Communications of the ACM

In early 1935, a man named Clarence Hickman had a secret machine, about six feet tall, standing in his office. Hickman was an engineer at Bell Labs, and his invention was, at the time, a device without equal on earth, way ahead of its time.

CACM Administrator

The following letter was published in the Letters to the Editor in the July 2011 CACM (http://cacm.acm.org/magazines/2011/7/109897).
--CACM Administrator

Tim Wu's viewpoint "Bell Labs and Centralized Innovation" (May 2011) was inaccurate regarding a specific example of research at Bell Labs.

Wu wrote, "Bell's scientists did cutting-edge work in fields as diverse as quantum physics and data theory. It was a Bell Labs employee named Clinton Davisson who would win a Nobel Prize for demonstrating the wave nature of matter, an insight more typically credited to Einstein than to a telephone company employee." However, Albert Einstein actually discovered that some perplexing data regarding the photoelectric effect could be explained through a hypothesis proposing that light, previously described purely as waves, could behave as particles, now called photons. Others, in particular Louis de Broglie, proposed that matter, previously viewed as particles, could be described by waves. While the Davisson-Germer experiment confirmed de Broglie, neither Davisson nor Lester Germer at the time knew about de Broglie's research; see http://courses.science.fau.edu/voss/modphys/pdf/Ch05_2.pdf.

Germer (a casual acquaintance) told me he and Davisson did not realize the data showed the wave nature of matter initially due to the wave nature of matter being a rather esoteric idea at the time. That is, they discovered something very important but somewhat by accident. It took time before these two researchers realized what they had actually measured.

There were practical reasons (of interest to a telephone company) for Davisson's and Germer's research, including vacuum tubes, which were then used in amplifiers. Electrons arrive at a vacuum tube's anode with enough energy to cause secondary emission of electrons at the anode, in some cases degrading a vacuum tube's performance.

Understanding how electrons interact with an anode was obviously useful in any attempt to improve the anode's design.

William Zaumen
Palo Alto, CA

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AUTHOR'S RESPONSE:

Zaumen is correct. Davisson demonstrated that all particles, not light, have wave-like properties; for example, electrons, and even people, have a wave-like nature. Zaumen is also correct in saying that Einstein worked in a field that assumed light was wave-like, showing its particle-like properties.

Tim Wu
New York