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More on Spintronics
segment writes "'We have discovered the equivalent of a new 'Ohm's Law' for spintronics - the emerging science of manipulating the spin of electrons for useful purposes,' says Shoucheng Zhang, a physics professor at Stanford. 'Unlike the Ohm's Law for electronics, the new 'Ohm's Law' that we've discovered says that the spin of the electron can be transported without any loss of energy, or dissipation. Furthermore, this effect occurs at room temperature in materials already widely used in the semiconductor industry, such as gallium arsenide.'"
At subatomic levels, every process is 100% efficient. The basic principles that you learn in mechanics which warn you that there is no such thing as a perpetual motion machine, etc... are results of statistics and macroscopic effects. Microscopic is not miniaturized macroscopic.
Spintronics is promising, but I doubt that it will be the NBT. Quantum-dot Cellular Automata (QCA), which encodes binary information based on electron orientation, seems to hold more promise. It is highly scalable, small, can hybridize with CMOS, and can already be fabricated at low temperatures. With the addition of clocking regions to lower inter-dot tunneling barriers, even pseudo-pipelining is realizable. Perhaps the best thing about this is that it all cells are coplanar! I just attended a conference (IWQDQC) on Quantum Computing, and believe me, spintronics faces its share of problems.
If you read the abstract for the actual paper you'll
see that they are basically talking about a more
sophisticated version of a quantum-hall effect,
i.e. they are talking about the evolution of a
correlated state, a different one from superconducting
condensate or bose condensate but another type
of correlated state. Correlated states can result
in negligible dissipation (e.g. superconductivity
or superfluidity). They will not be immune from
thermal fluctuations esp. at room temperature nor
will they be immune from dissipation at impurities
and such. But other than that having spin supercurrent
seems quite possible.
And I am a graduate student doing physics research
in the are of high-temperature superconductivity.
Mr. Zhang is quite well known in this area since
he proposed a so called SO5 theory which aimed to
explain everything about high-Tc in one elegant
formalism (his theory is oversimplified at best).
He has worked with Bob Laughlin a lot lately (Laughlin
got a Nobel prize for his theoretical work on, you
guessed it, quantum-hall effect). So these people
are legit, they know what they are talking about
but Zhang has been known to throw wild ideas out
there (and more often than not even those have
at least a grain of truth in them).