Atomic coherence

During Rabi flopping the electron oscillates between the ground and excited states and can be described by a continuous rotation around the Bloch sphere.

In practice, interactions between the system and the environment introduce a phase offset in the Rabi oscillation between the two levels, causing "decoherence".

In actual experiments ambient magnetic field noise and thermal heating from collisions between atoms cause decoherence faster than random spontaneous emission and are the dominant uncertainties when running atomic clocks or trapped ion quantum computers.

Atomic coherence is essential in research on several effects, such as electromagnetically induced transparency (EIT), lasing without inversion (LWI), stimulated raman adiabatic passage (STIRAP) and nonlinear optical interaction with enhanced efficiency.

Atomic systems demonstrating continuous superradiance exhibit long coherence time, a property shared with lasers.

Rabi flopping between the and energy states in . This example shows high fidelity Rabi flopping on the clock transition with little decoherence.