[HN Gopher] Coupled Oscillators for Computing (2020)
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Coupled Oscillators for Computing (2020)
Author : nickpsecurity
Score : 39 points
Date : 2024-09-10 13:53 UTC (4 days ago)
(HTM) web link (pubs.aip.org)
(TXT) w3m dump (pubs.aip.org)
| Animats wrote:
| That's fascinating. I've fooled around with coupled oscillators,
| using 555 timers, and seen how little coupling is needed to get
| synchronization. And that you can synchronize at 2:1 or other
| ratios, although not as easily as 1:1.
|
| The new idea here is that you can have coupled oscillators
| running at very different frequencies, and only the ones that are
| close in frequency will couple. So it's sort of like frequency-
| division multiplexing, or radio. In a radio receiver, there's
| only one time-varying voltage coming in, but in that one number
| is the entire spectrum. So this offers the possibility of
| connecting some large number of elements without a large number
| of interconnects.
|
| It takes a lot of cycles to do anything with phase locked
| systems. Maybe. There are efficient modulation strategies.
|
| It's a new way to think about analog computing. Not clear if it's
| better.
|
| If biological brains were doing this, researchers should be
| seeing far more high-frequency activity than is actually
| observed. There's speculation that something in biological
| neurons ought to be going fast, because brains seem to get more
| done than ought to be possible with such slow signals. So far,
| nobody has found that. EEG measurements, even at the single
| neuron level, seem to be below 30 Hz. There was an article on HN
| a few weeks ago with speculation that something optical was going
| on. But it was just speculation.
| kragen wrote:
| yeah, if memory serves, the 2:1 coupling is how the parametron
| mentioned in the article works; given a reference frequency
| signal such as 6 gigahertz and some oscillators that can
| oscillate around 3 gigahertz, you have two possible frequency-
| locked phases that can serve as 1 and 0. one of the half-
| frequency oscillators serves as a phase reference for the 1
| level and everything else is measured relative to it
|
| hmm, now i see that the article explains this, but i guess i'll
| leave this here as a simplified summary in case that it's
| useful to somebody
| dr_dshiv wrote:
| There are a lot of high frequency electrical patterns in the
| brain. Individual neurons have a max frequency of less than
| 200hz (most less than 100hz), but volleys of neural populations
| can phase lock to much higher frequencies. The hair cells in
| the ear phase lock to sounds up to 8000hz-- this is followed by
| phase locking in the auditory nerve and further has been
| followed all the way to cortical synchronization. In humans
| only measured up to 1200hz in cortex with EEG, but this seems
| to be a measurement challenge. High frequency neuroscience has
| a big measurement challenge, actually. Very expensive.
|
| If you are interested in topics like coupled oscillators,
| synchrony and entrainment, I cowrote a paper that you may
| enjoy. We cite the OP (2020).
|
| https://www.frontiersin.org/journals/neurorobotics/articles/...
| kragen wrote:
| thank you very much for sharing this!
| kragen wrote:
| in the 01950s the parametron was one of many approaches being
| considered for computing at microwave frequencies; it's kind of
| amazing that it took until the 01980s for microwave computing to
| realize its potential, and then by way of conventional 'level-
| based' combinationial logic and flip-flops rather than through
| oscillator-based computing
| Vecr wrote:
| If we could compute faster we'd be able to do digital visible
| light interferometry, but for now we're stuck with lenses and
| mirrors bolted to heavy tables, and our telescopes have to be
| very close together.
| kragen wrote:
| well, i can see best around 540 terahertz, so i think you'd
| need digital state transition rates around a couple petahertz
| for digital visible light interferometry, about six orders of
| magnitude faster than this cellphone. that's clearly
| physically possible, but one or another technology might be
| able to compute much faster than this cellphone while topping
| out in the low terahertz
|
| such speeds would likely require that most bit operations be
| reversible to avoid vaporizing due to landauer's limit
| (perhaps coincidentally also first proposed by von neumann)
| fanf2 wrote:
| We would also need an optical atomic clock at each receiver
| in order to have enough time resolution to correlate the
| signals correctly. A few optical clocks exist but they are
| still highly experimental.
| kragen wrote:
| maybe you could just send a reference light beam between
| the receivers over an optical fiber to provide a phase
| reference?
| Vecr wrote:
| The dream would be a planet-sized optical telescope, but
| even a European country sized 'scope would have trouble
| with your idea.
| kragen wrote:
| people already send light beams over ocean-length optical
| fibers (that's how we're talking). this is achieved by
| the use of erbium-doped fiber amplifiers, which preserve
| wavelength and phase information, but even without
| amplification you can reach 500 km:
| https://phys.org/news/2023-06-scientists-km-quantum-
| key.html
|
| and of course we're only talking about these rube
| goldberg setups because we're perversely trying to build
| a telescope with a giant rock in the middle of it. if we
| build the telescope in solar orbit, we can just shine a
| light through space for the phase reference
| bob1029 wrote:
| > Spiking neural networks use oscillators for generating the
| signals but do not take advantage of the nonlinear interaction
| between oscillators, and so most of them do not belong to OBCs as
| we defined them.
|
| I don't know if I share this view. The interaction between
| oscillators in a SNN is indirect but certainly non-linear by way
| of the network elements and how they process information.
|
| I would think of STDP like a biological form of injection
| locking.
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