In recent years, physicists have been using lasers to cool atoms to temperatures hovering near absolute zero. As temperatures drop, atomic movement slows dramatically – something that allowed these scientists to observe the behavior and structure of individual atoms with more precision than ever before.
These newly creatable conditions have offered the ability to finally study phenomena predicted decades ago.
Prof. Lev Khaykovich of the Department of Physics at Bar Ilan University uses laser-based techniques to slow down atoms’ movements, lower their temperatures, and manipulate their behavior in a Bose-Einstein Condensate (BEC).
As the atoms in the BEC act as if they are an individual, the laboratory team is able to model the atomic-level behavior of complex systems.
These studies are helping to characterize the quantum behavior of atoms – something that may improve scientists’ ability to measure and understand fundamental forces such as electromagnetism and gravity.
Khaykovich and his research team pursue a number of research topics:
Few-body physics is universal when inter-particle interactions are insensitive to the microscopic details of the short-range interaction potentials and can be characterized by only one or few universal parameters.
In this regime, peculiar quantum mechanical states were predicted in the 1970s in the framework of nuclear physics. However, only the platform of ultracold atoms allowed their experimental research in recent years.
Khaykovich’s lab also studies matter-wave solitons. A trapped atomic BEC, with attractive interactions, is stable if the number of atoms in it is below a critical value. Above this critical value collapse occurs, causing the atoms to act as individuals.
Beneath the collapse threshold, the BEC can form stable wave packets in a one-dimensional (1D) trap, which is tightly confined in two (transverse) directions and is unbound along the longitudinal axis. In that case, the stability of bright solitons is provided by balance among the quantum pressure, alias matter-wave dispersion and mean-field attraction.
Under external feedback, laser oscillations turn chaotic. Khaykovich’s team investigates new regimes of chaos and polarization dynamics in semiconductor lasers subject to this type of feedback. In their studies they have encountered several interesting properties of such lasers that can be useful in industrial applications and optical communications.