Can identical particles be distinguishable?

In summary, the conversation discusses the possibility of having identical quantum particles that are distinguishable, with the conclusion being that this is not possible due to the nature of quantum mechanics. The conversation also touches on the possibility of gaseous atoms behaving like a Fermi-Dirac or Bose-Einstein gas under certain conditions, with the understanding that these distributions are more fundamental. The superfluid phase transition of liquid helium is mentioned as a potential example of this behavior.
  • #1
Twigg
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Is it possible to have identical quantum particles that are distinguishable? By identical, I only mean that all particle properties like mass, spin, charge, etc., are identical. My guess would be no because the only thing that could tell the two apart is their trajectories, but their wavefunctions may overlap, which in my mind ought to make them indistinguishable. Is that anywhere in the ballpark of the right way to think about it?
On the other hand, is it theoretically possible to make gaseous atoms, as would normally obey the Maxwell-Boltzmann distribution, instead behave like a Fermi-Dirac or Bose-Einstein gas under the right conditions and on the right energy scales? Is there a well-known example of this? Would the superfluid phase transition of liquid helium be a valid instance?
 
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  • #2
Twigg said:
Is it possible to have identical quantum particles that are distinguishable?
No, by definition of "identical" and quantum mechanics.
Twigg said:
but their wavefunctions may overlap
You cannot consider single-particle wave functions any more, you have to take a single wave function to describe both, and there is no "first particle here, second here" any more.
Twigg said:
On the other hand, is it theoretically possible to make gaseous atoms, as would normally obey the Maxwell-Boltzmann distribution, instead behave like a Fermi-Dirac or Bose-Einstein gas under the right conditions and on the right energy scales?
It is impossible to avoid this. FD and BE are the more fundamental distributions, for large temperatures they both can get approximated by Maxwell-Boltzmann.
 
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Makes sense. Thanks!
 

1. Can identical particles be distinguishable?

Yes, identical particles can be distinguishable. While all particles of the same type have the same physical properties, they can still be identified by their unique quantum states, such as spin or energy levels.

2. How can identical particles be distinguished?

Identical particles can be distinguished by their unique quantum states, such as spin, energy levels, or wave functions. These properties allow for differentiation between particles of the same type.

3. Why is it important to distinguish between identical particles?

Distinguishing between identical particles is important in fields such as quantum mechanics, where the state of a particle can affect its behavior and interactions with other particles. Identifying and tracking individual particles is crucial for understanding and predicting complex systems.

4. Can identical particles be labeled or tagged to make them distinguishable?

Yes, identical particles can be labeled or tagged to make them distinguishable. This can be done by using techniques such as quantum entanglement or by physically marking the particles with unique identifiers.

5. Is it possible for identical particles to become distinguishable over time?

Yes, it is possible for identical particles to become distinguishable over time. This can occur through processes such as decoherence, where the quantum states of particles become entangled with their surroundings and can no longer be distinguished from one another.

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