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classes:2009:fall:phys4101.001:q_a_0914 [2009/09/14 19:33] – ykclasses:2009:fall:phys4101.001:q_a_0914 [2009/09/20 17:41] (current) – x500_vinc0053
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 If i understand the question, If i understand the question,
  i believe this correspondence is shown on page 19. Figure 1.7 shows a wave that has no clean position in time and 1.8 shows a pulse which has position in time, but a poorly definable wavelength.   i believe this correspondence is shown on page 19. Figure 1.7 shows a wave that has no clean position in time and 1.8 shows a pulse which has position in time, but a poorly definable wavelength. 
 +
 +===The Doctor 21:50 9/14/09===
 +You could probably say that a single pulse is a poorly defined wave in that it's wavelength is ill-defined.  But then you would be saying that a regular periodic wave is a poorly defined wave in that you don't know it's position.  I actually don't remember seeing "poorly defined wave" used anywhere and it may be an unimportant definition.  Mostly you want to just be looking at the poorly defined wavelength/position stuff.
  
 ==== Dark Helmet 12:33am 09/13 ==== ==== Dark Helmet 12:33am 09/13 ====
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 Relating it to the Fourier series should make it a bit more clear.  A real problem that hopefully helps to visualize it is describing a specific wave function, say a square wave, in terms of the summation of many sinusoidal waves.  This would be a real world example of sound waves that works for describing the quantum mechanical view of particles as well. Relating it to the Fourier series should make it a bit more clear.  A real problem that hopefully helps to visualize it is describing a specific wave function, say a square wave, in terms of the summation of many sinusoidal waves.  This would be a real world example of sound waves that works for describing the quantum mechanical view of particles as well.
 +
 +===vinc0053 09/20 17:35===
 +I like to think of the simplest case where you know the wave is only in the ground state.  Then you have <math>c_1</math> equal to 1 and all other constants equal to zero.  Then you can add the next state by, for example, having <math>c_1, c_2</math> hold values reflecting their proportional make-up, with all other constants equal to zero.
  
 ====John Galt 11:02 9/14/09==== ====John Galt 11:02 9/14/09====
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 What causes the uncertainty in position of a photon? Since the wave function (edit: probability function) does not spread out over time, I would assume that it is the same as it was during its original emission. Does it reflect an inability to measure the time of emission properly, or just the lack of resolution of devices measuring the position of photons? I understand that position is uncertain due the velocity of the photon, but it seems to me that since the function does not spread out over time, an accurate enough recording of the time of emission would lessen the uncertainty in the position of a photon (narrowing the probability function) at any given point. Is this a reasonable assumption? What causes the uncertainty in position of a photon? Since the wave function (edit: probability function) does not spread out over time, I would assume that it is the same as it was during its original emission. Does it reflect an inability to measure the time of emission properly, or just the lack of resolution of devices measuring the position of photons? I understand that position is uncertain due the velocity of the photon, but it seems to me that since the function does not spread out over time, an accurate enough recording of the time of emission would lessen the uncertainty in the position of a photon (narrowing the probability function) at any given point. Is this a reasonable assumption?
  
-== Spherical Chicken 14:13 9/14/09==+=== Spherical Chicken 14:13 9/14/09===
  
 I think it would be fair to say that if photons had a set energy, and could not be energized to higher states, they would not be terribly uncertain as we would not change them (by adding energy) in observation.  Viewing a photon by using a photon wouldn't add energy to it.   I think it would be fair to say that if photons had a set energy, and could not be energized to higher states, they would not be terribly uncertain as we would not change them (by adding energy) in observation.  Viewing a photon by using a photon wouldn't add energy to it.  
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 is this correct? Or am I as well misunderstanding the concept? is this correct? Or am I as well misunderstanding the concept?
 +
 +==== time to move on ====
 +It's time to move on to the next Q_A: [[Q_A_0916]]
 +
classes/2009/fall/phys4101.001/q_a_0914.1252974818.txt.gz · Last modified: 2009/09/14 19:33 by yk

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