精密测量中的量子极限

给定一个物理装置,对于一个物理可观察量能够得到的测量精度是什么?为了回答这一问题,本文以最近量子精密测量的发展为主线,量子参数估值方法为核心,介绍单粒子(线性耦合)体系和多粒子(非线性耦合)体系物理量测量精度的量子限制.作为例子,对光学量子精密测量中如何突破标准量子极限,甚至海森堡极限做了简明阐述.特别总结了非线性精密测量在突破海森堡极限方面的最新进展.最后,探讨了量子精密测量未来发展的可能趋势.     

Algebraic formulae for the Moon,Saturn and Jupiter in the Pancasiddhantika

Summary The daily motion of the Moon, and the synodic arcs and periods of Saturn and Jupiter are derived from the algebraic formulae given in the Pancasiddhantika.     

Logic of discovery and justification in regulatory genetics

In the above pages I have sketched a history of the genesis and comparative evaluation of the repressor model of genetic regulation of enzyme induction. I have not attempted in this article to carry out an analysis of the more scientifically interesting fully developed Jacob-Monod operon theory of genetic regulations but such an analysis of the operon theory would not, I believe, involve any additional logical or epistemological features than have been discussed above.I have argued that the above account of the development of a theory of enzyme induction involved inferential moves and well-characterized desiderata, of both empirical and non-empirical character, in the genesis and evaluation of new hypotheses and theories. I have also contended that the reasoning displayed in the genesis of a theory is in a large measure identical to that utilized in evaluating a theory. Both of these conclusions are at variance with the views of philosophers such as H. Reichenbach, Sir Karl Popper, and C.G. Hempel who have argued that the genesis of new hypotheses is primarily an irrational affair and that only the context of justification is susceptible of rational reconstruction. In the alternative view presented here, scientific discovery and scientific justification represent the application in contexts, which are primarily telically distinguishable, of a fundamentally unitary logic of scientific inquiry.     

The Early Development of the Algebraic Theory of Semigroups

In the history of mathematics, the algebraic theory of semigroups is a relative new-comer, with the theory proper developing only in the second half of the twentieth century. Before this, however, much groundwork was laid by researchers arriving at the study of semigroups from the directions of both group and ring theory. In this paper, we will trace some major strands in the early development of the algebraic theory of semigroups. We will begin with the aspects of the theory which were directly inspired by, and were analogous to, existing results for both groups and rings, before moving on to consider the first independent theorems on semigroups: theorems with no group or ring analogues. Dedicated to the memory of Professor W. Douglas Munn. This article was begun when the author was an EPSRC-funded research student at the University of York, UK, and completed at CAUL under FCT post-doctoral research grant SFRH/BPD/34698/2007.     

非线性量子力学的建立

笔者在长期研究工作的基础上,从提出非线性量子力学的基本原理出发,建立起了非线性量子力学理论,形成了完整的非线性量子力学的理论体系。从而把量子力学从线性领域推广和发展到非线性领域。在本文中笔者描述了建立这个非线性量子力学的物理背景,它的基本构思,研究的技术路线,产生的实际效果,与国际同类研究比较,本研究的创新和特点以及研究的重大意义。     

量子关联及其应用

量子关联是量子系统具有的一种重要的非经典性质,被普遍研究的量子纠缠就是量子信息处理中重要的量子关联.随着研究的深入,最近发现了很多不需要纠缠的非经典现象在量子信息中扮演了关键角色.文章介绍了基于量子失协及其相关的非经典量子关联,讨论了各种量子关联在量子信息模型中各种物理解释与应用.     

Quantum gravity: Meaning and measurement

A discussion of the meaning of a physical concept cannot be separated from discussion of the conditions for its ideal measurement. We assert that quantization is no more than the invocation of the quantum of action in the explanation of some process or phenomenon, and does not imply an assertion of the fundamental nature of such a process. This leads to an ecumenical approach to the problem of quantization of the gravitational field. There can be many valid approaches, each of which should be judged by the domain of its applicability to various phenomena. If two approaches have overlapping domains, the relation between them then itself becomes a subject of study. We advocate an approach to general relativity based on the unimodular group, which emphasizes the physical significance and measurability of the conformal and projective structures. A discussion of the method of matched asymptotic expansions, and of the weakness of terrestrial sources compared with astrophysical and cosmological sources, leads us to suggest theoretical studies of gravitational radiation based on retrodiction (observation) rather than prediction (experimentation).     

基于DNA分子的逻辑门与计算机

本文对基于DNA分子的逻辑门与计算机研究进行了综述。DNA逻辑门与DNA计算机是目前非常活跃的研究领域,有可能解决电子计算机发展的瓶颈问题。本文从DNA逻辑门的分子基础、DNA逻辑门和DNA计算机等几个方面进行了介绍,并且对可能的发展方向作了一些预期。     

基于模糊逻辑的移动机器人沿墙行为精准控制

针对移动机器人自身的非线性和环境噪声的不确定性,设计了一个基于虹外传感嚣的模糊控制器,并在实验环境中采用多项式拟合方法对红外传感器进行了校正,得到了传感器的校正模型,提高了移动机器入在室内环境中沿墙导航的精度。基于KHEPERA II移动机器人的实验结果表明,校正后的移动机器人在沿墙导航过程中其宥更好的稳定性和鲁棒性,以及更高的效率。     

The Metaphysical Challenge of Loop Quantum Gravity

Many consider the apparent disappearance of time and change in quantum gravity the main metaphysical challenge since it seems to lead to a form of Parmenidean view according to which the physical world simply is, nothing changes, moves, becomes, happens. In this paper, I argue that the main metaphysical challenge of Rovelli’s philosophical view of loop quantum gravity is to lead exactly to the opposite view, namely, a form of Heraclitean view, or rather, of radical process metaphysics according to which there is becoming (process, change, event) but not being (substance, stasis, thing). However, this does not entail that time is real. Fundamentally, time does not exist. I show how Rovelli’s understanding of loop quantum gravity supports the view that there is change without time, so that the physical world can be timeless yet ever-changing. I conclude by arguing that it is such a process-oriented conception that constitutes the revolutionary metaphysical challenge and philosophical significance of loop quantum gravity, while the alleged Parmenidean view turns out to be nothing but the endpoint of a long-standing metaphysical orthodoxy.     

基于二氧化硅的量子点荧光纳米颗粒制备

多步制备了Si02-CdTe QDs荧光纳米颗粒,包括表面氨基化SiO2纳米颗粒载体、组装于载体表面的CdTeQDs壳以及最外层的二氧化硅壳。制备的SiO2-CdTe QDs荧光纳米颗粒性能稳定,紫外吸收和荧光发射增强明显。最外层的SiO2壳保证量子点的化学和光学稳定性的同时,还有助于表面生物基团的修饰。可以预见,SiO2-CdTe QDs荧光纳米颗粒作为生物探针将来应用于生化分析研究的广阔前景。     

Quantum reality: A pragmaticized neo-Kantian approach

Despite remarkable efforts, it remains notoriously difficult to equip quantum theory with a coherent ontology. Hence, Healey (2017, 12) has recently suggested that “quantum theory has no physical ontology and states no facts about physical objects or events”, and Fuchs et al. (2014, 752) similarly hold that “quantum mechanics itself does not deal directly with the objective world”. While intriguing, these positions either raise the question of how talk of ‘physical reality’ can even remain meaningful, or they must ultimately embrace a hidden variables-view, in tension with their original project. I here offer a neo-Kantian alternative. In particular, I will show how constitutive elements in the sense of Reichenbach (1920) and Friedman (1999, 2001) can be identified within quantum theory, through considerations of symmetries that allow the constitution of a ‘quantum reality’, without invoking any notion of a radically mind-independent reality. The resulting conception will inherit elements from pragmatist and ‘QBist’ approaches, but also differ from them in crucial respects. Furthermore, going beyond the Friedmanian program, I will show how non-fundamental and approximate symmetries can be relevant for identifying constitutive principles.     

Quantum sidelights on The Material Theory of Induction

John Norton's The Material Theory of Induction bristles with fresh insights and provocative ideas that provide a much needed stimulus to a stodgy if not moribund field. I use quantum mechanics (QM) as a medium for exploring some of these ideas. First, I note that QM offers more predictability than Newtonian mechanics for the Norton dome and other cases where classical determinism falters. But this ability of QM to partially cure the ills of classical determinism depends on facts about the quantum Hamiltonian operator that vary from case to case, providing an illustration of Norton's theme of the importance of contingent facts for inductive reasoning. Second, I agree with Norton that Bayesianism as developed for classical probability theory does not constitute a universal inference machine, and I use QM to explain the sense in which this is so. But at the same time I defend a brand of quantum Bayesianism as providing an illuminating account of how physicists' reasoning about quantum events. Third, I argue that if the probabilities induced by quantum states are regarded as objective chances then there are strong reasons to think that fair infinite lotteries are impossible in a quantum world.     

量子系统科学的重要分支:量子控制论

本文针对量子通信和量子计算等量子信息学的发展趋势,全面阐述量子系统科学的重要研究方向——以研究微观世界系统量子态的控制问题的新兴边缘学科--量子控制论.文中先从量子信息论引出量子控制论,进而对量子控制的定义、特点、研究现状、研究内容进行了系统的阐述,并提出了一些新的研究思路。