| Author |
Topic: Guitar Amps and Particle Physics |
b0b
From:
Cloverdale, CA, USA
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Posted 28 Dec 2008 10:55 pm |
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From www.noiseaddicts.com:
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When fed with a sine wave, the speaker coils cycle nicely between a positive and negative magnetic field. At the end of each cycle, the positive and negative currents in the coil cancel each other out to produce a neutral magnetic field.
When the power is cut from the amplifier at the precise moment of the end of a cycle, then the atom is held completely still. |
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-𝕓𝕆𝕓- (admin) - Robert P. Lee - Recordings - Breathe - D6th - Video |
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Dave Mudgett
From:
Central Pennsylvania and Gallatin, Tennessee
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Posted 29 Dec 2008 9:29 am
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| A small victory for "small $ science" in a world of "big $ science". |
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Stuart Legg
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Posted 29 Dec 2008 8:39 pm
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| b0b, would the same thing happen if I was traveling along at the speed of light and I turned off my lights? |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 2 Jan 2009 6:24 pm
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This has to be a joke.  When the power is cut off on any amp, it continues to work in a rapidly diminishing capacity. In other words, cutting the power off will never stop it from working "immediately", it takes time (albeit a little).
If he'd said "unhooking the speaker" instead, I might have believed him.  |
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T. C. Furlong
From:
Lake County, Illinois, USA
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Posted 2 Jan 2009 6:35 pm
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Held completely still?... except for the energy stored in the compliance and spider. Duh?
TC |
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Steve Morley
From:
Connecticut, USA
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Posted 2 Jan 2009 6:46 pm
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Well, that gong you hear is the death knell for Heisenberg's Uncertainty Principle. Thanks, b0b, it was a nuisance anyway!
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Dave Mudgett
From:
Central Pennsylvania and Gallatin, Tennessee
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Posted 2 Jan 2009 7:43 pm
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I don't think this is a joke. Murray is Professor of Atomic Physics at University of Manchester in England. The point is to hold atoms, under the influence of the speaker's magnetic alternating magnetic field, still by switching off an alternating magnetic field (it says the period is five milliseconds, or 200 Hz) very close to a zero crossing. The point is that if you shoot something at the atom and measure how it scatters, the measurements and interpretation are easier and better if the target atom is not moving.
http://www.staffnet.manchester.ac.uk/news/unilife/december2008issue/research/
http://www.manchester.ac.uk/research/Andrew.murray/publications
I interpret this
| Quote: |
| When the power is cut from the amplifier at the precise moment of the end of a cycle, then the atom is held completely still. |
to mean that the power is cut from the amplifier - i.e., between the output of the amp and the speaker - which is what Donny suggests. I agree that the transient from cutting the power to the amp would be quite long. |
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Tony Prior
From:
Charlotte NC
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Posted 3 Jan 2009 1:52 am
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| This wouldn't happen to Chuck Norris. He decides when the power goes off and the sound stops. |
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Ned McIntosh
From:
New South Wales, Australia
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Posted 3 Jan 2009 5:26 am
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Trying to precisely measure the position or velocity of atoms and other such very small objects runs into complications due to the "Heisenberg Uncertainty Principle", because the very act of measuring causes the atom or particle to be influenced by the measuring process in such a way as to adversely affect the precision of the measurement.
AFAIK, Planck's Constant is also involved in this phenmomenon, but I can't recall the exact relationship, although a vague memory suggests that the error in the measurement can be calculated using Planck's Constant as one of the functions in the equation.
I'm also thinking that holding an atom completely stationary, even in a very strong magnetic field, would also imply cryogenic conditions, to preclude any thermal energy displacing the atom?
_________________
The steel guitar is a hard mistress. She will obsess you, bemuse and bewitch you. She will dash your hopes on what seems to be whim, only to tease you into renewing the relationship once more so she can do it to you all over again...and yet, if you somehow manage to touch her in that certain magic way, she will yield up a sound which has so much soul, raw emotion and heartfelt depth to it that she will pierce you to the very core of your being. |
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Steve Morley
From:
Connecticut, USA
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Posted 3 Jan 2009 9:06 am
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It's a fascinating idea, Dave. I admit I was making a joke, alluding to the particle theory behind electrical transmission, via ions and electrons, which (so far) is linked to wave theory/quantum mechanics by Heisenburg, and to magnetic propagation by Faraday's laws. I'm probably not expressing this well, but it is as I remembered my EE education from 35+ years ago! I've tried to keep up with such things as Unification theory (off topic), but, sadly, all I can muster the energy for lately is reading a little Stephen Hawking.
Almost anytime you abruptly stop or start electrical power flow, either from or to a "port", you will get transients, whether they're controlled by damping (filtering), or not; mathematics and practical experience support this. However, I'll defer to anyone else on the subject of magnetic transients (if these are pertinent), as this is making my brain hurt, and I admit to only superficial knowledge.
Controlling the flow of electrons/ions to "stasis" is what we see in push/pull output stages of power amps, and biasing correctly insures that the "zero-crossing" point won't induce transients (distortion), which may or may not be heard in the speaker, but will be seen in the output transformer, if there is one. One desirability quality of that output transformer is it's inability to store residual energy in its magnetic field, which may exhibit as hysteresis.
Alright, back to Professor Murray: His idea is beautiful, but having read the PR blurb and the synopsis of his paper (2nd link), in Phys. Rev. Lett. 99, 133202 (2007) [4 pages]
"Superelastic Electron Scattering within a Magnetic Angle Changer: Determination of the Angular Momentum Transferred during Electron Excitation over All Scattering Angles", it seems that he's holding the calcium atom "still" magnetically, to see the relative effect of various scattering angles as the electrons hit it, that is, the angular momentum imparted by the electron at different angles. If anyone is interested enough to purchase the article (US$25), I'll chip in!
So, the question begs: What could the research reveal? I need to think about that, and hope to hear what you folks think.
BTW, I appreciate b0b picking up on the basis for the research: PA systems as physics tools!
Steve
| Dave Mudgett wrote: |
I don't think this is a joke. Murray is Professor of Atomic Physics at University of Manchester in England. The point is to hold atoms, under the influence of the speaker's magnetic alternating magnetic field, still by switching off an alternating magnetic field (it says the period is five milliseconds, or 200 Hz) very close to a zero crossing. The point is that if you shoot something at the atom and measure how it scatters, the measurements and interpretation are easier and better if the target atom is not moving.
http://www.staffnet.manchester.ac.uk/news/unilife/december2008issue/research/
http://www.manchester.ac.uk/research/Andrew.murray/publications
I interpret this
| Quote: |
| When the power is cut from the amplifier at the precise moment of the end of a cycle, then the atom is held completely still. |
to mean that the power is cut from the amplifier - i.e., between the output of the amp and the speaker - which is what Donny suggests. I agree that the transient from cutting the power to the amp would be quite long. |
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Dave Mudgett
From:
Central Pennsylvania and Gallatin, Tennessee
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Posted 3 Jan 2009 11:40 am
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| Almost anytime you abruptly stop or start electrical power flow, either from or to a "port", you will get transients, whether they're controlled by damping (filtering), or not; mathematics and practical experience support this. However, I'll defer to anyone else on the subject of magnetic transients (if these are pertinent) |
Of course there are transients - even electromagnetic waves in a vacuum have an upper speed limit. The point is that he found a simple way to significantly improve the settling time of that transient:
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| “The alternating [magnetic] field can be used to trap atoms as long as we ensure that the laser beams change polarisation along with it,” says Andrew. “We can switch the fields off about 300 to 500 times faster [than before].” That’s fast enough to ensure that the atoms have not had time to escape the trap when they are zapped with an electron beam. |
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| ... mathematics and practical experience support this. However, I'll defer to anyone else on the subject of magnetic transients (if these are pertinent) |
The relevant issue is experience - mathematics is there purely to describe that experience and hopefully provide a structure to generalize it to other situations. Theory serves observation.
I don't know the physics of this setup, nor do I know what type of control structure he's using to do this. It may be just a simple open-loop switch without feedback. By using feedback, it might be possible to speed up the natural transient's settling time, but again I don't know the specifics here. Nor do I know the point of the experiment - many times, experimentalists are focused primarily on getting the experiment to work correctly, not on the purpose of the results.
BTW - I assume these folks, being professors of physics at a major English research university - are well aware of the Heisenberg Uncertainty Principle and Planck's constant. |
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Jerry Erickson
From:
Atlanta,IL 61723
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Glenn Suchan
From:
Austin, Texas
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Posted 5 Jan 2009 1:41 pm
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b0b,
The way I understand it, the Noise Addict article about the amplifier/speaker "experiment" seems to claim an atom is held still, or "frozen" when an amplifier driving a speaker is shut off at a precise time. That time being in between the positive and negative phases a sine wave cycle. This sounds like the article is claiming a cold atom (aka) Bose-Einstein Condensate [BEC] was achieved in this simple procedure. If so, it may be impossible to prove what the article claims without the "usual" array of modern-day laboratory equipment.
Even with my bird-brain knowledge of physics, I know it takes alot more than shuting off an induction field to create the incredibly elusive environment for BEC's (a plasma temperature of very near absolute zero). It takes present day, state-of-the-art research equipment, and BEC's are still not a sure thing. If this wasn't the case, BEC experiments may have be pursued and possibly accomplished as early as the 1920's when Satyendra Nath Bose first theorized about the bizarre quantum state of a "frozen atom". After all, the referenced speaker/amplifier technology was available then. 'Sounds like another "Cold Fusion" fairy tale to me.
In any case, thank-you for linking the article. It was entertaining in a science fiction sort of way. 
Keep on pickin'!
Glenn |
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Glenn Suchan
From:
Austin, Texas
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Posted 5 Jan 2009 1:57 pm
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Disregard my last remarks. I just re-read Dave Mudgett's link to Dr. Murray's research. It appears Professor Murray's experimentation has more to do with creating an "anvil" to hold an atom in a precise target area in order to facilitate high energy bombardment. Bose-Einstein Condensate research deals with studying atoms at a stand-still. In some research labs, this is being taken to the next level by attempting to transport a cold atom from one location to another.
Keep on pickin'!
Glenn |
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Dave Mudgett
From:
Central Pennsylvania and Gallatin, Tennessee
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Posted 5 Jan 2009 5:57 pm
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Yup - the way I read it, they're using the speaker's alternating magnetic field, apparently along with laser beam that changes polarization with the polarity of the magnetic field, to trap the cold atoms for bombardment. The problem is that they need to turn off the magnetic field off to avoid interference, and with a standard (static) magnetic field control scheme, the atom would drift before they could actually bombard it.
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| The alternating [magnetic] field can be used to trap atoms as long as we ensure that the laser beams change polarisation along with it ... |
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Earnest Bovine
From:
Los Angeles CA USA
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Posted 5 Jan 2009 7:35 pm Re: Guitar Amps and Particle Physics
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| b0b wrote: |
From www.noiseaddicts.com:
| Quote: |
When fed with a sine wave, the speaker coils cycle nicely between a positive and negative magnetic field. At the end of each cycle, the positive and negative currents in the coil cancel each other out to produce a neutral magnetic field.
When the power is cut from the amplifier at the precise moment of the end of a cycle, then the atom is held completely still. |
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The atom? Which atom? There are so many to choose from. And why should we care about one atom? |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 5 Jan 2009 8:39 pm
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You're right, Earnest! I think it's time we demanded independent confirmation of his results. If Eric Clapton can't duplicate the experiment, we should assume it's simply a false (post hoc, ergo propter hoc) conclusion.  |
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Tony Prior
From:
Charlotte NC
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Posted 6 Jan 2009 5:09 am
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and yet of course, nobody has yet to ask..
What if there is "NO SOUND" being introduced into the amplifier as it is being turned off.
hence; Eric Clapton has already stopped playing and put his guitar down and turned all the knobs to zero.
Now what are the atoms doing ? |
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Glenn Suchan
From:
Austin, Texas
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Posted 6 Jan 2009 7:11 am
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Dave, Earnest, there's an overwhelming possibility I'm wrong  However, I don't think Professor Murray's research is dealing with a single "cold" atom. I say this because, if it was, they would still be dealing with Bose-Einstein Condensates. Even with BEC's it's difficult to reduce a quantity to as few as 100 atoms. Also, by indicating a "cold" atom, one is speaking of BEC's.
My take on this is (and once again, consider my very uneducated interpretation) the research involves a gas or plasma of a pure element, (in this case, calcium); a power amplifier (several hundred watts or greater) capable of an output of maybe in the 10 to 20 hz range, and a low output impedance (< 2 ohms); driving a coil made of high purity metal.
By using a pure elemental gas or plasma, it wouldn't be necessary to use a single atom to study the effect of a high energy impact, because the particle scatter would be the same as a single atom. Just multiplied by the quantity of atoms targeted. Also, if a single atom were used, a BEC would have to be created; and, unless this single cold atom could be transported (something that is still being researched) the optical table used to induce a BEC would be the target area for bombardment. This would never happen because of equipment damage.
Keep on pickin'!
Glenn |
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Ulric Utsi-Ă…hlin
From:
Sweden
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Posted 6 Jan 2009 9:41 am Atoms...
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| I go for the "string-theory"...McUtsi |
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Dave Mudgett
From:
Central Pennsylvania and Gallatin, Tennessee
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Posted 6 Jan 2009 11:52 am
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| I honestly have no idea how many atom(s) they're dealing with. The articles use the singular and plural at various points. |
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Glenn Suchan
From:
Austin, Texas
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Posted 6 Jan 2009 12:49 pm
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Dave, I hear ya'. That's why I made the earlier comment about the article as a fiction tale.
Honestly, I should've kept my comments to myself, 'cause I am far from an authority on any sort of scientific research. Sometimes I just can't stop from blabberin'. 
Keep on pickin'!
Glenn |
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