The discussion revolves around the possibility of tagging or tracking a single atom in a gas composed of identical atoms. Participants explore the feasibility of distinguishing one atom from others, either through isotopic differences or other quantum properties.
Participants express differing views on the feasibility of tracking identical atoms, with some supporting the use of isotopes while others challenge the possibility of distinguishing identical atoms through quantum properties. The discussion remains unresolved regarding the methods and implications of tracking single atoms.
Limitations include the dependence on definitions of distinguishability in quantum mechanics and the potential for decoherence affecting the ability to track atoms over time.
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.