Towards quantum simulation with ultracold polar molecules

Lead Research Organisation: Durham University
Department Name: Physics

Abstract

Ultracold and quantum degenerate atomic gases have been exploited to study a vast array of novel and interesting physical phenomena ranging from fundamental studies of superfluidity to strongly-correlated many body systems. As the field has matured there has been a growing interest in the quest to produce similar gases of molecules, where the rich internal structure offers access to new, fascinating physics. One of the most promising routes to these riches is to exploit the ability to cool atomic gases to degeneracy before associating pairs of atoms to form diatomic molecules. In this context the formation of heteronuclear molecules is of particular interest as, in the ground state, the molecules exhibit a permanent electric dipole moment that gives rise to long-range anisotropic interactions. Such interactions dramatically modify the behaviour of the gas at ultracold temperatures and find many applications. One such application is in the area of quantum simulation where a regular array of interacting molecules confined on a three dimensional optical lattice is used to simulate problems more usually associated with condensed matter physics.
The goal of this project is to explore experimental implementations of quantum simulation protocols using ultracold molecules - either RbCs or CsYb. In the case of RbCs, our studies will investigate the use of rotational states of the molecule to encode a pseudo spin for simulation of quantum magnetism, whereas in CsYb experiments can exploit the spin of the unpaired electron. New work will focus on the development of optical lattices in 1D, 2D and 3D. Ultimately we will develop methods to probe the molecules at the level of single lattice sites in order to gain insight into the complex many-body dynamics in the lattice.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509462/1 01/10/2016 30/09/2021
1918074 Studentship EP/N509462/1 01/10/2017 30/09/2021 Jack Segal
 
Description The apparatus of our experiment has been upgraded to allow, for the first time, creation and experimental study of ultracold and quantum degenerate mixtures of Caesium and Ytterbium atoms. Experiments have been performed which have investigated how the physical properties of such a mixture varies compared to an ultracold sample of just one species of atom or the other. We have also implemented atom trapping geometries which limit the dimensions the atoms are free to move in - by careful selection of our trapping parameters, different geometries can be selected for each species of atom. This will allow us to further probe the physical properties of the ultracold mixture.
The creation of ultracold mixtures has also allowed us to investigate the scattering properties and physical interations of the mixture at varying magnetic fields, which in turn will help to identify a suitable process for creating Caesium-Ytterbium molecules, which would be a novel addition to the growing research field of ultracold, dipolar diatomic molecules. The use of a lattice trapping geometry will also assist in making creation of these molecules possible.
Exploitation Route Knowledge of the physical properties of the ultracold mixture will allow the creation and study of new physical systems. In particular, the careful manipulation of the scattering properties and physical interactions of the mixture can create a self-bound cloud of atoms known as a 'quantum droplet'. There is research interest in the physical properties of such droplets, particularly cases such as a Caesium-Ytterbium mixture where the masses of the two components of the mixture are imbalanced.
Access to ultracold samples of Caesium-Ytterbium molecules in the ground state will have a broad range of applications in quantum science, for example, simulation of quantum systems such as various condensed matter systems, quantum information processing, ultracold chemistry and tests of fundamental physics. The Caesium-Ytterbium molecule falls into a smaller subset of diatomic molecules which has both an electric and a magnetic dipole moment in the ground state, which means it can be used to investigate and simulate a wide range of physical systems.
Sectors Aerospace, Defence and Marine,Chemicals,Digital/Communication/Information Technologies (including Software),Energy,Other

 
Description CsYb Droplets - Dilute Quantum Fluids Beyond the Mean-Field
Amount £435,829 (GBP)
Funding ID EP/T01573X/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 12/2019 
End 11/2023
 
Description QSUM: Quantum Science with Ultracold Molecules
Amount £6,731,103 (GBP)
Funding ID EP/P01058X/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 05/2017 
End 05/2022
 
Description Quantum Science with Ultracold Molecules 
Organisation Imperial College London
Department Department of Physics
Country United Kingdom 
Sector Academic/University 
PI Contribution Work towards creation of a new source of ultracold molecule, namely the Caesium-Ytterbium molecule, a molecule with both an electric and magnetic dipole moment, and studying the physical properties of these molecules in optical lattices.
Collaborator Contribution A number of other molecular sources (in the solid state, in traps, and in lattices), controlled coupling of molecules in the solid state to photonic chips, controlled coupling of gas-phase molecules in microtraps to waveguides on a chip. Development of new experiments to observe and study ultracold molecules, namely molecules in optical tweezers, and a quantum gas microscope.
Impact The creation of ultracold mixtures has allowed us to investigate the scattering properties and physical interations of the mixture at varying magnetic fields, which in turn will help to identify a suitable process for creating Caesium-Ytterbium molecules, which would be a novel addition to the growing research field of ultracold, dipolar diatomic molecules. The use of a lattice trapping geometry will also assist in making creation of these molecules possible.
Start Year 2017
 
Description Quantum Science with Ultracold Molecules 
Organisation University of Oxford
Department Department of Physics
Country United Kingdom 
Sector Academic/University 
PI Contribution Work towards creation of a new source of ultracold molecule, namely the Caesium-Ytterbium molecule, a molecule with both an electric and magnetic dipole moment, and studying the physical properties of these molecules in optical lattices.
Collaborator Contribution A number of other molecular sources (in the solid state, in traps, and in lattices), controlled coupling of molecules in the solid state to photonic chips, controlled coupling of gas-phase molecules in microtraps to waveguides on a chip. Development of new experiments to observe and study ultracold molecules, namely molecules in optical tweezers, and a quantum gas microscope.
Impact The creation of ultracold mixtures has allowed us to investigate the scattering properties and physical interations of the mixture at varying magnetic fields, which in turn will help to identify a suitable process for creating Caesium-Ytterbium molecules, which would be a novel addition to the growing research field of ultracold, dipolar diatomic molecules. The use of a lattice trapping geometry will also assist in making creation of these molecules possible.
Start Year 2017