4 ms·
Communication by means of modulated Johnson noise
- pockybum522 14d agoMagic, got it. (I am floored that this works. This is amazing.)
- chicken-stew 14d agoI’m away from computer so only skimmed the article until I noticed they use the ADG90x RF switch family. IIRC that family has a single positive supply rail, and they make a nagative rail internally. The advantage is easy of implementation but you also inject some noise depending on switch position. Is this dealt with in the pub?
- oijkuij 14d agoThey do conduct an experiment to control for both switching noise, or other feed-through transmissions. They put two 50 ohm terminators on as the load, and find the receiver gets nothing. They also try cooling down one of the loads in liquid hydrogen, and the transmission resumes.
- frumiousirc 14d ago> the maximum achievable throughput is 26 bps at 1.5 m and goes down to 22 bps at 4.5 m. And when there are more than one transmitters in real world conditions instead of anechoic chamber? It's cool and all and if this work is for it's own sake, for the sake of research, no issues. But otherwise, I struggle to think of practical use cases. I grant that my imagination may be deficient.
- dist-epoch 14d ago> I struggle to think of practical use cases. I guess your not on Twitter. It's not a coincidence this research paper from 2022 got posted today.
- badatnames 14d agoWhat happened today ?
- Avicebron 14d agoI think someone from OpenAI said something like "air gapping AI can't (hypothetically) work because it will figure out a way to basically morse code across the airgap". (I think this was in response to people calling them out for not airgapping)
- TeMPOraL 14d ago> "air gapping AI can't (hypothetically) work because it will figure out a way to basically morse code across the airgap" All things well-known for good two decades and written about by x-risk/LessWrong crowd, but to date continued to be dismissed as lunacy. On one hand it's great to see it demonstrated in practice in concrete terms, on the other hand it's sad we have to basically make the mistakes ourselves, with live and close-to-dangerous systems, because we can't believe the obvious warnings.
- Avicebron 14d agoYou're likely not familiar with TEMPEST/EMSEC but this stuff was known about and discussed when designing air gaps going back to the 60s.. https://www.nsa.gov/portals/75/documents/news-features/declassified-documents/cryptologic-spectrum/tempest.pdf https://www.nsa.gov/portals/75/documents/news-features/decla... the x-risk/LessWrong crowd aren't adding anything to the conversation that seriously people haven't already considered.
- TeMPOraL 14d agoI didn't mean they first invented or described the methods, but that they've been consistently presenting a solid argument that these and other methods make airgapping and sandboxing AGI a dangerously flawed idea from the start. They are the serious people who considered this, and to date nobody listens.
- amelius 14d agoMaybe it's more of theoretical interest, e.g. the interplay between thermodynamics and information theory, etc.
- nyankosensei 14d agoFigure 9C in the paper shows testing in a wooded area. Figure 9F shows transmitted data collected in a residential building, so not a test chamber.
- mitxela 14d agoThis is extremely strange. Shouldn't this be impossible by the second law of thermodynamics? Receiving more energy when a resistor in thermal equilibrium is connected to an antenna seemingly implies that energy gets transferred from an antenna with a resistor to a an antenna without a resistor, even at thermal equilibrium. Maybe we'll later find it's an experimental subtlety, like the faster than light neutrinos.
- dist-epoch 14d agoAI will explain it, but it's against HN rules for me to post the explanation. Basically they are misleading when they say "thermal equilibrium", same physical temperature does not imply thermal equilibrium.
- daveguy 14d ago[flagged]
- TeMPOraL 14d agoFWIW, the "Significance" blurb at the very top says as much: > An interesting feature of the system is that all components of the system are at the same physical temperature, but it functions because they have different noise temperatures. (I assume it's not AI-generated.)
- mitxela 14d agoBut it should. If you can get energy to flow one way between things at the same physical temperature that seems to violate thermodynamics and allow for perpetual motion.
- sametemptjjr 14d agoonly for passive systems. what's described in this paper is not passive, it has a powered amplifier in there which lowers the "noise temperature" same way a heat pump can move heat between things at the same temperature - inside and outside of house when you start it
- sweetlimetea 14d ago[dead]
- analog8374 14d agoA cacophony of meaty slaps in morse-code.
- sellmesoap 14d agoYeah are we gonna sit here and not have a chuckle about Johnson noise article hosted by pnas.org!?!
- 1attice 14d agoI tip my hat to you sir, I had missed that
- analog8374 14d agooh well caught!
- moezd 14d ago26 bps at 1.5 m: And what exactly do we expect to carry with this communication channel? If you add horned antennas it becomes a ridiculous design just to gain a few more bytes. If you add antenna arrays then it's no longer cheap. Your transmitter's output power is basically hard limited by Boltzmann constant, so just increasing range means you will have a bad time decoding it. Digital tricks, cryogenics... maybe a few more bytes, but is it enough? I'm really struggling to see if this can be useful for anything. Dicke radiometer reference is cool, though.