Comments on: philosophers, physicists, help! http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/ i was uncool before uncool was cool Fri, 30 Jul 2010 21:59:41 +0000 http://wordpress.org/?v=2.3.2 By: Philippe-A http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-20339 Philippe-A Wed, 04 Mar 2009 16:50:42 +0000 http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-20339 "This is not a statement about the limitations of a researcher’s ability to measure particular quantities of a system, but rather about the nature of the system itself." . but then again . http://www.scienceblog.com/cms/quantum-paradox-directly-observed-milestone-quantum-mechanics-19156.html . please note that I don't understand anything about that article “This is not a statement about the limitations of a researcher’s ability to measure particular quantities of a system, but rather about the nature of the system itself.”
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but then again
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http://www.scienceblog.com/cms/quantum-paradox-directly-observed-milestone-quantum-mechanics-19156.html
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please note that I don’t understand anything about that article

]]> By: Marie-Jo http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19985 Marie-Jo Wed, 18 Feb 2009 01:24:02 +0000 http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19985 Holy shit, it actually is pretty clear that way. Mais faut que j'y pense un ti peu plus. Bear with me. :) Holy shit, it actually is pretty clear that way. Mais faut que j’y pense un ti peu plus. Bear with me. :)

]]> By: Philippe-A http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19984 Philippe-A Wed, 18 Feb 2009 01:03:15 +0000 http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19984 So in my example, the concrete wall our wave hit is the beam of light you shed on it, or whatever measurement you're doing. Trying to determine the position of a wave is basically like making it hit that concrete wall. It now has a definite position, but it no longer has a wavelength. Sorry, maybe I'm getting a little too much into this, it's just that explaining it to you was a way for me to understand the process better. I'm tutoring kids in secondaire and even sometimes Cegep, and it's good to be able to answer such questions without too much hesitation. I now understand the HUP and the WPD much better, or at least, what were intuitions became known facts. So in my example, the concrete wall our wave hit is the beam of light you shed on it, or whatever measurement you’re doing. Trying to determine the position of a wave is basically like making it hit that concrete wall. It now has a definite position, but it no longer has a wavelength.

Sorry, maybe I’m getting a little too much into this, it’s just that explaining it to you was a way for me to understand the process better. I’m tutoring kids in secondaire and even sometimes Cegep, and it’s good to be able to answer such questions without too much hesitation. I now understand the HUP and the WPD much better, or at least, what were intuitions became known facts.

]]> By: Philippe-A http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19983 Philippe-A Wed, 18 Feb 2009 00:52:46 +0000 http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19983 Ok we'll take out the math factor, let's use an exemple that might not be totally in sync with quantum mechanics but that still illustrates the phenomenon pretty well. - Suppose you're at the beach and want to measure the speed of waves. - You'll stand in the water and measure the time it takes for two consecutives summit of the wave to hit you. But the wave itself is not the summit that hit you, it's included all allong the two summits. You can't pinpoint it's position. By the way, the summit is a totally arbitrary point of reference, you could choose the bottom of the swell as well since they're just as part of the wave. - The only time this wave has a position is when it is concentrated at a point. For exemple, when the wave hits a concrete wall and all its energy is transfered from the x axis along wich it runs (the horizon line basically) to the y axis (the vertical of the wall it hits). So at this very moment, your wave is all concentrated at a definite x position (the only axis we're interested in for this measurement). It's not just the summit that hits the wall, it's the whole wave, that's why it'll reach higher on that wall then the original summit (twice the horizon to summit distance (amplitude) if I remember well, or base to summit (2*amplitude). When we see an actual wave smashing into a well, it does indeed reach much higher than the tip of the wave itself. - But as it does this, the wavelengt collapses into this definite point which makes it impossible to discuss speed, since speed is defined as the time in takes for the wave to complete a full cycle. There are no cycles anymore, the wave became a point. - In quantum mechanics, instead of speed, they discuss moment, which is the inverse of the wavelenght (1/wavelenght). So when the wavelenght collapses and approaches zero we get 1/0 which is a mathematical impossibility. Sorry, math popped again. - Is that any clearer? - We got to keep in mind that quantum mechanics is not meant to be understood with our newtonian experience of life and frame of reference. Like for instance, when you approach the speed of light, your mass diminuishes. This makes no sense at all to me and I can't wrap my head around it. All I can do is say ... well, Ok then. I'll take your word for it Ok we’ll take out the math factor, let’s use an exemple that might not be totally in sync with quantum mechanics but that still illustrates the phenomenon pretty well.
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Suppose you’re at the beach and want to measure the speed of waves.
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You’ll stand in the water and measure the time it takes for two consecutives summit of the wave to hit you. But the wave itself is not the summit that hit you, it’s included all allong the two summits. You can’t pinpoint it’s position. By the way, the summit is a totally arbitrary point of reference, you could choose the bottom of the swell as well since they’re just as part of the wave.
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The only time this wave has a position is when it is concentrated at a point. For exemple, when the wave hits a concrete wall and all its energy is transfered from the x axis along wich it runs (the horizon line basically) to the y axis (the vertical of the wall it hits). So at this very moment, your wave is all concentrated at a definite x position (the only axis we’re interested in for this measurement). It’s not just the summit that hits the wall, it’s the whole wave, that’s why it’ll reach higher on that wall then the original summit (twice the horizon to summit distance (amplitude) if I remember well, or base to summit (2*amplitude). When we see an actual wave smashing into a well, it does indeed reach much higher than the tip of the wave itself.
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But as it does this, the wavelengt collapses into this definite point which makes it impossible to discuss speed, since speed is defined as the time in takes for the wave to complete a full cycle. There are no cycles anymore, the wave became a point.
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In quantum mechanics, instead of speed, they discuss moment, which is the inverse of the wavelenght (1/wavelenght). So when the wavelenght collapses and approaches zero we get 1/0 which is a mathematical impossibility. Sorry, math popped again.
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Is that any clearer?
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We got to keep in mind that quantum mechanics is not meant to be understood with our newtonian experience of life and frame of reference. Like for instance, when you approach the speed of light, your mass diminuishes. This makes no sense at all to me and I can’t wrap my head around it. All I can do is say … well, Ok then. I’ll take your word for it

]]> By: Martin http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19970 Martin Tue, 17 Feb 2009 14:26:33 +0000 http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19970 Okay, je vais relire ton texte et repenser à tout ça. :) Okay, je vais relire ton texte et repenser à tout ça. :)

]]> By: Martin http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19968 Martin Tue, 17 Feb 2009 13:58:21 +0000 http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19968 Je pense que je t'ai perdue quelque part au deuxième paragraphe. :) Je pense que je t’ai perdue quelque part au deuxième paragraphe. :)

]]> By: Marie-Jo http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19960 Marie-Jo Tue, 17 Feb 2009 03:45:56 +0000 http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19960 Still sounds like just math to me, but it looks like you're right. Someone on the Wikipedia Reference Desk asked the same question and got the following: http://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Archives/Science/2008_October_14#Is_Heisenburg.27s_Uncertainty_Principle_really_universal.3F Cheers! Still sounds like just math to me, but it looks like you’re right. Someone on the Wikipedia Reference Desk asked the same question and got the following: http://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Archives/Science/2008_October_14#Is_Heisenburg.27s_Uncertainty_Principle_really_universal.3F

Cheers!

]]> By: Philippe-A http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19957 Philippe-A Tue, 17 Feb 2009 00:48:46 +0000 http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19957 (can you please delete the first duplicate of this comment, I forgot to proof-read, tnx). I’m not 100% sure of what I’m saying as I’m not very knowledgeable of quantum mechanics… or newtonian for that matter. But the theoritical way to measure the speed of a wave, regarless of technical limitations, is to measure the time it takes for the wave to pass thru a point and complete a full cycle, summit to summit, for instance. But when you do that, you’re considering your wave/particle as a wave. So that manifestation you’re studying is no longer a dot in the space, it’s information is encrypted throughout the whole wave, from summit to summit. It doesn’t have a position, the wave itself is both the beggining and the end of that cycle. Ok.. i paused to do a bit of fact checking, as I was starting to doubt myself even more, but this seems to be the modern explanation of HUP. From the Wave-Particle Duality article on Wikipedia “In fact, the modern explanation of the uncertainty principle, extending the Copenhagen interpretation first put forward by Bohr and Heisenberg, depends even more centrally on the wave nature of a particle: Just as it is nonsensical to discuss the precise location of a wave on a string, particles do not have perfectly precise positions; likewise, just as it is nonsensical to discuss the wavelength of a “pulse” wave traveling down a string, particles do not have perfectly precise momenta (which corresponds to the inverse of wavelength). Moreover, when position is relatively well defined, the wave is pulse-like and has a very ill-defined wavelength (and thus momentum). And conversely, when momentum (and thus wavelength) is relatively well defined, the wave looks long and sinusoidal, and therefore it has a very ill-defined position.” (can you please delete the first duplicate of this comment, I forgot to proof-read, tnx).

I’m not 100% sure of what I’m saying as I’m not very knowledgeable of quantum mechanics… or newtonian for that matter.

But the theoritical way to measure the speed of a wave, regarless of technical limitations, is to measure the time it takes for the wave to pass thru a point and complete a full cycle, summit to summit, for instance. But when you do that, you’re considering your wave/particle as a wave. So that manifestation you’re studying is no longer a dot in the space, it’s information is encrypted throughout the whole wave, from summit to summit. It doesn’t have a position, the wave itself is both the beggining and the end of that cycle.

Ok.. i paused to do a bit of fact checking, as I was starting to doubt myself even more, but this seems to be the modern explanation of HUP.

From the Wave-Particle Duality article on Wikipedia

“In fact, the modern explanation of the uncertainty principle, extending the Copenhagen interpretation first put forward by Bohr and Heisenberg, depends even more centrally on the wave nature of a particle: Just as it is nonsensical to discuss the precise location of a wave on a string, particles do not have perfectly precise positions; likewise, just as it is nonsensical to discuss the wavelength of a “pulse” wave traveling down a string, particles do not have perfectly precise momenta (which corresponds to the inverse of wavelength). Moreover, when position is relatively well defined, the wave is pulse-like and has a very ill-defined wavelength (and thus momentum). And conversely, when momentum (and thus wavelength) is relatively well defined, the wave looks long and sinusoidal, and therefore it has a very ill-defined position.”

]]> By: Philippe-A http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19955 Philippe-A Tue, 17 Feb 2009 00:42:54 +0000 http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19955 I'm not 100% of what I'm saying as I'm not very knowledgeable of quantum mechanics... or newtonian for that matter. But the theoritical way to measure the speed of a wave, regarless of technical limitations, is to measure the time it takes for the wave to pass thru a point and complete a full cycle, summit to summit, for instance. But when you do that, you're considering your wave/particle as a wave. So that manifestation you're studying is no longer a dot in the space, it's information is encrypted throughout the whole wave, from summit to summit. It doesn't have a position, the wave itself is both the beggining and the end of that cycle. I was fact checking, and this seems to be the modern explanation of HUP. From the Wave-Particle Duality article on Wikipedia "In fact, the modern explanation of the uncertainty principle, extending the Copenhagen interpretation first put forward by Bohr and Heisenberg, depends even more centrally on the wave nature of a particle: Just as it is nonsensical to discuss the precise location of a wave on a string, particles do not have perfectly precise positions; likewise, just as it is nonsensical to discuss the wavelength of a "pulse" wave traveling down a string, particles do not have perfectly precise momenta (which corresponds to the inverse of wavelength). Moreover, when position is relatively well defined, the wave is pulse-like and has a very ill-defined wavelength (and thus momentum). And conversely, when momentum (and thus wavelength) is relatively well defined, the wave looks long and sinusoidal, and therefore it has a very ill-defined position." I’m not 100% of what I’m saying as I’m not very knowledgeable of quantum mechanics… or newtonian for that matter.

But the theoritical way to measure the speed of a wave, regarless of technical limitations, is to measure the time it takes for the wave to pass thru a point and complete a full cycle, summit to summit, for instance. But when you do that, you’re considering your wave/particle as a wave. So that manifestation you’re studying is no longer a dot in the space, it’s information is encrypted throughout the whole wave, from summit to summit. It doesn’t have a position, the wave itself is both the beggining and the end of that cycle.

I was fact checking, and this seems to be the modern explanation of HUP.

From the Wave-Particle Duality article on Wikipedia

“In fact, the modern explanation of the uncertainty principle, extending the Copenhagen interpretation first put forward by Bohr and Heisenberg, depends even more centrally on the wave nature of a particle: Just as it is nonsensical to discuss the precise location of a wave on a string, particles do not have perfectly precise positions; likewise, just as it is nonsensical to discuss the wavelength of a “pulse” wave traveling down a string, particles do not have perfectly precise momenta (which corresponds to the inverse of wavelength). Moreover, when position is relatively well defined, the wave is pulse-like and has a very ill-defined wavelength (and thus momentum). And conversely, when momentum (and thus wavelength) is relatively well defined, the wave looks long and sinusoidal, and therefore it has a very ill-defined position.”

]]> By: Marie-Jo http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19950 Marie-Jo Mon, 16 Feb 2009 21:28:57 +0000 http://www.lightspeedchick.com/things-in-general/philosophers-physicists-help/#comment-19950 But isn't this too a result of measurement: "When the position of a particle is measured, the particle's wavefunction collapses and the momentum does not have a definite value". I've never seen an explanation of the HUP that doesn't involve measurement or observation. But isn’t this too a result of measurement: “When the position of a particle is measured, the particle’s wavefunction collapses and the momentum does not have a definite value”. I’ve never seen an explanation of the HUP that doesn’t involve measurement or observation.

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