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Superposition
In quantum mechanics, superposition describes how two (or more) quantum states can be added together to produce another valid quantum state.
Explanation
It means that every quantum state can be represented as a sum of two or more other distinct states.
Decay time
Quantum superpositions do not last forever. For an unstable particle the superposition |ψ⟩ would decay to either |1⟩ or |2⟩ in an everage time τ of the order
where
ℏ Reduced Planck constant EG Gravitational self-energy
Example 1
An electron in the state |1⟩ + i |2⟩ is in a quantum superposition of the states |1⟩ and |2⟩.