Improving the Tick-Tock of the Atomic Clock
Telling Time to an Accuracy of One Second in the Lifetime of the Universe
Modern atomic clocks allow us to measure time more precisely than any other physical quantity. This remarkable timekeeping capability lies at the heart of many important everyday technologies, such as the communications networks that support the internet, and the global positioning and navigation systems we fondly refer to as GPS. Time measurements with current state-of-the-art precision and accuracy levels can be leveraged as sensitive probes into the fundamental laws of science. They can be used to test Einsteinís theory of relativity, to search for variations in the fundamental constants of nature, and to search for dark matter.
Next-generation timekeepers hold promise for new measurement capabilities and applications, such as gravity sensing for geodetic applications. The most advanced atomic clocks being developed today are known as optical clocks. One type of optical clock, the optical lattice clock, has been rapidly improved since its first inception one decade ago and is the focus of intense research and development worldwide. These clocks will allow us to measure time with an accuracy of one part in 1018, equivalent to about one second in roughly 14 billion years, the age of the universe. These clocks will be broadly discussed, together with recent efforts at NIST towards operating such a clock at the quantum-mechanical limit, and a brief survey of advanced international timekeeping networks and their scientific impact.
Andrew Ludlow is a physicist and project leader in the Time and Frequency Division of the National Institute of Standards and Technology (NIST) in Boulder, Colorado. His main research activities include the development of optical atomic clocks, cold atom systems and quantum metrology, and ultrastable optical sources and laser interferometry. He currently leads research and development of the ytterbium optical lattice clock at NIST.
He has been an author on more than fifty scientific journal articles in the field of atomic clocks. He serves on a variety of technical, scientific, and editorial committees. Among other awards, he received the DAMOP Thesis Prize of the Atomic, Molecular, and Optical Physics Division of the American Physical Society for his doctoral work, Department of Commerce Gold Medal Award, the Young Scientist Award of the European Frequency and Time Forum, and the Rocky Mountain Eagle Award for Scientific Achievement.
Andrew earned a BS in Physics from Brigham Young University and a PhD n Physics from the University of Colorado, working at JILA Institute of Physical Sciences run jointly by CU and NIST. After completing his doctoral work at CU he was a National Research Council Postdoctoral Fellow at NIST, where he has since become a research physicist and project leader.