序　朱棣文——捕捉原子的诺贝尔奖得主

我第一次见到朱棣文是在1970年，当时他作为加州大学伯克利分校物理系一年级的研究生，加入了我的实验室，选修了“热力学”和“统计力学”的课题。时间不长，我就发现他非常的不一般：反应机敏、有才气、精力充沛，并且为人友善。他卓越的表现，使他成为班里最出色的学生。他会提出很多的问题，我们也经常进行讨论，很快我们就成为伙伴。

后来的一些时间，朱棣文问我是否可以同意他成为我的助理研究生。在那时，我快要完成我的一些研究课题，并且很渴望去寻找一些新的课题，但是我不能确定新的研究方向。以我的办事准则，我是不太想让一个新的研究生加入的，但从另外一个角度，如上所述我怎么能拒绝像朱棣文这样出色的学生呢？因此，我同意接受他并且我们开始一起工作，先从一个课题，再到另外一个课题。

在那些年代里，我们难免遇到挫折和失败，我感到有才气的朱棣文会提出比我更好的建议，来解决这些问题。

现在已过去30多年了，朱棣文作为一个物理学的研究员和教授，他获得了巨大的成功，获得了崇高的荣誉，获得了诺贝尔奖，最近又被聘为劳伦斯伯克利国家实验室主任。

他能做出如此优异的成绩，我以前是没有想到的，但是，他做到了。然而，我作为他的导师，我仍然感到无比的自豪和骄傲，出于这个原因，非常高兴为李剑君和曹慧所写的《朱棣文》写序，以此短序来表达我对他们努力将朱棣文介绍给广大中国的读者工作的敬意。

欧根·康明斯(Eugene D. Commins)

注：欧根·康明斯是加州大学物理系终身教授，世界实验物理大师。

To the biegraplievs of Steven Clam:

I first met Steven Chu in 1970, when he attended my lectures in thermodynamics and statistical mechanics as a first-year graduate student in physics at the University of California,Berkeley. It did not take long for me to realize that he was very unusual: quick, brilliant,energetic, and outgoing, he distinguished himself as the best student in that class. He asked many questions, we entered into many discussions, and soon we became well-acquainted.

After some time, Steven asked me if I would accept him as a research student. At that moment, I had nearly completed several research problems, and was anxious to try something new; but I was unsure of what that new direction should be. Thus as a matter of principle, I was reluctant to take on a new research student just then; on the other hand how could I forego the opportunity with someone so outstanding as Steven? So, I agreed to accept him and we started to work together, first on one problem, then on another. For several years, we encountered only frustration and failure, and I began to feel that the very brilliant Steven Chu surely deserved a better advisor than me.　However, he remained faithful and determined, and eventually we found a fruitful and interesting path to pursue together-parity nonconservation in atoms.

Now more than 30 years have past, and Steven Chu has achieved great honor and distinction as a research physicist and professor, as a Nobel Prize winner, and most recently as Director of the Lawrence Berkeley National Laboratory. I have no right to claim any credit for his many brilliant accomplishments, most of which I never imagined could be possible before he actually did them. Still, as his teacher, I may perhaps be forgiven for feeling very proud of him.For this reason I am very glad that Li Jianjun and Cao Hui have written this biography of Steven Chu in an effort to introduce him to Chinese readers, and I am honored to contribute this short preface to their work.