Rydberg crystals and supersolids

Lead Research Organisation: Durham University
Department Name: Physics

Abstract

High-temperature superconductors are a technologically important example of a strongly correlated quantum system. They owe their exotic electronic properties to interactions between the electrons, which give rise to correlated behaviour.

Strongly correlated materials are very difficult to model they lie in between - the electrons interact, and so can't be described as individual particles, but the strong interactions also mean that we can't use a ``bulk'' description based on average properties either.

To bridge the gap between simple models and real materials, there is growing interest in simulating strongly correlated behaviour using laser cooled atoms, where the external and internal state of each atom can be completely controlled. Recently it has become possible to extend this control to the interactions, by exciting the outermost electron to a highly excited (or Rydberg state) using a laser pulse. This switches on a dipole-dipole interaction which is 12 orders of magnitude stronger than that between the ground state atoms. The interactions completely dominate the kinetic energy of the cold (5 microKelvin) atoms, and the system becomes strongly correlated.

In this proposal, we will exploit the unique properties of strontium Rydberg atoms to explore how these strong interactions lead to spatial correlations. In particular we will examine the interplay between these correlations and superfluidity.

The first challenge is to develop a technique for imaging the Rydberg atoms. To do this, we will develop a new kind of scanning microscopy that exploits the fact that strontium atoms have two valence electrons.
Next, we will use this new technique to observe how the interactions lead to the dynamical formation of ``Rydberg crystals'' where the Rydberg excitations form an ordered lattice.
Then, to combine these strong interactions with superfluidity, we will use a weak coupling to the Rydberg state to ``dress'' atoms in their ground state with a small amount of Rydberg character. By combining this ``Rydberg dressing'' with a Bose-Einstein condensate, we will be able to controllably introduce spatial correlations into a superfluid, providing a new laboratory for studying the physics of strongly correlated systems. Recent theoretical proposals have suggested that this could lead to the observation of a ``Rydberg supersolid'', where a crystalline spatial distribution can coexist with superfluid flow - similar to a phase predicted to exist in solid helium over 40 years ago.

Planned Impact

In the immediate term, the UK economy will benefit from the supply of highly trained personnel. Two PG students and one PDRA will receive high quality scientific training and training in transferable skills. The skills they will acquire could be applied in the academic, defence and R&D sectors and beyond. This proposal will also drive the development of high-tech equipment, with the potential to benefit UK SMEs in e.g. photonics.

Local schools will benefit from targeted outreach activities undertaken during the proposal. We will develop our web pages and links to social networks to maximise the wider societal and cultural impact.

In the long term, significant economic benefit would arise from an improved understanding of strongly correlated materials, some of which (such as high-Tc superconductors) already have important technological applications. Researchers in this area, in both the condensed matter and atomic physics communities, benefit strongly from this proposal, which provides a new approach to studying strong correlations in a clean environment.

Economic benefits could also arise by applying the techniques developed here to the creation of large-scale entangled sates, with applications in precision measurement.

Publications

10 25 50
publication icon
Bounds AD (2018) Rydberg-Dressed Magneto-optical Trap. in Physical review letters

publication icon
Bowden W (2017) Rydberg electrometry for optical lattice clocks in Physical Review A

publication icon
Gil LI (2014) Spin squeezing in a Rydberg lattice clock. in Physical review letters

publication icon
Hanley R (2017) Probing interactions of thermal Sr Rydberg atoms using simultaneous optical and ion detection in Journal of Physics B: Atomic, Molecular and Optical Physics

publication icon
Kliese R (2016) Difference-frequency combs in cold atom physics in The European Physical Journal Special Topics

publication icon
Sadler D (2017) Radiation trapping in a dense cold Rydberg gas in Physical Review A

publication icon
Vaillant C (2014) Multichannel quantum defect theory of strontium bound Rydberg states in Journal of Physics B: Atomic, Molecular and Optical Physics

 
Description They key findings fall into three categories:

1. Our research concerns the use of lasers to excite atoms to very highly excited states (known as Rydberg states) that exist near the ionization threshold. In this project, we discovered that an additional excitation mechanism occurs in dense clouds. Laser photons can bounce around within the cloud, becoming trapped. These trapped photons can also create Rydberg states, but with different properties.

2. We developed a new type of high power, tunable laser system in the tradionally hard to reach ultraviolet region of the spectrum. This has enabled us to excite Rydberg atoms with very high spectroscopic resolution. Using a device called an optical frequency comb, we can directly reference these measurements to the SI second, improving the precision of these measurements by 3 orders of magnitude.

3. Using this laser, we can admix a small amount of the Rydberg state into atoms that are also being cooled by laser light. This si the first time that such highly excited atoms have been laser cooled, and is a breakthrough in the field.
Exploitation Route Other researchers in the field of quantum simulation can use our finding to help design better experiments.
Sectors Education,Other

URL https://www.jqc.org.uk/research/two-electron-rydberg-systems/
 
Description Our reserach has been used to: 1. Initiate a new collaboration on femtosecond combs with a company (Toptica Photonics AG) 2. Help researchers at the National Physical laboratory better understand systematic errors due to electric fields in their atomic clocks.
First Year Of Impact 2012
Sector Education,Other
Impact Types Cultural,Societal

 
Description FP7-ICT
Amount £263,729 (GBP)
Funding ID 612862 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 02/2014 
End 02/2017
 
Description EU H2020 project RYSQ 
Organisation Aarhus University
Country Denmark 
Sector Academic/University 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation Center of Medical Research Lambaréné
Country Gabon 
Sector Charity/Non Profit 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation ETH Zurich
Country Switzerland 
Sector Academic/University 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation Eindhoven University of Technology
Country Netherlands 
Sector Academic/University 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation Heidelberg University
Country Germany 
Sector Academic/University 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation Max Planck Society
Country Germany 
Sector Charity/Non Profit 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation National Center for Scientific Research (Centre National de la Recherche Scientifique CNRS)
Country France 
Sector Public 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation National Research Council
Country Italy 
Sector Public 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation University of Amsterdam
Country Netherlands 
Sector Academic/University 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation University of Innsbruck
Country Austria 
Sector Academic/University 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation University of Kassel
Country Germany 
Sector Academic/University 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation University of Nottingham
Country United Kingdom 
Sector Academic/University 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation University of Stuttgart
Country Germany 
Sector Academic/University 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description EU H2020 project RYSQ 
Organisation University of Ulm
Country Germany 
Sector Academic/University 
PI Contribution Workpackage leader on New Platforms for Quantum Simulation
Collaborator Contribution Research and administration
Impact Publications https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-3-2281
Start Year 2015
 
Description HAIRS project EU funded STREP 
Organisation Eberhard Karls University of Tubingen
Country Germany 
Sector Academic/University 
PI Contribution PI of Durham node in 3 year funded EU STREP proposal (note amount of funding lusted under "further funding". Durham contributes a state--of-the-art laser cooling/Rydberg experiment to this project that aims to couple Rydbergs and semiconductors
Collaborator Contribution Other experimental and theoretical expertise
Impact PUBLICATIONS 1. http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.103601 2. http://iopscience.iop.org/0953-4075/47/15/155001/ 3. http://iopscience.iop.org/0953-4075/47/19/199601/
Start Year 2014
 
Description HAIRS project EU funded STREP 
Organisation L'Institut d'Optique Graduate School
Country France 
Sector Academic/University 
PI Contribution PI of Durham node in 3 year funded EU STREP proposal (note amount of funding lusted under "further funding". Durham contributes a state--of-the-art laser cooling/Rydberg experiment to this project that aims to couple Rydbergs and semiconductors
Collaborator Contribution Other experimental and theoretical expertise
Impact PUBLICATIONS 1. http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.103601 2. http://iopscience.iop.org/0953-4075/47/15/155001/ 3. http://iopscience.iop.org/0953-4075/47/19/199601/
Start Year 2014
 
Description HAIRS project EU funded STREP 
Organisation Max Planck Society
Department Max Planck Institute for the Physics of Complex Systems
Country Germany 
Sector Charity/Non Profit 
PI Contribution PI of Durham node in 3 year funded EU STREP proposal (note amount of funding lusted under "further funding". Durham contributes a state--of-the-art laser cooling/Rydberg experiment to this project that aims to couple Rydbergs and semiconductors
Collaborator Contribution Other experimental and theoretical expertise
Impact PUBLICATIONS 1. http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.103601 2. http://iopscience.iop.org/0953-4075/47/15/155001/ 3. http://iopscience.iop.org/0953-4075/47/19/199601/
Start Year 2014
 
Description HAIRS project EU funded STREP 
Organisation University of Nottingham
Country United Kingdom 
Sector Academic/University 
PI Contribution PI of Durham node in 3 year funded EU STREP proposal (note amount of funding lusted under "further funding". Durham contributes a state--of-the-art laser cooling/Rydberg experiment to this project that aims to couple Rydbergs and semiconductors
Collaborator Contribution Other experimental and theoretical expertise
Impact PUBLICATIONS 1. http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.103601 2. http://iopscience.iop.org/0953-4075/47/15/155001/ 3. http://iopscience.iop.org/0953-4075/47/19/199601/
Start Year 2014