Question

What is the meaning and significance of superposition in quantum mechanics?

Answer 1

Hint : Superposition is defined as the ability of a quantum system to be present in multiple states at the same time until it is measured. Superposition principle applies to waves in quantum mechanics. Waves have amplitude and phase and they add linearly to result in a constructive or destructive interference. If two waves cross each other’s paths, then the places at which the crest of one wave aligns with the crest of another wave will lead to an increased amplitude or lead to constructive interference.

Complete Step By Step Answer:
Quantum system evolves through a coherent superposition of states and an initial state turns into a superposition of states with relative weight factor changing with time in a continuous manner. Survival probability of the evolving system is the probability of final measurement in finding a system in the initial state after it is allowed to evolve for a certain time period $T$ . If the time is not very short, then the survival probability decays exponentially with respect to $T$ . If a quantum superposition is more macroscopic, then it is more likely to involve more objects.

Note :
Remember that if a small quantum system, say the photon, is coupled to larger system, the movable mirror, then the existence of the quantum superposition of states of the larger system is verified by observing the disappearance and reappearance of interference of states of the small system because the large system is driven into superposition of states and returns to its initial state.