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"Helium Cryogenics, 2nd edition brings these advances in helium cryogenics together in an updated form. As in the original edition, the author's approach is to survey the field of cryogenics with emphasis on helium fluids. This approach is more specialized and fundamental than that contained in other cryogenics books, which treat the associated range of cryogenic fluids. As a result, the level of treatment is more advanced and assumes a certain knowledge of fundamental engineering and physics principles, including some quantum mechanics. The goal throughout the work is to bridge the gap between the physics and engineering aspects of helium fluids to provide a source for engineers and scientists to enhance their usefulness in low-temperature systems."

"This thesis presents an experimental and theoretical study of the coherent properties of trapped atomic ensembles at high densities, which are essential to many of the aforementioned applications. The study focuses on how inter-particle interactions modify the ensemble coherence dynamics, and whether it is possible to extend the coherence time by means of external control. The thesis presents a theoretical model which explains the effect of elastic collision of the coherence dynamics and then reports on experiments which test this model successfully in the lab. Furthermore, the work includes the first implementation of dynamical decoupling with ultra-cold atomic ensembles. It is demonstrated experimentally that by using dynamical decoupling the coherence time can be extended 20-fold. This has a great potential to increase the usefulness of these ensembles for quantum computation."