路易·德布罗意Louis de Broglie

路易·德布罗意的父亲是Victor，德布罗意，母亲是Pauline d'Armaillé。德布罗意在巴黎的Lycée Janson de Sailly学习，于1909年完成中学教育。在这个阶段，他并没有设想从事科学事业，而是有兴趣在大学学习文学。他进入巴黎的索邦大学学习历史课程，打算为自己在外交部门谋一份职业。18岁时，他获得了文学学位，但他已经开始对数学和物理产生兴趣。在被分配了一个历史研究课题后，他经过极大的犹豫，选择了攻读理论物理学位。

1913年，德布罗意获得了理学学士学位，但在他的事业进一步发展之前，第一次世界大战爆发了。战争期间，德布罗意在军队服役。整个战争期间，他都隶属于无线电报部门，并在埃菲尔铁塔的站点服役。在这些战争岁月里，他所有的业余时间都用来思考技术问题。他解释了战后自己如何被数学物理吸引（例如见[9]）：-

当我在1920年恢复学业时……吸引我……走向理论物理的是……物质结构和辐射结构越来越被笼罩其中的神秘，随着马克斯·普朗克于1900年在他对黑体辐射的研究中引入的奇怪的quantum概念，日益深入到整个物理学中。

德布罗意虽然从事数学物理研究，但仍对实验物理保持兴趣。他的兄弟Maurice 德布罗意当时正在进行X射线的实验工作，这在20世纪20年代初的几年里对德布罗意产生了相当大的兴趣，期间他正在攻读博士学位。De Broglie1924年的学位论文Recherches sur la théorie des quanta Ⓣ（量子理论研究）提出了基于阿尔伯特·爱因斯坦和马克斯·普朗克工作的电子波理论。它提出了他最著名的理论，即物质具有粒子和波两种性质的粒子-波二象性理论。

在1929年获得诺贝尔奖时的一次演讲中，德布罗意解释了他学位论文中思想的背景（例如见[9]）：-

三十年前，物理学分为两大阵营：……基于粒子和原子概念的物质物理学，这些粒子和原子被认为服从经典牛顿力学定律；以及基于波在假想连续介质——光以太和电磁以太——中传播思想的辐射物理学。但这两个物理学体系不能彼此脱离：它们必须通过制定物质与辐射之间能量交换的理论而统一起来。……在试图将两个物理学体系结合起来的尝试中，实际上得出了既不正确、甚至应用于物质与辐射之间的能量平衡时也不可接受的结论……马克斯·普朗克……假设……一个光源……以相等且有限的量——量子——发射其辐射。马克斯·普朗克思想的成功伴随着严重的后果。如果光以量子形式发射，那么一旦发射，它难道不具有微粒结构吗？……詹姆斯·琼斯和儒勒·昂利·庞加莱[表明]如果光源中物质粒子的运动按照经典力学定律进行，那么就无法得到正确的黑体辐射定律，即马克斯·普朗克定律。

在1963年的一次采访中，德布罗意描述了在上述背景下，他的发现是如何产生的：-

正如在我与兄弟的交谈中，我们总是得出结论：在X射线的情况下，既有波又有微粒，因此突然——……在1923年夏天期间确定——我想到必须将这种二象性扩展到物质粒子，特别是电子。我意识到，一方面，威廉·哈密顿-卡尔·古斯塔夫·雅各布·雅可比理论在某种程度上指向那个方向，因为它可以应用于粒子，此外，它代表一种几何光学；另一方面，在量子现象中，人们获得量子数，这在力学中很少见，但在波现象以及所有涉及波运动的问题中非常频繁地出现。

电子的波动性质于1927年由美国的C J Davisson、C H Kunsman和L H Germer以及苏格兰阿伯丁的G P Thomson（J J Thomson之子）通过实验证实。德布罗意的电子物质波理论后来被埃尔温·薛定谔、保罗·狄拉克等人用于发展波动力学。

获得博士学位后，德布罗意留在索邦大学任教两年，并于1928年成为儒勒·昂利·庞加莱研究所的理论物理学教授。从1932年起，他同时担任索邦大学理学院的理论物理学教授。De Broglie在那里任教直到1962年退休。从1944年起，他是经度局的成员。1945年，他成为法国原子能委员会的顾问。

他最大的荣誉是在1929年获得诺贝尔奖。我们在上面引用了他颁奖典礼上的演讲。让我们进一步引用演讲中的内容（例如参见[9]）：-

因此，我得出了以下指导我研究的一般观念：对于物质，正如对于辐射，特别是光一样，我们必须同时引入微粒概念和波概念。换句话说，在两种情况下，我们都必须假设存在伴随波的微粒。但微粒和波不能是独立的，因为根据玻尔，它们是互补的；因此，必须在微粒的运动与与之相关的波的传播之间建立某种平行关系。

1929年获得诺贝尔奖后，德布罗意致力于波动力学的扩展。在许多主题的出版物中，他发表了关于保罗·狄拉克的电子理论、新光理论、乔治·乌伦贝克的自旋理论以及波动力学在核物理中的应用的著作。他写了至少二十五本书，包括Ondes et mouvements Ⓣ（波与运动）（1926年）、La mécanique ondulatoire Ⓣ（波动力学）（1928年）、Une tentative d'interprétation causale et non linéaire de la mécanique ondulatoire: la théorie de la double solution Ⓣ（非线性波动力学的因果解释：双解理论）（1956年）、Introduction à la nouvelle théorie des particules de M Jean-Pierre Vigier et de ses collaborateurs Ⓣ（让-皮埃尔·维吉耶及其合作者的新粒子理论导论）（1961年）、Étude critique des bases de l'interprétation actuelle de la mécanique ondulatoire Ⓣ（对当前波动力学解释基础的批判性研究）（1963年）。最后提到的三本书以英文译本出版，分别为Non-linear Wave Mechanics: A Causal Interpretation（1960年）、Introduction to the Vigier Theory of elementary particles（1963年）和The Current Interpretation of Wave Mechanics: A Critical Study（1964年）。

他写了许多通俗著作，展示了他对现代物理学哲学意义的兴趣，包括Matter and Light: The New Physics（1939）；The Revolution in Physics（1953）；Physics and Microphysics（1960）；以及New Perspectives in Physics（1962）。

1933年，德布罗意当选为Académie des Sciences院士，并于1942年成为数学科学部的终身秘书。Académie于1929年授予他儒勒·昂利·庞加莱奖章，并于1932年授予他摩纳哥亚伯拉罕·阿德里安·艾伯特一世奖。他获得的其他荣誉包括1952年联合国教科文组织授予他的卡林加奖，以表彰他为公众理解现代物理学所做的努力。法国国家科学研究中心于1956年授予他金质奖章。进一步的荣誉包括授予他荣誉军团大十字勋章，比利时授予他利奥波德勋章军官勋位。他获得了华沙大学、布加勒斯特大学、雅典大学、洛桑大学、魁北克大学和布鲁塞尔大学的荣誉博士学位。他当选为欧洲、印度和美国的十八个科学院和学术团体的荣誉成员。

德布罗意这样描述自己：-

... 更像一个纯理论家，而不是实验家或工程师，尤其喜欢一般的和哲学的观点 ...。

德布罗意一生中的核心问题是，原子物理学的统计性质究竟反映了对底层理论的无知，还是统计就是所能知道的一切。他一生中大部分时间相信前者，尽管作为年轻研究者他起初相信统计掩盖了我们的无知。也许令人惊讶的是，他在晚年又回到了这一观点，说道：-

……统计理论在逃避我们实验技术的变量背后，隐藏着一个完全确定且可探知的实在。

让我们以瑞典皇家科学院诺贝尔物理学委员会主席C W Oseen对德布罗意的致敬来结束我们的传记：-

当你还很年轻时，你就投身于围绕物理学最深刻问题的激烈争论中。你大胆断言，在没有任何已知事实支持的情况下，物质不仅具有微粒性质，还具有波的性质。实验后来出现并证实了你观点的正确性。你为一个已经享有数百年荣誉的名字增添了新的荣耀。

Louis de Broglie's father was Victor, Duc de Broglie, and his mother was Pauline d'Armaillé. Louis studied at the Lycée Janson de Sailly in Paris completing his secondary school education in 1909. At this stage he did not envisage a career in science, but was interested in taking literary studies at university. He entered the Sorbonne in Paris taking a course in history, intending to make for himself a career in the diplomatic service. At the age of 18 he graduated with an arts degree but he was already becoming interested in mathematics and physics. After being assigned a research topic in history he chose, after worrying greatly about the decision, to study for a degree in theoretical physics.

In 1913 de Broglie was awarded his Licence ès Sciences but before his career had progressed much further World War I broke out. During the War de Broglie served in the army. He was attached to the wireless telegraphy section for the whole of the war and served in the station at the Eiffel Tower. During these war years all his spare time was spent thinking about technical problems. He explained how he was attracted to mathematical physics after the War (see for example [9]):-

When in 1920 I resumed my studies ... what attracted me ... to theoretical physics was ... the mystery in which the structure of matter and of radiation was becoming more and more enveloped as the strange concept of the quantum, introduced by Planck in 1900 in his researches into black-body radiation, daily penetrated further into the whole of physics.

Taking up research in mathematical physics, de Broglie nevertheless maintained an interest in experimental physics. His brother Maurice de Broglie was at that time carrying out experimental work on X-rays and this proved a considerable interest to de Broglie during the first few years of the 1920s during which he worked for his doctorate. De Broglie's doctoral thesis Recherches sur la théorie des quanta Ⓣ of 1924 put forward this theory of electron waves, based on the work of Einstein and Planck. It proposed the theory for which he is best known, namely the particle-wave duality theory that matter has the properties of both particles and waves.

In a lecture de Broglie gave on the occasion when he received the Nobel Prize in 1929 he explained the background to the ideas contained in his doctoral thesis (see for example [9]):-

Thirty years ago, physics was divided into two camps: ... the physics of matter, based on the concepts of particles and atoms which were supposed to obey the laws of classical Newtonian mechanics, and the physics of radiation, based on the idea of wave propagation in a hypothetical continuous medium, the luminous and electromagnetic ether. But these two systems of physics could not remain detached from each other: they had to be united by the formulation of a theory of exchanges of energy between matter and radiation. ... In the attempt to bring the two systems of physics together, conclusions were in fact reached which were neither correct nor even admissible when applied to the energy equilibrium between matter and radiation ... Planck ... assumed ... that a light source ... emits its radiation in equal and finite quantities - in quanta. The success of Planck's ideas has been accompanied by serious consequences. if light is emitted in quanta, must it not, once emitted, possess a corpuscular structure? ... Jeans and Poincaré [showed] that if the motion of the material particles in a source of light took place according to the laws of classical mechanics, then the correct law of black-body radiation, Planck's law, could not be obtained.

During an interview in 1963 de Broglie described how, given the above background, his discoveries came about:-

As in my conversations with my brother we always arrived at the conclusion that in the case of X-rays one had both waves and corpuscles, thus suddenly - ... it was certain in the course of summer 1923 - I got the idea that one had to extend this duality to material particles, especially to electrons. And I realised that, on the one hand, the Hamilton-Jacobi theory pointed somewhat in that direction, for it can be applied to particles and, in addition, it represents a geometrical optics; on the other hand, in quantum phenomena one obtains quantum numbers, which are rarely found in mechanics but occur very frequently in wave phenomena and in all problems dealing with wave motion.

The wave nature of the electron was experimentally confirmed in 1927 by C J Davisson, C H Kunsman and L H Germer in the United States and by G P Thomson (the son of J J Thomson) in Aberdeen, Scotland. De Broglie's theory of electron matter waves was later used by Schrödinger, Dirac and others to develop wave mechanics.

After his doctorate, de Broglie remained at the Sorbonne where he taught for two years, becoming professor of theoretical physics at the Henri Poincaré Institute in 1928. From 1932 he was also professor of theoretical physics at the Faculté des Sciences at the Sorbonne. De Broglie taught there until he retired in 1962. From 1944 he was a member of the Bureau des Longitudes. In 1945 he became an adviser to the French Atomic Energy Commissariat.

His greatest honour was being awarded the Nobel Prize in 1929. We have quoted above from his lecture given at the award ceremony. Let us quote further from the lecture (see for example [9]):-

Thus I arrived at the following general idea which has guided my researches: for matter, just as much as for radiation, in particular light, we must introduce at one and the same time the corpuscle concept and the wave concept. In other words, in both cases we must assume the existence of corpuscles accompanied by waves. But corpuscles and waves cannot be independent, since, according to Bohr, they are complementary to each other; consequently it must be possible to establish a certain parallelism between the motion of a corpuscle and the propagation of the wave which is associated with it.

After receiving the Nobel Prize in 1929 De Broglie worked on extensions of wave mechanics. Among publications on many topics he published work on Dirac's theory of the electron, on the new theory of light, on Uhlenbeck's theory of spin, and on applications of wave mechanics to nuclear physics. He wrote at least twenty-five books including Ondes et mouvements Ⓣ (1926), La mécanique ondulatoire Ⓣ (1928), Une tentative d'interprétation causale et non linéaire de la mécanique ondulatoire: la théorie de la double solution Ⓣ (1956), Introduction à la nouvelle théorie des particules de M Jean-Pierre Vigier et de ses collaborateurs Ⓣ (1961), Étude critique des bases de l'interprétation actuelle de la mécanique ondulatoire Ⓣ (1963). The last three mentioned books were published in English translations as Non-linear Wave Mechanics: A Causal Interpretation (1960), Introduction to the Vigier Theory of elementary particles (1963), and The Current Interpretation of Wave Mechanics: A Critical Study (1964).

He wrote many popular works which demonstrate his interest in the philosophical implications of modern physics, including Matter and Light: The New Physics (1939); The Revolution in Physics (1953); Physics and Microphysics (1960); and New Perspectives in Physics (1962).

In 1933 de Broglie was elected to the Académie des Sciences becoming Permanent Secretary for the mathematical sciences in 1942. The Académie awarded him its Henri Poincaré Medal in 1929 and the Albert I of Monaco Prize in 1932. Other honours which he received included the Kalinga Prize which was awarded to him by UNESCO in 1952 for his efforts towards the understanding of modern physics by the general public. The French National Scientific Research Centre awarded him its gold medal in 1956. Further honours included the awarding of the Grand Cross of the Légion d'Honneur and Belgium made him an Officer of the Order of Leopold. He received honorary doctorates from the Universities of Warsaw, Bucharest, Athens, Lausanne, Quebec, and Brussels. He was elected to honorary membership of eighteen academies and learned societies in Europe, India, and the United States.

De Broglie described himself as:-

... having much more the state of mind of a pure theoretician than that of an experimenter or engineer, loving especially the general and philosophical view ... .

The central question in de Broglie's life was whether the statistical nature of atomic physics reflects an ignorance of the underlying theory or whether statistics is all that can be known. For most of his life he believed the former although as a young researcher he had at first believed that the statistics hide our ignorance. Perhaps surprisingly, he returned to this view late in his life stating that:-

... the statistical theories hide a completely determined and ascertainable reality behind variables which elude our experimental techniques.

Let us end our biography with the tribute paid to de Broglie by C W Oseen, Chairman of the Nobel Committee for Physics of the Royal Swedish Academy of Sciences:-

When quite young you threw yourself into the controversy raging round the most profound problem in physics. You had the boldness to assert, without the support of any known fact, that matter had not only a corpuscular nature, but also a wave nature. Experiment came later and established the correctness of your view. You have covered in fresh glory a name already crowned for centuries with honour.