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Science Friday > Archives > 2001 > January > January 19, 2001:

Hour Two: Stopping Light / Amir Aczel on Infinity

Earlier this week, two groups of scientists working independently announced that they had managed to stop light in its tracks. Their success may have applications in information storage, quantum computing, and other high-tech fields.

Last year, Harvard researchers reported slowing the speed of light down to about 38 miles an hour by sending it through a cloud of super-chilled sodium atoms in a state of matter called a Bose-Einstein condensate. The speed of light in a vacuum is 186,171 miles per second.

Now, those researchers and a group at the Harvard-Smithsonian Center for Astrophysics have managed to take the work one step further, using the interaction between two laser beams, chilled atomic vapor (sodium in one case, rubidium in the other), and a magnetic field to stop light, hold it inside the vapor, and then release it later. We'll talk about how they did it, and what it means.

We'll also tackle another mind-bending subject: infinity. Philosophers, theologians, and mathematicians have tried for years to work with the idea of the infinite. The Greek philosopher Xeno is particularly known for his paradoxes involving the problems of thinking in terms of the infinite. In this hour, we'll talk with Amir Aczel, author of "The Mystery of the Aleph," a book on the search for infinity (as well as author of Fermat's Last Theorem and God's Equation). Call in with your thoughts and comments at 1-800-989-8255, and share your opinions online in our Listeners' Lounge (registration required)

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Guests:
Seth Lloyd
Assistant Professor, Mechanical Engineering
Massachusetts Institute of Technology
Cambridge, Massachusetts

Amir Aczel
Author, "The Mystery of the Aleph: Mathematics, the Kabbalah, and the Search for Infinity"
Professor, Mathematics
Bentley College
Waltham, Massachusetts

Books/Articles Discussed:

"The Mystery of the Aleph: Mathematics, the Kabbalah, and the Human Mind" by Amir D. Aczel. Four Walls Eight Windows, 2000. "Storage of Light in Atomic Vapor." D.F. Phillips, A. Fleischauer, A. Mair, R. L Walsworth and M.D. Lukin. Physical Review Letters, 29 January 2001. "Observation of coherent optical information storage in an atomic medium using halted light pulses." C. Liu, Z. Dutton, C.H. Behroozi, L. V. Hau. Nature, 25 January 2001. (find more SciFri books here)

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Related Links:
NY Times (free reg. required) Scientists Bring Light to Full Stop, Hold It, Then Send It on Its Way
Boston Globe Online: Harvard scientists say they've stopped light
NY Times (free reg. required) In a Major Breakthrough, Danish Physicist Slows the Speed of Light
AIP Focus: How to Catch a Moonbeam
Math Forum: Ask Dr. Math: FAQ: Large Numbers and Infinity
Mega-Mathematics: Welcome to the Hotel Infinity!
Michigan Math Scholars: Infinity

This segment produced by: Karin Vergoth
Web Producer: Charles Bergquist