Gallager in Action
I read the article “Code Quest” in the September/October Technology Review with much interest. In 1961 I was a graduate student in the MIT School of Industrial Management. Previously I had been a math major and then a computer programmer for several years, and I wanted to broaden my business background. Although not required to do so, I took a course in information theory taught by Professor Gallager in the electrical-engineering department. The course content was very interesting and, for me anyway, quite difficult. At midterm he passed out a take-home exam that I sweated over. A few questions were unintelligible to me, but finally I estimated that I had answered about 80 percent correctly and that would have to suffice. When the exam was passed back, I had scored in the low 30s. I was devastated and immediately scheduled an appointment. At the beginning of the meeting, Professor Gallager smiled at me and said, “You’re not an engineer, are you?” After a pleasant discussion, he advised me not to be concerned about my final grade. That same year I also participated in a seminar on the evaluation of investments. In addition to the handful of graduate students, Professor Claude Shannon and his wife attended regularly. We students all knew who he was, and at first it made us nervous. But he never caused anyone a bad moment. He was just auditing the course.
Sydney P. Levine, SM ‘62
New York, New York

A Surprise at the LHC
In the last issue, Markus Klute described the excitement that greeted the first proton collisions at record energies at CERN’s Large Hadron Collider in March (“Smashing Protons in the Cathedrals of Science,” September/October 2010). Now the LHC and the particle detectors are working to detect trillions of proton collisions over the next year. Already the great performance of the Compact Muon Solenoid (CMS), on which the MIT team collaborates with 3,000 other physicists from many countries, has allowed us to observe some unexpected effects.
One such surprise arose in the MIT heavy-ion group’s recent search for “high-multiplicity” collisions, which make up only 0.0006 percent of all collisions. We were hoping to probe the well-known strong interaction at high density, where it might reveal some new tricks. Our patience was rewarded: the high-multiplicity events showed a previously unknown correlation between particles. We found that sometimes the path of a particle close to one edge of our detector was mirrored by a “partner” particle at the opposite end of the detector. This “long-range” correlation is remarkable, as the two partners fly away from the collision in opposite directions at close to the speed of light. Since information can’t travel faster than the speed of light, causality implies that they communicated their trajectories by some process when they were still close together. But current models can’t explain what causes such correlations.
The correlation effect was presented to a packed auditorium at CERN in late September. Almost immediately, a number of theoretical papers appeared, each proposing a different explanation. More information from proton collisions and lead collisions is being collected by the CMS, and with hard work, the right intuition, and a bit of good luck, we’ll soon understand what nature was trying to tell us with this little surprise!
Gunther Roland
Associate professor of physics
Cambridge, Massachusetts

Rethinking Tenure
I was disappointed to learn from a June 10 story in the Tech that Eric Hudson, an assistant professor of physics, was denied tenure. Professor Hudson has enjoyed excellent relationships with his faculty colleagues and received the Baker Award for Excellence in Undergraduate Teaching for instructing 8.02. The Baker Award is called the “kiss of death” because professors who devote time to course preparation must give up time that could otherwise have been spent on research–and MIT awards tenure for outstanding research and competent teaching. The denial of tenure to Professor Hudson is not only a disservice to him. It is also a slap in the face to MIT undergraduates, because it shows how little the Institute values their education. Many more modest universities have an alternative track for awarding tenure on the basis of exceptional achievement as a teacher. MIT should modify its tenure criteria by adding this track. To initiate this change, the Academic Council, chaired by President Susan Hockfield, should overturn the decision against Professor Hudson and award him tenure. Perhaps one day MIT will augment its reputation for world-class research with a reputation for a genuine commitment to excellence in education. By granting tenure to exceptional teachers, MIT will graduate more loyal alumni, many of whom will conduct leading-edge research.
Theodore J. Sheskin ‘62
Lakewood, Ohio

Editor’s note: Eric Hudson is currently a senior lecturer in physics at MIT. In September, the Tech reported that he was initially asked to stay on for a year; following a student petition, the offer was extended to three years. He is teaching 8.01 this fall and doing research at Harvard while looking for a new job.

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