FWIW I am also a physicist and the interconnect energy discussion also seemed wrong to me, but I hadn’t bothered to look into it enough to comment.
I attended a small conference on energy-efficient electronics a decade ago. My memory is a bit hazy, but I believe Eli Yablonovitch (who I tend to trust on these kinds of questions) kicked off with an overview of interconnect losses (and paths forward), and for normal metal wire losses he wrote down the 12CV2 formula derived from charging and discharging the (unintentional / stray) capacitors between the wires and other bits of metal in their vicinity. Then he talked about various solutions like various kinds of low-V switches (negative-capacitance voltage-amplifying transistors, NEMS mechanical switches, quantum tunneling transistors, etc.), and LED+waveguide optical interconnects (e.g. this paper).
It seems from the replies to the parent comment that the 12CV2 formula is close to the OP formula. Score one for dimensional analysis, I guess, or else the OP formula has a justification that I’m not following.
I’m fairly confident now the Landuaer Tile model is correct (based in part on how closely it predicts the spherical capacitance based wire energy in this comment).
It is fundamental because every time the carrier particles transmit information to the next wire segment, they also inadvertently and unavoidably exchange some information with the outside environment, thus leaking some energy (waste heat) and or introducing some noise. The easiest way to avoid this is to increase the distance carrier particles transmit a bit before interactions—as in optical communication with photons that can travel fairly large distances before interacting with anything (in free space that distance can be almost arbitrarily large, whereas in a fiber optic cable it is only a number of OOM larger than the electron wavelength). But that is basically impossible for dense on-chip interconnect. So the only other option there is fully reversible circuits+interconnects.
So I predict none of those solutions you mention will escape the Landauer bound for dense on-chip interconnect, unless they somehow involve reversible circuits. Low voltage doesn’t change anything (the brain uses near minimal voltages close to the Landauer limit but still is bound by the Landauer wire energy), NEMS mechanical switches can’t possibly escape the bound, and optical communication has a more generous bound but is too large as mentioned.
FWIW I am also a physicist and the interconnect energy discussion also seemed wrong to me, but I hadn’t bothered to look into it enough to comment.
I attended a small conference on energy-efficient electronics a decade ago. My memory is a bit hazy, but I believe Eli Yablonovitch (who I tend to trust on these kinds of questions) kicked off with an overview of interconnect losses (and paths forward), and for normal metal wire losses he wrote down the 12CV2 formula derived from charging and discharging the (unintentional / stray) capacitors between the wires and other bits of metal in their vicinity. Then he talked about various solutions like various kinds of low-V switches (negative-capacitance voltage-amplifying transistors, NEMS mechanical switches, quantum tunneling transistors, etc.), and LED+waveguide optical interconnects (e.g. this paper).
It seems from the replies to the parent comment that the 12CV2 formula is close to the OP formula. Score one for dimensional analysis, I guess, or else the OP formula has a justification that I’m not following.
I’m fairly confident now the Landuaer Tile model is correct (based in part on how closely it predicts the spherical capacitance based wire energy in this comment).
It is fundamental because every time the carrier particles transmit information to the next wire segment, they also inadvertently and unavoidably exchange some information with the outside environment, thus leaking some energy (waste heat) and or introducing some noise. The easiest way to avoid this is to increase the distance carrier particles transmit a bit before interactions—as in optical communication with photons that can travel fairly large distances before interacting with anything (in free space that distance can be almost arbitrarily large, whereas in a fiber optic cable it is only a number of OOM larger than the electron wavelength). But that is basically impossible for dense on-chip interconnect. So the only other option there is fully reversible circuits+interconnects.
So I predict none of those solutions you mention will escape the Landauer bound for dense on-chip interconnect, unless they somehow involve reversible circuits. Low voltage doesn’t change anything (the brain uses near minimal voltages close to the Landauer limit but still is bound by the Landauer wire energy), NEMS mechanical switches can’t possibly escape the bound, and optical communication has a more generous bound but is too large as mentioned.