In a cooled and trapped cloud of ytterbium atoms, the transition from a superfluid to an insulating state has been observed, opening up new possibilities for precision measurements, optical clocks, and quantum computing.
Inelastic light scattering is used to study correlated phases of one-dimensional Bose gases. This spectroscopic technique can distinguish superfluid and insulating phases and allow identification of the transition from one to the other.
Trapped cold atom gases mimic much of the behavior of electrons in a solid, but because the atoms are neutral, it is difficult to imitate the physics of electrons moving in a magnetic field. Now, experiments show that a suitable combination of lasers can create an artificial magnetic field for cold atoms.
Stochastic resonance, in which a periodic signal applied to a nonlinear system can be amplified by adding noise, has been observed in a mechanical system and predicted to occur in a Bose-Einstein condensate.
Disorder in a crystal tends to localize electrons and drive a transition from a metallic to an insulating state. The same localization can occur in cold atom gasses in a periodic optical trap, but since the trap is tunable it may be possible to explore this effect in multiple dimensions.
Spin dependence of atomic and electronic interactions can give rise to propagating regions of aligned spins in solids called spin waves. These have now been observed in a gas of ultracold fermionic atoms.
Paramagnetic atoms and molecules experience a force in a magnetic field and scientists have now used this force to decelerate and trap hydrogen atoms. This method promises new opportunities for precision measurements on hydrogen isotopes and may be applied to a host of atoms and molecules for which existing cooling techniques fail.
Physics1, 24 (2008) – Published September 25, 2008
Atoms colliding in a magnetic field can form weakly bound states called Feshbach molecules. These states have now been used in combination with advanced laser techniques to create tightly bound ground-state molecules close to quantum degeneracy.
A Bose-Einstein condensate (BEC) can dramatically collapse and explode when the interactions between the atoms are sufficiently strong and attractive. Now, scientists have imaged the anisotropic, clover-leaf shape of such a collapsing gas when the attractive atomic interactions are strongly dipolar.
Results from string theory, generalizing the anti-de Sitter/conformal field theory correspondence, may offer a fresh set of mathematical tools for understanding some kinds of phase transitions that occur in cold atomic systems.