Table of Contents
What does identical mean in physics?
In quantum mechanics, identical particles (also called indistinguishable or indiscernible particles) are particles that cannot be distinguished from one another, even in principle.
Are fermions distinguishable?
Fermions, bosons, and classical particles obey different probability laws. Classical particles are distinguishable. The state that has particle 1 in box 1 and particle 2 in box 2 differs from the state that has particle 2 in box 1 and particle 1 in box 2. Bosons and Fermions are indistinguishable.
Are photons distinguishable?
Of course, the photons are distinguishable because they emit different colors. The researchers use the source of this natural difference—the local electric field—as a knob that changes the dye molecule’s emitted wavelength.
Under what circumstances may identical particles be regarded as distinguishable?
Two particles are said to be identical if all their intrinsic properties (mass, spin, charge, etc.) are exactly the same: no experiment can distinguish one from the other.
Are bosons distinguishable?
Why can’t we distinguish between two particles in an atom?
What people often mean is that in the atom, one cannot follow electrons in time to maintain the knowledge of which is which. In this sense, in classical physics identical particles are distinguishable, but in quantum theory identical particles are indistinguishable, because we cannot look and track the electron in the atom.
What is the meaning of identical electrons in daily life?
Indistinguishable in daily life means pretty much the same thing. In case of electrons, we call them identical because they have the same charge and mass and possibly other parameters (spin…) for similar reasons as we call two xerox copies identical.
What is the computational relevance of the distinction between two particles?
The computational relevance of the distinction is that permutations of (in)distinguishable particles (don’t) count towards the weighting factor. For an expanded discussion see my article at PhysicsForums.