Rabi oscillations refer to the periodic transitions between two quantum states of a system — such as an electron’s spin states or energy levels in an atom — when it is subjected to an external oscillating field, typically an electromagnetic wave like a microwave or laser.
Named after physicist Isidor Rabi, this phenomenon occurs when the frequency of the external field is resonant (or nearly resonant) with the energy difference between the two quantum states. Under such conditions, the system doesn’t just randomly jump between states; instead, it coherently oscillates between them over time.
Key features of Rabi oscillations include:
- Population transfer: The probability of finding the system in one state or the other varies sinusoidally with time.
- Rabi frequency: The rate at which these oscillations occur, which depends on the strength of the interaction between the quantum system and the external field.
- Quantum control: By controlling the duration and strength of the field, one can precisely manipulate the system’s state — an essential principle in quantum computing and quantum information processing.
Rabi oscillations are fundamental to quantum optics, atomic clocks, and quantum computing, where they are used to perform operations on qubits and control quantum systems with high precision.