Identical particle / indistinguishable hability

We know very well , in nature have large number of many body system.

There are two main categories of identical particles:

1.bosons:-
       which can share quantum states,

2.fermions :-
       which do not share quantum states as described by the Pauli exclusion principle.

identical particle theory are not limited to elementary particles such as electrons , subatomic particles , like as atomic nuclei , and as well as atoms , quasiparticles behave identical particles .

There is large number of molecules in material , similarly there is large number of atoms in molecules , and there is larger numbers of electron in atoms , large number of nucleons in nucles. 

     We can't distinguish between electron - electron in atom , and nucleons- nucleons inside the nucles . 

We can't distinguish between which electron first and which electron is second in electron-electron scattering Experiment's. So these types of particle are known as identical particle and this property of particle is known as indistinguish Hability. 

We can consider examples in geometry system:

     

● Square

          If we rotate square by an angle 90° then we can't distinguish between squire's .

● Equaletrial triangle

          If we rotate Equaletrial triangle an angle 120° then we can't distinguish between Equaletrial triangle's