What is the largest size for identical particles?

[scope]

hi,

I would like to know how big can be 2 identical particles?
can they be atoms, molecules, or even much larger than this?

in the extreme case, can they be 2 identical cars for example?

can we also say that any 2 electrons in the universe are identical particles?

I would be grateful for your reply!

 

[mathman]

Your question is a little confusing. However on the particle level, any 2 particles of the same kind are identical. When it comes to atoms, etc. these are combinations. As long as the constituents are the same, they are identical. However at the molecular level things get more complicated, since arrangements matter.

 

[G01]

can we also say that any 2 electrons in the universe are identical particles?

In regards to this part of your question, I think there is a quote from David Griffith's (or was it Schroeder) that I'll paraphrase:

It does not make sense to talk about this electron or that electron. The best we can do is talk about an electron.

All fundamental particles one anyone type are entirely indistinguishable from one another. There is no way to "mark" one electron to set it apart from the others.

 

[Avodyne]

in the extreme case, can they be 2 identical cars for example

Yes, provided they are in the same "quantum state".

 

[DaveC426913]

in the extreme case, can they be 2 identical cars for example?

The identicality of a substance breaks down pretty quickly before even you get out of microscopic scales.

Even crystals, the most highly ordered of macro objects, are full of flaws at the microscopic level. And regular materials such as even the thinnest of metals are much more disordered than the most disordered crystals.

It is the Holy Grail of Materials Science to produce macro-scale substances that are virtually flaw-free.