John C. Englund

Macroscopic manifestations of quantum noise

Abstract Macroscopic manifestations of quantum noise are discussed in relation to nonlinear quantum systems which cause amplification of fluctuations that stem from quantum spontaneous initiation. Such processes have been analyzed theoretically and experimentally in superfluorescence, theoretically in swept-gain superflourescence, and recently analyzed theoretically in spontaneously generated Raman scattering. Realization of amplified quantum fluctuations in terms of spontaneously generated soliton formation in the electromagnetic field propagation in stimulated Raman scattering is discussed and interpreted in connection with these cases.

Conditions For The Spontaneous Generation Of Solitons In Stimulated Raman Scattering

Quantum phase fluctuations may be amplified into large, sudden phase shifts in the Stokes field, which subsequently give rise to solitons in the pump intensity. Ensemble simulations indicate that increased dissipation due to collisional dephasing within the medium significantly increases the frequency of soliton generation. The statistical distribution of soliton heights and positions is described.

Bistability, Hysteresis, And Transitions To Chaos In A Model Of Coherent, Unimolecular Excitation

A model describing the dynamics of an irradiated SF6 molecule was previously shown to yield chaotic trajectories. We have found that neutrally stable oscillatory states are also possible within windows of the parameter space. When dissipation is added to the model, we have found bistability, both between fixed points and limit cycles, and between limit cycles and other limit cycles. By dynamically varying the laser detuning, we have proven that hysteresis cycles result.