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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.


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The d-wave Feshbach resonance.(a) The theoretical K-Rb scattering length, aK-Rb, is shown as a function of the magnetic field for the broad s-wave Feshbach resonance and a narrow d-wave resonance, based on the formula and parameter values described in Methods. (b) Crossing the d-wave resonance affects the pair states for K and Rb. Dashed and solid arrows show the effect of the variable rate sweep that creates doublons and the subsequent fast magneto-association sweep, respectively. Dashed vertical lines mark the positions of the Feshbach resonances. (c) Measurement of molecule conversion efficiency at 35 ER (circles) and 30 ER (diamonds), with the latter data exponentiated by (35/30)3/4=1.12 to account for the expected dependence on lattice depth. The solid curve shows a fit to a Landau-Zener probability P (see text), which gives a resonance width of 9.3(7) × 10−4 mT. (d) The magnetic field at which this resonance occurs is determined by sweeping up to various fields at 0.018 mT ms−1, then sweeping down at 0.18 mT ms−1. The position of the resonance extracted from this measurement at Vlatt=35ER is 54.747(1) mT. All error bars represent 1−σ standard error.
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f2: The d-wave Feshbach resonance.(a) The theoretical K-Rb scattering length, aK-Rb, is shown as a function of the magnetic field for the broad s-wave Feshbach resonance and a narrow d-wave resonance, based on the formula and parameter values described in Methods. (b) Crossing the d-wave resonance affects the pair states for K and Rb. Dashed and solid arrows show the effect of the variable rate sweep that creates doublons and the subsequent fast magneto-association sweep, respectively. Dashed vertical lines mark the positions of the Feshbach resonances. (c) Measurement of molecule conversion efficiency at 35 ER (circles) and 30 ER (diamonds), with the latter data exponentiated by (35/30)3/4=1.12 to account for the expected dependence on lattice depth. The solid curve shows a fit to a Landau-Zener probability P (see text), which gives a resonance width of 9.3(7) × 10−4 mT. (d) The magnetic field at which this resonance occurs is determined by sweeping up to various fields at 0.018 mT ms−1, then sweeping down at 0.18 mT ms−1. The position of the resonance extracted from this measurement at Vlatt=35ER is 54.747(1) mT. All error bars represent 1−σ standard error.

Mentions: We begin by investigating a narrow d-wave Feshbach resonance14151617 that is located less than 0.1 mT above the 0.3-mT-wide s-wave resonance that is used for making molecules (Fig. 2a). With a pair of atoms confined in the same lattice site, the on-site density is orders of magnitude higher than that in ordinary optical traps, and thus this narrow Feshbach resonance can adversely affect the magneto-association process, where B is swept down from above the s-wave resonance to create molecules. Crossing the d-wave resonance too slowly will produce d-wave molecules, which will not be coupled to the ground state by the subsequent STIRAP laser pulses, as the process is weak and off resonance. If B is swept sufficiently fast to be diabatic for this narrow resonance (but still slow enough to be adiabatic for the broad s-wave resonance), crossing the d-wave resonance has no impact; however, the high effective densities at each site in an optical lattice can make it challenging to sweep fast enough. Although we study here specific resonances for the K-Rb system, the possibility of having to cross other Feshbach resonances and the issue of sweep speeds are general to magneto-association of atoms in an optical lattice.


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)

The d-wave Feshbach resonance.(a) The theoretical K-Rb scattering length, aK-Rb, is shown as a function of the magnetic field for the broad s-wave Feshbach resonance and a narrow d-wave resonance, based on the formula and parameter values described in Methods. (b) Crossing the d-wave resonance affects the pair states for K and Rb. Dashed and solid arrows show the effect of the variable rate sweep that creates doublons and the subsequent fast magneto-association sweep, respectively. Dashed vertical lines mark the positions of the Feshbach resonances. (c) Measurement of molecule conversion efficiency at 35 ER (circles) and 30 ER (diamonds), with the latter data exponentiated by (35/30)3/4=1.12 to account for the expected dependence on lattice depth. The solid curve shows a fit to a Landau-Zener probability P (see text), which gives a resonance width of 9.3(7) × 10−4 mT. (d) The magnetic field at which this resonance occurs is determined by sweeping up to various fields at 0.018 mT ms−1, then sweeping down at 0.18 mT ms−1. The position of the resonance extracted from this measurement at Vlatt=35ER is 54.747(1) mT. All error bars represent 1−σ standard error.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: The d-wave Feshbach resonance.(a) The theoretical K-Rb scattering length, aK-Rb, is shown as a function of the magnetic field for the broad s-wave Feshbach resonance and a narrow d-wave resonance, based on the formula and parameter values described in Methods. (b) Crossing the d-wave resonance affects the pair states for K and Rb. Dashed and solid arrows show the effect of the variable rate sweep that creates doublons and the subsequent fast magneto-association sweep, respectively. Dashed vertical lines mark the positions of the Feshbach resonances. (c) Measurement of molecule conversion efficiency at 35 ER (circles) and 30 ER (diamonds), with the latter data exponentiated by (35/30)3/4=1.12 to account for the expected dependence on lattice depth. The solid curve shows a fit to a Landau-Zener probability P (see text), which gives a resonance width of 9.3(7) × 10−4 mT. (d) The magnetic field at which this resonance occurs is determined by sweeping up to various fields at 0.018 mT ms−1, then sweeping down at 0.18 mT ms−1. The position of the resonance extracted from this measurement at Vlatt=35ER is 54.747(1) mT. All error bars represent 1−σ standard error.
Mentions: We begin by investigating a narrow d-wave Feshbach resonance14151617 that is located less than 0.1 mT above the 0.3-mT-wide s-wave resonance that is used for making molecules (Fig. 2a). With a pair of atoms confined in the same lattice site, the on-site density is orders of magnitude higher than that in ordinary optical traps, and thus this narrow Feshbach resonance can adversely affect the magneto-association process, where B is swept down from above the s-wave resonance to create molecules. Crossing the d-wave resonance too slowly will produce d-wave molecules, which will not be coupled to the ground state by the subsequent STIRAP laser pulses, as the process is weak and off resonance. If B is swept sufficiently fast to be diabatic for this narrow resonance (but still slow enough to be adiabatic for the broad s-wave resonance), crossing the d-wave resonance has no impact; however, the high effective densities at each site in an optical lattice can make it challenging to sweep fast enough. Although we study here specific resonances for the K-Rb system, the possibility of having to cross other Feshbach resonances and the issue of sweep speeds are general to magneto-association of atoms in an optical lattice.

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