PNAS ： 'Blurred times' in a quantum world March 9, 2017 Significance We find that there exist fundamental limitations to the joint measurability of time along neighboring space–time trajectories, arising from the interplay between quantum mechanics and general relativity. Because any quantum clock must be in a superposition of energy eigenstates, the mass–energy equivalence leads to a trade-off between the possibilities for an observer to define time intervals at the location of the clock and in its vicinity. This effect is fundamental, in the sense that it does not depend on the particular constitution of the clock, and is a necessary consequence of the superposition principle and the mass–energy equivalence. We show how the notion of time in general relativity emerges from this situation in the classical limit. Whenmeasuring time, we normally assume that clocks do not affect space and time,and that time can be measured with infinite accuracy at nearby points in space.However, combining quantum mechanics and Einstein's theory of generalrelativity theoretical physicists from the University of Vienna and theAustrian Academy of Sciences have demonstrated a fundamental limitation for ourability to measure time. The more precise a given clock is, the more itblurs the flow of time measured by neighbouring clocks. As aconsequence, the time shown by the clocks is no longer well defined. Thefindings are published in the Proceedings of the National Academy of Sciences of the United States of America ( PNAS ). In everyday life we are used to the idea that properties of an object can be knownto an arbitrary precision. However, in quantum mechanics, one of the majortheories in modern physics, Heisenberg's uncertainty principle asserts a fundamental limit to the precision with which pairs of physicalproperties can be known, such as the energy and time of a clock. The more precise the clock is, the larger is the uncertainty in its energy. Anarbitrarily precise clock would therefore have an unbounded uncertainty in itsenergy. This becomes important when including Einstein's theory of generalrelativity, the other key theory in physics, into the picture. Generalrelativity predicts that the flow of time is altered by the presence of massesor sources of energy. This effect, known as gravitational timedilation, causes time to run slower near an object of large energy, ascompared to the situation in which the object has a smaller energy. Puttingthe pieces together Combining these principles from quantum mechanics and general relativity, the researchteam headed by ?aslav Brukner from the University of Vienna and the Instituteof Quantum Optics and Quantum Information demonstrated a new effect at theinterplay of the two fundamental theories. According to quantum mechanics, if we have a very precise clock its energy uncertainty is very large. Due togeneral relativity, the larger its energy uncertainty the larger theuncertainty in the flow of time in the clock's neighbourhood. Putting thepieces together, the researchers showed that clocks placed next to one anothernecessarily disturb each other, resulting eventually in a blurredflow of time. This limitation in our ability to measure time is universal, inthe sense that it is independent of the underlying mechanism of the clocks orthe material from which they are made. Our findings suggest that we needto re-examine our ideas about the nature of time when both quantum mechanics and general relativity aretaken into account, says Esteban Castro, the lead author of thepublication. More information: Esteban Castro Ruiz, Flaminia Giacomini, Caslav Brukner. Entanglementof quantum clocks through gravity （点击可以免费下载原文） . Proceedings of theNational Academy of Sciences ， March 7 2017 ， DOI:10.1073/pnas.1616427114 Explorefurther: Oneclock with two times: When quantum mechanics meets general relativity
International Journal of Quantum Foundations (ISSN 2375-4729) is devoted to all aspects of the foundations of quantum theories, including conceptual and mathematical foundations of quantum mechanics, quantum field theory and quantum gravity. Its aim is to promote quantum foundations research by providing a problem-oriented and debate-encouraged forum for researchers. The journal includes publication of normal papers and reviews, research notes, discussion notes, reminiscences, book chapters, and book reviews.
NATURE | NEWS FEATURE Quantum physics: The quantum atom ———————— 详见 Nature 498, 21 (06 June 2013) doi:10.1038/498021a Related stories and links From nature.com Theoretical physics: Sizing up atoms 05 June 2013 History: The path to the quantum atom 05 June 2013 Bohr's model: Extreme atoms 05 June 2013 Physics: The enigmatic electron 05 June 2013 Nature special: Bohr's atom Nature special: Alan Turing =================================== 附件（pdf） Quantum physics The quantum atom.pdf Theoretical physics Sizing up atoms.pdf History The path to the quantum atom.pdf Bohr's model Extreme atoms.pdf Physics The enigmatic electron.pdf
关键字：全息原理、生物演化、量子物理、信息流、隐序、等级性、全息面 Q: How should we build complex forms, such as living things? A: Organise them as a hierarchy of stable subassemblies, or homologous organs. Q: Surely the genes are all you need to explain living organisation? A: But the same organ can be the result of different genes! When we look at the genes as more than simply stretches of nucleic acid, but see them switching each other on and off, then a hierarchical organisation emerges spontaneously. Q: Anyway, hadn’t Darwin explained homology? A: No, his explanation fails, and the pre-Darwinian understanding of homology is much closer to the hierarchical approach. Q: Isn’t there a quantitative approach that explains form? A: No, form is a qualitative distinction between an inside and an outside. Living things are autonomous forms, themselves maintaining this boundary. Q: Is such a boundary a purely material skin? A: A boundary can be seen as the interface between the parts inside and the rest of the universe outside, through which information flows. Q: Can’t an organism be described in isolation? A: But then it would be a stone! An organism is a process of interaction with its environment, a process of creating and discovering. Q: Creating and discovering? Is that a linguistic process? A: Yes, a living thing is a focus of a linguistic process, where meanings are recognised and transformed. Q: Eventually we will be able to reduce form to physics and chemistry, won’t we? A: Could you reduce the meaning of these words to the chemistry of the ink? The same form may be realised in many different physicochemical configurations. The Cartesian method just won’t work. Q: Do you mean to say that genetic and morphological descriptions of living things are radically different? A: Yes, they are complementary yet incompatible. Continuity of morphological information is a kind of memory without mechanical storage. Without this holistic memory, the mechanically stored genetic information would deteriorate over time. Q: I know that many quantitative models of morphogenesis have been proposed. So how can you say that form is qualitative? A: Morphogenetic models exhibit bifurcation points, where the system shifts suddenly from one form to a quite different form. Q: I feel uncomfortable with this idea of sudden jumps. A: You feel happy about the sudden jumps in quantum physics, don’t you? Q: But how do you decide between all the different interpretations? A: Things become a lot clearer once you understand that the most important thing is the form of the quantum system, not the energy. Q: Isn’t that a very organic way of putting things? A: Yes, the ageing of a living system is much closer to the development of a quantum process than to anything Newton described. Q: But how deep could the comparison be? A: Well, certain forms of the equations for both look very similar, the same equations that describe a hologram. You can talk about a quantum process as a hierarchy of surfaces through which information flows. Q: ‘Surfaces through which information flows’—that’s how you described living things and their organs, isn’t it? A: Yes, that’s right! And these surfaces turn out to be holographic. Q: Oh so that’s where the holographic principle in your title comes from? A: Yes, the holographic principle may hold the key to bringing quantum physics together with relativity. Looks like it might bring in life and non-linear systems too! 摘自 斯蒂芬 * 邬德（2005）的 《 生物演化和量子物理学中的全息原理 》。
Quantum physics is admittedly the most difficult subject to understand. Physicists, let alone students and laymen, are still puzzled by it today. As Richard Feynman once famously claimed, nobody understood quantum mechanics. The crux of the matter lies in the meaning of the mysterious wave function in the theory. An electron is represented by a wave function. But it remains unclear what physical state the mathematical wave function represents. Exactly what is an electron? Is it a spreading wave or a localized particle? If the electron is still a particle, then how does it move? e.g. how does a single electron pass through two slits? Understanding Quantum Mechanics by Shan Gao.pdf This book will show that the real meaning of the wave function can already be unveiled based on the established parts of quantum mechanics. It turns out that electrons are still localized particles, but their motion is not continuous but discontinuous and random, displaying wave-like behavior. For example, in the double-slit experiment with single electrons, each electron passes through two slits at the same time in a random and discontinuous way. Moreover, the book also answers another three fundamental questions about quantum mechanics. How come the Schrdinger equation? Does the wave function collapse during a measurement? If yes, then why and how? Is quantum mechanics compatible with special relativity? If not, then how to solve the incompatibility problem? The original ideas of this book, if confirmed, may finally unveil the mysterious quantum world and make quantum physics comprehensible for everyone. Book Thoughts Reviews This is an ambitious work that reflects admirable grip, and distinctive take, on much of the contemporary philosophy of quantum mechanics literature. ---- Reviewer of Philosophy of Science The idea of using discontinuous motion as a realist interpretation of quantum mechanics is original. ---- Reviewer of Foundations of Physics If it goes through, this would be an original and significant contribution to the debate over the nature of motion. ---- Reviewer of American Philosophical Quarterly Its very existence is at any rate, an excellent illustration of the extent to which physical data force us to depart from commonsense ideas when we try to depict reality “as it really is”. ---- Bernard d'Espagnat, Templeton Prize 2009 Laureate, author of Conceptual Foundations of Quantum Mechanics and On Physics and Philosophy 本书 电子版 （ ebook ）由 Amazon 于去年 11 月出版， 中英文纸印本将会扩充一些内容，计划于明年出版。 欢迎大家对书稿多提意见和建议。
普渡大学的一位物理学者观察到了可以证明神秘Majorana费米子存在的证据,这是一种可以释放容错量子计算潜力的特殊粒子 2012-9-26 Elizabeth K. Gardner Leonid Rokhinson是物理学副教授,带领了一个小组成功演示了分数交流Josephson 效应,这是Majorana粒子存在的信号. "这是凝聚态学者要找的粒子,就像高能学者要找Higgs."Rokhinson说."这是一个奇诡的粒子,它是费米子,同时也是自己的反粒子,既无质量,亦无电荷." 寻找Majorana费米子的动力来自它们的潜在用途,它们可以解决困扰量子计算的信息编码问题.量子位元的载流子是量子计算的基本信息单元,它们非常敏感,容易被附近环境的干扰破坏.Majorana费米子可以保护负载其上的信息不被干扰破坏,构造出更为可靠的量子位元和容错量子计算方法,他说. "信息可以储存在粒子的关联组态上而不必是独立粒子上,所以一个粒子被附近的力稍微干扰一下没有关系,"Rokhinson说."只要局部噪声没有强到足以改变一组粒子的全部组态,信息就安全.这是一种全新的信息处理方法." Majorana费米子还可以保留相互作用的历史记录,应用到量子信息编码上,他说. "其他粒子是可交换的,如果交换两个电子的位置,就像没事发生一样,但交换两个Majorana费米子,将会在量子力学态上留下印记,"Rokhinson说."这就像护照上的印章,记录着粒子是如何抵达它现在的位置的." Rokhinson观察到了Josephson效应的一个变化,那是Majorana费米子的标志.Josephson效应是外加电压下的交流电通过两个超导体时出现的.反过来一样成立:振荡电流产生特定类型的电压,电压与频率成正比.Majorana费米子的存在使频率-电压关系改变了两倍,这叫分数交流Josephson效应,他说. Rokhinson把一维半导体和超导体耦合成组合纳米线,Majorana粒子预计会在其中形成.当交流电通过一组这种纳米线,特别的电压在器件中形成,这就是Rokhinson测量到的电压.外加磁场由弱到强变化,电压随之变化,比原先的变化幅度大了两倍,这是Majorana粒子的标记,他说. Victor Yakovenko,马里兰大学的物理学教授,是预言分数交流Josephson效应的理论家之一. 这个效应是非凡的,特别对应着Majorana粒子,这项测量比其他方法更具决定性,他说. "Majorana粒子是唯一能产生这种效应的粒子,实验上的发现是一个伟大的突破,"Yakovenko说."当然,需要时间和独立的证据来确认它,但此时已足够令人激动." 这个独特状态的发现不意味着容错量子计算会马上实现,Yakovenko说. "这些粒子对量子计算有没有用还有待观察,但尝试的过程会使我们明白量子物理的更多秘密,"他说."量子力学拓扑效应的大门正向人们打开." 细节工作将发表在下一期 Nature Physics 上,现在已经可以在线阅览了.共同作者包括圣母大学的Xinyu Liu,Jacek Furdyna,他们设计了实验中用到的材料.Furdyna也获得过普渡的荣誉学位.这项工作部分地接受了陆军研究办公室和国家自然科学基金的资助. Rokhinson计划进行后续实验,修改系统,以探测新状态的不同性质. 更多信息: The Fractional ac Josephson Effect in a Semiconductor-Superconductor Nanowire as a Signature of Majorana Particles, Nature Physics, 2012. 原文 http://phys.org/news/2012-09-signature-long-sought-particle-revolutionize-quantum.html
【内容简介】量子理论是现代物理科学中最重要和最成功的理论之一，但其产生的概念和哲学问题极其深奥，犹如一座“迷宫”。作者希望通过本书带领读者游览这座迷宫。 本书简述了量子理论的发展史和基本理论，探讨了它的概念和哲学问题，综述了量子理论正统诠释以外的其他诠释 (制导波、退相干、多世界、上帝等)，互补性和量子非定域性的最新实验检验，量子宇宙学和量子引力，以及量子纠缠在计算、密码和隐形传态等方面潜在应用的前沿。阅读本书的过程好像是在徐徐打开一幅多维度多层次的长长的画卷，而且这是一幅未见也不可预见其尽头的画卷，留给读者自己思索和判断的广阔空间。 【读者对象】 本书是一本严肃和具有一定深度的科普著作，有助于启迪思维和提高科学品味。本书可作为大学生和研究生在科学和自然哲学方面的参考书，其他科学和哲学爱好者必定也可从中获益匪浅。 【作者简介】 作者 吉姆·巴戈特 1957年出生在英国的南安普敦，1978年毕业于曼彻斯特大学的化学专业。他在牛津大学获得了物理化学博士学位，之后在牛津大学和斯坦福大学进行博士后研究工作。二十年来，他一直学习和写作科学、哲学和科学史方面的知识，并在科学研究和写作领域都赢得了众多奖项。他的著名作品有 The Quantum Story ， A Beginner’s Guide to Reality 以及 Beyond Measure ：Modern Physics, Philosophy, and the Meaning of Quantum Theory 。 译者 潘士先 男，1935年9月生，浙江湖州人。1950年2月~1952年7月就读于湖州中学，后考入天津大学电力系，1956年毕业后分配到北京航空学院(现为北京航空航天大学)任教，后任北京航空航天大学电子工程系教授，现退休多年。1981~1983年期间曾在美国普渡大学(Purdue University)为访问学者两年余。他的主要著作有《谱估计与自适应滤液》、《电路分析》，并在国际著名期刊发表论文多篇。曾获美国IEEE声学、语音和信号处理学会 (Acoustics, Speech and Signal Processing Society)1984年度最佳论文奖。现感兴趣于物理和数学方面的科普读物。
今天刚刚完成论文 薛定谔方程的推导 。或许，39岁的我终于推导出了薛定谔在39岁时发现的那个优美的方程。或许，这仍只是漫长探索旅程中的一个驿站。那旅程是孤独的，但却充溢着发现的快乐。就像一个孩童拾到一枚美丽的贝壳，就像一位老人邂逅青年时代的自我。---- 高山，2010年10月22日夜于悉尼卡尔顿 提起薛定谔，我总想起1959年11月那个寒冷的冬夜。由于支气管炎复发薛定谔难以入睡。于是，他打开灯在桌前给好友辛格写了一封长信。在信中他说：除了几个人（如爱因斯坦、劳厄）以外，其余的理论物理学家都是纯粹的笨人，而我是唯一活下来的健全的人。那个日夜折磨我们的伟大谜题就是波粒二象性。在过去的十年里，关于它我写了很多文章，并且几乎厌倦了这样做就我个人而言，结果是无价值的因为大多数我最亲近的同行（理论物理学家）已经形成了这样的见解，即我仍在留恋我生命中最伟大的成功（波动力学），它是在我仍具有可自由支配的智慧的时候（1926年，那时我39岁）发现的，因此他们说，我坚持一切都是波的观点，衰老使我不能理解（玻尔的）互补性这一伟大发现因此，一般的物理学家不能相信，任何健全的人会拒绝接受哥本哈根神谕。是的，薛定谔不理解他所发现的波函数及其演化方程，但他一直努力去揭示它们的意义；而其他一些物理学家，尽管实际上也并不理解，但却以为理解了，从而停止不前。对此，我最喜欢薛定谔那句铿锵有力的呐喊：我们不能在时空中理解的东西，我们根本就无法理解。或许， 非连续运动的物理图像 最终会让薛定谔满意。 对于普通读者，薛定谔最让人感兴趣的方面可能还是他的猫和女人。人们至今仍在关注那只著名的薛定谔猫的命运，它究竟是死是活呢？而1925年圣诞节在阿罗萨(Arosa)与他一起度假的神秘女人至今也仍然是一个谜。 关于薛定谔的生平和思想，他的猫和女人，推荐阅读W. Moore, Schr dinger: Life and Thought (Cambridge: Cambridge University Press, 1989).
《上帝真的掷骰子》一书在5月初进行了第二次印刷。最近有读者来信，希望能够看到非连续运动理论的更严密的数学论证。在此我列出几篇相关的研究论文供参考。 S. Gao (2010), The wave function and quantum reality , to appear in the Proceedings of the Conference Advances in Quantum Theory 2010. S. Gao (2010), On Disi-Penrose Criterion of Gravity-Induced Quantum Collapse, International Journal of Theoretical Physics 49, 849853. ( http://www.springerlink.com/content/j54r75r28w04p03h/ ) S. Gao (2010), Meaning of the wave function, arXiv:1001.5085. An extended version is available on http://philpapers.org/rec/GAOMOT . S. Gao (2006), A model of wavefunction collapse in discrete space-time, International Journal of Theoretical Physics 45, 1965-1979. ( http://www.springerlink.com/content/p84722072t6805rl/ ) S. Gao (2006), Quantum Motion: Unveiling the Mysterious Quantum World. Bury St Edmunds: Arima Publishing. S. Gao (2006), What quantum mechanics really describes: discontinuous motion of particles, Galilean Electrodynamics 17 (1), 3-10. S. Gao (2004), A Suggested Interpretation of the Quantum Theory in Terms of Discontinuous Motion of Particles, NeuroQuantology 2(3), 190-209. S. Gao (2001), From quantum motion to classical motion---seeking the lost reality, Physics Essays 14 (1), 37-48.
量子隐形传送与量子远程通信密切相关。teleportation一词是指一种无影无踪的传送过程。爱因斯坦曾把这种来无踪，去无影的东西成为鬼魅（spooky），这种鬼魅般的超距作用(spooky action at a distance)在众多实验中一再出现，因此直到过世前他都没有完全接受量子力学是一个真实而完备的理论，一直尝试找到一种更加合理的诠释。爱因斯坦是位实在论者，他不接受这种spooky的现象是可以理解的。 然而，爱因斯坦所怀疑的，却在上个世纪末被量子物理学家从某种意义上实现了。1993年美国物理学家提出了量子隐形传态的方案。将某个粒子的未知量子态（即未知量子比特）传送到另一个地方，把另一个粒子制备到这个量子态上，而原来的粒子仍留在原处。其基本思想是：将原物的信息分成经典信息和量子信息两部分，它们分别经由经典通道和量子通道传送给接收者。经典信息是发送者对原物进行某种测量而获得的，量子信息是发送者在测量中未提取的其余信息。接收者在获得这两种信息之后，就可制造出原物量子态的完全复制品。这个过程中传送的仅仅是原物的量子态，而不是原物本身。发送者甚至可以对这个量子态一无所知，而接收者是将别的粒子（甚至可以是与原物不相同的粒子）处于原物的量子态上。在经典的世界中人们可以复制并传输信息，日常生活中我们每天都会用到，比如传真机。而在量子世界中，量子信息只能由载体传递，不能被复制，无法使用类似传真的普通传输方式。在传递信息的过程中，量子隐形传态无须复制所传信息，而是提供了一种传递量子信息的方法，这也是量子纠缠在实际应用中最引人注目的方案之一。 从物理学角度，可以这样来想象隐形传送的过程：先提取原物的所有信息，然后将这些信息传送到接收地点，接收者依据这些信息，选取与构成原物完全相同的基本单元（如原子），制造出原物完美的复制品。遗憾的是，量子力学的不确定性原理不允许精确地提取原物的全部信息，这个复制品不可能是完美的。因此长期以来，隐形传物只不过是种幻想而已。 1997年年底奥地利的一个研究小组首先在实验上演示成功了量子隐形传送，论文发表在《自然》上，引起国际学术界的极大兴趣。此后，有若干研究小组也相继在实验上实现了量子隐形传送，包括中国科技大学的研究小组。 量子隐形传送所传输的是量子信息，它是量子通信最基本的过程。人们基于这个过程提出了实现量子因特网的构想。量子因特网是用量子通道来联络许多量子处理器，它可以同时实现量子信息的传输和处理。相比于现在经典因特网，量子因特网具有安全保密特性，可实现多端的分布计算，有效地降低通信复杂度等一系列优点。2009年，美国马里兰州立大学联合量子研究所的科学家成功地实现了从一个原子到1米外的一个容器里的另一个原子的量子隐形传输，这一突破向《星际迷航》描述的科幻情节又迈进了一步。当然，这个被称作量子信息处理的试验与科幻电影中传输身体的技术不可同日而语，因为一个原子只是转变成另一个原子，这样，第二个原子变扮演起第一个原子的角色。尽管如此，原子对原子的传输对于研制超密超快的计算机仍具有重在意义。这一成果被美国《时代周刊》评为2009年十大科学进展之一。
标签: 量子物理
