Quantum-degenerate dipolar gases of bialkali molecules

Lead Research Organisation: Durham University
Department Name: Chemistry

Abstract

At very low temperatures, matter enters a new regime where its properties are fully quantum-mechanical. Such quantum matter is very precisely controllable and offers many new properties that are likely to form the basis of future technologies. The EuroQUAM Programme is a EUROCORES Programme coordinated by the European Science Foundation to develop European research in Cold Quantum Matter. This proposal is part of the QuDipMol Collaborative Research Proposal, which brings together five experimental groups (Innsbruck, Freiburg, Firenze/Pisa, Durham and Hannover) and four theory groups (Durham, Orsay, Prague, Innsbruck). QuDipMol aims to form a quantum gas of polar (heteronuclear) alkali metal dimers. The molecules will be formed in traps containing mixed ultracold gases of two different alkali metal atoms, both by photoassociation and magnetic tuning through Feshbach resonances. Methods will be developed to increase the rate of formation and the density of the polar molecules. The Durham experimental group will work to create polar molecules using ultracold atomic gases of rubidium and caesium. This mixture is particularly attractive due to the unique nature of the interatomic collisions for these species, which should provide a means to manipulate the properties of the atomic mixture in order to make the molecule production more favourable.A major problem along the way is that the molecules may be destroyed (or lost from the trap) because of collisions with atoms or other molecules. It is important to understand these collisions, both to work around them during the formation of the molecules and to control the resulting polar quantum gas. The Durham theory group will work to achieve the necessary understanding by developing potential energy surfaces for the systems of interest and carrying out quantum-mechanical reactive scattering calculations.

Publications

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Zuchowski P (2010) Reactions of ultracold alkali-metal dimers in Physical Review A

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Zuchowski PS (2010) Ultracold RbSr molecules can be formed by magnetoassociation. in Physical review letters

 
Description This grant made fundamental advances in the theory of ultracold molecules, at temperatures at or below 1 microkelvin. Major achievements included
- the development of new ways to calculate near-threshold bound states of ultracold molecules (usedin much subsequent research)
- understanding the hyperfine levels of ultracold alkali-metal dimers
- predicting a new mechanicsm for forming ultracold molecules from alkali-metal atoms paired with closed-shell atoms
- understanding which of the possible ultracold alkali-metal dimers will be stable to all possible 2-body collisions
Exploitation Route The work under this grant has been used in many subsequent studies of polar ultracold molecules, including studies of KRb in Boulder, RbCs in Innsbruck and Durham, and work aimed at forming RbSr in Innsbruck (Schreck), LiYb (Washington (Gupta) and Kyoto (Takahashi)) and RbYb (Duesseldorf (Goerlitz)).
Sectors Digital/Communication/Information Technologies (including Software)

 
Description The findings from this grant have underpinned much further work on the production of ultracold molecules from ultracold atoms. The experimental groups in Innsbruck (Naegerl) and Durham (Cornish) have both recently succeeded in producing ultracold polar RbCs molecules in their absolute ground state. Such molecules will be used to explore novel phases of matter and may form the basis of future devices in quantum simulation and quantum information processing. The work done under this proposal underpinned the Programme Grant MMQA: Microkelvin Molecules in a Quantum Array (2010-16) and our follow-on Programme Grant application QSUM: Quantum Science with Ultracold Molecules.
First Year Of Impact 2014
 
Description EPSRC Programme Grant 2010
Amount £6,380,561 (GBP)
Funding ID EP/I012044/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 12/2010 
End 11/2016
 
Description EPSRC Responsive Mode 2010
Amount £1,090,594 (GBP)
Funding ID EP/H003363/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 05/2010 
End 06/2014
 
Description EPSRC Responsive Mode 2015
Amount £994,688 (GBP)
Funding ID EP/N007085/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 12/2015 
End 12/2019
 
Description QuDipMol 
Organisation Albert Ludwig University of Freiburg
Country Germany 
Sector Hospitals 
PI Contribution We developed new theoretical methods to calculate the near-dissociation bound states of ultracold molecules formed from pairs of alkali-metal atoms in magnetic fields. We also investigated the hyperfine structure of the absolute ground states of these molecules, and the outcomes of collisions involving them.
Collaborator Contribution The Freiburg group (Matthias Weidemueller, now in Heidelberg) and the Innsbruck and Durham Physics groups (Hanns-Christoph Naegerl and Simon Cornish, respectively) carried out experiments to produce ultracold molecules from ultracold atoms. The Orsay group worked on potential energy curves and the theory of electronically excited states.
Impact During the grant, most of the outcomes were important enough that the partners published their results separately. One major exception was a paper in Nature Physics in 2010 on Cs2 molecule formation, which now (2014) has over 140 citations, The collaboration with Innsbruck and Durham Physics has now (2014) succeeded in producing ultracold polar RbCs molecules in their absolute ground states.
Start Year 2007
 
Description QuDipMol 
Organisation Durham University
Country United Kingdom 
Sector Academic/University 
PI Contribution We developed new theoretical methods to calculate the near-dissociation bound states of ultracold molecules formed from pairs of alkali-metal atoms in magnetic fields. We also investigated the hyperfine structure of the absolute ground states of these molecules, and the outcomes of collisions involving them.
Collaborator Contribution The Freiburg group (Matthias Weidemueller, now in Heidelberg) and the Innsbruck and Durham Physics groups (Hanns-Christoph Naegerl and Simon Cornish, respectively) carried out experiments to produce ultracold molecules from ultracold atoms. The Orsay group worked on potential energy curves and the theory of electronically excited states.
Impact During the grant, most of the outcomes were important enough that the partners published their results separately. One major exception was a paper in Nature Physics in 2010 on Cs2 molecule formation, which now (2014) has over 140 citations, The collaboration with Innsbruck and Durham Physics has now (2014) succeeded in producing ultracold polar RbCs molecules in their absolute ground states.
Start Year 2007
 
Description QuDipMol 
Organisation University Paris Sud
Country France 
Sector Academic/University 
PI Contribution We developed new theoretical methods to calculate the near-dissociation bound states of ultracold molecules formed from pairs of alkali-metal atoms in magnetic fields. We also investigated the hyperfine structure of the absolute ground states of these molecules, and the outcomes of collisions involving them.
Collaborator Contribution The Freiburg group (Matthias Weidemueller, now in Heidelberg) and the Innsbruck and Durham Physics groups (Hanns-Christoph Naegerl and Simon Cornish, respectively) carried out experiments to produce ultracold molecules from ultracold atoms. The Orsay group worked on potential energy curves and the theory of electronically excited states.
Impact During the grant, most of the outcomes were important enough that the partners published their results separately. One major exception was a paper in Nature Physics in 2010 on Cs2 molecule formation, which now (2014) has over 140 citations, The collaboration with Innsbruck and Durham Physics has now (2014) succeeded in producing ultracold polar RbCs molecules in their absolute ground states.
Start Year 2007
 
Description QuDipMol 
Organisation University of Innsbruck
Country Austria 
Sector Academic/University 
PI Contribution We developed new theoretical methods to calculate the near-dissociation bound states of ultracold molecules formed from pairs of alkali-metal atoms in magnetic fields. We also investigated the hyperfine structure of the absolute ground states of these molecules, and the outcomes of collisions involving them.
Collaborator Contribution The Freiburg group (Matthias Weidemueller, now in Heidelberg) and the Innsbruck and Durham Physics groups (Hanns-Christoph Naegerl and Simon Cornish, respectively) carried out experiments to produce ultracold molecules from ultracold atoms. The Orsay group worked on potential energy curves and the theory of electronically excited states.
Impact During the grant, most of the outcomes were important enough that the partners published their results separately. One major exception was a paper in Nature Physics in 2010 on Cs2 molecule formation, which now (2014) has over 140 citations, The collaboration with Innsbruck and Durham Physics has now (2014) succeeded in producing ultracold polar RbCs molecules in their absolute ground states.
Start Year 2007