More Like this

1. Co-trapped heteronuclear Rydberg and Collisional Interactions in an Optical Dipole Trap

   Ebert, MATTHEW ; Poole, Cody ; XIAOYU, Jiang ; KEARNS, Genevieve ; TIESINGA, Eite ; SAFFMAN, Mark ( January 2019 , APS DAMOP meeting, May 2019 Milwaukee)

   We present progress in demonstrating Rydberg interactions between a single Rb and a single Cs atom simultaneously trapped in a single 1064 nm optical tweezer. Rydberg levels in heteronuclear systems have different quantum defects, as opposed to homonuclear systems, and can therefore be chosen to minimize the Forster defect and increase the Rydberg interaction strength beyond symmetric Rydberg pairs at comparable energy levels. Additionally, multispecies systems are distinguishable and can be frequency multiplexed in a straightforward manner, enabling crosstalk free ancilla measurements for quantum error correction. To determine the feasibility of co-trapped heteronuclear samples for quantum information and communication applications, we also measure the heteronuclear collision rates between single Rb and single Cs atoms and resolve differences in the hyperfine collision rates. Photoassociation rate of the atoms into a molecular state via the 1064 nm trap laser is also measured. 

   more » « less
2. A reconfigurable blue-detuned lattice for neutral atom quantum computing

   GRAHAM, T. ; POOLE, C ; JIANG, X ; MARRA, Z ; GRINKEMEYER, B ; HICKMAN, G ; CHEREK, J ; EBERT, M ; SAFFMAN, M. ( May 2019 , DAMOP 2019)

   We present recent progress towards building a neutral atom quantum computer. We use a new design for a blue-detuned optical lattice to trap single Cs atoms. The lattice is created using a combination of diffractive elements and acousto-optic deflectors (AODs) which give a reconfigurable set of cross-hatched lines. By using AODs, we can vary the number of traps and size of the trapping regions as well as eliminate extraneous traps in Talbot planes. Since this trap uses blue-detuned light, it traps both ground state atoms and atoms excited to the Rydberg state; moreover, by tuning the size of the trapping region, we can make the traps “magic” for a selected Rydberg state. We use an optical tweezer beam for atom rearrangement. When loading atoms into the array, trap sites randomly contain zero or one atoms. Atoms are then moved between different trapping sites using a red-detuned optical tweezer. Optimal atom rearrangement is calculated using the “Hungarian Method”. These rearrangement techniques can be used to create defect-free sub-lattices. Lattice atoms can also be used as a reservoir for a set of selected sites. This allows quick replacement of atoms, and increased data rate, without reloading from a MOT. 

   more » « less
3. A reconfigurable blue-detuned lattice for neutral atom quantum computing

   Graham, Trent ; Poole, Cody ; Xiaoyu, Jiang ; Marra, Alphonse ; Grinkemeyer, Brandon ; Hickman, Garrett ; Cherek, Josh ; Ebert, Matthew ; Saffman, Mark ( May 2019 , 50th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics APS Meeting)

   We present recent progress towards building a neutral atom quantum computer. We use a new design for a blue-detuned optical lattice to trap single Cs atoms. The lattice is created using a combination of diffractive elements and acousto-optic deflectors (AODs) which give a reconfigurable set of cross-hatched lines. By using AODs, we can vary the number of traps and size of the trapping regions as well as eliminate extraneous traps in Talbot planes. Since this trap uses blue-detuned light, it traps both ground state atoms and atoms excited to the Rydberg state; moreover, by tuning the size of the trapping region, we can make the traps “magic” for a selected Rydberg state. We use an optical tweezer beam for atom rearrangement. When loading atoms into the array, trap sites randomly contain zero or one atoms. Atoms are then moved between different trapping sites using a red-detuned optical tweezer. Optimal atom rearrangement is calculated using the “Hungarian Method”. These rearrangement techniques can be used to create defect-free sub-lattices. Lattice atoms can also be used as a reservoir for a set of selected sites. This allows quick replacement of atoms, and increased data rate, without reloading from a MOT. 

   more » « less
4. Spectroscopy of the 85 Rb 4 D3/2 state for hyperfine-structure determination

   https://doi.org/10.1088/1367-2630/acf405  

   Duspayev, A. ; Raithel, G. ( September 2023 , New Journal of Physics)

   We report a measurement of the hyperfine-structure constants of the⁸⁵Rb 4$D_{3/2}$state using two-photon optical spectroscopy of the 5$S_{1/2}\to$4$D_{3/2}$transition. The spectra are acquired by measuring the transmission of the low-power 795 nm lower-stage laser beam through a cold-atom sample as a function of laser frequency, with the frequency of the upper-stage, 1476 nm laser fixed. All 4 hyperfine components of the$4D_{3/2}$state are well-resolved in the experimental data. The dominant systematic is the light shift from the 1476 nm laser, which is addressed by extrapolating line positions measured for a set of 1476 nm laser powers to zero laser power. The analysis of our experimental data yields both the magnetic-dipole and electric-quadrupole constants for the⁸⁵Rb 4$D_{3/2}$level, without using earlier hyperfine measurements of other atomic levels. The respective results,$A=$7.419(35) MHz and$B=$4.19(19) MHz, are discussed in context with previous works. Our investigation may be useful for optical atomic clocks for precision metrology and emerging atom-based quantum technologies, all-infrared excitation of Rb Rydberg levels, and molecular physics.

    

   more » « less
5. Observation of Rydberg exciton polaritons and their condensate in a perovskite cavity

   https://doi.org/10.1073/pnas.1909948116  

   Bao, Wei ; Liu, Xiaoze ; Xue, Fei ; Zheng, Fan ; Tao, Renjie ; Wang, Siqi ; Xia, Yang ; Zhao, Mervin ; Kim, Jeongmin ; Yang, Sui ; et al ( October 2019 , Proceedings of the National Academy of Sciences)

   The condensation of half-light half-matter exciton polaritons in semiconductor optical cavities is a striking example of macroscopic quantum coherence in a solid-state platform. Quantum coherence is possible only when there are strong interactions between the exciton polaritons provided by their excitonic constituents. Rydberg excitons with high principal value exhibit strong dipole–dipole interactions in cold atoms. However, polaritons with the excitonic constituent that is an excited state, namely Rydberg exciton polaritons (REPs), have not yet been experimentally observed. Here, we observe the formation of REPs in a single crystal CsPbBr 3 perovskite cavity without any external fields. These polaritons exhibit strong nonlinear behavior that leads to a coherent polariton condensate with a prominent blue shift. Furthermore, the REPs in CsPbBr 3 are highly anisotropic and have a large extinction ratio, arising from the perovskite’s orthorhombic crystal structure. Our observation not only sheds light on the importance of many-body physics in coherent polariton systems involving higher-order excited states, but also paves the way for exploring these coherent interactions for solid-state quantum optical information processing. 

   more » « less