QUANTUM FLUCTUATIONS IN OPTICAL BISTABILITY - CALCULATIONS FROM LINEAR RESPONSE THEORY

We present a new method for computing quantum fluctuations of fields emitted by optical cavities containing atoms. The noise generation by atoms is described by atomic correlation functions. The parametric transformation of the fields by the atomic medium is described by susceptibility functions, as in linear response theory. The susceptibility functions and the correlation functions can be calculated as in the resonance fluorescence theory. The compatibility between dissipation and added fluctuations is ensured by general relations existing between these atomic functions.