Atom Optics Research

Atom Optics (computational physics of)

For a list of our atom optics publications see:
Publications by subject and our recent Presentations

Introduction , Our Research , Credits , Bibliography , Atom Chip links

Introduction for non-atomic-physicists

We are researching the fundamental properties of atom optical elements.

Atom Optics is the name given to the physics involving the control and manipulation of atoms. These days, atoms can be routinely cooled using lasers and/or magnetic fields towards temperatures only marginally above absolute zero (approx. -273.15 Degrees Celcius) Eg. MIT's recent record is a cloud of atoms merely 0.000,000,0005 Degrees above absolute zero.

Temperature is related to how fast particles are moving, so cold particles move very slowly. In the ultracold regime (roughly less than one milliKelvin above absolute zero), gas particles enter the world of Quantum Mechanics, where they exhibit wavelike motion. These fields have research will have an amazing impact on society and our technology, and have been bestowed with two sets of Nobel prizes in recent years (1997 for laser cooling of atoms, and 2001 for the creation of the first Bose-Einstein condensates).

One particular direction of current research involves 'atom chips' which use magnetic fields created by microchip wires to trap, cool, and guide atoms above the microchip surface (permanent magnets ala hard disks have also proven useful to create such potentials). Atoms such as Rubidium-87 can be put into 'weak field seeking' states, and are attracted towards the minima of the magnetic potentials:

Magnetic potentials generated by alternating current currying wires on a surface (from Thywissen etal. Eur.Phys.J.D 7 361 (1999))

So... by fabricating wires on microchip surfaces, microtraps can be formed, the ultracold atoms can then be guided through waveguides, and by making patterns with the wires more complicated devices such as beamsplitters have already been demonstrated to be possible. Experimental progress includes the creation and propagation of Bose-Einstein condensates on chip!

Matter wave optics requires all of the analogues of electromagnetic optical elements (eg. lens to focus, beam splitters etc.), and it is also important to produce efficient guides to transport atoms between one component and the next in a confining potential to avoid wave diffraction. The 'atom chip' approach promises significant benefits in terms of being able to fabricate the different atom optical components on the same microchip, using much of the technology that exists for microchip manufacturing.

Samples of our Research

Initial research has been on the (matter) wave mechanics of the simple waveguide bend, which, whilst it is one of the simplest devices required for basic atom optics, yields a surprising array of fundamental Quantum Mechanics at the microscopic scale.

Time-independent approaches were used to examine the transmission and reflection properties of an ideal 3-D circular bend, as well as for matter wave propagation through abrupt changes in the transverse binding potentials.

We then turned to time-dependent Crank-Nicolson calculations. We have used the circular bend to examine the applicability of classical mechanics through Ehrenfest's Theorem to describe wavepacket motion through microstructured waveguides.

We have also demonstrated interference vortices in low-density clouds of atoms simply as a consequence of multimoded wave propagation along a waveguide, with no non-linear effects involved.

Current research directions involve including mean-field (atom-atom) interactions, to examine the effects of the propagation of matter waves with higher densities, and investigating other, more complicated atom optical devices including propagating in ring-geometries.

Credits

Primary Investigator: Dr. Michael Bromley
Current Collaborators: Prof. Brett Esry and Dr. Remigio Cabrera-Trujillo

This research was initiated during 2002-2005 at Kansas State University as part of a ONR-funded project PI'd by Prof. Brett Esry along with Dr. Remigio Cabrera-Trujillo and an undergraduate Ms. Mindy Koehler.

During this time Brett co-organised an ITAMP workshop Quantum Degenerate Gases in Low-Dimensionality October 4-6, 2004.

Bibliography

We compiled an 'atom chip' focussed bibliography. Download the BibTeX file - last update Octoberish 2004 (send any updates to here)

Older 'atom chip' emphasising bibliographies are at ACQUIRE, and the BEC bibliography is available via JILA.

Some Motivators Weblinks (ie. Experimental Chip Groups)

• The EU based ACQUIRE collaboration, has links to most of the European research groups. See also FASTnet.
• Individually: Schmiedmayer, Haensch, Hinds, and Aspect Groups
• Zimmermann Group at Tuebingen
• Center for Ultracold Atoms at MIT (Prentiss group and Group)
• Cornell Group at JILA
• Thywissen Group at Toronto
• Rubinsztein-Dunlop/Vale group at UQ
• Hannaford/Hall group at Swinburne

Some Competitors Weblinks (ie. Theoreticalists in related veins)

• Henkel and Quantum Theory Group at Universitat Potsdam
• Bohn Group at JILA/CU
• Leboeuf / Pavloff at Universite Paris-Sud
• Zozulya Group at Worcester Polytechnic Institute
• Meystre group at University of Arizona
• Bouchoule at Institut d'Optique, Orsay
• Carr group at the University of Mines

Links to pages with many links

• Ultra-Cold-Atom-News
• Atom traps Worldwide
• Quantum Optics
• BEC