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Details of Grant 

EPSRC Reference: EP/D504821/1
Title: Cold Dipolar Gases
Principal Investigator: Tarbutt, Professor MR
Other Investigators:
Hinds, Professor EA
Researcher Co-Investigators:
Project Partners:
Department: Physics
Organisation: Imperial College London
Scheme: Standard Research (Pre-FEC)
Starts: 01 October 2005 Ends: 31 March 2009 Value (£): 279,276
EPSRC Research Topic Classifications:
Quantum Fluids & Solids
EPSRC Industrial Sector Classifications:
No relevance to Underpinning Sectors
Related Grants:
Panel History:  
Summary on Grant Application Form
Over the last 20 years, researchers have learnt how to cool atoms to extremely low temperatures. Temperatures less than one billionth of a degree above absolute zero have been achieved. At these temperatures, the atoms behave in a completely different way, and the study of their behaviour has occupied physicists for many years. In many ways, ultracold molecules are even more fascinating than ultracold atoms, because a molecule typically has a positive and a negative end. The molecules can interact rather strongly with one another, the positive end of one repelling the positive end of its neighbour for example. When the molecules are cold enough they will form certain kinds of ordered structures. They can order themselves into a crystal-like structure for example, or they can be made to mimic the extraordinary phenomena of superfluidity and of superconductivity.Unfortunately, the cooling techniques that work so well for atoms do not work for molecules. Instead of getting colder, the molecules just start to vibrate. In this project we plan to cool molecules by using ultracold atoms as a refrigerator. We will overlap some molecules with some ultracold atoms and allow the two species to reach thermal equilibrium.Before we can do this we will have to bring the molecules to rest so that they can't fly out of the refrigerator. We can use the fact that the molecules have a positive end and a negative end to slow them down and bring them to rest. Suppose our molecule lies in the region between two plates, one charged to a positive voltage, and the other charged negatively. The molecule orients itself with its positive end closer to the negative plate and its negative end closer to the positive plate. The positive end of the molecule is pulled towards the negative plate, and the negative end is pulled towards the positive plate. If the electric field is uniform the two opposing forces are exactly equal and the molecule cannot move in either direction. If, on the other hand, the electric field is not uniform, the two forces are not equal and the molecule will begin to move. If the positive plate pulls harder for example, the molecule will move towards it. By using such non-uniform electric fields, we will bring fast-moving molecules to rest. We will then confine these molecules to a small region of space and introduce the ultracold atoms which act as the refrigerant.Another idea that we plan to try is to make the ultracold atoms themselves behave like molecules. We will do this by applying an extremely large electric field to the atoms. In this electric field, the electrons are pulled one way while the nuclei are pulled the other way. If the forces are strong enough, the atom effectively obtains a positive and a negative end and so starts to look and behave like a molecule.
Key Findings
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Organisation Website: http://www.imperial.ac.uk