Landau–Zener Avoided Crossing

In quantum mechanics, the Landau–Zener formula calculates the probability that a system transitions between energy states when the parameters of its Hamiltonian are varied over time. An avoided crossing occurs when two energy levels approach each other but do not cross, instead repelling each other due to a non-zero coupling between the states.

Experiment

Observe how the coupling strength g and the sweep speed v affect the transition probabilities and the energy gap.

1. Set the Coupling g to different values and observe how the minimum energy gap changes. When g=0, it is a true crossing.
2. Increase the Sweep speed v and observe how the probability of remaining in the initial diabatic state changes. A faster sweep leads to a higher probability of staying in the same diabatic state.
3. Change the Probe time to see the instantaneous energy gap at different points during the sweep.