When electronic engineers hear the term "tunneling" we may think first of the tunnel diode (also known as the Esaki diode, see here),
developed in the late 1950s and which was heralded at the time as the
next big thing in switching components. For various reasons, this
two-terminal device never really caught on, and is now used only in some
specialized microwave applications such as oscillators. The diode's
operation can be explained only using quantum theory and probabilistic
concepts, and it's a pretty strange world down there: it's a
sub-microscopic event in the truest sense of the term.
But last week
we had major news developments regarding tunneling on a macroscopic
scale. First, there was the final rescue of the Chilean miners trapped
for many weeks. Although the "human interest" aspects of the rescue
attracted the most attention, there was an amazing amount of substantive
engineering required, even to just locate them, see here; as well as contributions from instrumentation and medical/physiological experts at NASA.
The other development was the "breakthrough" (literally) in the 35.4-mile
Gotthard Base tunnel link through the Swiss Alps. There is an excellent
general news article (don't see many of those these days, do we?) with
facts, photos, and a revealing schematic, see here.
I had the privilege of being in Switzerland the day before the
breakthrough and you can't imagine what a sense of nation pride and
determination there is about things like this tunnel. The breakthrough
would be televised, of course, major government figures would be there,
and it was almost a national holiday (it got attention at least
comparable to news about Paris Hilton's latest arrest here, that's for
construction on the project started in 1995, and it has about another
seven years to completion; yet so far it is on time and on budget. The
genuine respect and admiration shown by the population for the engineers
was stunning, and very different than what we see in the US; the Swiss
follow their engineers, while our "news" is about the successes and
tribulations of those Karadashian sisters.
of your thoughts of whether this Swiss tunnel is worth the cost versus
its benefits, you have to admire the engineering expertise in planning
and execution, as well as the long-term commitment. We don’t often see
those attributes in projects these days.
we have tunneling on a scale which is very different in every
aspect--size, commitment, cost, impact, science and engineering
underpinnings--from the tunnel diode. We really need to give this other
tunneling the attention and respect it deserves, of course. The other
lesson is that a story with a high human-interest factor will get more
world-wide attention that one without, regardless of relative size
(thanks to the cultural impact of things such as Oprah and People magazine).
Even more amazing, tunnels such as the more modest (9 miles/15 km) Gotthard Rail Tunnel were completed in the 19th
century: how did they manage to align those, I wonder, in the days
before today's optical and electronic instrumentation, computers,
calculators, and other "modern" tools? It should make us both a little
humble and also proud, as we talk about the problems of our
next-generation IC issues.♦
One thing I'd
like to know more about is how they work out the drilling alignment so the two
sides meet perfectly. It's got to be as challenging as our nanometer-class IC
design and fabrications issues, despite the grossly different scale. While I
know it is easier to do this alignment now with our lasers, GPS, and other
sophisticated tools than it was years ago, there are still many first-,
second-, and third-order sources of error and needed corrections, including the
curvature of the earth over the distance, and local variations in the force of
gravity. A tiny error anywhere along the way, whether in initial position or
angular measurement, would have enormous consequences as the tunneling
continued, and could not be corrected via a software fix, that's for sure.