Rabi oscillations refer to the oscillatory behavior of a quantum system when it is subjected to an external electromagnetic field. This phenomenon occurs when a two-level quantum system, such as an atom or a qubit, interacts with a resonant light field. The system alternates between its two energy states, leading to periodic transitions that can be observed as changes in population between the states. The frequency of these oscillations, known as the Rabi frequency, depends on the strength of the external field and the energy difference between the two states. Rabi oscillations are fundamental in various applications, including quantum computing and atomic physics, as they provide insights into the dynamics of quantum systems.