A single-atom quantum memory.

The faithful storage of a quantum bit (qubit) of light is essential for long-distance quantum communication, quantum networking and distributed quantum computing. The required optical quantum memory must be able to receive and recreate the photonic qubit; additionally, it must store an unknown quantum state of light better than any classical device. So far, these two requirements have been met only by ensembles of material particles that store the information in collective excitations.

Critical flicker-fusion frequency in age-related macular degeneration.

Purpose: To assess the influence of age-related macular degeneration (AMD) on critical flicker-fusion frequency (CFF).

Methods: CFF was measured centrally for a red, green and blue target, and in 10 degrees excentricity with a red target. Twenty-eight patients with non-exsudative AMD, 12 patients with exsudative AMD and 45 age-matched healthy eyes were included.

Combination of transepithelial phototherapeutic keratectomy and autologous serum eyedrops for treatment of recurrent corneal erosions.

Purpose: To evaluate the clinical outcomes after transepithelial phototherapeutic keratectomy (t-PTK) using an excimer laser and postoperative administration of autologous serum eyedrops.

Setting: Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Heidelberg, Germany.

Methods: Twenty-five eyes of 25 patients with 3 to 12 recurrent corneal erosions were treated with t-PTK using the Schwind Keratom broad-beam excimer laser (Schwind).