David Wineland, the 2012 Nobel laureate in physics and a member of the National Institute of Standards and Technology (NIST), presented the Physics Department's 2013 Ta-You Wu Lecture.
This lecture was held on Tuesday, April 9, 2013 in Blau Auditorium at the Ross School of Business on the University of Michigan's Central Campus
Superposition, Entanglement, and Raising Schrödinger’s Cat
In 1935, Erwin Schrödinger, one of the inventors of quantum mechanics, illustrated his discomfort with the theory by pointing out that its extension to the macroscopic world could lead to bizarre situations such as a cat being simultaneously alive and dead, a so-called superposition state. Today, we can create similar situations on a small scale, such as putting an atom in a “bowl” and placing it on the left and right sides of the bowl simultaneously.
Superpositions are potentially useful for information processing. For example, two energy levels in an atom, labeled "0" and "1," can be used to store information like the bits in our laptops. However, as in the atom/bowl experiment, we can arrange the quantum bit to be in a superposition, thereby storing both states of the bit simultaneously. This property leads to a memory and processing capacity that increases exponentially with the number of bits. This and a related property called “entanglement” would enable a quantum computer to efficiently solve certain problems that are intractable on normal computers.
Research on precise control of quantum systems occurs in many labs throughout the world, for fundamental research, new measurement techniques, and more recently for quantum information processing. I will briefly describe experiments on quantum state manipulation and atomic clocks that employ trapped atomic ions. This talk is, in part, the “story” of my involvement in these topics that I presented at the 2012 Nobel Prize ceremonies.
Biographical Sketch of David Wineland
David Wineland was born in 1944 in Wauwatosa, Wisconsin, and was raised in Sacramento, California. He received a B.A. from University of California, Berkeley in 1965, and a Ph.D. in physics from Harvard University in 1970.
After a postdoctoral position at the University of Washington, he joined the National Bureau of Standards (now the National Institute of Standards and Technology) in Boulder, Colorado. He is a NIST Fellow and leader of an experimental group that explores the applications of laser- cooled trapped atomic ions, including the development of high-performance atomic clocks, research on quantum information processing, and tests of fundamental physical laws.