Quantum Information Processing, Vol. 5, No. 1, February 2006 (© 2006) DOI: 10.1007/s11128-005-0006-x

In Memoriam: Thomas Beth

Thomas Beth, the internationally renowned computer scientist, mathematician, and visionary, lost his battle with cancer on August 17, 2005, at the age of 55. He left behind his wife, three daughters, and a wide family of friends, students, and colleagues, as well as a rich legacy of work in computer science, mathematics, and physics. ¨ His career started at the Universities of Gottingen and Erlangen¨ Nurnberg, where he received his diploma and PhD degrees in mathematics in 1973 and 1978, respectively. Thomas Beth received the Venia Legendi in computer science in 1984 and was Professor and Head of the Department of Computer Science and Statistics at the Royal Holloway College of the University of London in England. From 1985 until his untimely death, he was a chaired professor of computer science at the Universit¨at Karlsruhe (TH) in Germany where he served as the director of both the Institute for Algorithms and Cognitive Systems (IAKS) and the European Institute for System Security (E.I.S.S). Thomas Beth started his successful research career in the area of combinatorics. In his PhD thesis, he investigated resolutions of Steiner systems, and combinatorial designs became a recurring theme in his career. Although he was initially concerned with theoretical aspects of design theory, he gradually developed an interest in applications of designs in coding theory. His combinatorial work culminated in the monumental treatise on Design Theory that he wrote in 1985 jointly with Jungnickel and Lenz. After completing his PhD, his research interests broadened significantly. He started to investigate the algebraic aspects of the fast Fourier transform, where his main contribution included the design of fast Fourier transforms for solvable groups, and generalizations of the Hartley transform to algebraic discrete Fourier transforms. The results are documented in his monograph Verfahren der schnellen Fourier-Transformation. He also made efforts to convey the basic methodology to undergraduates in the textbook Mathematische Methoden der Systemtheorie: Fourieranalysis that he wrote jointly with Babovsky and Neunzert. He always understood his work on 1 1570-0755/06/0200-0001/0 © 2006 Springer Science+Business Media, Inc.

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fast Fourier transforms as an example of much broader algebraic concepts that allow the design of effcient algorithms, as well as the automatic translation of such algorithms into implementations. His enthusiasm for this idea is evident from the large number of PhD theses that emerged under his supervision, most of which can be understood as part of his IDEAS program for the algebraic engineering of algorithms. The implementations ranged from code generators to application specific integrated circuits to hybrid electrooptical computers. Cryptography was another research topic that he took up during the preparation of his habilitation. He organized a workshop on cryptography at Burg Feuerstein in 1982 which was the initial spark for a series of conferences now known as “Eurocrypt”. He also organized many workshops at the well-known German conference centers in Oberwolfach and Dagstuhl and helped to popularize cryptographic methods in Germany. He investigated vocoders for severely bandlimited telephone networks in his joint book Kryptographie with Heß and Wirl. One of his first accomplishments as Professor in Karlsruhe was his founding of the European Institute for System Security (E.I.S.S.), which had a vibrant visitor program. At E.I.S.S. smart card technology as well as internet firewalls were developed in the early 90s, at a very early stage. Also the E.I.S.S. was and still is an active think tank for public-key algorithms, provably secure cryptographic systems, and cryptanalysis of systems. The interests of Thomas Beth were not limited by the boundaries of traditional research disciplines. Following his passion for medicine that he developed during his undergraduate days, he founded—with colleagues from Heidelberg and Karlsruhe—a center for computer-aided surgery. He started to pursue the dream of better understanding the human body and was seeking tools that allow a better integration of humans in their environment. Thomas Beth and his colleagues from Karlsruhe embarked on the journey to found a new scientific discipline, called Anthropomatics, to realize this vision. Always ready to think outside the box of science, he also interacted with such diverse areas as philosophy, metaphysics, and arts. He would find baffling cross connections between these areas and often was able to link them back to beautiful mathematics. An example of this is the installation “Laser Movie” which is an interactive hologram realizing a shutter-less movie by a diffractive optical element. Together ¨ Muller-Quade ¨ with Jorn and Michael Schmid, Thomas Beth was co-cre¨ ator of this marvelous piece of art which is exhibited in the Zentrum fur Kunst und Medientechnologie (ZKM) Karlsruhe. In the past decade, Thomas Beth was particularly compassionate about quantum computing. He immediately recognized the beauty of this subject and began promoting it. As early as 1995 he offered a course on

In Memoriam: Thomas Beth

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quantum computing, which seemed outrageous at the time. The course was an eclectic mix of computer science and quantum physics, always at the frontier of this ever-so-fast growing new research field. Sometimes his lectures were so spontaneous that his secretary would bring him a fax of a colleague’s latest preprint during the lecture which he then discussed with students who greatly enjoyed the show he would always put on for them. After 1995, Thomas Beth started to offer courses and seminars on quantum computing, quantum algorithms, and quantum error-correcting codes on a regular basis. His enthusiasm for the subject was contagious and soon he was heading one of the largest research groups in quantum computing in Germany. One of his great services to the scientific community were the numerous conferences and workshops which he organized. In 1993, when the emerging field of quantum information was still in its infancy, he and Gilles Brassard realized its importance and organized a seminar at the International Conference and Research Center, Schloss Dagstuhl, on “Quantum Cryptography and Quantum Information Theory”. They again brought together leading scientists in this area at the follow-up Dagstuhl seminar on “Quantum Algorithms” which took place in 1998. During the years between 1995 and 2000 Thomas Beth was part of the extensive interdisciplinary international research activity on quantum computing which was happening at the Institute for Scientific Interchange (ISI) at Torino, Italy. From 1998 until his death he was Division Director for Quantum Information and Computation of the ISI. The involvement with the ISI led to a successful joint research project on the European level which was carried out under his coordination. Partners of this Fifth Framework Programme project were the ISI, the IAKS, and the University of London at Royal Holloway. The ISI is famous for the legendary quantum summer workshops at the Villa Gualino which is located in the hills overlooking the city of Torino. Between 1995 and 2000 every summer the community would gather here to exchange the latest research and to mingle between lecture hall, cafeteria, and by the copy machine overloaded with piles of preprints. Thomas Beth loved to interact with researchers from other disciplines and he realized very early on that computer scientists can learn a lot from physicists and vice versa. Hence, these summer workshops were tailor-made for him and he followed the talks with utmost interest and a discerning mind. The days at the Institute for Scientific Interchange—which overlooks the city of Torino, the river Po, and the peaks and valleys of the Alps in the distance—were great inspirations for his own work. He always shared these days of productivity with his students and would interrupt work sessions only for excessive jogging tours through

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the hills; those lucky enough to be able to follow the flow of his thoughts quite often did not match his stamina which allowed him to run while still working out the Bratteli diagram of the irreducible representations of some non-abelian groups. Working with Thomas Beth was quite an experience. On a typical day, he would start working at home, faxing corrections to manuscripts and theses to his co-authors and students. Coming to university, he would first swim one kilometer during the lunch hour, and afterwards would work and brainstorm with his students and postdocs until late into the night. The range of topics that he would cover during such a session was just amazing. After discussing problems in diffractive optics with one student, he would try to solve a problem in computational algebra, then suggest some solutions to a medical image processing problem, go on to prove some results concerning quantum circuits, and all this within an hour. Thomas Beth was widely renowned for his elating lectures, and so he was not only invited speaker at many occasions, but also visiting professor to King’s College, London, England, Universit¨at Innsbruck, Austria, the University of Wollongong, Australia, and the University of California, Santa Barbara, USA. He was author, co-author, and editor of several books and proceedings in the Lecture Notes in Computer Science series. He was editor of the journals Applicable Algebra in Engineering, Communication and Computing; Designs, Codes and Cryptography; International Journal of Information and Computer Security; Journal of Computer Security; Journal of Cryptology; Surveys of Mathematics for Industry, and this journal. He published more than 250 research papers in and around the essential areas of computer science, mathematics and electrical engineering, and quantum computing. Many interesting papers will never be written, many inspiring thoughts will never be expressed. With Thomas Beth the scientific community has lost a researcher of great character, integrity, and vision. Markus Grassl ¨ Informatik, Universit¨at Karlsruhe, Fakult¨at fur Karlsruhe, Germany. Andreas Klappenecker Department of Computer Science, Texas A&M University, College Station, TX, USA. E-mail: [email protected] ¨ Martin Rotteler NEC Laboratories America, Princeton, NJ, USA.