Firedragon52 Posted September 8, 2004 Share Posted September 8, 2004 If we use De Broglie's equation for waves: http://theory.uwinnipeg.ca/physics/quant/node6.html Does this mean that if humans move at a certain velocity, that they will give off a detectable light? Link to comment Share on other sites More sharing options...
pulkit Posted September 8, 2004 Share Posted September 8, 2004 Given the mass of a human being the wavelength is of the order of [MATH]10^{-30}[/MATH] which is practically negligible. Plus there is a lot of difference between matter waves and EM-waves, light does not come into the picture. Link to comment Share on other sites More sharing options...
Firedragon52 Posted September 8, 2004 Author Share Posted September 8, 2004 Given the mass of a human being the wavelength is of the order of [MATH]10^{-30}[/MATH] which is practically negligible. Plus there is a lot of difference between matter waves and EM-waves' date=' light does not come into the picture.[/quote']I would still imagine that there must be some type of device that would be able to detect these negligible waves and record them. Is there? On another note, I find it interesting that for this formula, matter with small masses create more detectable waves than matter with large masses. This seems counterinituitive. Why is this the case? As for matter waves, can we detect these? Link to comment Share on other sites More sharing options...
pulkit Posted September 8, 2004 Share Posted September 8, 2004 I would still imagine that there must be some type of device that would be able to detect these negligible waves and record them. Is there? No. Its just too small. On another note, I find it interesting that for this formula, matter with small masses create more detectable waves than matter with large masses. This seems counterinituitive. Why is this the case? I would think it is intuitive. Consider it in the light of the Heisenberg principle of uncertainty. As for matter waves, can we detect these? Yes of course ! Check out the Davisson-Germer experiment, which first established their exsistance. It is based on diffraction of electron waves. Link to comment Share on other sites More sharing options...
Firedragon52 Posted September 8, 2004 Author Share Posted September 8, 2004 On this website: http://www.colorado.edu/physics/2000/quantumzone/debroglie.html It mentions: Think about what the wavelength of the bowling ball would be. According to de Broglie, the wavelength is equal to Planck's constant divided by the object's momentum; Planck's constant is very, very, very tiny, and the momentum of a bowling ball, relatively speaking, is huge. If you had abowling ball with a mass of, say, one kilogram, moving at one meter per second, its wavelength would be about a septillionth of a nanometer. This is so ridiculously small compared to the size of the bowling ball itself that you'd never notice any wavelike stuff going on; that's why we can generally ignore the effects of quantum mechanics when we're talking about everyday objects. It's only at the molecular or atomic level that the waves begin to be large enough (compared to the size of an atom) to have a noticeable effect. It kinda answers my questions of why a humans matter waves are neglible. But from de Broglie's equation: http://theory.uwinnipeg.ca/physics/quant/node6.html I still don't understand why a human being, at the right momentum, STILL wouldn't be able to produce a wave comparable to a particles (momentum) to produce a detectable wave. Is it possible, at the right momentum, for humans to produce a detectable matter wave. Link to comment Share on other sites More sharing options...
swansont Posted September 8, 2004 Share Posted September 8, 2004 I would still imagine that there must be some type of device that would be able to detect these negligible waves and record them. Is there? On another note' date=' I find it interesting that for this formula, matter with small masses create more detectable waves than matter with large masses. This seems counterinituitive. Why is this the case? As for matter waves, can we detect these?[/quote'] To measure someone's position to better than a part in 1030 implies, according to the Heisenberg uncertainty principle, knowing the position to about 0.1 micron (assuming mass is of order 100kg). Can you keep that still, to be able to make that measurement? The smaller the mass, the easier it is to know the momentum to a given precision. Matter waves - yes, as has been stated. Electron microscopes. Atom interferometers, too (my graduate work involved building part of an atom interferometer) Link to comment Share on other sites More sharing options...
Firedragon52 Posted September 8, 2004 Author Share Posted September 8, 2004 Electron microscopes. Atom interferometers, too (my graduate work involved building part of an atom interferometer)What exactly is an atom interferometer? Link to comment Share on other sites More sharing options...
Guest Rhino Posted October 17, 2004 Share Posted October 17, 2004 well I have a question about de Broglie's equation according to it, which would have the large wavelength, a slow-moving proton or a fast-moving golf ball? Explaing your answer please reply ASAP Link to comment Share on other sites More sharing options...
swansont Posted October 17, 2004 Share Posted October 17, 2004 What exactly is an atom interferometer? Sorry - I missed this. An atom interferometer is a device that, as the name implies, interferes atoms. You split an atomic beam into two parts and then later recombine them. If one of the two parts undergoes any kind of interaction that changes the energy (and thus momentum), there will be a phase difference in the waves where they recombine (or the phase will be the same at some different point). The one I worked on was to use gratings to cause diffraction to split the beams and then recombine them. Here is a picture of one (from a different research group - it's the first diagram I could find) Link to comment Share on other sites More sharing options...
swansont Posted October 17, 2004 Share Posted October 17, 2004 well I have a question about de Broglie's equationaccording to it' date=' which would have the large wavelength, a slow-moving proton or a fast-moving golf ball? Explaing your answer please reply ASAP[/quote'] Explain my answer? It's not my HW question! deBroglie wavelength is h/p = h/mv You should be able to figure it out from that Link to comment Share on other sites More sharing options...
Firedragon52 Posted October 27, 2004 Author Share Posted October 27, 2004 Sorry - I missed this. Don't worry I got. Thanks. Link to comment Share on other sites More sharing options...
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