- Rabi cycle
In
physics , the Rabi cycle is the cyclic behaviour of atwo-state quantum system in the presence of an oscillatory driving field. A two-state system has two possible states, and if they are notdegenerate energy level s the system can become "excited" when it absorbs aquantum of energy.The effect is important in
quantum optics ,nuclear magnetic resonance andquantum computing . The term is named in honour ofIsidor Isaac Rabi .When an
atom (or some othertwo-level system ) is illuminated by a coherent beam ofphoton s, it will cyclically absorb photons and re-emit them bystimulated emission . One such cycle is called a Rabi cycle and the inverse of its duration theRabi frequency of the photon beam.This mechanism is fundamental to quantum optics. It can be modelled using the
Jaynes-Cummings model and theBloch vector formalism.For example, in a two-state atom (an atom in which an electron can either be in the excited or ground state), the probability of finding the atom in the excited state is found from the Bloch equations to be: c_b(t)|^2=cos(omega t)^2 where omega is the Rabi frequency.
More generally, one can consider a system where the two levels under consideration are not energy eigenstates. Therefore if the system is initialized in one of these levels, time evolution will make the population of each of the levels oscillate with some characteristic frequency, whose
angular frequency [ [http://www.rp-photonics.com/rabi_oscillations.html Encyclopedia of Laser Physics and Technology - Rabi oscillations, Rabi frequency, stimulated emission ] ] is also known as the Rabi frequency.Links
* http://www.itp.tu-berlin.de/menue/lehre/owl/quantenmechanik/zweiniveau/parameter/en/ A Java applet that visualizes Rabi Cycles of two-state systems (laser driven).
* http://www.itp.tu-berlin.de/menue/lehre/owl/quantenmechanik/elektron-phonon-wechselwirkung/parameter/en/ extended version of the applet. Includes electron phonon interaction.Notes
ee also
*
Atomic coherence
*Bloch sphere
*Laser pumping
*Optical pumping
*Rabi frequency
*Rabi problem
*Vacuum Rabi oscillation
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