Quantum quirkiness
Your special issue on quantum weirdness (SN: 11/20/10, p. 15) was certainly
the best presentation I have ever seen.
You folks are geniuses and what you
did was little short of incredible. It
will be difficult (probably impossible)
to top it, but keep up the good work.
As an aside, could you include more
book reviews? They are my favorite
part of the issue.
Ken Lawrence, Highland, Mich.
Your articles on quantum mechanics
and entanglement were much appreciated, and I hope to see more articles on
quantum mechanics in future issues.
As Gerard ’t Hooft (who is quoted in
one article) stresses on his website,
physics amateurs such as myself cannot hope to contribute anything of
significance to quantum mechanics.
Nevertheless, we amateurs can appreciate the philosophical issues quantum
mechanics raises and engage meaningfully in the discussion, if only on the
sidelines, thanks to the ongoing discourse in nontechnical popular venues
like Science News.
It appears the field may be entering a renaissance. The evidence for
entanglement is solid, and some sort
of unseen, instantaneous, universal
connectedness has now become thinkable and even likely. Yet the underlying
mechanisms remain a total mystery.
This state of affairs would seem to
reopen the field for quantum interpretations that have been out of vogue
for decades. One hopes theoretical
physicists will take a fresh look at the
possibilities of hidden variables and
of a substantial “reality,” composed of
objects with physically real properties
not created by observation.
John Day, Santa Barbara, Calif.
Tom Siegfried’s article, “Clash of the
Quantum Titans,” is a beautifully
written piece that makes sense of an
uncommonly difficult issue: quantum
weirdness. I am convinced the central
problem with our lack of understanding quantum reality is that electrons,
protons, photons, quarks, etc., are
neither particles nor waves. The fact
that they may “act” as particles or “act”
as waves, or act both ways simultaneously, is due to the fact that humans
have constructed analogies to things
we can see, feel, know and understand.
But I suspect those tiny entities will
turn out to be — if we ever can go
beyond the “particle” or “wave” analogies — something utterly different.
When/if we ever uncover the true
nature of those tiny entities, our understanding will increase by magnitudes.
In the meantime, we’re stuck with analogies that make sense at our size scale,
analogies which simply fall short when
trying to describe things so small, even
if the analogies have been good enough
to yield mathematically and observa-tionally correct results.
Bruce Barnbaum, Granite Falls, Wash.
“Schrödinger’s cat was born 75 years
ago. Its date of death remains uncertain.” Great opening sentence! Thanks!
Patricia A. Williams, Birmingham, Ala.
The photograph of Einstein and Bohr
(SN: 11/20/10, p. 19) clearly renders a
verdict in favor of Bohr, Bell, Aspect,
et al. Though the slight blurriness of
Einstein’s shoes might be dismissed as
a lens defect, Bohr’s shoes manifestly
lack definite position and momentum.
Douglas Lackey, Wayne, N.J.
I thoroughly enjoyed the two long
articles on quantum mechanics. A comment and two questions, however. Tom
Siegfried writes, “When James Clerk
Maxwell developed the idea of electromagnetic fields....” It is worth reminding
people of the sorely underappreciated
Michael Faraday, who really developed the idea of an electromagnetic
field. Even Maxwell gave full credit to
Faraday and claimed that all he did was
mathematize Faraday’s research.
My first question is this: Siegfried’s
article says in talking about the polar-
ization of two entangled photons that
when photon A is horizontal that
photon B is horizontal also. The large
graphic in Laura Sanders’ article says
that photon B will be vertical. There’s
either a subtle distinction lost on me or
someone got it wrong.
The reader is completely correct about
Faraday; the phrasing should have said
that Maxwell “developed the mathematics” of the electromagnetic field.
Regarding entanglement, in some cases
entangled photons will show the same
polarization; in other cases, the polarizations will differ. It depends on the
details of how the experimental apparatus to entangle them is arranged. And
measurement can indeed sometimes
destroy entanglement irretrievably, but
in some cases can also restore it, depending on the nature of the experiment.
— Tom Siegfried and Laura Sanders
I was surprised to read that double-
slit interference patterns have been
observed with 70-atom fullerenes. Is
there any theoretical or experimental
maximum size for particles that show
this effect?
Dean Brown, via e-mail
In principle, quantum effects apply to
all matter of whatever size. As objects
get bigger, however, interactions among
their own internal parts or with other
particles in the environment usually
eliminate the quantum effects so rapidly
that their detection is very difficult and
at some point becomes technologically
infeasible. — Tom Siegfried
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