Browse Physics

A new method for computing electron properties in many-electron molecules yields better results at lower computational cost.

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.

Lasers can make an opaque material transparent, but to determine how long this state survives, you have to shut off the lights.

Researchers created an ultracold plasma with molecules, rather than atoms, which opens a new window into the dynamics of this strange state of matter.

Successive and rapid measurements of a quantum system can prevent it from evolving in time. This quantum Zeno effect has now been demonstrated for light inside a cavity.

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.

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.

Tuning the interactions between ultracold atoms leads to a strongly interacting superfluid with properties more akin to liquid helium than a dilute Bose-Einstein condensate.

Atoms subjected to strong optical fields exhibit splitting of energy levels. The same effect has now been observed when an atom moves through the periodic field of a crystal lattice.

When an atom is bombarded with just enough energy to fully ionize it, how do the electrons and nucleus break apart from each other? Experimentalists are now able to study such a four-body breakup by bombarding a helium atom with an electron.

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.

The atoms in highly excited vibrational states of a diatomic molecule can be quite far apart near their maximum excursion. Physicists are now using laser spectroscopy to carefully measure the long-range effective interaction between potassium atoms in these states—an essential parameter to understanding ultracold atomic collisions.

Lasers can confine atoms in one-dimensional traps. Now, the right superposition of lasers can act as one-way barriers that let atoms move in one direction, but not the other.

In the 1970s and 80s, researchers developed techniques for cooling atoms to very low temperatures using laser light. The work led to improvements in atomic clocks and the observation of a new ultracold state of matter.

Researchers demonstrated an atom slowing and trapping scheme that may apply to elements that have been difficult or impossible to cool before. The atoms need only an unpaired electron, not a special set of internal states.

Researchers have extracted electrons from atoms in a controlled way using sub-femtosecond light pulses. They also imaged the electrons’ quantum states with unprecedented clarity.

Particles floating in a fluid don’t simply ‘go with the flow’ but cut across the fluid currents, according to experiments that measured both the particles and the fluid independently.

Researchers cooled large dye molecules to one-tenth of a degree Kelvin–the coldest temperature ever for large molecules. The technique could work with protein molecules and allow a new level of precision spectroscopy.