K. Rzazewski et al., Statistics of atomic populations in output coupled wave packets from Bose-Einstein condensates: Four-wave mixing - art. no. 013606, PHYS REV A, 6001(1), 2000, pp. 3606
The statistics of the atomic population distributions in nonlinear matter-w
ave processes, such as four-wave mixing of matter waves (or output coupled
wave packets produced by Bragg scattering) from Bose-Einstein condensates (
BECs), an determined. Fluctuations of the populations of atoms in the four-
wave mixing wave packet can be due to (a) fluctuations of the laser fields
that produce the separate momentum wave packets of the BEG, (b) quantum flu
ctuations arising from finite temperature effects, and (c) the quantum-mech
anical nature of the mean-field BEC wave function. We focus on the latter s
ource of fluctuations. The distribution of the number of atoms in the four-
wave mixing wave packet is binomial and reduces to a Gaussian distribution
for strong conversion. We calculate the skewness and kurtosis of the distri
bution. The differences in the nature of the fluctuations in nonlinear phen
omena for atoms (matter waves) and photons are discussed.