[FRIAM] A wireless heat engine

[Roger Critchlow]

This turned up on TheConversation.com which I recently added to my
occasionally scanned sources.

https://theconversation.com/device-transmits-radio-waves-with-almost-no-power-without-violating-the-laws-of-physics-196271

This sort of invalidates most of my expectations about what communication
channels look like.  In this case, the physical transmitter is a tuned
antenna connected through a matched resistor to ground with a switch.  By
toggling the switch on and off it's possible to send 36 bits/second over
7.3 meters.  The receiver is essentially hearing the modulation as changes
in the noise temperature on the antenna frequency.  The PNAS article --
still paywalled -- apparently goes into details of how the receiver works
as an electron refrigerator in order to obey the second law, because the
reviewers needed to be reassured about that.

https://www.pnas.org/doi/10.1073/pnas.2201337119

-- rec --
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