

The presence of interleukins (IL) and other cytokines in seminal plasma was demonstrated in the literature. In particular, the levels of IL-6 were found to be related to male accessory gland inflammation. The close correlation to leucocyte count indicates a production of interleukins from the leucocytes and by the prostate gland. No relation of IL-6 levels to spermatogenic activity was quoted in the literature. We measured IL-6 and IL-8 in 454 men and compared the values with seminal parameters. The mean values of IL-6 30.7 +/- 101.2 pg ml-1 and IL-8 2023 +/- 1721 pg ml-1. The correlation analysis revealed a significant correlation of IL-6 and/or IL-8 to age, total fructose, immunoglobulin G (IgG) concentration and leucocyte count. The significant correlation of IL-6 and fructose levels indicates that also the seminal vesicles take part in the production of seminal IL-6. No correlation of the two interleukins measured to sperm parameters occurred. The calculation of a single harmonic trend revealed a significant trend over the year of the levels of IL-6 with a maximum in December and a peak-to-trough variation of 33% of the mean. It may be the consequence of a higher frequency of seminal tract inflammations in autumn and winter.

Effects of skin occlusion in patch testing with sodium lauryl sulphate.

BACKGROUND: When evaluating transepidermal water loss (TEWL) in patch testing, the occlusive effect of the patch must be considered as an important artificial impairment of the measurement. OBJECTIVES: To investigate the time course of effects of occlusion. METHODS: Epicutaneous patches with sodium lauryl sulphate (SLS) 0.25%, SLS 0.5%, water and an empty test chamber (control) were applied on the volar forearm for different time intervals (12, 24, 48 h). Test reactions were evaluated by measurement of TEWL immediately, every 15 min during the first hour, every 30 min during the following 3 h and 24 h after patch removal. RESULTS: After patch removal, TEWL values showed a steep increase. When compared with basal values, TEWL values after SLS patch testing remained increased for 24 h, whereas TEWL values on water patch sites were only significantly increased for up to 180 min, and on empty patch sites for only up to 120 min after patch removal. The prolonged increase in TEWL values in SLS patch testing seemed to be induced by barrier function damage caused by SLS itself, as shown in various earlier studies. After the initial increase, TEWL values showed a significant decrease for all patches from 0 to 120 min after patch removal. Patch testing with water gave a significant decrease in TEWL values up to 180 min, and for empty chambers (control) up to 150 min after removal of patches. These data suggest that the occlusive effect on TEWL in patch testing ends 3 h after the removal of test chambers. CONCLUSIONS: We recommend TEWL measurement in SLS patch testing after a period of at least 3 h after patch removal. For practical purposes a 24-h period after patch removal may be useful.

Changes in skin physiology during bath PUVA therapy.

BACKGROUND: Frequent bathing leads to a skin barrier damage with various changes in physiological skin parameters. Conversely, ultraviolet (UV) irradiation may improve the impaired skin barrier by reducing inflammatory reactions. OBJECTIVES: The aim of this study was to investigate the changes of physiological skin parameters during a therapy with 8-methoxypsoralen (8-MOP) bathing and subsequent UVA irradiation. METHODS: Thirty patients with a skin disease without barrier disruption were treated with daily bathing in a 8-MOP solution (0.0005%) and subsequent UVA irradiation. Multiple physiological skin parameters (transepidermal water loss, skin blood flow, skin colour, sebum content, skin hydration) were measured repeatedly on clinically non-affected skin on the back, forearm and forehead. In addition, patch testing with sodium lauryl sulphate (SLS) (0.5%) was performed on the forearm and on the back. RESULTS: We found a moderate but significant disturbance of skin barrier and hydration on the forearm and the back (bathing + irradiation) after increasing dosages of therapy. In addition, SLS testing leads to stronger reactions. CONCLUSIONS: We conclude that on clinically healthy skin the impairment of skin barrier by frequent bathing cannot be completely compensated by subsequent UVA irradiation. When conducting a treatment with 8-MOP bathing and UVA irradiation a concomitant therapy supporting the recovery of skin barrier, e.g. with moisturizer, should be performed.