New forms of matter exist only at extremely low temperatures; when cooled billions of times lower than interstellar space, particles behave as waves and march in lockstep. Nobel laureate Wolfgang Ketterle will reveal this quantum world Wednesday, April 13, in a lecture titled "When Freezing Cold Is Not Cold Enough."

This free, public lecture will begin at 7:30 p.m. in Cornell's Schwartz Auditorium, Rockefeller Hall, and is one of three talks to be given by Ketterle, this year's Hans A. Bethe lecturer.

Einstein predicted these new forms of matter -- now called the Bose-Einstein condensate -- in 1925, but it wasn't until 1995 that they could be created in laboratories. Ketterle was awarded the Nobel Prize in physics in 2001 for his observation of Bose-Einstein condensation in a gas and the first realization of an atom laser.

"Cold atoms are a tool to study phenomena of condensed matter physics, at huge spatial magnification, at densities that are a billion times lower than ordinary materials," explains Ketterle, associate director of the Research Laboratory of Electronics and professor of physics at the Massachusetts Institute of Technology. Ketterle has studied superfluid atom pairs, which show behavior similar to electrons in superconducting materials.

Other talks by Ketterle in the Bethe Lecture series will be the Physics Colloquium "Superfluid Gases Near Absolute Zero Temperature," at 4:30 p.m. April 11 in Schwartz Auditorium, and the LASSP Seminar "Towards Quantum Magnetism With Ultracold Atoms," at 4 p.m. April 12 in 700 Clark Hall.

Born in Germany, Ketterle earned his master's degree at the Technical University of Munich and his Ph.D. in physics from the University of Munich. After postdoctoral work at MIT, Ketterle joined the faculty in 1993.

The Bethe Lectures, established by the Cornell Physics Department and the College of Arts and Sciences, honor Hans A. Bethe, Cornell professor of physics from 1936 until his death in 2005. Bethe won the Nobel Prize in physics in 1967 for his description of the nuclear processes that power the sun.

Linda Glaser is a staff writer for the College of Arts and Sciences.