In memory of George Marx
I read with great sorrow about the demise of George Marx (CERN Courier April 2003 p33). I first met him in 1969 when, as a UNESCO adviser, he visited the Punjab University in Lahore, Pakistan, for about three weeks and delivered a series of lectures on CP violation in the Physics Department. He was an excellent speaker and knew the art of communicating his ideas to the audience. His deep understanding of the subject was commendable and he would answer questions to the entire satisfaction of the listeners. He was a witty person, we always enjoyed his comments during conversation, and he was also very keen to visit historical places in Pakistan.
During his stay he also prepared a detailed proposal for the establishment of a centre of excellence in the Punjab University. The centre was ultimately established a few years later but, owing to the local situation, in the field of solid-state physics.
We will always remember George as a sincere friend, an excellent teacher and a great scholar. Without doubt he was one of those physicists by whose names Hungary is recognized in the international physics community.
Mohammad Saleem, c/o Physics Department, Punjab University, Lahore, Pakistan.
The universe as cellular automaton
In his book A New Kind of Science, reviewed by Luis-Alvarez Gaume (CERN Courier January/February 2003 p55), Stephen Wolfram presents certain ideas as if they were his own, without giving proper credit.
Konrad Zuse was the first to suggest that the physical universe is running on a cellular automaton (CA). His first paper on this topic dates back to 1967 (K Zuse 1967 Rechnender Raum Elektronische Datenverarbeitung 8 336-344). Zuse's book on CA-based universes came out two years later (Rechnender Raum, Schriften zur Datenverarbeitung, Band 1, Friedrich Vieweg & Sohn, Braunschweig, 1969; translated into English in Calculating Space, MIT Technical Translation AZT-70-164-GEMIT, 1970). Ed Fredkin, who initiated the translation of Zuse's book, later also published related ideas.
Wolfram misrepresents Zuse's work, mentioning him in a single sentence claiming that Zuse said the universe "could be a continuous CA", as if something essential was missing in Zuse's work. Zuse in fact suggested that the universe is computed by a discrete computer or CA. Wolfram's book does not add anything substantial to Zuse's ideas, and does not make any predictions that go beyond Zuse's.
On page 486 of his book, Wolfram tries to distance himself from Zuse by writing that "the universe might not work like a CA...but instead like a mobile automaton or Turing machine". The first paper to suggest this was in fact by J Schmidhuber, "A Computer Scientist's View of Life, the Universe, and Everything" (in Lecture Notes in Computer Science, pp201-208, Springer, 1997). This essay also described what is probably the simplest algorithm for our universe, namely the one that computes all possible universe histories with all possible computable laws. This approach is echoed in Wolfram's chapter 9 section on multiway systems, without reference.
(I am trying to convince myself that this embarrassing kind of self-promotion is at least weakly justified as a reaction to Wolfram's own self-congratulatory style.)
For Zuse's 1967 book see www.idsia.ch/~juergen/digitalphysics.html, for the 1997 paper see www.idsia.ch/~juergen/ computeruniverse.html.
Juergen Schmidhuber, IDSIA, Lugano, Switzerland.
The 2003 CERN School of Computing, organized by CERN in collaboration with the Institut für Hochenergiephysik (HEPHY), Österreichische Akademie der Wissenschaften, Vienna and the Donau Universität, Krems an der Donau, will be held on 24 August - 6 September in Krems an der Donau, Austria. It is aimed at postgraduate students and researchers with a few years' experience in particle physics, computing or related fields. Special themes this year are algorithms, grid technologies and software technologies. More information is available at www.cern.ch/CSC/.
The 10th Euro Summer School on Exotic Beams will be held in Valencia on 4-12 September. It is intended for PhD students and young postdocs who are interested in the field of nuclear physics with radioactive beams. Theoretical talks will cover symmetries in N~Z nuclei and shell-model applications in nuclear physics and astrophysics, while experimental talks will review studies of the most exotic species. A special topic will be the transmutation of nuclear waste. For more information see http://ific.uv.es/~euschool/index.htm.
The 5th Workshop on Small-x and Diffractive Physics will be held at Fermilab on 17-20 September. The workshop will review theoretical and experimental progress in the physics of diffraction and rapidity gaps, and the small-x properties of the proton. New data are expected from the Tevatron, HERA, RHIC, etc and LHC and other plans will be reviewed. Progress in theory and phenomenology will be presented. For further details see http://conferences.fnal.gov/smallx/index.html.