| From: Mick | 19/03/2001
13:43:13 |
| Subject: more QM Double Slit | post id:
258684 |
| My understanding of double slit
interference for electrons is: the prob of finding an electron somewhere
is determined by the Schrod. Eqn of the electron. The SE is wave function
- it is the SE which interferes beyond the dbl slit causing the
characteristic interference fringes. Can the other properties of the electron interfere in a similar way. For example, could you do a velocity (or momentum) analogue of the double slit experiment - eg take an electron beam (I assume if you measured the velocity of the electrons you would get some sort of distribution around a mean value. Pass the electron beam thru some material that only transmits particles at 2 specific (very close) velocities. Now measure and plot the velocity distribution of the transmitted electrons - would you see a fringe pattern? If true, then could you also see interference between different sets of variables - does this somehow tie in with quantum uncertainty? Thanks | |
| From: Chris (Avatar) | 19/03/2001
13:53:43 |
| Subject: re: more QM Double Slit | post id:
258699 |
It's actually the norm of the schroedinger wavefunction squared: ½y½2 where y is the wavefunction. In the two slit experiment for electrons, it is not that some or other property of the electron is doing the interfering to create the interference fringes - the electrons actually act as waves rather than particles (depending on how you are detecting them) and interfere with themselves. | |
| From: tritium ® | 19/03/2001
13:53:52 |
| Subject: re: more QM Double Slit | post id:
258700 |
| yes, you could easily do a
momentum interference pattern however let me redefine something for you... you say the prob of finding an electron somewhere this implies that an electron is a point particle and actually exists in the place where you find it it should be the prob of detecting an electron somewhere which means we get a reading as if the electron was at this position, but know nothing about the true make up of the electron | |
| From: Chris (Avatar) | 19/03/2001
13:54:51 |
| Subject: re: more QM Double Slit | post id:
258702 |
That should read: It's actually the norm of the schroedinger wavefunction squared which represents the probability density. | |
| From: Mick | 19/03/2001
14:06:29 |
| Subject: re: more QM Double Slit | post id:
258726 |
| thanks tritium and
chris what about the part about different properties interfering with each other? | |
| From: John Devers ® | 19/03/2001
14:43:31 |
| Subject: re: more QM Double Slit | post id:
258792 |
| Here is the link to the last
thread for those who wish to read more. Try Here | |
| From: tritium ® | 19/03/2001
14:44:18 |
| Subject: re: more QM Double Slit | post id:
258793 |
| quantum uncertainty, also known
as heisenburg uncertainty principle, states that there will always be some
uncertainty in the product of the position and momentum measurement. the
more certain you become of the position, the more uncertain you become of
the momentum. you can find only one of them exactly, but then the other is
completelly unknown. this isn't just a measuring thing however, but is quantum mechanical in nature. the wavefunction of a particle can be described as the sum of many waves of the same frequency. if you have certain amplitudes of these waves, then you can get a localised wave. one that is zero pretty much everywhere except in a small region. so your uncertainty in the position is the size of that region and your uncertainty in the momentum is how much the frequency varies between the waves the most dominantly make up the localised wave. if you know the momentum exactly, then there is only one frequency contributing, but this means we have a sine wave that streaches of to infinity. | |