News: Research Highlights

Thu January 1, 2009

Observartion of itinerant ferromagnetism in a strongly interacting Fermi gas of ultracold atoms

Ferromagnetism of delocalized (itinerant) fermions occurs due to repulsive interactions and the exchange energy which reduces the interaction energy for spin polarized domains due to the Pauli exclusion principle.  At a critical interaction, given by the so-called Stoner criterion [1], they system spontaneously develops domains and becomes ferromagnetic.  This, together with a suitable band structure...
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Thu January 1, 2009

Buffer-gas Cooled Bose-Einstein Condensate

Now well into its second decade, the experimental realization of Bose-Einstein condensation (BEC) in dilute gases has led to revolutionary advances in physics. Since this achievement the field has moved quickly, with innumerable new developments in coherent atom and molecular optics and nonlinear atom optics, the observation of superfluidity in atomic gases, the study of novel quantum systems, and most recently the study of the BEC-BCS crossover. Despite the breadth of new research, however, the basic recipe for BEC is unchanged from its first realization in alkali atoms: pre-cool a hot sample utilizing laser cooling to permit trapping and provide high densities, followed by evaporative cooling to reach quantum degeneracy.

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Thu January 1, 2009

A quantum gas microscope for detecting single atoms in a Hubbard-regime optical lattice

For the first time it was possible to observe single atoms in an optical lattice, where particles can tunnel from site to site.  An optical lattice is a crystals made of light that can be used to trap atoms at very low temperatures, creating a test bed for fundamental properties of crystalline materials. This research is part of a program on studying novel quantum matter using ultracold quantum gases. The work is led by Markus Greiner, Assistant Professor of Physics, principal investigator at Harvard and member at the NSF funded Harvard-MIT “Center for Ultracold Atoms”.

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Thu January 1, 2009

Demonstration of resolved sideband cavity cooling of a single ion

This is joint work with Vladan Vuletic.
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Thu January 1, 2009

Intense Atomic and Molecular Beams via Neon Buffer gas Cooling

D. Patterson, J. Rasmussen and J.M. Doyle, New Journal of Physics submitted (2009)
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Thu January 1, 2009

TOPS ?09

TOPS, acronym for Teaching Opportunities in the Physical Sciences, is a program to encourage physics majors to pursue careers in pre college science teaching. The 2009 season marked the seventh year that TOPS has been presented. Sponsored by CUA and NSF, TOPS brings eight undergraduate physics majors—juniors and sophomores from across the nation—to MIT for a six week teaching experience. TOPS participants live together as a group in MIT housing, along with a staff assistant from the former year. The participants work with three experienced high school physics teachers to prepare curricular material, design and practice classes, and then they move into the classroom to teach at the middle school and high school levels. The middle school experience takes place in a one-week class on heat, energy and optics at the Museum of Science, Boston.  The material is then revised and presented at the high school level in a two-week class held at MIT in the TOPS teaching workshop. The high school students come from the greater Boston community. The scientific themes of TOPS are seminal to the research program in CUA.  The PIs and graduate students make presentations on research work in progress and arrange laboratory visits, with the goal of enriching the TOPS experience as well and providing some unique teaching resources.  It appears that  about seventy percent of the TOPS participants go on to teaching careers, and in some cases the participants describe the TOPS experience as having been a decisive factor in their career decision. An article on the TOPS program appeared in Physics Today, October, 2009, p.  8.

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Thu January 1, 2009

When one electron is not enough ….

Most research involving ultra-cold matter has been done with atoms with one active electron (i.e. an electron outside a closed shell of electrons).  New theoretical work by CUA researchers has demonstrated that atoms with two active electrons (the so called alkaline-earth atoms)

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Thu January 1, 2009

Coherence and Control of Quantum Registers based on Electronic Spin in a Nuclear Spin Bath

P. Cappellaro, L. Jiang, J. S. Hodges, and M. D. Lukin, Coherence and Control of Quantum Registers based on Electronic Spin in a Nuclear Spin Bath, Phys. Rev. Lett. 102, 210502
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