Scientific contributions of Leo Khachiyan (a short overview)

On April 29, 2005, Leo Khachiyan passed away with tragic suddenness in the middle of his scientific career. He became famous for his polynomial time algorithm for linear programming (LP)[L. Khachiyan, A polynomial algorithm in linear programming, Soviet Math. Doklady 20 (1) (1979) 191-194; L. Khachiyan, Polynomial algorithms for linear programming, USSR Comp. Math. and Math. Phys. 20 (2) (1980) 51-68]. However, he contributed fundamentally to several other areas, as well. In this introductory paper, we would like to recall briefly his main contributions, and provide a complete (up to our best knowledge) list of his publications.     

Einstein as Engineer:The Case of the Little Machine

I first discuss Albert Einstein’s practical and educational background in engineering and then his invention of his “little machine,” an electrostatic induction machine, while working in the Patent Office in Bern, Switzerland, between 1902 and 1909. He believed that it could be used as a voltage or potential multiplier in experiments to test his new theory of Brownian motion of 1905. I then discuss Einstein’s search for collaborators to produce it and the work that his friends Conrad and Paul Habicht, in particular, did in designing and testing it. Although the initial response to it was promising, it never became a success after Paul Habicht manufactured a few specimens of it beginning in 1912.Today only three specimens are known to exist; these are preserved at the Zürcher Hochschule Winterthur, Switzerland, in the Physics Institute of the University of Tübingen, Germany, and in the Museum Boerhaave in Leiden,The Netherlands.     

1998年11月17日狮子座流星雨的次声观测

采用三台ＣＳＨ－１型次声接收器,在北京昌平区布置了一个次声测量三点阵,并观测到１９９８年１１月１７日狮子座流星雨产生的次声波Ｐ－ｔ曲线和波速波向图,借助快速富立叶变换,分析Ｐ－ｔ曲线的波形得到次声的三维动态谱,频谱分析结果表明,（１）各流星产生的次声波大都很短暂,持续时间在１－５分钟内;（２）流星次声波的周期都在４０－４０８秒内,少数在１－４８０秒内;（３）在１１月１７日１９：２１－２０：４１期间     

American Physicists, Nuclear Weapons in World War II, and Social Responsibility

Social responsibility in science has a centuries-long history, but it was such a minor thread that most scientists were unaware of the concept. Even toward the conclusion of the Manhattan Project, which produced the first nuclear weapons, only a handful of its participants had some reservations about use of a weapon of mass destruction. But the explosions over Hiroshima and Nagasaki not only made society more aware of the importance of science, they made scientists more aware of their responsibility to society. I describe the development of the concept of social responsibility and its appearance among American scientists both before and after the end of World War II.Expanded version of a talk in Hiroshima, Japan,August 10, 2003.Lawrence Badash is Professor Emeritus of History of Science at the University of California, Santa Barbara.     

A note on depth-first derivations

It is shown that the depth-first Szilard language associated with the depth-first derivations of a context-free grammar is ans-language.This work was supported by the Academy of Finland.     

E.U. Condon: Science, Religion, and the Politics of World Peace

I set forth and discuss E.U. Condon’s views on science and society, focusing specifically on Condon’s views on science and religion, science and government, and the necessity for world peace. Even disregarding his contributions to theoretical physics, Condon proves an interesting case study for several reasons. He had extensive experience in academia, industry, and government, and was a scientist who easily crossed the insider-outsider divide between scientists in Cold War America. Moreover, Condon was a person of the Progressive Left advocating World Government as necessary for peace and warning of the dangers of the militarization of American society as well as of science itself. Known for being outspoken, he became an inviting target for the forces of anticommunism in Cold War America. In March 1948, the House Un-American Activities Committee charged that Condon was “one of the weakest links in our atomic security.” Michael A. Day is Professor of Physics at Lebanon Valley College. He holds doctorates in both physics and philosophy.