What Happens to the Wave Function When the Size of a Quantum Well Doubles?

In summary, the problem involves an infinite quantum well with size L and a particle with mass m inside it. The size of the well is suddenly doubled and the question is to find the wave function at a later time t. The relevant equations are given for the wave function and energy. To solve this problem, one must find the coefficients cn for the superposition of states in the 2L well and consider the time-evolution of these states. The initial state is most likely the ground state, but the context of the problem may affect the answer.
  • #1
chaotic
18
0

Homework Statement



there is a infinite quantum well with size L and there is a particle in it with mass m. suddenly the size of the quantum well is doubled. What will be the wave function at a later time t ?

Homework Equations



ψ= [itex]\sqrt{2/L}[/itex] sin (n pi x / L)

E = n^2 pi^2 h^2 / 2mL^2

The Attempt at a Solution



do we need to find cn again with 2L ?
 
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  • #2
Yes.
I'd normally do this by expressing the initial state of the particle, in the 1L well, in terms of a superposition of states of the final 2L well... then finding the time-evolution of those states.

I'd have expected the initial state to be a specified n state (i.e. the ground state).

A lot depends on context - eg.
If there is a mechanism for decay present, then the question could be answered in terms of the energy lost in the decay from initial to final states. (Otherwise the system remains in a composite state until some measurement of energy is made.)
 

FAQ: What Happens to the Wave Function When the Size of a Quantum Well Doubles?

What is the "particle in a box" model?

The particle in a box model is a simplified theoretical scenario in which a particle is confined to a box and cannot escape its boundaries. This model is often used in quantum mechanics to understand the behavior of particles in a confined space.

How does the size of the box affect the particle's behavior?

The size of the box directly affects the energy levels and wavelengths of the particle. As the box size decreases, the energy levels increase and the wavelength of the particle becomes shorter.

Can the particle's size be changed in the box model?

No, in the particle in a box model, the size of the particle is assumed to be constant. The only variable that can be changed is the size of the box in which the particle is confined.

What happens to the particle when the box size is decreased?

When the box size is decreased, the energy levels of the particle increase and the probability of finding the particle in certain regions of the box also changes. This can lead to a change in the behavior of the particle and potentially affect its interactions with other particles.

How does the concept of "quantization" relate to the particle in a box model?

The concept of quantization, which states that certain properties of particles can only take on discrete values, is closely related to the particle in a box model. In this model, the energy levels of the particle are quantized, meaning they can only take on specific values determined by the size of the box. This is a fundamental principle in quantum mechanics and is demonstrated in the particle in a box model.

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