Skip to main content Skip to navigation


Physics & Astronomy – Stephenson Lecture – Dr. David Wineland

About the event


Dr. David Wineland

Nobel Laureate, Philip H. Knight Distinguished

Research Chair and Research Professor,

University of Oregon

Informal reception in the SPARK atrium immediately following the lecture.


For many centuries, and continuing today, a primary application of accurate clocks is for precise navigation. For example, GPS enables us to determine our distance from the (known) positions of satellites by measuring the time it takes for a pulse of radiation emitted by each satellite to reach us. The more accurately we can measure this duration, the more accurately the distance is known. When performed with a network of satellites, we can find our position in 3 dimensions. Atoms absorb electromagnetic radiation at precise discrete frequencies. Knowing this, a recipe for making an atomic clock is simple to state: we first need an oscillator to produce the radiation and an apparatus that tells us when the atoms maximally absorb it. When this condition is met, we can simply count cycles of the oscillator; the duration of a certain number of cycles defines a unit of time. For example, the internationally agreed on definition of the second corresponds to 9,192,631,770 oscillations of the radiation corresponding to the cesium “hyperfine” transition. Today, the most precise clocks count cycles of radiation corresponding to optical wavelengths, or around a million billion cycles per second. To achieve high accuracy, many interesting effects, including those due to Einstein’s relativity, must be accounted for. In this talk I will focus on atomic clocks derived from optical transitions in atomic ions.

For more information, contact


Jann Dahmen-Morbeck
(509) 335-1698