Volume 193, Nº 4 (2023)

Jets from young stars are used as an example to review how laboratory modeling enables advancement in understanding the main physical processes responsible for the formation and stability of these amazing objects. The discussion focuses on the options for modeling jet emissions in a laboratory experiment at the PF-3 facility at the National Research Center Kurchatov Institute. Many properties of the flows obtained using this experimental setup are consistent with the main features of jets from young stars.

We discuss the spatial and spectral properties of electromagnetic fields in a squeezed vacuum state and consider photon correlations in such fields. We concentrate on a bright squeezed vacuum with a large mean number of photons per mode and both spatial and frequency multimode structures. A theoretical approach based on the introduction of independent Schmidt modes and their photon operators is considered, which allows analytically correctly describing any characteristics of the squeezed field, including photon correlations, in good agreement with experiment. We present methods for controlling the mode content, degree of squeezing, and entanglement of photons of the generated squeezed light, including the scheme of a nonlinear interferometer; their advantages and applied prospects are analyzed. We discuss applied problems where squeezed nonclassical states are realized: the dispersion characteristics of media in the THz frequency range and high-precision detection of weak phase and angular perturbations based on correlations between photons.