Coherent photon manipulation in interacting atomic ensembles

Coupling photons to Rydberg excitations in a cold atomic gas yields unprecedentedly large optical nonlinearities at the level of individual light quanta, where the formation of nearby dark-state polaritons is blocked by the strong interactions between Rydberg atoms. This blockade mechanism, however, realizes an inherently dissipative nonlinearity, which limits the performance of practical applications. In this work, we propose a new approach to strong photon interactions via a largely coherent mechanism at drastically suppressed photon losses. Rather than a polariton blockade, it is based on an interaction induced conversion between distinct types of dark-state polaritons with different propagation characteristics. We outline a specific implementation of this approach and show that it permits to turn a single photon into an effective mirror with a robust and continuously tuneable reflection phase. We describe potential applications, including a detailed discussion of achievable operational fidelities

Certain aspects of the breeding biology of the kittiwake (rissa tridactyla)

Data on aspects of the breeding biology of a colony of Kittiwakes in North East England, in which all breeding adults are individually colour-marked, have been collected annually since 1954. The inter-relationships between different factors have been investigated and year-to-year changes in the breeding biology of the colony, related to changes in population structure. Date of return to the colony is shown to be primarily determined by age. Synchrony of return between the members of a breeding pair is associated with the maintenance of the pair bond. Other factors influencing the duration of the pair bond are investigated, including the prior association between the members of the pair, breeding success in the previous year and mortality rates in different years. As birds get older, the main cause of the break-up of the pair bond changes from 'divorce' to bereavement. Time of breeding is related to the location of the nest site (centre or edge of the colony) and the breeding experience of the two members of the pair. There is a tendency for breeding to become more synchronised amongst older age groups, with females laying progressively closer to the mean date of laying for the colony as a whole. The possible interactions between environmental cues, stimulus from the mate and stimulus from the rest of the colony are discussed. Clutch size is shown to be independently influenced by breeding experience, date of laying, location of the nest site and the status of the pair (retention of the same mate as in the previous year, or change). Variations in the size and shape of eggs laid by different females are investigated with respect to many of the above factors

Study of space battery accelerated testing techniques. Phase 1 report. Survey of testing methods applicable to space battery evaluation

Testing methods applicable to space battery evaluation - literature surve

Religion in Scots Law: Report of an Audit at the University of Glasgow

No abstract available

Religion in Scots Law: Report of an Audit at the University of Glasgow

No abstract available

Study of space battery accelerated testing techniques. Phase 2 report - Ideal approaches towards accelerated tests and analysis of data

Ideal approaches to accelerated life tests and data analysis applied to space batterie

Photon Subtraction by Many-Body Decoherence

We experimentally and theoretically investigate the scattering of a photonic quantum field from another stored in a strongly interacting atomic Rydberg ensemble. Considering the many-body limit of this problem, we derive an exact solution to the scattering-induced spatial decoherence of multiple stored photons, allowing for a rigorous understanding of the underlying dissipative quantum dynamics. Combined with our experiments, this analysis reveals a correlated coherence-protection process in which the scattering from one excitation can shield all others from spatial decoherence. We discuss how this effect can be used to manipulate light at the quantum level, providing a robust mechanism for single-photon subtraction, and experimentally demonstrate this capability