The plan that failed : the United Nations development decade, and beyond

Development planners are sometimes accused of having too much confidence in their own activities and plans. The economic planner in particular is - even in the eyes of some 6f his fellow developers - a somewhat suspect individual, who has fallen in love with the techniques of quantitative economic analysis and policy making, who has been blinded to the intangible but profound differences in socio-cultural and political environment by his predilection for quantifiable economic relationships - a man, in short, who talks so often and so loudly about his equations and parameters, his ratios, percentages, and GNP estimates, that scientific modesty or a sense of inadequacy seem to be alien to his thinking and behaviour. I am sure that I will not surprise the audience when I say that to me the above picture is a caricature rather than a portrait of the economic planner. As always is the case with ~ caricature, there is some truth in it - though not necessarily much. However that may be, this is not the proper occasion to discuss-this point further, for the simple reason that an inaugural address is a monologue in its very nature. Perhaps I can weaken the impression that development planners behave as if they knew the answers to all questions by choosing as the starting point of my short expose a plan, a set of policy proposals, that is not going to be realized. Therefore, I should like to ask your attention for the Plan that failed. The plan concerned is formed by the proposals for action formulated and accepted by the United Nations at the beginning of the Development Decade

Active SU(1,1) atom interferometry

Active interferometers use amplifying elements for beam splitting and recombination. We experimentally implement such a device by using spin exchange in a Bose-Einstein condensate. The two interferometry modes are initially empty spin states that get spontaneously populated in the process of parametric amplification. This nonlinear mechanism scatters atoms into both modes in a pairwise fashion and generates a nonclassical state. Finally, a matched second period of spin exchange is performed that nonlinearly amplifies the output signal and maps the phase onto readily detectable first moments. Depending on the accumulated phase this nonlinear readout can reverse the initial dynamics and deamplify the entangled state back to empty spin states. This sequence is described in the framework of SU(1,1) mode transformations and compared to the SU(2) angular momentum description of passive interferometers.Comment: 10 pages, 6 figures; invited article for Quantum Science and Technolog