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CREOL Colloquium Series: L. J. Wang "Precision Measurement of Gravity, Time and Applications"
Friday, March 21, 2008 10:30 AM to 12:00 PM CREOL Room 102
Director, Institute of Optics, Information, and Photonics,Max-Planck Research Group and the University of Erlangen-Nuremberg, Germanylawn@ioip.mpg.de
I describe our recent results and future directions in various high-precision measurement experiments. These experiments explore the quantum limits of precision measurements.
Three sets of experiments will be discussed.
In measuring Earth’s gravity acceleration, g, we reached a 1.5x10-9 g (micro-Gal) level. In sensitive force measurement, we show the dynamic cooling of a gram-sized, macroscopic oscillator to < 300 milli-Kelvin. And using the method and device, small forces at the femto-Newton (10-15 N) level can be measured, down to thermal limit. This force is less than 1% of a single biological molecule’s force. The method may improve the precision determination of Newton’s constant – G.
In precision time measurement, we implemented an optical-frequency atomic clock, based on a single trapped ion, reaching a stability and accuracy of ~ 6x10-15, limited by the radio-frequency reference. I will discuss their applications to Satellite time keeping and GPS-like systems.
Precision measurements yield great applications in geophysics, mining/exploration, earth-crust dynamics, test of general and special relativity, the GPS system, test of fundamental physical constants variation, and future space missions.
Lijun Wang received his Ph.D. degree from the University of Rochester in 1992. He was a Research Associate at Duke University from 1992 to 1994. From 1994 to 1996, he was a Senior Scientist at the Research Institute of General Atomics Corp. From 1996 to 2004, he was a Research Scientist and subsequently a Senior Member of the Technical Staff and Department Head at the NEC Research Institute in Princeton, NJ. Dr. Wang is currently a director of the Max-Planck Research Group, Institute for Optics, Information, and Photonics, and a Chair Professor of Experimental Physics at the University of Erlangen-Nuremberg, in Erlangen, Germany. Dr. Wang is a Guest Member of the Max-Planck Society for the Advancement of Science (MPG). He was a Visiting Fellow at JILA (1997-98). He served in various editorial capacities, including serving as a Topical Editor for Optics Letters (1999-2003).
Dr. Wang is a Fellow of the Optical Society of America (OSA), and member of the American Physical Society and the American Association for the Advancement of Sciences (AAAS).
CREOL Colloquium SeriesContact: Aristide DogariuPresentation starts at 11:00 AM preceded by mingling & refreshments from 10:30.
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