Oxford ion-trap quantum computing project

We describe recent progress in the development of an ion-trap quantum information processor. We discuss the choice of ion species and describe recent experiments on read-out for a ground-state qubit and photoionization trap loading.     

谁要可持续发展——设计中的环境意识

最好的建筑是把建筑的不同角色（如社会的，环境的，结构的，功能的，美学的角色等）积极地结合起来并使它们相互包容。敏感，恰当而巧妙地实现可持续性的最终设计方案，只能经过复杂而交互的过程才能产生，而并不是从一开始就明确地关注于环境方面的规则。本文回顾了剑桥大学一年级环境设计教学的课程，说明了鼓励学生的环境意识是促成可持续性作为一个主要设计元素的关键。     

Invisible city: a Jerusalem in the forest?

The Bielski partisans are perhaps the most famous of the ‘Forest Jews’ of Belarus, Jews who engaged in active resistance to the Germans in the years between 1941 and 1944 from their hide-outs in the forest. When they escaped to ‘partisan country’ Jews had to adjust to an entirely new physical and social environment. Persecuted by one of the most technologically advanced armies in the world, and forced by circumstances to join the Soviet-led, communist, anti-religious partisan movement, the Bielski group faced numerous social and cultural dilemmas in establishing the living conditions that ensured their survival. The extreme cold of the Russian winter made circumstances extremely harsh, ‘living like animals’ according to one partisan, although in time life improved sufficiently for many in the Bielski detachment to believe that their final camp had acquired the status of a small town or shtetl. If, however, such military camps have often recalled more established urban settlements, this question requires clarification in the Bielski case, and is the principal focus of this paper. In its examination of the dwellings and settlements constructed by the Bielski group, and how they evolved over time, the study underlines the minimum dimensions of culture that arise in near-survival conditions.     

Beyond bits: the future of quantum information processing

Today's computers operate on the same fundamental principle as the mechanical devices dreamed up by Charles Babbage in the 19th century and later formalized by Alan Turing: one stable state of the machine represents one number. Even seemingly nonstandard computation models, such as the one based on DNA, share this basic principle. Recently, physicists and computer scientists have realized that not only do their ideas about computing rest on partly accurate principles, but they miss out on a whole class of computation. Quantum physics offers powerful methods of encoding and manipulating information that are not possible within a classical framework. The potential applications of these quantum information processing methods include provably secure key distribution for cryptography, rapid integer factoring, and quantum simulation. The authors discuss the directions that quantum information theory appears to be heading and the research and applications it has accrued