Hi Hal, About Moore's law -- to appreciate how far this Time & Frequency field has come, the very first paper in the NIST archive, from 1949, describes the 23.87 GHz ammonia molecule clock, which was accurate to 1e-7 (yes, less than laboratory quartz or precision pendulum):
"An Atomic Standard of Frequency and Time" http://tf.boulder.nist.gov/general/pdf/1.pdf For those computer history nuts among us, don't miss the preceding article in the PDF which mentions NBS/NIST's first computer (2.75 kbyte memory, 864 microsecond addition time). Comparing the ammonia clock with the Yb clock, that's 11 decades of atomic clock improvement over a span of 60 years. Meanwhile my laptop has 6 or 7 decades more memory and cpu speed than the NBS computer from 60 years ago. You see who's winning the Moore's law race... /tvb ----- Original Message ----- From: "Hal Murray" <[email protected]> To: "Discussion of precise time and frequency measurement" <[email protected]> Sent: Friday, August 23, 2013 10:39 AM Subject: Re: [time-nuts] Yb clock - NPR Story on Atomic Clocks > >> Optical clocks keep getting a little bit better each time they try this or >> that. They still have a way to go before you will have one running 24/7/365 >> without it costing more than even NIST can afford to spend. > > From Daniel Kleppner's Time Too Good to Be True > Physics Today, March 2006 > http://scitation.aip.org/journals/doc/PHTOAD-ft/vol_59/iss_3/10_1.shtml > > The accuracy of these clocks has improved by roughly a factor of 10 every > decade since they were introduced in the mid-1950s and in the next few years > the accuracy is expected to reach 1 part in 10E16. > > Exponential, just like Moore's law. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
