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Comment Just read the guy's home page for explanation (Score 2, Interesting) 125


follow the link to "Second Law? You must be kidding..."

"FYI -- there is some sensational press out there that makes it sound like we're planning to break/have already broken the 2nd law of thermodynamics. This is, of course, absurd -- but I think it's imperative we set the record straight before everyone starts jumping all over us.

The context.... a colleague and I received funding to study non-equilibrium switching invoking a concept called 'Brownian Ratchets' that has been well studied in nonequilibrium statistical physics over the years. The potential benefactor of this study is the chip industry, in a very broad way, as it is worried about rapidly increasing thermal budgets (chips are becoming very hot). We're simply trying to examine the physics of Brownian ratchets in a device context. A popular model for heat dissipation in binary switching (proposed by Victor Zhirnov and co-workers) looks at a two well one barrier geometry, with a gate controlling the barrier and a drain controlling the overall directionality. Each such raising and lowering of a barrier at the end dissipates energy irreversibly (during the reset step where one erases information), leading to a kTln2 dissipation per operation (kT is the thermal energy). And this analysis is usually done by assuming that you wait after you raise or lower a barrier and then let the electrons move and reach equilibrium with the surroundings. The analysis is thus based on equilibrium Boltzmann statistics -- since the electron was at equilibrium before a computation and reaches equilibrium after. What is not clear is what happens during the non-equilibrium transition phase, or if you switch before the equilibrium is reached. The aim of the study is not to attempt to deviate from cherished physical principles, but on the contrary to see what these cherished principles posit for such a situation. A ratchet is known to be able to rectify non-equilibrium noise to produce directed motion by transducing spatial asymmetries in the system (this is well recognized in nonequilibrium statistical mechanics and has been mulled over for years). The physics is well studied, but the context is perhaps new... we are interested in seeing if rectifying such non-equilibrium noise (as a ratchet does) can perhaps shave off some of the power dissipation limit associated with a drain bias in the regular example.

This is, of course, still at a toy model -- we need to worry about how to deal with compatibility of input and output, for example. Simply put, we don't know if this will bear fruit for the big picture of low-power device operation, but it's worth investigating.

That's about it... but then, cooling laptops as hot as the sun through the power of thinking or by breaking the 2nd law sounds fancier ... doesn't it? "

He's talking about studying the transient state of electrons switching in a semiconductor barrier, and how it may be useful in reduce semiconductor heating.

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