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Doublon dynamics and polar molecule production in an optical lattice.

Covey JP, Moses SA, Gärttner M, Safavi-Naini A, Miecnikowski MT, Fu Z, Schachenmayer J, Julienne PS, Rey AM, Jin DS, Ye J - Nat Commun (2016)

Bottom Line: Here we use such a system to prepare a density distribution where lattice sites are either empty or occupied by a doublon composed of an interacting Bose-Fermi pair.Additionally, we can probe the distribution of the atomic gases in the lattice by measuring the inelastic loss of doublons.These techniques realize tools that are generically applicable to studying the complex dynamics of atomic mixtures in optical lattices.

View Article: PubMed Central - PubMed

Affiliation: JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, USA.

ABSTRACT
Polar molecules in an optical lattice provide a versatile platform to study quantum many-body dynamics. Here we use such a system to prepare a density distribution where lattice sites are either empty or occupied by a doublon composed of an interacting Bose-Fermi pair. By letting this out-of-equilibrium system evolve from a well-defined, but disordered, initial condition, we observe clear effects on pairing that arise from inter-species interactions, a higher partial-wave Feshbach resonance and excited Bloch-band population. These observations facilitate a detailed understanding of molecule formation in the lattice. Moreover, the interplay of tunnelling and interaction of fermions and bosons provides a controllable platform to study Bose-Fermi Hubbard dynamics. Additionally, we can probe the distribution of the atomic gases in the lattice by measuring the inelastic loss of doublons. These techniques realize tools that are generically applicable to studying the complex dynamics of atomic mixtures in optical lattices.

No MeSH data available.


Related in: MedlinePlus

A schematic of the experiment.Starting with a mixture of K, Rb and doublons (the smaller blue ball, the larger red ball and the pair grouped with grey background, respectively) in a 3D lattice, we sweep the magnetic field from above the s-wave Feshbach resonance (at ) to below the resonance to create Feshbach molecules. These molecules are then transferred to their ro-vibrational ground state via STIRAP (stimulated Raman adiabatic passage). After unpaired atoms are removed with resonant light, the STIRAP process is reversed to transfer the ground-state molecules back to Feshbach molecules. The field is then swept above  to dissociate the molecules and create doublons. After holding for a time, , at Bhold, we measure the conversion efficiency when sweeping the field below  to re-form Feshbach molecules. To detect molecules, we use a rf pulse to spin flip the unpaired K atoms to a dark state (ball with black dashed edge) before dissociating the Feshbach molecules and imaging K atoms. The bottom panel illustrates possible dynamics of the doublons during Bhold. As shown schematically, lattice sites populated with a K and a Rb atom have an interaction energy shift . The K tunnelling energies in the lowest and first excited bands are denoted by  and , respectively. Rb tunnelling happens at a slower rate since it experiences a deeper lattice.
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f1: A schematic of the experiment.Starting with a mixture of K, Rb and doublons (the smaller blue ball, the larger red ball and the pair grouped with grey background, respectively) in a 3D lattice, we sweep the magnetic field from above the s-wave Feshbach resonance (at ) to below the resonance to create Feshbach molecules. These molecules are then transferred to their ro-vibrational ground state via STIRAP (stimulated Raman adiabatic passage). After unpaired atoms are removed with resonant light, the STIRAP process is reversed to transfer the ground-state molecules back to Feshbach molecules. The field is then swept above to dissociate the molecules and create doublons. After holding for a time, , at Bhold, we measure the conversion efficiency when sweeping the field below to re-form Feshbach molecules. To detect molecules, we use a rf pulse to spin flip the unpaired K atoms to a dark state (ball with black dashed edge) before dissociating the Feshbach molecules and imaging K atoms. The bottom panel illustrates possible dynamics of the doublons during Bhold. As shown schematically, lattice sites populated with a K and a Rb atom have an interaction energy shift . The K tunnelling energies in the lowest and first excited bands are denoted by and , respectively. Rb tunnelling happens at a slower rate since it experiences a deeper lattice.

Mentions: The experiment proceeds in steps as depicted schematically in Fig. 1. To prepare the doublons, we create a sample of molecules in their ro-vibrational ground state in the lattice as described in ref. 11 and then remove unpaired atoms with resonant light, so that all lattice sites are either empty or contain a single molecule. We then transfer the ground-state molecules back to a weakly bound Feshbach molecule state, followed by a magnetic-field (B) sweep to above the resonance to create a clean system of doublons. The solid black line in the upper panel of Fig. 1 shows schematically B relative to the s-wave Feshbach resonance (dashed line) that is used to manipulate the atomic inter-species interactions and to create molecules. After this preparation, the doublons are left to evolve in the lattice for a variable time . Our measurement then consists of sweeping B to below the resonance to associate atoms into Feshbach molecules and determining the fraction of K atoms that form molecules. Specifically, we measure the molecule number using the following protocol. We first apply radio frequency (rf) to spin-flip the unpaired K atoms to another hyperfine state, which renders the unpaired K atoms invisible for subsequent molecular detection. We then sweep B back above the resonance to dissociate the molecules, and measure the number of resulting K atoms by spin-selective resonant absorption imaging. The conversion efficiency is determined by dividing this molecule number by the total number of K atoms measured when we do not apply the rf.


Doublon dynamics and polar molecule production in an optical lattice.

Covey JP, Moses SA, Gärttner M, Safavi-Naini A, Miecnikowski MT, Fu Z, Schachenmayer J, Julienne PS, Rey AM, Jin DS, Ye J - Nat Commun (2016)

A schematic of the experiment.Starting with a mixture of K, Rb and doublons (the smaller blue ball, the larger red ball and the pair grouped with grey background, respectively) in a 3D lattice, we sweep the magnetic field from above the s-wave Feshbach resonance (at ) to below the resonance to create Feshbach molecules. These molecules are then transferred to their ro-vibrational ground state via STIRAP (stimulated Raman adiabatic passage). After unpaired atoms are removed with resonant light, the STIRAP process is reversed to transfer the ground-state molecules back to Feshbach molecules. The field is then swept above  to dissociate the molecules and create doublons. After holding for a time, , at Bhold, we measure the conversion efficiency when sweeping the field below  to re-form Feshbach molecules. To detect molecules, we use a rf pulse to spin flip the unpaired K atoms to a dark state (ball with black dashed edge) before dissociating the Feshbach molecules and imaging K atoms. The bottom panel illustrates possible dynamics of the doublons during Bhold. As shown schematically, lattice sites populated with a K and a Rb atom have an interaction energy shift . The K tunnelling energies in the lowest and first excited bands are denoted by  and , respectively. Rb tunnelling happens at a slower rate since it experiences a deeper lattice.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834636&req=5

f1: A schematic of the experiment.Starting with a mixture of K, Rb and doublons (the smaller blue ball, the larger red ball and the pair grouped with grey background, respectively) in a 3D lattice, we sweep the magnetic field from above the s-wave Feshbach resonance (at ) to below the resonance to create Feshbach molecules. These molecules are then transferred to their ro-vibrational ground state via STIRAP (stimulated Raman adiabatic passage). After unpaired atoms are removed with resonant light, the STIRAP process is reversed to transfer the ground-state molecules back to Feshbach molecules. The field is then swept above to dissociate the molecules and create doublons. After holding for a time, , at Bhold, we measure the conversion efficiency when sweeping the field below to re-form Feshbach molecules. To detect molecules, we use a rf pulse to spin flip the unpaired K atoms to a dark state (ball with black dashed edge) before dissociating the Feshbach molecules and imaging K atoms. The bottom panel illustrates possible dynamics of the doublons during Bhold. As shown schematically, lattice sites populated with a K and a Rb atom have an interaction energy shift . The K tunnelling energies in the lowest and first excited bands are denoted by and , respectively. Rb tunnelling happens at a slower rate since it experiences a deeper lattice.
Mentions: The experiment proceeds in steps as depicted schematically in Fig. 1. To prepare the doublons, we create a sample of molecules in their ro-vibrational ground state in the lattice as described in ref. 11 and then remove unpaired atoms with resonant light, so that all lattice sites are either empty or contain a single molecule. We then transfer the ground-state molecules back to a weakly bound Feshbach molecule state, followed by a magnetic-field (B) sweep to above the resonance to create a clean system of doublons. The solid black line in the upper panel of Fig. 1 shows schematically B relative to the s-wave Feshbach resonance (dashed line) that is used to manipulate the atomic inter-species interactions and to create molecules. After this preparation, the doublons are left to evolve in the lattice for a variable time . Our measurement then consists of sweeping B to below the resonance to associate atoms into Feshbach molecules and determining the fraction of K atoms that form molecules. Specifically, we measure the molecule number using the following protocol. We first apply radio frequency (rf) to spin-flip the unpaired K atoms to another hyperfine state, which renders the unpaired K atoms invisible for subsequent molecular detection. We then sweep B back above the resonance to dissociate the molecules, and measure the number of resulting K atoms by spin-selective resonant absorption imaging. The conversion efficiency is determined by dividing this molecule number by the total number of K atoms measured when we do not apply the rf.

Bottom Line: Here we use such a system to prepare a density distribution where lattice sites are either empty or occupied by a doublon composed of an interacting Bose-Fermi pair.Additionally, we can probe the distribution of the atomic gases in the lattice by measuring the inelastic loss of doublons.These techniques realize tools that are generically applicable to studying the complex dynamics of atomic mixtures in optical lattices.

View Article: PubMed Central - PubMed

Affiliation: JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, USA.

ABSTRACT
Polar molecules in an optical lattice provide a versatile platform to study quantum many-body dynamics. Here we use such a system to prepare a density distribution where lattice sites are either empty or occupied by a doublon composed of an interacting Bose-Fermi pair. By letting this out-of-equilibrium system evolve from a well-defined, but disordered, initial condition, we observe clear effects on pairing that arise from inter-species interactions, a higher partial-wave Feshbach resonance and excited Bloch-band population. These observations facilitate a detailed understanding of molecule formation in the lattice. Moreover, the interplay of tunnelling and interaction of fermions and bosons provides a controllable platform to study Bose-Fermi Hubbard dynamics. Additionally, we can probe the distribution of the atomic gases in the lattice by measuring the inelastic loss of doublons. These techniques realize tools that are generically applicable to studying the complex dynamics of atomic mixtures in optical lattices.

No MeSH data available.


Related in: MedlinePlus