breaks,
I surely hope that last statement is false.
Think of a photo detector as marbles on an egg tray. No amount of low-frequency shaking would dislodge a marble, but shake fast enough and with enough amplitude and marbles start to jump off. Each escaping marble takes with it a little energy taken from the shaking movement.
Then imagine that the only way to detect that the tray is shaking is by counting the marbles jumping off.
Jeroen Belleman
You can't test an idea without an experiment, and a formula to verify or falsify. He understood stuff that you don't; that's not his fault.
advancement.
applications
understanding.
they shy away,
spacecraft was ditched
orders
years
have gotten a Nobel piece price,
advancement.
He predicted relativity (proven), mass increase with velocity (proven), time dilation with velocity and gravitational field (proven), stimulated emission (lasers), gravitational lensing (proven), frame dragging (proven), and the fact that gravity propagates at c (proven, and makes gravity waves mandatory.) Not bad for a patent clerk.
Of course he wrote equations. But he had to envision the reality, too.
He was just a lot smarter than you or me.
Money. There's no reason to go to the moon again. Been there, done that. We have all sorts of rovers and gadgets on Mars now. It makes no sense to send people there.
The ISS makes no sense either. It's just been an expensive way to kill people.
-- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
breaks,
"Anyone who is not shocked by quantum theory has not understood it."
-- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
breaks,
But unfortunately, many of us have lost their marbles and to busy looking for them!
Jamie
voltages
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very
ely
that
tried some
dHi John, Yeah too much reverse voltage and the LED's start avalanching on their own. But if you're below that point, then light can trigger the discharge. As you get closer to the edge, you get bigger pulses and more light sensitivity...feeble as it is.
If you go over the edge, then you get current pulses that are perhaps thermally produced. There's a band where it's spiky and noisy... above that the current becomes quiet. It's a lot like a zener.
George H.
The only difference between RF quanta and light quanta and gamma ray quanta is their wavelength and energy. A transmitting antenna shoots out zillions of time-aligned RF photons, and a receiver picks them up. They are too weak to detect individually.
At 1 MHz, a photon has an energy of 6.6e-28 joules, so it takes a lot of them to make a detectable radio signal.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
Ok, I'll bite... How many?
Yes.
Because you can construct experiments where the diffraction pattern is observed even with only one photon in the apparatus at a time.
Not an explanation, but the techniques of radio astronomy have been extended now up to the visible. The only *extremely* tricky bit proved to be getting the path compensators to work in real time. COAST and Magdalena ridge observatory are now operating optical telescopes using radio interferometry techniques at optical wavelengths (actually near IR). And much earlier Hanbury-Brown & Twiss took a radio-astronomy correlation formalism to derive intensity intereferometry which provides a way to measure the diameters of the brightest stars.
It is possible to analyse these experiments using either classical electromagnetism or quantum mechanics* (although the latter treatment is more difficult algebra). See for example:
-- Regards, Martin Brown
Only in the geometrical optics approximation. In reality they behave as if they have explored every path open to them and their wavefunction at their destination determines the probability of detecting them.
And you get the same result using classical waves from electromagnetism.
Classic example where your "why you have a shadow" falls flat on its face is the case of diffraction around a circular disk. There is a bright spot dead centre on axis behind the disk. An observation that was actually made of Titan in front of a star when to everybody's surprise the signal at mid occultation was way brighter than it should have been from diffraction alone - the first hint of an atmosphere.
Only because we have a preferred length scale for thinking about things. If we could maniplate things at nuclear densities then we would be able to make them jump through the same hoops as optical photons. The latter and down to X-rays just happen to be conveniently the right size to interact nicely with ordinary matter.
To have a well defined energy an individual photon wavefunction must have a certain length as a multiple of its nominal wavelength. The additional requirement of causality puts some hard constraints on what this must look like. Coherent sources trade well determined wavelength but have large numbers of indistinguishable photons in the beam.
Radio transmitters, lasers and masers are all coherent emitters whereas thermal sources are not.
Maybe. I would still prefer that it was something special about the first supernovae in the universe that made them atypically bright. Observations will eventually determine if there really is dark energy and how much is required to match simulations to our observations.
-- Regards, Martin Brown
On a sunny day (Fri, 04 May 2012 15:38:25 -0700) it happened John Larkin wrote in :
have gotten a Nobel piece price,
advancement.
Gravity probe B, the experiment, failed, because their 'marbles' starting to move wildly. :-) After many month of tinkering with the data they could sort of make a curve fit to frame dragging.
Seems the jury is still out on that, some say that experiment only measured the speed of light.
(proven, and makes gravity waves mandatory.)
Now you contradict yourself, 'waves' and light is particles? [1]
After years of investigating new designs for mouse traps and perpetual motion machines he finally pulled his own joke on the scientific community. He also had that attitude to take other's work (Bose) for example, and hang his own name on it (Bose-Einstein condensate). Einstein was much more a political figure, that is why he was not in the WW2 nuke design group either.. If they really thought he was that good that would have been where he worked. He was much of a symbol, like that Chinese Chen nowadays, poor Chen, now to the US, just like Einstein.
He was politically shrewd?? He died, and among his last statements was that he failed.
There is now commercial interest to mine asteroids I did read this week. There is a very good reason to colonize other planets and go to other stars, not sure how much time we have here, but mosquitos seem to be able to survive in space, so maybe they will rule the galaxy, if not already...
Agreed.
An orbiting station as a step to other planets makes sense though, assembly point in space.
[1] The 'frame dragging is also predicted by gravitation shadowing theories like Le Saga, and there if simply follows from logic, a recent physics paper rejects the whole space-time coupling idea...In a Le Saga system, where gravity is caused by particles (not waves) that randomly travel in all directions, such particles, when traveling through the earth, would get a momentum in the direction of rotation (and motion) of the earth, and in turn affect anything orbiting it with a force in that direction. The faster clock at higher altitude can, in that theory, be explained by more particles intercepted close to earth, giving less object density there (less compressed [2]), and a pendulum (nucleus with orbiting stuff if you must) or say clock, will then have less mass, and move slower, than out in space far away, and I even predicted an asymmetry there (H versus V close to earth). No need for mathematical onanations at all.
[2] exactly opposite of the current idea and does away with 'singularities', as now we have a maximum when all particles are intercepted. Black hole? Did ANYBODY of those mathemsuckians ever LOOK at a picture of a galaxy? If they did they would see that the galaxy is much like a garden sprinkler, spitting out matter that forms (condenses?) into stars. Matter is NOT falling INTO the center, the center is CLEARLY very very bright. So that also explains the spiral arm speed anomaly.Really we live in flat earth times, and very little hope that the ape colonies we are will change view fast. Unless their immediate existence is endangered, perhaps too late, as then all the wrong theories will kill their fans,,,, And the ones with the right theories and understanding will win the wars. Either that or dinos ways, they could not figure out how to stay alive as a species. I do not think the few extra neurons we have over dinos are that much of a guarantee, not even counting aggressive other species in the galaxy looking for planets to mine. Chances? probabilities? Maybe mosquitos anyways?
I guess my wording was unclear: My point was that even though most light we encounter is quantized (such as in the single-photon experiment you mention), that's only to be expected because of the way we generate the photons, via (quantized) electron energy level changes.
What is not so clear is whether all EM radiation must therefore be quantized. My example (below) of synchrotron radiation would seem not to be intrinsically quantized by the usual discrete electron energy levels in atoms. The charged particles are just undergoing continuous angular acceleration. Is the resulting EM quantized? How can we tell, since all detectors (that I know of) work via electron energy level changes?
Interesting stuff! But I'm afraid it doesn't help with my original conundrum, the idea that some little Maxwell's Demon gets out his little scissors and snips neat little quanta from the EM radiation of a continuous process like oscillating or orbiting charge.
Maybe the answer is simply that the math works out properly, and that's as far as anyone can tell. If so, then we could say that EM radiation always behaves *as if it is* quantized. But since there is no way to know what is "really" happening (whatever that means), then I guess it's not a problem to say that light *is* quantized.
Best regards,
Bob Masta DAQARTA v6.02 Data AcQuisition And Real-Time Analysis
To make things easier, one could in theory, make a low (very low) constant current source to reverse bias the LED with a long enough time response for correction, to allow the detection of these little guys straddling across that bridge!
If one could measure the reverse break down current of a desirable point, you then can apply a current source that could maintain a better control point, one that has a very sharp knee to it, like the use of a Mosfet for example. Bipolar sound a little to noisy to me at those low currents.
PV effects on the diode, is in my opinion, going to effect your current source, if not properly compensated.
It's a rainy day here in CT. Maybe I'll set up a simple current source at the bench and perform some test.
Jamie
have gotten a Nobel piece price,
advancement.
move wildly. :-)
machines
He signed the letter to Roosevelt that started the Manhattan Project.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
It's easy to make a radio receiver that reliably detects a picojoule RF burst at 1 MHz, and that would be about 1.5e15 RF photons.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
If you mean "quantized" to mean "photons are only available at some list of discrete energy levels", then that's not true. Photons can exist at any energy level. By "quantized" I mean that a given photon carries a definite amount of energy, and, when it's detected, all of it disappears into some other form of energy. It's not like a wave in a pond that can be partially absorbed, or a classical wave that can be split in two parts by a partial mirror.
It might be less confusing to refer to a photon as a quanta of energy, namely an indivisible packet.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
must
would
consciously
very
weakness."
your
eyes.
where
sensitivity.
over
on a
from
if
it
why.
Exactly. But only if you want them to be waves everywhere except inside photodetectors. ;)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
It's an experimental fact. Starting with the Planck formula that solved the "Ultraviolet Catastrophe". Classical equipartition (a theorem of statistical mechanics) calls for every degree of freedom of a system in thermal equilibrium to have the same mean energy, namely kT/2.
A cubical box has an electromagnetic mode density proportional to frequency squared, so the power spectral density of cavity radiation was predicted to go as frequency squared, with no short-wavelength cutoff--hence "ultraviolet catastrophe". Planck's formula presupposes a photon packet size of h*nu, and the first estimate of Planck's constant came from curve-fitting the observed spectrum.
Shot noise is another excellent confirmation.
But a photon is merely an elementary excitation of a normal mode, not a thing like a brick or an electron. Willis Lamb's article "Anti-photon", and a supplementary issue of Optics & Photonics News in 2003 was dedicated to a discussion of what a photon was. There were half a dozen or so articles by the most respected names in the field. All of them had very definite opinions as to what a photon was, and no two of them agreed.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
Thanks.
-- Reply in group, but if emailing add one more zero, and remove the last word.
On a sunny day (Sat, 05 May 2012 07:14:55 -0700) it happened John Larkin wrote in :
machines
That is just a political act, nothing to do with science.
On a sunny day (Sat, 05 May 2012 07:14:55 -0700) it happened John Larkin wrote in :
machines
That is just a political act, nothing to do with science.
PS John. I was thinking if you reason your way, then even Ohms come as particle: resistors come in Ohms, quantisied, but resistors can take any value... R = U/I,
;-)
I want my Nobel now!
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