列夫·朗道Lev Landau

列夫·朗道的母亲 Lyubov Veniaminovna Harkavi（1876-1941）接受过医学训练，并从事过生理学工作。她和朋友 Anna 去瑞士度假，遇到了 Anna 的表兄弗洛伦斯·南丁格尔·大卫 Lvovich 列夫·朗道（生于1866年）。Lyubov 和大卫都是犹太人，他们坠入爱河[81]：-

[大卫 Lvovich]是一个沉着克制的人，从不提高嗓门；[Lyubov]精力充沛，脾气急躁，容易激动。但性格相反的人往往能够相容并互补。

他们于1905年结婚，搬到巴库居住，大卫 Lvovich 在那里工作。他是黑海和里海股份公司的石油工程师，在里海沿岸的巴库油田工作。他相当富有，在市中心拥有一套六居室公寓。他们的女儿 Sonya 出生于1906年8月8日，儿子 Lyova（即本传记的主人公，被称为列夫·朗道）出生于1908年1月。孩子出生后，Lyubov Veniaminovna 担任助产士和妇科医生，然后从1911年起，在一所女子高中担任医生。在1915-16年服完战时服务后，她在巴库犹太高中担任自然科学教师。除了工程师的工作外，大卫 Lvovich 还从事研究、撰写科学论文，并且是一位非常出色的数学家。他从小教儿子列夫·朗道数学。Sonya 和列夫·朗道都是非常聪明但非常固执的孩子。

1916年9月，巴库开办了一所犹太中学，八岁的列夫·朗道开始在那里上学。这所学校旨在向犹太儿童教授俄语、希伯来语和圣经研究，但也教授其他全套科目。列夫·朗道在科学和数学方面才华出众，但在希伯来语和意第绪语方面只是平庸。他的同学当时这样描述他：-

他是一个安静、害羞的男孩，尽管他与同学、甚至与老师相处的方式有些居高临下。

此处一段未译出，以下为英文原文 From his mother, Lev learnt French and German and quickly became fluent. He had piano lessons which he hated so he was soon allowed to stop these and study more mathematics. While Lev was at high school, the Russian Revolution took place. Lev was a staunch believer in Communist principles but, as we will see below, came to hate the Soviet leadership. His achievements at school were such that by the age of thirteen he had completed his secondary schooling and had the qualifications to enter university. Although calculus was not part of the school syllabus, Lev had studied this own topic his own and, later in life, would say that he could not remember a time when he was not proficient at differentiation and integration. His parents did not like the idea that he should begin his university studies a such a young age, and this was almost certainly a wise decision on their part. David Lvovich wanted his son to have a career in finance or administration so Lev was sent to Baku Economic Technical School for a year to delay his entry to university studies.

列夫·朗道在1922年进入巴库大学（后称基洛夫阿塞拜疆国立大学）时年仅十四岁，此时他已对数学、物理和化学充满热情。他在该校数理系学习物理，但也学习化学，尽管他在大学教育中没有进一步研究这一主题，但它仍是他终生的兴趣之一。1924年，在巴库大学学习两年后，他转入列宁格勒国立大学，于1927年毕业[66]：-

在列宁格勒——当时苏联物理学的主要中心——他首次接触到真正的理论物理学，当时它正经历一个动荡时期。他以全部青春的热情和热忱投身于其研究，工作如此努力，常常疲惫不堪，以至于晚上无法入睡，因为脑海中仍在翻腾着公式。后来他常描述当时如何被广义相对论的惊人美感所迷住（有时他甚至宣称，初次接触这一理论时的这种狂喜，一般应是任何天生的理论物理学家的特征）。他还描述了阅读维尔纳·海森堡和埃尔温·薛定谔的文章时所感受到的狂喜状态，这些文章标志着新量子力学的诞生。他说，他从中不仅获得了对真正科学魅力的喜悦，还敏锐地意识到人类天才的力量，其最大的胜利在于人能够理解超出其想象范围的事物。

事实上，他的第一篇出版物On the Theory of the Spectra of Diatomic Molecules于1926年印刷出版，当时他还是十八岁的本科生，而他的第二篇论文The Problem of Damping in Wave Mechanics在他毕业那年发表，这是他关于量子理论的第一篇论文。他继续在列宁格勒物理技术研究所进行研究。

1929年，在洛克菲勒基金会奖学金的资助下，列夫·朗道开始了为期十八个月的国外旅行，访问了德国、瑞士、荷兰、英格兰、比利时和丹麦。对他的研究最有价值的访问是前往哥廷根、莱比锡，尤其是哥本哈根，在那里他三次在尼尔斯·玻尔的理论物理研究所工作，分别是1930年4月8日至5月3日、1930年9月20日至11月22日，以及1931年2月25日至3月19日[66]：-

这种科学氛围，加上尼尔斯·玻尔本人人格魅力的放大，决定性地影响了列夫·朗道形成自己的物理学观点。

从那时起，他自认为是尼尔斯·玻尔的学生，正是尼尔斯·玻尔的影响决定了列夫·朗道未来工作的方向[49]：-

……他还从尼尔斯·玻尔那里学到了教学和训练方法。

对哥本哈根的访问似乎也标志着列夫·朗道性格的转变[77]：——

列夫·朗道当时以及此后若干年里，都是一个极其挑衅的年轻人，喜欢惊世骇俗。

在国外旅行期间，他去了苏黎世，1930年12月至1931年1月在那里工作。在那里，他与鲁道夫·佩尔斯（1907—1995）合作研究相对论量子力学，他们的合著论文Quantum Electrodynamics in Configuration Space于1931年发表。列夫·朗道和佩尔斯用德语讨论了许多话题，包括天体物理学。佩尔斯在1977年5月的一次采访中说：——

他显然是一个非常令人印象深刻的人。我的意思是，他的工作方式是——如果他看到一篇感兴趣的论文，他会扫一眼看看问题是什么，然后他就会坐下来自己解决这个问题，并看看他的答案是否与论文一致。

在苏黎世期间，他写了论文On the theory of stars，但直到回到列宁格勒[44]后才提交发表：——

列夫·朗道在四页论文的开篇指出，理论天体物理学家借助数学上方便但物理上不切实际的假设来分析恒星结构是错误的。他通过评论爱德华·亚瑟·米尔恩正在进行的推翻亚瑟·爱丁顿正统恒星模型的活动来说明这一点，该模型将恒星视为气体球，其中向内的引力压力被向外的辐射压力所抵消。……列夫·朗道相信自己已经证明了“天体物理方法”的不合理性，断言“尝试用理论物理学的方法来攻克恒星结构问题是合理的”。

1931年，列夫·朗道回到列宁格勒，在物理技术研究所工作，但次年他被任命为哈尔科夫乌克兰技术研究所理论部主任，同时被任命为哈尔科夫机械工程学院理论物理学讲席。他搬到哈尔科夫就任这些职位，并于1934年获得物理与数学科学博士学位。他在哈尔科夫的第一个项目之一是组织一次理论物理学国际会议，尼尔斯·玻尔出席了这次会议[77]：-

列夫·朗道主持；尼尔斯·玻尔对所有论文展开讨论……

不久之后，列夫·朗道回到哥本哈根参加由尼尔斯·玻尔组织的会议[77]：-

……穿着红色外套，依然挑衅。在接下来的两年里，他以平均每六周一篇的速度产出原创科学论文，涵盖的主题范围惊人。

这种非凡的产出很快得到了回报，因为除了其他职位外，1935年他获得了教授头衔，并被任命为哈尔科夫高尔基国立大学物理学负责人。列夫·朗道很快使他在哈尔科夫的学派成为苏联理论物理学的中心。在哈尔科夫，列夫·朗道遇到了康科尔迪娅·德罗班采娃，一位被称为科拉的化学专业毕业生。她是一名食品技术专家，从1935年起他们以非正式婚姻同居，几年后的1946年，他们的儿子伊戈尔出生时，他们正式结婚。在哈尔科夫，列夫·朗道有一个才华横溢的学生叶夫根尼·利夫希茨，他于1933年开始在其指导下攻读博士学位。叶夫根尼·利夫希茨是一位极具天赋的作家，列夫·朗道与他合作创作了十卷本的《理论物理学教程》。我们将在下面给出更多细节。

1937年，列夫·朗道前往莫斯科，担任苏联科学院物理研究所理论部主任。他研究原子碰撞、天体物理学、低温物理学、原子与核物理学、热力学、量子电动力学、气体动理论、量子场论和等离子体物理学。他关于解释液氦为何具有超流性的理论工作，为他赢得了1962年诺贝尔物理学奖。授奖词称他获得诺贝尔物理学奖是因为：-

……他对凝聚态物质，特别是液氦的开创性理论。

也许液氦在略高于绝对零度的温度下所表现出的奇特行为的一些细节会有所帮助。实验上早已注意到，如果将这些低温下的液氦放入烧杯中，它会爬出烧杯，直到杯外液面与杯内液面齐平。同样，如果杯外液面高于杯内液面，液氦也会爬入烧杯。列夫·朗道提出了一种理论来解释这种行为，并于1941年发表。该理论预言了一种新现象，即被称为“第二声”的温度波，三年后，在莫斯科产生的实验证据证实了“第二声”的存在。

正如我们上面所指出的，列夫·朗道信奉共产主义原则，他在1935年写道，[35]：-

……党和政府为我国物理学的发展提供了前所未有的机会。

然而，他对约瑟夫·斯大林领导国家的方式越来越不满。从1935年开始，斯大林在“大清洗”中开始系统地清除他的反对者。很快，被送往监狱、劳改营或劳动营的，是他的党内领导成员、军方人士以及各行各业的要人。不久，列夫·朗道就受到了克格勃的调查，克格勃从告密者那里得到消息，称他发表了反政府言论。目前尚不清楚他是否是1938年出版的一本攻击该政权的小册子的作者，但即使他不是，也清楚的是他支持并帮助了该小册子的制作。该小册子开头如下[35]：-

十月革命的伟大事业正遭到卑鄙的背叛。这个国家被血流和污秽淹没。数百万无辜的人被投入监狱，没有人能说什么时候会轮到自己。同志们，很明显，斯大林集团已经发动了一场法西斯政变。社会主义只存在于惯于撒谎的报纸版面上。斯大林对真正社会主义的疯狂仇恨，与希特勒和墨索里尼并无不同。

1938年4月28日，列夫·朗道被捕并被带到卢比扬卡监狱。在被迫每天站立七个小时、并被威胁转移到列福尔托沃监狱（那里比卢比扬卡监狱糟糕得多）两个月后，他写下并签署了一份供词。人们不能认真对待在这种情形下产生的文件，但实际上，它似乎确实真实地反映了列夫·朗道的观点。他后来写道：-

我在监狱里待了一年，很明显，我连再活半年都做不到。

俄罗斯科学家试图迫使当局释放他，著名物理学家彼得·卡皮察声称，除非列夫·朗道获释，否则他将停止自己的科学工作。卡皮察和尼尔斯·玻尔都写信给斯大林，坚持必须释放列夫·朗道。他于1939年获释，并恢复为物理问题研究所的研究员。

列夫·朗道 在20世纪40年代后半期参与了苏联原子弹的一些工作。他确实为该项目进行了数学计算，并发表了几篇作为这项工作成果的论文。这不是他想做的工作，但觉得不得不承担，尤其是在几年前被捕和监禁之后。

我们上面提到，列夫·朗道 的一项主要贡献是撰写了许多杰出的教科书和研究专著。他最著名的书是与 叶夫根尼·利夫希茨 合著的十卷本 Course of Theoretical Physics，后者是 列夫·朗道 的研究生。他们从20世纪30年代开始这项工作，书的第一部分基于讲义。叶夫根尼·利夫希茨 在 列夫·朗道 去世后继续撰写这本书，直到1979年才完成。这部著作包含了许多 列夫·朗道 和 叶夫根尼·利夫希茨 多年研究的结果，包括许多合著研究论文的成果。该书的各章表明了他们共同研究的主要主题：力学、场论、量子力学、量子电动力学、经典统计物理学、量子统计物理学、流体力学、弹性理论、连续介质电动力学和物理动力学。

参见 列夫·朗道 和 叶夫根尼·利夫希茨 的序言摘录：Course of Theoretical Physics 在 THIS LINK

参见 列夫·朗道 和 利夫希茨 的书评摘录：Course of Theoretical Physics 在 THIS LINK

让我们提供一些关于列夫·朗道讨论班的信息。在被接纳为列夫·朗道学派成员之前，候选人必须通过列夫·朗道的“理论最低限度”。这是列夫·朗道设置的一系列考试，学生必须花很长时间准备。例如，[45]和[46]的作者鲍里斯·约费花了将近两年时间才通过列夫·朗道的“理论最低限度”。约费在[46]中关于列夫·朗道的讨论班写道：-

成为列夫·朗道的弟子并不意味着任何特权，只有义务。这是因为任何人都可以与列夫·朗道进行科学讨论并获得他的建议。此外，通过列夫·朗道最低限度的人中只有少数成为他的研究生（我不是）。列夫·朗道的学生作为列夫·朗道讨论班的参与者享有充分权利。但同样，任何人都可以参加他的讨论班，提问并发表意见。“充分权利”参与者的义务是按字母顺序定期为讨论班准备综述报告。每次讨论班之后，列夫·朗道会拿一期最近的《物理评论》（当时它还没有分栏），并向即将作报告的人指出他应该在讨论班上报告哪些论文。通常，他会从物理学的所有分支中挑选十几篇这样的论文。……报告人不仅必须综述论文，即呈现其基本思想和最终结果，而且应该很好地理解结果是如何获得的，向听众呈现并解释所有必要的公式，包括实验技术，并对结果是否可靠有自己的看法。……理论报告的报告方式则不同。一个想在讨论班上报告理论研究成果（他自己的或来自文献的）的人，首先应该私下向列夫·朗道讲述。如果列夫·朗道同意这项工作的基本要点，那么就允许在讨论班上作报告。在报告期间，列夫·朗道给出澄清性评论，而且他对这项工作的解释常常与作者的解释大不相同。随后常常会展开热烈讨论。人们可以从列夫·朗道那里听到：“作者实际上并不理解他做了什么。”列夫·朗道在所有情况下的理解都相当独特，对普通人来说，不容易跟上他的推理思路。

1962年1月7日，列夫·朗道在从莫斯科到杜布纳的路上遭遇车祸。路面湿滑，他的车撞上了迎面驶来的卡车。车上其他人只受了轻微的割伤和擦伤，但列夫·朗道遭受了严重的骨折和内脏损伤。他被送往莫斯科的医院，在那里昏迷了六周。医生多次宣布他临床死亡。令人惊奇的是，列夫·朗道恢复了意识，尽管在许多方面他恢复了正常，但他再也无法进行创造性的工作。由于从未完全康复，他在车祸六年后因一次解除肠梗阻的大手术而去世。遗憾的是，这最后的六年是不断遭受痛苦和折磨的岁月。

我们在上面已经给出了一些关于列夫·朗道性格的引述。进一步的评论见[77]：-

他的个人品质有些令人费解。他对科学——以及关于科学——怀有炽热的真诚。他以热情和明显的学识吸引学生，但比大多数人更年长时仍保留着顽童的某些方面。他在批评时也可能激烈而无情。然而，认识他的人，从尼尔斯·玻尔到一位苏联人对他50岁生日的赞赏文章的作者，都同意在他尖锐的外表下有着人情的温暖。

彼得·卡皮察与他很熟，在[49]中写道：-

他毫不妥协的态度，是所有杰出科学家在工作中的典型特征，也延伸到了列夫·朗道的人际关系中。然而，熟悉他的人都知道，在唐突的背后是一个非常善良和富有同情心的人，总是愿意帮助那些被不公正对待的人。年轻时，列夫·朗道非常害羞，甚至回避社交；与人接触需要付出巨大努力。看来随着年龄增长，害羞有所减退，但列夫·朗道始终无法适应社交。正是列夫·朗道多方面的个性才华吸引人们接近他，而当他了解他们后，他们开始喜欢他，并在他的陪伴中找到极大的乐趣。物理问题研究所的每个人都喜爱朗道，他的离去让全体员工深感痛惜，尤其是他的学生，他们对他怀有特别深厚的感情。

列夫·朗道因其贡献获得了许多国际荣誉。他当选为丹麦皇家科学院（1951年）、Royal Netherlands Academy of Sciences（1956年）、英国物理学会（1959年）和伦敦皇家学会（1960年）的成员。同样在1960年，他当选为美国国家科学院和美国艺术与科学院的成员。除了1962年的诺贝尔奖外，他因低温物理学研究于1960年获得弗里茨·伦敦奖，同年获得马克斯·普朗克奖章。1962年，他当选为法国物理学会和纽约科学院的成员。他还获得了自己国家的荣誉：他当选为苏联科学院院士（1946年），三次获得国家奖（1946年、1949年、1953年），1962年获得列宁奖（与叶夫根尼·利夫希茨共同因《理论物理学教程》获奖），被授予社会主义劳动英雄称号（1953年），并两次获得列宁勋章。

Lev Landau's mother, Lyubov Veniaminovna Harkavi (1876-1941), had trained in medicine and she had undertaken work in physiology. She went on holiday to Switzerland with her friend Anna and met Anna's cousin, David Lvovich Landau (born 1866). Both Lyubov and David were Jewish and they fell in love [81]:-

[David Lvovich] was a composed and restrained person, and never raised his voice; [Lyubov] was a bundle of energy, quick-tempered and excitable. But opposites are often compatible and complement each other.

They were married in 1905 and went to live in Baku where David Lvovich worked. He was a petroleum engineer with the Black Sea and Caspian Sea Stock Company who worked at the oil fields in Baku on the Caspian Sea. He was well-off and owned a six-room apartment in the centre of the city. Their daughter Sonya was born on 8 August 1906, and their son Lyova (the subject of this biography, known as Lev) in January 1908. After the birth of her children, Lyubov Veniaminovna worked as a midwife and gynecologist then, from 1911, was a physician in a girls' high school. After doing war service in 1915-16, she worked as a teacher of natural sciences in the Baku Jewish High School. In addition to his work as an engineer, David Lvovich undertook research, wrote scientific papers and was a highly competent mathematician. He taught his son Lev mathematics from a young age. Both Sonya and Lev were very bright but very stubborn children.

A Jewish high school opened in Baku in September 1916 and the eight year old Lev began his schooling there. The school was designed to teach Russian, Hebrew, and Biblical Studies to Jewish children but also taught a full range of other subjects. Lev was brilliant in science and mathematics but only mediocre in Hebrew and Yiddish. His fellow pupils described him at this time:-

He was a quiet, shy boy, although the manner in which he related to his classmates, and even to his teachers, was somewhat condescending.

From his mother, Lev learnt French and German and quickly became fluent. He had piano lessons which he hated so he was soon allowed to stop these and study more mathematics. While Lev was at high school, the Russian Revolution took place. Lev was a staunch believer in Communist principles but, as we will see below, came to hate the Soviet leadership. His achievements at school were such that by the age of thirteen he had completed his secondary schooling and had the qualifications to enter university. Although calculus was not part of the school syllabus, Lev had studied this own topic his own and, later in life, would say that he could not remember a time when he was not proficient at differentiation and integration. His parents did not like the idea that he should begin his university studies a such a young age, and this was almost certainly a wise decision on their part. David Lvovich wanted his son to have a career in finance or administration so Lev was sent to Baku Economic Technical School for a year to delay his entry to university studies.

Landau was still only fourteen years old when he entered Baku University (later called the Kirov Azerbaijan State University) in 1922 and by this time he was already enthusiastic about mathematics, physics and chemistry. There he studied physics in the department of Mathematics and Physics but he also studied chemistry and, although he did not carry his studies of this topic any further through his university education, it remained one of his life-long interests. In 1924, after two years at Baku University, he moved to the Leningrad State University, graduating in 1927 [66]:-

In Leningrad - that main centre of Soviet physics at the time - he first made the acquaintance of genuine theoretical physics, which was then going through a turbulent period. He devoted himself to its study with all his youthful zeal and enthusiasm and worked so strenuously that often he became so exhausted that at night he could not sleep because he was still turning over formulas in his mind. Later he used to describe how at that time he was entranced by the incredible beauty of the general theory of relativity (sometimes he even would declare that such a rapture on first making one's acquaintance with this theory should in general be a characteristic of any born theoretical physicist). He also described the state of ecstasy to which he was brought on reading the articles by Heisenberg and Schrödinger signaling the birth of the new quantum mechanics. He said that he derived from them not only delight in the glamour of genuine science but also an acute realization of the power of the human genius, whose greatest triumph is that man is capable of apprehending things beyond the pale of his imagination.

In fact his first publication On the Theory of the Spectra of Diatomic Molecules appeared in print in 1926, while he was an eighteen year old undergraduate, and his second paper The Problem of Damping in Wave Mechanics appeared in the year he graduated, being his first paper on quantum theory. He continued research at the Leningrad Physico-Technical Institute.

In 1929, supported with a Rockefeller Foundation Fellowship, Landau set off for eighteen months of foreign travel, visiting Germany, Switzerland, Holland, England, Belgium, and Denmark. The visits which were most valuable to his research were those to Göttingen, Leipzig and particularly to Copenhagen where he worked in Niels Bohr's Institute for Theoretical Physics on three occasions, 8 April to 3 May 1930, from 20 September to 22 November 1930, and from 25 February to 19 March 1931 [66]:-

This scientific atmosphere, magnified by the charm of the personality of Bohr himself, decisively influenced Landau in forming his own view of physics.

From that time on he considered himself a pupil of Bohr and it was Bohr's influence that dictated the direction of Landau's future work [49]:-

... he also learned his teaching and training methods from Bohr.

The visits to Copenhagen also seemed to mark a change in Landau's character [77]:-

Landau, then and for some years afterwards, was an extremely provocative young man, who liked to shock.

During his trip abroad he went to Zürich where he worked from December 1930 to January 1931. There he collaborated with Rudolf Peierls (1907-1995) on relativistic quantum mechanics and their joint paper Quantum Electrodynamics in Configuration Space was published in 1931. Landau and Peierls discussed, in German, many topics including astrophysics. Peierls said in an interview in May 1977:-

He obviously was a very impressive character. I mean, his way of working was - if he saw a paper that interested him, he would glance at it to see what the problem was, and as a result he would sit down and solve the problem himself, and see whether his answer agreed with the paper.

While in Zürich he wrote the paper On the theory of stars but did not submit it for publication until he had returned to Leningrad [44]:-

Landau opened his four-page paper by arguing that theoretical astrophysicists were wrong to analyse stellar structure with the aid of mathematically convenient, but physically unrealistic assumptions. He illustrated this point by commenting on Edward Arthur Milne's ongoing campaign to overthrow Arthur Stanley Eddington's orthodox model of stars as gas spheres in which inward gravitational pressure is counteracted by outward radiation pressure. ... Believing that he had demonstrated the irrationality of "astrophysical methods," Landau averred that it was "reasonable to try to attack the problem of stellar structure [with the] methods of theoretical physics."

In 1931 Landau returned to Leningrad to work at the Physical Technical Institute, but in the following year he was appointed as head of the Theory Division of the Ukrainian Technical Institute in Kharkov and he was also appointed to the chair of theoretical physics at the Kharkov Institute of Mechanical Engineering. He moved to Kharkov to take up these posts, receiving a doctorate in Physical and Mathematical Sciences in 1934. One of his first projects in Kharkov was to organise an international conference on theoretical physics, and Niels Bohr attended the meeting [77]:-

Landau presided; Bohr opened the discussions on all papers ...

Soon afterward Landau was back in Copenhagen at a conference organised by Bohr [77]:-

... wearing a red coat and still provocative. During the next two years he produced original scientific papers at an average rate of one every six weeks and covered an astonishing range of subjects.

This extraordinary productivity was soon rewarded for, in addition to his other positions, in 1935 he received the title of professor and was made head of Physics at the Kharkov Gorky State University. Landau soon made his School in Kharkov the centre of theoretical physics in the USSR. In Kharkov, Landau met Konkordiya Drobantseva, a chemistry graduate known as Kora. She was a food technologist and from 1935 they lived together in a civil marriage which, some years later in 1946, they made formal when their son Igor was born. In Karkov, Landau had a talented student Evgenii Mikhailovich Lifshitz who began studying for his Ph.D. under him in 1933. Lifshitz was an exceptionally talented writer and Landau teamed up with him to create the ten volume 'Course of Theoretical Physics'. We give more details below.

In 1937 Landau went to Moscow to become Head of the Theory Division of the Physical Institute of the USSR Academy of Sciences. He worked on atomic collisions, astrophysics, low-temperature physics, atomic and nuclear physics, thermodynamics, quantum electrodynamics, kinetic theory of gases, quantum field theory, and plasma physics. The work he did on the theory to explain why liquid helium was super-fluid earned him the 1962 Nobel Prize for Physics. The citation states that he received the Nobel Prize for Physic:-

... for his pioneering theories for condensed matter, especially liquid helium.

Perhaps some details of the strange behaviour of liquid helium at a temperature just above absolute zero would be useful. It had been noted experimentally that if liquid helium at these low temperatures was placed in a beaker, then it climbed out of the beaker until the level outside was equal to that inside. Similarly liquid helium would climb into the beaker if the level outside exceeded that in the beaker. Landau devised a theory to explain such behaviour which was published in 1941. It predicted a new phenomenon, namely a temperature wave described a "second sound", and three years later experimental evidence produced in Moscow confirmed the existence of "second sound".

As we noted above, Landau believed in Communist principles, writing in 1935 that there were [35]:-

... unprecedented opportunities for the development of physics in our country, provided by the Party and the government.

However, he became increasingly unhappy with the way that Joseph Stalin was leading the country. Beginning in 1935, Stalin began a systematic elimination of his opponents in the 'Great Purge'. Soon it was leading members of his party, of the military, and important people from all walks of life who were being sent to prison, penal camps or work camps. Soon Landau was under investigation by the KGB who had received information from informers that he was making anti-government statements. It is not known whether he was the author of a pamphlet attacking the regime which was produced in 1938 but, if he wasn't, nevertheless it is clear that he supported and helped in its production. It begins as follows [35]:-

The great cause of the October Revolution is being despicably betrayed. The country is inundated with torrents of blood and filth. Millions of innocent people are being thrown into prisons and no-one can tell when his own turn will come. It is clear, comrades, that the Stalinist clique has carried out a fascist coup. Socialism has remained only on the pages of the habitually lying newspapers. In his rabid hatred of genuine socialism, Stalin is not different from Hitler and Mussolini.

On 28 April 1938, Landau was arrested and taken to Lubyanka prison. After two months of being forced to stand for seven hours a day and threatened with transfer to Lefortovo prison (which was much worse than Lubyanka prison) he wrote and signed a confession. One cannot take seriously a document produced under such circumstances but, in fact, it does seem to give a true account of Landau's views. He wrote later:-

I spent a year in prison and it was clear that I would be unable to live for even another half year.

Russian scientists tried to force the authorities to release him, with the leading physicist Peter Kapitza claiming he would stop his scientific work unless Landau was released. Kapitsa and Niels Bohr both wrote letters to Stalin insisting that Landau must be released. He was released in 1939 and reinstated as a research fellow at the Institute of Physical Problems.

Landau did some work on the Soviet atomic bomb in the second half of the 1940s. He certainly undertook mathematical calculations for work on the project and published a couple of papers which were outcomes of this work. It was not work he wanted to do but felt obliged to undertake it, particularly after his arrest and imprisonment some years before.

We mentioned above that one major contribution made by Landau was the writing of a number of outstanding textbooks and research monographs. His most famous book is his ten volume Course of Theoretical Physics written jointly with E M Lifshitz who was Landau's research student. They began work on this in the 1930's and the first part of the book is based on lecture notes. Lifshitz continued to work on the book after Landau's death and it was not completed until 1979. The work includes many of the results of Landau and Lifshitz's research over many years including the results of many jointly written research papers. The chapters of the book indicates the main topics of their joint research: Mechanics, theory of fields, quantum mechanics, quantum electrodynamics, classical statistical physics, quantum statistical physics, fluid mechanics, theory of elasticity, electrodynamics of continuous media, and physical kinetics.

See extracts from the Prefaces to Landau and Lifshitz: Course of Theoretical Physics at THIS LINK

See extracts from Reviews of Landau and Lifshitz: Course of Theoretical Physics at THIS LINK

Let us give some information about Landau's seminar. Before being accepted as a member of Landau's school, a candidate had to pass Landau's 'theoretical minimum'. This was a series of examinations that Landau set for which students had to spend a long time preparing. For example, Boris Ioffe, the author of [45] and [46], took almost two years to pass Landau's 'theoretical minimum'. Ioffe writes in [46] about Landau's seminar:-

To be Landau's disciple implied no privileges, only obligations. That's because anybody could have scientific discussions with Landau and get his advice. Moreover, only a few among those who passed Landau's minimum became his graduate students (I did not). Landau's students enjoyed full rights as participants of Landau's seminar. But, again, anyone could participate in his seminar, ask questions and make remarks. The obligations of the "full-right" participants were to prepare, in a regular way, in alphabetical order, review talks for the seminar. After each seminar Landau would take a recent issue of Physical Review (at that time it was not divided into sections) and point out to a speaker-to-be which papers he was supposed to report on at the seminar. As a rule, he would choose a dozen such papers from all branches of physics. ... The speaker not only had to review the paper, i.e. present its basic idea and final results, but was supposed to understand well how the results were obtained, present and explain to the audience all necessary formulae, including experimental techniques, and have his own opinion, as to whether or not the results were reliable.... The presentation of a theoretical report would proceed differently. A person, who wanted to present a theoretical investigation at the seminar (his own or from the literature) was first supposed to tell the story to Landau privately. If Landau agreed with the basic points of the work, then the talk at the seminar would be allowed. During the talk, Landau gave clarifying comments and quite often his explanation of the work was strongly different from that of the author. A hot discussion would then often follow. One could hear from Landau: "The author, in fact, did not understand what he did." Landau's understanding in all cases was quite original and for normal people it was not easy to follow his line of reasoning.

On 7 January 1962, Landau was involved in a car accident on the road from Moscow to Dubna. The road was slippery and his car hit a truck coming in the opposite direction. Others in his car suffered only minor cuts and bruises but Landau suffered serious fractures and injuries to his internal organs. He was taken to hospital in Moscow where he was unconscious for six weeks. Several times doctors declared him clinically dead. Remarkably Landau regained consciousness and although in many ways he returned to normal, he could never again perform creative work. Having never completely recovered, he died six years after his accident following a major operation to free an intestinal blockage. Sadly, these last six years were ones of constant suffering and pain.

We have given some quotes above concerning Landau's character. Further remarks are given in [77]:-

His personal qualities are something of an enigma. He had a flaming sincerity for - and about - science. He attracted students by his enthusiasm and evident knowledge, but to a greater age than most retained aspects of the enfant terrible. He could also be hot and merciless in criticism. Yet those who knew him, from Niels Bohr to the writer of a Soviet appreciation of his 50th birthday, agreed that there was human warmth below his sharpness.

Peter Kapitza, who knew him well, writes in [49]:-

His uncompromising attitudes, typical of all distinguished scientists in their work, extended to Landau's personal relationships. However, those who knew him well were aware that behind the abruptness was a very kind and responsive man, always ready to help people who had been unjustly wronged. In his youth Landau was very shy and even shunned society; any contact with people required great effort. It would appear that with age shyness waned but Landau was never able to adjust to society. It was only the many-sided talents of Landau's personality which drew people to him, and as he got to know them they would begin to like him and find great pleasure in his company. Everyone at the Institute of Physical Problems loved landau and his loss is sorely felt by the whole staff and in particular by his students, whose feelings towards him were especially profound.

Landau received many international honours for his contributions. He was elected to the Royal Danish Academy of Sciences (1951), The Royal Netherlands Academy of Sciences (1956), The British Physical Society (1959) and the Royal Society of London (1960). Also in 1960 he was elected to the U.S. National Academy of Sciences and the American Academy of Arts and Sciences. In addition to the Nobel Prize in 1962, he received the Fritz London Prize in 1960 for research in low-temperature physics and, in the same year, the Max Planck Medal. In 1962 he was elected to the French Physical Society and the New York Academy of Sciences. He also received honours from his own country: he was elected to the USSR Academy of Sciences (1946), received the State Prize three times (1946, 1949, 1953), received the Lenin Prize in 1962 (jointly with Evgenii Mikhailovich Lifshitz for the 'Course of Theoretical Physics'), was given the title Hero of Socialist Labour (1953) and twice awarded the Order of Lenin.