Several comments added, in particular regarding the role of a "second" quantization and concerning some recently proposed cosmological models. -- 21 pages, Latex
发表信息：
Science and Ultimate Reality, J.D. Barrow, P.C.W. Davies, and C.L. Harper Jr., edts. (Cambridge University Press, 2004), pp. 103-120
Schroedinger's wave function shows many aspects of a state of incomplete knowledge or information ("bit"): (1) it is usually defined on a space of classical configurations, (2) its generic entanglement is, therefore, analogous to statistical correlations, and (3) it determines probabilities of measurement outcomes. Nonetheless, quantum superpositions (such as represented by a wave function) define individual physical states ("it"). This conceptual dilemma may have its origin in the conventional operational foundation of physical concepts, successful in classical physics, but inappropriate in quantum theory because of the existence of mutually exclusive operations (used for the definition of concepts). In contrast, a hypothetical realism, based on concepts that are justified only by their universal and consistent applicability, favors the wave function as a description of (thus nonlocal) physical reality. The (conceptually local) classical world then appears as an illusion, facilitated by the phenomenon of decoherence, which is consistently explained by the very entanglement that must dynamically arise in a universal wave function.
Coupling a single atomic quantum bit to a high finesse optical cavity
四极S $_{1/2}$ - D $_{5/2}$光学跃迁的一个单一的捕获的钙$^+$离子，非常适合于编码量子比特的信息，相干耦合到驻波场的高精细度腔。通过观察离子对腔内场的空间和时间变化的响应来验证耦合。我们还实现了确定性的耦合腔模式的离子的振动状态，通过选择性地激发振动状态变化的过渡，并通过控制离子的位置，在驻波领域与纳米精度。
Non-Interactive Statistically-Hiding Quantum Bit Commitment from Any Quantum One-Way Function
本文提出了一种非交互式的量子比特承诺方案，该方案对任何量子单向函数都具有隐藏性和计算绑定性。我们的协议基本上是以前的非交互式量子比特承诺计划（基于量子单向排列，由于Dumais，Mayer和Salvail（EUROWALPT 2000））与成对独立的散列函数的并行组合。为了从任意量子单向函数构造非交互量子比特承诺方案，我们遵循以下步骤：（i）从Dumais-Mayer-Salvail方案到弱隐藏和二选一绑定承诺（ii）从弱隐藏和2选1绑定承诺到强隐藏和2选1绑定承诺;（iii）从强隐藏和二选一约束承诺到正常隐藏承诺。在经典的情况下，可以使用自动隐藏比特承诺方案（Haitner，Nguyen，Ong，Reingold和Vadhan（SIAM J. Comput.，Vol.39，2009））也可以从任何单向函数构造。虽然经典的隐藏比特承诺具有较大的轮复杂度，但我们的量子方案是非交互的，这比经典方案更有优势。一个主要的技术贡献是提供了一个量子模拟的新的互动哈希定理，由于海特纳和Reingold（CCC 2007）。此外，并行组合使我们能够大大简化安全分析。
