Synopsis: Hubbard model for ultracold atoms

A well-known model in condensed matter physics has now been applied to ultracold atoms in an optical lattice.
Synopsis figure
Illustration: NIST

Ultracold atoms stored in optical lattices are a highly controllable way to study systems of strongly correlated particles, offering the possibility of better understanding key phenomena in condensed matter physics. On the condensed matter side, a key tool in every researcher’s kit is the Hubbard model, which was developed in the 1960s to investigate the insulating and conducting states of electrons in solids. This model consists of particles on a lattice, in which the Hamiltonian combines an on-site energy and a “hopping” term to account for tunneling from site to site. Now, in a paper in Physical Review Letters, Hans Peter Büchler of the University of Stuttgart, Germany, reports an analysis of the Hubbard model for two ultracold atoms moving through an optical lattice trap.

In Büchler’s work, the two particles interact through a Feshbach resonance that allows the interaction to be tuned all the way from attraction to strong repulsion. For atoms in a three-dimensional lattice, the author is able to exactly calculate the bound-state energies and band structure and compare with predictions of the Hubbard model. As the interaction strength increases, however, the Hubbard picture deviates more and more from the exact solution, a finding that will be important as experimental efforts seek to observe ordered magnetic and superconducting phases in the strongly interacting regime. – David Voss


Features

More Features »

Announcements

More Announcements »

Subject Areas

Atomic and Molecular PhysicsOptics

Previous Synopsis

Next Synopsis

Related Articles

Focus: 3D Images 10 Times Faster
Interdisciplinary Physics

Focus: 3D Images 10 Times Faster

3D x-ray phase-contrast images take as little as one-tenth the usual time to acquire using a technique that halves the number of required “photos.” Read More »

Synopsis: Beam Splitter is Printed On-Demand
Industrial Physics

Synopsis: Beam Splitter is Printed On-Demand

3D printing enables researchers to quickly fabricate a complex part for a molecular beam experiment. Read More »

Viewpoint: A Diatomic Molecule is One Atom too Few
Atomic and Molecular Physics

Viewpoint: A Diatomic Molecule is One Atom too Few

The successful laser cooling of a triatomic molecule paves the way towards the study of ultracold polyatomic molecules. Read More »

More Articles