From: John K Clark (johnkc@well.com)
Date: Thu Apr 17 1997 - 22:28:07 MDT
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>>Me:
>>Max Planck started the entire revolution by proposing that energy is
>>NOT continuous, everything followed from there. Take a beam of light
>>for example, it has momentum nhf, h is the Planck constant, f is the
>>frequency of the light, and n is an INTEGER, the number of photons.
>>Digital.
>Dejan Vucinic <dejan@mit.edu>
>The formula is correct, but your conclusion is not. While n is an
>integer, f is not.
If some physical property comes in units, 1c, 2c, 3c, 4c, ... then that
property (in this case momentum) is digital, the constant c can be pi, e, or
any real number except zero, it does not matter. The absolute value of one
unit is not important, the point is that the difference between one unit and
the next comes in steps, integers. Digital.
>>Me:
>>If you want to find the momentum of an individual photon, hf, you
>>can find it by using the formula hN/X , h is the Planck constant
>>again, and N is the number of wave crests the photon makes over a
>>distance X. Digital.
>Dejan:
>Another wrong conclusion. One: N is not an integer. A photon that
>has one "crest" over one meter has one point three crests over one
>point three meters.
1.3 crests? Is that anything like 1.3 pregnancies? As I said, as you get to
the end of distance X there will always be uncertainty over whether something
is a crest or not, but the uncertainty can be made arbitrary small simply
by making X larger because that increases the number of crests you are
certain about and leaves the number you are uncertain of unchanged. Now you
have better knowledge about what the momentum is, but because X is now larger
you have less knowledge about where the photon is.
>Two: the number of crests depends on the frame of reference.
Everything depends of the frame of reference, except the speed of light.
All photons will be red shifted or blue shifted, the amount of the shift will
depends on how fast you're moving relative to the source, and at any instant
the shift will be a constant for all atoms of any element in the source.
>Counting crests of photons is a mental crutch.
Why? Seems like a perfectly respectable activity to me, absolutely nothing to
be ashamed of, it's entirely natural, just part of life. Physicists do it,
engineers do it, even educated technicians do it. Let's do it, let's count
wave crests.
>In reality, what you can do is measure the energy of your pet photon.
>Unfortunately, in the process you're destroying the photon itself, so
>the accuracy of your measurement is not constrained by the Heisenberg
>inequality, but rather by the construction of your apparatus.
You can measure the energy of a photon as accurately as you want but
regardless of how good your apparatus is, the more you find out about the
position of a photon, or anything else for that matter, the less will be
your knowledge of its momentum.
>And you are right in that randomness is not a continuous quantity.
>In fact, it's not a quantity at all, it's a concept people have
>trouble imagining because it's not "intuitive".
When we say we understand some physical phenomena we mean we have found the
cause, randomness by definition is a phenomenon that has no cause, so if we
don't understand it, it's only because there is nothing to understand.
>However, an incredible mountain of evidence suggests that quantum
>mechanics is how universe works
True, but it's not randomness that makes Quantum Mechanics so weird, it's
spooky action at a distance, retroactive causes, and the question of
exactly what an observer is and is not that makes it all so bazaar. The crazy
experiments that proved Bell's inequality is violated should not have turned
out the way they did, but they did.
>>Me:
>>If you want to find the energy of a photon multiply the digital
>>momentum by a constant, the speed of light.
>Dejan:
>No, it just says that our historical choice of units for "energy"
>and "momentum" was arbitrary, so we invented a "constant" to make
>it sound less embarrasing.
What on earth are you talking about? Plank's constant h comes in units
momentum times length, wavelength comes in units of length, divide the Plank
constant by wavelength and you get the momentum of the photon, it's true
here, there, and everywhere. Use the Metric system, or the English system,
or the measuring system favored by the 3 headed 5 armed 7 eyed creatures of
the Virgo cluster, it doesn't matter in the slightest, c will still come in
units of length divided by time, and if you want to find the energy of a
photon multiply the momentum by the speed of light, and the speed of light is
a constant, always, everywhere.
>in the Universe and in my current profession c == h == 1.
One what? c and h do not come in the same units, but the units are related,
sure you could change the size of the units of c and make c whatever you want,
but then h would have to be fixed.
John K Clark johnkc@well.com
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