王明贞与乌伦贝克:布朗运动的奠基理论 99xcs.com

【作者简介】冯达旋、明尼苏达大学理论物理学博士学位。曾担任德雷塞尔大学 M. Russell Wehr 讲席教授、美国物理学会会士(APS Fellow), 美国 NSF 理论物理主任、德克萨斯大学达拉斯分校研究副校长、成功及清华大学(台湾)资深副校长。

明贞与乌伦贝克:布朗运动的奠基理论

冯达旋

November 2, 2025

久久小常识(www.99xcs.com)™

1968至1972年间,我在明尼苏达大学攻读理论物理博士。由于我的论文涉及使用蒙特卡洛方法计算一个六维积分,随机运动逐渐成为我研究之外的一个兴趣点。

顺便说一句,今天的物理学家可能会觉得我疯了——六维积分算什么难题?甚至我的手机可能几秒钟就能算出来。但在上世纪六七十年代,所谓最快的计算机——CDC-6600 或 CDC-7600——完成这项计算仍需耗费大量时间。因此,我的导师 Ben Bayman 和我决定尝试用随机数生成来完成计算。我们做到了,并成功发表了相关论文(附于此)。

在研究过程中,我对“随机性”这一概念产生了浓厚兴趣,自然而然地走向了粒子运动中的随机游走领域。

简而言之,这种科学上的好奇心和一点点探索,很快引导我发现了该领域最早的一篇论文——或许就是第一篇——发表于1945年《现代物理评论》。作者是王明贞(Ming Chen Wang)与乌伦贝克(G. E. Uhlenbeck)。

久久小常识(www.99xcs.com)™

除了这项研究本身与我对“随机性”的兴趣高度契合,我还被两件事深深吸引:

首先,乌伦贝克是世界知名的物理学家,曾共同提出电子等基本粒子的自旋概念(但未获诺贝尔奖认可)。

其次,在我物理研究的早期阶段,中国对我而言几乎是一个“黑洞”。因此,看到作者之一是华人,自然让我倍感亲切。

几十年过去了,尽管我的研究早已远离“随机性”领域,但我始终好奇王明贞是谁。自1982年起,我每次访问中国,都会向朋友打听她的来历,但始终没有明确答案。

直到昨天,在 Facebook 上看到一篇文章,终于揭开了谜底。

(https://www.facebook.com/feng.da.xuan)

我终于知道王明贞是谁了。令人遗憾的是,我也在此了解到她的一生充满艰辛,但她始终忠于自己的物理学事业,直到生命的最后一刻。

我希望将我所写的这些文字,作为献给王明贞的纪念——她是物理学中“随机理论”的开创者之一,是值得我们永远铭记的科学先驱。

人物传记

norpstoSdeuhm79u3c42luimh91hu9m2c31t36c0ch7190ca3th3l10i50ft ·

「中國居禮夫人」的傳奇,出身超牛家庭,手寫雷達機密,毅然回國晚年曲折

出身蘇州百年望族,卻一生坎坷無兒無女,晚年更身陷囹圄六年 —— 她是世界級統計物理學家,有「中國居禮夫人」之稱的王明貞。1906 年,她誕生於「科技豪門」:遠祖王鏊是明朝戶部尚書,祖父王頌蔚是蔡元培老師,祖母謝長達創辦振華女中,家族先後出六位院士;父親王季同是中國首位在國際數學期刊發表論文的學者,十二位兄弟姐妹中六人考入清華。

雖出身名門,王明貞求學路卻布滿荊棘。求學時穿表哥舊雨鞋遭嘲笑,她以全科「A」反擊;生母早逝,繼母逼她早婚,她拼死爭取才入讀金陵女大,大二便修完大三物理課。因老師憑印象打「B」,她轉學燕京大學;1928 年考上美國密西根大學,因繼母不資助作罷;1932 年庚子留學考試優異,又因主考官「女孩學物理何用」錯失機會,最後靠金陵女大校長吳貽芳推薦,才獲全額獎學金赴美的。

在異國,她是班上唯一女生與外國人,首次電力學考試拿 100 分(第二名 36 分),奪全美學生最高榮譽「金鑰匙獎」。博士期間,與導師推導的「王 - 烏倫貝克方程」,至今被引用數千次;進入麻省理工學院雷達實驗室,參與編寫的雷達系統,獲諾貝爾獎得主拉比盛讚「繼《舊約》後最偉大作品」。

朝鮮戰爭爆發後,她放棄美國優渥生活回國。美國移民局威脅判刑,她仍不動搖,與丈夫俞啟忠歷經險阻,1955 年終歸國,49 歲成為清華首位女教授。她無子女,視學生如己出,主動將二級教授降為三級,只因「錢學森也才三級」。

後來她被關秦城監獄六年,每日在水泥地上默寫麥克斯韋方程組保持清醒。出獄後,她回到清華執教至 90 歲,住簡樸小屋,晚年僅一次麻煩人,是打聽遺體捐贈。2010 年,她遵遺願將遺體捐醫學研究。她的一生,在安逸與險阻間選險阻,榮耀與樸素間選樸素,以清澈理性與不動定力,將命運砂礫化為照亮時代的珍珠。

Wang and Uhlenbeck: A Ground Breaking Theory of Brownian Motion

Da Hsuan Feng

November 2, 2025

Between 1968-72, when I was a graduate student in theoretical physics at the University of Minnesota, because of my thesis work of utilizing the Monte-Carlo method of integrating a six-dimensional integration, random motion became one of my side interests.

By the way, for physicists today, you must think I am nuts that integrating a six-dimensional integration is absolutely no big-deal. Even my cell phone probably could have done that in no time. However, in the late 60’s and early 70’s, the so-called fastest computer then, known as CDC-6600 or CDC-7600, would have taken way way too long to carry out the calculations! So, my thesis advisor Ben Bayman and I thought that perhaps using random number generation could allow us to carry out the calculation. We did that, and it was successful. The published paper on this work was enclosed herewith.

Well, like everything else, during my research of doing the work, I became fascinated by the concept of “randomness”, which naturally led me to the area of random-walk in particle motion.

To make a long story short, this sort of personal scientific inquisition and a little research into the field quickly led me to one of the first, if not the first of the subject in a paper published by two people in the Reviews of Modern Physics in 1945. The authors were Ming Chen Wang and G. E. Uhlenbeck.

久久小常识(www.99xcs.com)™

Besides the fact the science was relevant to my curiosity on anything that is random at the time, I was also instantly drawn to it for another two reasons.

First, Uhlenbeck was already a world-renowned physicist who co-developed the concept of spin of elementary particles such as electrons (but was omitted in the Nobel prize for the work),

Second, at that time in my early days of physics research, China was de facto a blackhole to me, and therefore seeing one of the authors is a Chinese naturally drew me towards the work.

Fast forward to the next several decades, while my physics research has gone way beyond anything that is related to “randomness”, I was always curious to find out who Wang is.Indeed, each time I visited China since 1982, I always asked friends who Ming Chen Wang was, and so far during my many visits to China no one gave me a clear direction.

Yesterday, in a Facebook (https://www.facebook.com/feng.da.xuan) article from someone, this cleared up.

I finally found out who Wang was. Unfortunately, here I learned that she had a difficult life, but remained loyal to her profession as a physicist until the end of her life.

I want to use what I have written her as a tribute to Ming Chen Wang, the pioneer of random theory in physics