Synopsis: Cooling Neutral Atoms in Optical Tweezers

Individual neutral atoms trapped in optical tweezers have been cooled to their quantum ground state, raising hopes that they can be used to process quantum information.
Synopsis figure
A. Kaufmann et al., Phys. Rev. X (2012)

To probe the quantum-mechanical world, and perhaps someday to exploit it for ultrapowerful computing, experimenters must isolate and control individual quantum systems. Isolated ions are easy to trap, but another promising candidate is a single neutral atom, which is less sensitive to nearby stray electric fields. In work reported in Physical Review X, Adam Kaufman and co-workers at JILA and the University of Colorado, both in Boulder, demonstrated that an atom held by a tightly focused laser beam known as optical tweezers can be effectively laser cooled into its quantum ground state, where its quantum nature is most clearly exposed and manipulated.

The insensitivity of a neutral atom to external fields unfortunately makes it hard to confine it tightly in the type of electromagnetic trap that is used for ions. Such tight confinement creates large energy separations between different vibrational modes of an ion, making it relatively easy to cool its motions into the lowest-energy state. In an established scheme known as Raman-sideband cooling, for example, one pair of lasers is tuned so that it is absorbed mostly by ions that are vibrationally excited, and then another laser returns them to a less-excited state. Kaufman and his colleagues showed that properly configured optical tweezers can hold a neutral atom tightly enough to be cooled in the same way, so that a trapped rubidium atom was placed in its ground state with a 90% probability. In the future, tweezers could move a trapped atom around to allow controlled quantum interactions with other atoms or with an external circuit. – Don Monroe


More Features »


More Announcements »

Subject Areas

Atomic and Molecular PhysicsQuantum Information

Previous Synopsis

Atomic and Molecular Physics

Laser Suppression of Noise

Read More »

Related Articles

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: Linking Two Quantum Dots with Single Photons

Viewpoint: Linking Two Quantum Dots with Single Photons

Researchers have transferred quantum information from one quantum dot to another dot 5 m away using photonic qubits as the relay. 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