A mechanism for what? I'm mostly of the 'shut up and calculate' school of QM. Time evolution is described by the wave function.
There are pilot wave theories of QM, I don't mind those, but AFAICT they make no different predictions. Many worlds seems crazy.
George H.
George Herold wrote
Yea, in my MNSH opinion you can do 'maaz all ye want', without a mechanism it is of little value.. As a kid, few years old, I got a book about radio (Van Aisberg 'Zo werkt de radio' (translated 'That is how radio works') and it started by describing how electrons moved, not much math in there (I was very young, had had no math anyways) but it was clear as glass to me how radios worked after reading that, he wrote the same book about TV, and then again one about transistors. It did set, in a way, my future, went straight into film, TV studio.. That is, in fact a very large complicated nano nano-second business. I build radios and transmitters without ever doing math, and discovered many things and it all worked. Electrons.
If you start with math, you have nothing, string theory is a perfect example of that, in Dutch it is called 'in de ruimte lullen', Then what do you have? Nothing but repeating some formulas. I was just doing some calculations for some project today, impossible to do if you do not know WHAT IS HAPPENING.
I know about De Broglie, and have pointed to his work (he actually got a Nobel) in sci.physics many times. When the Copenhagen conference happened, and they chose the dead cat (or was it really dead) over his theory, maybe that was a very black day. Black cat?
Oh it is worth reading that link!
Yes, many worlds is an other math dream.
wrote in news:plmo8n$j7k$ snipped-for-privacy@gioia.aioe.org:
quantum processor
slow light
And it helpfully describes the very strange behaviour of small particles in the real world. What's the largest thing that has been diffracted through Young's slits so far? I know they have done silver ions and Buckeyballs but the wave-particle duality record is now held by a 430 atom monstrosity constructed for the purpose and weighing in a 5310amu.
If you want to do everything in wave form you can but for some problems it is much easier to treat objects as particles and for others as waves. What we normally think of as particles can still be diffracted in the Young's slit experiment - it isn't just electromagnetic radiation.
It looks like it is only a practical limitation on the mass of objects that can be diffracted based on the momentum/wavelength relation.
So did Hanbury-Brown and Twiss in a controversial but ultimately successful intensity interferometer initially built in the 1950's at Jodrell Bank out of old search lights and photomultipliers and later done on a larger scale in Africa. It is interesting to note how few of their contemporaries thought there was any merit in the proposal.
It worked and they were able to measure stellar diameters for the first time since Michelson & Pease had done it with a jerry rig on the 100".
It is quite a rare book and commands a high price so look for a copy in a library! The original papers should be on ADS abstracts.
It is also dependent on the surface of the metal electrode.
Why? IOP and RSC make money from publishing research work and put it back into promoting the hard sciences in schools and elsewhere. Publishing text books gives them some income.
You can always go and read a copy for free in any copyright library and most university libraries. If you talk nicely to the librarian they will almost certainly let you in if you say what you wish to study. Some UK university libraries will let anyone in without question.
The number of people on the planet who fully understand string theory and how to apply it can be counted on the fingers of one hand.
If they ever got one to work it would churn out US junk food.
-- Regards, Martin Brown
If you google this you'll find it posted on our optics expert's (PH) web site. I downloaded a copy years ago.
(Or maybe I got it from somewhere else?)
George H.
A great book by one of my technical heroes. I have a scanned copy on my website, nicely reformatted with the help of some SED denizens.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
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Hi Phil, I'm looking for a decent reference.. book/article (whatever) to help me understand the difference between laser (coherent) light and thermal light. Any suggestions?
Trying to get my head around the graph here,
Lasers are less noisy than light bulbs?
George H.
Best one I know about is Goodman's Statistical Optics book, which I think you have.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
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Nope, but searching I found it online. muchas gracias, George H.
In some ways, they are.
A laser beam has a nearly constant envelope, so that if you plot a 2-D histogram of E_x and E_y envelope values (i.e. with the exp(i omega t) taken out) you get a noisy-looking circle. Thermal light doesn't have this property, so the 2-D histogram has a maximum at the origin.
Another way in which laser light is a lot quieter than thermal light is the photon number density vs. wavelength. You can make an interferometer pretty easily with a laser, but it's heartbreakingly difficult with thermal light except in the special case of zero path difference (white light fringes).
A few years ago, some colleagues and I did a laser + thermal light interferometer. It used a tunable diode laser interfering with an unresolved image of the Sun to detect absorption due to HF plumes from clandestine nuclear enrichment.
It worked very well, but the SNR was probably 100 dB worse than if it had been two lasers. The occupation number of photon states is a lot higher in a laser!
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
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Hmm OK. I guess I want to measure the statistics in some HB&T type of way. (Of thermal light, to distinguish it from laser light.) And that's really hard. Better is to take the Fourier transform in an interferometer. Which is simple in comparison. Re White light interferometer: We stick a 10 nm interference filter on a thermal source to make it easier to find the fringes. Say, if I took my Rubidium lamp, and filtered out one of the D lines, I'd then have a thermal source with ~ 1GHz of line width, and white light interference should be a snap...coherence length greater than 1 cm... (If I'm doing the numbers right. ~10GHz out of ~3E14 Hz, 10^4 wavelengths. ) Hmm with a pure isotopic lamp and hyper-fine vapor filter* I could do even better.
George H.
*hyper-fine vapor filter is a name I just made up... it's what they use in Rb atomic clocks to get just one of the spectral lines.ps bogged down in chapter 2 of Goodman, I'm pretty weak at statistics. GH
Yup, if you have enough aperture to get the required resolution. The HBT scheme only needs light buckets, which is really its only advantage apart from extreme coolness.
OTOH lab-scale HBT ought to be a lot easier to do nowadays, since long wavelength photodiodes are available inexpensively. That means that with a bright, high-temperature thermal source such as a short arc lamp or laser-produced plasma you can work well down the long-wavelength side of the Planck curve, where the classical correlations are comparatively much stronger. The Narrabri observatory used bialkali PMTs, which peak around 400 nm and tank by about 600. Even with blue stars the classical correlations were only at the 1% level.
Yup. That way the envelope is a few dozen fringes wide, which helps a lot.
It has to be spatially unresolved though, or else the fringes wash out. That costs a lot of light if the source isn't bright to start with.
Almost 20 years ago now, I was trying to gin up interest in an IR telescope with hemispherical coverage and no optical system to speak of. It was going to use a large array of antenna-coupled tunnel junction detectors and an IR laser supplying a reference beam. ACTJs are so wideband that I expected the fourth-order correlations to be quite reasonably sized (picture a HBT scope with 100 THz RF bandwidth rather than 30 MHz), and changing the relative time delay across the aperture (as in a phased-array radar) would allow steering.
That would measure the autocorrelation of the scene brightness, so to get the scene itself would need phase retrieval. I expected to need a few real interferometers to guide the phase retrieval algorithm, but these would also be small.
There was a fair bit of interest in this idea (at least locally), but I never got the yield of the ACTJ fabrication process anywhere close to the required level.
I took the class from Joe Goodman himself, which helped a lot, but am no statistician either. I once spent most of a vacation going through Papoulis's Statistical Signal Processing book and doing a lot of the problems. I understood it at the time but it didn't really stick--I'm obviously missing that lobe of the brain.
Joe G. is really a good guy.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
What does that mean? I can't put a lens between my bulb and interferometer?
The lamp is kinda bright (I think) 1-2 uA of photo current onto a
40 mm^2 PD at 15 cm distance. (no lens)Anyway I'll have to try next time I have it set up. The only bad part is the lamp is in the NIR so you can't see anything.
It would be a spatial auto-correlation? (I have a hard time picturing what that would look like.)
Tunnel junctions and liquid helium? I can imagine a few different ways for that to go wrong. We made Clark slug (and other types) of TJ in advanced lab... I think with about a 1-2% success rate... I do recall rewiring the low temp probe so I could test a whole bunch at once.
Yup it's fine though, I needed something meaty to read at night.
George H.
It doesn't look like anything, which is sort of the problem. ;) HBT concentrated on stars, which (being spherical) have simple autocorrelations. They did do stuff with identifying limb darkening and close binary systems as well, iirc.
No, this was all Ni-NiO-Ni with noble metal antennas, working at room temperature. I worked on the waveguide-coupled thing partly to try to improve the TJ yield, but it never got above about 40%. That was fine for a POC of the waveguide-coupled detector gizmo, but nowhere near good enough for the array.
If the project had really grown legs, we could have done a ROIC for the array, but that would have needed DARPA money. (Which, given the DoD utility of such a gizmo, would very likely have materialized.)
But as Pe'pe' le Pew said, "I can dream, can't I?" ;)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
That only works if you don't understand science. The only way an experiment can 'fail' is if it is not completed. Experiments test or measure, and while an hypothesis can fail a test, the experiment cannot be called a 'failure' because of that.
It's unlikely that a scientist would utter the 'experiment failed' phrase, or that a nonscientist would be truly aware of Bell's theorem. So, the joke is kinda funny, even before the punchline.
Sure, dreams are good... maybe someday they come true, but if not, hey they were only dreams. I've got a few dream designs, they accumulate with age. :^)
And it's fun to let them cook in the back of your brain. Bring 'em out and look at 'em once in a while.
Maybe something has changed.
George H.
Many very scientific (for that time) experiments trying to fly failed in spectacular ways.
Nope, they test for results. Measurements test for measure.
Many experiments to test for gravitational waves before LIGO failed [to show any], look it up.
And word fights is exactly why nothing gets done in for example CERN an other failed experiment. They were put to work (brainwashed by Einstein photons school bench leavers) after WW2 to
1) make a better weapon 2) make a cleaner energy source1 -> failed
2 -> failed There presence now reduced to - and justified as job creation.An experiment that worked was the invention of the steam engine. That man was a real scientist! Not to be confused with mama-tisisians who look for the God particle, multiverses and renormalization... That will never happen to them either :-)
The wheel came first, PI came later. The true scientist was the one who came up with the wheel, the babble about PI was just an attempt by the less gifted to get even and claim that invention for themselves :-)
etc etc
hehe HAHAHA
I want my replicator.
That is not failure of the experiment - it is a negative result, which is often just as useful and important as a positive result.
If an experiment tries to find gravitational waves and sees none, then that is not a failure - it shows that there were no gravitational waves that could be detected by the experiment. That might mean there are no gravitation waves at all, or they have different effects than the ones hypothesised, or perhaps different energies or wavelengths, or simply that they are very rare. All of that is useful information - it is a successful experiment.
The way an experiment can fail is if it claimed to detect waves when there weren't any (with appropriate characteristics), or failed to detect them when they were there. False positives, and false negatives, are failures. True negatives are as successful as true positives.
Of course, even a failed experiment can help teach us how to get it right the next time. It's rare that an experiment is a total failure.
CERN has been remarkably successful.
It's neatly rounded out the Standard Model of physic by finding the Higgs b oson, and a few less exciting particles. It was hoped the it might provide some leads to super-symmtrical particles but nothing has shown up - which i s a useful negative result, rather than any kind of failure.
rs) after WW2 to
CERN didn't have anything to do with either of these programs
The hydrogen bomb may have been a better weapon than the atomic bomb, but i t didn't take particle physicists to get to it.
Nuclear fusion - if it ever gets commercialised - may be a better energy so urce, but particle physicists in general and CERN in poarticular aren't par t of that program. JET and ITER are.
One has to wonder why Jan thinks that.
Which one?
They were all real engineers. Scientists publish their results. Engineers m ake stuff that works.
Those are theoretical physcists, who do have a useful function, saving the community from spending money on expensive experiments which won't work.
As if Jan had a clue ...
You don't have to know the circumference of wheel in order to build one.
Jan confusing engineers and scientists again. The wheel only had to work. T he people who calculated pi had to explain why their calculations made sens e in a way that other people could understand (not that the ancient Greek e quivalents of Jan Panteljte could have cared less about the exact value of pi).
We'd all like that and certain other products of fantasy physics, but we pr obably aren't going to get them, and we certainly won't get them soon.
-- Bill Sloman, Sydney
snipped-for-privacy@ieee.org wrote :
Nope, nothing
Any idiot can write a piece of paper with the solution to everything give or take some unresolved issues such as matter -anti-matter ratio and no useful products.
CERN is largely based on photo-multipliers and photon counting. As it seems they have no clue what is is they are doing using those to measure things, are drifted out into phantasy land with statistics, their model is not worth the paper written on.
The science is easy:
but its experiment failed:
Hopefully this is understandable for you.
mm I give those guys an A++.
ze nova bumb iz zimple toe
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