f95toli said:Well, you can "tag" atoms by simply using different isotopes. This is used for example in PET scans (using e.g. oxygen 15, "normal oxygen" being oxygen 16).
At least in principle it should therefore be possible to track a single atom (using e.g. fluoresence, assuming the different isotopes have slightly shifted energy levels) in a gas.
learningphysics said:Thanks f95toli. Is there any technique by which atoms of exactly the same kind can be tracked... not using isotopes...
What I'm getting at is... would it be possible to number the different atoms in a gas... is there perhaps some quantum level property that can be given to one atom that distinguishes it from the rest.
Probably not for very long. Sure, you could prepare one molecule in a certain state different from all the rest, but that state would probably decohere quickly.learningphysics said:Thanks f95toli. Is there any technique by which atoms of exactly the same kind can be tracked... not using isotopes...
What I'm getting at is... would it be possible to number the different atoms in a gas... is there perhaps some quantum level property that can be given to one atom that distinguishes it from the rest.
One of the cornerstones of quantum physics is the wave nature of matter. It explains experimentally observed effects like interference and diffraction, occurring when an object moves from one place to another along several indistinguishable ways simultaneously. The wave nature disappears when the individual ways are distinguishable. In this case, the particle nature of the object becomes visible. To determine the particle nature quantitatively, the way of the object has to be measured. Here, large progress has been made recently with new techniques, enabling one to investigate single moving atoms in a controlled manner.