Atom lasers: production, properties and prospects for precision inertial measurement

We review experimental progress on atom lasers out-coupled from Bose-Einstein condensates, and consider the properties of such beams in the context of precision inertial sensing. The atom laser is the matter-wave analog of the optical laser. Both devices rely on Bose-enhanced scattering to produce a macroscopically populated trapped mode that is output-coupled to produce an intense beam. In both cases, the beams often display highly desirable properties such as low divergence, high spectral flux and a simple spatial mode that make them useful in practical applications, as well as the potential to perform measurements at or below the quantum projection noise limit. Both devices display similar second-order correlations that differ from thermal sources. Because of these properties, atom lasers are a promising source for application to precision inertial measurements.Comment: This is a review paper. It contains 40 pages, including references and figure

Degenerative Veränderungen im alternden Innenohr, mit besonderer Berücksichtigung der vasculären Veränderungen, in Flächenpräparaten der menschlichen Cochlea dargestellt

Temporal bones from 150 patients, ranging in age from fetuses and newborn to 97 years, were studied by the technique of microdissection and the use of surface specimens stained with OSO 4 . Hair cell and nerve degeneration were seen in the extreme basal turn of the cochlea even in children. In the fetal cochlea vascularization is very dense, in the newborn and infant somewhat less so. A gradual involution of blood vessels occurs postnatally and continues with maturity and aging. Involution is seen especially in the membranous wall of the cochlea and in the system of spiral vessels of the basilar membrane and vestibular lip. During the first decade the radiating arterioles and the outer spiral vessel in the basal turn are reduced to their adult size. In presbycusis material we observed a marked loss of capillaries and of some of the radiating arterioles in the spiral ligament. Other arterioles had thickened walls. This devascularization was accompanied by atrophy and acellularity of the spiral ligament and atrophy of the stria. Atrophy of the spiral vessels was seen, especially in the lower half of the basal turn. Most of the cochlear blood vessels have clearly distinguishable perivascular spaces. Vessels which had become occluded and disappeared left behind them intervascular strands and/or avascular channels . Such channels were seen to connect the perivascular space of one capillary with that of another, representing the perivascular space of the vessel which had atrophied. The hair cell and nerve degeneration seen in presbycusis may be caused, at least in part, by microangiopathy of this type. Similar vascular changes have been observed in retinal vessels. It is possible that the gradual reduction of blood supply through the disappearance of capillaries occurs in many tissues of the body and plays an important role in the aging process. Mit Hilfe der Oberflächenpräparation wurden von uns 150 menschliche Labyrinthe aller Altersgruppen untersucht. Es wurde eine Haarzellen-und Nervendegeneration schon im Kindesalter beobachtet. Blutgefäße in der Schnecke haben perivasculdre Spalten; Gefäße atrophieren and werden zu „avascular channels”, leeren Spaltrdumen oder Striingen. Bei Presbyakusis fällt neben der Haarzell- and Nervendegeneration in der Basalwindung der Schnecke die Gefäßatrophie im Ligamentum spirale und der Membrana basilaris auf. Dazu kommt noch eine beträchtliche Atrophie des Ligamentum spirale und der Stria vascularis. Bemerkenswert ist, daß die Devascularisation schon im Kindesalter beginnt.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47255/1/405_2004_Article_BF00373313.pd