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Remembering Norman F. Ramsey 1915-2011

Ramsey, Klepppner and Phillips, B. Phillips, JQI

From left: Daniel Kleppner, Norman Ramsey, Bill Phillips

Image courtesy of B. Phillips, JQI

Norman F. Ramsey, a giant in the field of atomic physics, passed away at age 96 on November 4, 2011. Notably, he received the 1989 Nobel prize in physics for inventing the “method of separated oscillatory fields.”

Ramsey’s interest in science was present from early readings of quantum theory as a teenager. In his Nobel autobiography he expressed sentiments that still can be heard among budding scientists. He “did not realize that physics could be a profession,” but actually began his career during a great period of modern physics.

He received two bachelor’s degrees, one from Columbia University and one from Cambridge University, U.K. After studying at the Cavendish Laboratory with the likes of Born, Dirac, and J.J. Thomson, he returned to Columbia and began graduate work on molecular beams with I.I. Rabi. It was in this laboratory that Rabi invented the magnetic resonance method, work that earned him the 1944 Nobel Prize in physics. In Ramsey’s Nobel Prize lecture, he describes his work as an extension of Rabi’s magnetic resonance technique.

Like many of his contemporaries, Ramsey was affected by the tumultuous times of WWII and spent time working on the Manhattan Project at Los Alamos National Laboratories.

He later moved to Harvard University, where he eventually retired in 1986. While at Harvard, he set up a laboratory to continue his molecular beam research. He encountered a problem with the accuracy of magnetic resonance techniques. In his autobiography he describes the experience succinctly, but in a way that sets a tone of perseverance - “I had difficulty in obtaining magnetic fields of the required uniformity. Inspired by this failure, I invented the separated oscillatory field method which permitted us to achieve the desired accuracy with the available magnets.”

Now known as Ramsey spectroscopy, this technique is used routinely throughout atomic physics and quantum information science and has applications in atomic clocks, the time-keepers for GPS. Like many physicists, the scientific pursuit was life-long calling for Ramsey and following retirement he remained active in academia.

Ramsey mentored more than 80 graduate students, including Daniel Kleppner, a faculty member of MIT and thesis advisor of JQI scientist and Nobel Prize winner Bill Phillips.

Talking of Ramsey, Phillips says, “I considered Norman a mentor, role model, and friend. He had a profound effect not only on the intellectual development of atomic physics, and indeed physics as a whole, but also on the spirit of atomic physics. I credit Norman with putting his personal stamp of openness, collegiality, and generosity in research on the field in which we work. He is an example of how a single individual can have an impact that is both scientific and personal and that endures through the generations.”

The Joint Quantum Institute joins many in saying goodbye to Norman Ramsey. His impact on the field of atomic and quantum physics is immeasurable.