Biography of Karl Hess BIOGRAPHY

hysicists have strived for centu- back,’’ Hess said. His persistence paid ries to understand the behavior off; in 1977, the University of Illinois of , information crucial offered him a visiting associate profes- P for explaining electricity and the sorship. physical properties of all materials. Al- though electrons are exponentially too Supercomputers, Super small to see, researchers have developed After Hess returned to Illinois, he a variety of techniques for simulating worked to improve the efficiency of electronic nature and movement with charge-coupled devices, computer models. A leader in this field chips that record images in video cam- is Karl Hess, professor of electrical and eras. However, craving more basic study, computer engineering at the University he soon teamed up with engineering of Illinois, Urbana. professor Ben Streetman, now at the With his colleagues, Hess has devel- University of Texas at Austin, to investi- oped numerous tools for dis- gate a broader class of semiconductor cerning the behavior of electrons in materials and devices. The two scientists solids, semiconductor lasers, and other developed the concept of ‘‘real space devices. His work has earned him many Karl Hess. transfer’’ (4), which explains the perfor- grants and accolades, including the rare mance of certain high-frequency transis- dual election to both the National Acad- fessor at the University of Vienna. A tors. Streetman also mentored Hess on emy of Engineering (2001) and the Na- the politics of American university life. tional Academy of Sciences (2003). In year later, he met University of Illinois professor , who was on a His advice helped Hess land a tenured his Inaugural Article (1), published in professorship of electrical and computer lecture tour throughout Europe. A giant MATHEMATICS this issue of PNAS, Hess and mathema- engineering at the University of Illinois tician Walter Philipp discuss certain lim- of electrical engineering, Bardeen coin- vented the transistor in 1947 and was a in 1980, a position he still holds. itations of Bell’s Theorem, a current At about that time, Hess’ expertise cornerstone for quantum theory. The pioneer in the field of superconductiv- ity: the complete disappearance of elec- in semiconductor research caught the authors’ conclusions suggest completely attention of the United States Naval new interpretations of quantum mechan- trical resistance in some substances, especially at very low temperatures. Research Laboratory (NRL), which ics and may help foster the development assigned him confidential military re- of quantum computers. When Bardeen offered Hess a favor in return for some translating work, Hess search. His work with NRL, as well as Combining Science and Technology asked for help finding a postdoctoral his consequent research for the Office of Naval Research and the Army Re- As a young boy in Vienna, , Hess fellowship in the United States. Bardeen didn’t let Hess down. After search Office, was invaluable in shaping became fascinated with electricity. Dur- his future research interests. Although ing his elementary years, he came across receiving a Fulbright scholarship in 1973, Hess left Vienna with his wife and unable to elaborate on the specifics, a book on 19th century inventions in his Hess said, ‘‘It gave me an overview of father’s library. ‘‘I read the book in- two children to join Bardeen at the University of Illinois. Hess soon met what was going on in semiconductor tently, especially the section on electric- research in the United States.’’ ity,’’ he said. Hess continually tinkered Chih-Tang Sah, who was also at the University of Illinois and is coinventor In his nonclassified r