[sitkack]

There were Japanese computers from the 50s that used phase between waveforms for computation, can't find an immediate reference.

Found it. http://en.wikipedia.org/wiki/Parametron

This also might be of interest http://spectrum.ieee.org/computing/hardware/dudley-bucks-for... http://en.wikipedia.org/wiki/Cryotron

For completeness there was a great talk the UW EE department a couple days ago, https://www.youtube.com/watch?v=cwl6fORHNqs on using electron spin to store information.

https://www.ee.washington.edu/cgi-bin/research/colloquium/di...