| Summary: | In our paper Can the Dipolar Interaction Suppress Dipolar Relaxation?, by using magnetic dysprosium atoms and an optical lattice we engineered the dipolar suppression of dipolar relaxation in an ultra-cold gas prepared in an excited Zeeman level. The atoms were confined to ultra-thin layers, with their magnetic moments aligned perpendicularly to the trap such that the dipolar interaction was purely repulsive. In such a configuration we observed an order of magnitude extension of lifetime in higher-lying states, opening up new possibilities for quantum simulation with multiple spin-species of highly magnetic atoms. Theoretical efforts applying Fermi’s golden rule numerically corroborated the observed suppression factors, including the fascinating dependence of dipolar relaxation on both the external magnetic field and the optical trap confinement.
In our paper Atomic physics on a 50 nm scale: Realization of a bilayer system of dipolar atoms, we utilize dysprosium’s disparate Clebsch-Gordan coefficients to produce two independent optical lattices capable of tuning the interlayer separation to 50 nm. The head-to-head orientation of the layers comprising the bilayer provide a new avenue of research for dipolar physics. Since the dipole-dipole interaction scales as 1/𝑟3, the reduction in interlayer separation leads to an approximately 500x enhancement of the dipole-dipole interaction. With our new subwavelength tool we explored dipolar coupling across the layers by observing both the transfer of thermal excitation, as well as the transfer of a dipole oscillation in the harmonic trap, from one layer to another. The Born approximation, applied to a dipolar interaction potential, yields excellent agreement with the observed interlayer thermalization rate. The observed interlayer transfer of a dipole oscillation in the harmonic trap results in an in-phase oscillation rather than the mean-field predicted out-of-phase oscillation, and can be partly ascribed to the friction force observed in the interlayer thermalization experiment, but may benefit from further exploration (e.g., correlated interlayer density fluctuations). The super-resolution provided by our bilayer is amazingly flexible, limited only by the width of the layer, such that the interlayer separation can be tuned arbitrarily small if sufficient localization of the layers is achieved. Such a tool will hopefully prove highly useful for the exploration of dipolar physics on a previously unattainable length scale.
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